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Pelage of Columbian black tail deer odocoileus hemionus columbianus (Richardson) a study Raddi, Arvind Govind 1967

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THE PELAGE OP COLUMBIAN BLACK TAIL DEER ODOCOILEUS HEMIONMS COLUMBIANUS (Richardson) — a Study by ARVTND GOVIND RADDI B.Sc. University of Poona 1957 M.Sc. University of Bombay 1959 A.I.F.C. Indian Forest College, Dehra Dun 1962 A Thesis submitted.in p a r t i a l f u l f i l l m e n t of the requirements f o r the degree of Doctor of Philosophy i n the Department of Zoology We accept t h i s thesis as conforming to the required standard University of B r i t i s h Columbia November 1967 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r a n a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l m a k e i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d S t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may b e g r a n t e d b y t h e H e a d o f my D e p a r t m e n t o r b y h.Us r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t b e a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t o f Zoology  T h e U n i v e r s i t y o f B r i t i s h C o l u m b i a V a n c o u v e r 8, C a n a d a D a t e 1 4 t h December 19^7» i ABSTRACT The hairs and the f o l l i c l e s i n which they a r i s e constitute the mammalian p i l a r y system. I t i s a dynamic b i o l o g i c a l system i n which the h a i r f o l l i c l e s undergo c y c l i c a l l y p a r t i a l regression and redevelopment, producing simultaneously new hairs to replace the old which are due to be shed. The pelage i s important i n maintaining the animals thermal equilibrium, protection from abrasion and i n display etc. Nonetheless, knowledge of cervid p i l a r y system i s extremely l i m i t e d . The present study covers i t s development, morphology, moult and the annual hair c y c l e . E f f e c t s on the cervid pelage of experimentally induced adverse n u t r i t i o n , as well as varying habitat, are also studied. Morphogenesis of f o l l i c l e s and development stages of the hair follow the general mammalian pattern. The d e t a i l s of anatomy and development have been recorded. Large guard hair f o l l i c l e s , which during development grow faster and a t t a i n larger dimensions, have been recorded for the f i r s t time i n ungulates. They are rela t e d to "T y l o t r i c h s " referred to by S t r a i l e ( i 9 6 0 ) and produce longer h a i r . Both primary and secondary f o l l i c l e s are present. The f i r s t formed secondaries are larger and like„the primaries possess a sweat gland, sebaceous gland and arrector p i l i i muscle. Like primaries they too produce medullated h a i r s . The l a t e r secondaries form non medullated woolly underhairs. Paired and branched f o l l i c l e s have been recorded amidst secondaries. 11 The primaries give r i s e to the overcoat and the secondaries to the undercoat. The percentage of non medullated hairs i n the b i r t h coat of the fawn i s les s than i n other coats. The hair f o l l i c l e s i n which they a r i s e continue to form postnatally and become f u l l y f unctional i n fawn winter coat. Adult winter coat d i f f e r s from adult summer coat i n colouration, length and diameter, here there i s a greater development of medulla, and a well developed woolly undercoat i s present. The l a t t e r i s fu n c t i o n a l l y lacking i n adult summer coat. The autumn moult (adult) begins on the flanks and spreads cephalad and caudad. In the summer coat moult i s caudad. The fawn b i r t h coat moult i s caudad. Their d e t a i l s have been documented. The winter coat i s greyish i n colour while the summer coat i s reddish yellow. The winter colouration i s a product mostly of the colour zone i n the top 10 mm of hair length. The winter c l a t guard hairs stand more erect, because of the padding provided by the woolly undercoat. The adult summer coat has more sloping hairs and Its colouration i s the product of the top 20 mm of the t o t a l hair length. The c h a r a c t e r i s t i c s of hair scale are record-ed for representative hair types. A morphometric study of hair samples from i d e n t i c a l regions i n the coatscoftblack t a i l deer has been attempted and the features recorded. The hair increases i n coarseness and diameter from fawn b i r t h coat up to adult winter coat. The ha i r length increases up to adult summer coat but decreases i n adult winter coat. The winter coat exhibited a consistent length to diameter r e l a t i o n s h i p but t h i s was lacking i n summer coat. The hairs i n i i i white-spots of the fawn b i r t h coat d i f f e r e d only i n respect of colour from the adjoining non-spotted area and not i n any other external morphological respect. Fortnightly skin biopsy samples were taken by means of a trephine; t h e i r h i s t o l o g i c a l study provided data on the annual hair cycle. The overcoat hairs moult twice while the undercoat hairs are shed only once. The statement by Lyne ( 1 9 6 6 ) that "the rate of f o l l i c l e development Is inversely proportional to the size of the mature f o l l i c l e " Is true for guard h a i r s . F i r s t formed secondaries , however, reach resting stages e a r l i e r than do the l a t e r formed secondaries. Rate of growth i s greater,Jin larger f o l l i c l e s , which though not much advanced developmentally, reach larger size-. E f f e c t s of adverse n u t r i t i o n on pelage have been studied experimentally, oh normally growing hairs as well as those induced a r t i f i c i a l l y by plucking resting h a i r s . Hair length and diameter were reduced i n underfed animals and i n i t i a t i o n of new ha i r growth was delayed. Reduction i n width of medulla appeared to be responsible for most of the reduction i n hair diameter. The medulla i s an important insulator, as can be seen from i t s greater extent i n Alaskan forms compared with those from Southern C a l i f o r n i a l i v i n g i n dry hot habitats. Regression analysis Indicated that i n underfed animals, though actual hair diameter was l e s s , r e l a t i v e increase i n diameter for a unit increase of length was greater than that i n well fed animals. Thus when nutrients are li m i t e d , growth i n hair diameter (in turn dependent on size of medulla) enjoys a p r i o r i t y over growth i n length. F i n a l l y i t i s f e l t that to comprehend properly the phenomenon of h a i r growth i n cervids future investigations could f r u i t f u l l y concentrate on the biology of c e l l s i n the f o l l i c l e base and the dermal p a p i l l a . The r o l e of dermal p a p i l l a i n hair growth and the process of d i f f e r e n t i a t i o n of d i f f e r e n t f o l l i c l e layers are of great significance but need to be well understood. I ACKNOWLEDGEMENT v It i s a pleasure to express my sincere gratitude, to my Supervisor Dr. I McTaggart Cowan, Dean, Faculty of Graduate studies, University of B r i t i s h Columbia for h i s guidance, encouragement and above a l l for the most understanding attitude which he maintained throughout the course of my stay at U.B.C. and to Dr. J.K. Ling for i n i t i a t i n g me into the study of pelage and f o r h i s help and guidance during his tenure as a post doctoral fellow at the Dept. of Zoology. Sincere thanks are also due to Dr. H.D. Fisher and Dr. C. Finnegan for permitting the use of t h e i r laboratory f a c i l i t i e s . I also thank Dr. P.J. Bandy and Mr. Don Blood of the B.C. Fish and Game Dept. f o r t h e i r help i n c o l l e c t i o n of deer skins, Dr. H.C. Nordan for h i s help i n setting up the n u t r i t i o n experiment, and Dr. P. Ford for h i s advice i n h i s t o l o g i c a l work. I also thank Dr. Longhurst and Dr. Kline f o r supplying us with hides of Southern C a l i f o r n i a n and Alaskan black t a i l deer. I am also thankful to my f r i e n d and colleague Dr. Jagdlsh C. Nautiyal of the Indian Forest Service, then In the Faculty of Forestry, UBC, for h i s help i n work involving use of a computer. Mrs. H. Froese and Miss J . Osborne of the Faculty of Forestry were also most h e l p f u l i n thi s respect. Many of my colleagues i n the Dept i of Zoology were always ready to help. In p a r t i c u l a r I must thank Mr. Ray Addison who helped time and time again during skin biopsy sampling. I also thank Mrs Jephson, who did the typing, for her patience with the thesis manuscript, and Miss R. B r o i l who translated some s c i e n t i f i c papers for me. I am also g r a t e f u l to the External Aid Office of the Government of Canada, for f i n a n c i a l support provided by award of a Canadian Commonwealth Scholarship, and to the Government of India and Government of Maharashtra f o r granting me study leave to u t i l i z e the same. I thank a l l the members of my advisory committee for the i r h e l p f u l c r i t i c i s m , i n p a r t i c u l a r Dr. D. Chitty; l i s t e n i n g to his views on matters s c i e n t i f i c or otherwise was an enriching experience. F i n a l l y special thanks are due to my wife Neelima for the very cheerful support and help which she consistently extended throughout the course of t h i s undertaking. v i i TABEL OF CONTENTS Chapter Page Abstract i Acknowledgement v Table of contents v i i Table s x I l l u s t r a t i o n s x i i I General introduction 1 Introduction 1 Humans 2 Domestic animals of economic Importance 2 a) Sheep 2 b) Cattle 2 Animals with economically valuable pelts 3 II The cervid pelage.... 5 III Prenatal development of the p i l a r y system In deer 11 Introduction. 11 Materials and methods 11 Observations 13 F o l l i c l e and hair development 1 8 Large guard hair f o l l i c l e s 23 The intermediate guard hair f o l l i c l e s 33 Central intermediate guard hair f o l l i c l e s . . . . 35 L a t e r a l intermediate guard hair f o l l i c l e s . . . . 38 Woolly under hair f o l l i c l e s . . . . 39 F o l l i c l e anatomy. 4 0 The connective tissue sheath 4 ? The glassy membrane 4 ? External root sheath 4 7 The inner root sheath 4 8 Henle 1 s layer 51 Huxley's layer 51 Inner root sheath c u t i c l e . 51 The f i b r e anatomy 52 The hair c u t i c l e 52 The cortex............... ° 52 The medulla 53 The f o l l i c l e bulb and dermal p a p i l l a 53 Melanocytes 55 Sweat gland 55 Sebaceous gland 58 Arrector p i l i l muscle 61 Ental swelling 6 l The hair canal 62 Paired f o l l i c l e s 62 v i i i Chapter Page III Branched f o l l i c l e s 63 F o l l i c l e density 63 Integumentary layers •> 64 The epidermis 64 Periderm 64 The dermis 67 Summary 70 IV Pelage morphology and moult patterns 74 Introduction 74 Material and methods 7^ Observations 76 Hair c h a r a c t e r i s t i c s 76 Hair types.. 76 Large guard hairs 76 Intermediate guard hairs 79 Woolly under hairs 79 Beard type 79 White tipped hairs 79 Cortex, medulla and s c u t e l l a t i o n 82 Colouration 85 Coat description.and pattern of moult 87 Fawn b i r t h coat 87 Moult i n the fawn b i r t h coat 89 Fawn winter coat 93 Moult from fawn winter coat to adult summer coat 93 Adult summer coat 9^ Moult from adult summer to adult winter coat. 95 Adult winter coat 99 Moult from adult winter coat to adult summer coat 99 Summary 103 V The ha i r cycle of the black t a l l deer 105 Introduction 105 Material and methods 105 Observations ... 108 Summary 115 VI The morphometry of black t a i l deer 117 Introduction 117 Material and methods 117 Observations 118 Length 118 Diameter 123 Colouration*^.. xsaa 128 Black coloured zone 128 Yellcw coloured zone Grey or reddish-yellow coloured zone. White coloured zone Summary Ef f e c t of adverse n u t r i t i o n and v a r i a t i o n of habitat on cervid pelage Introduction. Material and methods Observations a) Normally grown winter pelage on control and experimental animals b) The a r t i f i c i a l l y induced h a i r cycles... c) H i s t o l o g i c a l changes during the a r t i f i c a l hair cycle Summary «• General discussion..... F o l l i c l e development and anatomy Epidermis and dermis Hair types and morphology Adaptive value Moult E f f e c t of adverse n u t r i t i o n Bibliography Appendices I Weekly weight data II Feed intake i n c a l o r i e s (weekly average) I l l H i s t o l o g i c a l treatment IV Key to abbreviations used i n i l l u s t r a t i o n s LIST OP TABLES Number -Page 1 Basic data on foetuses sampled 1 2 2 F o l l i c l e types and t h e i r development stages... 3 4 3 Annual cycle of the black t a i l deer 1 1 6 4- Nested analysis of variance hair length 1 1 9 5 Lengths of hair samples i n mm 1 2 1 6 Duncan's multiple range test for h a i r lengths. 1 2 2 a) Within coats b) Regions within coats c) Hair types within regions 7 Nested analysis of variance hair diameter 1 2 3 8 Diameter of hair samples i n microns 1 2 6 9 Duncan*s multiple range test for hair diameter i n microns 1 2 7 a) Within coats b) Regions within coats c) Hair types within regions 1 0 Black coloured zone (r a t i o of black coloured zone to t o t a l h a i r length 1 3 0 1 1 Nested analysis of variance. Black coloured Z O n e -r-r 1 3 1 1 2 Duncan's multiple range te s t for black coloured zone 1 3 2 a) Within coats b) Regions within coats c) Hair types within regions 1 3 Nested analysis of variance. Yellow coloured zone 1 3 3 14- Yellow coloured zone extent (ratio of yellow coloured zone to t o t a l h a i r length 13^-1 5 Duncan's multiple range test for yellow coloured zone 1 3 5 a) Within coats b) Regions within coats c) Hair types within regions x i LIST OF TABLES (cont'd) Number Page 1 6 Nested analysis of variance of grey/reddish yellow zone 1 3 6 1 7 Grey or reddish-yellow zone extent 1 3 7 18 Duncan's multiple range test for grey or reddish yellow zone 1 3 8 a) Within coats b) Region within coats c) Hair types within region 1 9 White coloured zone 140 2 0 Nested analysis of variance. White coloured zone 1^-1 2 1 Duncan's multiple range test for white coloured zone > • 142 a) Within coats b) Regions within coats c) Hair types within region 2 2 Composition of adult r a t i o n 1 5 ^ 2 3 Nutrient composition of r a t i o n 1 5 5 24 Digestible energy content of the adult r a t i o n . 1 5 6 2 5 Breaking strength large guard hairs 1 6 0 2 6 Breaking strength of intermediate guard h a i r s . 1 6 0 2 7 Intermediate guard hairs (fibre weight) 161 x i i ILLUSTRATIONS Figures Page 1 Stages 1 to 1 0 In the development of mammalian hair f o l l i c l e as shown i n c a t t l e . After Lyne and Heideman ( 1 9 5 9 ) 1^ 2 Grouping of primary and secondary f o l l i c l e s i n adult deer. Transverse section 2 0 3A Deer primary f o l l i c l e s general view. Longitudinal section 2 0 3B Deer secondary f o l l i c l e . General view Longitudinal section.. 2 0 4 Developing skin and hair f o l l i c l e s . 1 1 2 mm stage 20 4.1 Longitudinal section 2 0 5 Developing skin and hair f o l l i c l e s . 2 0 2 mm stage 5.1 Longitudinal section 25 5.2 Transverse section 2 5 6 Developing skin and f o l l i c l e s . 2 3 5 Eim stage 6.1 Longitudinal section 25 6 i 2". Transverse section.... 2 5 7 Developing skin and f o l l i c l e s . 2 6 9 mm stage 7.1 Longitudinal section. 2 7 7.2 Transverse section 27 8 Developing skin and hair f o l l i c l e s . 2 8 7 nun stage 8.1 Longitudinal section 2 7 8.2 Transverse section 27 9 Developing skin and h a i r f o l l i c l e s . 3 2 1 mm stage 9.1 Longitudinal section 2 9 9.2 Transverse section 2 9 x i i i ILLUSTRATIONS (cont»d) Figure Page 10 Developing skin and hair f o l l i c l e s . 44-8 mm stage 10.1 Longitudinal section 29 10.2 Transverse section 29 11 Large guard hair f o l l i c l e 31 11.1 Longitudinal section. 287 mm stage 31 11.2 Transverse section with adjoining f o l l i c l e s 269 mm stage 31 11.3 Longitudinal section showing d i l a t e d part 287 mm stage 31 11.4 Close of the f o l l i c l e bulb. 287 mm stage 31 12 Central intermediate guard hair f o l l i c l e s . . . . 12.1 Longitudinal section 37 12.2 Transverse section........ 37 13 White tipped hair f o l l i c l e s (fawn b i r t h coat) and l a t e r a l intermediate guard hair f o l l i c l e s 13.1 Longitudinal section white tipped hair f o l l i -cle 37 13.2 Transverse section.. 37 14 Secondary f o l l i c l e s . 14.1 Developing secondary f o l l i c l e s . Longitudinal section 4-2 14.2 Paired secondary f o l l i c l e developing, l o n g i t u d i n a l section 4-2 14-.3 Branching secondary f o l l i c l e s . Longitudinal section 4-2 14.4 F i r s t formed secondary f o l l i c l e s and l a t e r formed secondary f o l l i c l e s . Longitudinal section 4-2 14-.5 Paired secondary f o l l i c l e s . Adult material. Longitudinal section .'. 44 x i v .ILLUSTRATIONS (cont»d) 'igures Page 1 4 . 6 Secondary f o l l i c l e . " Adult material. Longitudinal section 44 1 5 Details of f o l l i c l e anatomy, (sheep) 1 5 . 1 Longitudinal section of primary f o l l i c l e (sheep) 46 1 5 . 2 Details of the bulb. Longitudinal section " 46 1 5 . 3 Details of medulla (sheep) 46 1 6 Deer primary f o l l i c l e bulb 1 6 . 1 Close up of the f o l l i c l e bulb 5 0 1 6 . 2 C e l l layers i n f o l l i c l e bulb 5 0 1 7 Medulla formation 1 7 . 1 Medulla i n primary hair f o l l i c l e 5 0 1 7 . 2 Medulla i n white tipped hair of fawn b i r t h coat. 5 0 18 Sweat gland 1 8 . 1 Sweat gland forming. 2 0 2 mm stage, l o n g i t u d i n a l section 5 7 1 8 . 2 Sweat gland at 2 3 6 mm stage. Longitudinal section 5 7 1 8 . 3 Sweat gland at 2 6 9 mm stage. Longitudinal section 5 7 1 8 . 4 Sweat gland i n adult . Longitudinal section... 5 7 19 Sebaceous gland 1 9 . 1 Sebaceous gland rudiment. Longitudinal section. 2 3 5 stage 6 0 1 9 . 2 Sebaceous gland at 2 6 9 mm stage. Longitudinal section 6 0 1 9 *3 Sebaceous gland opening i n adult. Longitudinal section 6 0 1 9 . ^ Sebaceous gland and f o l l i c u l a r f o l d i n adult. Longitudinal section 6 0 XV ILEUS TRATIONS (cont'd) Figures Page 20 A r r e c t o r i s p i l l i i n adult material....... 66 21 Melanin i n growing hair f o l l i c l e 66 22 Dermis 22.1 Dermis at early stage. 202 mm stage 66 22.2 Dermis i n adult 66 23 Epidermis 23.1 Developing epidermis and dermis. 4-6.2 mm stage 69 .-23;2 Developing epidermis. Two layered stratum spinosum. 112 mm stage 69 23.3 Three layered stratum spinosum. 181.5 mm stage 69 23.4 Adult epidermis and portions of dermis 69 24 Skin surface view. 269 mm stage. Large guard hairs emerging 78 25 Skin surface view. 287 mm stage. Intermediate guard hairs also emerging 78 26 Fawn b i r t h coat hair array 78 27 Fawn winter coat hair array 78 28 Adult summer coat.. 28.1 Summer coat hair array 81 28.2 .Close up of summer coat 81 29 Adult winter coat 29.1 Winter coat hair array 81 29.2 Close up of winter coat 81 30 Antro posterior distance between scale margins. After Spence (1963) 83 31 Hair scale arrangement. After Spence ( I963). . 83 32 Deer body regions xvi ILLUSTRATIONS (cont'd) Figures Page 32.1 Different body regions of the black t a i l deer. Side view.... 88 32.2 Head front view 88 32.3 Posterior view of the animal............ 88 33 Moult stage 33.1 Fawn i n b i r t h coat 92 33.2 Fawn moult stage 1 (birth to winter coat)..... 92 33.3 Fawn moult stage 2 " " " " 92 33.4 Fawn moult stage 3 • " " " 92 34 Fawn i n winter coat 92 35 Adult i n summer coat 97 36 Moult from adult summer coat to adult winter coat. 36.1 Stage 1 97 36.2 Stage 2 97 36.3 Stage 3 "•' 97 37 Adult i n winter coat 101 38 Moult from adult winter coat to adult summer coat 38.1 Stage 1 101 38.2 Stage 2 101 38.3 Stage 3 101 39 Photograph of trephine used for biopsy sampling 1 0 7 40 Fortnightly sampling schedule 107 41 Deer f o l l i c l e s i n Anagen I l l 4-1.1 Primary f o l l i c l e s (Intermediate guard h a i r s ) . . I l l x y i i ILLUSTRATIONS (cont»a.) Figures Page 4-1.2 Secondary f o l l i c l e s I l l 4-2 Intermediate guard hair f o l l i c l e i n catagen.... I l l 43 Primary f o l l i c l e i n Telogen 43.1 Base of f o l l i c l e i n Telogen I l l 43.2 Close up of the bulb i n Telogen I l l 4-3.3 Dermal p a p i l l a i n Telogen 114 43.4 Close up of spatulate dermal p a p i l l a 3114 43.5 New hair growing i n re s t i n g f o l l i c l e . Longitudinal section 114 43.6 New hair growing i n old resting f o l l i c l e . Transverse section 114 4-4 Diagramatic representation of annual hair cycle l l 6 a 45 Guard hair length r e l a t i o n s h i p i n d i f f e r e n t coats of the black t a i l deer with t h e i r major h a i r colour zones..... 120 4-6 Guard hair diameter r e l a t i o n s h i p i n d i f f e r e n t coats of the black t a i l deer 125 4? Percentage of d i f f e r e n t colour zones i n coat types i n r e l a t i o n to t o t a l hair length 129 48 Percentage of d i f f e r e n t coloured zones In v i s i b l e portion of pelage h a i r , (assumed to be 10 mm i n winter coat and 20 mm i n summer coat). 14-4 4-9 Diagram representing p o s i t i o n of guard hairs i n summer coat and winter coat 14-5 50 Regression l i n e comparing length and diameter r e l a t i o n s h i p i n : 14? a) Fawn spotted region against fawn non spotted region. b) Adult winter coat 51 Hair length and diameter r e l a t i o n s h i p i n fawn b i r t h coat, i n area other than white spots 148 52 Hair length and diameter r e l a t i o n s h i p i n fawn b i r t h coat white spotted region 149 x v i i i ILLUSTRATIONS (cont'd) igures Page 53 Hair length and diameter r e l a t i o n s h i p i n adult winter coat 150 5 ^ Hair length and diameter r e l a t i o n s h i p i n adult summer coat 151 55 VJinter coat hair length and diameter r e l a t i o n -ship i n changing habitats I63 56 A r t i f i c i a l l y induced hair cycle 56.1 Plucked f o l l i c l e s regrowing i n underfed animal. F i r s t week. Ul6 , 166 56.2 Plucked f o l l i c l e s regrowing i n well fed animal. F i r s t week. w 4 . . 166 57 W4- i . e . well fed animal. Hairs emerging i n four weeks 166 58 Underfed animal. Two months a f t e r plucking h a i r growth i s active 166 59 Well fed animal i n winter pelage 169 60 Underfed animal i n winter pelage 169 61 Hairs grow fas t e r at s i t e s of sampling i n deer. 169 62 Winter coat guard hair length and diameter re l a t i o n s h i p i n well fed animal 170 63 Winter coat guard hair length and diameter r e l a t i o n s h i p i n underfed animal 171 64 Regression l i n e comparing length and diameter r e l a t i o n s h i p between well fed and underfed winter coat guard hair samples 172 Chapter I GENERAL INTRODUCTION Introduction Hairs are an important mammalian c h a r a c t e r i s t i c . A l l mammals possess them i n varying degrees. They are produced i n the hair f o l l i c l e by c e l l s of epidermal o r i g i n . The most important function performed by pelage appears to be a s s i s t i n g the animal to maintain a thermal equilibrium and to overcome rigours of cl i m a t i c fluctuations (Scholander et a l 1 9 5 0 , Hart 1 9 5 6 ) . The hair type constituting the pelage, help to trap a cushion of a i r and b u i l d up a thermal gradient from skin to the outer environment (Ling I 9 6 5 K Mammals inhabitating colder regions possess c h a r a c t e r i s t i c a l l y thick pelage as opposed to those occurring i n warmer regions. The thick pelage so advanta-geous i n winter i s a disadvantage during warm seasons, even i n colder regions. To obviate t h i s d i f f i c u l t y mammals moult and the pelage d i f f e r s between cold and hot seasons. The i n d i v i d u a l hair constituting the pelage may be coloured d i f f e r e n t l y along t h e i r length and together lend c h a r a c t e r i s t i c colouration to the pelage. Generally the colouration i s darker i n winter and l i g h t e r i n summer. The pelage i s also made use of i n the animals behaviour problem and displays; e.g. Cowan and Geist ( 1 9 6 1 ) , and Geist ( 1 9 6 6 ) . In addition pelage i s responsible for protecting the animal from abrasion and external damage. In many species i t also acts as an e f f e c t i v e water proofing agent (Flesch 1 9 5 ^ ) • 2 These attr i b u t e s i n themselves are s u f f i c i e n t to j u s t i f y investigations of pelage from ph y s i o l o g i c a l , anatomical, and ethological point of view. Unfortunately to t h i s date r e l a t i v e l y few mammalian species have been investigated. B a s i c a l l y the following have been the objects of research, and the topics inves-tigated range from f o l l i c l e development, morphology, to annual ha i r cycles and moulting. 1 . Humans Medical determatology has covered the f i e l d of human hair growth and r e l a t e d phenomena well, corroborative observational and experimental evidence has been obtained through work on laboratory animals l i k e mice, rats and r a b b i t s , e.g. Montagna ( 1 9 5 6 ) , Butcher ( 1 9 5 D , Chase ( 1 9 5 * 0 . C o l l i n s ( 1 9 1 8 ) , Dawson ( 1 9 3 0 ) , Hay and Praser ( 1 9 5 ^ , 1 9 5 5 ) , Dry ( 1 9 2 6 ) , etc. 2 . Domestic animals of economic Importance a) Sheep Since t h e i r wool i s of commercial significance, the phenome-non of wool production has been looked at i n some d e t a i l , e.g. Fraser and Short ( I 9 6 0 ) , Auber ( 1 9 5 2 ) , Carter and Clarke ( 1 9 5 7 ) , Hardy and Lyne ( 1 9 5 6 ) , Carter ( 1 9 3 9 , 1 9 ^ 3 . 1 9 5 5 ) , Duerden ( 1 9 2 7 , 1 9 2 9 ) , Duerden and Whitnall ( 1 9 3 0 ) , Ryder ( 1 9 5 7 , 1 9 5 8 ) , Wildman ( 1 9 3 2 , 1 9 5 7 ) , etc. b) Cattle The skin and pelage of c a t t l e have been investigated to some extent, p a r t i c u l a r l y because of i t s importance i n determining s u i t a b i l i t y for Introduction of temperate zone c a t t l e into areas 3 of hot climate, and also to a r r i v e at hybrids more suited to new environments, e.g. Carter and Dowllng ( 1 9 5 * 0 * Camek ( 1 9 2 0 ) , Dowling ( 1 9 5 5 , 1 9 5 8 , 1 9 5 9 ) . Bonsma ( 1 9 * * 3 . 1 9 5 * 0 , Yeates, N.T.M. ( 1 9 5 ^ , 1 9 5 5 ) , Dowling ( I 9 6 0 ) , Hayman ( 1 9 5 6 ) , Dowllng and Nay ( I 9 6 0 ) , Nay and Hayman ( 1 9 6 3 ) . Hayman and Nay ( 1 9 6 l ) , Schleger and burner ( i 9 6 0 ) . Most of the work has been done i n A u s t r a l i a . 3 « Animals with economically valuable p e l t s The pelts of these mammalian types are of commercial impor-tance. The phenomenon of hair growth has been investigated to some extent i n the following species, e.g. Lyne ( 1 9 5 6 ) on chin-c h i l l a , Dolnick ( 1 9 5 6 ) on mink, Scheffer ( 1 9 6 l ) , Rand ( 1 9 5 6 ) , Ling ( 1 9 6 5 ) on s e a l . As regards the r e s t of mammals very l i t t l e Is known. From what l i t e r a t u r e i s available the following are Interesting, De Meijer (189*0, Lyne ( 1 9 5 7 ) . Carter ( 1 9 6 5 ) . The knowledge gained on the biology of skin and hair growth, has been the subject of several reviews i n books, notably those of Hamilton ( 1 9 5 1 ) . Montagna ( 1 9 5 6 ) , Montagna and E l l i s ( 1 9 5 8 ) , Rook and Champion ( 1 9 6 2 ) , Lyne and Short ( 1 9 6 5 ) , Rothman ( 1 9 5 * 0 . Admittedly many of the contributors to the above lean heavily on data from medical dermatology — none the l e s s they are of relevance i n understanding skin and hair growth of mammals i n general. Studies on morphology of hairs are also Important. Hairs themselves present c h a r a c t e r i s t i c s of scutelation, i n t e r n a l structure and pigmentation that permit the I d e n t i f i c a t i o n of many mammalian higher taxa by t h i s means alone. Important contribu-tions i n t h i s respect are from Wildman ( 1 9 5 * 1 - ) . Appleyard ( i 9 6 0 ) , Spence (1963). Mayer (19^9), Stains (1958), and Day (1965). Apart from such studies of the h a i r f i b r e i t s e l f l i t t l e i s known about the c h a r a c t e r i s t i c s of the skin, pelage, and pelage cycle of w i l d species. The present study i s an attempt to provide information on these aspects of the biology of a single species of the large diverse and widely d i s t r i b u t e d family of ungulates — the cervidae, for which no detailed information i s a v a i l a b l e . 5 Chapter II THE CERVID PELAGE Exi s t i n g descriptions of cervld pelage are general and are more of use i n i d e n t i f i c a t i o n and description of the animal. Consequently many important facets have been overlooked. We have very l i m i t e d information on the types of hairs constituting the cervid pelage, t h e i r i n d i v i d u a l growth cycles, the patterns of moult, and the f o l l i c l e s i n which these hairs a r i s e . We also have l i t t l e information on the phylogenetic, adaptive and behav-i o u r a l signifance of the pelage. We do not know anything d e f i n i t e about the e f f e c t of environmental factors of the cervid pelage. Caton (I877) appears to be the f i r s t author to describe at some length the pelage c h a r a c t e r i s t i c s and trends of moult i n North American cervlds. Lydekker (I898) dealt with the cervid genera of the world Including a general description of the pelage. In introductory pages however there i s an i n t e r e s t i n g discussion of i t s adaptive and behaviourally s i g n i f i c a n t features. Murie (1951) and Peterson (1955) i n t h e i r works on elk and moose respectively touch upon some pelage c h a r a c t e r i s t i c s and aspects of moult. Llnsdale and Tomich (1953) also r e f e r to the coat and moult char-acters of the mule deer. They mention colouration and moult trends. Severinghaus and Chaetum i n Taylor (1956), discuss adult coat and moult i n the white t a i l e d deer — Odocolleus vlrglnlanus and quote i n d e t a i l from Caton (I877). In the same volume mate-r i a l r e l a t i n g to the Columbian black t a i l deer Odocolleus hemlonus 6 columblanus (Richardson), i s contributed by Cowan (1956); who offers a succinct summary of pelage features and moult. Apart from Lydekker (I898) the only other authoritative contribution dealing with cervid forms over the world i s by Plerov (i960). Here the emphasis i s more on the palaearctic forms; the material on North American forms being scanty. The s a l i e n t features of cervid pelage as they emerge from the above contributions can be b r i e f l y summarized as follows: The hairs on the body vary i n length. Those on the dorsal side are normally longer than those on the ventral side. Simi-l a r l y there i s an increase i n length from anterior to posterior. Some regions of the body bear s p e c i a l i z e d h a i r s . In general hairs i n the a x i l l a , lnguinum, rump and t a l l are longer whereas those on face, ears, and extremities of legs are shorter. Also hairs on the under part are softer and paler than those on the exposed body surface. The pelage generally consists of an overcoat and an under-coat. The overcoat i s made of hairs which are longer and thicker than those of the undercoat. They have c h a r a c t e r i s t i c colour-a t i o n — a n d t h e i r d i s t a l extremity i s mostly responsible for giving the animal i t s colouration. The guard hairs constitute the outercoat and the bulk of the pelage. In c e r t a i n cervid forms l i k e Dama Elaphorus, Capreolus (Flerov i960), a sp e c i a l type of guard hair — occurring uniformly scattered over the body about 2.5 cms. apart — and having almost double the length of normal guard hairs — h a s been recorded. These may be t a c t i l e i n function* The undercoat consists of woolly h a i r s , which are wavy, smaller In diameter reaching on maturity about three fourths of 7 the length of guard h a i r s . These are not v i s i b l e externally and are present i n bulk only i n cervid winter coat. However i n genus Busa and sub-genus Przewalskium these hairs are absent i n the winter coat (Flerov i960 ) . The significance of t h i s i s discussed subsequently. In the course of the year the cerv i d pelage has two phases. The summer phase i s of l i g h t e r colour and marked by s c a r c i t y of woolly under h a i r s . The winter phase i s darker coloured and has an abundance of woolly under h a i r s . The change over from one phase Into the other i s brought about by a process of moulting, involving shedding of old hairs accompanied by growth of new h a i r s . Flerov (i960) discusses aspects of t h i s process i n some d e t a i l . The two main features i n the evolution of cervid pelage that a t t r a c t immediate attention are: 1 ) Primitive forms with spotted pelage that i n the advanced forms occurs only i n the newborn or not at a l l . 2) Evolution of a winter coat s p e c i f i c a l l y adapted to meet rigours of cold environment. These w i l l be considered i n t h e i r respective order. The spotted nature of the coat i s said to be of protective value. By helping to break up the body outline i t merges the animal with the patterns of l i g h t as they exist i n forests, and e f f e c t i v e l y conceals i t . The spotted coat i s present throughout the l i f e of c e r t a i n cervid forms e.g. Axis axis, or i t may be present only i n the fawn b i r t h coat and adult summer coat — being very weak or absent i n the adult winter coat. e.g. Cervus nlppon the Japanese Sika deer. In the r e l a t i v e l y recent forms l i k e Odoooileus the spots 8 are retained only i n b i r t h coat, Caton (I878) however refe r s to f a i n t spots exhibited i n summer coat of some Odooolleus Virginia:- nus forms. Cowan (1965) states that only the fawn "black t a i l " O are spotted and that these spots disappear with loss of the fawns hiding i n s t i n c t i n the f i e l d . Also recent forms l i k e Cervus  canadensis and Alee alces have fawns and adults devoid of any spots on the pelage. There i s thus a d e f i n i t e evolutionary trend towards loss of spots, the reason f o r which i s not c l e a r . The evolution of a thick winter coat i s also i n t e r e s t i n g . It i s generally assumed that deer f i r s t evolved i n warm t r o p i c a l forests and possessed a brownish coat equivalent of present day cervid summer coat. This coat, i n addition, was spotted along the flanks, Lydekker (I898). The present day summer coat i s reminiscent of i t . With the gradual spread of cervid forms to areas of colder climate the need f o r a winter coat arose and factors leading towards i t appear to have been selected f o r , these consist of development of woolly undercoat and thicker guard h a i r s . Such a heavy coat however i s a l i a b i l i t y i n summer and thus the process of moulting twice a year has been selected f o r by which appropriate coats (summer and winter) are assumed during 0 the course of the year In consonance with the season. The sub genus Przewalsklum a cervine form occurring i n cold Tibetan highlands i s int e r e s t i n g i n t h i s respect. Though i t possesses a winter and summer coat, i t s winter coat i s devoid of woolly underhair Flerov (i960). Instead i t s winter coat i s con-s t i t u t e d of ha i r s which are long and twice as thick as the summer h a i r s . There are thus at lea s t two d i f f e r e n t evolutionary routes to development of winter adapted pelage. 9 When only one type of coat was present presumably the moult ing took place only once a year replacing a coat affected by normal wear and tear during the year. With two types of coat — two moults a year were necessary. Males generally are f i r s t to moult and fawns and unbred females follow. Females with fawn generally moult a month or so l a t e r . S u f f i c i e n t l y d etailed i n f o r matlon on cervid patterns of moult i s not available — nor the sequence i n which various hair types are shed. Flerov (I960) also r e f e r s to the occurrence of whorls i n pelage of many cerv i d form e.g. Przewalsklum, Elaphorus, Dama, Mazama, etc. The se l e c t i o n value of these s t r u c t u r a l oddities i s not cl e a r . P a r n e l l (1951) discusses the basis for these whorls i n two main types. a) "factors influencing growth of embryo such as tension and pressure of th i n surface, i t s thickness and pressure or absence of the structure beneath i t " . b) " i n t r i n s i c factors i n growing hair germ such as a physiological gradient or i n the genetical make up of the i n d i v i d u a l " . Behaviourally cervid pelage presents i n t e r e s t i n g features. The increased growth of hair on the neck leading, to the forma-t i o n of a mane, p a r t i c u l a r l y i n breeding season, i s believed to be of protective and display value, as at t h i s time combats are frequent. The underside of the t a i l , as well as the posterior margin of thighs i s generally white (Odocolleus, Ax i s ) . When excited as when f l e e i n g , such forms r a i s e t h e i r t a i l s , and i t s white underside i n conjunction with white posterior margins of thigh forms a very noticeable white area — e n a b l i n g animals to follow 10 each other. In Axis and Odocolleus the white hairs of t h i s region are e r e c t i l e . In forms l i k e Capreolus and Cervus, a white rump patch i s formed; for Capreolus t h i s i s only i n the winter coat. In species having a rump patch the t a i l i s reduced and i s not rais e d when the animals are excited or f l e e i n g . The hairs surrounding the t a r s a l and metatarsal glands are much coarser than the adjoining hairs and are capable of erection. Though not a part of the pelage the 'velvet* covering the antlers of deer i s also of great i n t e r e s t . I t bears short and soft hairs a r i s i n g i n f o l l i c l e s which lack the sweat gland and the A. p l l i i muscle. When the antlers mature the velvet becomes necrotic and i s shed; only to be formed again »de novo' to cover a new set of growing a n t l e r s , the following year. This i s the only case of hair f o l l i c l e neogenesis i n adult mammals supported by i r r e f u t a b l e evidence, Blllingham (1958) . 11 Chapter III PRENATAL DEVELOPMENT OF THE PILARY SYSTEM IN DEER INTRODUCTION Though intere s t i n the general phenomenon of hair growth i s increasing, observations on prenatal development of hair f o l l i c l e s are r e l a t e d structures continues to be l i m i t e d . Known examples of s i g n i f i c a n t work done i n the f i e l d are guinea pig, (Seagall 1 9 1 8 ) ; mouse,(Hardy, 1 9 ^ 9 ) ; bandicoot (Lyne, 1957); mink (Dolnick 1959); c a t t l e (Lyne and Heideman, 1959. I 9 6 0 ) ; sheep (Wildman, 1932 and Hardy and Lyne, 1956); goat (Margolena, 1959); and elephant seal (Ling, 1965) . In general these workers have traced the development of hair f o l l i c l e s and suggested boundaries and c r i t e r i a of a u s e f u l approach to standardize stages, In the continuous process. No study of f o l l i c l e development appears to have been made i n wild ungulates. The present work reports the course of devel-opment of the p i l a r y system i n the black t a i l deer Odocolleus  hemionus columbianus (Richardson), a North American cervid, and thus provides f o r the f i r s t time a basis for comparison between two of the major families of the a r t i o d a c t y l a — the cervidae and the bovidae. MATERIALS AND METHODS This study i s based upon a series of foetuses taken from wild does c o l l e c t e d i n the course of a study of reproduction i n t h i s species. Preservation was i n formol s a l i n e . 12 TABLE 1 Basic Data on Foetuses Sampled Foetus Numbers* Date Forehead Rump Length (mm) T 8 0 A M* 15 Jan. 65 4 6 . 2 T27 p# 29 Jan. 64 8 9 . 5 T36 p# 3 Feb. 64 112 .5 T4-1 A M* 19 March 64 1 8 1 . 5 T46 B M* 22 March 64 2 0 2 . 0 T5^ M* 6 May- 64 211 .5 T40 A M* 1 8 Mar ch 64 2 3 5 . 0 T56 A M* 7 May 6k 2 3 6 . 0 M l p* 8 A p r i l 63 2 6 9 . 0 T 8 2 M* 16 A p r i l 66 2 8 7 . 0 T63 A F* 11 May 6^ 3 2 1 . 0-L T60 B M* 11 May 64 3 3 5 . 0 T 6 6 p# 13 May 64 3 6 6 . 0 T69 M* 12 June 64 4-22.0 T70 A M* 12 June 64 438 mm *f= Female *m= Male 13 F i f t e e n representative foetuses each of a d i f f e r e n t devel-opmental stage were selected f o r sampling purposes. A l l but one i . e . (M]_) were from Northwest Bay, Vancouver Island, B.C. Skin samples were taken from each at predetermined locations, d o r s a l l y on the base of the neck. The material so obtained was h i s t o l o g i c a l l y processed (see Appendix I) and 8 thick sections were cut p a r a l l e l to the skin surface as well as across i t . These were stained i n Haematoxylin and Eosln and used f o r further observations. OBSERVATIONS The development of hair f o l l i c l e s can be studied i n two main aspects namely the development of the i n d i v i d u a l hair f o l l i -c l e — and the development of the f o l l i c l e groups and population. In the ungulates investigations of t h i s aspect appear to be r e s t r i c t e d to sheep and c a t t l e . Wildman (1932) has discussed the prenatal development of a wool f o l l i c l e i n some of the B r i t i s h breeds of sheep. Hardy and Lyne (1956)have charted development of merino f o l l i c l e s and pro-posed recognition of eight developmental stages, the f i n a l stage of which i s reached when the hair emerges on the skin surface. Lyne and Heideman (1959) i n course of t h e i r work on f o l l i c l e development i n c a t t l e have proposed ten stages rather than eight, the f i n a l stage being reached when the hair growth ceases and the f o l l i c l e r e s t s . These stages of f o l l i c l e development have proved applicable to those species investigated to date and provide a useful framework f o r the study of other species. They can be stated as follows (Fig. 1) Ih K E R A T I N I Z E D H A I R M E D U L L A mA I N N E R R O O T S H E A T H S E B A C E O U S C E L L S P R E - P A P I L L A FIG. I STAGES I TO 10 IN THE DEVELOPMENT OF MAMMALIAN HAIR FOLLICLES AS SHOWN IN CATTLE AFTER LYNE AND HE IDEMAN (1959) Stage I. F o l l i c l e plug This i s divided into two stages. a) when length of plug i s less than i t s diameter. b) when length i s equal to or greater than diameter. Stage 2. Pre - p a p i l l a a) F o l l i c l e length more than twice i t s diameter, the base of epidermal plug flattened, sweat gland appears at higher l e v e l s of f o l l i c l e i n form of a s o l i d bud located on ental side. b) F i r s t trace of arrector p i l i i muscle now appears i n dermis; A swelling i s also noticed halfway down on ental side of f o l l i c l e . This i s the ental swelling. Sebaceous c e l l s begin to d i f f e r e n t i a t e below junction of sweat gland and constitute rudiments of sebaceous gland. F i r s t stages of h a i r canal formation noticed. Stage 3. P a p i l l a The d i f f e r e n t i a t i o n of sub stages here i s based on the shape of the dermal p a p i l l a . a) F o l l i c l e base becomes concave and dermal p a p i l l a i s greater i n diameter than i n depth. Arrector p i l i i muscle extends from upper part of dermis up to ental swelling. Hair canal formation i s noted. Sweat gland has now reached i n depth the region between ental swelling and bulb of f o l l i c l e , and contains a lumen at i t s d i s t a l end. b) Length of dermal p a p i l l a equal or greater than i t s diameter. Ental swelling has reached maximum size and hair canal development i s almost complete and i t s part i n epidermis i s l y i n g almost p a r a l l e l to skin surface. Stage 4. Hair cone The ental swelling now becomes a l i t t l e l e s s prominent and the deeper end of the f o l l i c l e exhibits the presence of a hair cone. Stage 5• Advanced hair cone The t i p of h a i r cone Is r e t r a c t i l e . Stage 6. Hair formation Hair cone l i e s at about l e v e l of sebaceous gland. Hair t i p i s kerat i n i s e d . A l l f o l l i c l e layers are by now formed. Stage 7. Hair In canal Tip of the hair has emerged into hair canal. Stage 8. Hair emerged Hair has emerged on surface. Stage 9 • End of f o l l i c l e growth F o l l i c l e reaches i t s maximum growth. Stage 10. Club hair formation a) Bulb contracts and connective tissue around i t gets c r i n k l e d . b) Club hair formulation with t y p i c a l brush end i s f i r s t recognised. c) Club hair i s keratinised i n f u l l . In stage ten the formation of the medulla comes to an end followed l a t e r by the hair c u t i c l e and the inner root sheath. The f o l l i c l e i s simultaneously decreasing i n length and the bulb and dermal p a p i l l a undergo degeneration t i l l they somewhat resemble t h e i r morphology i n stage three. It must be noticed that these stages r e f e r to the devel-opment of i n d i v i d u a l hair f o l l i c l e s and not the f o l l i c l e popula-t i o n . A l l the above stages, can be i d e n t i f i e d i n the sequence of development of f o l l i c l e s i n Odocolleus. There are minor v a r i a -tions and these w i l l be detailed l a t e r . Another aspect of f o l l i c l e development i s that of the o r i g i n of groups and populations of f o l l i c l e s . Different 1 7 categories of f o l l i c l e s a r i s e that give o r i g i n to hairs of d i s t i n c t types. Furthermore the arrangement and spacing of f o l l i -c les present features that may be of importance i n the elucidation of systematic positions or ecological adaptation. De Meijere ( 1 8 9 * 0 was one of the f i r s t to investigate arrangement of hair f o l l i c l e s and the hair a r i s i n g i n them. His work stands out as a pioneering c l a s s i c of i t s kind, i n which he brought out the f a c t that b a s i c a l l y the f i r s t formed f o l l i c l e s i n mammals are arranged i n groups of three of which the central f o l l i c l e i s larger than the two f o l l i c l e s l y i n g l a t e r a l to i t . The hair f o l l i c l e s have also been c l a s s i f i e d i n r e l a t i o n to t h e i r sequence of o r i g i n and development. Noback ( 1 9 5 1 ) has discussed t h i s succinctly as follows: "The f i r s t f o l l i c l e s to d i f f e r e n t i a t e are the central t r i o f o l l i c l e s . I f these f o l l i c l e s appear at two d i f f e r e n t times as i n opossum (Gibbs 1 9 3 8 ) , then the f o l l i c l e s are c a l l e d "primary X" and "primary Y". The es s e n t i a l point i s that each of these primary f o l l i c l e s w i l l be the cen t r a l f o l l i c l e s of d i f f e r e n t groups. Later i n development other f o l l i c l e s of the hair group d i f f e r e n t i a t e i n r e l a t i o n to these c e n t r a l t r i o f o l l i c l e s . The t r i o i s formed when two f o l l i c l e s are d i f f e r e n t i a t e d l a t e r a l to the primary f o l l i c l e s . The l a t e r a l f o l l i c l e s associated with "primary x" or "primary Y" are c a l l e d respectively "primary 3£ or primary Y " . I f only one l a t e r a l f o l l i c l e i s formed adjacent to a primary f o l l i c l e (X or Y) then a couplet f o l l i c l e i s formed. If no l a t e r a l f o l l i c l e s d i f f e r e n t i a t e a primary (X or Y) i s c a l l e d s o l i t a r y f o l l i c l e . Later another generation of f o l l i c l e s i s d i f f e r e n t i a t e d — the secondary f o l l i c l e s . In the opossum these f o l l i c l e s are located between the cen t r a l t r i o f o l l i c l e and the 18 l a t e r a l t r i o f o l l i c l e . The ontogenetic studies of f o l l i c l e arrangement have added confirmatory evidence to De Meijere's basic concept that i n mammals there i s a universal and regular grouping of hair f o l l i c l e s . (Hardy 194-6)" . F o l l i c l e and Hair development The hair f o l l i c l e s of the black t a i l deer can be divided on the basis of t h e i r o r i g i n into two types — the primary and the secondary. The primaries are the f i r s t to form and develop i n groups of three ( t r i o grouping), of these the central f o l l i c l e of the t r i o i s the f i r s t to form — a n d Is akin to "primary X". The l a t e r formed primaries which form the two l a t e r a l f o l l i c l e s of t r i o grouping are akin to "primary X" of Noback (1951)• There i s no occurrence of "primary *Y'" f o l l i c l e s nor any of 'primary Y' types. Each of the primaries possesses a sweat gland, sebaceous gland and arrector p l l i l muscle. In contrast to the primaries which s t a r t developing around 112 mm. stage, the secondary f o l l i -c l e s begin developing around 269 mm. stage. The secondary f o l l i -c l e s are much smaller than the primaries and are located In groups between the primaries. The f i r s t formed secondaries are larger than those subsequently formed and possess sweat gland, sebaceous gland and arrector p i l l i muscle. The res t of the secondaries bear only sebaceous gland and the smaller of them may even lack these. The f o l l i c l e types bear a close r e l a t i o n s h i p to the hairs that are produced i n them. We know that the black t a i l pelage consists of an overcoat and a woolly undercoat which i s well developed during winter. The overcoat consists of hairs produced FIGURE 2 Grouping of primary and secondary f o l l i c l e s i n deer. Transverse section. Notice the t y p i c a l ' f i v e ' grouping; of primary and secondary f o l l i -c l e s . H.& E. FIGURE 3A Deer primary f o l l i c l e . Longitudinal section. General view of the lower end of the f o l l i c l e . Notice well developed medulla. H. & E. FIGURE 3B Deer secondary f o l l i c l e . Longitudinal section. General view of the lower end of the f o l l i c l e . Notice hyaline membrane on both sides of ext. rooth sheath and absence of the medulla. H. & E. FIGURE 4.1 Developing skin and hair f o l l i c l e s . 112 mm. stage. Longitudinal section. Notice the t h i n epidermis and the hair f o l l i c l e anlage being formed. H. & E. For explanation of abbreviations used please see Appendix IV,' Page 214. 2 0 21 i n primary f o l l i c l e s . Some of these are almost double the length of the other overcoat hairs and are scattered on the body about 2.5 cms. apart. I have referre d to them as the large guard h a i r s . They are produced by some of the central primary f o l l i c l e s . The re s t of the central primary f o l l i c l e s and a l l of the l a t e r a l primary f o l l i c l e s give r i s e to what I c a l l intermediate guard h a i r s . These constitute the r e s t of the overcoat. Of course there i s a good deal of v a r i a t i o n i n size of the intermediate guard hairs but consistently i n a t r i o those produced i n the central primaries are larger than those produced by the l a t e r a l primaries. A l l the hairs produced by primary f o l l i c l e s are medullated. The black t a i l e d fawns are characterized by possession of white spots on t h e i r body. These are formed by the occurrence i n these s i t e s of ha i r possessing white d i s t a l extremities. These hairs appear to be produced mostly i n central primary f o l l i c l e s and some i n l a t e r a l primaries. The white tipped part has a greater development of the cortex and a medulla devoid of i n t r a -c e l l u l a r c a v i t i e s . In subsequent hair cycles these hairs are replaced by normal outercoat h a i r s . This phenomenon by which a hair f o l l i c l e produces one type of hair at one stage and another type at a d i f f e r e n t stage i s not unusual. Wlldman (1927), reports t h i s occurring i n some sheep, including f i n e wooled merino. The secondary f o l l i c l e s of the black t a i l deer give r i s e to the undercoat. This i s not v i s i b l e externally but i s woolly and i s pronouncedly developed i n the animal's winter coat. I t i s int e r e s t i n g and important to note that the f i r s t formed secondary f o l l i c l e s produce medullated h a i r s , whereas the r e s t of the 22 secondaries produce non medullated h a i r s . The bulk of the under-coat consists of the l a t t e r . In the course of t h i s study I have also c l a s s i f i e d f o l l i c l e s on the basis of hair types produced by them. This makes the study of t h e i r i n d i v i d u a l development easier. The c l a s s i f i c a t i o n i s as follows: a) Large guard hair f o l l i c l e s . These are some of the central primaries producing large guard h a i r s . b) Central intermediate guard hair f o l l i c l e s . These are the r e s t of the central primaries, which produce intermediate guard h a i r s . The hairs produced by them are longer and larger than those produced by l a t e r a l intermediate guard hair f o l l i c l e s i . e . l a t e r a l primaries. c) L a t e r a l intermediate guard hair f o l l i c l e s . They are the same as the l a t e r a l primaries and produce intermediate guard hair f o l l i c l e s . d) F i r s t formed secondary f o l l i c l e s . These are larger than the l a t e r formed and produce medullated h a i r s . These f o l l i c l e s l i k e the primaries possess sweat gland, sebaceous gland and arrector p i l i i muscle. e) Later formed secondary f o l l i c l e s . These are small. Possess only sebaceous glands (the smallest may even lack these) and produce non medullated woolly underhair — constituting the bulk of the undercoat. At t h i s stage i t should be noted that i n the fawn b i r t h coat some of the cen t r a l primaries and l a t e r a l primaries give r i s e to guard hairs with white t i p s . These hairs are character-ized by greater thickness of the cortex, and by possessing a 23 medulla devoid of i n t r a c e l l u l a r c a v i t i e s , so c h a r a c t e r i s t i c of the medulla of other overcoat h a i r s . On the other hand the medullary c e l l s appear to be f u l l of droplets — perhaps of t r i c h o -hyaline. The observations on f o l l i c l e development that I have been able to make are as follows: The general mammalian stages of f o l l i c l e development are noticed i n the black t a i l deer. However variations from the normal have been documented i n a number of places. 0 Large guard hair f o l l i c l e s These are the e a r l i e s t f o l l i c l e s to develop and can be i d e n t i f i e d by t h e i r greater depth of penetration into the dermis. Where present they constitute the central f o l l i c l e of the primary t r i o grouping. These f o l l i c l e s give r i s e to the large guard h a i r s . They are beginning development i n a 112 mm. foetus; are a c t i v e l y producing hair i n a new born fawn, and are generally-r e s t i n g In a f i v e week fawn. They possess sweat gland, sebaceous gland, and arrector p i l i i muscle. The external root sheath i s well developed and prominently nucleated. The f o l l i c l e bulb i s large and oval. The inner root sheath i s also prominent — p a r t i c -u l a r l y the Henle's layer. Compared to the size of the f o l l i c l e the sebaceous gland i s small. Just below the junction of the sebaceous gland the f o l l i c l e appears to d i l a t e i n the form of a bulbous cavity, the l i n i n g of which (made of inner root sheath) has a folded appearance. These " f o l l i c u l a r f o l d s " are supposed to be part of the break down of the inner root sheath and have also been noticed i n case of the common amer lean goat, Sar Developing skin and hair f o l l i c l e s . 202 mm stage FIGURE 5.1 The epidermis has increased i n size and periderm i s d i s t i n c t . The sweat gland i s developing and f o l l i c l e base i s half enveloping the dermal p a p i l l a . The fibrous deposition i n dermis i s also noticed. H. & E. FIGURE 5.2 Transverse section of above. Notice sweat gland developing adjoining the h a i r f o l l i c l e • H. & E. Developing skin and hair f o l l i c l e . 235 nun stage. FIGURE 6 .1 Longitudinal section. Notice well developed stratum spinosum. Periderm i s peeling and below i t granular layer (stratum granulosum) i s forming. Sweat gland has no lumen. Sebaceous gland and h a i r canal formation i s also present. Dermis i s more compact. Rudimentary arrector p i l i i development i s seen. H. & E. FIGURE 6.2 Transverse section of above. Sweat gland f o l l i c l e r e l a t i o n s h i p i s seen. H. & E. For explanation of abbrevations used please see Appendix IV, Page 21k% 2 5 Developing skin and hair f o l l i c l e s . 269 mm stage FIGURE 7.1 Longitudinal section. Notice the compact epidermis and the d i s t i n c t i v e stratum corneum. Sebaceous gland i s d i s t i n c t i v e so also i t s po s i t i o n v i s a v i s sweat gland. Dermis more compact and f i b r o u s . Ental swelling and arrector p i l i i muscle present. Hi & E. FIGURE 7.2 Transverse section of above. Large guard h a i r f o l l i c l e d i s t i n c t with h a i r . Sweat gland and bilobed sebaceous gland seen. F i r s t formed secondaries developing. H. & E. Developing skin and hair f o l l i c l e s . 28? mm stage. FIGURE 8.1 Longitudinal section. White tipped h a i r f o l l i c l e s c l e a r l y seen. Secondary f o l l i c l e s forming. H. & E. FIGURE 8.2 Transverse section of above. Central primaries have larger hairs than l a t e r a l primaries. H. & E. For explanation of abbreviations used please see Appendix IV. Page 214. 27 Developing skin and hair f o l l i c l e s . 321 mm stage FIGURE 9.2 Longitudinal section. Notice size r e l a t i o n -ship of central primary to l a t e r formed secon-daries s t i l l forming. H. & Et FIGURE 9.2 Transverse section of above. H. & E. Developing skin and hair f o l l i c l e s . 448 mm stage FIGURE 10.1 Longitudinal section. General view. H. & E. FIGURE 10.2 Transverse section of above. Notice white tipped hair f o l l i c l e s i n section. H. & E. For explanation of abbreviations used please see Appendix IV, Page 214-. 29 Large guard f o l l i c l e . 287 mm stage FIGURE 11.1 Longitudinal section. Notice large size of large guard hair f o l l i c l e v i s a v i s other types and well developed external root sheath. H. & E. FIGURE 11.2 Transverse section of above. Notice f o l l i c l e arrangement. H. & E. FIGURE 11.3 Longitudinal section. Close up of d i l a t e d upper part of large guard hair f o l l i c l e and hair passing through i t . Dermis i s very compact now. H.&E-. FIGURE 11.4 Longitudinal section. Close up of the f o l l i c l e bulb. Notice heavy melanin,deposition i n f o l l i c l e and well developed external root sheath. H. & E. For explanation of abbreviations used please see Appendix IV, Page 214. Fib SwG Ap FIG It.4 32 and Calhoun (1966). I t i s pertinent to remark that the species studied by these authors i s not known as they have used a meaningless name. With the exception of Flerov (I960), who r e f e r s to occur-rence of large guard hairs i n the cervid genera Dama, Capreolus, and Elaphorus, no reference has been made to occurrences of such hairs or the large guard hair f o l l i c l e s i n the ungulates. S t r a i l e (i960) discusses the occurrence of t y l o t r i c h i n mammals (Mice, Rats and Rabbits) and th e i r function. The t y l o t r i c h s are much larger than the surrounding guard hairs and are sparsely d i s t r i b u t e d . They are sensory hair types a r i s i n g i n f o l l i c l e s which possess, amongst other things, an "Annular complex" consis-ti n g of connective tissue, c a p i l l a r i e s and nerve endings, surrounding the f o l l i c l e below the l e v e l of sebaceous gland. The o r i f i c e of the f o l l i c l e i s also characterized by possession of a spec i a l thickened area of the epidermis c a l l e d "Baarschlebe" surrounding the o r i f i c e . The t y l o t r i c h f o l l i c l e i s sensory and i s intermediate i n size between the v i b r i s s a f o l l i c l e and the normal hair f o l l i c l e . In the l i v i n g adult Odooolleus the large guard hairs are scattered over the body and are prominently longer than other outercoat h a i r s . If they are touched i n the l i v i n g animal the skin i s twitched i n response. This i s not true with the hairs of other types. Thus the large guard hair f o l l i c l e s appear "prima f a c i e " to be possessed of greater sensory function than normal h a i r s . In Odooolleus they s t a r t development s l i g h t l y e a r l i e r than other primary f o l l i c l e s but grow to much greater length because of greater rate of growth during the f o l l i c l e development, and a longer hair growth period. Their upper part was 33 occasionaly d i l a t e d . The hairs produced by them are the f i r s t to emerge on the surface. No d i s t i n c t i v e "Annular complex" or "Haarschiebe" have been detected i n t y l o t r i c h f o l l i c l e s of Odocolleus. The developmental stages undergone, as observed (Table II) are s imilar to the standard mammalian stages (Lyne and Heideman, 1959) but owing to faster rate of embryonic growth are a stage or two ahead of other c e n t r a l primaries. They d i f f e r i n some anatom-i c a l features already discussed and i n the longer period of hair growth — t h u s they are the f i r s t to r i s e and l a s t to come to r e s t . A l l i n a l l the present evidence suggests that 'the large guard f o l l i c l e s of Odocolleus, though morphologically a l i t t l e d i f f e r e n t , are developmentally and f u n c t i o n a l l y r e l a t e d to t y l o t r i c h s of S t r a i l e ( i960) . The Intermediate guard hair f o l l i c l e The overwhelming majority of f o l l i c l e s giving r i s e to the overcoat of Odooolleus belong to t h i s category. They consist of ce n t r a l primaries ( i . e . a l l other than these giving r i s e to large guard hairs) and a l l the l a t e r a l primaries. The l a t e r a l primaries are smaller i n size than the central primaries and the difference i s also r e f l e c t e d i n the hairs produced. Due to r e l a t i v e abundance of t h i s type of f o l l i c l e — t h e i r development has been studied i n greater d e t a i l , p a r t i c u l a r l y so i n case of c e n t r a l primaries because of t h e i r large s i z e . TABLE II F o l l i c l e types and t h e i r development stages B D No. Forehead Rump E Central primary Large guard hairs Central primary Intermediate L a t e r a l primary Intermediate F i r s t formed Secondary Length Guard hairs Guard hairs T 8 0 A 4 - 6 . 2 T 2 ? 8 9 . 5 T 3 6 1 1 2 . 0 1A* 1A 1A T4-1A 181.5 2B 2B 2A T4-6B 2 0 2 . 0 2B 2B 2 A T 5 4 2 1 1 . 5 3 A - 3 B 2 B - 3 A 2B T4-0A 2 3 5 . 0 3B-4- 3B-3A 2B-3A T 5 6 A 2 3 6 . 0 4 - 5 4- 3B » 1 2 6 9 . 5 6 , 7 , 8 5 - 6 k 1 A - 2 A T 8 2 287 .0 8 8 7 - 8 3 a - 3 B T 6 3 A 3 2 1 . 0 8 8 8 8 516 O B 3 3 5 . 0 8 8 8 T66 3 6 6 . 0 8 8 8 T69 4-22.0 8 8 8 T 7 0 A 4-4 - 8 . 0 9 9 9 9 Fawn 5 weeks 10B-10C 10B-10C 10B-10C 1 0 C Later formed Secondary la-2A S t i l l forming *Details of stages given on pp 1 5 - 1 6 35 Central Intermediate guard hair f o l l i c l e s (central primary type) A 112 mm foetus shows these f o l l i c l e s i n stage l a . The developing f o l l i c l e anlagen are located at i n t e r v a l s of approxi-mately 250/^ to 294 . At t h i s stage the diameter of t h i s p a p i l l a i s greater than i t s depth. These anlagen are formed "by the p r o l i f e r a t i v e a c t i v i t y of the basal layer of epidermis and make indentation i n the dermo-epidermal Junction. They are about 70/*- wide and 16/*- i n depth. The dermal elements also are more t h i c k l y located below these anlagen — thus the association of dermal elements with the hair f o l l i c l e starts very early. By 181 mm stage the f o l l i c l e s have reached the pr e p a p i l l a stage i . e . Is stage 2b. The growing f o l l i c l e s appear as rods of undifferentiated c e l l s , enclosed i n an organized c e l l layer of one c e l l thickness. The d i s t a l end of these growing f o l l i c l e s i s marked by the presence of a mass of c e l l s of dermal o r i g i n . These l a t t e r constitute the dermal p a p i l l a of the growing f o l l i c l e s . In a d d i t i o n to t h i s a sheath of dermal o r i g i n covers the growing hair f o l l i c l e and the dermal p a p i l l a . This i s akin to the connec-t i v e tissue sheath of the mature f o l l i c l e . The dermal p a p i l l a at t h i s stage i s 16/*- deep while the f o l l i c l e depth varies from 150/^ to 117A At 236 mm stage the f o l l i c l e s have reached stages varying from 3b to 4-. The base of the f o l l i c l e has begun to envelop the dermal p a p i l l a . The ental swelling i s present there. The depth of f o l l i c l e penetration i s 226/*- to 2 3 5 • At 269 mm stage the f o l l i c l e s are i n stages 5 to 6 and have reached depths from 252 to 2 6 8 ^ . At 287 mm stage a l l f o l l i c l e s of t h i s type have reached Central intermediate guard hair f o l l i c l e s FIGURE 12.1 Longitudinal section. H.& E. FIGURE 12.2 Transverse section. Notice sweat gland and sebaceous r e l a t i o n s h i p and arrector p l l i i muscle. H. & E. White tipped hair f o l l i c l e s and l a t e r a l inter mediate guard hair f o l l i c l e s FIGURE 13.1 Longitudinal section white tipped h a i r . Notice greater development of cortex. H. & E. FIGURE 13.2 Transverse section. Notice greater development of external root sheath i n large guard h a i r . In white tipped hairs cortex i s better developed. H. & E. For explanation of abbreviations used please see Appendix IV, Page 2Ik. 37 Ap FIG 13. I FIG 13. 2 38 stage 8 i . e . hair emerged. These f o l l i c l e s are s t i l l growing h a i r a c t i v e l y when the fawn i s born, i . e . 448 mm stage (about) and stage nine i s not reached u n t i l few weeks a f t e r b i r t h . L a t e r a l intermediate guard h a i r f o l l i c l e s ( l a t e r a l primaries) These resemble the c e n t r a l intermediate guard hair f o l l i -c l e s i n a l l major respects — but are smaller i n s i z e . They are i n i t i a t e d a l i t t l e l a t e r than the central primaries, and consequently lag behind 2 to 3 stages i n development. For example i n 287 nun stage the central intermediate guard hair f o l l i c l e s have reached stage 8 i . e . hair emerged, the l a t e r a l intermediate guard hair f o l l i c l e s appear to be In stages varying from 5 to 4, as noticed from Table I I . At t h i s stage one would r e c o l l e c t that the fawn b i r t h coat has white spots — caused by white tipped hairs occurring i n that region. These are intermediate guard hairs a r i s i n g i n some of the c e n t r a l primaries and l a t e r a l primaries. Anatomically the f o l l i c l e s i n which they a r i s e are s i m i l a r to the other i n t e r -mediate guard hair f o l l i c l e s — except i n the following: a) The dermal p a p i l l a has a pointed apex and i s not of the normal spatulate type. b) The cortex i s two to three times thicker than i n the normal intermediate guard h a i r . c) The medulla i s made up of c e l l s which are f i l l e d with granular (trichohyalin) deposits. No i n t r a c e l l u l a r c a v i t i e s are formed. These c e l l s are reminlnscent of normal medullary c e l l s at a stage Just p r i o r to formation of i n t r a c e l l u l a r c a v i t i e s . It would thus appear that i n white tipped hairs the formation of i n t r a c e l l u l a r medullary c a v i t i e s i s arrested. d) Melanocytes are present i n the f o l l i c l e s — a n d they are confined to the c o r t i c a l region. The portion of cortex above the bulb appears dark — but subsequently the pigmentation d i l u t e s and the cortex appears, whitish-yellow. 39 In many mammals hair i s not uniformly coloured but i t has a terminal or subterminal band containing pheomelanin, and the base has melanin (agouti pattern). The white tipped hairs of Odocolleus, as well the winter coat guard hairs are of t h i s type. In bicoloured hairs each f o l l i c l e secretes a l l the pigments, occurring i n a hair, the type of pigment secreted varying with stage of hair growth cycle. Systemic conditions may a l t e r the in t e n s i t y of the pigment present i n any l o c a l i t y . ."Pltzpatrlck et a l ( 1 9 5 8 ) . In biochemical a c t i v i t y i n r e l a t i o n to pigment i s thus d i f f e r e n t i n white tipped hair and the v a r i a t i o n i n thi s a c t i v i t y i n r e l a t i o n to the f o l l i c l e producing pigmented hairs i s an int e r e s t i n g biochemical problem i n i t s e l f . Woolly under hair f o l l i c l e s (secondary f o l l i c l e s ) These are secondary f o l l i c l e s and are of two types, the f i r s t formed — possessing sweat gland, sebaceous gland, arrector p i l i i muscle and producing a small but medullated h a i r , and the l a t e r formed possessing only sebaceous gland and producing a non medullated woolly-type h a i r . The f o l l i c l e s of f i r s t type are f u l l y formed and have emergent hairs prenatally. Those of the second type continue to from prenatally as well as postnatally — and become f u l l y functional and e f f e c t i v e i n the fawn winter coat. As the material investigated i s prenatal my emphasis i s on development of f i r s t formed secondary f o l l i c l e s . In a 269 mm foetus these a r i s e s i n g l y . They are the f i r s t formed woolly f o l l i c l e s and are i n developmental stage l a to 2 a . In 287 mm stage the f i r s t formed woolly f o l l i c l e s have 40 developed a f u l l complement of accessories. The l a t e r formed secondary f o l l i c l e s are forming by now and they a r i s e i n pairs or groups and i n d i v i d u a l l y are of varying sizes and i n developmental stages 2 to 3 a . There i s no trace of the sebaceous gland as yet. In 2 3 1 mm stage the c e l l s c o nstituting the core of l a t e r formed secondaries show "upward streaming" appearance. Melanocytes are also noticed. By 3 3 5 nun stage the hairs have d e f i n i t e l y emerged i n a l l of the f i r s t formed secondaries. Later formed secondaries are s t i l l developing and new ones forming. The f i r s t formed secondaries often possess a bent bulb end — t h e external root sheath being s l i g h t l y thicker i n the angle of the bend. At 3 3 6 mm stage — some of the f i r s t formed secondaries have started reaching r e s t i n g stage, but the l a t e r formed secondaries s t i l l appear to be developing through stages 2 b to 3 a . This trend i s continued i n subsequent samples. In a f i v e week fawn a l l f i r s t formed secondaries are i n r e s t i n g stage but l a t e r formed secondaries are s t i l l forming and developing. I have not estab-l i s h e d the age at which a l l f o l l i c l e s are complete. F o l l i c l e anatomy Montagna ( 1 9 5 6 ) and Montagna and E l l i s ( 1 9 5 8 ) have summar-ized the current concepts about structure of the h a i r f o l l i c l e and i t s function. Studies of S t r a i l e ( 1 9 6 5 ) , P r i e s t l y and Budall ( 1 9 6 5 ) , Cohen ( 1 9 6 5 ) . have also furthered our understanding of some of i t s s t r u c t u r a l aspects. My material did not permit study of c e l l u l a r and i n t r a c e l l u l a r d e t a i l . Auber's ( 1 9 5 0 ) contribution on f o l l i c l e anatomy i s of p a r t i c u l a r importance here as i t deals with an ungulate hair f o l l i c l e (sheep). Anatomically the hair f o l l i c l e can be considered i n the following parts. Secondary f o l l i c l e s FIGURE 14.1 Developing secondary f o l l i c l e s . Longitudinal section. Notice the developing f o l l i c l e and the dermal papilla-; H. & E. FIGURE 14-. 2 Paired secondary f o l l i c l e s developing. Longitudinal section. One member is larger than the other. H. & E. FIGURE 14.3 Branching secondary f o l l i c l e s . Longitudinal section. H. & E. FIGURE 14.4 Fi r s t formed and later formed secondaries. Longitudinal section. Notice the arrector p i l i i muscle in f i r s t formed secondary f o l l i c l e . H. & E. For explanation of abbreviations used please see Appendix IV; Page 214. 42 FIGURE 14.5 Paired secondary f o l l i c l e s i n adult material. Longitudinal section. Notice the compact epidermis the peeling stratum corneum and the non medullated hairs i n f o l l i c l e s . H. & E. FIGURE 14.6 Secondary f o l l i c l e s , a d u l t material, l o n g i t u d i n a l section, of lower part. Notice the well developed external root sheath and i t s membranes. The hair produced i s non medullated. H. & E. For explanation of abbreviations used please see Appendix IV, Page 214. 44 F i g . 15. Details of f o l l i c l e anatomy. 46 ECTAL SIDE STRATUM CORNEUM. . EPIDERMIS DISTAL (UPPER) REGIONS ENTAL SIDE FIBRE DUCT OF SEBACEOUS SWEATGLAND PROXIMAL (LOWER) REGIONS OUTER ROOT-SHEATH ECTAL SIDE OF FOLLICLE FIG. 15.1 LONGITUDINAL-SECTION OF PRIMARY FOLLICLE ENTAL SIDE OF FOLLICLE OUTER ROOT-SHEATH HENLES LAYER-HUXLEY 'S LAYER-i I CUTICLE OF ROOT-SHEATH-, I ! — F I B R E j I CORTEX J ! ! j MEDULLA ! !l ! ! UNDIFFERENTIATED REGION OF BULB FIG. 15.2 DETAILS OF BULB, LONGI-TUDINAL SECTION FIG. 15.3 DETAILS OF MEDULLA" NUCLEAR CAVITY ITOSES REGION OF HOMAXONOUS CELLS AFTER AUBER (1950) 47 The connective tissue sheath This i s common to a l l types of f o l l i c l e s . The dermal elements are associated with the f o l l i c l e s since stage l a . In subsequent developmental stages there i s a d e f i n i t e connective tissue layer enclosing the f o l l i c l e and dermal p a p i l l a . In e a r l i e r stages i t i s continuous with the dermal p a p i l l a — i n l a t e r stages i t i s d i s t i n c t from i t . In mature f o l l i c l e s l't'.s c e l l s are compactly arranged. The glassy membrane This i s a c h a r a c t e r i s t i c feature of a l l f o l l i c l e s but i s v i s i b l e only i n those that are mature but a b t i v e l y growing, then only i n the lower segment. I t i s a hyaline glassy membrane located between the external root sheath and connective tissue sheath. This membrane i s more prominent, almost double the thick-ness i n the secondary f o l l i c l e s , than i n the primary. Curiously a similar membranous structure has also been detected between the external root sheath and the inner root sheath. Such a membrane has not been referred to i n any other f o l l i c l e s and may be a c h a r a c t e r i s t i c cervid feature. I t i s not always c l e a r l y v i s i b l e none the less i s a facet worthy of further i n v e s t i g a t i o n . External root sheath In the early f o e t a l stages t h i s Is distinguished by i t s larger c e l l s and nuclei and by the fac t that i t forms the bound-ary of the f o l l i c l e . In the 287 mm stage onward the external root sheath at t a i n s i t s c h a r a c t e r i s t i c form and the c e l l s have a clear cytoplasm and prominent n u c l e i . 4 8 Anatomically the external root sheath can be divided into three regions. a) As a covering of the f o l l i c l e bulb i t i s one c e l l e d i n thickness and i t i s made up of compact well nucleated c e l l s . b) In the part of f o l l i c l e above the bulb i t has a s t r a t i f i e d structure, here i t becomes two to three layered. The c e l l s adjoining the inner root sheath are i r r e g u l a r i n outline with oval n u c l e i . Those towards the periphery are oriented i n a d i r e c t i o n perpendicular to the axis of the f o l l i c l e and bear elongated n u c l e i . c) Towards the apex of the f o l l i c l e the external root sheath becomes reduced i n thickness and merges with the epidermis. This i s noticed i n a l l the f o l l i c l e types. The external root sheath of the large guard hair f o l l i c l e i s thicker and has larger c e l l s when compared to the other f o l l i c l e s . In the case of l a t e r formed secondaries the external root sheath appears at times thicker on one side than on the other, but t h i s i s not uniform at a l l . The inner root sheath Starting from the periphery the inner root sheath consists of the following l a y e r s : a) Henle 1s layer b) Huxley's layer c) Inner root sheath c u t i c l e In Odocolleus the inner root sheath does not show any r a d i c a l departure from the general mammalian features. The inner root sheath components are not c l e a r l y observable i n the pre-n a t a l l y developing f o l l i c l e s . They are best studied i n the upper half of the bulb of the adult f o l l i c l e when a c t i v e l y producing ha i r , and my observations on them are as follows: Deer primary f o l l i c l e bulb FIGURE 16.1 Close up of f o l l i c l e bulb. Longitudinal section. Notice the dermal p a p i l l a and i t s s t a l k , so also other f o l l i c l e components. H. & E. FIGURE 16.2 C e l l layers i n the inner root sheath. Longitudinal section. Notice c e l l s of Henle's layer, Huxley's layer, inner root sheath c u t i c l e and hair c u t i c l e . H. & E. Medulla formation FIGURE 17.1 Medulla i n primary hair f o l l i c l e . Notice the i n t r a c e l l u l a r c a v i t i e s . H. & E. FIGURE 17.2 Medulla i n white tipped h a i r of fawn b i r t h coat. Notice the absence of i n t r a - c e l l u l a r c a v i t i e s . H. & E. For explanation of abbreviations used please see Appendix IV. Page 214. 50 Fib F SWD 51 Henle 1s layer Most prominent of inner root sheath l a y e r s . C e l l s are large and rounded. It i s bounded on the outer side by a glassy membrane, v i s i b l e at places and then beyond that by the external root sheath. It i s one c e l l e d i n structure and i s more darkly staining with eosin - haematoxylin than other inner root layers. The layer also has fibrous material whose percentage increases as one proceeds towards the f o l l i c l e o r i f i c e . Huxley's layer This also i s one c e l l e d i n thickness, but the c e l l s are oval, a l i t t l e smaller than Henle's layer c e l l s , and compared to i t are l i g h t l y s t a i ning. Inner root sheath c u t i c l e These c e l l s are rounded i n outline and the smallest of inner root sheath c e l l s . As they r i s e upwards they elongate i n the d i r e c t i o n of the f o l l i c l e axis, and form downward pointing scales which in t e r l o c k with those of the hair c u t i c l e . Thus the hair and the inner root sheath move upwards together i n the f o l l i -c l e t i l l they reach the v i c i n i t y of the sebaceous gland, where the inner root sheath breaks up. The Henle's and Huxley's layer fuse together i n the upper reaches of the f o l l i c l e , t i l l they also break up i n the v i c i n i t y of the sebaceous gland. S t r a i l e (19&5) suggests that the root sheath and the dermal p a p i l l a together a f f e c t the shape, size and movement of hair and therefore appear to be of great consequence. 52 The f i b r e anatomy The f i b r e can be divided into i t s three components, c u t i c l e , cortex and medulla. The hair c u t i c l e In the upper regions of the bulb, the hair c u t i c l e c e l l s , which are rounded and larger than the adjoining c e l l s of inner root sheath, c u t i c l e , are easy to d i s t i n g u i s h . As they r i s e upwards they elongate i n the axis of the f o l l i c l e and form the c u t i c u l a r scales of the h a i r . These are pointing upwards and interlock with those of the inner root sheath. The cortex Auber (1950) categorizes the d i f f e r e n t i a t i o n of cortex within a f i b r e into four stages. a) The "preelongation region" b) The region of " c e l l u l a r elongation" c) The c o r t i c a l "prekeratlnization region" d) The f u l l y "keratinized region" In Odocolleus the formation of the cortex has not been observed w e l l . In hair f i b r e s with prominent medulla, the cortex i s reduced to a t h i n s t r i p between the hair c u t i c l e and the medulla. Most of the guard hairs are of t h i s type. But i n smaller f i b r e s , e.g. l a t e r formed secondaries, the medulla i s absent and the cortex with i t s sheath of c u t i c l e constitutes the f i b r e . In the other h a l f of the bulb the c o r t i c a l c e l l s are char-acterized by t h e i r rounded appearance and large number of 53 melanocytes. In the higher regions of the "bulb the c o r t i c a l c e l l s get elongated i n the axis of the f o l l i c l e and when f u l l y keratinized from a compact homogeneous mass. No evidence of c o r t i c a l f u s i has been detected i n Odocolleus. In the guard hairs the cortex of white tipped hairs i s better developed and i s two to three times thicker than that of other guard h a i r s . The medulla In Odocolleus many of the guard hairs are heavily medullated. The medullary c e l l s are noticed r i s i n g on each side of the dermal p a p i l l a i n the upper half of the bulb. Externally on either side they are bounded by c o r t i c a l c e l l s . They are formed on the lower part of the bulb and have larger nuclei than the c o r t i c a l c e l l s . I n i t i a l l y t h e i r c e l l margins are not d i s t i n c t but when observable are triangular or rhomboidal i n form. The nuclei are large and melanin granules have been noticed i n the c e l l s . As the c e l l s r i s e to the upper l i m i t s of the dermal p a p i l l a they are f u l l of granular and fibrous material. As they extend further, vacuoles form i n the c e l l s and Increase i n size, subsequently occupying the whole c e l l and relegating the nuclei to the c e l l wall nearest to the dermal p a p i l l a . The medullary c e l l margins are strong and quite prominent and together with the cen t r a l c a v i t i e s present the c h a r a c t e r i s t i c medullar features. Auber ( 1950) has elegantly discussed the formation of medulla and though Odocolleus follows the same general pattern many of the d e t a i l s as discussed by Auber have not been observed. The f o l l i c l e bulb and dermal p a p i l l a The base of the f o l l i c l e which encloses the dermal p a p i l l a 54 i s c a l l e d the f o l l i c l e bulb. The f o l l i c l e base f i r s t becomes bulbous i n 181 mm foetus. The dermal elements l a t e r to constitute the dermal p a p i l l a are located adjoining the f o l l i c l e base. In a 235 nmi foetus the f o l l i c l e base gets notched and the dermal p a p i l l a elements present a rounded more compact form. At 269 mm stage as much as three fourth's of the dermal p a p i l l a i s enclosed by the f o l l i c l e base. In a 448 mm foetus the r e l a t i o n s h i p between dermal p a p i l l a f o l l i -c l e bulb, and the covering connective tissue sheath becomes apparent. The dermal p a p i l l a i s more or les s f u l l y enclosed by the f o l l i c l e base and maintains contact with the connective tissue by means of a d i s t i n c t s t a l k . This i s c h a r a c t e r i s t i c of the adult material too. The wall of the bulb i s epidermal i n o r i g i n and an extension of the external root sheath. I t i s responsible for giving r i s e to the c e l l s which constitute the various f o l l i c l e s and f i b r e l a yers. These c e l l s as they a r i s e i n the lower half of the bulb are undifferentiated but as they r i s e to upper regions of the bulb they get organized into the rudiments of d i f f e r e n t f o l l i c u l a r and f i b r e l a y e r s . The dermal p a p i l l a , as the name suggests, i s dermal i n o r i g i n and i s believed to supply nutrients to the developing f o l l i * c l e . I t consists of an agglomeration of well nucleated c e l l s . I t ' s exact r o l e i n the biology of the f o l l i c l e s i s complicated and not well understood but has been discussed by Cohen (1965). In Odocolleus i t has been noticed that heavily medullated hair f o l l i c l e s have rounded bulbs and spatulate dermal pap i l l a e , whereas i n non medullated hair f o l l i c l e s i t Is oval and the dermal 55 p a p i l l a has a narrow appearance and pointed apex. In the white tipped hair f o l l i c l e s , characterized by greater cortex a smaller non vacuolated medulla, the dermal p a p i l l a has a pointed apex. Thus p a p i l l a shape has d i r e c t r e l a t i o n s h i p with the type of hair produced. What exactly t h i s r e l a t i o n s h i p i s and how i t operates i s beyond the scope of the present work. Melanocytes The growing hair f o l l i c l e s of Odocoileus are charaterized by the presence of melanocytes. In guard hair f o l l i c l e s they f i r s t appear i n 202 mm foetus. The v i s i b l e melanocytes are dark coloured, few, and scattered within the f o l l i c l e . Some may be located i n i t s external margin and an i s o l a t e d few may occur even i n basal layer of the epidermis. Subsequently they concentrate i n the bulb. The melanocytes here are d e n d r i t i c . Of course the amount of melanocytes depends on the colour-a t i o n and type of f i b r e s being produced. The melanin deposited by melanocytes i s confined to the hair f i b r e only and there too to the cortex, and the basal parts of the medulla. Variations i n colour of summer and winter hairs i n adult can be explained on the basis of the biochemical a c t i v i t y of melanocytes. Sweat gland A l l f o l l i c l e s , except those of the woolly underhalr, possess apocrine sweat glands. I n i t i a l l y they develop as bag l i k e out-growths from the neck of the f o l l i c l e . The sweat gland at t h i s stage i s a s o l i d outgrowth devoid of any lumen and the c e l l s consitutuing i t are si m i l a r to those of the f o l l i c l e . Sweat gland FIGURE 18.1 Sweat gland forming at 202 mm stage. Longitudinal section. H. & E. FIGURE 18.2 Sweat gland at 236 mm stage. Longitudinal section. Notice the pos i t i o n of sweat gland and arrector p i l l i muscle. The hair i s developing. H. & E i FIGURE 18;3 Sweat gland at 269 mm stage; Longitudinal section. Notice i t s desposition i n r e l a t i o n to sebaceous gland, and the gentle waviness which has begun. H. & E. FIGURE 18.4 Sweat gland i n adult material. Longitudinal section. Note the c o i l s have been sectioned and possess a one c e l l thick l i n i n g . The inner root sheath and hair c u t i c l e are also c l e a r . H. & E. For explanation of abbreviations used please see Appendix IV. Page 214. FIG 18.4 58 By the 211 mm stage the sweat gland has reached up to the top of f o l l i c l e bulb, and d i f f e r e n t i a t i o n begins to take place within the gland. The d i s t a l part develops a lumen, but the proximal part of the gland, where the sweat duct forms i s at t h i s stage s t i l l a s o l i d mass of c e l l s . The complete gland does not d i f f e r r a d i c a l l y from the t y p i c a l mammalian pattern i n form or i n constituent c e l l s . The thickness of lumen wall i s about 3 3 / ^ and the lumen diameter (inner) i s about 184/*- . The wall of the duct i s single c e l l e d and i t s thickness as well as the diameter of the duct i s about 42/*- . The sweat duct passes over the surface of the sebaceous gland i n between i t s two lobes and opens by means of a funnel shaped opening into the hair f o l l i c l e near the skin surface. Sebaceous gland A l l f o l l i c l e s except the smallest of the secondaries possess sebaceous glands. The primaries and f i r s t formed secondary f o l l i c l e s possess bilobed sebaceous glands, t h i s i s not so i n smaller secondaries. The sebaceous glands originate a f t e r the sweat glands, and t h e i r f i r s t traces are observed i n 181 mm foetus. They are developed f i r s t i n larger f o l l i c l e s . The sebaceous gland r u d i -ments consist of few large rounded c e l l s with clear cytoplasm and prominent n u c l e i . By 269 mm stage they resemble i n appearance a grape bunch. By 335 mm the bulk of the gland i s formed of large c e l l s with clear cytoplasm a large c e n t r a l l y placed nucleus. Sebaceous gland FIGURE 19.1 Sebaceous gland rudiment, 2 3 5 mm stage. Longitudinal section. Notice i t s p a r t i c i p a t i o n i n h a i r canal formation. H. & E. FIGURE 19.2 Sebaceous gland at 2 6 9 mm stage. Longitudinal section. Notice the t y p i c a l gland c e l l with prominent n u c l e i . The developing hair i s l y i n g next to i t . H. & E. FIGURE 19.3 Sebaceous gland opening i n adult material. Longitudinal section. Notice the lobed nature of the gland and i t s short duct which opens into the h a i r f o l l i c l e . H. & E. FIGURE 19.4 Sebaceous gland and the f o l l i c u l a r f o l d s . Longitudinal section. The folds are caused by di s i n t e g r a t i o n of inner root sheath near sebaceous gland. H. & E. For explanation of abbreviations used please see Appendix IV. Page 214. 60 63) Arrector p l l l l muscle This i s present i n primary and f i r s t formed secondary f o l l i c l e s . I t i s formed from dermal fibrocytes and approches the f o l l i c l e on an oblique course, from a region just below the epidermis. In a 2 1 1 mm foetus the fibrocytes i n the dermis appear to be a l i g n i n g to form the muscle. At t h i s stage one d i s t a l end of the sweat gland i s forming a lumen. The sweat gland passes between the strands of the developing muscle. As maturation proceeds the number of f i b r e s increases within the muscle. They are elongated, and compactly arranged, and have flattened n u c l e i . Ental swelling The hair f o l l i c l e as well as the hair that i t gives r i s e to are always i n c l i n e d at an angle with respect to the skin surface. The side forming the acute and obtuse angles with the skin are refer r e d to as ental and e c t a l r e s p e c t i v e l y . The ental side of hair f o l l i c l e s have been noticed i n many species to possess a swelling during the course of development — a swelling commonly referred to as the ental swelling. This constitutes the region where the a r r e c t o r l s p i l i i muscle becomes attached to the f o l l i c l e . In Odocolleus, i n a 2 1 1 mm foetus the ental swelling i s just noticeable. I t i s more prominent by 2 3 5 mm stage, but from 2 8 7 mm stage onwards i t diminishes. In a c t i v e l y growing f o l l i -c l e s producing them i t i s not noticeable. I did not f i n d any ental swelling i n the secondary f o l l i c l e s . Lyne and Heideman ( 1 9 5 9 ) have reviewed theories regarding o r i g i n of the ental swelling and have concluded that i t i s not 62 formed by t r a c t i o n of arrector p i l i i muscle, as i t i s present even when there i s l i t t l e or no muscle. This has also been cor^o-:^orjated by my observation on the Odocolleus material. The hair canal Lyne (1957) has discussed at some length the process of hair canal formation i n the merino foetus. Observations on Odocolleus indicate that a process akin to that i n merino takes place here. A 211 mm foetus shows within stratum spinosum granular material deposited obliquely with respect to the skin surface. This i s just above the f o l l i c l e and appears to represent the granulation stage r e f e r r e d by Lyne. Simultaneously sebaceous c e l l s present i n the neck of the f o l l i c l e are i n process of d i s i n t e g r a t i o n . In a 269 mm foetus the hair canal i s d i s t i n c t and leads obliquely from hair f o l l i c l e towards skin surface. The hair canal formation starts by stages 3a» 3t», and i s completed by stage 7« The sebaceous gland c e l l s as well as those of the stratum spinosum take part i n i t . Paired f o l l i c l e s Lyne and Heideman (1959) f i r s t described a case where two f o l l i c l e s develop separately but i n close proximity of each other and open to the exterior by means of a common opening. Only secondary f o l l i c l e s of Odooolleus sometimes exhibits t h i s . The common hair canal has not been established for these f o l l i c l e s — but i s l i k e l y since they have common opening and ar i s e separately. Usually i n paired f o l l i c l e s , one i s smaller than i t s compatriot. 6 3 Branched f o l l i c l e s The l a t t e r formed secondaries i n Odocolleus occur i n groups of three or four, of which one f o l l i c l e i s large and the others sucessively smaller. The large f o l l i c l e may possess a r e l a t i v e l y large sebaceous gland and other assorted f o l l i c l e s appear : V , i n development to be derived from t h i s large f o l l i c l e and may lack sebaceous gland. F o l l i c l e density The density of hair f o l l i c l e s varies with advancing f o e t a l p stages. The f o l l i c l e number per mm i s affected i n two ways, either by formation of new f o l l i c l e s or by dispersal of f o l l i c l e s by stretching of skin, due to i t s growth. The figures given here should only be taken as i n d i c a t i v e of the trend, since corrections have not been made f o r tissue shrinkage during processing. In t h i s tissue size comparisons are believed to be v a l i d as a l l foetuses were f i x e d and preserved i n the same manner. At the 202 mm stage only primary f o l l i c l e s are forming but due to increase i n f o e t a l size r e s u l t i n g i n stretching of skin, though the t o t a l number of f o l l i c l e s per mm2 i s increasing the number of primaries per mm2 i s decreasing. F o l l i c l e density at th i s stage i s 90 per mm2 (58 primary and 3 2 secondary). By 287 mm stage f o l l i c l e density i s maximum i . e . 108/mm2. (48 primary and 6 0 secondary). Hereafter the f o l l i c l e density continues to decrease and at b i r t h i t i s about 31/nun2 i . e . 1 1 primaries and 20 secondaries. 64 ".Integumentary layers These can "be considered i n the form of the two major components, the epidermis and the dermis. Chase et a l (1953)» have made observations on t h i s subject i n mice and Lyne (1957) has described the development of epidermis i n merino. These are i n t e r e s t i n g contributions shedding l i g h t on aspects of skin frequently ignored. In respect of Odocolleus I have following observations to make: The epidermis In an 89 mm stage the epidermis consists of small c e l l s with prominent rounded n u c l e i . This corresponds to the basal layer of subsequent epidermal stages. With increasing growth of the foetus the epidermis can be distinguished into the following layers: a stratum germinativum or basal layer and a stratum spinosum. The l a t t e r a r i s e s by p r o l i f e r a t i v e a c t i v i t y of the basal layer over which i t l i e s . In a 212 mm foetus i t i s of two layers. The c e l l s are larger than those of the basal layer, have clear cytoplasm and prominent n u c l e i . The c e l l s are i r r e g u l a r to oval and l o o s l y arranged, those nearer the surface appear f l a t t e n e d . Periderm It constitutes surface of the skin and i s formed by stratum spinosum c e l l s flattened and hyalinlzed. It i s a continous layer of uniform consistency with c e l l u l a r components that cannot be distinguished. FIGURE 20 Arrector p i l i i muscle i n adult material. Longitudinal section. H. & E. FIGURE 21 Melanin i n growing hair f o l l i c l e s . Notice i t s heavy deposition i n c o r t i c a l and medulla layer of f o l l i c l e and h a i r . H. & E. Dermis FIGURE 22;0. Dermis i n early developmental stage. Longitudinal section. H. & E. FIGURE 22.2-Dermis i n adult stage. Longitudinal section. Notice the heavy fibrous deposition near f o l l i c l e base. H. & E. For explanation of abbreviations used please see Appendix IVY Page 214. 66 67 In keeping with the advancing stages of f o e t a l and f o l l i c l e development, changes also take place within the epidermis. In early stages of f o l l i c l e development epidermis increases i n thickness; "but as hair development and muturation proceeds the thickness i s reduced. At i t s maximum the epidermis i s 50/*- thick. The increase being most manifest i n the stratum spinosum, which becomes three c e l l s t h ick. In 235 nun foetus with stages of f o l l i c l e development from 2b to 4 , the epidermal c e l l s show tendency towards compactness. At the same time the periderm i s peeling o f f and being replaced by another layer of uniform consis-tency containing many granular deposits. This granular layer may be c a l l e d the stratum granulosum. In a 269 mm foetus some hairs have emerged, and the epider-mis i s greatly reduced i n size being 25/*" t h i c k . The stratum corneum shows laminated structure and the; stratum spinosum i s two layered with flattened c e l l s . In a 4 4 8 mm stage i . e . when fawn i s about to be born, the stratum spinosum has l o s t i t s e n t i t y as a separate layer. Scattered c e l l s may however be noticed between the stratum germinativum and the prominent stratum corneum. In a mature adult the epidermis i s 2$thick. The dermis The preservation of my material was inadequate to permit detailed study of the various elements. Epidermis FIGURE 23.1 Developing epidermis. Longitudinal section. 46.2 mm stage. Notice the stratum germinatlvum and the l o o s l y arranged dermal elements. H. & E. FIGURE 23.2 Developing epidermis at 112 mm stage. Longitudinal section; Note the d i s t i n c t i v e stratum germinativum, f o l l i c l e anlagen i n i t , two layered stratum spinosum and the periderm. Hi & E i FIGURE 23.3 Developing epidermis. Longitudinal section. Notice the enlarged nature of stratum spinosum. H. & E. FIGURE 23.4 Epidermis i n adult material. Longitudinal section. Notice the peeling stratum corneum and compact nature of epidermis and fibrous dermis. H. & E. For explanation of abbreviations used please see Appendix IV. Page 214. 69 70 Summary The hair f o l l i c l e s of Odocolleus can be divided into primary and secondary types. The primaries are f i r s t to originate, and develop i n t r i o s consisting of a larger central primary f o l l i c l e and two smaller l a t e r a l primary f o l l i c l e s . This grouping i s obvious during early developmental stages. A l l primaries possess sweat gland, sebaceous gland and p i l i i muscle. The development of the f o l l i c l e s begins by 1 1 2 mm and by 4 4 8 mm stage they are a c t i v e l y producing h a i r . The secondaries are smaller i n size, a r i s e l a t e r and are divided into f i r s t formed and l a t e r formed. The f i r s t formed secondaries are larger and possess a sweat gland, a sebaceous gland and arrector p i l i i muscle. They s t a r t developing by 2 6 9 mm stage and by 4 4 8 are a c t i v e l y producing hair, some f o l l i c l e s do even reach r e s t i n g stages. The l a t e r formed secondaries are smaller than the f i r s t formed, possess only sebaceous glands, and the smallest among them may even lack these; they may be single, paired or branched. When branched they are i n clu s t e r s of 3 to 4 and are of gradually decreasing s i z e s . The l a t e r formed secon-daries continue to form even postnatally and do not become f u l l y f u n ctional u n t i l i n the fawn winter coat. Some of the central primaries grow and develop at a faster rate, dwarfing f o l l i c l e s adjacent to them. This i s p a r t i c u l a r l y noticeable at 2 8 ? mm stage, subsequently the size discrepancy gets reduced and i s hardly noticeable postnatally. The neck of these f o l l i c l e s has been observed to assume occasionally a 71 bulbous form, but no d e f i n i t i v e sinus has been detected. These f o l l i c l e s have most of the c h a r a c t e r i s t i c s and also the function of the t y l o t r i c h f o l l i c l e s present i n mammals. The types of hair produced by the f o l l i c l e s are varied. The large guard hair f o l l i c l e s produce large guard hairs ( t y l o t r i c h s ?) which are longer and t a c t i l e i n function. The r e s t of the primary f o l l i c l e s produce the intermediate guard hair s , c o n s t i t u t i n g the animal's overcoat. Some of the primaries i n fawn b i r t h coat produce white tipped hairs, responsible for the white spots i n the b i r t h coat. A l l primaries and f i r s t formed secondaries produce medullated hairs, while the l a t e r formed secondaries produce non medullated h a i r s . Anatomically the f o l l i c l e s have basic mammalian features. The following amongst them are however c h a r a c t e r i s t i c and note-worthy. a) A glassy membrane between connective tissue sheath and the external root sheath i s prominent at places, even on the f o l l i c l e bulb. b) An a d d i t i o n a l glassy membrane i s also noticed at places between external root sheath and the i n t e r n a l root sheath. c) The external root sheath i s of uniform thickness around the f o l l i c l e . d) Henle's layer i s single c e l l e d and large, staining more deeply with Haematoxylin and Eosin than does Huxley's layer, which i s also single c e l l e d but smaller. The shape of the dermal p a p i l l a varies with the hair type being produced. In f o l l i c l e s producing heavily medullated hairs i t i s spatulated, while i n those producing non medullated hairs i t has a pointed apex; i t i s also pointed i n the primary f o l l i c l e s , producing white tipped h a i r s . In the early f o l l i c l e development the observable melanocytes 72 are few and scattered. Some may occur even i n the basal layer of the epidermis. By the time hair production commences, they assume d e n t r i t l c form and are heavily concentrated i n the f o l l i c l e bulb. In general the pigmentation i s confined to the hair c u t i c l e , and to the c o r t i c a l region. Some deposition may be noticed even i n the basal region of the medulla. The ental swelling i n Odocolleus f o l l i c l e s was r e s t r i c t e d to primaries and did not have any cause and ef f e c t r e l a t i o n s h i p with the arrector p i l i i muscle. In the hairs produced i n primary and f i r s t formed secondary f o l l i c l e s the medulla i s better developed than the cortex. The hairs from l a t e r formed secondaries i n contrast are non medullated and consist of cortex and hair c u t i c l e . The bulk of the long t i p of a large guard hair i s made of cortex — as c o r t i c a l tissue begins to form e a r l i e r than the medulla. The white tipped h a i r s , have i n the region of the white t i p s greater proportional develop-ment of cortex than other medullated h a i r s . The medulla i n Odocoileus i s very well developed and i s characterized by presence of i n t r a c e l l u l a r c a v i t i e s . The white tipped hairs have however a medulla lacking i n c a v i t i e s ; and the medullary c e l l s are instead f i l l e d with porous and granular material, reminiscent of stages p r i o r to cavity formation i n normal medulla. The sweat gland i s prominent and i t s secretory part i s sinuous. The sebaceous glands are well formed, generally bilobed i n primary and f i r s t formed secondaries, and do not possess d i s t i n c t a c l n l i . They have a short excretion duct and during development pa r t i c i p a t e i n hair canal formation. 7 3 The epidermis undergoes profound change of size during f o l l i c l e development. The layer most affected i s stratum spinosum, which i s three layered at one stage and i n adult animal almost disappears as an e n t i t y . Evidence of periderm being sloughed o f f during embryonic development i s also present. The stratum corneum of adult material has also peeled appearance. The dermis during development gets more and more compact and well organized. The collagen f i b r e s i n the r e t i c u l a r layer reach massive proportions i n the adult. 74 Chapter IV PELAGE MORPHOLOGY AND MOULT PATTERNS INTRODUCTION The present chapter deals with black t a l l pelage, that i s the hairs produced by the f o l l i c l e s , t h e i r morphology and moult patterns. I t appears c e r t a i n that morphological features of hair c o n s t i t u t i n g the pelage contribute to i t s functional e f f i c i e n c y . The timing of the moult also normally bears an important r e l a t i o n -ship to p r e v a i l i n g environmental conditions and i s oriented to-wards the animal's well-being. During i t s l i f e cycle a black t a i l e d deer can be said to possess four d i f f e r e n t pelage types. These are: a) Pawn b i r t h coat b) Pawn winter coat c) Adult summer coat d) Adult winter coat I have studied the d i s t i n c t i v e features of these d i f f e r e n t pelages and the pattern and timing of the moult. MATERIAL AND METHODS The study involved use of l i v e deer as well as tanned hides. The hides were used f o r a general description of the summer and winter phases of the adult coat as well as the fawn b i r t h coat. The winter coat of the fawn, as well as the moult pattern i n animals has been discussed on the basis of observations on l i v i n g animals. Hair samples for measurement and description were co l l e c t e d from s p e c i f i e d regions on the body of the l i v i n g animal. 75 The methods for the study of hair morphology were mostly those of Spence (19&3) a n d - gave good r e s u l t s . Hair samples were co l l e c t e d from s p e c i f i e d regions, care being taken to see that they were not mutilated. Hair length was measured to the nearest millimeter on a p l a s t i c measuring scale. The woolly under hairs were ignored for t h i s purpose. The hair diameters were measured under a compound microscope with c a l i b r a t e d ocular micrometer. To observe gross features of the medulla and the cortex of guard hairs the hairs were cleaned by immersion i n carbon t e t r a -chloride, transferred to xylene for 24- hrs and then placed d i r e c t l y into technicon mounting medium. The deer guard h a i r s had a large medulla which was c l e a r l y observable even without t h i s treatment. A technique suggested by Manby (1932) was used i n the study of scale patterns. Negative impressions of the in d i v i d u a l hairs were made i n a ge l a t i n - g l y c e r i n mixture. The l i q u i f i e d medium i s spread on a glass s l i d e and allowed to s o l i d i f y . After i t s o l i d i f i e s the hair whose scale cast i s to be prepared i s placed on i t . A glass s l i d e i s put on top of i t and the two s l i d e s together, with the hair i n between are warmed on a warming table. When the g e l a t i -nized mounting medium becomes soft pressure i s uniformly applied to the upper side and subsequently both the sli d e s are allowed to co o l . When cold the upper s l i d e i s removed. The hair which i s now fixe d i n the mounting medium i s removed by means of a forcep, leaving the scale Impression behind. 76 Satisfactory hair scale Impressions were also obtained with a method suggested by Dr. J . Bendell of the Dept. of Zoology. This consisted of spreading a t h i n layer of quick-drying airplane glue (Lapage's airplane model cement) and pressing the hair on i t . The mounting medium dries quickly, a f t e r which the hair i s removed, leaving the scale impression behind. The moult patterns were studied on the l i v i n g animal. The moult progress was recorded on cyclostyled sheets having a cervid outline marked on i t . Observations Hair c h a r a c t e r i s t i c s The c h a r a c t e r i s t i c s as manifested by pelage are a suim t o t a l of the c h a r a c t e r i s t i c s of i n d i v i d u a l hair types. I t i s therefore pertinent to discuss the major hair types present and t h e i r char-a c t e r i s t i c s before discussing the d i f f e r e n t coats and hair patterns of moult. Hair types Large guard hairs These are long hairs up to 8 0 mm i n length and uniformally scattered over the body — about 2 cms apart. They possess black t i p s 15 to 2 0 mm long and have a s l i g h t l y crimped shape. They are heavily medullated and morphologically are akin to kemp of sheep and goats. FIGURE 24 Skin surface view at 269 mm stage. Notice emerging large guard h a i r s . FIGURE 25 Skin surface view at 287 mm stage. Notice intermediate guard hairs are also emerging along with large guard h a i r s . FIGURE 26 Fawn b i r t h coat hair array. Notice the hair types. FIGURE 27 Fawn winter coat guard hair array. Notice the hair types. For explanation of abbreviations used please see Appendix IV,1 Page 2 l 4 v 78 79 Intermediate guard hairs These hairs are abundantly present In the pelage and compose the bulk of I t . They give the pelage Its c h a r a c t e r i s t i c colour-at i o n . They vary from 18 to 44 mm i n length and bear a black t i p 3 to 5 ™ i n extent. Their form Is kemp l i k e — p a r t i c u l a r l y the longer h a i r s . Hairs of varying lengths and thickness occur but a l l are larger than the hairs produced i n secondary f o l l i c l e s . The smaller among them however may conceivably a r i s e i n f i r s t formed secondaries. These hair types are not •crimpy 1 kemp types — and can be c a l l e d " T r a n s i t i o n a l " hair types. In fawn b i r t h coat t h i s type constitutes the bulk of the undercoat. Woolly under hairs These are woolly hairs which constitute the under coat of the animal. They are t h i n and curly — diameter varying from 18/"-to 16/*- . They are non medullated. Beard type These are long hairs which d i f f e r from kemps i n not being crimpy. They are soft and of variable length. In Odocolleus these hairs are r e s t r i c t e d c h i e f l y to black patch on the t a i l , a x i l l a e , inguinal region, posterior margin of rump. White tipped hairs In addition to these hair types the fawn b i r t h coat pos-sesses white tipped h a i r s . These are of the same length and type as intermediate guard hai r s , but possess white d i s t a l extremities 5 to 8 mm i n length. These hairs are responsible Adult summer coat FIGURE 28.1 Adult summer coat hair array. Notice the hair types. FIGURE 28.2 Close up of summer coat. Adult winter coat FIGURE 29.1 Adult winter coat hair array. Notice the hair types. FIGURE 29.2 Close up of winter coat. Notice i t s thick nature. For explanation of abbreviations used please see Appendix IV, Page 214, 81 82 for white spots on fawn b i r t h coat. The extreme t i p of a l l types of hairs i s pointed and devoid of any pigment. Cortex, medulla and s c u t e l l a t i o n Observations were also made on the c u t i c u l a r scale patterns medulla and cortex features of these hair types. In fawn b i r t h coat a l l guard hairs presented scale pattern of i r r e g u l a r waved mosaic nature with margins smooth and i n t e r -mediate. (Terminology as per Spence (1963) , Wildman (1937) )• The medulla was wide and of unbroken l a t t i c e type. Cortex was reduced on the shaft and could only be d i s t i n c t l y seen as a translucent homogeneous mass at the t i p and base of the h a i r . The white tipped hairs had a greater development of cortex and the medulla, though wide, lacks i n t r a c e l l u l a r c a v i t i e s , The undercoat hairs are mostly medullated and possess fragmental medulla. The scale pattern present i s a v a r i a t i o n of the coronal scales — involving two scales that envelop the hair shaft and not one as i n the case of true coronal scale pattern. In fawn winter coat the scales on guard hairs are of i r r e g -u l a r mosaic and not i r r e g u l a r waved mosaic. The features of cortex and medulla are the same as before. In adult summer coat the features of cortex and medulla are same. The guard scale patterns are the same except that at d i s t a l extremities the margin changes from "intermediate" to close. Woolly under hairs are missing i n t h i s coat. In the adult winter coat there i s greater d i v e r s i t y . The features of cortex and medulla are same but s c u t e l l a t i o n v a r i e s . 83 FIG. 30 ANTERO POSTERIOR DISTANCE BETWEEN SCALE MARGINS AFTER SPENCE (1963) FIG. 31 ARRANGEMENT OF HAIR SCALES AFTER SPENCE (1963) 84 Large guard hairs b a s i c a l l y have i r r e g u l a r mosaic scales, margin smooth, intermediate to distant — i n r e s t of the hair margin i s smooth — intermediate to near. The Intermediate guard hair scales are regular mosaic, margin smooth and distant but i n d i s t a l end margin becomes smooth, intermediate to near. The beard type have i r r e g u l a r waved mosaic scales with margins smooth and intermediate, i n the mid part of the hair shaft as well as d i s t a l part margin may be intermediate to close. The woolly hairs have scales as before and are non medullated. In fawn b i r t h coat the hairs are softer and of smaller diameter. The number of non medullated f i b r e s i s very low. The smaller hair types bear a fragmental type of medulla as opposed to the wide l a t t i c e d type present i n guard h a i r s . Most of the fawn undercoat i s made up of t r a n s i t i o n a l hair types which are a l l medullated. In fawn winter coat the hairs have attained larger diameter and length. The true non medullated woolly hairs are present i n large numbers and consist only of cortex and c u t i c l e . In adult summer coat i n contrast to adult winter coat the hairs are of smaller diameter and greater length. The woolly undercoat i s missing. In adult winter coat the hairs are shorter but of greater diameter, than those i n adult summer coat. The medulla i s wide and of larger diameter, The scale pattern i s greatly v a r i a b l e . A well developed woolly undercoat i s present. Generally i n medullated hairs i t can be said that areas with larger diameter have a regular mosaic scale pattern with margins smooth and distant, whereas i n hairs with smaller diameter the 85 scales become i r r e g u l a r mosaic to ir r e g u l a r waved mosaic with smooth margins and distance between margins varying from i n t e r -mediate to near. In woolly under hairs there i s no change of diameter i n the main hair shaft consequently scale pattern remains uniform. Hausman (1930), Mahal et a l (1951) have made some observa-tions on scale pattern i n animals. The general conclusion being that there i s no r e l a t i o n s h i p of any of the att r i b u t e s i . e . number of scales per unit length, average v i s i b l e scale height e t c to breed or wool type. Colouration The other important aspect of hair i s i t s colouration. That of the d i s t a l h a l f of the t o t a l hair length i s important i n determining the pelage colouration. The extreme t i p of most hairs i s generally colourless. This i s followed by a black coloured zone, which r e a l l y c o n s t i -tutes the v i s i b l e part of the hair t i p . This region i s followed by zones of whitish yellow, reddish yellow or grey depending on the nature of hair coat. The colour v a r i a t i o n i n d i f f e r e n t coats or over d i f f e r e n t body regions of the same coat as they ex i s t are caused by presence or absence of these coloured zones, or changes i n t h e i r extent i n the d i s t a l end of the h a i r . These are discussed i n a subsequent chapter i n d e t a i l . The b i r t h coat of fawns and the summer coat of adults show resemblances to each other. The v i s i b l e part of hairs i n the pelage consist of a black t i p , followed by a reddish yellow hair shaft. The basal part of each hair i s l i g h t coloured ending i n a plgmentless area of the bulb. The large guard hairs have 86 proportionately longer black t i p s . The beard type hairs are of uniform colouration either black or white. In the winter coat of fawns and adults the black tiped zone i s followed by a yellowish white zone. This i n turn i s followed by greyish colouration fading towards the base. In the large guard hairs the 'yellowish 1 zone i s replaced by a 'reddish yellow' zone of greater length. Thus the colouration here i s more remi-*-niscent of the summer coat and indicates that even i n winter coat the melanocyte a c t i v i t y i n large guard hair f o l l i c l e s i s d i f f e r e n t from the adjoining hair f o l l i c l e s . The fawn winter coat hairs may be completely black coloured over the entire length. As before the beard type hairs are either completely black or white. The woolly under hairs which occur i n bulk i n the winter coat are not v i s i b l e externally. When a c t i v e l y growing they are greyish but when r e s t i n g are v i r t u a l l y colourless. In the course of t h i s study observations were made on hair length, diameter and the extent of the d i f f e r e n t colour zones, i n the large and intermediate guard hai r s , i n d i f f e r e n t body regions of the animal and i n d i f f e r e n t coats. This i s i n an attempt to put i n quantitative terms, what the i r i n t e r r e l a t i o n s are and how they a f f e c t the pelage colouration i n d i f f e r e n t body regions and i n d i f f e r e n t coats. The colouration of the pelage as a whole does not remain s t a t i c during the course of the year. The winter coat i n i t s early phases presents a steely grey appearance but with continued hair growth and environmental e f f e c t t h i s fades to a yellowish grey colouration, which i s retained most of the time. Just p r i o r to shedding the coat has a well worn look and a faded appearance. 87 The summer coat of adults Is reddish brown when i n prime but fades to paler shades before moult. The upcoming greyish woolly undercoat i n the l a t e r parts of the summer also contributes,to changing i n colour to a greyish shade. Hayman and Nay (i960) have c l a s s i f i e d stages i n a c a t t l e coat during the course of the year, on the basis of "appearance of the coat, the number of loose f i b r e s , t h e i r degree of looseness, and the progress of shedding". Each stage i s given a score, there being twelve stages and the score of the l a s t one being twelve. These stages cannot be applied " i n toto" to deer. Whereas i n c a t t l e a percentage of hairs i s being shed a l l the time, t h i s i s not so i n deer. In contrast to the cattle, passage of a hand over the deer body when hairs are i n r e s t i n g stages hardly brings about any loss of hairs even though the hairs can be plucked e a s i l y . Coat description and pattern of moult We have already referr e d e a r l i e r to the f a c t that the black t a i l deer i n course of i t s l i f e cycle has four types of coats. The c h a r a c t e r i s t i c s of hair types constituting these coats have also been referre d to. Now I s h a l l endeavour to describe the features of these coats as they occur on the animals and the moult processes by which one coat type gives way to another. Fawn b i r t h coat The black t a i l fawns are born i n summer mostly i n May and June. The coat with which they are born and which i s retained 8 8 distal end FIG 32.1 DIFFERENT BODY REGIONS OF THE BLACK TAIL DEER. SIDE VIEW FIG. 32.2 HEAD, FRONT VIEW .FIG. 32.3 POSTERIOR VIEW 89 t i l l i t s moult i n l a t e summer or autumn i s very soft and gives the young a f l u f f y appearance. The softness of the coat i s rel a t e d to fineness of the hair types constituting the coat, whereas the f l u f f i n e s s may be correlated with the greater f o l l i -cular density and the d i s p a r i t y i n the lengths of large guard ha i r s v i s a v i s others i n the pelage. The coat i s brownish i n colour, darker d o r s a l l y , fading l a t e r a l l y to l i g h t e r shades. There are two p a r a l l e l rows of white spots on the back, the others being scattered along the flanks and thighs. The hairs on the face and the d i s t a l ends of the limbs are shorter than those over the res t of the body. The hairs occurring i n the a x i l l a r , inguinal, rump and t a i l regions are i n the same re l a t i o n s h i p longer. In the a x i l l a and inguinum t h e i r density appears l e s s . T h e . t a i l c h a r a c t e r i s t i c a l l y bears a black t i p . In contrast to the brownish shade present dor s a l l y the hairs occurring i n the neck, chest, and abdomen are l i g h t e r i n colour,. Those occurring i n the a x i l l a , inguinal region, ventral side of the t a l l and posterior margin of the rump are white. Hairs i n the v i c i n i t y of the t a r s a l and metatarsal glands are longer, coarser, and e r e c t i l e . Moult i n the fawn b i r t h coat There was some v a r i a t i o n i n the i n i t i a t i o n and completion of. the moult of the fawn leading to i t s shedding of the b i r t h coat and a q u i s i t i o n of the winter coat. This generally begins i n the l a t e summer and i s completed i n October, by which time the adults also have assumed the winter coat. 90 Moult i n the fawn can "be "best described i n terms of four stages which follow each other i n a time sequence and are easy to d i s t i n g u i s h . These stages have been categorized on the basis of the fawn's appearance as modified by the moult i n progress. Stage I (July) The hairs covering the ear pinnae are shed f i r s t , g iving the ears a naked appearance f o r a while. Simultaneously the hairs surrounding the eyes are shed and replaced by cream-coloured hairs which d i s t i n c t l y demarcate t h i s area. Hairs are then replaced on cheeks, front part of the face and forehead. The l a s t parts of the head to moult are the inner sides of the ears and here the dark coloured margins lose the hairs f i r s t . At the end of t h i s stage the head has completely moulted into the winter pelage. I n i t i a l l y i t has a glossy appearance and i s i n d i s t i n c t contrast to the b i r t h coat s t i l l prevalent on the body. Stage II (August) Moult then proceeds on the under side of the neck and chest, while the hairs on the body are r e l a t i v e l y i n t a c t . This phase i s followed by the general loss of the spotted nature of the coat as the white tipped hairs are l o s t . fhu§ t h i f i hairs shed e a r l i e r than many others i n the pelage. This i s i n t e r e s t i n g because none of the other intermediate guard hairs are being shed at t h i s stage. The mechanism of control over such apparently precise l o c a l moulting i s not known. Towards the end of t h i s phase there i s considerable loss of Moult stages fawn b i r t h to fawn winter coat FIGURE 33.1 Fawn In b i r t h coat. FIGURE 33.2 Moult stage 1. Head has moulted, FIGURE 33 .3 Moult stage I I . The neck i s moulting but b i r t h coat i s inta c t on most of the body. FIGURE 33 .4 Moult stage I I I . The white spots have a l l disappeared but b i r t h coat i s l o o s l y present over the body. FIGURE 34 Fawn i n winter coat. 92 93 hair over the body. It has no pattern but i s general. The hairs most affected are the t r a n s i t i o n a l types forming the bulk of the under coat. At the end of t h i s stage the fawn shows a thinned out appearance with only larger and intermediate guard hairs remaining. Stage I I I (September) The upcoming winter coat i s seen through the thinned out b i r t h coat. The remaining b i r t h coat hairs are now shed d i r e c t -i o n a l l y i n a cauded wave. Stage IV (Oc tober) The fawn i s now i n f u l l winter coat, except that the old b i r t h coat hairs are s t i l l present i n the v i c i n i t y of t a r s a l and metatarsal glands, these are progressively replaced. Fawn winter coat By October end the fawns are i n the i r f u l l winter coat. This grey coat greatly resembles the winter coat of the adult. The hairs have smaller diameter and length, and are softer than those of adult winter coat. A woolly undercoat i s present here. Other d e t a i l s of hair and t h e i r topographical v a r i a t i o n are the same as i n the adult. Moult from fawn winter coat to adult summer coat The yearling animal on moulting from fawn winter coat — assumes a summer coat i d e n t i c a l to that of the adult. The process of moult could not be documented as the experimental animals had 94 b i t t e n o f f t h e i r coat to a great extent and no meaningful observation could be made. Linsdale and Tomich (1953) state that i n mule deer yearlings the spring moult starts l a t e r than i n the adults and extends for a longer period. The moult i s said to have no pattern but i s mani-fested by gradual replacement of old hairs by the new coat growing underneath. This i s i n contrast to adult spring moult i n which a pattern can be discerned. Adult summer coat This coat i s very d i f f e r e n t from the adult winter coat. The standard hair types, t h e i r morphology and colouration have already been r e f e r r e d to. In general the summer coat hairs are longer and straighter than t h e i r winter counterparts. The kemps possess much les s wavy form. The percentage of hairs below 30 mm length i s much less than i n the winter coat. The hair diameter i s also smaller and less variable i n r e l a t i o n to hair length than i n the winter coat. The summer pelage i s yellowish red i n contrast to yellowish grey of the winter coat. The parts of the hair responsible for i t are the v i s i b l e d i s t a l h a l f of the hair consisting of the black t i p and the reddish yellow hair shaft. The summer coat i s also characterized by the lack of the woolly undercoat. Thus there i s opportunity for greater a i r c i r c u l a t i o n over body, and presumably greater opportunity for d i s s i p a t i o n of body heat. Hairs on the lower legs are longer on the forward surface than elsewhere. In the v i c i n i t y of the t a r s a l and metatarsal gland 95 the hairs are rougher and coarser. The hairs occurring on the underside of the t a i l , posterior side or the rump and i n periphery of the urogenital area as well as i n a x i l l a and inguinum, are long and white. The t a i l c a r r i e s a black spot d o r s a l l y . Moult from adult summer to adult winter-coat This takes place during l a t e summer to early autumn and l a s t s from August to October. The general d i r e c t i o n i s from head towards t a i l i . e . cauded. The moult i s f i r s t noticed i n the ears, which dorsa l l y bear a very t h i n coat of h a i r . A thicker coat grows i n i t s place and the pinnae are f u l l y covered. The next region to moult i s head. The loss of hairs on the face i s d i f f u s e , but where the hairs are longer on the head the moult t r a c t s appear; One of these moves upwards through the region between the eyes and the ear pinnae and touches the dorsal side of the neck. The other t r a c t moves sidewards along the cheek t i l l i t meets the neck. The loss of hairs on the lower jaw also takes place about t h i s time but i s d i f f u s e . On the neck the shedding continues along the side, and undersurface. The summer hairs present d o r s a l l y i n the neck region undergo a gradual thinning and are amongst the l a s t summer hairs to be shed. While the neck i s l o s i n g hairs the shoulders and the ante-r i o r region of the back also begin to shed. On shoulders the thinning begins i n the central region and gradually spreads out to meet the neck, back, flanks and chest region. The hair shedding on the shoulder area continues onto the flank region i n a diagonal manner and proceeds towards the abdomen. Simultaneously hair loss FIGURE 35 Adult i n summer coat. Moult from adult summer coat to adult winter coat FIGURE 3 6 . 1 Moult stage I. The ears have moulted. FIGURE 36.2 Moult stage I I . Moult progressing cauded, The body i s moulting. FIGURE 36 .3 Moult stage I I I . Only the d i s t a l end of legs remain to be moulted. 97 FIG. 35 FIG. 36.1 STAGE I FIG.36.2 STAGE 2 FIG. 36.3 STAGE 3 FIG. 36 ADULT SUMMER TO ADULT WINTER MOULT STAGES 98 on the back i s progressing steadily caudad. The summer hairs on the upper side of the flanks are also shed about t h i s time (late August) and a stage i s reached when the summer hairs on the body remain i n the region of the chest, abdomen, the limbs and posterior part of the back. The wave of moult now proceeds from the shoulders, f i r s t along the front of the foreleg, then to the posterior face and toward the hoof where i t i s di f f u s e and gradual. This takes place i n September. The loss of summer hairs i n the chest region takes place i n l a t e August. The shedding proceeds between the forelegs towards the abdomen where again moult becomes d i f f u s e . In early August the central part of thighs begin to shed h a i r s . This patch enlarges to meet do r s a l l y the back and l a t e r a l -l y the flanks. The posterior margin of t h i s patch i s demarcated by the elongated hairs i n the rump region, which are amongst the l a s t to be shed. D i s t a l l y i n the hind leg moult d i f f e r s from that of the fore legs as i t proceeds along the sides leaving the summer hairs more or le s s i n t a c t i n the front part and also i n the posterior margin and i n the area surrounding t a r s a l and metatarsal glands and around hooves. The loss of hair i n these places i s very gradual and d i f f u s e and may continue even into early October. The long white hairs on the rump are shed gradually from the v i c i n i t y of the feail downwards i n early September. The white hairs bordering the anal and urogenital area are shed e a r l i e r than those of the posterior margin of rump and here the trend of shed-ding i s ventrad. 9 9 The shedding of the hairs on t a i l i s di f f u s e and appears to take place during summer. By f a l l the t a l l has new h a i r s . Adult winter coat The winter coat of the black t a i l i s much denser than the summer coat because there i s well developed woolly undercoat. In contrast to the reddish yellow tinge of the summer coat i n i t s early stages presents a sleek metallic grey appearance (October), but soon fades to a paler shade. The forehead region i s demarcated on i t s sides by two dark l i n e s which descend and meet i n between the eyes. The presence of greyish hairs around the eyes and i n front of the snout give a d i s t i n c t mask l i k e appearance present only i n the winter coat. The hair colouration varies but the hair types except for the wool f i b r e s and th e i r d i s t r i b u t i o n on the body are as i n summer. The i n d i v i d u a l hairs however have large diameter and a length r e l a t i v e l y shorter (refer to l a t e r tables) than that i n the summer coat. The kemps are more wavy i n form. The percentage of short hairs i s greater than i n summer coat. The wavy nature of kemps a s s i s t s i n accommodating the woolly undercoat properly — both together constituting a good ins u l a t i n g layer dn the body i n winter. Moult from adult winter coat to adult summer coat At our l a t i t u d e t h i s moult begins i n mid-April and ends by lat e June and follows a pattern d i f f e r e n t from that of the f a l l moult. Generally the flanks are the f i r s t to shed, and patches having new summer coat are formed on both sides. This culminates Adult winter to adult summer coat moult FIGURE 37 Adult i n winter coat. FIGURE 38.1 Moult stage I. The moult s t a r t s on the body. FIGURE 38.2 Moult stage I I . Moult spreads cephalad and caudad. FIGURE 38.3 Moult stage I I I . Moult complete except f o r patch under the throat, and some hairs on hind leg d i s t a l end. 101 FIG. 38.2 STAGE 2 FIG. 38.3 STAGE 3 FIG. 38 ADULT WINTER TO ADULT SUMMER MOULT STAGES 102 i n a stage when the animals appear to have moulted c e n t r a l l y along the flanks and to some extent d o r s a l l y . The shedding of short hairs on the face as well as on the d i s t a l ends of legs i s taking place d i f f u s e l y . The new hairs are of the same colour as the old hairs and have already grown to some length "before the old hairs are shed. The flank moult i s completed by early June. On the body the moulting now proceeds i n two directions — cephalad along the neck and caudad along the rump. Along the neck the hairs are f i r s t l o s t on the dorsal and l a t e r a l sides and those on the lower side are amongst l a s t to be shed. This occurs i n June. P o s t e r i o r l y on the thighs the hairs are shed and moult-ing proceeds downwards. The winter hairs on the posterior margin of the rump are among the l a s t to shed and are moulted ventrad. The hairs around the anal and urogenital region moult e a r l i e r than t h i s (mid-June). The abdomen moults d i f f u s e l y i n May. Hairs on the posterior margin of the hind limbs and across the t a r s a l and metatarsal glands are again the l a s t to be shed. In early June the ears also shed t h e i r hairs and during the re s t of summer coat they are covered sparsely by small hairs giving the pinnae a bare appearance. Gross inspection of the ears reveal a r i c h blood supply and i t i s tempting to suggest that they are important i n thermoregulation. I f t h i s i s so the almost naked condition i n summer and heavily furred state i n winter has adaptive s i g n i f i c a n c e . 103 Summary The major pelage types i n the l i f e h istory of the black t a i l deer have been investigated and the process of moulting from one type into another has been documented. The hairs of t h i s species can be distinguished as follows: large guard hai r s , intermediate guard hairs, and beard type (long and soft guard hairs i n Odocolleus r e s t r i c t e d only to t a i l ) . These a r i s e i n primary f o l l i c l e s . The f i r s t formed secondary f o l l i c l e s give r i s e to small but medullated hairs i . e . of t r a n s i -t i o n a l type and the l a t e r formed secondaries to the non medullated woolly under hairs — forming the animals undercoat. The f i r s t formed secondaries and some primaries produce sp e c i a l medullated hairs; with well developed proximal end but t h i n and wavy d i s t a l end. These have been c a l l e d t r a n s i t i o n a l types. They i n fac t constitute the undercoat i n fawn b i r t h coat. In addition primary f o l l i c l e s i n the fawn b i r t h coat at places give r i s e to white tipped h a i r s . Thus the primary f o l l i c l e s are capable of giving r i s e to many hair types. The hair scale c h a r a c t e r i s t i c s depend on hair dimension and not on hair type. They seem to be vary c l o s e l y with the hair diameter. The woolly under hair present a v a r i a t i o n of coronal scale type; and are of uniform diameter. The guard hair diameter i s however greatly v a r i a b l e . Their scale pattern varies from Irregular mosaic to ir r e g u l a r waved mosaic with smooth margins and the intermarginal distance varying from distant, intermediate (close), to near. The adult winter coat hairs :present greater v a r i a b i l i t y i n scale pattern. 104 The hairs of fawn b i r t h coat resemble- those of adult summer coat i n colouration. The fawn winter coat possesses true woolly-undercoat, Snd resembles adult winter coat. The adult summer coat hairs are longer, stralghter and les s crimpy than the winter coat h a i r s . It lacks woolly undercoat and has a c h a r a c t e r i s t i c colouration. The adult winter coat hairs are shorter, thicker and darker. There i s also greater v a r i a b i l i t y i n t h e i r length. The pelage colouration depends on the colouration of the v i s i b l e extremities of guard h a i r s . These as well as other morphometric d e t a i l s of hairs have been covered i n a separate chapter. The black t a i l deer moults twice a year i . e . i n spring and again i n l a t e summer to early autumn. The fawn b i r t h coat begins to be shed by July and the fawn winter coat i s assumed by October. The b i r t h coat moult takes place i n d i s t i n c t i v e stages and the trend i s caudad. White spots are l o s t early. The spring moult of yearlings ( i . e . fawn winter to adult summer coat) could not be observed. The adult winter moult begins on the flanks and spreads both cephalad and caudad. The shedding of the summer coat i s caudad. The woolly undercoat of non medullated hair moults i n dif f u s e fashion only once a year i . e . i n May. 105 Chapter V THE HAIR CYCLE OF THE BLACK TAIL DEEH  INTRODUCTION The moult i s only a terminal stage of the hair cycle and to appreciate the phenomenon of hair replacement properly the annual hair cycle i n i t s e l f has to be c l e a r l y understood. The s i g n i f i -cance of t h i s has been adequatly stressed by Ling (19&5)» and by Ryder (1964). The best way to do t h i s i s to sample the skin at regular i n t e r v a l s and record the changes i n the hair f o l l i c l e i n the course of the year. Nothing i s known of t h i s phase of the seasonally c y c l i c a l biology of any c e r v i d . MATERIAL AND METHODS Two animals were used for t h i s study and skin biopsy samples were c o l l e c t e d every fortnight by means of trephine. The d e t a i l s of the trephine have been discussed by Ling (1965). The animals were immobilized by using Succinylcholine chloride (ANECTINE). The dosage f o r deer was worked out by Zoology Dept. i n course of e a r l i e r research and was .0013 cc/lb of animal weight. As the animals were weighed every week correct dosage could be administered while sampling. The dosage was administered by tuberculin syringe, using disposable needles. The response i n the animal was variable,. W9 i n p a r t i c u l a r often had d i f f i c u l t y breathing a f t e r collapsing on the ground and often required a r t i f i c i a l r e s p i r a t i o n . Subsequent manipula-t i o n of the dosage revealed that even $0% of prescribed dosage FIGURE 39 The trephine used for taking skin biopsy sampling. FIGURE 40 Fortnightly sampling s i t e s . The number denotes the "sample" number as well as i t s l o c a t i o n on the animal's body. FIG 39 1 5 9 13 17 4 15 19 23 27 22 8 II 25 30 29 26 12 7 21 28 24 20 16 3 18 14 10 6 2 FIG 40 1 0 8 was s u f f i c i e n t to Immobilize t h i s i n d i v i d u a l and the dosage was modified accordingly. For the other animal regular dosage did not create problems. A sampling programme was also drawn up to ensure that successive sampling s i t e s were not adjoining each other. Samples were taken from the thigh, and f i x e d i n BOUIN'S f l u i d , and stored i n 70% a l c o h o l . Subsequently each sample was divided into two equal parts. One part was sectioned l o n g i t u d i n a l l y i . e . perpen-di c u l a r to the surface, along the plane of the hairs and the other part was sectioned across the surface. The sections cut at 8 / ^ were stained with haematoxylin and eosin. OBSERVATIONS On the thigh the main body pelage consists of three types of h a i r s . The large and intermediate guard hairs and the woolly under h a i r s . In adult animals a l l growing central primary f o l l i -c l e s are of approximately the same length and there i s less length v a r i a t i o n than i n these hairs i n the natal pelage. The f o l l i c l e s i n a l l species studied assume the following stages during the hair cycle. The phase during which the f o l l i -c l e i s formed and the new hair i s produced has been termed the anagen. This envolves transformation of the r e s t i n g f o l l i c l e into an a c t i v e f o l l i c l e . The f o l l i c l e base i s clavate and encloses the dermal p a p i l l a while the r e s t of the newly forming f o l l i c l e s can be distinguished into an external root sheath and a central mass of undifferentiated c e l l s . Subsequently a l l the normal layers are d i f f e r e n t i a t e d and the f o l l i c l e s t a r t s produc-ing new h a i r . When the f o l l i c l e has reached i t s f u l l period of 109 growth i t enters into catagen stage. This i s a t r a n s i t i o n a l short l i v e d period, leading to the r e s t i n g stage of the f o l l i c l e , namely telogen. In catagen the bulb becomes collapsed and the dermal p a p i l l a i s not t i g h t l y held by the f o l l i c l e base. The hair base forms a club enclosed i n a sac of external root sheath and the portion of the f o l l i c l e below i t degenerates into a strand of c e l l s . The hair and the f o l l i c l e part remaining migrate upwards t i l l they reach sebaceous gland l e v e l , where they remain. This i s the telogen or r e s t i n g stage. During subsequent hair cycle the f o l l i c l e w i l l be reactivated, old hair shed and by a r e p e t i t i o n of process already described new hair w i l l be produced. A l l the f o l l i c l e s discussed here undergo these stages but due to the very short nature of i t s duration catagen has not been observed f u l l y here. To understand the events involved i n the hair cycle of my animals l e t us begin with the winter coat i n the r e s t i n g stage. The winter coat attains f u l l growth by early November and reaches r e s t i n g stage then. The h i s t o l o g i c a l examination of the material reveals that by early March the guard hair f o l l i c l e s have started growing, the large guard hair f o l l i c l e s presumably s t a r t i n g f i r s t , and possess the f i r s t emergent summer coat h a i r s . These are scattered a l l over the body, reaching lengths which makes them protrude i n A p r i l over the e x i s t i n g winter coat. The summer coat guard hairs emerge i n mass f i r s t on the flanks and then continue emerging towards neck and the posterior end. The large guard hairs of winter coat are shed i n A p r i l and the pelage at t h i s stage consists of re s t i n g winter coat interme-diate guard hairs and woolly under hairs, plus a c t i v e l y growing Guard hairs FIGURE 4 1 . 1 Deer f o l l i c l e . Notice the shape of dermal p a p i l l a and the inner root sheath c e l l layers and melanin deposition i n cortex. H. & E. FIGURE 4 1 . 2 Deer secondary f o l l i c l e . Notice the external root sheath, c e l l o rientation as well as the membrane. H. & E. FIGURE 42 Guard h a i r f o l l i c l e s i n catagen. Growth has ceased and the f o l l i c l e i s withdrawing. H. & E. FIGURE 4 3 . 1 Base of f o l l i c l e i n telogen. Notice the with-drawn f o l l i c l e base and rounded dermal p a p i l l a and the r e s t i n g h a i r . Notice p o s i t i o n of sweat gland and the r e s t i n g f o l l i c l e . H. & E. FIGURE 4 3 . 2 Close up of r e s t i n g f o l l i c l e . Notice the p a r t i a l l y enclosed rounded dermal p a p i l l a . H. & E. For explanation of abbreviations used please see Appendix, Page 2 1 4 . I l l 112 summer coat guard h a i r s . Intermediate guard hairs f i r s t emerge by mid-March and large guard hairs by early March. By l a t e March a l l guard hair f o l l i c l e s are vigorously growing and winter coat intermediate guard hairs are s t i l l r e s t i n g . The f i r s t formed secondary f o l l i c l e s which give r i s e to medullated hairs were also noticed growing i n March. These f o l l i -c l e s have emergent hairs i n A p r i l . The f o l l i c l e at t h i s time contains an emergent hair plus the old r e s t i n g h a i r s . By mid-May some of the smaller intermediate guard hairs are reaching r e s t i n g stages and by la t e June a l l hairs are i n re s t i n g stage. The larger guard hair f o l l i c l e s coming to res t l a s t . The f i r s t formed secondaries are also i n r e s t i n g stage now and animal i s i n f u l l y formed summer coat. By mid-July the f i r s t formed secondaries s t a r t growing again. By the end of July a l l secondaries are a c t i v e l y growing woolly h a i r s . The previous year's woolly hairs had been l o s t i n May without any regenerative a c t i v i t y i n t h e i r f o l l i c l e s . The guard hair f o l l i c l e s are also s t a r t i n g to grow and by early August the winter coat hairs have emerged on the surface. They make t h e i r way through the growing woolly hairs and overtake them i n growth rate . By October end a l l winter coat guard hairs are re s t i n g . The intermediate guard hairs come to r e s t and then the l a s t guard h a i r s . The f i r s t formed secondary f o l l i c l e s are also r e s t i n g by October. By December a l l woolly under coat hairs are r e s t i n g . Thus l a t e r formed secondary f o l l i c l e s have a longer growing period. The guard hair f o l l i c l e s and woolly under hair f o l l i c l e s continue to r e s t t i l l March and July respectively when they s t a r t growing again. FIGURE 4 3 . 3 Dermal p a p i l l a i n telogen close up. Longitudinal section. H. & E. FIGURE 4 3 . 4 Close up of spatulate dermal p a p i l l a of guard h a i r . Longitudinal section. H. & E. FIGURE 4 3 . 5 New hair growing beside old r e s t i n g h a i r . Notice the p o s i t i o n of arrector p i l i i muscle. Longitudinal section. H. & E. FIGURE 4 3 . 6 Transverse section of 4 3 . 5 above. H. & E. For explanation of abbreviations used please see Appendix IV, Page 214. 114 115 Summary Guard hairs of both coats of the adults have a 3 1/2-month growth period. However summer pelage i s i n a rest i n g state on the body for two months and the winter pelage for f i v e months. The large guard hairs s t a r t growth early but come to res t l a s t . The f i r s t formed secondaries also appear to shed t h e i r hairs twice, and thus behave l i k e primaries. The l a t e r formed secondaries have a 5^/2-month grossing period and a 6^/2-month res t i n g period. They are l o s t i n May by being broken off at the surface of the skin. Thus though absent from the functional summer coat, th e i r stubs are present i n the f o l l i c l e s . These are shed i n mid-July when these f o l l i c l e s start growing and producing new hair again. 116 TABLE 3 Annual Cycle of the Black T a l l Deer A c t i v i t y Duration Prom To Summer coat grows F i r s t March Mid-June Summer coat rests Mid-June Mid-August F o l l i c l e r e s t s Mid-June Mid-July Summer coat sheds Mid-August October Winter coat grows Mid-July October Winter coat rests November A p r i l Winter coat sheds May June Woolly under coat grows Mid-July December Woolly under coat r e s t s January Mid-July Woolly under coat sheds May Mid-June FIG.44 DIAGRAMATIC REPRESENTATION OF THE ANNUAL HAIR CYCLE 117 Chapter VI THE MORPHOMETRY OF BLACK TAIL HAIRS  INTRODUCTION As shown i n Chapter IV, the deer a l t e r s i t s pelage char-a c t e r i s t i c s between youth and maturity and also between summer and winter, each year of i t s l i f e . I t i s assumed that the succession of pelage and also the d e t a i l s of the hairs themselves develop i n response to genetic instructions that are es s e n t i a l components of the entire catalogue of such that govern the form and function of the animal. I have described the f o l l i c l e s from which the several types of hairs a r i s e and given a general description of each type, the features of the coat of which they constitute a part and the moult patterns that these coats follow. It i s important however to est a b l i s h i n more d e t a i l the differences that d i s t i n g u i s h the h a i r types and the seasonal changes they undergo amidst conditions close to the optimum. Only with such d e t a i l s i n hand can a l t e r -ations a r i s i n g from environmental impact or a l t e r a t i o n s associ-ated with species or geographic areas be studied. MATERIAL AND METHODS To est a b l i s h the v a r i a t i o n i n the d i f f e r e n t coat types, i n regions within these coat types and i n hair types within these regions, guard hair samples were selected on random basis from f i v e selected regions. These were: 118 1) Back 2) plank 3) Abdomen 4 ) Thigh 5 ) Hind l e g . D i s t a l end. The samples were sorted out into large and intermediate guard hairs and were measured for length and diameter. The d i f f e r -ent coloured bands present on the hairs were also measured. The data so c o l l e c t e d was s t a t i s t i c a l l y analysed i n an I.B.M. 704-0 computer with the help of programmes available from the Faculty of Forestry. These analyses were of two kinds. A) For the study of v a r i a t i o n i n length, diameter and colour zone i n d i f f e r e n t coats, regions and type of h a i r . B) For the study of c o r r e l a t i o n between the length and diameter i n the hair under d i f f e r e n t circumstances. For the f i r s t kind of study a nested (within) analysis of variance of lengths of hair was done. Similar analysis was under-taken for the measurements of diameter of the h a i r s . In addition the proportion of the t o t a l length of the hair under each of the four colour zones was computed and a s i m i l a r separate analysis of variance done fo r each zone. The r e s u l t s are summarized below. OBSERVATIONS Length The length measurements taken are given i n Table 5« The r e s u l t s of analysis of variance are given i n Table 4 . 119 TABLE 4 Nested Analysis of Variance Hair Length Source Degree of freedom Sum square Mean square F Coat 3 31431.00 10477.00 318.73** Region within coat 16 109130.00 6820.70 207.56** Type within region within coat 20 71055.00 3552.80 108.08** Error 660 21694.00 32.87 Total 699 233310.00 As the 'F' values are highly s i g n i f i c a n t Duncan's multiple range test L i , (1964) was performed f o r the coat means, regions within coat means and type within region within coat means. The re s u l t s are tabulated i n Table 6, where two or more means are underscored by the same l i n e i t denotes that they are not s i g n i f i c a n t l y d i f f e r e n t from each other at 5$, significance l e v e l . Other apparent differences are s i g n i f i c a n t . To understand whether the hair types /region/ coat are or are not s i g n i f i c a n t l y d i f f e r e n t from each other i n respect of the pa r t i c u l a r parameter under consideration, r e f e r to Table 5« The underscoring of figures where present implies that the hair types are not s i g n i f i c a n t l y d i f f e r e n t i n respect of the parameter i n question, as tested by Duncan's multiple range t e s t . On perusal of the data i n r e l a t i o n to the hair length the following points emerge. The large guard hairs and the intermediate guard hairs are consistently d i f f e r e n t i n length. Only i n region f i v e of the BIRTH FIG. 4 5 FAWN3 WINTER ADULT SUMMER ADULT WINTER COAT TYPES GUARD HAIR LENGTH RELATIONSHIP IN DIFFERENT COATS OF BLACK TAIL DEER; WITH THEIR MAJOR HAIR COLOUR ZONES H o TABLE 5 Lengths of Hair Samples i n mm Hair type 1 Hair type 2 (Large guard) (Intermediate guard) No. of No. of Mean length & No. of Coat type Region Length (mm) Observation Length i n mm 1 Observation Observations Coat I 1 46.1875 16 21.8696 23 31 .8462(39) 2 58.2308 13 30 .8824 17 42.7333(30) (Birth coat) 3 44.0000 11 18.7200 25 26.4444(36) 4 41.9333 15 23 .8400 25 30.6250(40) 5 15.8000 10 11.9545 22 13.1563(32) Average 28.9379(177) Coat II 1 56.0000 11 39.2000 25 44.3333(36) 2 59.0000 6 37.0000 26 41.5313(32) Fawn winter 3 51 .6364 11 32 .0417 24 38.2000(35) coat 4 55.8750 16 34.9630 27 42.7442(43) 5 13.7143 14 I I .3125 16 12.4333(30) Average 36.7784(176) Coat III 1 76.6923 13 43.0000 25 54.5263(38) 2 79.0769 13 46.9583 24 58.2432(37) Adult summer 3 70 .1429 14 38.7600 25 50.0256(39) coat 4 73.0000 13 47.0000 25 55.5947(38) 5 23.3077 13 12.7917 24 16 .4865(37) - ... • Average 47.1536(189) Coat IV 1 58.1818 11 43.2083 24 47.9143(35) 2 58.3333 12 44.8400 25 49.2162(37) Adult winter 3 49.5556 9 43.3636 11 46.1500(20) coat 4 58.1111 9 39.4400 25 44.3824(34) 5 21.3750 8 11.8333 24 14.2188(32) Average 40 .4114(158) 122 TABLE 6 Duncan's Multiple Range Test Hair Length i n millimeters A Within coats Coat III IV II I Mean length 47.15 40 .41 36.78 28.94 B Regions within coats Coat I Region 2 1 4 3 5 Mean length 42.73 30.63 26.44 13.16 Coat II Region 1 4 2 3 5 Mean length 44.33 42.74 38.20 12.43 Coat III Region 2 4 1 3 5 Mean length 58.24 55.89 54.52 50.03 16.49 Coat IV Region 2 1 3 4 5 Mean length 49.22 47.91 4 6 . 1 5 44.30 12.22 C - The hair types within regions see Table 5 123 fawn b i r t h coat and fawn winter coat are these differences s t a t i s t i c a l l y not s i g n i f i c a n t . The hairs i n region f i v e of a l l the coats were considerably smaller i n length than those i n the other regions sampled. Amongst the regions sampled f o r length, the hairs on flanks (region two) were observed to be the longest. The increases i n hair length can be attr i b u t e d either to faster rate of growth or to longer duration of growth or both. No observations i n thi s respect are available i n r e l a t i o n to the d i f f e r e n t body regions of the black t a i l deer. It may be of interest to investigate hair growth over d i f f e r e n t body regions of the same animal over a period of time and esta b l i s h presence of growth gradients i f any. The hair length also increases from fawn b i r t h coat onward to adult summer coat but decreases again i n the adult winter coat. Diameter The diameter measurements taken are shown i n Table 8 and the r e s u l t s of the analysis of variance are given i n Table 7« TABLE 7 Nested Analysis of Variance Hair Diameter Source Degree of freedom Sum square Mean square Coat Region within coat Type within region within coat Error Total 3 16 20 660 699 1977300.OO 659100.00 819.88** 1065400.00 66587.OO 82 .83** 358400.00 17920.00 22.29** 530570.00 393700.00 803.90 1 2 4 As the 'F' values are highly s i g n i f i c a n t Duncan's multiple range test L l ( 1 9 6 4 ) was performed for the coat means, regions within coat means, and the hair type within region within coat means. The r e s u l t s are tabulated i n Table 9 . Where two or more means are underscored by the same l i n e i t denotes that they are not s i g n i f i c a n t l y d i f f e r e n t from each other at $% significance l e v e l . To understand whether hair types /region/ coat are or are not s i g n i f i c a n t l y d i f f e r e n t from each other i n respect to diameter ref e r to Table 8 . Figures underscored indicate that the hair type i n question are not s i g n i f i c a n t l y d i f f e r e n t i n respect of t h i s parameter (diameter), as tested with Duncan's multiple range t e s t . In respect to hair diameters the following can be said. In the fawn b i r t h coat the diameters of large guard hairs and i n t e r -mediate guard hairs are not s i g n i f i c a n t l y d i f f e r e n t but i n subse-quent coats generally the large guard hairs, though of greater length, possess smaller diameters than the comparable intermediate guard h a i r s . The consistent exceptions to t h i s have been i n region f i v e of a l l the four coats and also regions one and two of three and region one of coat four. In the fawn b i r t h coat and fawn winter coat the greater / diameter i s attained by hairs i n the flank region. But i n the adult summer and winter coats i t was the abdominal hairs which c h a r a c t e r i s t i c a l l y attained the largest diameters. The average diameter for the pelage continues to increase from fawn b i r t h coat onwards t i l l the adult winter coat stage i s reached. Thus winter hairs are of larger diameter than the summer ha i r s . BIRTH FAWN WINTER A D U L T S U M M E R ADULT W INTER COAT TYPES F IG.46 GUARD HAIR D IAMETER RELATIONSHIP IN D I F F E R E N T B L A C K T A I L C O A T S TABLE 8 Diameter of Hair Samples i n Microns Type 1 Type 2 Body No. of No. of Mean Coat type Region Diameter Observations Diameter Observations Diameter Coat I 1 6 0 . 3 7 5 0 1 6 57 .3478 2 3 58.5897(39) 2 62.9231 1 3 72.8824 1 7 6 8 . 5 6 6 7 ( 3 0 ) B i r t h coat 3 50.8182 11 56 .4400 2 5 54.7220(36) 4 73.1333 1 5 75 .7200 2 5 74.7500(40) 5 65.9000 10 62.9545 22 6 3 . 8 7 5 0 ( 3 2 ) Average 64.1017(177) Coat II 1 99.6364 11 152 .6400 2 5 136 .4444(36) 2 108.0000 6 177.6538 26 1 6 4 . 2 1 8 8 ( 3 2 ) Fawn winter 3 117.3636 11 142.1250 24 134.3429(35) coat 4 1 1 6 . 3 1 2 5 1 6 156 .0741 27 141.2791(43) 5 8 4 . 3 ^ 1 14 85 .8125 1 6 8 5 . 1 3 3 3 ( 3 0 ) Average 1 3 3 . 5 1 1 ^ ( 1 7 6 ) Coat III , 1 150.3077 1 3 143.8400 2 5 146.0526(38) 2 174.2308 1 3 170.1667 24 1 7 1 . 5 9 4 6 ( 3 7 ) Adult summer 3 1 5 3 . 4 2 8 6 14 2 2 7 . 8 8 0 0 2 5 201.1538(39) coat 4 1 5 5 . 3 0 7 7 1 3 187.8800 2 5 176.7368(38) 5 9 9 . 0 7 6 9 1 3 113.0000 24 108.1081(37) Average 161 .1 6 4 0 ( 1 8 9 ) Coat IV 1 200 .4545 11 213 .4167 24 209 .3429(35) 2 194.8333 12 261.4400 2 5 2 3 9 . 8 3 7 8 ( 3 7 ) Adult winter 3 2 3 8 . 6 6 6 7 9 3 8 7 . 0 9 0 9 11 3 2 0 . 3000 ( 2 0 ) coat 4 I63.OOOO 9 273 .2800 2 5 244.0882(34) 5 76 . 0000 8 96 . 3750 24 9 1 . 2 8 1 3 ( 3 2 ) Average 214.0949(158) 127 TABLE 9 Duncan's Multiple Range Test Hair Diameter i n microns A Within coats Coat IV III II I Mean diameter 214^09 161.16 1 3 3 . S i 64.10 B Regions within coats Coat I Region 4 2 5 1 3 Mean diameter 74.75 68 .56 6 3 . 5 7 58.58 54.72 Coat II Region 2 4 1 3 5 Mean diameter 164.21 141.27 136.44 134.34 85.13 Coat III Region 3 4 2 1 5 Mean diameter 201.15 176.73 171.59 146.05 108.10 Coat IV Region 3 4 2 1 5 Mean diameter 320.30 244.08 239.83 209.34 91 .28 C Hair type within region r e f e r to Table 8 128 Colouration The colouration of the coats d i f f e r greatly, p a r t i c u l a r l y between the summer and winter pelages. The summer coats are reddish-yellow while the winter coats are greyish. The fawn b i r t h coat and adult summer coat have similar general colouration of hairs but subtle differences do e x i s t . The yellow coloured zone which follows the black t i p i s short, but present i n the adult summer coat while i t i s t o t a l l y absent i n the fawn b i r t h coat. The presence of white spots on the fawn b i r t h coat i s also very c h a r a c t e r i s t i c . The fawn winter coat i s also a l i t t l e darker than the adult winter coat, as some of the guard hairs i n i t are completely black, p a r t i c u l a r l y on the back and sides. The d i f f e r -ent colour bands on an agouti pattern hair represent pulses of a c t i v i t y i n pigment production by the f o l l i c l e . S u p e r f i c i a l study of hairs present i n the d i f f e r e n t pelages of t h i s deer led us to the impression that these pulses, and the r e s u l t s as seen i n the pigmentation of the hair, d i f f e r e d within the d i f f e r e n t pelages, as well as between body regions. To explore t h i s i n more d e t a i l appropriate samples of hair were subjected to detailed measurement of the lengths of each of four colour segments, black, yellow, grey (or reddish-yellow), and white (colourless). Black coloured zone In the regions sampled the t i p of the hair i s black. This i s also true for abdominal h a i r s . This zone was longer i n the back region of the fawn b i r t h coat but attained i t s maximum extent i n some hairs of the back i n fawn winter coat. Generally the large guard hairs have greater proportion of t h i s black 100 A BIRTH FAWN ADULT ADULT WINTER SUMMER WINTER. COAT TYPES FIG.47 PERCENTAGES OF DIFFERENT COLOURED ZONES IN COAT H TYPES IN RELATION TO TOTAL HAIR LENGTH , A = BLACK, £ B = YELLOW, C= REDDISH YELLOW, D= GREY , E = WHITE TABLE 10 Black Coloured Zone Hair type I Hair type II Black colour No. of Black colour No. of Mean & No.of Coat type Region zone Observations zone Observations Observations Coat I 1 0 .3993 16 0.2167 23 0.2916(39) 2 0 .1385 13 0.1260 17 0.1314(30) 3 0.2307 11 0.04-50 25 0.1017(36) 4 0.1711 15 0 .1044 25 0.1294(40) 5 0.0941 10 0.0874 22 0.0895(32) Average 0.1526(177) Coat II 1 0.6751 11 0.1258 25 0.2936(36) 2 0 .1182 6 0.0964 26 0.1005(32) 3 0.0384- 11 0.0721 24 0.0615(35) 4 0 .1286 16 0 .0812 27 0.0989(43) 5 0 .0828 14 0.0889 16 0 .0861(30) Average 0.1294(176) Coat III 1 0.1522 13 0.1269 25 0.1355(38) 2 0 .0924 13 0 .07?8 24 0.0843(37) 3 0.0575 14 O.O878 25 0.0770(39) 4 0 .1114 13 0.1021 25 0.1053(38) 5 0.0732 13 0.1037 24 0.0930(37) Average 0.0990(189) Coat IV 1 0.0303 11 0 .0969 24 0.1074(35) 2 0.1432 12 O.O656 25 0.0908(37) 3 0.1633 9 0.0604 11 0.1067(20) 4 0.1538 9 0.0706 25 0.0926(34) 5 0.0853 8 0.0851 24 0.0851(32) Average 0.0957(158) 131 coloured zone, than the intermediate guard hair types. Table 10 depicts the extent of t h i s region amongst the samples studied and also i d e n t i f i e s those not s i g n i f i c a n t l y d i f f e r e n t from each other (underlined f i g u r e s ) . Taking the average for the coats, i t i s found thatvthe black coloured region has maximum extent (15% of t o t a l h a i r length) i n fawn b i r t h coat and decreases consis-t e n t l y t i l l i t attains a l e v e l of 9% i n adult winter coat. TABLE 11 Nested Analysis of Variance. Black Coloured Region Degree Sum Mean Source of freedom square square P Coat 3 0.38033 0.12678 66.38** Region within coat 16 2.3570 0.14731 77.13** Type within region 20 3.1390 0.15695 82.18** within coat Error 660 1.2605 .0019098 Total 699 7.1368 As the 'F* values are highly s i g n i f i c a n t Duncan's multiple range test was performed f o r the coat means, region within coat means and type within region within coat means. The r e s u l t s are tabulated i n Table 12. Where two or more means are underscored by the same l i n e i t denotes that they are not s i g n i f i c a n t l y d i f f e r e n t from each other at 5% significance l e v e l . 1 3 2 Table 12 Duncan's Multiple Range Test Black coloured region ( r a t i o of hair lengths) A Within coats Coat I II III IV Black colouration . 1 5 2 6 .1294 0.0990 0.0957 Region Black colouration Region Black colouration Region Black colouration Region Black colouration B Regions within coats Coat I 1 2 4 3 5 0.291600 0.131400 Q.129400 0.101700 O.895OO Coat II 1 2 4 5 3 0.293600 0.100500 0.098900 0.086100 0.061500 Coat III 1 4 5 2 3 0.135500 0.105300 0.093000 0.084300 0.077000 Coat IV 1 3 4 2 5 0.107400 0.106700 0.092600 0.908000 0.085100 C - Hair types within regions r e f e r to Table 10 1 3 3 Yellow coloured zone In a l l winter coats and to a small extent i n the i n t e r -mediate guard hairs from back of adult summer coat, a zone of yellow colouration l i e s below the black t i p . This zone i s completely missing i n the fawn b i r t h coat. It reaches i t s maximum extent i n adult winter coat. Regionally i t reaches i t s greatest extent i n region f i v e of the fawn winter coat. Table 1 4 . TABLE 13 Nested Analysis of Variance. Yellow Coloured Zone Degree Sum Mean Source of freedom square square P Coat 3 2 . 8 9 8 3 O.966II 7 1 0 . 1 0 * * Region within coat 16 4 . 9 2 9 6 0 . 3 0 8 1 0 2 2 6 . 4 6 * * Type within region 2 0 1 . 5 3 7 4 O.O76869 5 6 . 5 0 * * within coat Error 6 6 0 0 . 8 9 7 9 4 0 . 0 1 3 6 0 5 Total 6 6 9 1 0 . 2 6 3 As the 'F' values are highly s i g n i f i c a n t Duncan's multiple range test L l ( 1 9 6 4 ) was performed f o r the coat means, region within coat means and type within region within coat means. The r e s u l t s are tabulated i n Table 1 4 . Where two or more means are underscored by the same l i n e i t denotes that they are not s i g n i f i c a n t l y d i f f e r e n t , from each other at $% l e v e l of si g n i f i c a n c e . To understand i f any of the hair type /region/ coat are not s i g n i f i c a n t l y d i f f e r e n t i n respect of the parameter i n question (yellow colouration) see Table 1 4 . I f underscored the figures are not s i g n i f i c a n t l y d i f f e r e n t as per Duncan's multiple range test at 5% significance l e v e l . TABLE 14  Yellow coloured Zone Extent Hair Type I Hair Type II Yellow coloured No.of Yellow coloured No.of Mean & No.of Coat type Region Zone Observations Zone Observations Observations Coat I 1 0.0000 11 0.0000 23 0.0000(39) 2 0.0000 13 0.0000 17 0.0000(30) 3 0.0000 11 O.OOOO 25 0.0000(36) 4 0.0000 15 0.0000 25 0.0000(40) 5 0.0000 10 0.0000 22 0.0000(32) Average 0.0000(177) Coat II 1 0.0212 11 0.0556 25 0.0451(36) 2 0.0000 6 0.0961 26 0.0781(32) 3 0.0197 11 0.0000 24 0.0062(35) 4 0.0000 16 0.0378 27 0.0238(43) 5 0.4542 14 0.4348 16 0.4438(30) Average 0.1061(176) Coat III 1 0.0000 13 0.0357 25 0.0235(38) 2 0.0000 13 0.0000 24 0.0000(37) 3 0.0000 14 0.0000 25 0.0000(39) 4 0.0000 13 0.0000 25 0.0000(38) 5 0.0000 13 0.0000 25 0.0000(37) Average 0.0047(189) Coat IV 1 0.3126 11 0.1052 24 0.1702(35) 2 0.3761 12 0.0588 25 0.1617(37) 3 0.0000 9 0.0000 11 0.0000(26) 4 0.2440 9 0.0934 25 0.1333(34) 5 0.1080 8 0.2727 24 0.2315(32) Average 0.1511(158) 135 Duncan1 TABLE 15 s Multiple Range Test Yellow coloured zone A Within coats Coat I III II IV Yellow zone 0.000000 0.004700 0.106100 0.151100 B Regions within coats  .Coat I A l l figures are zero no s i g n i f i c a n t difference Coat II 3 4 1 2 5 0.006200 0.028300 0.045100 0.078100 0.443800 Coat III 2 3 4 5 1 0.000000 0.000000 0.000000 0.000000 0.023500 Coat IV 3 4 2 1 5 0.000000 0.133300 0.161700 0.170200 0.231500 Region Yellow coloured zone Region Yellow coloured zone Region Yellow coloured zone C Hair types within regions see Table 14 Grey or reddish-yellow coloured zone 136 This i s the next colour zone on the hair shaft. In winter coat i t i s grey and i n summer coat i t i s reddish-yellow. It i s c h a r a c t e r i s t i c a l l y of greater extent i n the abdominal region. This zone i s larger i n the fawn b i r t h coats and adult summer coats than i n the other pelages. The quantitative d e t a i l s of th i s region are given i n Table 1?. TABLE 16 Nested Analysis of Variance of Grey/.;Reddlsh-Yellow Zone Degree Sum Mean Source of freedom square square F Coat 3 2.6347 0.87825 104.57** Region within coat 16 7.6320 0.47700 56.79** Type within region 20 4.9701 0.24851 29.59** within coat Error 660 5.5431 0.0083986 Total 699 2.0780 As the ! F ' values are highly s i g n i f i c a n t Duncan's multiple range test L i (1964) was performed for the coat means, region within coat means, and type within region within coat means. The r e s u l t s are tabulated i n Table 18. Where figures have been under-scored by a l i n e i t means that they are not s i g n i f i c a n t l y different at $% l e v e l of s i g n i f i c a n c e . To f i n d out i f hair types within region within coat are s i g n i f i c a n t l y not d i f f e r e n t i n respect of parameter i n question (grey/reddish-yellow zone) see Table 17 underscored figures imply that they are not s i g n i f i c a n t l y d i f f e r e n t . TABLE 17 Grey or Reddish-yellow Zone Extent < Hair Type 1 Hair Type 2 Coat type Region Grey coloured zone or Reddish-yellow •No.of Observations Grey coloured zone or 'No.of Reddish-yellow Observations Mean & No.of Observations Coat 1 2 3 4 5 0 .5787 0 .8442 0.7453 0 .8043 0.S365 16 13 11 1 5 10 0.7477 0 .8484 0.9720 0.8537 0.8206 2 3 17 2 5 2 5 22 0 .6184(39) 0 . 8 4 6 6 ( 3 0 ) 0 . 9 0 2 7 ( 3 6 ) 0.8352(40) 0 . 8 2 5 6 ( 3 2 ) Average 0 .8146(177) Coat II l 2 3 4 5 0.2874 0.8390 0 .9223 0.8572 0.3893 11 6 11 16 14 O.7815 0 .7726 0 .895? 0 .8551 0.3879 2 | 2 6 24 2 7 16 0.6305(36) 0 . 1 8 5 0 ( 3 2 ) 0.9042(35) 0 .8559(43) 0 . 3 8 8 5 ( 3 0 ) Average 0.7269(176) Coat III l 2 3 4 5 0.8347 0.89^9 0 .9278 0 .8747 0.8803 1 3 1 3 14 1 3 13 0.8123 0.8986 0 .8717 0.8760 0 .8168 2 5 24 2 5 2 5 24 0 .8200(38) 0.8973(37) 0.8918(39) 6.8756(38) 0.8391(37) Average 0.8649(189) Coat IV 1 2 3 4 5 O.5368 0 .4362 0.8002 0.5675 0.7578 11 12 9 9 8 0 .7742 0.8528 0 .8849 0 .8204 0.5707 24 2 5 11 2 5 24 0 .6996(35) 0.7265(37) 0 .8468(20) 0 .7534(34) 0.6175(32) Average 0.7125(158) 138 TABLE 18 Duncan's Multiple Range Test Coat Grey/reddish yellow zone Grey/Reddish-yellow Zone A Within coats IV II I 0.719500 0.726900 0.814600 III 0.846900 B Region within coats Coat I 1 5 4 2 . 3 0.678400 0.825600 6.835200 0.846600 0.902700 Coat II 5 1 2 4 3 O.388500 0.630500 0.785000 0.855900 0.904200 Coat III 1 5 4 3 2 0.820000 0.839100 0.875600 0.891800 0.897300 Coat IV 5 1 2 4 3 0.617500 0.699600 0.726500 0.753400 0.846800 Region Grey/reddish yellow zone Region Grey/reddish yellow zone Region Grey/reddish yellow zone Region Grey/reddish yellow zone C Hair types within region see Table 17 139 White coloured zone (Translucent) This zone constitutes the basal stalk of the ha i r . The medulla i s missing i n th i s region and the c u t i c l e and cortex are translucent. This region i s c h a r a c t e r i s t i c a l l y longer i n the abdominal h a i r s . Considering the coats i t reaches i t s greater development i n the fawn b i r t h coat. The significance of i t ' s reaching greater extent i n abdominal hairs i s not c l e a r . It i s l i k e l y that medulla formation stops early i n th i s area and consequently a greater proportion of non medullated basal region i s formed. The explanation of early stoppage of medulla formation here i s locked i n the complex biochemical a c t i v i t y taking place within the hair f o l l i c l e s and needs further study. Where two of more means are underscored i t denotes that for the parameter i n question they are not s i g n i f i c a n t l y d i f f e r e n t from each other at l e v e l . To f i n d out i f any of the types within regions within coats are not s i g n i f i c a n t l y d i f f e r e n t r e f e r to Table 19. Figures underlined here are tested by Duncan's multiple range test and found to be not s i g n i f i c a n t l y d i f f e r e n t . TABLE 19  White Coloured Zone Hair Type I Hair Type II Coat type Region White coloured zone No. of Observations White coloured zone No. of Observations Mean & No.of Observations Coat I 1 0.0220 16 0.0467 23 .0366(34) 2 0.0173 13 0.0328 17 .0261(30) 3 0.0240 11 0.0550 25 .0455(36) 4 0.0246 15 0.0444 25 .0370(40) 5 0.0753 10 0.0920 22 .0808(32) Average .0458(177) Coat II 1 0.0181 11 0.0261 25 .0236(36) 2 0.0171 6 0.0276 26 .0256(32) 3 0.0197 11 0.0319 24 .0281(35) 4 0.0214 16 0.0219 27 .0262(43) 5 0.0753 14 0.0920 16 .0818(30) Average .035^(176 Coat III 1 0.0131 13 0.0236 25 0.0200(38) 2 0.0127 13 0.0216 24 0.0185(37) 3 0.0147 14 0.0522 25 0.0387(39) 4 0.0138 13 0.0219 25 0.0191(38) 5 0.0465 13 O.0795 24 0.0679(37) Average 0.0328(189) Coat IV 1 0.0173 11 0.0238 24 0.0217(35) 2 0.0174 12 0.0228 25 0.0211(37) 3 0.0405 9 0.0473 11 0.0442(26) 4 0.0173 9 0.0259 25 6.0236(34) 5 0.0490 8 0.0851 24 0.0761(32) Average 0.0358(158) l 4 l TABLE 20 Nested Analysis of Variance. White Coloured Zone Source Degree of freedom Sum square Mean square F Coat 3 0 . 0 1 7 5 8 0 . 0 0 5 8 5 9 9 8 0 . 7 4 * * Region within coat 1 6 0 . 2 9 1 2 1 .018201 2 5 0 . 7 6 * * Type within region within coat 2 0 0 . 0 5 7 9 6 2 .002898 3 9 . 9 3 * * Error 6 6 0 0 . 0 4 7 9 0 3 . 0 0 0 0 7 2 5 8 1 Total 6 9 9 0.41466 As the 'F' values are highly s i g n i f i c a n t Duncan's multiple range test L i ( 1 9 6 4 ) was performed for the coat means, regions within coat means and type within region within coat means. The re s u l t s are tabulated i n Table 2 1 . 142 TABLE 21 Duncan's Multiple Range Test White coloured zone .A Within coats Coat III II IV I White coloured zone 0.032800 0.035400 0.035800 0.045800 B Regions within coats Coat I ? 1 4 3 5 p.026100 0.036600 0.037000 0.045500 0.086800 Region White coloured zone Region White coloured zone Region White coloured zone Region White coloured zone Coat II 1 2; 4 3 5 0.023600 0.025600 0.026200 0.028100 0.081000 Coat III 2 4 1 3 5 0.018500 0.019100 0.020000 0.035700 0.067900 Coat IV 2 1 4 3 5 0.021100 0.021700 0.023600 0.044200 0.076100 C hair types within region see Table 19 Summary This chapter deals with morphometric observations on hairs i n respect of th e i r length, diameter and colouration ( i . e . pro-portion of the t o t a l hair length occupied by each of the colour zones). The data are based on observations on random samples of two hair types (large guard hair and intermediate guard h a i r ) . These hairs were studied i n the four coats ( i . e . each coat being treated as a whole). Comparative v a r i a t i o n was also studied i n respect of f i v e standard selected regions within each of the coats. Finally, the hair types within each region were i n v e s t i -gated and compared. Nested (within) analysis of variance was done on data obtained on hair length, hair diameter, and the d i f f e r e n t colour zones present on the hair shaft. The _'F' values obtained were highly s i g n i f i c a n t , i n d i c a t i n g that there was s t a t i s t i c a l l y s i g n i f i c a n t v a r i a t i o n between some of the aspects compared. To f i n d out the s t a t i s t i c a l significence of the i n d i v i d u a l values, Duncan's multiple range test was also done. The large guard hairs and the intermediate guard hairs are consistently d i f f e r e n t i n length. Only i n region f i v e of the fawn b i r t h coat and fawn winter coat are these differences not s i g n i f i c a n t . The hairs i n region f i v e of a l l the coats were considerably shorter than those i n the other regions sampled. Amongst regions sampled hairs were found to be longest on the flanks. The hair length increases from fawn b i r t h coat onward to adult summer coat but decreases i n the adult winter coat. In fawn b i r t h coat the diameters of large guard hairs and intermediate guard h a i r s are not s i g n i f i c a n t l y d i f f e r e n t , but 100 80 60 LU o CC LU °- 40 20 B o BIRTH FAWN WINTER ADULT SUMMER ADULT WINTER COAT TYPES FIG.48 PERCENTAGES OF DIFFERENT COLOURED ZONES IN VISIBLE PORTION OF PELAGE HAIR (ASSUMED TO BE 10 MM IN WINTER COAT AND 20MM IN SUMMER COAT) A = BLACK ,B = YELLOW, C =GREY , D= REDDISH YELLOW 1 4 5 LENGTH EXPOSED TO INCIDENT LIGHT SUMMER COAT (LONG) WINTER COAT (SHORT) FIG, 49 DIAGRAM RERRE i lNT INO POSITION OF OF GUARD HAIRS IN SUMMER COAT AND WINTER COAT 146 subsequently large guard hai r s , though of greater length, possess smaller diameters than comparable Intermediate guard h a i r s . The average diameter f o r the pelage continues to increase from fawn b i r t h coat onwards u n t i l adult winter coat stage i s reached. The winter hairs are of larger diameter than the summer h a i r s . In fawn b i r t h coat and fawn winter coat the greater diame-ter was noticed to be attained by hairs i n flank region. In adult summer and winter coats i t was the abdominal hairs which attained greater diameter. The black coloured zone has maximum extent i n the fawn b i r t h coat and decreases consistently t i l l i t reaches adult winter coat. The large guard hairs have greater proportion of t h i s than the intermediate guard h a i r s . Even abdominal hairs have dark t i p s . The yellow coloured zone i s completely missing i n fawn b i r t h coat. It i s present to a very small extent i n the longer hairs of the adult summer coat. I t i s well developed i n fawn winter coat, but reaches i t s maximum extent i n the adult winter coat. The grey-reddish yellow zone constitutes the bulk of the shaft — except i n d i s t a l extremities of limbs. I t i s reddish yellow i n summer and grey i n winter coats. It reaches i t s greatest proportion i n abdominal hairs where i t i s always pale grey i n colour. A white coloured (translucent) zone constituting the basal stalk of the hairs i s c h a r a c t e r i s t i c a l l y longer i n abdominal hairs. It consists only of cortex and hair c u t i c l e . The medulla being absent here. Pigmentation of any kind i s lacking i n t h i s zone. 14-7 o I i i i i i i i i i i i i 0 10 20 30 4 0 50 6 0 LENGTH , MM FIG. 50 REGRESSION LINES COMPARING LENGTH AND DIAMETER RELATIONSHIP IN FAWN SPOTTED AREA AGAINST FAWN NON-SPOTTED AREA AND ALSO IN ADULT WINTER COAT 70 6 0 50 I 40 X I-w 3 0 FIG. 51 HAIR LENGTH AND DIAMETER RELATIONSHIP IN FAWN BIRTH COAT IN AREAS OTHER THAN WHITE SPOTS (SCATTERGRAM) 20 I 10 0 10 2 0 3 0 4 0 5 0 6 0 DIAMETER, MICRONS 7 0 8 0 90 100 CD 7 0 | 6 0 50 FIG. 52 HAIR LENGTH AND DIAMETER RELATIONSHIP IN FAWN BIRTH COAT WHITE SPOTTED REGION ( SCATTERGRAM) x I-z LL) 4 0 3 0 2 0 h _ i i _ 10 2 0 3 0 4 0 5 0 6 0 DIAMETER , MICRONS 7 0 8 0 9 0 100 t—1 VO 7 0 , 6 0 5 0 FIG. 53 HAIR LENGTH AND DIAMETER RELATIONSHIP IN ADULT (BACK) WINTER COAT ( SCATTERGRAM) 4 0 3 0 20 10 60 8 0 100 120 140 160 180 DIAMETER .MICRONS 2 0 0 2 2 0 240 260 H o 8 0 70 FIG. 54 HAIR LENGTH AND DIAMETER RELATIONSHIP IN ADULT (BACK) SUMMER COAT ( S C A T T E R G R A M ) 6 0 5 0 z UJ 4 0 3 0 2 0 10 I ' 1 " 1 1 1 — 6 0 8 0 100 120 1 I I I I I I • • I I L 140 160 180 2 0 0 220 2 4 0 2 6 D IAMETER , MICRONS 152 Chapter VII EFFECT OF ADVERSE NUTRITION AND VARIATION OF HABITAT ON CERVID PELAGE  INTRODUCTION Black t a i l deer are often short of food i n winter, and where populations are high many animals d i e . The adverse n u t r i -t i o n a f f e c t s the general biology of the animal i s a truism. However there i s no information upon the influence of impaired n u t r i t i o n upon the p i l a r y system and whether or not any imposed changes i n the pelage may contribute to the winter mortality of deer l i v i n g under adverse circumstances. The e f f e c t of n u t r i t i o n on animal pelage has attracted some attention. Flesch (195*0 touches on t h i s . Ryder (1958) has adequately reviewed the n u t r i t i o n a l factors a f f e c t i n g hair growth and takes into account among others the contribution of Fraser (1934), Krishnan (1939), Coop (1954), Van Koetsveld (1954) and Ryder (195*0' Bandy (1965) r e f e r s to condition and behaviour of the black t a i l e d deer as affected by the plane of n u t r i t i o n . C h i e f l y the r o l e of n u t r i t i o n has been studied with respect to i t s e f f e c t on the rate of f i b r e production and upon the char-a c t e r i s t i c s of f i b r e s produced, mechanism of hair loss and the period of f o l l i c l e development. To document the e f f e c t of adverse n u t r i t i o n on the cervid p i l a r y system an experiment was designed and the r e s u l t i n g data were studied. MATERIAL AND METHODS 153 Four male black t a i l deer raised under i d e n t i c a l conditions were selected. These were Ul6, TR, U26 and W"4. They were housed under i d e n t i c a l conditions i n the animal unit of the Department of Zoology at the University of B r i t i s h Columbia. A l l the animals were maintained on U.B.C. r a t i o n 3 6 - 5 7 . (Table 2 2 , 2 3 ) . Addison (1965) has worked out the d i g e s t i b i l i t y of thi s r a t i o n (Table 23) and has determined the c a l o r i f i c value of the r a t i o n per gramme, as 3 » 1 3 6 . Animals U26 and W4 were put on an ad libitum d i e t and served as controls. Ul6 and TR were used as experimental animals and were put on a r e s t r i c t e d d i e t . O r i g i n a l l y t h i s was planned as 60% of that consumed by the control animals, but thi s did not have any early e f f e c t s on the experimental animals, perhaps due to n u t r i t i o n a l reserves i n the animals. The d i e t of the experimental animals was therefore reduced u n t i l the f a t reserves were exhausted and the animals evinced the sluggish behaviour accompanying malnutrition. Details of d a i l y c a l o r i c intake and weight at weekly inter v a l s are given i n Appendix 1 and 2 . The ef f e c t of adverse n u t r i t i o n on black t a i l pelage was studied on a comparative basis between control and experimental animals. TABLE 22 COMPOSITION OF ADULT RATION — U.B.C. 36-57 Addison (1965) Ingredient Amount Corn meal 600 l b s . Ground wheat 250 l b s . bran 275 l b s . Molasses 150 l b s . Beet pulp 200 lbs V i t a grass 200 l b s . Soya bean meal 175 l b s . Herring meal 110 l b s . Bone meal 20 lbs Iodised s a l t 20 l b s . 2000 l b s . 155 TABLE 23 NUTRIENT COMPOSITION OF RATION U.B.C. 36 - 57 Compared with N.R.C. REQUIREMENTS FOR GROWING SHEEP - Addison (l? 6 g ) N.R.C. U.B.C. Nutrient Units Requirements! 36 - 57 Digestible mgm/cal3 36.3 32 p r o t e i n 2 Ca mgm/cal 0.97 1.01 p mgm/cal O.87 I . 6 3 Vitamin A Ia/cal 1 .84 44 Vitamin D , I./cal 0.5 44 1 - Calculated from t o t a l d a i l y requirements f o r a 60 l b . lamb. 2 - Crude protein x 60% 3 - Calories of apparent d i g e s t i b l e energy 4 - Total contribution from a l l r a t i o n ingredient not known but a p a r t i a l t o t a l exceeds the N.R.C. requirement. 156 TABLE 24 DIGESTIBLE ENERGY CONTENT OP THE ADULT RATION Addison (1965) D i g e s t i b l e 3 D i g e s t i b l e ^ _ energy energy TATION Gross energy 1 Digestible % c (Dry) (Air dry) Feed faeces ADULT 4363 4136 42 - 63$ 171 to 2873 1518 to 2543 1 - Gross energy i n ca l o r i e s /mg. 2 - % d i g e s t i b i l i t y 3 - Digestible energy i n calories/mgm of oven dry feed 4 - Digestible energy i n ca l o r i e s per mg of a i r dry feed (10$ moisture) 157 Once the normally growing winter coat reached i t s r e s t i n g stage, an a r t i f i c a l hair cycle was Induced by plucking r e s t i n g hairs from selected body s i t e s on control (W4) and experimental ( U l 6 ) animals. Using the technique of immobilization and skin biopsy sampling described i n e a r l i e r chapters, I took samples e a r l i e r from these s i t e s . Their h i s t o l o g i c a l examination enabled me to attempt a comparative record of hair growth i n well fed and underfed animals. The observations of physical c h a r a c t e r i s t i c s of hair (length diameter, colouration) were made as per techniques de-scribed i n e a r l i e r chapters. Weight measurements were made on "Mettler" balance. The t e x t i l e chemistry section of the National Research Council, kindly made some observations on t e n s i l e strength of hairs grown by well fed and underfed animals. The f i b r e s were conditioned and tested at 70 ± 20°F and 65 - 2% R.H. The machine used was CRE (Instron) tester —1.0 inch/min constant rate of specimen extension, giving a breaking time of roughly 20 - 25 seconds. Machine capacity used = 0 - 1.00 l b . I n i t i a l clamp separations = 2 cms. Root end of f i b r e s placed i n the clamp. OBSERVATIONS a) Normally grown winter pelage on control and experimental animals. As soon as the eff e c t of malnutrition was f e l t the experir-mental animals began chewing o f f large patches of hair on the i r sides.and by mid-winter they had bare patches on flanks and thighs. These animals lacked i n s u l a t i o n on large areas of body i n winter and on p a r t i c u l a r l y cold days appeared v i s i b l y affected as 158 manifest by t h e i r s t i f f gait and the f l u f f e d appearance of the remaining body h a i r s . In contrast the control animals had normal pelage and behaved normally. Towards early spring the bare patches on the body of the experimental animals were covered by newly growing winter hai r s , but before they could a t t a i n any degree of length they were chewed o f f again. This tendency to chew off the coat i n undernourished animals was also noticed by Bandy (1965) . who detected i t i n f a l l and winter. My animals exhibited the tendency throughout the year. I t can impose an added stress on animals l i v i n g under conditions of winter c h i l l and malnutrition. I t should not be assumed, however that t h i s behaviour occurs i n the wild where "roughage" i n the form of plant material, even i f of poor q u a l i t y may substitute for the eating of the animal 1s own h a i r . In the body area where the pelage remained i n t a c t the win-ter coat of control animals d i f f e r e d from that of the experimental animals i n the following respects. The coat of control animals was long and sleek. The experimental animals had shed the large guard hairs and the overcoat consisted mostly of intermediate guard hairs and presented a rough appearance. The hairs i n the experimental animal were shorter and narrower than those of control animals, but appeared s t i f f e r than those i n control animals. This s t i f f n e s s can be attributed to greater amount of c o r t i c a l tissue v i s a v i s medulla i n experimental animals, suggesting that undernourishment a f f e c t s more medullary mass within the h a i r s . Krishnan (1939) has suggested that changes i n hair diameter due to adverse n u t r i t i o n are r e s u l t s from changes i n dimensions of medul-l a Ryder (1956) , Coop (195*0 however f e e l that both cortex and medulla are affected by undernourishment. My study suggests that i n deer medulla has the c r u c i a l r o l e to play i n determining hair diameters and thus corroborates Krlshnan (1939)• F i e l d observation of undernourished deer during severe winters on Vancouver Island (Cowan verbatim) suggested that the hairs of these animals broke o f f close to the body leaving the animal i l l covered. This led to the postulate that malnutrition might be responsible for reducing the physical properties of the hair and rendering i t more vulnerable to normal abrasion. Ryder (1958) has given some study to this i n sheep and states that malnutri-t i o n reduces the breaking strength per unit cross-section and makes the wool f i b r e s thinner. In order to explore t h i s p o s s i b i l i t y arrangements were made with the T e x t i l e Chemistry Section of the D i v i s i o n of Applied Chemistry of the National Research Council of Canada. Mr. A.S. Tweedie and Mr. P. Sturgeon kindly made some t r i a l tests of t e n s i l e strength on i n d i v i d u a l hairs taken from our experimental animals. Other evidences of imposed changes i n hair structure was sought i n length, weight, diameter to length and i n the r e l a t i v e development of the cortex and medulla i n the hairs of the two groups of animals. The r e s u l t s were inconclusive. The large guard hairs gave r e s u l t s i n d i c a t i n g that control hairs are a l i t t l e stronger than experimental ha i r s , thus supporting Ryder (1958) °ut observations on intermediate guard hairs gave reverse r e s u l t s (Tables 25, 2 6 ) . Thus contradictory r e s u l t s were obtained. To obtain mean-in g f u l r e s u l t s very large number of hairs would have to be tested 160 U26 F u l l Diet TABLE 25 BREAKING STRENGTH (lb) Fibres Conditioned and Tested at 70 i 2°F and 65 ± 2% R.H. Large Guard Hairs .Ul6 Reduced Diet 9.188 0.207 0.259 0.249 0.225 0.257 0.249* 0.199 0.227 0.321* 0.246 0.280* 0.281* 0.271 0.263 0.180 0.304 0.274* 0.250 0.243 Av = 0.256 Av = 0.242 Average for 7 f i b r e s ( i . e . excluding f i b r e s = 0.240 which slipped) Av = 0.232 0.180 - 0.263 Range for 10 f i b r e s 0.188 - 0.321 *Fibres slipped i n one clamp before reaching breaking load was released f i b r e reclamped and extended t i l l breaking, load was reached. TABLE 26 Intermediate Guard Hairs U26 F u l l Diet Ul6 Reduced Diet 0.133 0.139 0.153 0.163 0.140 0.136 0.119 0.184 0.129 0.133 0.199 0.209 0.202 0.202 0.218 0.182 0.195 0.208 0.183 0.169 Av = 0.144 l b . Range 0.119 - 0.184 l b . Av = 0.197 l b . Range 0.169 - 0.209 l b . *Observations were also made to evaluate e f f e c t of adverse n u t r i t i o n on f i b r e weight. 161 TABLE 27 Intermediate Guard Hairs U26 10 I guard hairs (Av. weight per f i b r e calculated from t o t a l weight of sample) 0.000457 Fibre length Av - 52 mm (approx) Range - 46-58 mm Fibre 10 Ul6 15 I guard hairs 0.00031:4.1!-Av - 39 mm Range - 36-41 mm Fibre 15 *Thus weight of hairs as well as length i s greater i n well fed animals than i n starved animal. 162 and t h i s was not possible. Hair samples c o l l e c t e d from the rump region of well fed and underfed animals were co l l e c t e d when they were i n th e i r winter coat. Regression analysis was done on the length and diameter data c o l l e c t e d . In the well fed animals the hair length varied from 28.00 mm to 75*00 mm as against 23 mm to 52 mm i n the under-fed. The diameter v a r i a t i o n was 117 microns to 277 microns. In the underfed animals the diameter varied from 92 to 235 microns. Regression analysis however revealed that i n underfed animals though the actual mean diameter was les s there was a r e l a -t i v e increase i n diameter for any given length. It would thus appear that with l i m i t e d nutrients growth i n hair diameter enjoys a higher p r i o r i t y than growth i n length. This i s i n consonance with the b e l i e f that hairs with greater diameter not only provide cover but also better i n s u l a t i o n (as they proportionately possess greater medulla). :, At t h i s stage the p o s s i b i l i t y of v a r i a t i o n i n hair length and diameter i n the black t a i l deer forms, occupying d i f f e r e n t climate areas was also investigated. For t h i s purpose black t a i l pelage samples were obtained from Southern C a l i f o r n i a and Alaska. Hairs from i d e n t i c a l regions were compared with B r i t i s h Columbian forms as regards hair length and diameter. The Southern C a l i f o r -nian form inhabiting warm and dry areas was found to possess hairs which were considerably smaller i n diameter, and shorter. The form i n Alaska (sltkensls) presented the greatest diameter. The hair length was however not appreciably greater than that found i n the B r i t i s h Columbian v a r i e t y . The consistent increase i n hair diameter from Southern C a l i f o r n i a to Alaska again underscores i t s 8 0 T TO ©or so i K ' 4 1 0 } 3 0 — i — i — i — i — i — i — i — i — i — i — \ — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i i i i i i i i i i <~-RG.55 WINTER COAT (RUMP)HAIR LENGTH AND DIAMETER RELATIONSHIP UN CHANGING IH'ABTTAT • • o • • o • • D O 0 o ° o o o o o o o i ( o = S . C A L I F O R N I A FORM ) (a = B R I T I S H COLUMBIA FORM) (m = ALASKAN FORM ) • • i i i i i i_ * * • i i i i 1_ _ l I L_ 2 0 40 60 SO 1100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 DIAMETER, MICRONS H ON N J J 164 importance i n providing adequate i n s u l a t i o n to the animal, b) The a r t i f i c i a l l y induced hair cycles. The a r t i f i c i a l hair cycle was started by plucking r e s t i n g hairs from the thigh region of the control (w4) and experimental ( U l 6 ) animals. Most of the guard hairs were easy to pluck. The woolly hairs were d i f f i c u l t to pluck — i n the sense that most of them broke at the surface, leaving part embedded i n the f o l l i c l e . The new hair cycle study was thus confined to guard h a i r s . Fortnightly observations on the plucked s i t e s on control and experimental animals did reveal that n u t r i t i o n had an e f f e c t on emergence of new hairs on plucked s i t e s . Although hairs were plucked on control and experimental animals on the same day i . e . 1st November 1966, the time at which the new hairs emerged on the surface were d i f f e r e n t . In the control animal they emerged i n 60 days while i n experimental animal they emerged i n 90 days. The r e s t i n g stages were reached i n W"4 by mid-March and that i n U l 6 by mid-April, i n the plucked s i t e s . Thus the duration of the growth period ( a r t i f i c i a l l y induced) i s similar to that i n normal hair cycle and d i d not d i f f e r between the experimental control animals. Lowenthal and Montagna (1955) found that i n mice "when the hairs are plucked at the time when the animals are placed on reduced d i e t the f o l l i c l e s remain quiescent f o r as long as two months but they become active on the very day the animals are given ad lib i t u m food". My experimental animals were placed on reduced diet for some time before the a r t i f i c i a l hair cycle was a c t u a l l y started and during the experiment at no time were they given ad libitum A r t i f i c i a l l y induced hair cycle FIGURE 5 6 . 1 Plucked f o l l i c l e s regrowing i n underfed animal ( U l 6 ) f i r s t week. Notice the rounded dermal p a p i l l a , enveloping f o l l i c l e base and cord of undifferentiated c e l l s above i t . Longitudinal section. H. & E. FIGURE 5 6 . 2 Plucked f o l l i c l e s regrowing i n well fed animal (W4) f i r s t week. Note the appearance of plucked f o l l i c l e . Longitudinal section. H. & E. FIGURE 57 Hairs emerging a f t e r four weeks i n well fed animal (W4). Transverse section. H. & E. FIGURE 58 Hairs a c t i v e l y growing two months a f t e r plucking i n underfed animal ( U l 6 ) . Longitudinal section. H. & E. For explanation of abbreviations used please see Appendix IV, Page 2 1 4 . 166 167 d i e t . At one stage (mid-Dec. 1966) owing to considerably weakened condition of U l 6 , his d i e t was increased. It i s conceivable that t h i s increase i n d i e t may have triggered the hair growth cycle e a r l i e r than i t would have otherwise started. In both the animals hairs grew considerably longer i n the v i c i n i t y of the biopsy s i t e s than elsewhere on the plucked area. Ebling (1964) f i r s t reported that hairs a t t a i n greater lengths at the s i t e of wounds and sutures during his work on hair growth. This can now be confirmed also for deer. The hairs growing In the plucked areas were of winter type but did not exhibit the metallic grey colouration i n early stages of growth so c h a r a c t e r i s t i c of the early stages of a normally grown winter coat, instead they were light-brown i n colour. Here too the hairs i n experimental animals were of smaller length and diameter than those of the control animals. The difference i n colouration of the early phases of a r t i f i c i a l l y induced hairs (growing i n Nov. - Dec.) and normally growing winter hairs (August to Sept.) could be at t r i b u t e d to subtle biochemical changes within the hair f o l l i c l e as i t prepares i t s e l f for the production of normal summer h a i r s . c) H i s t o l o g i c a l changes during the a r t i f i c i a l hair cycle When the experiment was started on November 1, 1966, the winter coat had f i n i s h e d growing and a l l the primary f o l l i c l e s were i n telogen. In the black t a i l e d deer t h i s stage i s similar to that found i n the mouflon, Ryder (1966). The f o l l i c l e ceases produc-t i o n of medulla and the basal hair part i s consequently devoid of i t . The r e s t i n g hair f o l l i c l e i s pulled towards the skin surface FIGURE 59 Well fed animal In winter coat. FIGURE 60 Underfed animal i n winter coat. Notice coat chewed o f f on sides r e s u l t i n g i n bare patches and rough appearance of the coat. FIGURE 61 Hairs growing faster i n the v i c i n i t y of skin biopsy areas. Notice the sampling s i t e s . FIG 61 FIG.62 WINTER COAT GUARD HAIR (BACK) LENGTH AND DIAMETER RELATIONSHIP IN W E L L FED A N I M A L ( S C A T T E R G R A M ) 2 0 h I 0 ' " • 1 1 " 1 1 1 1 1 i i i • • i i i I 8 0 100 120 140 160 180 2 0 0 2 2 0 240 260 2 8 0 D I A M E T E R , MICRONS 80 7 0 60 5 0 FIG.63 WINTER COAT GUARD HAIR (BACK) LENGTH AND DIAMETER RELATIONSHIP IN UNDERFED ANIMAL (SCATTERGRAM) o z 4 0 30 20 -10 80 100 1 2 0 140 160 180 200 220 240 260 2 8 0 DIAMETER , MICRONS 1 0 0 -0 10 20 30 4 0 LENGTH , MM FIG.64 REGRESSION LINES COMPARING LENGTH AND DIAMETER RELATIONSHIP B E T W E E N WELL FED AND UNDERFED WINTER COAT GUARD HAIR SAMPLES 173 and the hair base l i e s near the v i c i n i t y of the arrector p i l i i muscle attachment. The hair base has a brush end and i s enclosed i n an epidermal capsule. The f o l l i c l e base i s connected to the hair base by a cord of undifferentiated c e l l s . The bulb of the hair f o l l i c l e i s greatly reduced i n s i z e . The dermal p a p i l l a i s rounded and h a l f enclosed by the bulb. In r e l a t i o n to the bulb i t i s proportionately greater than that found i n a c t i v e l y growing f o l l i c l e s . The c e l l s at the base of the f o l l i c l e covering the dermal p a p i l l a are much larger and prominently nucleated. Some melanocytes are also present within t h i s region. The f o l l i c l e has l o s t i t s inner root sheath and the epidermal capsule i s of external root sheath o r i g i n . The f o l l i c l e as well as dermal p a p i l l a are enclosed by a layer of c e l l s of connective t i s s u e . This layer i s separated from external root sheath by a glassy membrane v i s i b l e at places. Generally the parts of the res t i n g f o l l i c l e s l y i n g below the attachment of arrector p i l i i muscle are straight but often get bent s l i g h t l y to one side. When the hairs were plucked out at t h i s stage the remaining external root sheath was pulled out and mostly destroyed. The connective tissue elements as well as the glassy membrane are present i n the f o l l i c u l a r region. The process of regeneration and repair s t a r t s immediately and within a week the bulbs of the f o l l i c l e s have descended to lower depths. The cord of the undif-ferentiated c e l l s above the bulb has increased i n length and i s the cause of t h i s elongation. The dermal p a p i l l a has.been rounded and i s mostly enclosed by the f o l l i c l e bulb. The melanocytes are no longer r e s t r i c t e d to layers immediately above the dermal p a p i l l a but none occur along the length of the growing f o l l i c l e . 174 The newly developing f o l l i c l e i s often twisted along i t s length. In a 4th week sample the f o l l i c l e bulb has become enlarged and the dermal c e l l elements are rounded. The dermal p a p i l l a i s enclosed by the f o l l i c l e bulb, which i n turn has reached the l e v e l of the sweat gland ( d i s t a l end). The same state continues i n the 5th week also. Blood vessels are present i n the p a p i l l a and a membrane separates the f o l l i c l e c e l l s from the p a p i l l a c e l l s . By the 6th week the large guard hairs have emerged on the surface. These f o l l i c l e s grow at a faster rate than the intermediate guard hair f o l l i c l e s . In the well fed animals the regeneration process sta r t s immediately and the the 4th week large guard hairs are emerging on the surface. In the underfed animals most of the f o l l i c l e s experience arrested growth afte r reaching the stage when they produce a long cord of undifferentiated c e l l s with f o l l i c l e bulb enclosing three fourths of dermal p a p i l l a . Summary Underfed animals have shorter and more slender hairs than well fed controls; the hairs also weigh l e s s . There i s non-consis-tent demonstrable difference i n t e n s i l e strength of hairs from control and experimental animals. Also undernourishment seemed to have no e f f e c t on the percentage of woolly undercoat. Woolly under hairs are d i f f i c u l t to pluck, since during the attempted plucking they get broken off at the skin surface. The hair cycle induced a r t i f i c i a l l y by plucking hairs i s mainly concerned with guard h a i r s . The regeneration of plucked f o l l i c l e s s t a r t s immediately, but i n the underfed animal appears to have been arrested for a longer time i n a t r a n s i t i o n a l stage. In 175 control animal the f o l l i c l e regeneration and hair development i s fast e r , and that of the large guard hairs i s fas t e r than that of the intermediate guard hair f o l l i c l e . In control animal the large guard hairs have begun to emerge on the surface i n the 4 th week and by the 6 th week most of the other guard hairs have emerged. In experimental animals the large guard hairs emerge by the 6th week and the rest by the 8th week. Experimental animals were observed to chew off hairs on the body; t h i s gave r i s e to bare patches on the flanks. 176 Chapter VIII G-ENERAL DISCUSSION The families cervidae and bovidae are the two major groups i n the wide and diverse assemblage of the exi s t i n g ungulates (Simpson 19^5). However knowledge of the ungulate p i l a r y system has been v i r t u a l l y confined to the Bovid genera Bos, Ovls, and Capra. It i s therefore of p a r t i c u l a r interest to compare the information on these with the d e t a i l s from a cervid form i . e . Odocolleus hemlonus columbianus, and to see whether any s i g n i f i -cant evolutionary or adaptive trends emerge. F o l l i c l e development and Anatomy Embryologically the cervid f o l l i c l e development f i t s into the general mammalian pattern; and goes through the same develop-mental stages. Unfortunately no known-aged series of deer foetuses was avai l a b l e , and to develop such a series would have involved a long-range special breeding programme. Consequently no comparisons on the timing of stages of f o l l i c l e development or emergence of hairs on the body, have been made with other ungulates. However these have been related to designated size stages i n embryogeny. As the regards the development and the r e l a t i v e size of the f o l l i -c l e accessories the deer resembles domestic sheep. The secretory portion of the deer sweat gland , however, i s quite sinuous. This i s not so i n sheep or c a t t l e , and i n the l i g h t of present knowledge appears to be a unique cervid feature. Sokolov (1963) states that i n wild a r t i o d a c t y l of U.S.S.R. some sweat glands disappear completely during the winter and the secretory portion 177 of the others i s reduced. No such seasonal changes i n these glands have been encoun-tered i n Odocoileus hemionus columbianus. and the sweat gland features remain constant. In the genera studied by Sokolov i t would, however, be of int e r e s t to document i n d e t a i l the redevelopment of a sweat gland that had regressed during the previous winter. I t i s not stated i f the sweat gland referred above are of eccrine or apocrine type. In Odocolleus they are a l l apocrine type. In Odocolleus, as i n c a t t l e , sheep and goats, each f o l l i c l e i s associated with no more than one sebaceous gland and thi s may be completely missing i n some of the smallest f o l l i c l e s . In larger f o l l i c l e s the sebaceous gland i s often bilobed; but no d i s t i n c t i v e a c i n i i have been observed i n these lobes. Sokolov (1963) states that the number of sebaceous glands at each hair varies from one to three. This i s not so i n Odocolleus, but l i k e Alces the sebaceous glands i n Odocoileus do appear to be more developed and enlarged i n summer. This may Indicate a more active role during t h i s season. The hair f o l l i c l e s of Odocolleus. sheep, and goats have been c l a s s i f i e d into primaries and secondaries. The primaries can be further divided into central primaries and l a t e r a l primaries. A l l the primaries are associated with sweat gland, sebaceous gland and A. p i l i i muscle. The secondaries have i n turn been divided into f i r s t formed and l a t e r formed. The f i r s t formed secondaries are larger, as i n goats, mouflon, and some domestic sheep breeds. The Odocolleus d i f f e r s from these i n the possession of a sweat gland, and an A. p i l i i muscle i n addition to the sebaceous gland. 178 This has not been recorded before. Such an occurrence, however, r a i s e s doubts about the v a l i d i t y of the standard c h a r a c t e r i s t i c s d i s t i n g u i s h i n g a primary from a secondary f o l l i c l e . I t ra i s e s the question whether there i s at a l l : any fundamental primary and secondary f o l l i c l e types. It i s possible that they are d i f f e r e n t stages of continuum, r e f l e c t i n g , i n t h e i r size and morphology, the gradual depletion of the f o l l i c l e - f o r m i n g substance. In case of c a t t l e each of the hair f o l l i c l e s possesses a sweat gland, seba-ceous gland and A. p i l i i muscle; but the f o l l i c l e * s develop at d i f f e r e n t sequential ages. Consequently they have been c a l l e d f i r s t formed, l a t e r formed and l a s t formed, By accepted d e f i n i -t i o n however they a l l are homologous to the primary f o l l i c l e s , o f sheep, goats and deer. Anatomically a l l the basic c e l l layers constituting the f o l l i c l e s are common to the ungulates. The following features are noteworthy for Odocoileus. The external root sheath i s well developed and uniform around the f o l l i c l e as opposed to sheep where i t i s better developed on the ental side. Unlike sheep i n deer the glassy membrane i s also often c l e a r l y v i s i b l e i n the basal bulb region, where the external root sheath i s considerably reduced. In Odocolleus an addit i o n a l glassy membrane occurs between the external and i n t e r n a l root sheath. This has not been reported i n sheep, goat or c a t t l e . It would be in t e r e s t i n g to know how widespread t h i s c h a r a c t e r i s t i c i s among the cervidae and i t s functional u t i l i t y . Henle's layer of inner root sheath i s large and stains more heavily with Haematoxylin and Eosin than the adjoining Huxley's layer l y i n g on i t s inner side. Both layers are single c e l l e d but i n the l a t t e r the c e l l s are smaller. In 1 7 9 deer Henle's layer i s of uniform thickness unlike that i n sheep where i t i s thicker on the ental side. The developing primary f o l l i c l e s i n Odocolleus are char-acterized by the presence of an ental swelling. No evidence was observed to Indicate that the A. p i l i i muscle had anything to do with i t . My observations support Lyne and Heideman's ( 1 9 5 9 ) contention that there i s no cause-and-effect r e l a t i o n s h i p between the ental swelling and the A. p i l i i muscle. There was however a consistent r e l a t i o n s h i p between t h i s muscle and the sweat gland — they always occurred together. As i n c a t t l e the t r i o f o l l i c l e grouping i s c l e a r l y apparent i n the developmental stages but gets somewhat obscured subsequent-l y owing to growth of the body and resultant stretching of the skin. In deer the f i r s t formed secondary f o l l i c l e s are larger than i n the goat and a f o l l i c l e grouping of f i v e (three primaries and two f i r s t formed secondaries) becomes prominent. This has also been observed i n goat, mouflon, and some breeds of domestic sheep, but not i n c a t t l e . In sheep the secondary f o l l i c l e group i s located e n t i r e l y between the primaries, but i n deer and goats i t i s only wedged between the primaries. In goats the f i r s t formed secondary f o l l i c l e forms the apex of t h i s wedge but t h i s i s not always the case i n deer. In the course of the hair f o l l i c l e development i n Odocolleus some of the central primaries follow a d i f f e r e n t path. They are only a stage or two ahead i n development i n respect of other central primary f o l l i c l e s but grow at a much faster rate and a t t a i n large s i z e . This i s p a r t i c u l a r l y obvious i n a 2 6 9 and 2 8 7 mm foetus. Occasionally the neck region of these f o l l i c l e appear 180 bulbous, but no d e f i n i t e sinus has been detected there. These f o l l i c l e s are very similar to the t y l o t r l c h s discussed by S t r a i l e (1961) and are morphological types l y i n g i n between the v i b r i s s a f o l l i c l e and the normal hair f o l l i c l e . The discrepancy i n f o l l i -c l e size i s noticeable prenatally, but subsequently these f o l l i c l e s cannot be distinguished c l e a r l y from other adjoining primary f o l l i c l e s . These speci a l i z e d f o l l i c l e s produce a long guard hair — obvious on the skin surface of 287 mm foetus. These have been c a l l e d large guard h a i r s . In adult pelage they can be i d e n t i f i e d by t h e i r length — which i s 1 V 2 times longer than other guard hairs; and occur scattered about 2 . 5 mm apart. Their stimulation produces a twitching response i n animals — thus giving support to the suspected sensory nature of the f o l l i c l e s i n which they a r i s e . Flerov ( i960) r e f e r s to large guard hairs occurring i n cervid forms l i k e Dama, Capreolus, but makes no reference to t h e i r development or l i k e l y function. In c a t t l e about six percent of hair f o l l i c l e s have been reported to be of giant size at maturity and not during development. There are no data on the types or function of hairs produced by these f o l l i c l e s . In goat and sheep, no reference to such f o l l i c l e s or hairs was noticed. My observa-t i o n thus probably are the f i r s t d e f i n i t i v e account of the devel-opment and l i k e l y function of the large guard hairs i n ungulates. They appear to be c h a r a c t e r i s t i c of forest-inhabiting cervids but not of the plains and uplands dwelling ovlnae and caprinae. The primaries and f i r s t formed secondaries i n deer form medullated h a i r s . Those a r i s i n g i n primaries constitute the guard h a i r s . The f i r s t formed secondaries give r i s e to medullated hairs of t r a n s i t i o n a l type present only i n the f i r s t fawn pelage. The 181 other secondaries give r i s e to non medullated woolly under h a i r s . Some of the natal primary f o l l i c l e s instead of producing normal guard hairs give r i s e i n the fawn b i r t h coat, to white tipped hairs c h a r a c t e r i s t i c of the white spots. These same f o l l i c l e s i n the subsequent hair cycles produce normal guard h a i r s . Thus the primary f o l l i c l e s are capable of producing d i f f e r e n t hair types during the animal's l i f e span. This has been shown to occur i n merino where f o l l i c l e s f i r s t producing medullated hai r s , i n l a t e r hair cycles produce non medullated hai r s , Wildman (1937)' The dermal papil l a e vary with the type of hair being pro-duced, they are spatulate i n heavily medullated hairs and have a pointed apex i n hairs having small medulla or no medulla at a l l . In the f o l l i c l e s producing white tipped hair the dermal p a p i l l a however has a pointed apex. Also i n the white tipped hairs the cortex i s r e l a t i v e l y well developed v i s a v i s the medulla and the medulla i t s e l f lacks the i n t r a c e l l u l a r c a v i t i e s present i n other deer guard h a i r s . This i s a unique Odocoileus feature and not recorded f o r other ungulates. The duration of hair f o l l i c l e development i s also variable with f o l l i c l e types. Lyne (1965) states that i t i s inversely proportional to the mature size of the hair f o l l i c l e . This i s true f o r deer guard hairs where the smaller guard hairs come to r e s t e a r l i e r than the large guard h a i r s . But the deer secondary f o l l i c l e s pose a problem. The f i r s t formed secondaries behave l i k e smaller primaries, and precede them i n coming to r e s t . The l a t e r formed secondaries, which are smaller i n size follow a cycle of t h e i r own and have no r e l a t i o n s h i p with the primary and f i r s t formed secondary. A l l primary f o l l i c l e s and f i r s t formed second-a r i e s are well formed at b i r t h and are functional, the l a t e r 182 formed secondaries continue to form post n a t a l l y and become functional only i n the fawn winter coat. This does not however increase the f o l l i c u l a r density i n the postnatal stages. As increase i n body size and r e s u l t i n g d i l u t i o n of f o l l i c l e popula-t i o n more than compensates for the new secondaries being formed. Ryder (1966) states that i n goats the f i r s t formed"hairs reached r e s t i n g stage f i r s t . This i s of great inte r e s t as i t contradicts the normal trend of events i n ungulates. Also i n deer the rate of f o l l i c l e growth, as opposed to the rate of f o l l i c l e development, i s variable i n d i f f e r e n t f o l l i c l e s . Thus the large guard hair f o l l i c l e s though only a stage or two ahead of t h e i r contemporaries i n development are none the le s s much longer (at l e a s t i n f o e t a l material) and t h i s can only be brought about by a faster rate of c e l l d i v i s i o n . The factors responsible for t h i s d i f f e r i n g growth rate are not well known. The various hair f o l l i c l e s are i n close proximity of each other and the governing factors must operate i n some subtle way. Paired f o l l i c l e s present i n c a t t l e have also been detected i n the deer. These generally are confined to l a t e r formed secondaries, one of which i s of larger s i z e . These f o l l i c l e s a r i s e independently very near each other but the hairs produced by them emerge through a common aperature. This has not been record-ed for sheep or goats. Branching f o l l i c l e s involving three to four secondaries of successively smaller size a r i s i n g from a l a t e r formed secondary have also been recorded i n deer. These are absent i n c a t t l e but present i n sheep and goats. Branching of the secondaries are p a r t i c u l a r l y well developed i n merino sheep where upto six or 1 8 3 seven wool f i b r e s may emerge from a f o l l i c u l a r aperture. However i n as much as t h i s condition has not been reported for wild sheep, i t must be regarded as a mutation selected during generations of husbandry. The normal ungulate pattern i s for not more than two to three h a i r s , from simple branched f o l l i c l e s to emerge from a single aperture. In addition the merino skin, unlike any Jbhat -of other ungulate, i s greatly folded, which increase the number of f o l l i c l e s on the body. Epidermis and dermis During the course of f o l l i c l e development the epidermis and the dermis undergo c e r t a i n changes. The collagen f i b r e s i n the r e t i c u l a r layers of the dermis increase i n size and with maturity some may even be formed i n the p a p i l l a r y layer. In the epidermis the stratum spinosum increases i n size as f o l l i c l e s are formed but at maturity i s hardly distinguishable as a discrete lamina as there i s a continuum of c e l l s from the basal layer to the peeling stratum corneum. Sokolov ( 1 9 6 3 ) states that the dermis, and in p a r t i c u l a r i t ' s p a p i l l a r y layer, i s thicker i n summer than i n winter. This i s also true of the stratum spinosum. Stratum corneum however behaves i n reverse fashion. This has not been d e f i n i t i v e l y established i n Odocolleus. Ling ( 1 9 6 5 ) states that most of the animals undergo a moult prenatally or immediately a f t e r b i r t h . There was never any i n d i c a t i o n of t h i s i n Odocolleus. Of course during embryonic development the 'periderm' i s sloughed and replaced by the stratum corneum, but hairs are not yet present at t h i s time. 184 Hair types and morphology The deer i n course of i t s l i f e cycle bears four character-is t i c , " . coats . When the black t a i l fawns are born i n summer they bear the b i r t h coat. This coat has summer coat c h a r a c t e r i s t i c s . The important point of difference being that here there i s a d i s t i n c t i v e undercoat. In adult deer i t i s only r e s t r i c t e d to the winter coat. Also the hairs constituting the b i r t h coat undercoat are mostly of t r a n s i t i o n a l type (and not true woolly) and have fragmental medulla. They a r i s e i n the smaller of the primary f o l l i c l e s and the f i r s t formed secondaries. The l a t e r formed secondaries which give r i s e to the non medullated woolly under hair of the fawn and adult winter coat are s t i l l forming and not fun c t i o n a l . As many of the b i r t h coat undercoat hairs a r i s e i n primary hair f o l l i c l e s and as i t i s present i n a summer type of pelage i t may be considered i n part homologous to c a t t l e undercoat. In c a t t l e a l l the hair f o l l i c l e s are struc-t u r a l l y comparable to the primary f o l l i c l e s of deer, sheep and goat, and the undercoat i s present generally i n both summer and winter pelages. The points of difference being that i n c a t t l e the undercoat hairs a r i s e i n f o l l i c l e s homologous to deer primary f o l l i c l e s and are a l l non medullated. They are not woolly. The presence of an undercoat i n an e s s e n t i a l l y summer type of coat, as occurring i n the fawn b i r t h coat may be d i r e c t l y related to the need of the fawn for better i n s u l a t i o n i n i t s early stages. An adult deer i n the summer appears to have no such i n s u l a t i o n need, and the undercoat i s conspicuously lacking. The c h a r a c t e r i s t i c i f l u f f y appearance of the newly born fawn can be attr i b u t e d to greater f o l l i c u l a r density which i s 185 subsequently reduced: by expansion of the skin area without equivalent increase i n f o l l i c l e elaboration. The greater f o l l i -c l e density r e s u l t i n g i n greater hair concentration also undoubt-edly contributes to better i n s u l a t i o n i n early stages of fawns l i f e . This may also occur i n the newly born of other ungulates but i s ;-str.l.kingly noticeable i n the black t a i l . At f i r s t glance the white-tipped hairs of the fawn b i r t h coat appeared similar to heterotypes (hairs with weak basal end but well formed d i s t a l end) formed i n sheep. Morphometric (length and diameter) study of hair samples revealed no e s s e n t i a l morpho-metric difference between these hairs and those occurring near them. The differences are only of colouration whose basis l i e s i n the biochemistry of the hair f o l l i c l e s . The difference of the cortex and the medulla have been referred to e a r l i e r . The hair types present on the body of the black t a i l resem-ble those present on the body of the goat; i n respect of t h e i r general form. The beard type of hairs i n deer i s r e s t r i c t e d to the t a i l and inguinum. The large and the intermediate guard hairs of deer are the kemp type and comparable to kemps of the goat. The smallest of deer intermediate guard h a i r s , and those c o n s t i t -uting the bulk of the under coat i n fawn b i r t h coat, and are i n form similar to intermediate type hairs i n the goat. The hairs a r i s i n g i n f i r s t formed secondaries are also of intermediate type. The woolly under hairs constituting the undercoat of the deer are comparable to the woolly undercoat hairs of the goat. This i s d i f f e r e n t from the hair types formed i n that i n sheap, the under-coat overtops the coarse outer coat h a i r s . 186 The general c h a r a c t e r i s t i c s of pelage of non-woolly animal remains constant, although there may be some v a r i a t i o n i n d e t a i l with changing seasons. Fibres may vary greatly i n length and diameter but a l l grade into one another from one extreme to the other. "Usually the coarser f i b r e s extend well beyond the others and approximate to a loose d e f i n i t i v e coat while the f i n e r f i b r e s are c l o s e l y disposed and suggest wo:o£ly/ undercoat". Thus essen-t i a l l y a l l the f i b r e s are of one type. Cattle f a l l Into t h i s category. In mouflon the undercoat reached the same length as the overcoat, whereas i n the case of goat the under wool was shorter than that of mouflon and thus l i k e that i n deer Ryder ( 1 9 6 6 ) . In deer no awns have been observed. It i s also int e r e s t i n g to r e c o l l e c t that Friend & Hesselton (1966) observed i n an Odocoileus vlrglnianus patches on the body where the woolly under hairs had overtopped guard hairs which were not v i s i b l e externally. This condition of exposed wool has been reported as a rare anomaly. No doubt i t i s genet i c a l l y regulated and occurs as a mutant state. If one were to trace the development of woolly coat i n ungulates studies, c a t t l e would represent the primitive non-woolly type; deer and goat represent the primitive wooly type; the mouflon has a greater development of wool; next come domestic sheep breeds, terminating i n the merino, which represents the woolly coat at i t s hightest development so f a r . The c u t i c u l a r scale c h a r a c t e r i s t i c s of the hair types are of i n t e r e s t within a group such as the ungulates; these have been found to depend on the physical dimensions of the hair and not on i t ' s morphological type (Mahal et a l 1 9 5 1 ) . Appleyard ( i 9 6 0 ) 187 r e f e r s to scale patterns on hairs from genus Cervus and states that coarse hairs have at t h e i r base an " i r r e g u l a r p e t a l " scale pattern, while at mid-way and at the t i p i t i s "ir r e g u l a r waved mosaic" with 'smooth' margins and in t e r marginal distance •close'. In the case of black t a i l only some of the very thick guard hairs bear " i r r e g u l a r p e t a l " scale pattern on the base — a l l the others bear "irregular mosaic" to " i r r e g u l a r waved mosaic" Appleyard's ( i 9 6 0 ) statement that a l l fi n e hairs i n Cervus bear fragmental medulla i s of in t e r e s t , as i n the case of black t a i l the f i n e woolly under hairs are non-medullated. They also bear a scale pattern which resembles a v a r i a t i o n of the. coronal type as referre d to by Mahal et a l ( 1 9 5 1) rather than the i r r e g u l a r waved mosaic pattern as suggested by Appleyard ( i 9 6 0 ) . If one i s to take into account the black t a i l hair scale morphology i n compar-ison with c a t t l e , sheep and goat, then black t a i l can be said to resemble sheep. "Rippled crenate" scale margins present i n regions of c a t t l e and goat haifis were at no time observed on black t a i l h a i r s . The narrowing of the l a t t i c e d medulla i n the base of the guard hairs i n deer i s more abrupt than that i n the sheep. Also branched hair f i b r e s of the type referred by Ryder ( i 9 6 0 , 1 9 6 6 ) as occurring i n the mouflon and the goat have not been observed i n Odocoileus. Adult Odocoileus have two d i s t i n c t seasonal pelages and these replace each other a l t e r n a t e l y according to the season. These coats d i f f e r from each other i n respect of hair dimensions and colouration. The summer coat hairs are longer, more slender and i n general the pelage presents a reddish-yellow appearance. The 188 winter coat hairs on the other hand presents an o v e r a l l greyish appearance; have larger diameter, and more crimped nature of the hair shaft. The summer coat hairs (intermediate guard hairs) presented no d i s t i n c t i v e length to diameter r e l a t i o n s h i p pattern whereas hair growing from the same f o l l i c l e s i n winter have had a d i s t i n c t i v e c o r r e l a t i o n between length and diameter i . e . increasing length. The winter coat i s also characterized by possession of woolly undercoat — a r i s i n g i n secondary f o l l i c l e s . This i s absent i n the summer coat. These changes i n hair colouration and morphology are of pa r t i c u l a r significance because the same f o l l i c l e s produce these two types of h a i r s . The changing a c t i v i t y pattern of the melano-cytes, and the variations i n biochemical reactions involved prod-ucing melanin, pheomelanin etc., would be of p a r t i c u l a r i n t e r e s t to study. The f o l l i c l e s producing 'white-tipped' hairs i n fawn are also of intere s t as i t i s obvious that during the formation of the white t i p the melanocytes are behaving very d i f f e r e n t l y . Billingham and S i l v e r s ( i 9 6 0 ) suggest that white colouring or "spotting" may be due to a genetic ba r r i e r preventing melanocytes from reaching th e i r end organ from the neural crest or at l e a s t f a i l i n g to d i f f e r e n t i a t e . The f o l l i c l e s producing white-tipped hairs however often show a brownish pigmentation. Perhaps t h i s i s because the white t i p has already been formed, and the res t of the hair body which i s pigmented i s i n the process of formation. Such sharp changes of colouration have not been referred to i n goat, mouflon, domestic sheep, or i n c a t t l e . The length and diameter v a r i a t i o n i n summer hairs produced by the same f o l l i c l e i s also of great i n t e r e s t , and r e f l e c t s 189 functional p l a s t i c i t y on the part of the hair f o l l i c l e s . The environmental conditions may also have a bearing on these normally occurring changes. The hair length can,be varied either by increased rate of growth, or longer period of growth. In deer the former appears l i k e l y as no noticeable change i n the duration of hair growth was detected i n the present study. Use of auto-radiographic techniques may help to elucidate t h i s issue. The major factor responsible for the changes i n hair diameter i s the medulla, but the processes governing i t s formation are not c l e a r . This must vary i n d i f f e r e n t body regions of the same coat too, for i n adults the abdominal hairs have a much larger development of the medulla. Adaptive value The major function performed by Odocolleus pelage i s i n adapting the animal to i t s environment and a c t i v i t i e s within the pelage l i k e the hair growth cycles and the timing of moult are oriented towards meeting the above mentioned objective. The deer winter coat has features adapted to increase the i n s u l a t i o n capacity. These are, productions of heavily medullated hai r s , and the presence of a well developed woolly undercoat. The crinky nature of the intermediate guard hairs i s h e l p f u l for proper accommodation of the woolly undercoat. The greater v a r i a t i o n i n the length of in d i v i d u a l winter coat guard hairs, enables them to be arranged compactly and thus provide better i n s u l a t i o n . The significance of the medulla i n deer i n s u l a t i o n i s further attested by the fac t that the Southern C a l i f o r n i a n forms l i v i n g i n dry a r i d conditions have i n the i r winter coat hairs much less proportion 190 of medulla, (resulting i n smaller hair diameter) than noticed i n the i d e n t i c a l region of the Alaskan forms l i v i n g under very cold winter conditions. The absence of woolly undercoat i n summer and the longer hairs makes summer coat often, more amenable to a i r c i r c u l a t i o n , and thus well suited for warm summer conditions. As a further adaptation to thermoregulation, the pinnae of deer i n height of summer appears naked and sharing a sparse "down" of small h a i r s . I did not determine whether or not there was a seasonal reduction i n the number of f o l l i c l e s producing hairs, however t h i s seems probable. The blood supply here i s profuse and i t i s tempting to suggest that t h i s may have some thermoregu-l a t o r y function i n the deer. Production of a woolly undercoat i s not the only way i n which cervids have adapted to winter conditions. The sub genus Przewalskium a cervine form inhabiting cold Tibetan highlands has i n i t s winter coat no woolly undercoat (Flerov i 9 6 0 ) . Instead i t ' s winter coat consists of thick heavily medullated h a i r s . This supports the contention that i n deer hair medulla i s of great importance i n securing adequate i n s u l a t i o n . I t would be of great inter e s t to examine t h i s coat h i s t o l o g i c a l l y as well as to compare in s u l a t i o n capacity of thi s type of coat with that where a woolly undercoat i s also present. Woolly undercoat i s present i n goats and mouflon and i s dominant i n the domestic sheep, and provides e f f e c t i v e i n s u l a t i o n i n cold conditions. In c a t t l e however the s i t u a t i o n i s d i f f e r e n t . Dowling (1959) has concluded that here the summer hairs are shorter than winter hairs and possess greater medullation and hair diameter. The winter coat f i b r e s are on the other hand long and 191 non-medullated. Dowling further contends that -thicker shorter medullated f i b r e s which are s t i f f e r enhance a i r movement at the skin surface. This would provide a greater opportunity for evaporation of moisture. Further the more medullated the f i b r e the more e f f e c t i v e would be the r e f l e c t i o n of the i n f r a red wave lengths of solar r a d i a t i o n . He also found on experimentation that animals with medullated coat were more heat-tolerant than those having hairs without or with small medulla. In Odocolleus the mechanism i s obviously d i f f e r e n t and heavy medullation f a c i l -i t a t e s better i n s u l a t i o n . Apparently i n c a t t l e the winter insu-l a t i o n i s affected only by having a longer coat, which may provide better body coverage. Like deer i n c a t t l e too there i s greater v a r i a t i o n i n hair length of winter coat h a i r s . Moult In deer the summer and winter coats are assumed by the animal through a process of moulting, just before the onset of the summer and winter seasons respectively. Thus the deer overcoat moults twice namely i n spring, and la t e summer to early autumn, and the woolly undercoat moults only once a year namely i n spring. The primary and l a t e r formed secondary f o l l i c l e s thus have d i f f e r -ent cycles. The goat has comparatively a very primitive cycle. Here both primary and secondary f o l l i c l e s undergo a similar cycle i.e of a c t i v i t y i n summer and i n a c t i v i t y i n winter. In summer the goat lacks woolly undercoat. In mouflon both the primary and secondary f o l l i c l e s are shed i n spring, and the pelage i s devoid of woolly undercoat i n summer. Some primaries are also shed again i n autumn, but there i s no moult as such. This i s homologous to 192 deer autumn moult. This i s also true of primitive domestic sheep and to a lesser extent i n the more highly evolved domestic sheep. In c a t t l e , although some hairs are constantly being shed a l l the year around (very much unlike deer), two d i s t i n c t shedding periods have been observed namely i n spring and the autumn. The overcoat and undercoat are shed and replaced twice a year. In Odocoileus spring and autumn moults have d i f f e r e n t d i r e c t i o n s . The autumn moult i s caudad while the spring moult begins on the flanks and proceeds both cephalad and caudad. In fawn b i r t h coat the moult i s caudad. The factors responsible for i t are not known. The extent to which the formation of new hair acts as a physiological or physical stimulus i n shedding of the old h a i r i s also of inte r e s t , i n investigating moult patterns. It would also be of great significance to f i n d out i f there i s any phase difference i n a c t i v i t y of hair f o l l i c l e s over d i f f e r e n t regions of the body and the e f f e c t of any that t h i s has on the timing and the d i r e c t i o n of the moult. Ling (1965) has r i g h t l y stressed the need to investigate these aspects. The d i r e c t i o n of moult i n the deer fawn has been discussed e a r l i e r . No corresponding observations are available on young ones of goat and c a t t l e . Ryder ( i960) has stated that the b i r t h coat of the mouflon was shed between four and six months of age. Here the shedding began (i n U.K.) i n August. The coat was peeling i n mats of outer hair mixed with wool. The new coat was already coming i n . During September there was b i r t h coat remaining on the shoulder, and t h i s was soon l o s t . Masses of wool from the b i r t h coat however tended to remain attached to the t i p s of the new hair coat and was l o s t when the new coat was shed the follow-1 9 3 ing spring. In Odocoileus fawn moult takes longer than i n the mouflon lamb, and there was no masses of undercoat l e f t behind. In mouflon adult Ryder ( i960) , the trend i s ventrad. The spring moult begins from the anterior and ventral parts and the l o i n s are l a s t to moult. There i s no autumn moult as such but only p a r t i a l shedding of overcoat h a i r s . In most of the domestic sheep even the spring moult has no d i r e c t i o n as such but consists of overhair and woolly masses peeling o f f . Though the wool i s dominant i n the coat, kempts have been observed to have a p a r t i a l shedding i n autumn. In Wiltshire horn sheep however Slee (1959) reports a spring moult pattern very similar to that of the mouflon. The domestic sheep at times have a tendency to shed t h e i r hairs before the new hairs, have emerged on the surface; giving r i s e to occurence of bald patches on the body. This never occurs i n mouflon, goat, c a t t l e and Odocoileus. In c a t t l e approximately four months are required to complete moult from winter to summer coat but the change over from summer to winter requires less time. In deer the duration of the moult as well as time required to complete growth i s same for both coats. But summer coat i s borne on the deer body i n r e s t i n g stage for two months as against f i v e months for the r e s t i n g winter coat. The progress of moult has not been recorded i n f u l l d e t a i l for c a t t l e . Hayman and Nay (i960) report that the new summer coat f i r s t appears on the neck and the-back of thighs and gradually extends i n area over the shoulders and the back. In Bos taurus the mid side i s the l a s t to moult, into the summer coat. In Bos  indicus however the back and the rump are the l a s t to moult into the summer coat. No d e f i n i t e moult pattern has been recorded for 1 ex-change over the summer to winter coat. Cowan ( 1 9 5 6 ) states that i n the black t a i l males normally moult a month ahead of the female with young. The female without fawns are said to moult the same time as the males. The delay i n moulting of does with fawns i s very l i k e l y due to the additional demands of l a c t a t i o n . N u t r i t i o n a l and disease stress has been known to delay moulting i n animals and therefore the l i k e l i h o o d that stress of r a i s i n g fawns brings about a delay i n moulting seems reasonable. In mammals having a delayed implantation there i s generally a r e l a t i o n s h i p betvreen implantation of the blastocyst and moulting. In deer however oestrus occurs i n the l a t t e r part of the autumn moult and the implantation a month l a t e r , the young being born when the spring moult i s complete. In c a t t l e , sheep, goat, the pelage has not been recorded to be of any behavioural s i g n i f i c a n c e . Odocoileus i s an excep-ti o n ; Cowan and Geist ( 1 9 6 1 ) report that when i n agressive state Odocoileus elevates i t s pelage as part of a threat display. The same was reported by Giest for the dorsal ridge hairs of Oreamnus display. E f f e c t of adverse n u t r i t i o n Adverse n u t r i t i o n was observed to have s i g n i f i c a n t e f f e c t on the black t a i l pelage. In experimentally starved black t a i l the large guard hairs were l o s t but no general premature shedding of the coat occurred. The experimental animals did exhbit tendency to chew off hairs from flanks exposing bare patches on the sides and considerably a f f e c t i n g the i n s u l a t i o n capacity of the pelage. I t appears however u n l i k e l y that i n the wild where 195 roughage i s available i n quantity, i f not i n qualit y , such chewing of f w i l l take place. The hairs borne by underfed animals were of smaller dimensions and had proportionately better developed cortex, which made them s l i g h t l y s t i f f . S t a t i s t i c a l analysis of data c o l l e c t e d on hair length and diameter from underfed animals and i t s subsequent regression analysis indicated that i n the und-erfed animals though the actual length and diameter was l e s s , the r e l a t i v e increase i n diameter for any unit of hair length was greater than that found i n well fed animals 1 h a i r s . Thus when the nutrients are l i m i t e d the growth i n hair diameter enjoys a p r i o r -i t y over growth i n length. Hair diameter i s primarily determined by the extent of the medulla and i t s presence also helps i n providing i n s u l a t i o n . This can be interpreted i n support of im-portance of the medulla i n providing adequate i n s u l a t i o n . A poor die t i s also supposed to reduce the breaking strength of hair f i b r e s . A test on deer f i b r e s however proved inconclusive. In course of an a r t i f i c i a l l y induced hair cycle, the pro-cess of f o l l i c l e regeneration and production of new hair i s con-siderably slower than that i n well fed animals. No delay i n moulting was observed i n the experimental black t a i l deer. In the black t a i l the rate of hair growth was much faster around biopsy sampling s i t e s , than that i n adjoining area. This has been observed i n other species and has been explained as a consequence of increased mitotic a c t i v i t y c h a r a c t e r i s t i c of areas with healing wounds Montagna (1956). However i t has not been recorded i n sheep and c a t t l e , where skin biopsies are often taken. In c a t t l e , Hayman and Nay ( i960) n u t r i t i o n a l stress i s known to prolong spring shedding. Also the proportion of p a r t i a l l y 196 medullated hairs i n the winter coat increased. In undernourished animals the winter coat had developed more rap i d l y , grew longer and was retained late on into the spring, than i n case of well fed animals. This i s i n contrast to deer. The guard hair diameter also appears to be reduced i n underfed animals. No hair shedding due to adverse n u t r i t i o n was noticed. In sheep adverse n u t r i t i o n produced no hair shedding. A decrease i n hair length was more evident than decrease i n diameter. In deer both were evident. A poor d i e t also reduces breaking strength of the hair f i b r e i n sheep. No comparable data are available for the goat. In conclusion i t can be said that the present study has revealed a number of features of the cervid p i l a r y system which was hitherto an obscure and r e l a t i v e l y unknown en t i t y . The embryological development of the f o l l i c l e s has been studies and the presence of t y l o t r i c h - l i k e f o l l i c l e s d e f i n i t i v e l y established/ A morphological study of the pelage types and the hairs that constitute them has been made and has revealed the remarkable morphometric and pigment differences i n hairs produced by the same f o l l i c l e s during the course of a year, and also i n d i f f e r e n t age-related pelages. The dynamics of the pelage i.e hair cycles and patterns of moult i n the course of a year have also been studied. The main function of cervid pelage i s assumed to be to adapt the animal to i t s environment, i n p a r t i c u l a r by providing adequate i n s u l a t i o n . In contrast t o t h e c a t t l e t h i s has been done i n deer by the presence of a well developed medulla as well as a woolly undercoat i n winter pelage. The deer summer coat has i n contrast no woolly undercoat and much smaller medulla development. 197 Adverse n u t r i t i o n has been noticed to reduce deer hair length, and diameter, as well as the capacity of the animal to regrow hairs on plucked s i t e s . However for a unit increase i n length, the r e l a t i v e increase of hair diameter was greater i n underfed animals than i n well fed animals. Thus even under stress emphasis i s put on diameter increase ( i . e . increased medulla leading to r e l a t i v e l y greater insulation) than on length may be s i g n i f i c a n t . This study has revealed few c h a r a c t e r i s t i c s of the f o l l i c l e s , h a i r , or pelage that can be regarded as of systematic s i g n i f i -cance. The two annual moults, the presence of the second glassy layer, the sinuous rather than t i g h t c o i l e d sweat gland and a l l are described only from deer and may be c h a r a c t e r i s t i c of the cervidae. However with only one species studied i n that d e t a i l t h i s cannot be c e r t a i n . A number of other c h a r a c t e r i s t i c s of the hair and pelage appear to be related to the size of the animal rather than i t s r e l a t i o n s h i p s . Thus Odocolleus resembles the size similar to that of goat and sheep more c l o s e l y than i t does c a t t l e i n many aspects of hair and pelage. 198 BIBLIOGRAPHY Addison, M.B, 1966. Skeletal development i n the black t a i l deer (Odocolleus hemlonus columbianus). M.S. t h e s i s . University of B r i t i s h Columbia. Appleyard, H.M, i 9 6 0 . Guide to i d e n t i f i c a t i o n of animal f i b r e s . Wool Industries Research Assoc. Torridon, Headingley Lane, Leeds, England. 188 pp. Auber, L., 1 9 5 ° ' The anatomy of f o l l i c l e s producing wool f i b r e s , with special reference to k e r a t i n i s a t i o n . Trans. Roy. Soc. Edin. 62: 191-254. Bandy, P.J., 1965' A study of comparative growth i n four races of black t a i l e d deer. Ph.d. the s i s . University of B r i t i s h Columbia, pp. 43-46. Billingham, R.E., 1958} A reconsideration of the phenomenon of hair neogenesis with p a r t i c u l a r reference to the healing of cutaneous wounds i n adult mammals. In "Biology of Hair  G;rowth" W. Montagna and R.A. E l l i s . Eds. pp. 451^+6B\ Bonsma, J.C. and Pret.orius, A.-J. 1943. Influence of colour and coat over ada p t a b i l i t y of c a t t l e . Fmg. S. Afr. 18.V 101-20. Bonsma, J . C , 1954. Breeding c a t t l e for increased a d a p t a b i l i t y to t r o p i c a l and subtropical environments. J. Agric. S c i . 39: 204-21 . Burns, R.H., von Bergen, W. and Young, S.S., 1962. Cashmere and undercoat of domestic and wild animals. J . Text.Inst. £3: T45-68. Butcher, E.O., 1951* Development of the p i l a r y system and the replacement of hair i n mammals. Ann. N.Y. Acad." S c i . 5 2 (2) 508-516. Camek, J., 1920. Investigations of the hair of d i f f e r e n t breeds of c a t t l e . J . Argic. S c i . 10: 12-21. Carter, H.B., 1939* Fleece density and the histology of merino skin. Australian J L. Agric. Res. 15: 210-3 . 1943. Studies i n the biology of the skin and fleece of sheep. Coun. S c i . Industr. Res. A u s t r a l i a . B u l l . No. 164. 1955. The hair f o l l i c l e group i n sheep. Anim. Breed. Abstr. 23_: 101-116. 199 Carter, H.B., 1965- Variation i n hair f o l l i c l e population of the mammalian skin. In "Biology of Skin and Hair Growth". Lyne and Short, eds. American Else v i e r Co., Inc. New York. PP. 2 5 - 3 3 . Carter, H.B., and Dowling, D.F., 1 9 5 4 . The hair f o l l i c l e and apocrine gland population of c a t t l e skin. Australian J . Agric. Res. j>: 7 4 5 - 7 5 4 . and Clarke, W.H., 1957* The hair f o l l i c l e group and skin population of Australian merino sheep. Australian J. Agric. Res. 8 : 9 1 - 1 0 8 . 1957. The hair f o l l i c l e group and skin f o l l i c l e population of some non merino "breeds of sheep.- Australian J . Agric. Res. 8 : 1 0 9 - 1 1 9 . Caton, J.D., 1877. The antelope and deer of America. Forest  and Stream PublicatlonrCo. New York. pp. 4 2 6 . Chase, H^B., 1954. Growth of h a i r . Physiol. Rev, ^ 4 : 1 1 3 - 1 2 6 . Montagna, W. and Maione, Janet D. 1 9 5 3 * Changes i n the skin i n r e l a t i o n to the hair growth cycle. Anat. Rec. 1 1 6 : 7 5 - 8 2 . Chapman, R.E., 1 9 6 5 . The ovine arrector p i l i i musculature and crimp formation i n wool. In "Biology of the Skin and Hair  Growth". Lyne, A.G. and Short, B.F. eds. New York,American Elsev i e r Co., Inc. pp. 2 0 1 - 2 3 2 Cohen, J., 1 9 6 5 . The dermal p a p i l l a . In "Biology of Skin and  Hair Growth". Au s t r a l i a , Angus and Robertson, pp. I83-I99. C o l l i n s , H.H., (1918) . Studies on normal moult and of a r t i f i -c i a l l y induced regeneration of pelage i n Peromyscus. J. exp_. Zool. 2£: 7 3 - 9 9 . Coop, I.E., 1954. Wool growth as affected by n u t r i t i o n and by climatic f a c t o r s . J. Agric. S c i . 4 ^ : 4 5 6 - 4 7 2 . Cowan, I. M c T . , 1 9 5 6 . L i f e and times of Columbian black t a i l deer. In "The Deer of North America". Taylor, W.P. ed. Stackpole, Harrisburg, Pa. pp. 5 2 3 - 6 1 7 • and Geist, V., 1 9 6 l . Aggressive behaviour i n deer of genus Odocolleus. J. Mammal. 4 2 ( 4 ) : 5 2 2 - 2 6 . Dawson, H.L. 1930. A study of hair growth i n the guinea pig. (Cavia cobaya). American J. Anat. 4 5 : 4 6 1 - 4 8 4 . Day, N.G., 1 9 6 6 . I d e n t i f i c a t i o n of hair and feather remains i n guts and faeces of stoats and weasels. J. Zool. 148: 2 0 1 - 2 1 7 . X De Meijere, J.C.H., 1894. Uber d i e Haare der Saugetiere besonders fiber i h r e Anordunng. Morph• Jb. 21: 312-424. Dolnick, E.H., 1959. Histogenesis of h a i r i n mink and i t s r e l a t i o n s h i p to dermal f o e t a l f a t c e l l s . J . Morph. 105: 1-31. Dowling, D.F., 1955* The h a i r f o l l i c l e and the apocrine gland population of Zebu (Bos i n d i c u s L) and short horn (Bos  taurus L ) , c a t t l e s k i n . A u s t r a l i a n J . A g r i c . Res. 6: 64-5-654. 1958. Seasonal changes i n coat character of c a t t l e . Proc. A u s t r a l i a n Soc. Anim. Prod. 2: 69-80. 1959* Medulation c h a r a c t e r i s t i c s of the h a i r coat as a f a c t o r i n heat tolerance of c a t t l e . A u s t r a l i a n J . A g r i c . Res. 10: 736-43. 1959. The s i g n i f i c a n c e of coat i n heat tolerance of c a t t l e . A u s t r a l i a n J . A g r i c . Res. 10: 744-48. i 9 6 0 . The s i g n i f i c a n c e of coat i n heat tolerance of c a t t l e . I I . E f f e c t of s o l a r r a d i a t i o n on body-temperature r; A u s t r a l i a n J . A g r i c . Res. 11: 8 7 - 4 . Nay, T. i 9 6 0 . C y c l i c changes i n the f o l l i c l e and h a i r coat i n c a t t l e . A u s t r a l i a n J . A g r i c . Res. 11: 1064-71. Dry, F.W., 1926. The coat of mouse. J . Genet. 16: 287-340 Duerden, J.E., 1927. E v o l u t i o n i n the f l e e c e of sheep. S. A f r . J . S c i . 24: 388-415. 1929. The zoology of the f l e e c e of sheep. S. A f r . J . S c i . 26: 459-69. and W h i t n a l l , A.B.N. 1930. Seasonal v a r i a t i o n i n the coat of some domestic mammals. S. A f r . J . S c i . 27•' 521-45. E b l i n g , F.J. and Johnson. E., 1964. The c o n t r o l of h a i r growth Symposium Z o o l . Soc, Lond. England. 12_: 97-130. F i t z p a t r i c k , T.B., Brunet, P., and K u k i t a , A. 1958. The nature of h a i r pigment. In "Biology of H a i r Growth". Montagna and E l l i s , eds. Academic Press, New York. pp. 255-303. F l e s c h , P., 1954. H a i r Growth: N u t r i t i o n a l f a c t o r s . In "Physiology and Biochemistry of the S k i n " . Rothman, S. ed. Univ. Chicago Press, Chicago, 111. pp. 601-661. F l e r o v , K.K., i 9 6 0 . Fauna of USSR mammals. Musk deer and deer Pub. I s r a e l Prog. S c i . T r a n s l . v o l . I , No. 2 . pp. 257. F r a s e r , A.H.H. 1934. Influence of n u t r i t i o n on wool growth. Nutr. Abst. Rev. 4 : 9-13. Fraser, A.S. and Nay. T., 1953* Growth of the mouse coat. I I . E f f e c t s of sex and pregnancy. A u s t r a l i a n J . B i o l . S c i . 6: 420-27. and B.F. Short, i 9 6 0 . The b i o l o g y of the f l e e c e . Melbourne, A u s t r a l i a Anim. Res. Lab. Technical Paper No. 3 . 108 pp. F r i e n d , M. and Hesselton,. w.1966. A Woolly coated white t a i l e d deer from N.I. S t a t e . J . Mammal. 4_£ (1) : 154-155. G a l p i n , N., 1935* The p r e n a t a l development of coat of New Zealand, Romney lamb. J . A g r i c . S c i . 25: 344-360. G e i s t , V., 1963. On the b e h a v i o u r of the North A m e r i c a n moose (Alces alces)Andersoni Peterson, 1950) Behaviour. 20 (3-4) 377-416. Gibbs, H.F., 1938. A study of the development of the s k i n and h a i r of the A u s t r a l i a n opossum, Trlchosurus y u l p e c u l a . Proc. Zool. Soc., Lond. England. 108: 611-648. Hamilton, J.B., ed. 1951* The growth replacement and type of h a i r s . Ann. N.Y. Acad. S c i . «£: 461-752. Hardy, M.H. 1949- The development of mouse h a i r i n v i t r o w i t h some observations on pigmentation. J . Anat. "cJj: 364-384 and Lyne, A.G., 1956. The p r e n a t a l development of wool f o l l i c l e s i n merino sheep. A u s t r a l i a n . J . B i o l . S c i . £: 423-441. Hart, J.S., 1956. Seasonal changes i n the i n s u l a t i o n of f u r . Canadian J . Z o o l . 53-57. Hausman, L.A., 1930. Recent stud i e s i n h a i r s t r u c t u r e , r e l a t i o n s h i p . S c i . Month. 30: 258-257. Hayman, R.H., 1965. Hair growth i n c a t t l e . I n " Biology of  Sk i n and Hair Growth". Lyne and Short, eds. Angus and Robertson, Sydney, A u s t r a l i a , pp. 575-590. and Nay, T., 1961. Observations on h a i r growth and shedding i n c a t t l e . A u s t r a l i a n J . A g r l . Res. 12: 513-527. Krishnan, T.S., 1939. N u t r i t i o n of sheep and wool production. Indian J . Vet. S c i . 9: 4 9 - 6 0 . L i , J.C.R., 1964. S t a t i s t i c a l i n f e r e n c e , v o l . I . Edwards Brothers Inc. Ann Arbor, Mich. 658 pp. L i n g , J.K., 1965. The integument and moulting process of the Southern Elephant s e a l , Mirounga leonln&. ( L i n n . ) - Ph.ID. t h e s i s . A u s t r a l i a n N a t i o n a l U n i v e r s i t y , Canberra. and Thomas, C.D.B., 1967« The s k i n and h a i r of the Southern Elephant s e a l . I I . P r e n a t a l and e a r l y p o s t n a t a l development and moulting. A u s t r a l i a n J . Zool. 15: 349-65. L i n s d a l e , J.M. and Tomich.P.Q., 1950. A herd of mule deer. U n i v e r s i t y of C a l i f o r n i a Press, Berkeley and Los Angeles, pp. 567. Lowenthal, A. and Montagna, W., 1955* E f f e c t of c a l o r i c r e s t r i c t i o n on s k i n and h a i r growth i n mice. J . Invest. Dermat. 24: 429-433. Lyne, A.G., 1957* Development and replacement of pelage h a i r s i n the bandicoot Perameles nasuta Geoffroy. ( M a r s u p i a l i a : Peramelidae). A u s t r a l i a n J . B i o l . S c i . 10: 197-216 1966. The development of h a i r f o l l i c l e s . A u s t r a l i a n J . S c i . v. 28 (10) : pp. 370-377-1957* The development of the epidermis and h a i r canal i n the merino sheep. A u s t r a l i a n J . B i o l . S c i . 10: 390-397. 1965. The h a i r c y c l e i n the c h i n c h i l l a . I n "BiolggycoY Skin and Hair Growth". Lyne and Short eds. American E l s e v i e r Co., Inc. New York. pp. 467-489. and Heideman, M.J., 1959. The p r e n a t a l development of s k i n and h a i r i n c a t t l e (Bos taurus. L) A u s t r a l i a n J . B i o l . S c i . 12: 72-95/ i 9 6 0 . The p r e n a t a l development of s k i n and h a i r i n c a t t l e I I . (Bos i n d i c u s L. and Bos taurus. A u s t r a l i a n J . B i o l . S c i . 13_: 5^5-599' Lyne, A.G. and Short, B.F., eds. 1965. "Biology of S k i n and Hair Growth". American E l s e v i e r Co., Inc. New York. 806 Lyndekker, R., 1898. The deer of a l l l a n d s . A h i s t o r y of the f a m i l y cervidae l i v i n g and e x t i n c t . London, England. Mahal, G.S., Johnston, A. and Burns, R.L. 1951. Types and dimensions of f i b r e scales from the wool types of domestic sheep, and w i l d l i f e . Text. Res. J . 21 ( 2 ) : 8 3 - 8 9 . Manby, J . , 1932. An improved method f o r r e v e a l i n g the scale s t r u c t u r e of wool and h a i r . J . Text I n s t . 2 3 : T5« Margolena, L.A., 1959* Skin and h a i r f o l l i c l e development i n d a i r y goats. V i r g i n . J . S c i . 10: 33-47 203 Mayer, W.V., 1952. The hair of C a l i f o r n i a mammals with keys to the dorsal guard hairs of C a l i f o r n i a mammals. Amer. Midi. Nat. 4 8 : 480-512. Montagna, W., 1962. The structure and function of skin. Academic Press, New York. 356 pp. and E l l i s , eds. 1958. The biology of hair growth. Academic Press, New York. 520 pp. Mohn, M.P., 1958. The effects of d i f f e r e n t hormal states on the growth of hair i n r a t s . Montagna, W. and E l l i s , R.A. eds. In "Biology of Hair Growth". Adademic Press, New York. pp. 335-398. Murie, O.J., 1951. The elk of North America. W i l d l i f e Management I n s t i t u t e . Washington, D.C. and Stackpole Co., Harrisburg, Pa. 376 pp. Nay, T. and Fraser, A.S., 1954. Growth of mouse coat. I I I . Australian J . B i o l . S c i . ?: 361-367. 1955« Growth of mouse coat. V. e f f e c t s of pregnancy and l a c t a t i o n . Australian J . B i o l . S c i . 8 : 4 2 8 - 4 3 3 . and Hayman, R.H., 1963. Some skin characters i n f i v e breeds of European (Bos taurus L.) dairy c a t t l e . Australian J. Agric. Res. 1 4 : 294-302. Noback, C.R., 1951* Morphology and phylogeny of h a i r . Ann. N.Y. Acad. S c i . £3: 476-492. Pan, Y.S. 1964. Variation i n hair characters over the body i n Sahiwal Zebu and Jersey c a t t l e . Australian J . Agric. Res. 1£: 3 4 6 - 5 6 . P a r n e l l , J.P., 1951 ' Hair pattern and d i s t r i b u t i o n i n mammal. Ann. N.Y. Acad. S c i . 4 9 3 - 4 9 7 . Peterson, R.L., 1955* North American moose. University of Toronto Press, Toronto, Ont. 2|0 pp. P r i e s t l y , G.C. and Rudall, K.M., Modification i n the Huxley's layer associated with changes i n f i b r e diameter and output. In "Biology of Skin and Hair Growth". Lyne, A.G. and B.F. Short, eds. American E l s e v i e r Co., Inc. New York, pp. 165-170. Rand, R.W., 1956. The Cape fur seal Arctocephalus p u s i l l u s (Schreber), i t s general c h a r a c t e r i s t i c s and moult. S. Afr. Div. F i s h . Invest. Rep. No. 2 1 . 204 Rook, A. and Champion, R.N., eds. 1964. Progress i n b i o l o g i c a l sciences i n r e l a t i o n to dermatology. Cambridge University Press, v o l . 2 . pp. 499 . Rothman, S., 1954. Physiology and biochemistry of skin. University of Chicago Press, Chicago, 111. pp. 1958. Introduction. In 11 Biology of Hair Growth". Montagna, W. and E l l i s , R.E., eds. Academic Press, New York. pp. x l to x l l . Ryder, M.L. 1956. N u t r i t i o n a l and seasonal changes i n the fleece of some sheep. J . Agric. S c i . 47: 129-144. 1957. A survey of the f o l l i c l e population i n a range of B r i t i s h breeds of sheep. J . Agric. S c i . 4 9 : 275-284. 1956. Observations on n u t r i t i o n a l and seasonal changes i n the fleece of some Masham sheep. J . Agric. S c i . 42: 187-190. 1958. F o l l i c l e arrangement i n skin from wild sheep, primitive domestic sheep and i n parchment. Nature. 182: 781-783. 1958. N u t r i t i o n a l factors influencing hair and wool growth. Montagna, V/. and E l l i s , R.E., eds. In "Biology of Hair Growth". Academic Press, pp. 305-334. i 9 6 0 . A study of the coat of the Mouflon ovls musimon with s p e c i a l reference to seasonal change. Proc. Zool. Soc, Lond. Eng. 135: 387-408. 1964. Moulting and hair replacement. In Progress i n the b i o l o g i c a l sciences i n r e l a t i o n to dermatology. Rook, A. and Champion, R.H., eds. Cambridge University Press, Cambridge, v o l . 2 . pp. 325-335-1966. Coat structure and seasonal shedding i n goats. Anim. Prod. 8: 289-302. Sar, H. and Calhoun, M. Lois., 1965. Microscopic anatomy of the integument of common American goat. American J . Vet. Res. 22 ( 1 1 7 ) : 444-456. Scheffer, B.V. 1962. Pelage and surface topography of the Northern fur se a l . N. American Faun Ser. 64 U.S. Fish and W i l d l i f e Service. Schleger, A.V. and Turner, H.G., i 9 6 0 . Analysis of coat characters of c a t t l e . Australian J . Agric. Res. 11: 875-885. Scholander, P.F., Walters, V., Hock, R. and Irving, L. Body in s u l a t i o n of some a r c t i c and t r o p i c a l mammals. B i o l . B u l l . £2: 225-236. 205 Segall, A. Ueber die Entwicklung und den Wechsel der Haare beim Meerschweinchen (Cavia cobaya Schreb.) Arch, mlkr. Anat. CO.: 218-291. Severlnghaus, C , and Chaetum, E., 1956. L i f e and times of the white t a i l e d deer. Taylor, W. ed. In "The Deer of North  America". Wild l i f e Management Inst. Washington, D.C. and Stackpole,Company, Harrisburg, Pa. pp. 57-186. Simpson, G.G., 194-5• The p r i n c i p l e s of c l a s s i f i c a t i o n and a c l a s s i f i c a t i o n of mammals. B u l l . American Mus. 8jj_: 1-350. Slee, J., 1965. Seasonal pattern of moulting i n Wiltshire sheep. In., " Biology of Skin and Hair Growth". Lyne, A.G., and Short, B.P., eds. American E l s e v i e r Pub. Company, New York. PP. 5^5-563. Sokolov. W., 1963. The skin structure i n wild Artio-dactyla of USSR fauna. l 6 t h Int. Zool. Cong. Washington, D.C. p. 167. Spence, L.E., 1963. Study of i d e n t i f y i n g c h a r a c t e r i s t i c s of mammal h a i r . Wyoming Game and Fish Commission. Job., Compl. Rep. 121 pp. Stains, H.J., 1958. Key to guard hairs of middle west fur bearers. J . W i l d l . Mgmt. 2 2 ( 1 ) : 95-97. S t r a i l e , V I .E., i 9 6 0 . Sensory hair f o l l i c l e s i n mammalian, skin. The T y l o t r i c h s . American J . Anat. 106(2:).: 1133-148 I96I. The morphology of t y l o t r i c h f o l l i c l e s i n the skin of the rabbit. American J . Anat. 109: 1-14. 1965' Root sheath dermal p a p i l l a r e l a t i o n s h i p and the control of hair growth. In "Biology of Skin and  Hair Growth"I Lyne, A.g., and Short, B.F., eds. American f l s e v l e r pub. Company, New York. pp. 35-57. Taylor, W.,.ed. 1956. The deer of North America. Wild L i f e Management Inst. Washington, D.C. and Stackpole Company, Harrisburg, Pa. 668 pp. Van Koetsveld, E., 195^. Influence of feeding on the coat and i t s structure i n animals. Ti.jdschr. Dlergeneesh. 79: 4-05-16. Wildman, A.B., 1932. Coat and f i b r e development i n some B r i t i s h sheep.. Proc. Zool. Soc. Lond. Eng. ( 1 ) : 257-285. 1937. Non s p e c i f i c i t y of t r i o f o l l i c l e s i n the merino. Nature. .14 0: '8'^ 1--'8Q2. 1954. The microscopy of animal t e x t i l e f i b r e s . Wool Indust. Res. Assoc. Leeds, England. 1957. C l a s s i f i c a t i o n of wool f o l l i c l e s i n sheep. Nature 180: 99-100. 206 Yeats, N.T.M., 1954. Environmental control of coat change i n Cattle. Nature. 1_7_4: 609-610. 1955' Photoperiodicity i n c a t t l e . I. Seasonal changes i n coat character and the i r importance i n heat regulation. Australian J . Agrl• Res. 6: 891-902. 1957. Photoperiodicity i n c a t t l e . I I . The equatorial l i g h t environment and i t s e f f e c t on the coat of European c a t t l e . Australian J . Agric. Res. 8: 733-739. APPENDIX I Date 2 7 Aug 6 6 3 r d Sept. 6 6 9 t h Sept. 6 6 1 7 Sept. 6 6 24 Sept. 6 6 1 s t Oct. 6 6 8 Oct. 6 6 1 5 Oct. 6 6 2 2 Oct. 6 6 2 9 Oct. 6 6 5 Nov. 6 6 1 2 Nov. 6 6 2 6 Nov. 6 6 2 Dec. 6 6 1 0 Dec. 6 6 1 7 Dec. 6 6 24 Dec. 6 6 7 Jan. 6 7 14 Jan. 6 7 2 2 Jan. 6 7 2 7 Jan. 6 7 4 Feb. 6 7 18 Feb. 6 7 2 5 Feb. 6 7 4 March 6 7 1 2 March 6 7 18 March 6 7 2 5 March 6 7 18 A p r i l 6 7 8 A p r i l 6 7 1 5 A p r i l 6 7 2 2 A p r i l 6 7 2 9 A p r i l 6 7 6 t h May 6 7 1 3 May 6 7 18 May 6 7 1 0 June 6 7 1 s t July 6 7 8 July 6 7 1 5 July 6 7 WEEKLY WEIGHT DATA Ul6 TR U26 w4 194 160 184 127 199 160 191 132 190.5 161 192 138 194 160 192 138 192 160 201 14 0 193 160 201 140 190 160 202 142 186 162 207 145 183 160 202 144 176 156 200 146 172 i4o 195 142 164 - 192 138 155 - 195 142 154 128 185 126 154 - 182 124 147 - 179 120 142 128 176 121 143 128 176 121 146 - 175 121 146 — 176 121 147 — 174 123 147 - 173 121 148 125 170 124 148 160 126 147 126 160 126 150 — 166 128 151 - 166 128 152 125 166 130 154 125 164 131 154 126 164 132 156 125 160 132 158 127 168 134 158 127 168 134 159 127 168 134 159 - 170 137 159 127 170 139 155 123 171 142 158 125 176 147 158 122 178 148 157 122 177 153 Date 1 9 6 6 Aug. 2 6 to Sept. 1 Sept. 2 to Sept. 8 Sept. 9 to Sept. 1 5 Sept. 1 6 to Sept. 2 1 Sept. 2 2 to Sept. 28 Sept. 2 9 to Oct. 5 Oct. 6 to Oct. 1 2 Oct. 1 3 to Oct. 1 9 Oct. 2 0 to Oct.;? 2 6 Oct. 2 7 to Nov. 2 Nov. 3 to Nov. 9 Nov. 1 0 to Nov. 1 6 208 APPENDIX II  FEED INTAKE IN CALORIES (WEEKLY AVERAGE) U l 6 Tg U26 W4 4685 .20 4673 .13 7124.11 6527.26 4 6 0 9 . 7 1 4571.54 5828.82 5803 .73 4317.64 3 6 4 4 . 5 9 6 1 0 8 . 1 6 5 6 3 3 . 7 3 3 9 4 9 . 3 7 3809.68 13803.15 5 1 1 7 . 6 7 3 1 4 9 . 3 3 3 1 1 1 . 2 4 5 8 4 1 . 5 2 5 5 8 4 . 2 7 2 5 6 5 . I 8 2641.38 5193.87 5 2 9 5 . 4 6 2742.97 6285.98 5H7.67 5740 .24 2146.11 2209 .61 4139.85 4 8 7 6 . 4 6 2031.82 2 0 4 4 . 5 2 2806.4 4 8 7 6 . 3 9 1 9 6 8 . 3 3 3 9 3 . 6 6 2349 .30 4762 .10 2 3 2 3 . 8 9 9 1 4 . 0 3 2781.06 5041.48 2311 .21 177 .78 2 9 4 6 . 1 5 4089 .06 APPENDIX II (cont'd) FEED INTAKE IN CALORIES (WEEKLY AVERAGE) 209 Date 1966 Ul6 TR U26 w4 . Nov... to Nov. .17 22 2311.21 179.0 2844.69 4000.17 Nov. to Nov. 23 29 2514.41 747.96 3212.83 4317.64 Nov. to Dec. 30 6 3136.64 1981.09 3581.10 5651.03 Dee. to Dec. 7 13 5592.92 2539.78 3873.17 5270.05 Dec. to Dec. 14 20 2869.96 2435.20 3365.21 5790.72 Dec. to Dec. 21 27 4038.26 3060.44 3708.09 5689.12 Dec. to Jan. 28 3 5765.32 2488.99 3657.29 6222.49 1967 Jan. to Jan. 4 10 5562.14 2857.26 4228.75 5857.17 Jan. to Jan. 11 17 5790.72 2374.71 3898.57 3644.69 Jan. to Jan. 18 24 5041.48 2958.85 4470.03 5065.29 Jan. to Jan. 25 31 4876.39 2412.79 4863.69 4330.34 Feb. to Feb. 1 7 5854.22 2285.80 4063.57 3923.79 210 APPENDIX II (cont»d) FEED INTAKE IN CALORIES (WEEKLY AVERAGE) Date 1967 Feb. 8 to Feb. 14 Feb. 15 to Feb. 21 Feb. 22 to Feb. 28 March 1 to March 7 March 8 to March 14 March 15 to March 21 March 22 to March 28 March 29 to A p r i l 4 A p r i l 5 to A p r i l 11 A p r i l 12 to A p r i l 18 A p r i l 19 to A p r i l 25 A p r i l 26 to May 2 U16 TR U26 w4 5346.34 5155.77 5562.14 5866.92 5460.55 5689.44 5816412 5358.95 5155.77 5033.38 4749.70 4495.42 2376.69 3123.93 2463.59 2552.48 2679.47 2946.15 3238.74 2933.46 2933.46 2984.25 3085.84 3009.65 4063.57 4076.36 4076.36 3822.38 4216.05 3736.49 3784.28 3467.38 3923.97 4127.15 3923.97 3911.27 3949.37 4216.05 4266.84 4177.95 4622.41 3949.30 4139.89 4558.92 4203.35 4367.17 4203.35 4139.85 2 1 1 " Date 1967 APPENDIX II (cont»d) FEED INTAKE IN CALORIES (WEEKLY AVERAGE) V U l 6 TR U26 W4 May 3 to May 9 May 10 to May 16 May 17 to May 23 May 24 to May 30 May 31 to June 6 June 7 to June 13 June 14 to June 20 June 21 to June 27 June 28 to July 4 July 5 to July 11 July 12 to July 18 July 19 to July 25 July 26 to July 31 4292.24 4089.06 3987.47 3911.28 3987.47 3962.07 4089.06 4089.06 4089.06 4089.06 4089.06 4089.06 4089.06 2933.46 2933.46 2831.92 2755.67 2755.67 2986.25 2933.46 2933.46 2984.25 2933.46 2933.46 2933.46 2933-46 3809.08 3708.08 3835.08 4038.26 4419.23 6381.13 3923.97 3923.97 4774.80 4863.69 4749.40 5295.46 5126.14 4139.86 4812.90 4089.05 3987.47 4660.57 4647.81 4419.23 4419.23 4431.93 5041.48 4914.49 5295.46 5052.06 212 APPENDIX III HISTOLOGICAL TREATMENT Skin biopsy samples taken by means of a trephine were fixe d i n Bouin"s f l u i d for 24 hours and transferred to 70% alcohol for storage. The f o e t a l material available was already fi x e d and preserved i n formol s a l i n e . Subsequently the f i x e d material was treated as follows. Where hairs were present they were cut by means of f i n e s u r g i c a l scissors as close to the skin surface as possible, taking care to leave enough length to adequately indicate the hair o r i e n t a t i o n v i s a v i s the skin surface. Using a sharp single edge ("Gem") safety razer blade and a dissecting micro-scope the tissue material was halved into two along the plane of the h a i r s . As f a r as possible attempt was made to cut the hair f o l l i c l e s along t h e i r whole length. The material so:out was dehydrated and cleared i n a Tissue Tek Automatic tissue processing machine, using the following routine:-W-AX EMBEDDING SKIN Foetal SKIN Adult 10% Formalin 70% Alcohol ( i ) 70% Alcohol ( i i ) 90% Alcohol ( i ) 90% Alcohol ( i i ) Absolute Alcohol ( i ) Absolute Alcohol ( i i ) Absolute Alcohol ( i i i ) Xylene or Chloroform ( i ) Xylene or Chloroform ( i i ) Wax (i) Wax + 5% Bees wax ( i i ) 1V2 hrs. l l / 2 hrs. Storage 24 hrs. 4 hrs. 2 hrs. 2 hrs. 1 hr. 1 hr. 1 hr. 2 hrs. 2 hrs. 1V2 hrs. l V 2 hrs. Storage 24 hrs. 4 hrs. 2 hrs. 2 hrs. 1 hr. 1 hr. 1 hr. 4 hrs. 4 hrs. 18 hrs. 2.2 "hrs. 213 Of the two portions of each sample,, one was embedded i n wax with i t s l o n g i t u d i n a l l y cut surface facing the base of the mould, while i n case of the other half i t was the skin surface which was facing the mould base. The blocks were duly l a b e l l e d . On sectioning, the former gave longitudinal section of the hair f o l l i c l e s while the l a t t e r gave surface (Transverse sectioni). 8 to 10/*- thick sections were cut on a rotary microtome, mounted, and stained as follows using the following methods. a) Haematoxylin and eosin b) Mallory's t r i p l e s t ain: a rapid one step method. (Cason, J.E., 1950. Stain Technology, 2j>: p. 225) c) Verhoeff's and Van Giesons method. Gurr (1952) Skin samples were also taken from tanned deer hides (Summer coat and winter coat) and were treated as follows:-The samples were, placed i n a 0.5$ solution of trisodium phosphate for three days, dehydrated v i a alcohol and cleared i n cedarwooxl o i l and embedded i n 5 6 0 M. Pt. wax. The blocks were sectioned at 8/*- to 10/*' and sections stained with Haematoxylin and eosin. APPENDIX IV KEY TO ABBREVIATIONS USED IN ILLUSTRATIONS Ap Arrector p i l i i muscle Bf Branching f o l l i c l e s CR" Club hair CO Cortex Cp Central primary f o l l i c l e Cts Connective tissue sheath Cap Capsule CIGF Central intermediate guard hair f o l l i c l e D Dermis Dp Dermal p a p i l l a D i l . p . Dilated portion DDC Dedifferentiated c e l l s E Epidermis ES Ental swelling F Fibrocytes FB F o l l i c l e bulb FF F o l l i c l e folds FS F i r s t formed secondary f o l l i c l e F i b Fibres FBS F o l l i c l e base Fan F o l l i c l e anlagen GF Growing f o l l i c l e GM Glassy membrane Gr C e l l s containing 'Keratohyaline granules H Keratinized hair HC Hair canal He" Henle 1 s layer HN Hair cone Hu Huxley 1s layer HF Hair f o l l i c l e Hcu Hair c u t i c l e IS Internal root sheath IGH Intermediate guard hairs ISC Internal root sheath c u t i c l e Int.Ca I n t r a c e l l u l a r c a v i t i e s LP Lateral primary f o l l i c l e s LS Later formed secondary f o l l i c l e Lu Lumen LGH Large guard hairs LGHF Large guard hair f o l l i c l e LIGF Lateral intermediate guard h a i r f o l l i c l e s M Medulla Mec Mesenchymal c e l l s Mel Melanocytes NH New hair 215 APPENDIX IV (cont'd) OS Outer sheath (External root sheath) p Periderm PP Paired f o l l i c l e s PP Pre p a p i l l a PLF Plucked f o l l i c l e SbC Sebaceous c e l l s SbG Sebaceous gland SC Stratum corneum SGe Stratum germinativum SGr Stratum granulosum Sb 0 Sebaceous gland opening SSP Stratum spinosum SWD Sweat duct SWG Sweat gland SW 0 Sweat gland opening T Trio grouping' Tr T r a n s i t i o n a l hair UDC Undifferentiated c e l l s WtpF White tipped hair f o l l i c l e s WtP White tipped hair WuH Woolly under hair 

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