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A study of comparative growth in four races of black-tailed deer Bandy, Percy John 1965

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The Uni v e r s i t y FACULTY OF of B r i t i s h Columbia GRADUATE STUDIES PROGRAMME OF THE FINAL ORAL EXAMINATION FOR THE DEGREE OF DOCTOR OF PHILOSOPHY of PERCY JOHN BANDY B„A„, The University of B r i t i s h Columbia, 1952 M,A„ s.The University of B r i t i s h Columbia, 19.55 TUESDAY, May 4, 1965., AT 4:00 P„M„ IN ROOM 3332, BIOLOGICAL SCIENCES BUILDING COMMITTEE IN CHARGE Chairman: L MoT. Cowan J. R. Adams W„ D„ K i t t s P, A. Dehnel H.„ C, Nordan W, S. Hoar A. J„ Wood External. Examiner; H. K 0 Buechner Department, of Zoology Washington State University Pullman, Washington A STUDY OF COMPARATIVE GROWTH IN FOUR RACES OF BLACK-TAILED DEER ABSTRACT Four r a c i a l stocks of B l a c k - t a i l e d deer, captured as fawns i n t h e i r native habitat, were raised under co n t r o l l e d n u t r i t i o n a l conditions at f a c i l i t i e s of the University of B r i t i s h Columbia. Q u a l i t a t i v e l y complete l i q u i d and s o l i d diets were fed i s o c a l l o r l c a l l y on two planes of n u t r i t i o n ; a high plane designed to evoke expression of the maximum genetic p o t e n t i a l for growth; a low plane designed to reduce growth to a minimum,, Body weights and c e r t a i n l i n e a r measurements were recorded at i n t e r v a l s and the resultant data were used for comparisons of growth parameters r e l a t e d to sex, plane of n u t r i t i o n and r a c i a l o r i g i n . Weight growth curves were found to fluc t u a t e seasonally i n correspondance to changes i n ph y s i o l o g i c a l conditions associated with reproduction. In addition, i t was found that growth i n both sexes was suppressed by the winter environment i n s p i t e of constancy i n the d a i l y d i e t . Low plane deer showed p o s i t i v e growth responses during the winter thereby i n d i c a t i n g that growth i s not suppressed to the same degree i n animals which have not attained t h e i r seasonal maximum, weights through.undernourishment. Linear growth curves exhibited no seasonal depres-sions as they increased continuously from b i r t h to t h e i r respective mature s i z e s . In contrast to body weight, the mature s i z e of a l l l i n e a r measurements, except chest g i r t h were not s i g n i f i c a n t l y affected by the plane of n u t r i t i o n . The rates of growth, however, were reduced by the low plane, thereby increasing the age at which mature s i z e was attained. The r e l a t i v e proportions at mature size of l i n e a r measurements were not affected by the plane of n u t r i t i o n . S l i g h t a l t e r a t i o n s i n proportions were noted f o r several r a t i o s but the only s i g n i f i c a n t d i f f e r e n c e occurred i n the chest g i r t h / h i n d leg length r a t i o . The development of s i g n i f i c a n t differences between planes of n u t r i t i o n with regard to t h i s r a t i o indicates that i t might be useful i n q u a n t i t a t i v e l y determining condition i n wild populations. S i g n i f i c a n t sexual differences i n the head length/ head width r a t i o at maturity showed that the head length did not d i f f e r i n s i z e whereas the remaining measurements were reduced i n magnitude for female deer. Thus the com-ponents of head length-appear to escape the l i m i t a t i o n s imposed by the female upon growth of a l l other parts measured. Parameters of growth such as the instantaneous r e l a t i v e rate of growth, the instantaneous r e l a t i v e rate of decline i n growth, mature size, age and weight at i n f l e c t i o n s age at maturity, and others have been compu-ted f or each race, sex and plane of n u t r i t i o n . Para-meters derived from, the growth patterns of all. four races demonstrate that each race d i f f e r s from the others i n one or more aspects of t h e i r growth response i n a given set of environmental conditions. The Mule deer i s poten-t i a l l y the largest and f a s t e s t growing, followed i n turn by the Sitka B l a c k - t a i l , the C a l i f o r n i a n stock and the Vancouver Island stock of the Columbian B l a c k - t a i l e d deer. This and other c h a r a c t e r i s t i c s of growth i n d i c a t e that the C a l i f o r n i a n and Vancouver Island stocks of the Columbian B l a c k - t a i l e d deer may be separable at the sub-s p e c i f i c l e v e l . No r a c i a l differences could be shown, however, i n the e f f i c i e n c i e s of the growth processes. GRADUATE STUDIES F i e l d of Study: Zoology Special Advanced Course i n Zoology Comparative Ethology F i s h e r i e s Biology and Management Intermediary Metabolism. Enzymology Endocrinology Molecular Structure and B i o l o g i c a l I. McT. Cowan D. F, Udvardy W. S. Hoar P 0 A„ Larkin S« H. Zbarsky W. J. Polglase M, Darrach Function W0 Jo Polglase PUBLICATIONS 1= Bandy, P.J. 1955. Studies of growth and n u t r i t i o n i n *" Columbian B l a c k - t a i l e d deer, (Odocoileus hemionus columbianus). M.A. Thesis, The Un i v e r s i t y of B r i t i s h Columbia 2. Bandy, P.J., I.McT. Cowan, W.D. K i t t s and A.J. Wood.l' A method for the assessment of the n u t r i t i o n a l statu of wild ungulates. Can.J-.Zool. 34:46-52 3. K i t t s , W.D., I.McT. Cowan, P.J. Bandy and A.J. Wood.H'" The immediate post-natal growth i n the Columbian Bit-t a i l e d deer i n r e l a t i o n to the composition of the milk of the doe. J . Wildl.Mgmt. 20(2) : 212-214 4. K i t t s , W.D., P.J« Bandy, A.J. Wood and I.McT. Cowan.1956. E f f e c t of age and plane of n u t r i t i o n on the blood chemi-stry of the Columbian B l a c k - t a i l e d deer, (Odocoileus  hemionus columbianus.).. A. Packed c e l l volume sedimenta-t i o n rate and hemoglobin. C.J. Zool. 34:477-484. 5. Bandy, P.J., W0D. K i t t s , A.J, Wood and I.McT. Cowan.1.. The e f f e c t of age and the plane of n u t r i t i o n on the blood chemistry of Columbian B l a c k - t a i l e d deer, (Odo-coileus hemionus columbianus). B. Blood glucose, non-protein nitrogen, t o t a l plasma protein, plasma album 1 g l o b u l i n and fibrinogen. Can.J.Zool. 15:283-289. A STUDY OF COMPARATIVE GROWTH IN FOUR RACES OF BLACK-TAILED DEER by PERCY JOHN BANDY M.A., University of B r i t i s h Columbia, 1955 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in the Department of Zoology We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1965 XV In presenting th i s thes is i n p a r t i a l f u l f i lment of the requirements for an advanced degree at the Univers i ty of B r i t i s h Columbia, I agree that the L ibrary s h a l l make i t f ree l y ava i lab le for reference and study. I further agree that permission for extensive copying of th i s thesis for scho lar ly purposes may be granted by the Head of my Depart-ment or by h i s representatives. I t i s understood that copying or pub l icat ion of th i s thesis for f i n a n c i a l gain s h a l l not be allowed without my wr i t ten permission. Department of ZQQLQGY The Univers i ty of B r i t i s h Columbia, Vancouver 8, Canada Date A r j r i l A _ 1 9 6 5 Chairman, Dean I . McT. Cowan i i ABSTRACT A STUDY OF COMPARATIVE GROWTH IN FOUR RACES OF BLACK-TAILED DEER Four r a c i a l stocks of Bl a c k - t a i l e d deer, captured as fawns i n the i r native habitat, were raised under control-led n u t r i t i o n a l conditions at f a c i l i t i e s of the University of B r i t i s h Columbia. Q u a l i t a t i v e l y complete l i q u i d and s o l i d diets were fed i s o c a l l o r i c a l l y on two planes of n u t r i -tion; a high plane designed to evoke expression of the maximum genetic pote n t i a l for growth; a low plane designed to reduce growth to a minimum. Body weights and certa i n l i n e a r measurements were recorded at i n t e r v a l s and the resultant data were used for comparisons of growth param-eters related to sex, plane of n u t r i t i o n and r a c i a l o r i g i n . Weight growth curves were found to fluctuate seasonally i n correspondance to changes i n physiological conditions associated with reproduction. In addition, i t was found that growth i n both sexes was suppressed by the winter environment i n spite of constancy i n the da i l y diet. Low plane deer showed po s i t i v e growth responses during the winter thereby in d i c a t i n g that growth i s not suppressed to the same degree i n animals which have not attained t h e i r seasonal maximum weights through undernourishment. Linear growth curves exhibited no seasonal depressions as they increased continuously from b i r t h to their respective mature sizes. In contrast to body weight, i i i the mature siz e of a l l li n e a r measurements, except chest g i r t h were not s i g n i f i c a n t l y affected by the plane of n u t r i t i o n . The rates of growth, however, were reduced by the low plane thereby increasing the age at which mature size was attained. The r e l a t i v e proportions at mature size of li n e a r measurements were not affected by the plane of n u t r i t i o n . S l i g h t a l t e r a t i o n s i n proportions were noted for several r a t i o s but the only s i g n i f i c a n t difference occurred i n the chest girth/hind leg length r a t i o . The development of s i g -n i f i c a n t differences between planes of n u t r i t i o n with regard to t h i s r a t i o indicates that i t might be useful i n quanti t a t i v e l y determining condition i n wild populations. S i g n i f i c a n t sexual differences i n the head length/head width r a t i o at maturity showed that the head length did not d i f f e r i n si z e whereas the remaining measurements were reduced i n magnitude for female deer. Thus the components of head length appear to escape the l i m i t a t i o n s imposed by the female upon growth of a l l other parts measured. Parameters of growth such as the instantaneous r e l a t i v e rate of growth, the instantaneous r e l a t i v e rate of decline i n growth, mature size , age and weight at i n f l e c -tion, age at maturity, and others have been computed for each race, sex and plane of n u t r i t i o n . Parameters derived i v from the growth patterns of a l l four races demonstrate that each race d i f f e r s from the others i n one or more aspects of t h e i r growth response i n a given set of environmental con-d i t i o n s . The Mule deer i s p o t e n t i a l l y the largest and f a s t e s t growing, followed i n turn by the Sitka B l a c k - t a i l , the C a l i f o r n i a n stock and the Vancouver Island stock of the Columbian B l a c k - t a i l e d deer. This and other c h a r a c t e r i s t i c s of growth indicate that the C a l i f o r n i a n and Vancouver Island stocks of the Columbian B l a c k - t a i l e d deer may be separable at the sub-specific l e v e l . No r a c i a l differences could be shown, however, i n the e f f i c i e n c i e s of the growth processes. V TABLE OF CONTENTS Page INTRODUCTION 1 MATERIALS AND METHODS 10 Experimental Animals and Their Care. . 10 Planes of Nu t r i t i o n 13 Body Weights and Measurements 18 An a l y t i c a l Methods for Growth i n Body Weight 19 A n a l y t i c a l Methods for Linear Measurements 32 RESULTS 37 The Experimental Deer Herd 37 Food Consumption 39 M o r t a l i t i e s and Their Causes . 40 Parasites, Infections, Diseases and Treatment 42 The E f f e c t of Plane of Nu t r i t i o n on Condition and Behaviour. 43 Body Weights and Linear Measurements 46 DISCUSSION 48 PART I. PATTERNS OF GROWTH IN BODY WEIGHT FOR INDIVIDUAL DEER OF EACH RACE Weight Growth of High Plane Male Black-t a i l e d Deer 48 Sexual Differences i n the Actual and E f f e c t i v e Growth Patterns of High Plane Deer . 59 The Seasonal P e r i o d i c i t y of Growth 62 The E f f e c t of a Low Plane of Nut r i t i o n on Growth 69 Instantaneous Relative Rates of Increase for Summer Growth . 78 v i Page PART. I I . RACIAL COMPARISONS OF THE INSTANTANEOUS RELATIVE RATES OF GROWTH IN BODY WEIGHT Comparison of Four Races of Bl a c k - t a i l e d Deer With Respect to the E f f e c t i v e Growth of Body Weight i n High Plane Males 83 The Instantaneous Relative Growth Rates of High Plane Female Deer of Four Races . . . . 96 The Instantaneous Relative Growth Rates of Four Races of Male B l a c k - t a i l e d Deer on Low Plane Feeding . 99 PART III . PATTERNS OF LINEAR GROWTH FOR INDI-VIDUAL DEER OF EACH RACE Growth Curves of Some Linear Body Dim-ensions 107 Size at B i r t h i n Relation to the F i n i t e Size for Various Linear Measurements 114 Rates of Growth of Certain Linear Elements. 117 PART IV. GROUP COMPARISONS OF PARAMETERS DERIVED FROM GROWTH IN LINEAR SIZE The E f f e c t of Sex Upon the Regression C o e f f i c i e n t s and Constants of Age Related Linear Growth 123 The E f f e c t of the Plane of Nu t r i t i o n Upon the Growth of Linear Measurements 131 The E f f e c t of Sex and the Plane of Nu t r i -tion Upon the Age at Which Mature Size i s Attained 137 The E f f e c t of Sex and the Plane of Nu t r i -tion; Upon the Relative Proportions of Certain Linear Measurements 143 Comparative Linear Growth Charact e r i s t i c s of Four Races of Bla c k - t a i l e d Deer 147 CONCLUSIONS 156 LITERATURE CITED 170 APPENDIX 175 v i i LI ST OF TABLES Table Page I. Absolute gains i n 10 to 40 day periods for two high plane bucks (No. 92, Mule deer, and No. 51, Columbian Black-t a i l ) 23 II. Values of the multiple c o r r e l a t i o n c o e f f i c i e n t (RSQ) determined for t r i a l values of A i n the equation L = A -Be~ k t 33 I I I . The standard error of estimates (SYfc) and multiple c o r r e l a t i o n c o e f f i c i e n t s (Rfc2) for l i n e a r measurements, and planes of n u t r i t i o n for the Vancouver Island race 35 IV. The d i s t r i b u t i o n of experimental deer with respect to race, sex and the plane of n u t r i t i o n 38 V. Instantaneous r e l a t i v e growth rates (k), and corresponding absolute rates of gain (lbs per day) for periods of rapid summer growth 80 VI. Instantaneous r e l a t i v e growth rates of high plane male deer of four races, i n the s e l f - a c c e l e r a t i n g phase of eff e c -t i v e growth (k x 100) . &5 VII. Instantaneous r e l a t i v e growth rates for high plane male deer of four races i n the s e l f - i n h i b i t i n g phase of e f f e c t i v e growth showing estimated mature weights. . . 86 VIII. Age at ultimate weight (A) and weights at the i n t e r s e c t i o n of f i t t e d s e l f -accelerating and s e l f - i n h i b i t i n g curves. . . §MJ IX. Ch a r a c t e r i s t i c s of growth patterns of i n d i v i d u a l high plane male deer of four races arranged i n descending order of magnitude of the value of k S9 X. Growth c h a r a c t e r i s t i c s of indiv i d u a l s arranged i n a si m i l a r descending series of both k and -k values 9.1 v i i i Table Page XI. Ch a r a c t e r i s t i c s of growth patterns of i n d i v i d u a l male deer of four races arranged i n descending order of magni-tude of the value of -k. . . . . . . . . . . . . . . 93 XII. C h a r a c t e r i s t i c s of growth patterns of deer demonstrating r e l a t i v e l y high phase two growth rates arranged i n descending order of magnitude of the instantaneous r e l a t i v e growth rate, k. . . 95 XIII. Instantaneous r e l a t i v e growth rates of high plane female deer of four r a c i a l o r i g i n s (k x 100) and (-k x 100) 97 XIV. C h a r a c t e r i s t i c s of growth patterns of i n d i v i d u a l high plane female deer of four r a c i a l o r i g i n s arranged i n des-cending order of the value of k 98 XV. The instantaneous r e l a t i v e growth rates of low plane female deer of four races, i n the f i r s t and second phase of growth 100 XVI. Size of each li n e a r element achieved at b i r t h expressed as a percentage of the asymptotic values (A) for high plane males of the Vancouver Island race . . . . . . . . . . 115 XVII. The rate of approach to mature siz e expressed by the Waiford method k* = Lt+3 ~ Lt+2 f o r f i t t e d values of L Lt+2 - Lt+1 for Vancouver Island high plane male deer 118 XVIII. The rate of decline i n growth rate of Vancouver Island high plane male deer for each linear measurement expressed as -k x 100 derived from the equation L = A - Be~ k t. . 119 XIX. Comparisons of male and female high plane Vancouver Island deer with regard to b i r t h s i z e , expressed as a percentage of f i n i t e size and mature size 125 Table ix Page XX. Comparison between males and females with regard to average rates of li n e a r growth (k*) and the average rate of decline i n growth (-k x 1 0 0 ) . . . . . . . 127 XXI. The e f f e c t of a low plane of n u t r i -tion on mature size (A) rate of decline i n growth rate (-k x 100) and rate of growth (k*) demonstrated by the males of the Vancouver Island race. . . . . . . . . . . . 134 XXII. The mean ages at which the mature size (A) of each measurement was attained for high plane males, Vancouver Island race 140 XXIII. The e f f e c t of sex and the plane of n u t r i t i o n upon the r a t i o s of certa i n l i n e a r measurements for the Vancouver Island race of deer using mature sizes (A) 145 XXIV. Progressive changes i n the chest g i r t h to hind leg length r a t i o for males of the Vancouver Island race related to increasing age on two planes of n u t r i -tion 147 XXV. Comparative growth c h a r a c t e r i s t i c s of high plane males of four races of Bl a c k - t a i l e d deer . 149 XXVI. Relative proportions of some lin e a r measurements at mature sizes (A) i n the high plane males of four races of deer. . 154 Tables i n Appendix A. Proximate composition of U.B.C. deer ra t i o n #15-56 175 B. Formulation for University of B r i t i s h Columbia deer r a t i o n . 176 C. The cause of death of a l l deer which died prior to reaching 1000 days of age 177 X Table Page D. Parameters for weight growth i n the formulation of the s e l f - a c c e l e r a t i n g equation, W = Ae^t for the e f f e c t i v e curve of growth . . . . . . . 178 E. Parameters for weight growth i n the formulation of the s e l f - i n h i b i t i n g equation, W = A - Be _ l c t for the e f f e c t i v e curve of growth. . 179 F. Parameters for l i n e a r growth i n the formulation of the equation L = A -Be-kt for a l l deer studied 180 x i LIST OF FIGURES Figure Page 1. Milk rat i o n standards 14 2. Ration 15-56 feeding standards 14 3. E f f e c t i v e curves of growth for high plane male deer, No's. 51L and 92L 25 4. A Walford graph used i n the estimation of "A" for deer No. 92L 27 5. A graphic method for the evaluation of "A" 29 6. The i n t e r s e c t i o n of s e l f - a c c e l e r a t i n g and s e l f - i n h i b i t i n g growth equations (No. 92L) 31 7. One and a half year old Sitka Black-t a i l e d deer showing the e f f e c t s of the plane of n u t r i t i o n upon body con-formation, pelage and antler develop-ment 45 8. The actual and e f f e c t i v e weight growth of a high plane male deer (No. 92L) 49 9. Basic curves of growth for high plane male deer No. 92L 53. 10. Growth patterns of high plane male and female deer 60 11. Average d a i l y food intake i n 15 day i n t e r v a l s for male and female deer 65 12. The seasonal growth of high plane males from four races of B l a c k - t a i l e d deer 67 13. A comparison of the growth curves of high and low plane male deer 71 14. The e f f e c t of a high plane diet upon early low plane growth 77 15. The r e l a t i o n s h i p between age at matur-i t y and growth rates 94 x i i Figure Page 16. The equation W = A - Be~ k t f i t t e d from the second phase data and extrapolated through the prepubertal phase of low plane deer i n 19L 102 17. The l i n e a r growth patterns of a high plane male C a l i f o r n i a n B l a c k - t a i l (OIL) , . 109 18. The l i n e a r growth patterns of a high plane male Vancouver Island Black-t a i l (50L) I l l 19. The li n e a r growth patterns of a high plane male Sitka B l a c k - t a i l (30L) 112 20. The li n e a r growth patterns of a high plane male Mule deer 113 21. A regression of the rate of decline i n growth (-k x 100) on the rate of growth (k*) for a l l six l i n e a r measurements from high plane Vancouver Island males. . . 1212 22. The linear growth patterns of a high plane female (53L) 124 23. Regressions of the rate of decline i n growth on the rate of growth for high plane females 130 24. The li n e a r growth patterns of a low plane male (58L) 133 25. A regression of the rate of decline i n growth on the rate of growth for low plane males 138 ACKNOWLEDGEMENTS T h i s s t u d y was f i n a n c e d by t h e N a t i o n a l R e s e a r c h C o u n c i l o f Canada and by t h e F i s h and Game B r a n c h o f t h e B r i t i s h C o l u m b i a D e p a r t m e n t o f R e c r e a t i o n and C o n s e r v a t i o n . S e v e r a l p e o p l e g e n e r o u s l y c o n t r i b u t e d t h e i r t i m e and t h o u g h t t o t h e s t u d y . Many i d e a s i n c o r p o r a t e d i n t o t h e p l a n n i n g and e x e c u t i o n o f t h e s t u d y a r o s e f r o m d i s c u s s i o n s w i t h D r . I . McT. Cowan, Dean o f G r a d u a t e S t u d i e s and Dr. A. J . Wood o f t h e D i v i s i o n o f A n i m a l S c i e n c e . I n a d d i t i o n , t h e y f u r n i s h e d t h e f a c i l i t i e s w i t h o u t w h i c h t h i s s t u d y w o u l d n o t have been p o s s i b l e . I am a l s o i n d e b t e d t o Dr. W. D. K i t t s o f t h e D i v i s i o n o f A n i m a l S c i e n c e and t o Dr. H. C. N o r d o n , a R e s e a r c h A s s o c i a t e , D e p a r t m e n t o f Z o o l o g y , f o r t h e i r u n d e r -s t a n d i n g and a s s i s t a n c e t h r o u g h o u t t h e s t u d y . Dr. J . H a t t e r , Mr. D. J . R o b i n s o n and many o t h e r members o f t h e B. C. F i s h and Game B r a n c h a s s i s t e d i n t h e c o l l e c t i o n o f fawns and c o n t r i b u t e d i n many ways t o w a r d s t h e s u c c e s s f u l c o m p l e t i o n o f t h e s t u d y . Dr. D. R. K l e i n , f o r m e r l y o f t h e U. S. F i s h and W i l d l i f e S e r v i c e , c o n t r i b u t e d t o w a r d s t h e s t u d y by p r o v i d i n g newborn fawns f r o m A l a s k a . S i m i l a r l y , t h a n k s a r e due t o t h e s t a f f o f t h e C a l i f o r n i a F i s h and Game D e p a r t m e n t and p a r t i c u l a r l y t o t h e s t a f f o f t h e Y o n t v i l l e Game Farm f o r t h e i r h e l p i n t h e c o l l e c t i o n o f fawns. I am a l s o i n d e b t e d t o Mr. James O' K e e f e , t o my X l V wife, Helen, and to many others who helped to feed and nurse the study animals and otherwise contributed to the study. 1 INTRODUCTION The b l a c k - t a i l e d deer (Odocoileus hemionus) i s represented by eleven races i n i t s range of d i s t r i b u t i o n throughout western North America (Cowan, 1956). These races d i f f e r from each other i n colour patterns, s k e l e t a l c h a r a c t e r i s t i c s , and i n body size and proportions of the adult. The l a t t e r are due to differences i n growth pat-terns resulted from the genetic constitution of the race, to the e f f e c t of d i f f e r e n t environments upon the expres-sion of growth.,potential and, i n some degree, upon the inte r a c t i o n of both factors. In order to determine the magnitude of differences i n the genetic pattern of growth, i t i s necessary to standardize environmental influences and to compare the re s u l t i n g growth patterns exhibited by representatives of d i f f e r e n t r a c i a l stocks. For thi s reason, newborn fawns were obtained from four widely sep-arate geographic locations and raised to maturity under s p e c i f i c environmental conditions at the University of B r i t i s h Columbia. This study i s one of a series on the biology of deer c a r r i e d out by the W i l d l i f e Research Unit of the University of B r i t i s h Columbia. Changes i n body siz e and proportions are i n f l u -enced, not only by the sum t o t a l of a l l environmental factors, but i n p a r t i c u l a r , by the n u t r i t i o n a l aspect of the environment. It has been suggested that some of the 2 differences i n size and form exhibited by separate races are due d i r e c t l y to the quality and quantity of the a v a i l -able food supply (Cowan, 1936; Einarsen, 1946; Cowan and Wood, 1955). To explore t h i s influence representatives of four races of b l a c k - t a i l e d deer were raised under control-led n u t r i t i o n a l conditions. A q u a l i t a t i v e l y suitable diet was fed at two quantitative l e v e l s ; one designed to permit a close approach to maximum growth potential and the other reduced to a l e v e l s l i g h t l y above maintenance requirements. In t h i s manner, gene t i c a l l y controlled expressions of growth can be measured at two n u t r i t i o n a l levels while other environmental conditions remain constant. Within a given race, i n d i v i d u a l variations i n size-at-age indicate that growth i s controlled by the genetic c o n s t i t u t i o n of the i n d i v i d u a l . Thus i n one set of environmental circumstances, i n d i v i d u a l variations i n growth rate, size-at-age and body form are an expression of the v a r i a b i l i t y of genotypes within the race. However, the environment can modify growth patterns to the extent that the genetic p o t e n t i a l for growth may be completely masked. The resultant form expresses the a b i l i t y of the animal to grow i n a p a r t i c u l a r set of environmental conditions but does not r e f l e c t the true genetic potential for growth. Under natural conditions, animals are seldom able to express their genetic p o t e n t i a l as the environment i s 3 u s u a l l y l e s s than o p t i m a l . Thus, mean s i z e - a t - a g e f o r one p o p u l a t i o n i s an e x p r e s s i o n o f the s u i t a b i l i t y o f the e n v i -ronment f o r growth and an e x p r e s s i o n o f the g e n e t i c a b i l i t y o f the members t o growth w i t h i n the p a r t i c u l a r environment. Form, as e x p r e s s e d by the r e l a t i o n s h i p o f l i n e a r d i m e n s i o n s , and changes i n form c o n c u r r e n t w i t h growth i n s i z e , may r e f l e c t g e n e t i c d i f f e r e n c e s between r a c e s t o a g r e a t e r degree than mass i t s e l f . A l t h o u g h form i s r e l a t e d t o mass a t any g i v e n s i z e , i t i s a d i r e c t e x p r e s s i o n o f the genotype o f the i n d i v i d u a l . F u r t h e r m o r e , the range o f v a r i a t i o n i n i n d i v i d u a l s a t s p e c i f i c s i z e s , i s t y p i c a l o f the r a c e t o wh i c h they b e l o n g . Thus e n v i r o n m e n t a l f a c t o r s , w i t h the p o s s i b l e e x c e p t i o n o f s p e c i f i c n u t r i e n t d e f i c i e n -c i e s , have l i t t l e o r no b e a r i n g on the e x p r e s s i o n o f form a t any s p e c i f i e d s i z e , e x c e p t through the l o n g - t e r m p r o c e s s e s o f e v o l u t i o n and a d a p t a t i o n . Two s t o c k s o f a g i v e n s p e c i e s w h i c h d i f f e r i n the magnitude o f a g i v e n d i m e n s i o n have f r e q u e n t l y been s e p a r -a t e d i n t o d i f f e r e n t r a c e s . However, as form i s r e l a t e d t o s i z e and s i z e under n a t u r a l c o n d i t i o n s i s r e l a t e d t o e n v i r o n m e n t a l o p p o r t u n i t y f o r growth, then such d i f f e r -ences i n form are s i g n i f i c a n t o n l y i f they a r e m a i n t a i n e d when r e p r e s e n t a t i v e s o f b o t h s t o c k s a re r a i s e d under i d e n t i c a l e n v i r o n m e n t a l c o n d i t i o n s . F u r t h e r m o r e , because form changes t h r o u g h o u t the a c t i v e growth p e r i o d , c o m p a r i -4 sons of li n e a r dimensions must be made at comparable sizes or by comparing the changes i n form between given ages within a s p e c i f i c set of environmental conditions. Brody (1921) stated, i n reference to several breeds of fowl, that the magnitude of growth parameters may afford, under given dietary conditions, a means of defining races which are as trustworthy as the i r external c h a r a c t e r i s t i c s . Changes i n form are an i n t e g r a l part of the study of growth since s i z e i s only the a n a l y t i c a l expression of the summed magnitudes of a l l parts. Some organisms attain the proportions of the adult configuration early i n l i f e while others mature slowly and i n recognizable stages (Medawar, 1945). Thus form and size characterize i n d i v i d -uals and races and are associated with evolutionary and adaptive p r i n c i p l e s as well as with genetic v a r i a b i l i t y and environmental opportunity. Studies of early growth patterns i n the Columbian B l a c k - t a i l e d deer under controlled n u t r i t i o n a l conditions from b i r t h to 135 days of age showed that there was a marked uniformity i n weights-at-age and i n early rates of growth (Cowan and Wood, 1955). This conclusion attests to the high degree of s i m i l a r i t y i n genotype which i s found i n a naturally-occurring race when placed under i d e n t i c a l environmental conditions. I t was shown, however, that during the early and very rapid growth phases, even minor 5 changes i n environmental circumstances gave r i s e to r e l a -t i v e l y major upsets i n the d e t a i l of the growth pattern. Such upsets were p a r t i a l l y compensated by more active l a t e r growth but i t was suggested that loss of physiological time i n the course of growth could not be completely regained. If t h i s i s true, then such changes i n environmental c i r -cumstances could give r i s e to animals that depart from the norm of the species even though conditions were controlled and s i m i l a r for the entire group. Since indiv i d u a l s showed an a b i l i t y to compensate, at least i n part, for periods of decreased growth, the v a r i a b i l i t y which i s c h a r a c t e r i s t i c of the species i s related not only to the opportunities for growth i n the p a r t i c u l a r micro-environment of the i n d i v i d -uals but also to the animals genetic a b i l i t y to compensate. If , however, compensatory growth can e f f e c t u a l l y regain time l o s t i n the course of growth, then only at the ultim-ate or mature size w i l l the i n d i v i d u a l r e f l e c t i t s own genotype for the p a r t i c u l a r set of environmental circum-stances. Dickerson (1954) implied that compensatory growth i s p a r t i a l l y capable of regaining l o s t growth when he sta-ted that mature size i s affected more than early growth by the i n d i v i d u a l s genotype and less by the environment. In e a r l i e r studies of the growth patterns of Columbian B l a c k - t a i l e d deer to 18 months of age, the micro-environment was sim i l a r for a l l indivi d u a l s (Bandy, 1955). Because i t was recognized that n u t r i t i o n a l intake i s the 6 most i n f l u e n t i a l e n v i r o n m e n t a l f a c t o r a s s o c i a t e d w i t h g rowth, the deer were f e d i s o c a l o r i c a l l y a d i e t w h i c h was c o n s i d e r e d c a p a b l e o f s u p p o r t i n g maximum growth. The growth p a t t e r n s o b t a i n e d from t h e s e deer i n d i c a t e d t h a t , imposed upon a s i m p l e p a t t e r n o f s i z e i n c r e a s e , t h e r e was a marked s e a s o n a l i n f l u e n c e on s i z e - g r o w t h . A r e t a r d a t i o n o f growth o c c u r r e d d u r i n g the w i n t e r w h i c h as a s s o c i a t e d w i t h a r e p r o d u c t i v e rhythm. Male deer v o l u n t a r i l y reduced t h e i r f o o d i n t a k e a t a time when they showed s i g n s o f becoming r e p r o d u c t i v e l y a c t i v e . However, changes i n form shown by the growth o f p a r t s r e l a t i v e t o the w e i g h t s o f the a n i m a l s remained c o n s t a n t . A n i m a l s on a p l a n e o f n u t r i t i o n w h i c h s e v e r e l y r e s t r i c t e d growth showed t h a t the n u t r i t i o n a l l e v e l a f f e c t e d t h e i r r e p r o d u c t i v e a c t i v i t y and t h e r e f o r e a l s o m o d i f i e d the e f f e c t o f r e p r o d u c t i v e a c t i v i t y on growth. However, i t was apparent t h a t a s e a s o n a l growth rhythm e x i s t e d w h i c h c o m p l i c a t e d the p a t t e r n o f s i m p l e s i z e i n c r e a s e . As a r e s u l t , t h e r e a r e a l t e r n a t i v e methods o f d e p i c t i n g t h e c o u r s e o f growth. F i r s t of a l l , because the r e p r o d u c t i v e o r s e a s o n a l e f f e c t on growth i s an i n t e g r a l p a r t of t h e b i o l o g y o f the a n i m a l s , such changes s h o u l d be i n c l u d e d i n any s t u d y o f growth. S e c o n d l y , the e f f e c t s o f r e p r o d u c t i v e a c t i v i t y on growth c o u l d be c o n s i d e r e d as i m m a t e r i a l t o the b a s i c c o u r s e of growth and c o u l d t h e r e -f o r e be d i s r e g a r d e d f o r a n a l y t i c a l p u r poses. The s t u d y o f growth i n v o l v e s the d e s c r i p t i o n o f 7 changes i n s i z e and shape i n r e l a t i o n t o age. V e r b a l des-c r i p t i o n s o f such changes a r e u n w i e l d y and do n o t l e n d t h e m s e l v e s t o a n a l y s i s w i t h the same f a c i l i t y as do r e p -r e s e n t a t i v e numbers. For t h i s r e a s o n , i t i s customary t o e x p r e s s growth i n n u m e r i c a l r e l a t i o n s h i p w i t h time. B o t h s i z e and age a r e d i r e c t l y m e asurable and t h e i r a n a l y s i s i s governed by o r d i n a r y m a t h e m a t i c a l methods. Shape, on the o t h e r hand, does n o t l e n d i t s e l f t o s i m p l e m a t h e m a t i c a l e x p r e s s i o n , b u t a n a l y s i s can be made through t h e s t u d y of r e l a t i v e changes w i t h i n p a r t s o f the whole organism. I t i s o n l y n e c e s s a r y t o ensure t h a t the measured v a l u e s a r e t r u l y r e p r e s e n t a t i v e o f the shape o f the a n i m a l and t o r e c o g n i z e t h a t t h e e n t i r e shape i s n o t d i v i s i b l e i n t o p o r t i o n s which can be r e p r e s e n t e d by s i m p l e numbers. N e v e r t h e l e s s such a n a l y s i s can d e p i c t c e r t a i n changes i n the shape of an i n d i v i d u a l w i t h i n c r e a s i n g age. Once growth d a t a have been c o l l e c t e d t h e r e are t h r e e g e n e r a l a n a l y t i c a l p l a n s w h i c h c o u l d be f o l l o w e d . F i r s t o f a l l , the c o u r s e o f growth c o u l d be a n a l y s e d w i t h r e s p e c t t o each change and i n f l e c t i o n . T h i s t r e a t m e n t i s v a l u a b l e over r e l a t i v e l y s h o r t time p e r i o d s i n t h e a s s e s s -ment of d i u r n a l rhythms and the e f f e c t s o f s i n g l e f a c t o r s such as a s p e c i f i c c h e m i c a l on the c o u r s e o f growth. However, the g e n e r a l growth p a t t e r n , i f t r e a t e d by t h e a n a l y s i s o f minute d e t a i l , i s m a t h e m a t i c a l l y cumbersome and i s u n l i k e l y t o l e a d t o g e n e r a l i z a t i o n s c o n c e r n i n g the 8 growth p r o c e s s . I n a d d i t i o n , e x t r e m e l y a c c u r a t e measure-ments o f s i z e a r e n e c e s s a r y i n o r d e r t o d e p i c t t r u e changes and d i f f e r e n c e s i n the c o u r s e o f growth so t h a t t h e s e a r e n o t c o n f u s e d w i t h e x p e r i m e n t a l e r r o r . The second approach t o the a n a l y s i s o f growth i s based on the a ssumption t h a t r e l a t i v e l y s m a l l changes i n w e i g h t s , w i t h i n a g i v e n s e r i e s , a r e a l l the p r o d u c t o f e x p e r i m e n t a l e r r o r . A l t h o u g h such an assumption may be p a r t l y f a l s e , the c o u r s e o f growth may be d e p i c t e d as a smooth c o n t i n u o u s c u r v e o r a s e r i e s o f c u r v e s . I n t h i s a pproach, however, major d e v i a t i o n s i n growth must be t r e a t e d as i n t e g r a l p a r t o f the t r u e c o u r s e of growth and must t h e r e f o r e be r e d u c e d t o m a t h e m a t i c a l terms w h i c h are c a p a b l e o f b e i n g a n a l y s e d . T h i s method would t h e r e f o r e i n c o r p o r a t e s e a s o n a l rhythms and the e f f e c t o f r e p r o d u c -t i v e p e r i o d s on the c o u r s e o f growth. The t h i r d and l a s t g e n e r a l approach t o the a n a l y s i s o f growth i s an e x t e n s i o n o f the second. I n t h i s approach i t i s assumed t h a t a n i m a l s s t e a d i l y c o n t i n u e t o grow;;towards a mature s i z e and t h a t any d e v i a t i o n s from the c o u r s e a r e i m m a t e r i a l t o the e f f e c t i v e p a t t e r n o f s i z e i n c r e a s e . Curves r e p r e s e n t i n g s e a s o n a l and r e p r o d u c t i v e changes i n the c o u r s e o f growth are c o n s i d e r e d t o be imposed upon a b a s i c growth p a t t e r n and must t h e r e f o r e be t r e a t e d s e p a r a t e l y . 9 Each o f t h e s e t h r e e approaches t o t h e t r e a t m e n t of growth d a t a i s u s e f u l f o r v a r i o u s t y p e s o f a n a l y s i s and each may g i v e r i s e t o g e n e r a l i z a t i o n s about growth which are u s e f u l . The p r o c e s s e s of growth are i n t i m a t e l y bound t o the p r o c e s s e s o f m e t a b o l i s m , t o the environment, t o hormonal r e g u l a t i o n and t o t h e g e n e t i c o r g a n i z a t i o n o f the growth p a t t e r n . Each o f the t h r e e approaches emphasizes d i f f e r e n t a s p e c t s of t h e growth p i c t u r e and i s n o t e x c l u -s i v e . I n the s t u d y o f growth p a t t e r n s i n f o u r r a c e s o f b l a c k - t a i l e d deer b o t h the second and t h i r d approaches t o the a n a l y s i s o f growth have been used. The f i r s t approach i s n o t c o n s i d e r e d u s e f u l f o r t h i s s t u d y because t h e r e i s no method of e v a l u a t i n g e r r o r s o f measurements. Hence, t r u e but s m a l l p e r i o d i c f l u c t u a t i o n s i n growth a r e o b s c u r e d by t h e s e e r r o r s . 10 MATERIALS AND METHODS EXPERIMENTAL ANIMALS AND THEIR CARE Columbian B l a c k - t a i l e d deer, (Odocoileus hemionus  columbianus) were co l l e c t e d as fawns between approximate ages of three to f i f t e e n days from coastal C a l i f o r n i a and Vancouver Island i n 1956. Mule deer fawns (0. h. hemionus) and Sitka deer (0. h^ sitkensis) were s i m i l a r l y c o l l e c t e d i n the southern i n t e r i o r of B r i t i s h Columbia and near Petersburg i n the Alaskan panhandle, respectively. On cap-ture, a l l fawns were weighed, measured, and marked for i d e n t i f i c a t i o n . They were fed evaporated milk d i l u t e d to 50% with water while being held for shipment to the U. B. C. Research Farm on Vancouver Island. Milk intake and weight changes were recorded during the period prior to shipment. Upon receipt, each fawn was ear-tattooed for i d e n t i f i c a t i o n and then placed i n plywood rearing pens of 4' x 4' x 4'. These pens were situated on an asphalt f l o o r within a barn and the fawns remained i n these pens, except during exercise periods, u n t i l the f a l l of 1956. In early October, the fawns were moved into semi-open pens si m i l a r i n design to those described by Wood, ejt _al. (1961). They remained i n these pens u n t i l they were f i n a l l y moved to the experimental pens at the University of B r i t i s h Columbia i n September of 1957. 11 Evaporated milk was fed to the fawns by bottle i n four equal portions per day, from the time of their a r r i v a l at the Research Farm u n t i l they were weaned. Evaporated milk was found to be a sa t i s f a c t o r y substitute for does' milk because i t s composition i s sim i l a r i n terms of t o t a l s o l i d s and protein content when fed i n an undiluted condi-tion (see K i t t s , et a l . 1956 and Wood, et a l . 1961)'. The milk was supplemented by the addition of 0.13 gms of f e r r i c c i t r a t e , 0.50 gms of magnesium chloride and 6.0 mgms of anhydrous copper sulphate per l i t e r of milk. This supple-ment was included i n order to stimulate hemopoiesis and maintain a high blood hemoglobin l e v e l . During the suckling period the fawns were fed i s o c a l o r i c a l l y at a l e v e l below the i r calculated capacity i n order to promote i n t e r e s t i n eating s o l i d food. Small amounts of U. B. C. Deer Ration #15-56 (see Appendix, Tables A and B) and freshly cut grass were available to the fawns at a l l times from the date of their a r r i v a l at the experimental unit. In addition, a block of cobalt-iodized s a l t was placed i n each pen. The e a r l i e s t a r r i v a l s , the C a l i f o r n i a deer, were randomly divided into high and low plane groups and were fed i s o c a l o r i c a l l y according to calculated schedules. I t was soon found that high plane fawns were incapable of con-suming the high plane milk rat i o n when fed four times per 12 day. For t h i s reason, and because i t was considered neces-sary to wean the fawns as early as possible, a l l fawns were then fed according to the low plane schedule. The agitated behaviour and continuous feeding c r i e s of the fawns in d i c a -ted that t h i s plane was too low. As a r e s u l t , the low plane schedule was increased by three ounces of milk throughout the curve. This standard was therefore used for the b a l -ance of the suckling period of the C a l i f o r n i a deer and for the entire suckling period of the three other races. The re l a t i o n s h i p of the plane of n u t r i t i o n used and the high and low calculated planes are shown i n F i g . 1. Weaning was accomplished on a semi-voluntary basis as a r e s u l t of experience gained i n previous studies (Bandy, 1955). Daily weighings of the unconsumed rati o n #15-56 permitted observation of the i n i t i a l i n t e r e s t i n s o l i d food. A l l races, except the Mule deer, showed i n i t i a l i n t e r e s t at approximately 12 lbs body weight while the average weight of the Mule deer was 15 lbs. Once i t was observed that an animal was consuming rati o n #15-56, the milk portion of the rat i o n was reduced to three-quarters of the calculated d a i l y r a t i o n . This measure stimulated fur-ther i n t e r e s t i n s o l i d food and the milk rat i o n was then gradually decreased over an average period of 26 days. The fawns were thus weaned at an average age of 56 days and an average weight of 17.3 lbs. Subsequently, fawns have been fed at a higher l e v e l and found to wean at weights of 12 to 13 14 lbs (Woods, et a l . 1961). Immediately after weaning, the animals i n each race and sex were randomly divided into two groups. The high plane group was fed at a l e v e l calculated to produce rates of growth which approached maximum, while the low plane group was fed at a c a l o r i c : l e v e l of 50% of the high plane standard. However, due to the poor physical condi-ti o n of the low plane group, i t was found necessary during the winter to increase the da i l y r a t i o n above the c a l c u l a -ted schedule. Thus the e f f e c t i v e plane of n u t r i t i o n for the low plane group was somewhat higher than shown by the low plane schedule for the feeding of ration #15-56 i n F i g . 2. PLANES OF NUTRITION Computations of the milk feeding standards were based on the proximate composition of evaporated milk. Evaporated milk i s reported to contain 7.0 gms of protein, 9.9 gms of carbohydrate and 7.9 gms of f a t per 100 gms of milk, (Hawk, et a l . 1951, p. 1238). These values were then converted to c a l o r i e s by using the factors 4, 4 and 9 which represent approximations of the metabolizable energy per gram of protein, carbohydrate and f a t respectively (Brody, 1945). It was thus determined that evaporated milk con-tained 40 c a l o r i e s of metabolizable energy per ounce. Subsequent analysis and bomb calorimeter evaluation showed 14 1 1 1 1 ' 1 1 5 10 15 20 25 30 Body Weight in lbs. 8 i - Fig. 2. Ration 15-56 feeding standards. ~» 6 -(A £ C o o ^ >% o ° 2 -40 80 120 160 200 240 Body Weight in lbs. 15 that the gross energy value of the milk was 43.5 cal/oz (O'Keefe, 1957). Since l i t t l e of the milk s o l i d i s l o s t as gas or i n urine, metabolizable energy may be considered equivalent to d i g e s t i b l e energy. As O'Keefe found the aver-age d i g e s t i b i l i t y of the milk rat i o n to be 90%, the d i g e s t i -ble portion i s represented by 39.15 ca l o r i e s per ounce. Thus, the estimation of 40 cal/oz for the metabolizable energy f r a c t i o n was considered a close approximation, suitable for the computation of the dail y food allowance. The da i l y milk rat i o n for maximum growth was com-puted on the premise that resting metabolism i n young growing deer i s energetically equivalent to 70.5 x wO-67 ca l o r i e s , where 70.5 represents the c a l o r i c requirement per unit weight and W represents body mass i n kilograms. The exponent 0.67, was selected as a re s u l t of previous studies (Bandy, 1955) and because i t was reported that the value of the exponent was found to be i n the order of 2/3 for young growing goats (Brody, 1945). The high plane milk ration was also based on the premise that maximum food energy consumption i s approximately f i v e times the basal l e v e l (Kleiber, 1933). The high plane feeding standard may therefore be represented by the equation: Max. da i l y food allowance (oz) = 70.5 x W x_5 40 where the metabolizable energy value of the milk i s 40 ca l o r i e s per f l u i d ounce. It was recognized that feeding 16 at t h i s l e v e l would r e s u l t i n large fluctuations i n accept-ance and for t h i s reason, the calculated high plane standard was reduced from the above by 10%. The low plane feeding standard for the milk rati o n was computed at 50% of the high plane l e v e l . How-ever, as noted previously, a l l fawns were eventually fed according to the low plane standard, to which was added three ounces per day. The resultant plane of n u t r i t i o n used during the suckling period was therefore a moderate l e v e l of approximately 65% of the calculated high plane, which i s lower than the l e v e l recommended by Wood, et a l . (1961), (see F i g . 1). The feeding standard for rat i o n #15-56 was c a l -culated i n a s i m i l a r manner to that used for the milk rat i o n . Protein, f a t and carbohydrate values of the r a t i o n were computed from the composition of the r a t i o n and the proximate analysis of i t s constituents as suggested by Morrison (1956). It was estimated that 100 gms of U, B. C. rati o n #15-56 contained 15.4 gms of protein, 4.0 gms of f a t and 56.6 gms of carbohydrates. These estimated values are s l i g h t l y lower than those found by chemical analysis (O'Keefe, 1957, see Appendix, Table A). The energy value of the rat i o n was then computed by the 4-4-9 conversion values suggested by Brody (1945) as representative of the metabolizable energy values per gram 17 of protein, carbohydrate and f a t respectively. These c a l -culations revealed a metabolizable energy value of 1250 c a l o r i e s per pound of ration #15-T56. Since such c a l c u l a -tions are based on estimates, the value was rounded to 1200 c a l / l b of food, for use i n further computation. Bomb calorimeter analysis of the rati o n subse-quently proved that the gross energy of the rat i o n , as fed, was 1850 c a l o r i e s per pound. Digestion t r i a l s showed that the d i g e s t i b l e portion of the rati o n varied i n d i f f e r e n t tests from 62% to 77% with an average of 70% (G'Keefe, 1957). Thus, the d i g e s t i b l e portion was represented by 1295 c a l o r i e s per pound. Energy loss through fermentation gases and i n the urine would further reduce t h i s value i n terms of metabolizable energy. Thus the approximation of 1200 c a l / l b was considered adequate for the establishment of feeding standards. The high and low plane standards of food allow-ance for rati o n #15-56 were calculated i n e s s e n t i a l l y the same manner as for the milk ra t i o n . However, i t was assumed that the value for basal energy requirements of adult animals was applicable throughout the post-weaning period. Thus the basal energy requirement was assumed to 0 7*3 be 70.5 x W • c a l o r i e s per day throughout the entire growth period following weaning. The exponent 0.73 was obtained from Brody's analysis of basal metabolism and 18 weight for various species of mature animals. Since experi-ence has shown that an animal can seldom i f ever use the the o r e t i c a l maximum energy intake, the high plane standard was reduced by 10% from the calculated maximum food intake l e v e l . The calculated d a i l y food allowance was therefore based on the formula: Daily food allowance — 70.5 x W0-73 x 5 x 9 0 lbs/day 1200 x 100 The low plane standard was computed i n the same manner and was reduced by 50% (Fig. 2). The calculated d a i l y r a t i o n was placed i n the pens each day and any remaining food was weighed on the f o l -lowing morning. In t h i s way a complete record of ingested food was obtained. BODY WEIGHTS AND MEASUREMENTS During the early phase of growth, deer were weighed on a platform scale every second day so that da i l y food allowances could be advanced as weight increased. At la t e r growth stages the i n t e r v a l s between weighings were lengthened. Weights were measured to the nearest h a l f -pound with an accuracy of + 1/2 pound. Several body measurements were also made on a l l deer throughout the experiment. Height-at-withers was measured as the v e r t i c a l distance from the ground to the 19 back-bone along the front leg. Since deer are capable of large v e r t i c a l movements of the body at the shoulders, t h i s measurement was taken when the animals were considered to be extended. The hind leg was measured with a s t e e l tape from the t i p of the toe to the proximal t i p of the calcan-eous bone. Chest g i r t h was measured immediately behind the shoulders and the measurement was read at the smallest circumference found during the breathing movements of the chest. Width at the hips was measured with c a l i p e r s from outer edges of the hips at the crest of the ileum. Head length was measured i n a median position, with a s t e e l tape, from the laboidal crest to the h a i r l i n e of the nose. Head width was measured from the posterior corner of the eye over the c r a n i a l dome to a similar point on the other side. A l l measurements were made i n centimeters to the nearest tenth. The average measurement error derived from duplicate measurements showed that the height-at-withers measurement was the least accurate with an average error of 1.41 cms. Average measurement errors for the remaining measurements were found to be as follows: chest g i r t h 0.33, hind leg length 0.38, head length 0.59, head width 0.32, and hip width 0.13 cms. ANALYTICAL METHODS FOR GROWTH IN BODY WEIGHT P e r i o d i c a l l y measured body weights were used to depict the course of growth with time for each experimental 2 0 deer. This treatment produced growth patterns which f l u c -tuated between rapid and retarded seasonal growth. As a re s u l t , the entir e weight growth curve for each animal could only be described mathematically with a polynomial equation. Because of d i f f i c u l t i e s i n the inter p r e t a t i o n of such polynomials, i t was found necessary to adapt simpler equations to parts of the curves for descriptive and compar-ative purposes. Periods of rapid summer growth were found to f i t the equation developed by Brody (1945) f o r the s e l f -accelerating phase of growth, W = Ae k* where W represents body mass at time t, A i s an integration constant and k i s the instantaneous r e l a t i v e growth rate. The data for p e r i -ods of rapid summer growth were therefore f i t t e d to th i s equation by the method of least squares (Snedecor, 1946). Seasonal peak weights and the growth pattern from b i r t h to early f a l l were noted to form a sigmoid curve si m i l a r to many c l a s s i c examples. Because the curve reached an asymptote the entir e curve of maximum values may be con-sidered as the e f f e c t i v e curve of growth r e l a t i v e to mature si z e . For t h i s reason t h i s curve w i l l be refered to as the e f f e c t i v e growth curve. The sigmoid curve of e f f e c t i v e growth for a l l ind i v i d u a l s i n f l e c t e d i n the f i r s t summer. The two equa-tions developed by Brody (1945) W = A e k t and W = A - B e - k t 21 (where W represents body mass at time t., A i s the asymptotic weight, Be i s an integration constant and -k i s the instan-taneous r e l a t i v e rate of decline i n growth) were found to f i t the pre- and p o s t - i n f l e c t i o n portions of the growth curve. As these equations resulted i n the establishment of growth parameters suitable for comparative purposes, they were used to describe the course of e f f e c t i v e growth. The data were therefore f i t t e d to these two equations by the method of least squares. In order to use d i f f e r e n t equations for the two portions of the curve, as established by Brody (1945), i t i s necessary to determine the point of i n f l e c t i o n where the " s e l f - a c c e l e r a t i n g " and " s e l f - i n h i b i t i n g " phases end and begin. There are two mathematical methods and one graphi-c a l method which might be used to determine t h i s point. The f i r s t mathematical method involves f i t t e d a curve of the form W = A e k t to early parts of the data by s t a t i s t i -c a l means. If more and more of the extenuated curve are included i n the calculations the c o e f f i c i e n t of c o r r e l a -tion w i l l eventually be reduced and the error of estimate increased. In t h i s manner a point of deviation from the exponential curve may be found. However, i n the use of t h i s technique, i t must be assumed that the c o e f f i c i e n t of co r r e l a t i o n for each c a l c u l a t i o n w i l l r e f l e c t differences i n curvature and not only differences a t t r i b u t a b l e to the experimental error or to random fluctuations. It i s 22 recognized that such a refinement i s not suitable for the data obtained i n these experiments. The second mathematical method involves the c a l -culations of absolute gains over r e l a t i v e l y short and constant periods of time. The point of i n f l e c t i o n w i l l be marked by a change from increasing gains to decreasing gains. Table I shows the absolute gains for two high plane bucks on 10, 20, and 40 day i n t e r v a l s . For deer No. 92, the increments appear to reach a maximum of 10.5 lbs in 10 days, aft e r which there i s a r e l a t i v e l y consistent decrease i n gains. Lumping the gains into 20 and 40 day periods further i l l u s t r a t e s that the point of i n f l e c t i o n was reached between certain l i m i t s of age. Since i t appears that the period of maximum gains occurs between 112 and 122 days of age, the mid-point 117 days, i s selected as representing the point of i n f l e c t i o n . The data for deer No. 51 shows s i m i l a r l y that the i n f l e c t i o n point was reached between 122 days and 162 days of age on the basis of 40 day i n t e r v a l s . Twenty-day gains indicate that the point of i n f l e c t i o n l i e s between 122 and 142 days, and the 10 day gains indicate i t s position between 132 and' 142 days of age. Thus the i n f l e c t i o n point i s again considered as the mid-point of the range, 137 days. Graphically, an approximation of the point of i n f l e c t i o n may be made by p l o t t i n g the e f f e c t i v e growth Table I . Absolute gains in 10 to 40 day periods for two high plane bucks (No. 92, Mule deer, and No. 51, Columbian Black-tail). Mule Deer Buck, No. 92 Columbian Buck, No. 51 Age-Range For Period of Gain (days of age) Absolute Gain Per 10 days (lbs) Absolute Gain Per 20 days (lbs) Absolute Gain Per 40 days (lbs) Age Range For Period of Gain (days of age) Absolute Gain Per 10 days (lbs) Absolute Gain Per 20 days (lbs) Absolute Gain Per 40 days (lbs) 22 - 32 2.0 4.0 11.0 2 - 1 2 2.8 4.3 8.8 32 - 42 2.0 12 - 22 1.5 4 2 - 52 3.0 7.0 22 - 32 2.5 4.5 52 - 62 4.0 32 - 42 2.0 62 - 72 9.0 18.0 31.5 42 - 52 1.0 3.0 9.5 72 - 82 9.0 52 - 62 2.0 82 - 92 6.0 13.5 62 - 72 2.5 6.5 92 - 102 7.5 72 - 82 4.0 102 - 112 9.5 19.5 31.5 82 - 92 5.0 6.5 13.5 112 - 122 10.5 92 - 102 1.5 122 - 132 6.0 12.0 102 - 112 3.0 7.0 132 - 142 6.0 112 - 122 4.0 142 - 152 11.0 14.0 23.0 122 - 132 4.5 10.5 18.5 152 - 162 3.0 132 - 142 6.0 162 - 172 6.0 9.0 142 - 152 3.5 8.5 172 - 182 3.0 152 - 162 5.0 182 - 192 0.0 -5.0 162 - 172 0.5 2.0 6.5 192 - 202 -5.0 172 - 182 1.5 182 - 192 2.0 4.5 192 - 202 2.5 24 curve on semilog paper. If an equation of the type used by Brody, W = Ae k t, f i t s the data, a str a i g h t l i n e should r e s u l t by p l o t t i n g weight and age on semilog paper. If such a l i n e i s produced, the point of consistant deviations of the actual observations from the straight l i n e can be selected-by inspection. F i g . 3 shows that by t h i s method the point of i n f l e c t i o n can be assessed at 120 days and 125 days for deer numbers 92 and 51 respectively. These f i g -ures agree c l o s e l y with those found by using units of gain. The graphic method may be improved by using s t a t i s t i c a l methods to f i t the straight l i n e , but such refinement can-not pin-point the i n f l e c t i o n with a high degree of accuracy because weighings were made at approximately one week in t e r v a l s during t h i s period of growth. I t i s s u f f i c i e n t for the present purpose, only to know the approximate position of the point of i n f l e c t i o n , so that data i n t h i s region may be omitted from consideration with respect to the formulation of both the accelerating and decelerating equations. The equations for the s e l f - a c c e l e r a t i n g portions of the curves for No. 92 and No. 51 are shown on Fi g . 3.* The c o e f f i c i e n t s of c o r r e l a t i o n were found to be 6.99186 and 0.98873 respectively, thereby in d i c a t i n g strong posi-t i v e correlations, which i n turn suggest that the mathem-a t i c a l treatment i s adequate. Furthermore, the use of • A l l equations shown were computed by the method of least squares (Snedecor, 1946). 200 ' 400 ' 600 ' 800 ' 1000 1200 ' 1400 1600 A G F IN DAYS 2 6 natural logarithms, as i n the equation increases the value of the c o r r e l a t i o n c o e f f i c i e n t calculated from simple a r i t h -metic regression thereby in d i c a t i n g that the use of the formula W = A e k t i s s a t i s f a c t o r y for the description of the f i r s t phase of growth. In the treatment of the self-decelerating phase of e f f e c t i v e growth, Brody suggests that growth i s no longer proportional to the mass of the growing organism, but that growth i s proportional to weight-yet-to-be made. Hence, he suggests the use of an equation represented by W = A - Be~ k t where A represents the asymptotic weight, -k i s the rate of decreasing gains, B i s an integration constant and t repre-sents age. Brody provides a graphic method for the estima-tion of k by the use of t r i a l values of A on a plo t of A -W versus age. A f i r s t approximation of the value of A may be determined by the use of a Walford (1946) graph, as shown i n F i g . 4 (See also, Beaverton and Holt, 1957 and Ricker, 1958). Since only the e f f e c t i v e growth curve i s considered, the seasonal maximum values of weight can be used and for t h i s reason, only a few observations are a v a i l -able for the estimation of A and for the evaluation of k. Fig. 4 indicates that A may have a value i n the order of 343 lbs. This value was then used on a plot of A - W to determine i f a straight l i n e was produced for the evaluation 28 of k, as shown i n Fig. 5. Correlation c o e f f i c i e n t s were calculated for the regression of In (A - W) versus age wherein A was a t t r i b u -ted the values of 343 lbs and 350 lbs. The c o e f f i c i e n t s of co r r e l a t i o n were found to be 0.99995 and 0.99867, thereby in d i c a t i n g that the Walford method i s suitable for the sele c t i o n of A. By using the Walford method, a measure of standardization i s introduced which would not r e s u l t from pure t r i a l and error estimation. Substitution of thi s value i n the formula W = A - Be~ k t for deer No. 92 re s u l t s i n the equation In (A - W) = 5.78010 - 0.001919t or W = 343 - 324e -0.001919t. The values of A and -k are useful for comparative purposes with respect to the e f f e c t i v e course of growth and may be used to characterize an i n d i -viduals genotype within a given environment. The method used here for f i t t i n g maximum seasonal weights to the equation W = A - B e - k t d i f f e r s s l i g h t l y from the method recommended by Wood, et a l . (1962). In ca l c u l a -ting the curve of maximum weight growth, they purposely omitted the maximum weight which occurred at the end of the f i r s t period of rapid growth because they considered that i n terms of body composition, the animal d i f f e r e d at t h i s 30 point from a l l subsequent peaks (Pers. Comm.). In the present study, however, the f i r s t peak value was included i n the c a l c u l a t i o n s because no f a c t u a l information was a v a i l -able to confirm the suspected difference i n body composi-tio n . Consequently i t seemed appropriate to u t i l i z e a l l peak values i n the mathematical description of the d e c e l e r -ating phase of e f f e c t i v e growth. With the establishment of equations for the s e l f -accelerating and the decelerating phase i t i s possible to e s t a b l i s h the point where these two l i n e s i n t e rsect. F i g . 6 shows that for deer No. 92, the i n t e r s e c t i o n occurs at 123 days of age or approximatly 87 lbs. Thus the i n t e r -section occurs only 5 days l a t e r than the estimated i n f l e c t i o n point by the gains method. Similar tests with other animals indicate that the interception of the two calculated curves, (W = A e k t and W = A - B e - k t ) l i e s very close to the i n f l e c t i o n point estimated by inspection of the magnitude of growth increments. Thus, the l i n e i n t e r -cept method can be used with equal f a c i l i t y for depicting a point of i n f l e c t i o n , p a r t i c u l a r l y since the periods between weighings do not permit further refinement of the estimate. Furthermore, i t i s evident that a mathematical point of i n f l e c t i o n denotes a region of r e l a t i v e l y b r i e f duration and not a f i n i t e point to which a b i o l o g i c a l explanation can be given. The i n f l e c t i o n point may, however, be used to characterize the growth pattern of an i n d i v i d u a l or race 200 • • i « • i i i i — 100 120 140 160 180 Age in days Fig. 6. The intersection of self-accelerating and self-inhibiting growth equations. (No.92L) w 32 and for th i s reason, a standard approach to i t s estimation by the l i n e intercept method may prove useful. The parameters derived from f i t t i n g the data to the two growth equations were used to compare races, sexes and the planes of n u t r i t i o n . Small numbers of animals within each group limited the use of s t a t i s t i c a l group com-parisons. Therefore, comparisons were made on representa-tive i n d i v i d u a l s and between small groups with no attempt being made to evaluate s t a t i s t i c a l l y , differences i n growth parameters. Ch a r a c t e r i s t i c s which were attr i b u t a b l e to sin g l e animals and not to the group as a whole, were omitted from consideration. This approach precluded the p o s s i b i l i t y of a t t r i b u t i n g to a genetic o r i g i n e f f e c t s which were actually the r e s u l t of i n d i v i d u a l differences i n the micro-environment for growth. ANALYTICAL METHODS FOR LINEAR MEASUREMENTS The data for each measurement were f i t t e d to the equation L = A - Be" k t where L represents a li n e a r dimension at any time " t " , A i s a constant which represents the asymptotic value, B i s an integration constant, and -k represents the rate of decline i n growth rate. An attempt was made to use the method for determining the value of A suggested by Brody (1945). T r i a l values of A were i n t r o -duced into a computer program for Triangular Multiple Regression and co r r e l a t i o n ( T r i Reg II) designed by Dr. 33 J. R. H. Dempster for use i n the IBM 1620 Computer. From a series of four t r i a l values of A, the most suitable was selected on the basis of the value of the computed multiple c o r r e l a t i o n c o e f f i c i e n t , (RSQ). This method of selection was based upOn the requirement that when the most suitable value of A i s found i n a plot of (A - L) versus age, a straight l i n e w i l l be prbduced. The assumption was made that RSQ would decrease i f a curvature resulted instead of a straight l i n e . Having determined the most s a t i s f a c t o r y value of A from the f i r s t four t r i a l values, four more t r i a l values on either side of th i s value were tested. Table II shows that two t r i a l values of A resulted i n the same RSQ thereby making i t impossible to select the most suitable value of A for the height^at-withers regression for Deer #51. Table II. Values of the multiple c o r r e l a t i o n c o e f f i c i e n t (RSQ) determined for t r i a l values of A i n the equation L = A - Be~ k t. ^_ T r i a l Values of A RSQ T r i a l Values of A RSQ 84.8 .803 96 .977 86 .949 98 .974 88 .977 100 .971 90 .982 102 .968 92 .982 104 .965 94 .979 114 .954 These r e s u l t s indicate that the multiple c o r r e l -ation c o e f f i c i e n t was too i n s e n s i t i v e for the intended purpose. In other regressions no suitable values of RSQ 34 were apparent and i n some eases, the indicated value of A appeared to be unreasonably high when compared to the graphed data. Furthermore, i t was noted that the values of -k derived from t h i s method were too low, with the re s u l t that f i t t e d curves systematically crossed the observed data at two places. This indicated that the method did not produce the necessary degree of curvature to f i t the observed data. A successful method for f i t t i n g the equation L = A - Be~ k t was developed by introducing t r i a l values of k into the equation L = A - Be"^*' + C t e ~ k t . Interpolations between the t r i a l k values were made so that the value of C approached zero. At thi s point the most suitable values of both A and k were determined simultaneously. The resultant f i t of the equations to the observed data was found to be sa t i s f a c t o r y as indicated by high values of the multiple c o r r e l a t i o n c o e f f i c i e n t and low standard errors of estimate (SY^). The shape of the curves and the excellent f i t of the equation L = A - B e _ k ^ for lin e a r measurements of growth are re a d i l y apparent i n Figs. 17 to 20 (In the d i s -cussion) . High values of the multiple c o r r e l a t i o n c o e f f i c i e n t s for high plane males, high plane females and low plane males of the Vancouver Island race i n Table III further indicate that the equation i s suitable for purposes of comparison. 35 Table I I I . The standard errors of estimates (SYk) and multi-ple c o r r e l a t i o n c o e f f i c i e n t s (Rk 2) of linear measurements, sexes and planes of n u t r i t i o n for the Vancouver Island race. Sex & Plane Sta-t i s t i c (N) Ht. @ W. Chest HL Hd.L. Hd.W. W. HP<? SY k (5) 1.538 2.606 .611 .654 .880 .419 HP? SY k (3) 1.309 2.843 .614 .621 .786 .465 LPc? SY k (2) 1.6 83 1.114 .707 .422 .587 .314 HP<r Rk 2 (5) .991 .979 .992 .977 .919 .985 HP? R k 2 (3) .990 .979 .986 .977 .902 .980 LPs' Rk 2 (2) .980 .991 .985 .985 .939 .983 Ht. @ W. = Height-at-withers; Chest = Chest g i r t h ; HL = Hind leg length; Hd.L. = Head length; Hd.W. = Head width; Hip W. = Hip width. The standard errors of estimate i n the same table denote differences between measurements with regard to the magnitude of errors associated with the f i t t e d equation. Chest g i r t h i s associated with the highest standard errors in the curves representing high plane males and females. This i s thought to be due to r e l a t i v e l y large errors of measurement and to the r e l a t i v e l y poor f i t of the curves through that portion of the curve associated with the winter period of growth cessation. The low standard error shown for low plane males i s probably d i r e c t l y attributable to the lack of a growth cessation period. Height-at-withers regressions are associated with the second highest standard errors of estimates, followed 36 by the head width measurement. Both of these measurements were d i f f i c u l t to obtain accurately. The r e l a t i v e l y high error for the low plane males i s thought to be related to increased d i f f i c u l t i e s of measurement associated with the behaviour of thi s group. Low plane deer tended to crouch when approached so that i t was d i f f i c u l t to obtain their maximum height. The s i m i l a r i t i e s i n multiple c o r r e l a t i o n coef-f i c i e n t s and low standard errors of estimates indicate that the equation L = A - Be~ k t provides a suitable f i t for a l l regressions. As a r e s u l t , differences i n the comparison of derived regression c o e f f i c i e n t s and constants may be a t t r i b u -ted to r e a l differences rather than to alte r a t i o n s due to the degree of f i t and magnitude of errors. 37 RESULTS THE EXPERIMENTAL DEER HERD A t o t a l of 66 deer fawns were received at the University of B r i t i s h Columbia Research Farm at Oyster River, Vancouver Island. Twenty Columbian B l a c k - t a i l fawns from northern C a l i f o r n i a , 9 Sitka deer from Juneau and Mitkof Island, Alaska, and 21 Mule deer fawns from various places i n the southern i n t e r i o r of B r i t i s h Columbia were flown to the Research Farm shortly after capture. Sixteen Columbian B l a c k - t a i l e d deer fawns were also obtained from the Courtenay-Campbell River area of Vancouver Island and were transported immediately after capture to the Research Farm. The estimated age of the fawns at capture ranged from one to twenty-eight days post-partum with an average age of 7.4 days. Table IV shows the d i s t r i b u t i o n of numbers of deer with regard to sex and the plane of n u t r i t i o n on which each animal was placed. Eleven fawns died shortly after receipt and before they were committed to one of the estab-li s h e d planes of n u t r i t i o n . Of the remainder, 33 were males and 22 were females. A l l fawns quickly learned to drink from a baby b o t t l e with the r e s u l t that gains i n body weight were recorded almost immediately after s t a r t i n g the a r t i f i c i a l 38 feeding program. Only one fawn died as a r e s u l t of the treatment received i n placing them on an a r t i f i c i a l diet. A l l attempts to teach th i s fawn to suckle from a bottle f a i l e d . Table IV. The d i s t r i b u t i o n of experimental deer with res-pect to race, sex and plane of n u t r i t i o n . Plane of Nu t r i t i o n C a l i - Van. fo r n i a Island Alaska J?ule Totals Deer M F M F M F M F High 6 7 6 3 4 2 6 3 37 I n i t i a l Low 2 4 3 1 2 0 2 2 16 Herd Low High 1 0 0 0 1 0 0 0 2 Uncommitted 3 8 11 Totals 9 11 9 3 4 7 2 8 85 66 Numbers of High individ u a l s Low with data for Low High 1000 days or more Totals 2 1 5 2 3 2 3 1 19 1 1 1 0 2 0 2 1 8 1 0 0 0 1 0 0 0 2 4 2 6 2 6 2 5 2 29 Weaning was accomplished by abruptly reducing the da i l y r a t i o n of milk as soon as s o l i d food was consumed regularly. The weaning period from the time the milk offered was reduced below the calculated d a i l y r a t i o n to the discontinuance of milk i n the diet, covered a short period of time. The weaning period for the 29 deer used i n subsequent growth analysis ranged from 4 to 32 days with an average of 14 days. Since the method used i n weaning depended upon the voluntary consumption of s o l i d food before reducing the milk ration, i t was possible for 39 differences to occur between races i n the length of the weaning period and i n the age and weight at weaning. The average weaning period was found to be longer for the Vancouver Island race of the Columbian Bl a c k - t a i l e d deer (20.2 days) than for the Ca l i f o r n i a n race (9.7 days), the Alaskan, Sitka deer (11.0 days) and the Mule deer (13.7 days). The average age at weaning for the 29 deer used for growth studies was 53.3 days with a range of 30 to 76 days. S i m i l a r l y , the average weight at weaning was 17.6 pounds with a range of 12.5 to 25.5 pounds. Racial d i f -ferences i n the age and weight at weaning were small. However, the Vancouver Island race showed a s l i g h t l y higher average age at weaning than did the other races but weighed the same as a l l other races. The increased age at weaning for thi s race i s attri b u t a b l e to the longer weaning period required. FOOD CONSUMPTION The quantities of milk or ration #15-56 offered to each deer and the quantity consumed was recorded d a i l y throughout the experiment. The regular measurement of body weight permitted the upwards adjustment of the quan-t i t i e s offered i n accord with the feeding schedules and .the plane of n u t r i t i o n . During the suckling period the 40 fawns consumed their entire d a i l y ration except during periods of i l l n e s s . In the post-weaning period, however, the high plane deer were unable to consume the d a i l y ration offered while the low plane deer always consumed the entire amount. In addition, i t was found necessary to increase the da i l y ration of the low plane deer because of their poor physical condition. Thus the low plane deer consumed more than the calculated 50% of the high plane l e v e l throughout the experiment. Because of the necessity to increase food consumption i n the low plane deer during the winter i t i s d i f f i c u l t to assess the exact r e l a t i o n -ship between the two planes of n u t r i t i o n i n terms of food consumed. D i f f i c u l t i e s i n assessment of the two planes of n u t r i t i o n were further increased by a voluntary reduction i n food intake by high plane males during the rutting period. Consequently, the growth patterns shown by the two groups are a r e s u l t of two d i f f e r e n t planes of n u t r i -tion whose mathematical r e l a t i o n s h i p i s not clear. Records of d a i l y food consumption were not analysed i n t h i s study. These data are available from Dean I. McT. Cowan of the University of B r i t i s h Columbia and from the author. MORTALITIES AND THEIR CAUSES During the suckling period, a t o t a l of 13 fawns died, 10 from an i n f e c t i o u s white scours which was probably caused by a virus or bacterium and three from other causes. A t o t a l of 40 fawns contracted the infec t i o u s scours but from a t o t a l of 33 which were treated with aureo-mycin at 5 mgm per day for three days, only three succumbed. Seven fawns were not treated and a l l died, thereby i n d i c a -ting the value of aureomycin i n the treatment of this disease. Fawns which died of th i s disease ranged i n age from seven to twenty-six days. The i n f e c t i o n persisted i n a mild form i n some fawns beyond this age, however, none of these animals died as a r e s u l t . The remaining three pre-weaning deaths were attri b u t a b l e to pneumonia and two cases of accidental death. The causes of a l l deaths up to 1000 days of age are shown i n Table C of the Appendix. Infectious white scours caused 33.3% of the t o t a l deaths, rumen malfunction, pneumonia and malnutrition 26.7%, accidents 20.0% and other causes 20.0%. In terms of the races of deer represented i n the o r i g i n a l herd 40% of the C a l i f o r n i a deer, 11% of the Alaskan deer, 50% of the Vancouver Island race and 62% of the Mule deer died within 1000 days after b i r t h . In addition to the l i s t e d deaths, seven deer escaped from the pens thereby leaving a t o t a l of 29 deer for which data was c o l l e c t e d for 1000 days or more. The d i s t r i b u t i o n , with respect to sex and the plane of n u t r i t i o n of the deer sur-viving to 1000 days of age i s shown i n Table IV. 42 PARASITES, INFECTIONS, DISEASES AND TREATMENT The entire herd was found to be free of a l l i n t e r n a l parasites with the exception of a few tapeworm c y s t i c e r c i found at autopsies. These cysts occurred on the mesentaries where they produced no pathological e f f e c t s which might influence growth. Deer louse f l i e s and b i t i n g l i c e were found on many deer i n the f i r s t summer but only one deer was severely infested. The fawns were sprayed with Lindane which e f f e c t i v e l y reduced the external parasites. One deer died as a r e s u l t of Lindane poisoning and four others displayed e p i l e p t i c - l i k e seizures on the day follow-ing spraying. These four recovered from mild Lindane poisoning probably caused by l i c k i n g their sprayed pelage. Bronchial d i f f i c u l t i e s were encountered i n some deer but treatment with aureomycin t r i p l e sulpha was ef f e c -ti v e i n eliminating coughing as i t arose. At least eight deer i n their f i r s t year had hard lumps on the lower jaw, at the angle of the jaw or i n the f l o o r of the mouth. This disease or i n f e c t i o n was not diagnosed and i n only one case did the lump suppurate. The symptoms resembled those des-cribed for a c t i n o b a c i l l o s i s . Deer with lumps on the jaws were injected intromuscularly with 100,000 I. U. of a y e r c i l -l i n p e r i o d i c a l l y . This treatment did not appear to be effective because the lumps continued for several days. Eventually, however, the lumps decreased and did not recurr. 43 One fawn developed a badly infected l e f t front foot. The abscess was lanced, disinfected and dressed with sulphathiazole. The abscess was l a t e r poulticed with Epsom s a l t s and 100,000 I. U. of a y e r c i l l i n were injected i n t r a -muscularly. This treatment resulted i n complete healing. Several fawns developed discharges from the eyes. The eyes were bathed with boric acid solution and opthalmic aureomycin was placed on the conjunctiva. The condition was quickly cleared by this treatment. Infectious white scours was the most serious disease encountered. A l l fawns were given 5 mgm per day of aureomycin for the f i r s t ten days after reaching the Research Farm but th i s treatment did not prevent the d i s -ease from occurring. Eventually 10 fawns died as a r e s u l t of the disease and t h i r t y others which contracted the d i s -sease were cured eventually by treatment with aureomycin. In some cases, the disease was prolonged i n duration and i t undoubtedly affected the rate of growth during the period of i l l n e s s . However, since a l l fawns had some form of scours at one time or another i t i s impossible to determine the degree of growth retardation which might have occurred as a r e s u l t of i n f e c t i o u s white scours. THE EFFECT OF PLANE OF NUTRITION ON CONDITION AND BEHAVIOUR High plane deer d i f f e r e d i n condition and behavi-our from their low plane counterparts. Body growth was 44 rapid i n the high plane group with the r e s u l t that their bodies were f i l l e d out and possessed the c h a r a c t e r i s t i c s of well^conditioned animals. Low plane deer were thin and frequently emaciated with the abdomen appearing dispropor-tionately large (see Fig . 7). The antlers of the high plane males were well developed i n the f i r s t year with approximately one inch of antler bone protruding through the epidermis. In the second growth season, most high plane males grew large forked ant-l e r s while some Vancouver Island B l a c k - t a i l e d deer produced strong single spikes about six to eight inches i n length. In subsequent growth periods, these deer developed large, heavy, multi-branched antlers. In contrast, low plane males did not produce clear bone antlers i n their f i r s t year. Instead, antler buttons were formed which did not protrude through the epidermis. In subsequent years, ant-l e r s of low plane males were short and weak and frequently did not exceed three inches i n length. The pelage of the high plane deer was long and sleek, even during the molting periods. In contrast, the pelage of the low plane deer was rough, dry and tended to protrude outwards from the body during the summer. In the f a l l and winter these deer chewed o f f , rubbed off or other-wise removed the terminal portions of the hair from the accessible portions of their bodies, leaving a coat of 45 Figure 7 . Sitka B lack - ta i l ed deer showing the ef fects of the plane of nutrition upon body conformation, pelage and antler development. High plane males (a) S (c) , low plane males (b) 8 ( d ) . 46 short grey hair (see Fi g . 7). Molt and the onset of reproductive behaviour was retarded i n low plane deer. Furthermore, the high plane males started their reproductive behaviour e a r l i e r and maintained sexually agressive behaviour patterns for a much longer period of time than did the low plane males. High plane males over two years of age retained some aspects of the aggressiveness associated with rut throughout the year. In t h i s way there was both a q u a l i t a t i v e and a quantitative difference i n behaviour patterns associated with the two planes of n u t r i t i o n . The high plane deer were always a l e r t and aggres-sive. As fawns, they spent some time i n play and were frequently seen f r o l i c k i n g i n the i r pens. The low plane fawns did not play but spent a l o t of time searching and, whenever they were found, c l o t h and straw would be eaten. Rather than being a l e r t and aggressive, they were timid, lacked nervous energy and when standing tended to crouch as can be seen in; F i g . 7. No quantitative appraisal was made of the differences i n behaviour att r i b u t a b l e to the plane of n u t r i t i o n but there i s no doubt that behaviour i s d r a s t i c a l l y altered by a low calory diet . BODY WEIGHT AND LINEAR MEASUREMENTS Body weight and lin e a r measurements taken at 47 various i n t e r v a l s throughout the experiment constitute the r e s u l t s used i n the analysis of growth patterns i n four races of deer. During early growth the deer were weighed every second day and body measurements were recorded each week. The i n t e r v a l between measurements was l a t e r increased to 15 days and then to one month. Si m i l a r l y , the i n t e r v a l between body weight determinations was increased to seven and then to 10 - 15 days during the f i r s t two years. Subsequently body weights were obtained at infrequent i n t e r v a l s up to f i v e years of age but with s u f f i c i e n t frequency to permit the con-s t r u c t i o n of growth curves. These r e s u l t s are too bulky to include.here and have therefore been placed on f i l e with Dean I. McT. Cowan at the University of B r i t i s h Columbia. The raw data used i n the analysis of growth patterns were obtained only from those deer which survived to a minimum of 730 days of age. This was necessary because two years of data were considered a minimum before growth patterns could be established i n s u f f i c i e n t d e t a i l for the comparison of r a c i a l differences. Thus body weights and li n e a r measurements from 29 deer which reached the age of 745 to 1731 days of age were used for the analysis which i s discussed i n the following section. 48 DISCUSSION PART I. PATTERNS OF GROWTH IN BODY WEIGHT FOR INDIVIDUAL DEER OF EACH RACE WEIGHT GROWTH OF HIGH PLANE MALE BLACK-TAILED DEER Weight-at-age data for high plane male black-t a i l e d deer, when plotted a r i t h m e t i c a l l y , demonstrate a rhythmic pattern of rapid increase followed by periods of weight s t a s i s or weight loss. Figure 8, representing the accumulative course of growth for experimental deer number 92L graphically i l l u s t r a t e s t h i s pattern which i s t y p i c a l of the growth curves of a l l the high plane experimental deer used i n t h i s study. This phasic type of growth was oriented seasonally and i t occurred i n spite of the provi-sion of a constant and i d e a l n u t r i t i o n a l environment. The periods of weight s t a s i s or weight loss, which occurred during the f a l l and winter, were associated with periods of reproductive a c t i v i t y and a concomitant reduction i n food intake. With the onset of early spring, rapid increases i n weight occurred which compensated for l o s t weight and resulted i n a series of increasing seasonal maximum values. The rates of growth during these periods were approximately equal i n f i v e successive growth phases as shown i n Fig. 8. It i s apparent however, that the rate of gain r e l a t i v e to weight, decreased with each succeeding year, thereby d i c -tating that a maximum weight would be reached at a future 300 250 (0 .o 200 o CD 150 "off feed 100 50 -Comparative summer growth rates off feed shed antlers Fig. 8. The actual and effective weight growth of a high plane male deer. (No. 92 L) Ouration of summer growth phases 200 400 600 800 1000 Age in days 1200 1400 1600 CO 50 and s p e c i f i c age. The magnitude of weight loss d i f f e r e d i n each ensuing year. During the f i r s t growth interruption deer number 92L l o s t weight over a b r i e f period, regained i t and continued to grow at a much reduced rate throughout the remainder of the winter. Most of the other experimental high plane males showed no weight loss during t h i s period but continued their growth at a reduced rate u n t i l the on-set of the second phase of rapid growth. In the second winter, some deer were able to maintain body weight as shown by 92L while others l o s t weight. In the following periods of growth depression, weight loss was marked. This indicates that the growth impulse i n deer i s subject to age-specific interruptions of increasing magnitude associ-ated with the reproductive period and depressed winter growth. If only the maximum seasonal weights are consid-ered, a curve can be drawn through these points as shown by curve "a" i n Fig. 8. This curve represents the course of weight growth without consideration for seasonal weight fluctuations. Curve "a" therefore represents the "ef f e c -t i v e " growth pattern r e l a t i v e to an ultimate maximum siz e which was only achieved seasonally. If the data represent-ing the f i r s t phase of growth are also considered (shown as curve "b") then the pattern of e f f e c t i v e growth from b i r t h i s sigmoid i n nature and si m i l a r i n general outline to many 51 c l a s s i c a l examples. The e f f e c t i v e growth curve of deer d i f f e r s from other published curves, i n that the region of i n f l e c t i o n appears to occur i n the neighbourhood of 25% of the mature weight, as opposed to the 50% shown by a symmetrical s i g -moid, or 30% as indicated by Von Bertalanffy's equation (L. Von Bertalanffy, 1938, 1949, 1957) and the Pearl-Read modified l o g i s t i c (Peal and Reed, 1923; F e l l e r , 1940). However, i t i s important to note that the region of i n f l e c -tion, at approximately 90 lbs i n deer No. 92L precedes reproductive behaviour by only a b r i e f period. This f i n d -ing i s therefore i n keeping with the hypothesis of Brody (1945) that the i n f l e c t i o n point i s generally coincidental with puberty. The notations on F i g . 8 indicate that a rhythmic reproductive pattern a f f e c t s the actual course of growth. In the f i r s t year, deer No. 92 v o l u n t a r i l y reduced i t s food intake at a point approximately 40 days after the i n f l e c -tion point of the e f f e c t i v e curve and j u s t p r i o r to the point where the actual course of growth deviates from the e f f e c t i v e growth curve. During t h i s period the buck fawn was sexually aggressive. At the end of the period of reduced growth, an antler button was l o s t and growth resumed at a rapid rate. At the end of the second growth period, the velvet was shed from the antlers and shortly 52 afterwards, the buck went o f f feed and became sexually aggressive once more with a reduction of food intake. The same pattern repeated i t s e l f i n successive years, except that weight was l o s t during the rut instead of being maintained or added to at a reduced rate. A s i m i l a r pat-tern of growth was found for a l l high plane deer. The annual reproductive rhythm induced a series of "troughs" i n the course of weight growth, as shown i n Fig. 8. The minimal winter weights may be used to con-str u c t another curve of weight change sim i l a r to the e f f e c -t i v e pattern of growth (Fig. 9). If the weight at b i r t h i s considered as well as the minimum winter weights, the resultant curve represents a base to which seasonal incre-ments are added. This curve may also represent the actual course of growth of f a t - f r e e body mass since i t i s suspec-ted that the body was r e l a t i v e l y free of f a t at the time minimum winter weights were reached (See Wood e t - j i l . 1962). It i s not known, however, i f the negative growth resulted in a loss of proteinaceous mass during the periods of f a t u t i l i z a t i o n . Further work i s necessary to c l a r i f y the physiological s i g n i f i c a n c e of the basic growth curve. Furthermore, the "basic" curve introduces the following mathematical d i f f i c u l t i e s which do not occur i n the r e l a -t i v e l y simple description of e f f e c t i v e growth. The f i r s t point representing the basic pattern of extrauterine growth must be the b i r t h weight, since i n t h i s I I I 1 I 1 1 I I I I I ' • I 200 400 600 800 1000 1200 1400 1600 Age in days 54 scheme, animal growth must be added to what i s present at the beginning of the growth period. The basic growth curve may then be constructed on the basis of the following assumptions: (i) I t i s assumed that at the opposite end of the curve, the e f f e c t i v e and basic growth curves are p a r a l l e l as they approach i n f i n i t y , ( i i ) That the minimum values i n the t h i r d and fourth winter l i e on or near the curve of basic growth. The f i r s t two assumptions per-mit the use of a Walford graph i n the evalua-tion of A and indicate that k (effective) = k (basic). ( i i i ) That the entire curve of basic growth may be expressed by the formula W = A - Be" k t. This assumption does not imply that the basic curve i s not sigmoid i n form, but simply suggests that the equation has predictive value, (iv) In the absence of a value for b i r t h weight, i t i s assumed that the e f f e c t i v e and basic curves are i n s i g n i f i c a n t l y d i f f e r e n t at 22 days of age. The i n s e r t i n F i g . 9 shows that i f the values of minimum weights for the 3rd and 4th winters are used i n a Walford projection, p a r a l l e l to the rate obtained for the e f f e c t i v e curve of growth, an estimate of 268.34 lbs i s obtained for the value of A. This value and the weight at 55 age 22 days may then be used to solve the equation W = A -Be~ k t. The resultant curve (1) i s shown i n Fig. 9 and i t was found that W = 268.34 - 2 6 0 . 7 5 e - 0 - 0 0 1 9 1 9 t . The u t i l i -zation of 268.34 lbs for the value of A r e s u l t s i n a B value of 260.75 lbs and an estimated b i r t h weight of 268.34 - 260.75 or 7.59 lbs. Since this value i s not unreasonable, i t indicates that the configuration of the curve suitably represents the very early data, p a r t i c u l a r l y when assumption (iv) i s considered. Curve (1) i n F i g . 9 passes through the actual growth curve near the values representing the minimums for the second and t h i r d growing seasons. This suggests that, i f the basic curve i s correct, actual growth approached the basic curve at these two points. During the t h i r d and fourth winters the calculated basic curve l i e s above some of the observed values. P h y s i o l o g i c a l l y t h i s could mean that during the f i r s t and second winters, the animal u t i l i z e d body food stores without protein loss, while dur-ing the t h i r d and fourth winters, protein was u t i l i z e d as well as f a t . On the other hand, i t could indicate that i n the f i r s t and second winters, not a l l f a t stores were u t i l i z e d whereas i n subsequent winters a l l or nearly a l l fa t reserves were depleted. If t h i s a l t e r n a t i v e were found true, i t would indicate that t h i s method of establishing a basic curve of growth does not r e s u l t i n a picture of the curve of f a t - f r e e body growth. This i s thought to be the 56 case because i f the difference between the actual peak value and the computed basic value at the same age i s obtained, i t should represent only f a t . For deer 92L the percentage f a t obtained i n t h i s manner for each succeeding maximum value of actual weight i s 27.5, 25.5, 22.9, 22.1 and 21.9 lbs respectively. Such findings c o n f l i c t with the general observation that animals tend to have the same or greater percentage of f a t at older ages (see Bailey, et a l . 1960). However, only by actual measurements of fat reserves throughout the course of growth can i t be determined i f the method used here s a t i s f a c t o r i l y represents a method of assessing f a t reserves and hence represents the course of f a t - f r e e growth. If i t i s assumed that observed values should never f a l l below the basic curve, then one or another of the assumptions made previously, must be i n error. (i) As growth approaches i n f i n i t y , the e f f e c t i v e and basic curves are not p a r a l l e l i n terms of a Walford expression. In order to lower the curve to pass through or below the minimum t h i r d and fourth winter values, A would neces-s a r i l y be less than 268 lbs. The al t e r n a t i v e to decreasing the value of A i s to permit the curve to reach the asymptote of the e f f e c t i v e curve while in t e r s e c t i n g the X-axis at a reasonable b i r t h weight of about 7 lbs. 57 Calculations indicate that the equation W = A - Be~ k* cannot be made to f i t t h i s s i t u a t i o n without a l t e r i n g the estimated b i r t h weight beyond reason. In addition, such a curve would have no more value than a straight l i n e running from b i r t h to 343 lbs and would imply that the animal would gain and loose no weight after the mature si z e of 343 lbs has been reached. ( i i ) The minimum values for the t h i r d and fourth winters l i e on a basic curve of growth but the Walford transformation y i e l d s a value which i s too large. Curve number (2) on Fig. 9 i s the r e s u l t of a r b i t r a r i l y reducing the value of A to 250 lbs while keeping the remaining assumptions constant. This curve meetsathe requirements that the observed values l i e on the basic curve by reducing the deviations of the t h i r d and fourth winter minima about the calculated curve. I t also r e s u l t s i n an estimated b i r t h weight of 8.0 lbs which would appear to be too large and thereby indicates a r e l a t i v e l y poor f i t for early growth data. It i s more l i k e l y that the actual b i r t h weight i s something less than the 7.59 lbs calculated from curve number (1). 58 ( i i i ) The equation W = A - B e - k t may not f i t the curve of basic growth, but u n t i l such time as experimental evidence i s available for the establishment of comparative points, t h i s curve i s as suitable as others and has the advantage of s i m i l a r i t y with respect to the e f f e c t i v e curve of growth. As a r e s u l t of ( i i ) above, i t i s i n t e r e s t i n g to note that i f one assumes curve (2) to represent the course of growth for f a t - f r e e body mass, the percentage f a t for each successive maximum i s 26.9, 28.6, 27.1, 27.2 and 27.1 respectively. These estimates imply that f a t storage i n r e l a t i o n to t o t a l body mass reached a maximum at the peak of the second growth phase and thereafter remained r e l a -t i v e l y constant. Only by experimental measurement of body composition can the foregoing considerations be tested. I t i s s u f f i c i e n t , for present purposes to note that a basic curve of growth can be constructed with the foregoing methods and that speculatively, the method may have some predictive value i n terms of minimum winter weights and may even constitute a method of estimating the percentage of f a t stored through each growing season. However, i n view of the mathematical d i f f i c u l t i e s i n f i t t i n g an adequate curve to the minimum values and the b i o l o g i c a l d i f f i c u l t i e s involved i n interpreting the basic curve without further experimentation to determine body composition, the "basic" 59 curve i s not given further consideration with respect to the description of growth or to the comparison of r a c i a l , sexual and n u t r i t i o n a l differences i n growth patterns. SEXUAL DIFFERENCES IN THE ACTUAL AND EFFECTIVE GROWTH PATTERNS OF HIGH PLANE DEER Weight-at-age data for male and female deer resulted i n sim i l a r patterns of actual and e f f e c t i v e growth when they were raised i n the same environment. Seasonal maximum and minimum weights were reached at approximately the same dates, but the magnitude of seasonal weight fluctuations and absolute body siz e was reduced i n the growth pattern of the female (Fig. 10). The e f f e c t i v e pattern of growth i s sigmoidal i n both sexes, thereby per-mitting the use of the methods established for high plane male deer for comparisons of growth. In the s e l f - a c c e l e r a t i n g and pre-pubertal phase of growth, female No. 37L grew more rapidly than did male No. 32L as shown by the instantaneous r e l a t i v e growth rates of 1.58% and 1.41% respectively (Equations 32L/(1) and 37L/(1) on F i g . 10). This r e l a t i o n s h i p was found to occur i n 15 out of 21 comparisons, in d i c a t i n g that a s i g n i f i c a n t difference occurs i n the pre-pubertal instan-taneous r e l a t i v e growth rates, (X 2 = 7.714; P Q 0 1 = 8.260 for 20 d . f . ) . The v a r i a b i l i t y i n growth rate was s u f f i c i -ently high and the sample size s u f f i c i e n t l y small, to ,, — I ' 1 ' 1 1 1 1 1 1 I • • I 200 400 600 800 1000 1200 1400 1600 Age in days 61 preclude the demonstration of quantitative differences i n growth rates by a " t " test. The s e l f - i n h i b i t i n g phases of growth shown i n Fig. 10 indicate that the rate of decline i n growth rate i s almost twoice as rapid i n the female (0.3261% per day) as i n the male (0.1728%). This means that the female reached an asymptotic weight by the end of her fourth year, while i n the male, the much higher asymptotic weight was reached at the end of i t s ninth year. The r e s u l t of these differences i n post-pubertal growth rate i s a marked degree of sexual dimorphism i n body si z e which was evident i n a l l high plane deer, with deer number 32L and 37L being used as examples. The s e l f - a c c e l e r a t i n g and s e l f - i n h i b i t i n g phases of growth i n t e r s e c t at 94 days of age (35 lbs) i n the female growth pattern and at 114 days of age (38 lbs) i n that of the male. This indicates that even though the female grew more rapidly than the male i n the s e l f -accelerating phase, the male reached the pubertal i n f l e c -tion point l a t e r than did the female. Thus the male had increased i t s weight by 160.7% while the female had increased by only 148.5%. Differences i n the magnitude of male and female e f f e c t i v e growth rates may be a t t r i b u t a b l e to physiological differences associated with sex, to i n d i v i d u a l genetic differences coupled with small sample sizes, or to differences i n b i r t h weight. The preponderance of females which grew faster than males tends to rule out i n d i v i d u a l genetic differences because otherwise, one would expect only 50% of the females to grow faster than males. Fur-thermore, the calculated b i r t h weight was higher i n the female (7.83 lbs) as compared with that of the male (7.53 l b s ) , yet the calculated rates of growth are reversed i n magnitude from the expected re l a t i o n s h i p of r e l a t i v e growth rates i f b i r t h weight were the contributing factor. For these reasons, i t i s suspected that the faster rate of pre-pubertal growth i n the female i s related to sex and hence to hormonal factors. THE SEASONAL PERIODICITY OF GROWTH The actual course of growth follows a seasonally rhythmic pattern of fluctuations i n the magnitude and direc-tion of weight changes. The same pattern of weight change i s shown by both sexes and i t appears to be related to physiological changes i n the animals associated with rhythmic reproductive a c t i v i t y . In contrast to deer i n their natural habitat, the experimental deer were offered the same die t throughout the year, thereby removing the influence of changes i n the quality and.quantity of the food supply upon the pattern of weight change. The rate of po s i t i v e summer growth was remarkably si m i l a r i n each suc-ceeding period of growth, as shown graphically for the male 6 3 i n the inset of Fig. 8. The apparent constancy of absolute summer growth i s related to the a b i l i t y of animals to com-pensate for retarded weight development or weight-loss by growing more rapidly than would occur under conditions which permit continuous growth. However, because si m i l a r seasonal rates of growth are achieved by progressively larger animals, growth rates r e l a t i v e to body siz e decline with each ensuing growth period thereby giving r i s e to a sigmoid curve of e f f e c t i v e growth. Growth control i n deer i s therefore si m i l a r to that of other animals but the con-t r o l i s exercised intermittently i n the production of a f i n i t e body s i z e . The degree of growth suppression d i f f e r e d i n each ensuing winter period. In the f i r s t , growth tended to continue throughout the winter at a greatly reduced rate, as shown i n ; F i g . 10. Similar winter growth patterns have been established for c a t t l e (MacDonald, 1958; Brookes and Hodges, 1959). In the second and subsequent periods of growth suppression, a progressively increasing amount of weight was l o s t . It i s therefore evident that the factors i n t e r f e r i n g with growth become progressively more severe as the animal increases i t s si z e . The r e l a t i v e l y abrupt changes i n growth rates from summer to winter were associated with c e r t a i n anatomi-c a l and behaviour changes related to reproductive a c t i v i t y . 64 In the males, the termination of periods of rapid growth coincided with•the drying and loss of antler velvet. At the same time the bucks became aggressive towards other deer and towards th e i r human handlers, (see Cowan and Geist, 1961). With the onset of thi s aggressive, reproductive behaviour, the bucks reduced their d a i l y food intake, thereby decreasing the food energy supply while at the same time they increased their energy needs through increased a c t i v i t y . The imbalance i n food energy intake and requirements resulted i n a rapid cessation of growth as i s shown by the s i m i l a r i t y i n patterns of growth and food intake (Figs. 10 & 11). The s i m i l a r i t y i n these patterns indicates that the metabolic interference i n the expression of growth r e s u l t s d i r e c t l y from interference with factors governing food consumption. Furthermore, since the pattern of growth and of food intake d i f f e r s i n each ensuing period of growth suppression, i t indicates that the i n t e r f e r i n g metabolic factors d i f f e r quantitatively and q u a l i t a t i v e l y as siz e increases. This point i s i l l u s t r a t e d i n F i g . 11 where i t may be seen that throughout the f i r s t period of growth suppression food intake was simply reduced, whereas i n ensuing periods of suppression two le v e l s of food consumption are apparent; a very low l e v e l (a) which was maintained for a short period of time, and a higher l e v e l (b) preceeding the intake associated with rapid growth. Rapid summer growth was resumed with increased d a i l y food consumption. The commencement of renewed growth Average daily food intake in ounces 0)1 o r o 59 66 coincided with the loss of antlers, the commencement of new antler growth and a moult from winter to summer pelage. The seasonal pattern of growth and food intake was s i m i l a r i n both sexes. However, the magnitude of changes i n weight and food consumption was less i n the females as shown i n Figs. 10 & 11. In female deer the behavioural expressions of the seasonal physiological cycle were few and probably sh o r t - l i v e d . Thus, there was l i t t l e d i s c e r n i b l e overt influence of behaviour per se, on food intake. The reduction of food intake i n the females i s therefore a d i r e c t expression of physiological changes a f f e c t i n g the need for food, similar to the second l e v e l of food intake demonstrated for the males during periods of growth suppression (see F i t t , 1941). The actual growth curves of four high plane male deer, representing four races have been plotted with res-pect to date i n F i g . 12. This graph i l l u s t r a t e s that a seasonally rhythmic pattern of growth i s common to a l l four races but differences e x i s t i n the dates at which peak weights are reached. Since these peaks are c l o s e l y related to the onset of reproductive capacity, they may be used to represent s i m i l a r i t i e s and differences i n the timing of reproduction. Even though environmental factors such as l i g h t , temperature and food supply were i d e n t i c a l for a l l experimental deer, comparable points i n the growth curves Fig. 12. The seasonal growth of high plane males l 1 1 1 1 1 i i i May 7 Nov.23 JuneII Jan.8 July27 Feb. 12 Sept. I March 18 Oct.5 1956 1957 1958 1959 I960 68 occurred f i r s t i n the Ca l i f o r n i a n B l a c k - t a i l s , followed i n order by the Mule deer, Alaskan and the Vancouver Island B l a c k - t a i l e d deer. The onset of moulting, shedding of antler velvet and antler-drop also followed t h i s same pat-tern. I t i s therefore apparent that an innate pattern of timing existed with respect to seasonal physiological changes which was not masked by the relocation of repre-sentatives of the various stocks i n one geographical position. However, a progressive adjustment was made i n the f i r s t three years of l i f e as i s shown by the spread of comparable points i n Fig. 12. This indicates that the innate timing mechanism was adjustable, even though adjustments were made slowly. (The apparent deviation from th i s adjustment i n the l a s t peaks shown, i s believed due to infrequent weighings which did not permit the determination of the actual peaks.) Environmental factors which trigger reproductive a c t i v i t i e s and other physiological changes are quantita-t i v e l y d i f f e r e n t at various geographical l o c a l i t i e s . A l l such factors therefore alter: i n a seasonally regular man-ner at a single geographical point. One i s therefore able to inspect the order of seasonal changes of such factors from the standpoint of order of occurrence of the change produced i n four stocks of animals. For example, the order of occurrence of sim i l a r points of the growth curves indicates that the number of hours of daylight and the i n t e n s i t y of daylight are not the evocators of rut, since the order of occurrence of rut i s reversed from that expected from progressive seasonal change i n the area of o r i g i n . S i m i l a r l y , the observed order rules out such fac-tors as temperature, the r a t i o of day to night, and the quantity of solar energy as evocators of reproductive a c t i v i t y . Other factors such as the quantity of night or lack of sunlight, the night to day r a t i o and perhaps even the duration and i n t e n s i t y of moonlight may be involved i n invoking reproduction since their r e l a t i v e magnitudes at d i f f e r e n t l a t i t u d e s give r i s e to the observed order. The present data do not permit the selection of one or other of these possible evocators. Fig. 11 does, however, permit one to rule out the e f f e c t of s i z e and growth rate as a f f e c t i n g the time at which reproductive a c t i v i t y i s i n i t i a t e d , since the Mule deer i s the largest and grows most rapidly, yet i s second to the C a l i f o r n i a n B l a c k - t a i l i n order of occurrence of maximum seasonal weights. THE EFFECT OF A LOW PLANE OF NUTRITION ON GROWTH Individuals of each of the four races were placed on a post-weaning plane of n u t r i t i o n which was calculated at 50% of the high-plane r a t i o n . These deer consumed a l l of their d a i l y r a t i o n throughout most of the experimental period, whereas the high plane deer seldom ate their f u l l r a tion and v o l u n t a r i l y reduced food intake during the 70 reproductive period. This means that the low plane deer consumed more than 50% of the ration consumed by high plane deer. In addition, i t was found necessary to increase the dai l y r a t i o n during the winter, over and above the calcu-lated low plane l e v e l . The need for an increased feeding l e v e l for low plane deer during the period when the high plane animals v o l u n t a r i l y reduced th e i r food intake i s probably related to an absence of stored food material i n the low plane group. Without stored food material, i n s u l a -tion i s reduced and heat loss increased i n correspondence to decreased ambient temperatures. An increased food supply for low plane deer was thus found necessary to maintain l i f e . As a r e s u l t , i t i s d i f f i c u l t to assess the exact rela t i o n s h i p of the low plane with respect to the high plane of n u t r i t i o n . The low energetic plane, which was thought not to invoke s p e c i f i c d e f i c i e n c i e s , caused the curve of weight growth to be modified i n configuration. However, i t i s possible to recognize si m i l a r points on the high and low plane growth curves enabling comparisons to be made. The peak weights, shown i n Fig. 13, for a low plane Alaskan deer (No. 34) are the r e s u l t of additional winter feed and are therefore, not comparable to the peaks shown by the high plane deer (No. 32). During the summer, the plane of n u t r i t i o n was dropped to the calculated l e v e l and conse-quently some of the weight gained during the winter was J 1 1 1 1 1 1 1 1 I I I I I I I 200 400 600 800 100 200 300 400 500 600 , Age in Jays 72 l o s t i n early summer. Body weight was then maintained during the summer but suffered an abrupt decline following the shedding of velvet at the end of the second summer. Points a, b, and c, i n F i g . 13 are therefore believed to represent the same conditions, which are represented by a trough and two peaks shown by the high plane deer. In i, t h i s way, points were selected which permit the construc-tion of si m i l a r curves of e f f e c t i v e growth for both high and low plane deer. However, curves constructed through these points do not accurately represent the calculated plane of n u t r i t i o n because s k e l e t a l growth probably took place during the period of increased winter feeding which was not commensurate with the calculated low plane. Nevertheless, a s e l f - i n h i b i t i n g , e f f e c t i v e curve of growth may be constructed which represents a depressed plane of n u t r i t i o n . Curve two i n F i g . 13 indicates that an asymptotic value of 135 lbs was obtained with a value for -k of 0.001192, compared with 290 lbs and 0.001728 for the high plane male. The low plane of n u t r i t i o n therefore decreased the mature weight value by more than half (54%) and reduced the rate of decline i n growth rate. The construction of the e f f e c t i v e growth curve for the s e l f - i n h i b i t i n g phase indicated the approximate po s i t i o n of the point of i n f l e c t i o n , thereby permitting 73 the se l e c t i o n of data for the s e l f - a c c e l e r a t i n g phase which would not include data i n the region of the in t e r s e c t i o n point. These data were plotted i n semi-logarithmic fashion with the r e s u l t that two phases of l i n e a r i t y appeared (Fig. 13). The f i r s t phase represents the pre-weaning plane of n u t r i t i o n while the second represents post-weaning growth. Since the l a t t e r covered a longer period of time (71 to 178 days) and was related to most of the high plane s e l f -accelerating phase, i t was used for the establishment of a comparative equation. As a r e s u l t , i t was found that the rate of growth i n the low plane s e l f - a c c e l e r a t i n g phase was 0.607% per day compared to 1.417% per day for the high plane male. Thus, during t h i s phase the low plane buck grew at a rate of less than half (42.8%) of that shown for the high plane buck. The establishment of these two curves permitted the point of i n t e r s e c t i o n to be calculated with the r e s u l t that i t was found to occur at 189 days of age and a body weight of 37.5 lbs compared to 114 days of age, and 38.0 lbs for the high plane buck. This suggests that the i n t e r -section point or pubertal i n f l e c t i o n i s related to body weight and not to age. It i s also apparent that "puberty", i n terms of weight growth was reached i n the f i r s t year but i t i s uncertain whether i t would have done so i f the actual plane of n u t r i t i o n had been maintained at the c a l -culated l e v e l throughout the year. 74 In view of the foregoing, i t i s important to recognize that the rates of growth k and -k, and the asymptotic value "A" are genetic constants only with res-pect to a s p e c i f i c environment. This means that while growth i s related to weight already made and growth yet-to-be made, i n the two segments of the curve, the magnitude of these values i s d i r e c t l y related to environmental opportun-i t y , except where such opportunity permits the genetic maximum rate of growth. Thus, i f the values from the high plane buck are similar to, or the same as, the genetic maximum, the values for the low plane indicate that the environment was less than half as suitable for growth. The age-at-inflection may also be related to environmental opportunity, but i t would appear that the weight-at-inflec-tion may be a d i r e c t genetic constant which i s disassociated from environmental opportunity. I t w i l l be necessary to test t h i s with a large number of animals of a l l four races before i t can be established that such i s the case. Inspection of the actual course of growth reveals some features concerning the interferences of growth by the reproductive physiology of the animal. The sharp dip at point "a" i n Fig. 13, occurs i n the growth curves of a l l the bucks and i s associated with a digestive upset t y p i f i e d by a green scours. However, i f t h i s was due to an imbal-ance of diet, or t o ' b a c t e r i a l i n f e c t i o n , i t i s expected that the dip would occur at approximately the same date i n a l l i n d i v i d u a l s . F i g . 12 shows that t h i s dip did not occur at the same date and i t i s therefore thought to be related to the reproductive condition of the animal or to the cessation of reproductive condition. Since t h i s point occurs i n the low plane deer, i t suggests that the low plane deer reached the pubertal i n f l e c t i o n p r i o r to t h i s point, as was shown before. At points "b" and "c" body weight was l o s t i n spite of the fact that food was available at a l e v e l which previously maintained body weight within r e l a t i v e l y nar-row l i m i t s and i n spite of a weight d e f i c i t caused by the plane of n u t r i t i o n . A d d i t i o n a l l y , points "b" and "c" occur at s l i g h t l y e a r l i e r ages i n the low plane deer than i n the high plane. I t i s therefore suggested that a low plane of n u t r i t i o n causes gonadal hormones to a f f e c t the anterior p i t u i t a r y more rapidly and possibly at lower l e v e l s . Underfeeding has been found to decrease the p i t u -i t a r y output of gonadotropins and to decrease androgen a c t i v i t y (Rowson, 1959) but i t would appear that the i n t e r r e l a t i o n between these two hormones, i n a low plane deer, r e s u l t s i n favour of the gonadal hormones. The fact that weight was l o s t following the shedding of velvet, at point "b", tends to substantiate t h i s hypothesis because androgens tend to chemically hypo-physectomize the animal, leading to a marked loss of body weight, i n the same manner as has been found by the s u r g i c a l removal of the 76 anterior p i t u i t a r y (Brody, 1945). The period of growth suppression i n the low plane buck did not l a s t as long as i n high plane males. Moreover, the low plane bucks grew at a more rapid rate during the winter than i n the summer, p a r t i a l l y as a r e s u l t of the additional food offered i n winter. This indicates that reproductive interference ceased early i n the winter and proves that deer are capable of growth during t h i s period provided that the food supply i s adequate and provided that reproductive conditions do not i n t e r f e r e . Even though reproductive condition was attained by the low plane males, i t i s not known i f the plane of n u t r i t i o n affected the quality of the reproductive state. Certainly, l i b i d o was markedly reduced i n the low plane males and i t i s l i k e l y • t h a t the development of the gonads and the a c t i v i t y of the accessory glands was delayed as was found by Rowson (1959), Moustgaard (1959), and Lutwak-Mann (1951). Within the experimental period the impulse to grow was not l o s t with increased age following the period of n u t r i t i o n a l l y suppressed growth. Fig. 14 shows the growth curves of one male (No. 30) which was continuously offered a high plane of n u t r i t i o n and a male whose plane of n u t r i t i o n was changed from low to high plane (No. 34) at 860 days of age. The l a t t e r was able to catch up to the j Fig. 14. The effect of a high plane diet upon early low plane growth. [•250 H200 — i 1 1 1 1 1 1 1 1 ' • » • * 200 400 600 800 1000 1200 1400 1600 Age in days 78 high plane deer i n body weight, within one growth season, thereby in d i c a t i n g the presence of a latent growth impulse. The difference e x i s t i n g between the body weights of these two animals at subsequent seasonal peaks are no larger than one might expect from i n d i v i d u a l genetic variations i n high plane animals. This finding i s simi l a r to that reported by Morgulus (1913), Osborne and Mendel (1915), and by Stewart (1916), and emphasizes the fac t that although size i s the basic correlate of growth, the magnitude of the growth rate i s related to environmental opportunity and r e f l e c t s the genotype only when the environment i s maintained at a con-stant s p e c i f i e d l e v e l . INSTANTANEOUS RELATIVE RATES OF INCREASE FOR SUMMER GROWTH It was previously shown that weight increase i s proportional to body siz e (W) during the se l f - a c c e l e r a t i n g phase of e f f e c t i v e growth, whereas i t i s proportional to weight yet-to-be-made (A - W) i n the s e l f - i n h i b i t i n g phase. The same i s obviously true with respect to each seasonal phase of growth, since the curves of summer growth accelerate from winter depression and are in h i b i t e d with the onset of rut. Therefore, i n order to treat each summer growth phase with respect to acceleration and i n h i b i t i o n , two constants (k and -k) are required. However, actual growth at any given instant must be proportional to the mass of the energy-converting machinery even though i t 79 occurs i n the s e l f - i n h i b i t i n g phase. Thus i n h i b i t i o n ,. changes the magnitude of the proportionality constant but does not destroy the proportionality concept with respect to mass. For t h i s reason, and because the formula W = A e k t may be used to represent most of the data i n each summer growth period, the value of k may be used for comparisons of actual seasonal growth, provided that the data f i t s l i n e a r l y on semilogarithmic plot. The slopes of the summer growth phases shown i n F i g . 8 and the values shown i n Table V indicate that absolute gain may, at older ages, equal or exceed the gain at younger ages. However, since the gain of older animals i s made by a larger mass, r e l a t i v e growth declines with increasing s i z e i n the same manner as shown for the s e l f -i n h i b i t i n g phase of e f f e c t i v e growth. This i s shown by consecutively decreasing values of instantaneous r e l a t i v e summer growth rates for i n d i v i d u a l s of each race of deer. Comparisons of the instantaneous r e l a t i v e growth constants for male deer of four d i f f e r e n t o r i g i n s indicates that seasonal growth tends to be proportional to the mature size of the race. Thus the values of k are larger for Mule deer than for the Vancouver Island deer. However, the k-values for Alaskan and C a l i f o r n i a n deer are interchanged with respect to r e l a t i v e s i z e s at the termination of the f i r s t phase of growth (see F i g . 12). This interchange was 80 due to the a b i l i t y of the Alaskan deer to grow for a longer period of time at a slower rate than was found for the Cal i f o r n i a n deer. In l a t e r phases, the Alaskan deer grew more rapidly than the Mule deer as shown by the instantan-eous r e l a t i v e growth rates. Table V. Instantaneous r e l a t i v e growth rates (k) and cor-responding absolute rates of gain (lbs per day) for periods of rapid summer growth. Race k i k 2 k 3 k4 k 5 Mule (92L) .016416 (.5313) .003437 (.5385) .002827 (.7143) .002569 (.6667) .002087 (.5342) Alaska (32L) .014167 (.3028) .003610 (.4128) .003105 (.5374) .002874 (.5235) C a l i f o r n i a (25L) .015178 (.4375) .003363 (.3108) .002001 (.2721) .001875 (.2953) .001791 (.2692) Vancouver Island (59L) .010956 (.2381) .003339 (.2715) .001799 (.2238) In phase two, growth rates were similar for a l l four races because each of the smaller animals correspond i n terms of growth to a younger age of the larger deer. Thus one may account for the larger k£ value for the Alaskan deer than for the Mule deer. However, i f thi s i s accepted, then one would also expect that the values for the C a l i f o r n i a n and Vancouver Island would exceed the value for the Mule deer. That such i s not the case, i s due to the ge n e t i c a l l y controlled rate of decline of the k- values and the r e l a t i v e mature sizes of the animals. The fact 81 that growth i s also proportional to weight yet-to-be-made changes the magnitude of the proportionality of growth and mass. In the t h i r d and fourth phases of growth, the growth rate of the Alaskan deer exceeds that of the Mule deer. The above explanation may also be invoked to explain t h i s difference. However, another factor probably augments the e f f e c t of si z e corresponding to a younger animal with somewhat sim i l a r asymptotic values. Prior to these two phases of summer growth, the Alaskan deer l o s t r e l a t i v e l y more weight than the Mule deer, as i s evident i n F i g . 12. The growth of the Alaskan deer then proceeded at a rate exceeding that of the same animal had i t l o s t the same r e l a t i v e amount of weight as the Mule deer. Thus the greater k3 and k4 values for the Alaskan deer involves a larger amount of compensatory growth t h a n ; i s the case i n the Mule deer, r e s u l t i n g i n higher Alaskan growth rates. The larger values of k for the Alaskan deer might also be conceived to indicate that the Alaskan deer grows i n a d i f f e r e n t manner and may eventually reach a si m i l a r weight to that of the Mule deer. That such i s not the case, was shown previously by the c a l c u l a t i o n of asymptotic weights of 290 lbs (deer 32L) and 343 lbs (deer 92L) for Alaskan and Mule deer respectively. The foregoing serves to i l l u s t r a t e that the rate 82 of seasonal growth i n a s p e c i f i c n u t r i t i o n a l environment, as measured i n an instantaneous and r e l a t i v e manner, i s proportional to mass, the difference between mass and mature weight and also to the nature and extent of weight changes immediately prior to the summer growth period. It also serves to i l l u s t r a t e that the instantaneous r e l a t i v e growth rate must be used cautiously, i f i t i s used to represent differences i n growth r e s u l t i n g from differences i n genetic o r i g i n . In the f i r s t year of l i f e , the instan-taneous r e l a t i v e growth rates indicate variations i n the genetic pot e n t i a l for growth and are therefore also i n d i c -ative of the r e l a t i v e e f f i c i e n c y of each i n d i v i d u a l i n the u t i l i z a t i o n of the environment for growth. In subsequent years, however, the values of k for seasonal growth periods may be related to factors other than the genetic growth po t e n t i a l , and may give r i s e to erroneous conclusions about the e f f i c i e n c y of the growth processes. In wild populations where the n u t r i t i o n a l environment i s never constant and i s d i s s i m i l a r from one range to another, the value of the environment for growth also a f f e c t s the instan-taneous r e l a t i v e growth constants, thereby eliminating seasonal growth rates as e f f e c t i v e c h a r a c t e r i s t i c s for the comparison of differences i n genetic potential for growth. 83 PART I I . RACIAL COMPARISONS OF THE INSTANTANEOUS RELATIVE RATES OF GROWTH IN BODY WEIGHT COMPARISONS OF FOUR RACES OF BLACK-TAILED DEER WITH RES-PECT TO THE EFFECTIVE GROWTH OF BODY WEIGHT IN HIGH PLANE MALES The foregoing has indicated that for purposes of r a c i a l comparisons, seasonal growth patterns give r i s e to d i f f i c u l t i e s of interpretation, p a r t i c u l a r l y where growth compensation r e s u l t i n higher rates of growth than are commensurate with the age of the animals. Furthermore, seasonal growth rates provide a series of values of k and -k, each requiring comparisons with a l l other values, thereby making interpretations d i f f i c u l t . The basic curve of growth i s also unsuitable for the comparison of growth patterns as a re s u l t of the b i o l o g i c a l and mathematical d i f f i c u l t i e s reported e a r l i e r . Therefore, the e f f e c t i v e curve of growth, represented by the equations W = Ae^* and W = A - B e - ^ , constitutes the most suitable method for comparisons. Weight-at-age data for each high plane male deer were treated by the method of least squares i n order to obtain instantaneous r e l a t i v e growth rates for the s e l f -accelerating (k) and s e l f - i n h i b i t i n g (-k) phases of ef f e c t i v e growth, as well as estimations of mature si z e . Small numbers of animals i n each r a c i a l group prevented the use of s t a t i s t i c a l techniques for the estimation of 84 population parameters. Nevertheless, the data serves to i l l u s t r a t e differences and s i m i l a r i t i e s of i n d i v i d u a l growth patterns which may be related to the r a c i a l o r i g i n of the ind i v i d u a l s . The instantaneous r e l a t i v e growth rates for the se l f - a c c e l e r a t i n g phase shown i n Table VI, indicate that the Mule deer tend to have a higher rate of growth than i n d i v i d -uals of the other three races. S i m i l a r l y , i n d i v i d u a l s of the Ca l i f o r n i a n race displayed much lower rates of growth than most of the ind i v i d u a l s i n the other three races. This sug-gests that the C a l i f o r n i a n deer and Mule deer represent d i f -ferent genetic o r i g i n s with respect to the achievement of growth i n a s p e c i f i c environment and also suggests that these two races d i f f e r from the Alaska-Vancouver Island B l a c k - t a i l group. The same pattern i s shown i n reverse by a r e l a t i v e l y low persistency (the rate at which growth p e r s i s t s as opposed to the rate of decline i n growth rate) rate for the Mule deer i n the s e l f - i n h i b i t i n g phase of growth, as shown i n Table VII. If r a c i a l parameters follow the same pattern shown by the small number of ind i v i d u a l s , the growth patterns suggest that genetic differences i n growth rate e x i s t between the Cal-i f o r n i a n Black- t a i l and Vancouver Island deer and that no es s e n t i a l difference e x i s t s i n growth patterns between the Vancouver Island and Alaskan deer. However, the estimated mature weights for these two races shown i n Table VII, tend to suggest that the Alaskan deer d i f f e r s from the Vancouver Island deer i n ultimate si z e , the Alaskan deer being p o t e n t i a l l y 85 larger i n a given n u t r i t i o n a l environment. Thus, both growth rates and mature size indicate that genetic d i f f e r -ences e x i s t between- these four races. Table VI. Instantaneous r e l a t i v e growth rates of high plane male deer of four races, i n the s e l f -accelerating phase of e f f e c t i v e growth (k x 100) Deer Califor-r Deer No. nian No. Alaska Deer Van. No. Island Deer Mule No. Deer 1 L 25L Av. 1.1226 1.1998 1.1612 30L 1.8057 32L 1.4167 38L 1.4106 Av. 1.5443 50L 1.6513 51L 1.6042 55L 1.4709 59L 1.1662 61L 1.4816 Av. 1.4748 90L 1.8645 92L 1.6412 94L 1.6604 Av. 1.7220 If the averages shown i n Tables V and VI are in d i c a t i v e of the rel a t i o n s h i p between r a c i a l parameters of the four stocks of deer, the Mule deer grows the f a s t -est i n the f i r s t ; year of growth (k) followed i n order by the Alaskan, Vancouver Island, and C a l i f o r n i a n deer. In the remainder of the e f f e c t i v e curve of growth, the C a l i -fornian deer grows more rapidly, as shown by the p e r s i s t -ency (p) of growth, followed by the Alaskan, Vancouver Island and Mule deer. The magnitude of the estimated ultimate s i z e (A) follows the same order as the f i r s t phase growth rates with the exception of the C a l i f o r n i a n and Vancouver Island deer, which are interchanged, the Ca l i f o r n i a n deer being larger i n ultimate size than the Vanoouver Island deer. 86 Table VII. Instantaneous r e l a t i v e growth rates for high plane male deer of four races i n the s e l f -i n h i b i t i n g phase of e f f e c t i v e growth showing estimated mature weights. C a l i f o r n i a No. A -k x 100 p x 100* 1 L 275 0.1239 0.8770 25L 215 0.1293 , , 0.8707 Ay. 245 0.1266 0.8739 Alaska 30L 230 0.1044 0.8956 32L 290 0.1728 0.8272 38L 340 0.1084 0.8916 Av. 287 0.1285 0.&715 Vancouver Island 50L 215 0.2224 0.7776 51L 270 0.1112 0.8888 55L 270 0.0959 0.9041 59L 180 0.1631 0.8369 Av. 234 0.1482 0.8518 Mule Deer 90L 295 0.2701 0.7299 92L 343 0.1919 0.8081 Av. 319 0.2310 0.7690 *p represents the persistancy of growth whereas -k repre-sents the decline of growth rate. Other growth c h a r a c t e r i s t i c s derived from the e f f e c t i v e curves of growth also indicate possible d i f f e r -ences i n the genetic pattern of growth. The estimated age at which ultimate size (A) i s reached i s greatly reduced for the Mule deer by comparison with the other three stocks (Table VIII). L i t t l e can be said of the age-at-maturity i n weight with regard to the C a l i f o r n i a , Alaska 87 and Vancouver Island deer because the v a r i a b i l i t y between indi v i d u a l s obviously reduces the r e l i a b i l i t y of the averages. Table VIII. Age and ultimate weight (A) and weights at the int e r s e c t i o n of f i t t e d s e l f - a c c e l e r a t i n g and s e l f - i n h i b i t i n g curves C a l i f o r n i a Alaska Van.Island Mule Deer Age at maturity Average Weight at i n f l e c t i o n Average 12.7 yrs. 10.93 yrs. 11.55 yrs. 72. lbs. 79. lbs. 75.5 lbs. 13.86 yrs. 14.50 yrs. 9.06 yrs. 12.47 yrs. 6.65 yrs. 13.70 yrs. 15.76 yrs. 8.66 yrs. 11.19 yrs. 5.87 yrs. 8.25 yrs. 7.06 yrs. 58. lbs. 42. 38. lbs. 44. 61. lbs. 48. 39. 52.3 lbs. 43.3 lbs. 42.5 lbs. lbs. 84. lbs. lbs. lbs. lbs. 63.2 lbs. As was mentioned e a r l i e r , the age at the point of inte r s e c t i o n of the s e l f - a c c e l e r a t i n g and s e l f -i n h i b i t i n g phases of growth ( i n f l e c t i o n point) did not appear to be consistent with respect to two d i f f e r e n t planes of n u t r i t i o n , but the i n f l e c t i o n weight was s t r i k i n g l y s i m i l a r i n both planes. Table VIII shows that in high plane male deer, the i n f l e c t i o n weight i s r e l a -t i v e l y consistent within each race and i t appears to be c h a r a c t e r i s t i c of the race. The adaptive si g n i f i c a n c e of thi s i s not clear, but i t i s apparent that the i n f l e c t i o n weight must be related to the rate of growth i n both phases and to the timing of the reproductive changes which t i p the scale of growth from increasing to decreasing 88 increments. In addition, i t i s l i k e l y that the timing of the onset of physiological changes associated with rut are s i z e - s p e c i f i c and are related to the genetic constitution of the i n d i v i d u a l and of the race. In any case, the average i n f l e c t i o n weights tend to indicate further, that genetic differences e x i s t i n a l l four races studied. Even though the experimental deer were main-tained i n i d e n t i c a l environmental conditions, other fac-tors such as age-at-weaning and length of ifehe weaning period may have affected the pattern of growth. In Table IX, a l l high plane males have been ranked i n descending order of magnitude of k. The entire group was then s p l i t i n half and average values were computed for each of the factors tabulated with respect to the values of -k. It i s apparent that there i s a tendency for the smaller values of k to correspond to r e l a t i v e l y small values of -k. This corresponds to the concept that animals which grow slowly;/ i n the f i r s t phase tend to show a r e l a t i v e l y low rate of decline i n growth rate i n the second phase. However, i t i s also apparent that some ind i v i d u a l s such as number 32L and 59L grew at second phase rates which tend to correspond to higher values of k. Thus, for one reason or another, some ind i v i d u a l s tended to grow at a less rapid rate i n phase two than would be expected from.their phase one values, and conversely some individ u a l s may not have grown at the maximum possible rate i n phase one, but were able 89 to compensate by growing r e l a t i v e l y more rapidly i n phase two. Table IX. Cha r a c t e r i s t i c s of growth patterns of i n d i v i d u a l high plane male deer of four races arranged i n descending order of magnitude of the value of k. Weaning I n f l e c t i o n Maturity kxlOO -kxlOO Age 1 Wt.2 Period Wt.2 Age 1 Wt.2 Age 1 90 1.8645 .2707 43 20.0 18 42. 5 87 295 5. 87 30 1.8057 . 1044 57 14.0 20 58. 0 133 230 13. 86 94 1.6604 42 19.5 18 — • — — • -50 1.6513 .2224 68 19.0 46 42. 0 110 215 6. 65 92 1.6412 . 1919 52 25.0 15 84. 0 122 343 : 8. 25 51 1.6042 . 1112 66 15.0 9 44. 0 130 270 13. 70 61 1.4816 _ _ _ 70 21.0 48 _ _ , _ _ _ _ — mm , _ 55 1.4709 .0959 66 20.5 37 48. 0 123 270 15. 76 32 1.4167 . 1728 59 16 .5 16 38. 0 114 290 9. 06 38 1.4106 .1084 30 17.0 61. 0 123 340 14. 05 25 1.1998 . 1293 52 14.0 24 79. 0 196 215 10. 93 59 1.1662 .1631 67 17.5 46 39. 0 133 180 8. 66 1 1.1226 . 1239 66 25.5 17 72. 0 159 275 12. 17 Averages Gp. 1 1.7046 . 1800 54. 7 18.8 21.0 54. 1 116.4 270.6 9. 67 Gp. 2 1.3241 . 1322 58. 6 18.9 31.3 56. 2 141.3 261.7 11. 85 1 In days 2 Weight in pounds In addition to environmental factors, genetic pat-terns may dictate that growth take place r e l a t i v e l y slowly i n the f i r s t phase and more rapidly i n the second. One would expect that genetic differences would be e f f e c t i v e i n causing some ind i v i d u a l s to grow i n the second phase at lower rates than one would expect from their f i r s t phase rates, when raised i n a constant n u t r i t i o n a l environment. If the experi-mental male deer are ranked i n a r e l a t i v e order of magnitude of f i r s t phase growth rates (k), i t i s apparent that four 90] in d i v i d u a l s , 30L, 38L, 51L, and 55L change their r e l a t i v e position to one another by d i s p l a y i n g . r e l a t i v e l y low -k v a l -ues (Table IX). If these four indi v i d u a l s are removed from the series, then i n the remaining series, numbers 25L and 59L show reversed positions with respect to -k. If number 59L i s selected for removal from t h i s series as representing an animal which grew more slowly i n the f i r s t phase than one would expect from i t s position r e l a t i v e to the value of -k, then the age at ultimate si z e forms a series which increases with decreasing values of k and -k as shown i n Table Xa. If, on the other hand, xk i s considered that number 25L grew r e l a t i v e l y more rapidly i n phase two than expected, then number 59L does not f i t i n the age-at-maturity series (Table Xb). It i s concluded that for some reason, No. 59L was the in d i v i d u a l which compensated and thus does not f i t the series. Table IX shows that age-at-weaning and weaning-weight do not correspond to a decreasing order of magnitude i n growth rates (k). As was found by MacDonald (1958), no co r r e l a t i o n could be demonstrated between either age or weight at weaning and growth rate. S i m i l a r l y , Table IX shows that the weight at i n f l e c t i o n and the ultimate size do not correspond to decreasing values of k and -k. Both of these factors appear to be associated, as was shown previ-ously, with genetic differences i n r a c i a l o r i g i n , rather than with environmental factors. 91 Table Xa. Growth c h a r a c t e r i s t i c s of individuals arranged i n a descending series of both k and -k values. Weaning I n f l e c t i o n Maturity kxlOO -kxlOO Age 1 Wt.2 Period Wt.2 Age 1 Wt.2 Age 1 90 1.8645 . 2701 43 20.0 18 42 87 295 5 .87 50 1.6513 .2224 68 19.0 46 42 110 215 6 .65 92 1.6412 . 1919 52 25.0 ; 15 84 122 343 8 .25 c.-32 1.4167 . 1728 59 16.5 16 38 114 290 9 .06 25 ; 1.1998 .1293 52 14.0 24 79 196 215 10 .93 1 1.1226 . 1239 66 25.5 17 72 159 275 12 .17 Table Xb. As in Xa 1 but with deer No. 59L substituted : for deer No. 25L. 90 1.8645 .2701 43 20.0 18 42 87 295 5. 87 50 1.6513 .2224 68 19.0 46 42 110 215 6. 65 92 1.6412 . 1919 52 25.0 15 84 122 343 8. 25 32 1.4167 . 1728 59 16.5 16 38 114 290 9. 06 59 1.1662 . 1631 67 17.5 46 39 133 180 8. 66 1 1.1226 . 1239 66 25.5 17 72 159 275 12. 17 1 In days 2 Weight i n pounds The length of the weaning period may a f f e c t the early growth rates and the age of i n f l e c t i o n as indicated by sub-group averages i n Table IX. However, i t i s unlikely that the differences shown are s i g n i f i c a n t . Removal of i n d i v i d -uals which may have shown compensatory growth from the series, further indicates that, the range of weaning periods had no e f f e c t upon the rate of growth, (see Table Xa). Undoubtedly, an extended weaning period could cause reduced growth rates i n the f i r s t phase with a consequent extension of the age of i n f l e c t i o n , but reasonably short weaning periods appear to have l i t t l e or no e f f e c t on the course of e f f e c t i v e growth. 92 Tables IX and X show that f i r s t phase growth rates are not related to the ultimate or mature weight. This i s i l l u s t r a t e d by the fact that a descending series of k values does not produce a si m i l a r series of values for weight-at-maturity. If the series i s rearranged on the basis of a descending order of -k values, the same condition holds true (Table XI). This simply suggests that some animals, though ultimately small, are capable of r e l a t i v e l y rapid growth i n the f i r s t phase. The converse must also be true and tends to indicate that ultimate size i s probably a better i n d i c a t i o n of genetic differences than are rates of growth. This i s p a r t i c u l a r l y true with respect to the Vancouver Island and Alaskan B l a c k - t a i l e d deer. Sub-group differences i n the age when ultimate size i s reached, indicate that a possible c o r r e l a t i o n exists between the rate of f i r s t phase growth and age at maturity, (Table IX). Removal of i n d i v i d u a l s from the series which are suspected of demonstrating a form of growth compensation, leads to a stronger c o r r e l a t i o n between these two growth characters, as i s shown in Table Xa. This suggests that early growth rates have a greater bearing on the age at which mature weight i s reached, than they do upon the magni-tude of the mature weight i t s e l f . Rearrangement of the entire series shown i n Table IX on the basis of a descending order of second phase growth rates, as shown in Table XI, further i l l u s t r a t e s t h i s point, and indicates a stronger 93 cor r e l a t i o n between -k and age-at-maturity. Fig. 15 shows that a plot of age-at-maturity versus growth rate r e s u l t s i n a curve, suggesting that r e l a t i v e l y small increases i n growth rate i n both the f i r s t and second phase markedly decreases the time required for the animal to reach mature siz e , regardless of the magnitude of the mature siz e , and genetic o r i g i n of the in d i v i d u a l s . Table XI. Charact e r i s t i c s of growth patterns of i n d i v i d u a l male deer of four races arranged i n descending order of magnitude of the value of -k. Weaning I n f l e c t i o n Maturity Deer No. -kxlOO Age1 Wt.2 Period Wt.2 Age 1 Wt. 2 Age 1 90 .2701 43 20.0 18. r", 42.5 87 295 5.87 50 .2224 68 19.0 46 42.0 110 215 6.65 92 . 1919 52 25.0 15 84.0 122 343 8.25 32 . 1728 59 16.5 16 38.0 114 290 9.06 59 . 1631 67 17.5 46 39.0 133 180 8.66 25 .1293 52 14.0 24 79.0 196 215 10.93 1 . 1239 66 25.5 17 72.0 159 275 12.17 51 . 1112 66 15.0 9 44.0 130 270 13.70 38 . 1084 30 17.0 61.0 123 340 14.50 30 . 1044 57 14.0 20 58.0 133 230 13.86 55 .0959 66 20.5 37 48.0 123 270 15.76 Averages Gp. 1 .2041 57.8 19.6 28.2 49.1 113.2 264.6 7.70 Gp.2 . 1122 56.2 17.6 21.4 60.3 144.0 266.6 13.49 1 In days 2 Weight i n pounds If the data for indivi d u a l s which were removed from the series i n Table IX are arranged i n descending order of magnitude of the f i r s t phase growth rate, i t i s evident, as before, that the c h a r a c t e r i s t i c s shown do not produce a 9 4 Fig. 15. The relationship between age at W« and growth rates r-20 H 5 *\ h 5 •\ Second phase HO First \ N s phase >^  v . First phase growth rates (k) 0 50 100 150 2 00 2-50 300 i i i i i 1 1 0 05 010 015 020 0-25 0-30 Second phase growth rates (— k x 100) 95 series by showing either increasing or decreasing orders of magnitude (Table XII). It i s noticeable, however, that this group i s composed of a l l but one of each of the Vancouver Island and Alaskan races. This tends to indicate that these two races are genet i c a l l y similar and that the true growth pattern of these races consists of a moderate f i r s t phase growth rate and a r e l a t i v e l y high second phase growth rate. The i n f l e c t i o n weight and i n f l e c t i o n age of a l l f i v e animals i n t h i s group are sim i l a r , thereby further indicating the s i m i l a r i t y of their genetic growth patterns i n a given n u t r i -t i o n a l environment. Rearrangement of thi s group i n a des-cending order of the second phase growth rate (-k) brings to l i g h t no new relationships, but tends to further substanti-ate the rel a t i o n s h i p of the rate of growth with the age at which the ultimate weight (A) i s reached, as shown by the s i m i l a r i t y of order i n -k values and age-at-maturity. Table X l l a . Characteristics;of growth patterns of deer demonstrating r e l a t i v e l y high phase two; growth rates arranged i n descending order of magnitude of the instantaneous r e l a t i v e growth rate, k. Weaning I n f l e c t i o n Maturity Deer No. kxlOO -kxlOO Age 1 Wt. 2 Period Wt.2 Agel Wt.2 Age1 30 1.8057 . 1044 57 14. 0 20 42 133 230 13.86 51 1.6042 .1112 66 15. 0 9 44 130 270 13.70 55 1.4709 .0959 66 20. 5 37 48 123 270 15.76 38 1.4106 . 1084 30 17. 0 — 61 123 340 14.80 59 1.1662 .1631 67 17. 5 46 . 39 133 180 8.66 96 Table X l l b . As i n XIa but arranged i n descending order of the second phase growth rates, -k. Deer No. kxlOO -kxlOO Age 1 Weaning Wt.2 Period I n f l e c t i o n Wt.2 Age 1 Maturity Wt.2 Agel 59 .1631 67 17.5 46 39 133 180 8.66 51 .1112 66 15.0 9 44 130 270 13.70 38 .1084 30 17.0 — 61 123 340 14.80 30 .1044 57 14.0 20 42 133 230 13.86 55 .0959 66 20.5 37 48 123 270 15.76 ± In days 2 Weight i n pounds THE INSTANTANEOUS RELATIVE GROWTH RATES OF HIGH PLANE FEMALE DEER OF FOUR RACES As was shown previously, growth patterns of high plane female deer followed the same general pattern as shown for high plane bucks. However, the magnitude of weight changes was greatly reduced i n the females. L i t t l e can be gained from comparisons of r a c i a l growth patterns of female deer since only a few animals were available for study. However, i t i s apparent that the lowest growth rate occurred i n the single C a l i f o r n i a n Black-t a i l i n both phases of growth (Table XIII). Slow growth was also demonstrable i n the high plane male deer of t h i s race. Add i t i o n a l l y , the Mule deer doe (No. 97) grew faster than any of the others i n the second phase of e f f e c t i v e growth, while i t grew at approximately the same rate as the others in the f i r s t phase. This pattern was also demonstrated for the high plane Mule deer bucks. The Mule deer doe (No. 97) also possessed the highest estimated ultimate s i z e of a l l deer with the exception of one Vancouver Island doe (No. 56). The l a t t e r animal i s not thought to be tr u l y representative of the Vancouver Island race because the growth pattern d i f -fered from a l l other high plane deer by continuing to increase throughout summer and winter at an almost constant rate i n the second and t h i r d years. This pattern i s sugges-tive of an animal which reached puberty but which may have thereafter suffered some ovarian malfunction preventing ovarian hormones from i n t e r f e r i n g with the course of growth. Table XIII. Instantaneous r e l a t i v e growth rates of high plane female deer of four r a c i a l o r i g i n s (k x 100) and (-fc.x 100). Race No. k x 100 -k x 100 A C a l i f o r n i a 21L 1.3733 0.2330 112.5 Alaska 35L 1.5448 0.3198 130.0 37L 1.8742 0.2587 142.0 Vancouver Island 53L 1.8372 0.2121 135.0 56L 1.5393 0.1323* 190.0* Mule Deer 97L 1.5972 0.4181 190.0 * Growth curve of th i s deer d i f f e r s from a l l others and i s , therefore, considered abnormal. In Table XIV, some c h a r a c t e r i s t i c s of the growth patterns of female high plane deer are shown i n descending order of magnitude of the values of k. As was s i m i l a r l y demonstrated for the males, ranking on the basis of the values of k does not show a rel a t i o n s h i p between the rate of f i r s t and second phase growth, nor between k and age-at-weaning, weight-at-weaning, length of the weaning period, 98 i n f l e c t i o n weight, i n f l e c t i o n age or ultimate s i z e . In addition, the re l a t i o n s h i p between k and age-at-maturity i s not apparent i n the growth patterns of females. However, i f the does are ranked by decreasing order of magnitude of the second phase growth rates (-k) a strong c o r r e l a t i o n appears to ex i s t , as was shown i n male growth c h a r a c t e r i s t i c s . No corr e l a t i o n was found between -k and ultimate size (A) indicating that the rate of decline i n growth rate i s not related to mature si z e . Table XIV. Charact e r i s t i c s of growth patterns of i n d i v i d u a l high plane female deer of four r a c i a l o r i g i n s , arranged i n descending order of the value of k. Weaning I n f l e c t i o n Maturity Deer No. kxlOO -kxlOO Age1 Wt. 2 Period wt. 2 Age 1 Wt.2 Age 1 37 1.8742 .2587 46 16. 0 19 34 90 142 5.16 53 1.8372 .2121 58 19. 0 13 45 105 135 6.07 97 1.5972 .4181 47 20. 0 20 36 80 190 3.48 35 1.5448 .3198 46 15. 5 20 35 100 130 4.13 56 1.5393 . 1323* 57 20. 5 30 53 120 190* 10.50* 21 1.3733 .2330 35 15. 0 12 55 130 112 5.11 Av. 1.6277 .2623 48.1 17. 7 19 43 104.2 142 4.79 x In days 2 Weight i n pounds * The growth curve of this deer i n phase 2 d i f f e r e d from a l l others and i s , therefore, considered abnormal. Comparisons between c h a r a c t e r i s t i c s of the growth patterns of high plane males and females indicates that the females tend to grow more rapidly i n the s e l f - a c c e l e r a t i n g phase of growth. Differences i n growth rate (k) group means composed of a l l four races for males and females were not 99 found to d i f f e r s i g n i f i c a n t l y because of the v a r i a b i l i t y introduced by lumping the data from a l l four races. How-ever, by comparing the pre-pubertal growth rates of females within each race with the data for the males of the same race i t was apparent that the females frequently grew more rapidly than the males. Conversely, the rate of decline i n growth rate (-k) was more rapid i n the females than i n the males i n a l l four races. Moreover, the age-at-weaning, i n f l e c t i o n age and age-at-maturity indicate that the female tends to mature faster and at smaller body weights than do the males. Larger sample sizes are required to ascertain the degree of sig n i f i c a n c e of the apparent differences between sexes. THE INSTANTANEOUS RELATIVE GROWTH RATES OF FOUR RACES OF MALE BLACK-TAILED DEER, ON LOW PLANE FEEDING It was demonstrated previously that points could be found on low plane growth curves which would permit the construction of curves si m i l a r i n a l l respects to those of the high plane deer. However, i n some deer on low plane, the exact position of the peaks, corresponding to the calcu-lated plane and the onset of rut, are obscure because of infrequent and ir r e g u l a r weighings. Moreover, even though the low plane deer were fed above the calculated l e v e l during the winter, the o v e r a l l plane was much lower than that fed to the high plane deer. For these reasons, the e f f e c t i v e 100 curves of growth for low plane deer were constructed through peak values, i r r e s p e c t i v e of the commencement of rut. The values of k, -k, and A, shown in Table XV, therefore, repre-sent the course of growth corresponding to the o v e r a l l low plane of n u t r i t i o n • Table XV. The instantaneous r e l a t i v e growth rates of low plane male deer of four races, in the f i r s t and second phases of g rowth. Race No. k x 100 -k x 100 A C a l i f o r n i a 19L 1.4209 0.1612 125 22L 0.6931 0.2174 126 Av. L . P . c f 1.0570 0.1893 125. 5 Av. H.P.<? 1.1612 0.1266 245. 0 Alaska 33L 1.2870 0.1632 140 34L 0.7724 0.1998 120 36L 0.1451 150 Av. L.P.> 0.8692 0.1694 136. 6 Av. H.P . c f 1.5443 0.1285 287. 0 Vancouver Island 58L 0.8554 0.1524 125 Av. H.P.5- 1.4748 0.1482 234. 0 Mule Deer 104L 0.8649 0.1418 170 105L 0.7821 0.1251 190 Av. L.P.J 0.8235 0.1335 180. 0 Av. H.P.<? 1.7220 0.2215 319. 0 The plane of n u t r i t i o n during the suckling period was standard for both high and low plane deer so that the ef f e c t of high and low plane feeding regimes does not appear during this period. For this reason, growth rates for the f i r s t phase of e f f e c t i v e growth were computed from the age of weaning to the approximate i n f l e c t i o n point. Thus the values of k i n low plane males do not have the r e l i a b i l i t y shown by high plane deer because the curve f i t s only a very 101 b r i e f period. Additionally, i n deer Nos. 19 and 33, t h i s portion of the curve i s r e l a t i v e l y steep, possibly as a r e s u l t of growth compensation and therefore, i s not thought to t r u l y represent the early low plane growth pattern (Table XV). Fig. 16 shows that the second phase pattern of e f f e c t i v e growth and the equation W = A - Be~ k t f i t s most of the data during pre-pubertal growth with a reasonable degree of accuracy. It i s therefore suggested that the low plane of n u t r i t i o n caused the growth pattern to change i n such a manner that the equation W = Ae k* does not represent the course of growth. This i n turn suggests that at cert a i n low leve l s of n u t r i t i o n , growth can no longer be proportional to the mass of the growing i n d i v i d u a l , but i s at a l l times proportional to the ultimate size which i s in turn related to environmental opportunity. Thus on a low plane of n u t r i -tion, growth i s proportional to the available food supply, throughout the entire course of growth. Hence genetic d i f -ferences are masked by environmental factors. This fact i s demonstrated by the s i m i l a r i t i e s i n the values of k and -k for i n d i v i d u a l s and races shown i n Table XV. The s i m i l a r i t i e s i n the values of k and -k for the d i f f e r e n t races, also indicates that no major d i f f e r -ences i n the e f f i c i e n c y of the growth process i s demonstra-ble. If indiv i d u a l s of a given race were capable of more Fig. 16. The equation W=A —Be fitted from the second phase data and extrapolated through the prepubertal phase for low plane deer 19 L. 100 200 300 400 500 600 700 800 ' i 1 1 » « i i Age in days 10 3 e f f i c i e n t use of their n u t r i t i o n a l environment, one would expect that the rate of growth would be increased propor-tionately to the increased degree of e f f i c i e n c y . Such a factor may be instrumental i n causing the v a r i a t i o n between individ u a l s i n the low plane group, but no evidence exists in the small number of animals available that such increased e f f i c i e n c y i s a r a c i a l c h a r a c t e r i s t i c . However, t h i s does not imply that differences i n the e f f i c i e n c y of use of their natural ranges could not e x i s t . Environmental factors such as the r e l a t i v e abundance, and quality of natural foods undoubtedly leads to differences i n the e f f i c i e n c y of production which would be demonstrable i n terms of growth, ir r e s p e c t i v e of genetic differences. It i s , however, important to note that the four races show similar inherent e f f i c i e n c y with respect to a standard quantity and quality of food. Differences between races with regards to the calculated ultimate weight (A) indicate that the low plane of n u t r i t i o n does a l t e r ultimate s i z e as compared to high plane values, but that r a c i a l differences are not completely masked (Table XV). This suggests, p a r t i c u l a r l y i n the case of the Mule deer, that the impetus to grow to a c e r t a i n size, i s a genetic c h a r a c t e r i s t i c which i s weight-specific. Thus even though the rates of growth are similar the temporal rate at which growth declines, i s not limited i n the same degree. For t h i s reason, the calculated ultimate 104 sizes of low plane bucks shows a s i m i l a r r e l a t i o n s h i p between races as was shown for high plane males. The Mule deer would appear to be gen e t i c a l l y the largest race, followed by the Sitka deer and the Columbian B l a c k - t a i l , i r r e s p e c t i v e of whether the l a t t e r originated i n C a l i f o r n i a or Vancouver Island. Comparisons of the values of k between high and low plane males shows that the low plane group grew at approximately half the rate shown by the high plane animals. Si m i l a r l y , i n the second phase, the rate of decline i n growth rate (-k) was more rapid i n the low plane group but the rate of decline i s related to the reduced value of A. It i s therefore apparent that to compare growth rates of groups from d i f f e r e n t environments, one must measure the rate at which the r a c i a l maximum size i s reached, rather than the rate at which the environmentally determined ultimate size i s approached. In order to u t i l i z e t h i s method, i t i s neces-sary to e s t a b l i s h a r a c i a l average for A which represents the genetic maximum. In the present experiment, i n s u f f i c i e n t numbers of animals prevent such treatment. However, i f i t i s assumed that the average value of "A" for the high plane male Ca l i f o r n i a n B l a c k - t a i l s represents the average r a c i a l maximum of 245 lbs, the data for low plane deer No. 19L represents a reasonably straight l i n e when A - W i s plotted against age on semilog paper. This indicates that the method can be used since the equation W = A - Be - k "k may be f i t t e d to 105 the data only i f this requirement i s f u l f i l l e d . By t h i s method the value of -k for No. 19L i s reduced from .00161 to .000497 with respect to an ultimate size of 245 lbs. The l a t t e r value, therefore, represents the rate of decline in growth as the animal approaches the genetic maximum for the race. In t h i s form, the growth rate (-k) may be used to describe differences i n growth attr i b u t a b l e to one or more environmental factors. Otherwise the rate of decline i n growth shown by low plane males can be evaluated with res-pect to the plane of n u t r i t i o n only i f the low value of A i s also taken into account. It should be noted that the above method permits one to describe the course of low plane growth with respect to a single value, -k, but at the same time the calculated curve i s somewhat flattened. This means that the advantage gained i n the comparison of i n d i v i d u a l s and groups, leads to a reduction i n the a b i l i t y of the curve to describe the actual course of e f f e c t i v e growth. For example, the calcu-lated weight at 700 days of age i n No. 19L i s 87.0 lbs for a value of 125 lbs for A, while calculated weight for an A-value of 245 lbs i s 85.0 lbs. Si m i l a r l y there i s a d i f f e r -ence of 4.3 lbs between the calculated values at 400 days of age. For t h i s reason, the c a l c u l a t i o n of -k for the description of the curve of growth must be related to the actual ultimate size of the animal. Nevertheless, compari-sons of indiv i d u a l s and groups with respect to environmental 106 differences can be based on the ultimate r a c i a l size under optimal conditions without destroying the a b i l i t y of the equation to represent the course of e f f e c t i v e growth. 107 PART III . PATTERNS OF LINEAR GROWTH FOR INDIVIDUAL DEER OF EACH RACE GROWTH CURVES OF SOME LINEAR BODY DIMENSIONS Growth i n weight and physical maturity i s frequen-t l y accompanied by changes i n body conformation. In ungu-lates, change i n form i s gradual as i t r e s u l t s from d i f f e r -ent parts of the body and d i f f e r e n t tissues growing at d i f -ferent, though proportional rates. Hamond (1932), i n his work with domestic sheep, found that age, breed, sex and n u t r i t i o n a l conditions affected the r e l a t i v e development of di f f e r e n t j o i n t s and tissues. McMeekan (1940a), i n his study of growth and development i n the pig, added further proof to Hammond's theories and demonstrated that gradients of growth rates e x i s t i n various parts of the body. He demonstrated that there was an anterior-posterior gradient from e a r l i e r to la t e r developing regions and that t h i s gradient p r e v a i l s within any one tissue. He also found that within each limb, there i s a ce n t r i p e t a l gradient of growth. McMeekan (1940b & c) and Pa'lsson and Verges (1952) demonstrated that the plane of n u t r i t i o n affects the growth of various parts of the body d i f f e r e n t l y with the r e s u l t that differences i n conformation were produced. Those parts of the body which were r e l a t i v e l y mature at b i r t h , were less affected by the plane of n u t r i t i o n than those which devel-oped l a t e r . Consequently, the head, neck, ears, legs and 108 body length were penalized r e l a t i v e l y less than body depth, l o i n and hind quarters by inadequate n u t r i t i o n . S i m i l a r l y , i t was shown that growth of s k e l e t a l elements was affected less by n u t r i t i o n a l inadequacies than were muscle and f a t . These findings led to the development of a theory of p r i o r i -t i e s for nutrients which was developed by Hammond (1950 8s 1952). McMeekan (1940b) demonstrated that external measurements on the body surface show the same relat i o n s h i p to the plane of n u t r i t i o n as do parts and tissues. However, due to their relationship to the skeleton, they show a proportionately smaller response to n u t r i t i o n than i n t e r n a l carcass measurements of muscle and f a t . He also showed that the influence of f l e s h cover reduces the value of certain external measurements as c r i t e r i a of the degree of s k e l e t a l development. Of the measurements used i n this study to depict changes i n body conformation i n deer, the chest g i r t h i s most seriously influenced by the development of non-skeletal tissues such as muscle and f a t . Consequently, the growth pattern of chest g i r t h tends to demonstrate the same seasonal fluctuations shown by growth curves of weight (Fig. 17). This occurs because chest g i r t h i s a measurement of volume rather than linear growth and i s therefore more clo s e l y associated with change i n weight than other t r u l y 109 80 70 j?60 c o u> c 0) E 50 40 o 0> 30 /o 20 10 width Fig. 17. The linear growth patterns of a high plane male Californian Black-tail (01L) 100 200 300 400 Age in days 500 1.10 li n e a r measurements. Fig. 17 also shows an apparent c o r r e l a t i o n with seasonal weight fluctuations i n the f i r s t winter growth break for the measurement of height-at-withers. However, thi s r e l a t i o n s h i p i s not nearly as pronounced i n other deer, as shown by Figs. 18 to 20. It i s not l i k e l y that the development of f a t and muscle influences the height-at-withers measurement to any large degree and for th i s reason the apparent re l a t i o n s h i p i n F i g . 17 i s believed to be related to measurement error and the form of the curve. The remainder of the li n e a r measurements show no co r r e l a t i o n with the cessation of growth during the f i r s t winter. Since the skeleton has been shown to have a higher p r i o r i t y for nutrients than either muscle or f a t , the s k e l e t a l elements measured, show continuous development. Furthermore, because the length of s k e l e t a l elements does not undergo negative growth, as does weight, the growth of li n e a r measurements i s thought to depict physiological development much better than weight/growth. The growth curves of li n e a r measurements i n deer demonstrate no s e l f - a c c e l e r a t i n g phase as was shown for growth i n weight. Instead, growth i n linear dimensions appears to reach a maximum very shortly after b i r t h and to decline at a constant and rapid rate, as shown by the high plane males of the four races (Figs. 17 to 20). I t i s -I I I I L— 100 200 300 400 500 Age in days 112 (30 L) —i 1 i i I 100 200 300 400 500 Age in days 1 1 3 100 200 300 400 Age in days 500 114 noticeable also, that the shape of the curves described by the growth of each linear element are s i m i l a r , thereby i l l u s t r a t i n g that a proportionality exists between a l l measurements. Brody (1945) stated that linear growth tends to proceed i n an arithmetic fashion p r i o r to puberty and the point of i n f l e c t i o n i n weight growth and to grow exponenti-a l l y beyond t h i s point. The curves shown for height-at-withers and for chest-girth i n Figs. 17 - 20 may be f i t t e d equally well i n the p r e - i n f l e c t i o n portion by a straight l i n e or by a curve. However, measurement errors preclude the p o s s i b i l i t y of testing which form i s most suitable. Furthermore, i t i s rea d i l y apparent that a li n e a r r e l a t i o n -ship would not f i t the remaining measurements for the pre-i n f l e c t i o n period. For th i s reason, the same exponential curve was used for a l l measurements over the entire period. The resultant f i t indicates that t h i s procedure was suitable for analysis. SIZE AT BIRTH IN RELATION TO THE FINITE SIZE FOR VARIOUS LINEAR MEASUREMENTS Comparisons between lin e a r measurements can be made with the parameters established for the equation L = A - B e - k t . The curves were extrapolated to obtain a " b i r t h s i z e " for each of the linear elements (L where t = 0) which can then be compared to f i n i t e size (A) i n order to 115 depict the r e l a t i v e proportions achieved at b i r t h . The high plane males of the Vancouver Island race were used for t h i s purpose because t h i s group contained the largest number of animals and because the high plane of n u t r i t i o n was thought to evoke the expression of ge n e t i c a l l y controlled r e l a t i o n -ships . Palsson and Verges (1952) have shown that of a l l the organs of the body, the brain i s the e a r l i e s t developing and as a r e s u l t , the proportions of the s k u l l mature at an early stage of development. Table XVI shows th i s r e l a t i o n -ship to be true for deer since the head length and head width reached the greatest degree of development at b i r t h of a l l the measurements used i n this experiment. The s i g n i f i -cantly smaller development of head length i s attributable to a r e l a t i v e immaturity of the nasal and maxillar bones. Table XVI. Size of each li n e a r element achieved at b i r t h expressed as a percentage of the asymptotic values (A) for high plane males of the Vancouver Island race • Deer Chest Hip Height @ Hind Leg Head Head No. Girt h Width Withers Length Length Width 50 30.6 37.9 40.3 48.7 48.5 53.0 51 25.9 34. 1 34.9 45.3 45.2 51.7 55 33.8 44.3 42.4 51.3 55.1 55.4 59 32.1 39.0 42.7 50.1 53.3 58.7 61 30.9 38.6 40.5 49.7 49.3 43.6 Av. 30.6 38.8 40.1 49.0 50.3 54.5 S.D. 2.94 * 3.65 3.13 * 2.28 3.95 2.71 * Means not s i g n i f i c a n t l y d i f f e r e n t at the 5% l e v e l . A l l means not joined by a l i n e are s i g n i f i c a n t l y d i f f e r e n t at the 5% l e v e l . (Duncan's New Multipe Range Test) 116 The s i g n i f i c a n t difference between the percentage achieved at b i r t h for the hind leg length and the head length and the greater maturity of head and hind leg measurements are i n keeping with the findings of Palsson and Verges (1952) who have shown that there i s an increas-ing growth rate from the head and feet to the l o i n region with the feet and head growing least i n absolute size after b i r t h (see also Lewall and Cowan, 1963). Height-at-withers, hip width and chest g i r t h are the least developed at b i r t h of the six measurements. Chest g i r t h i s the least mature of a l l because of i t s dependence upon body volume and i s thereby related to the late-maturing weight. Furthermore, Palsson and Verges (loc. c i t . ) have found that the r i b s , which profoundly a f f e c t chest g i r t h , are the l a t e s t maturing bones of the body. The i n s i g n i f i c a n t difference between the size of hip width and height-at-withers attained at b i r t h indicates a close correspondance between height and breadth i n the body as a whole. The chest g i r t h , which i s related to both height and breadth d i f f e r s s i g n i f i c a n t l y i n the percentage of i t s f i n i t e s i z e achieved at b i r t h because of i t s d i r e c t r e l a t i o n s h i p to body weight. Palsson and Verges (loc. c i t . ) stated that those dimensions which have achieved a large percentage of their growth at b i r t h tend to show the most rapid rates of growth 117 immediately after b i r t h . The lack of data at very early ages for the deer used i n this experiment does not permit examination of th i s concept. Instead, l a t e r , absolute, growth rates were most rapid i n those linear elements which reached the smallest proportion of their f i n i t e size at b i r t h , as shown i n Figs. 17 to 20. Such a finding i s to be expected since those portions which have been>. depressed i n interuterine growth must grow rapidly after b i r t h i n order to compensate for the r e s t r i c t e d interuterine growth gradients. RATES OF GROWTH OF CERTAIN LINEAR ELEMENTS The equation L = A - B e - k t does not permit growth rate to be expressed d i r e c t l y because -k represents the rate of decline i n growth rate r e l a t i v e to the f i n i t e s i z e . However, the equation can be used to compute f i t t e d values of L at given time periods and these values may i n turn be used to evaluate growth rate d i r e c t l y . The value k* shown in Table XVII was derived by the Walford method (1945) and represents growth rate expressed as the rate at which mature size i s reached. Values of L were obtained for ages t = 0, 50 and 100 so that k* was computed as: k = LtiQQ ~ Lt5Q Lt50 - L t o In t h i s treatment, the larger the value of k*, the more slowly the dimension growth towards i t mature s i z e . LIS An analysis of variance indicates no s i g n i f i c a n t d i f f e r -ences between the mean values for each measurement. How-ever, the small values of N required to estimate within 5% of the mean 95 times out of 100 suggest that adequate sample sizes must reveal some differences i n the rates at which d i f f e r e n t l i n e a r measurements approach mature si z e . Table XVII. The rate of approach;to mature size expressed by the Walford method k* = L-t+3 - Lt+2 for f i t -Lt+2 ~ L-t+l ted values of L for Vancouver Island high plane male deer. Deer Height @ Chest Hind Leg Head Head Hip No. Withers Girt h Length Length Width Width 50 .735 .771 .746 .788 .833 .686 51 .724 .791 . 818 .718 .688 .719 55 .735 . 798 .774 .727 .645 .741 59 .778 .816 .800 .815 .696 .800 61 .715 .864 .697 .757 .857 .767 x l .737 .808 .767 .761 .744 .743 S* .024 .070 .095 .081 .094 .087 N 2.8 19.8 40.5 29.9 42.2 36.3 N i s the sample size required to estimate within 5% of the mean 95 times out of 100. 1 Analysis of variance indicates no s i g n i f i c a n t differences e x i s t between the means at the 5% l e v e l . * S i s the standard deviation. The mean rates of decline i n growth rate (-k) for each li n e a r measurement a r e ; i h s i ^ a ^ ^ O | i ^ ^ ^ ^ ^ ^ ^ h t from each other (Table XVIII). Thus while there appear to be differences i n absolute rates of growth, as depicted i n Figs. 17 to 20, the rates of decline i n the r e l a t i v e growth rate behave i n a similar fashion to the rate of approach 119 to maturity. These findings indicate that the growth response of the various body parts measured, i s subject to an o v e r a l l c o n t r o l l i n g mechanism which i n turn i s related to a genetic maximum: size on a high n u t r i t i o n a l plane. Furthermore, because there are no s i g n i f i c a n t differences i n the growth rate of the various elements or i n the rate of decline i n growth rate, the curves of growth for each element are very s i m i l a r i n shape and consequently no marked changes i n form are apparent. Table XVIII. The rate of decline i n growth rate of Van-couver Island high plane male deer for each lin e a r measurement expressed as -k x 100 derived from the equation L = A - Be-kt. Deer Height @ Chest Hind Leg Head Head Hip No. Withers G i r t h Length Length Width Width 50 .636 .519 .637 .458 .350 .736 51 .634 .478 .558 .569 . 790 .599 55 ,615 .431 .552 .648 .812 .644 59 .520 .371 .519 .479 .643 .336 61 .591 .309 .692 .610 .317 .570 X 1 .599 .422 .592 .553 .582 .577 S* .047 .083 .071 .082 .236 . 148 N 16.2 102.3 38 4 0 58.1 434.6 174.0 N i s the sample size required to estimate within 5% of the mean 95 times out of 100. 1 Analysis of variance indicates no s i g n i f i c a n t differences ex i s t between the means at,the 5% l e v e l . * S i s the standard deviation. Attempts were made to determine whether the rate of growth (k*) and the rate of decline i n growth rate within each measurement were dependent upon the size at b i r t h , or the size at b i r t h expressed as a percentage of 120 the computed f i n i t e size A. Very low c o r r e l a t i o n coef-f i c i e n t s calculated for each measurement showed that no such relationships e x i s t . S i m i l a r l y , the rate of decline in growth rate and the rate of approach to mature size within each measurement are not correlated with the com-puted mature si z e A. The lack of c o r r e l a t i o n between growth rate and rate of decline i n growth rate with mature size or size at b i r t h r e l a t i v e to mature si z e within any one measurement for high plane Mule deer leads to the conclusion that on any given plane of n u t r i t i o n , the mature size i s i n t r i n s i -cally, fixed. At the same time the route by which mature size i s achieved may d i f f e r between in d i v i d u a l s . Thus di f f e r e n t animals may achieve the same order of magnitude in the f i n i t e size of a given measurement by growing rapidly i n the early periods with a rapid decline i n growth rate or by growing more slowly with a less rapid decline. A very good negative c o r r e l a t i o n ( r = 0.918) between k* and -k x 100 indicates that as growth rate increases there i s an increase i n curvature and consequently an increased rate of decline i n growth rate. The values of -k x 100 and k* for a l l six linear measurements produced a l i n e a r regression described by the equation Y.= 2.273 - 2.262X, where Y i s percentage decline in growth rate and X i s the rate of approach to mature 121 weight (k*) (Fig. 21). Thus i f the early growth rate i s known for three uniform periods of time an estimation can be made of the percentage decline i n growth for any of the line a r measurements used. It should be noted however, that each measurement should be tested separately with s u f f i c i e n t samples to determine i f the regression c o e f f i c i e n t s d i f f e r for each measurement. The sample size used i n thi s experi-ment i s too small to determine such differences. If how-ever, no d i s t i n c t i o n s e x i s t between measurements, the regression i n f e r s that the rate of decline i s correlated with growth rate i r r e s p e c t i v e of the measurement. Hence, those elements which achieve a r e l a t i v e l y slow rate of growth w i l l demonstrate a slow decline i n growth rate and conversely the growth of those elements which grow most rapidly after b i r t h w i l l decrease quickly. 0-9 Fig. 21. A regression of the rote of decline in growth (-k x 100) on the rate of growth (k*) for all six linear measurements "from high plane Vancouver Island males. 123 PART IV. GROUP COMPARISONS OF PARAMETERS DERIVED FROM GROWTH IN LINEAR SIZE THE EFFECT OF SEX UPON THE REGRESSION COEFFICIENTS AND CON-STANTS OF AGE RELATED LINEAR GROWTH Comparisons between the linear growth curves of males and females were made for the Vancouver Island race only because the numbers of animals available for study i n the other races were even smaller. I t i s expected however, that comparisons between high plane males and females of the other races would show sim i l a r differences to those demon-strated by the Vancouver Island race. Fig. 22, i n comparisons to Figs. 17 to 20, show that the form of the curves of growth for each of the six linear measurements does no d i f f e r between sexes. Chest g i r t h alone, as i n the males, shows a close correspondance with weight growth as can be seen by the reduced growth during the f i r s t winter period. Other measurements, as i n males, do not demonstrate a period of growth retardation during the f i r s t winter. Thus, i n both sexes, growth of linear s i z e , except i n chest g i r t h , tends to proceed con-tinuously from b i r t h to mature si z e . A comparison of Fig. 22 and Fig . 18 shows that the size attained by the females at 500 days i s , i n the case of each measurement, smaller than that shown by the male. In addition, i t i s noticeable that at 500 days of age, the P 124 / / -» 1 I l i__ 100 200 300 400 500 Age in days 125 growth curve of the female i s much f l a t t e r than that shown by the male. Thus, as i n the case of weight growth, i t would appear that the female attains itssmaller mature size e a r l i e r than does the male. Such differences may be due to sex related v a r i -ations which might already e x i s t at b i r t h . However, Table XIX shows that there are no s i g n i f i c a n t differences between sexes i n the estimated b i r t h size obtained from the regres-sion equations at t = 0. Thus, differences i n the rate of achievement of mature size and differences i n mature size i t s e l f are produced by sex differences i n the environment for growth as was discussed e a r l i e r with regard to weight. Table XIX. Comparisons of male and female high plane Vancou-ver Island deer with regard to b i r t h size, b i r t h s i z e expressed as a percentage of f i n i t e size and mature si z e . Average values were used for each measurement. , Estimated ... c. n Percentage of Mature Measurement 0. Mature Size „. . , . , „ _,. B i r t h Si^e ^ ^ Size Achieved <i| B i r t h Ht. ©withers 36.1 36.1 89.8 **81.9 40.1 * 44.1 Chest g i r t h 28.1 28.9 91.6 N S82.1 30.6 ** 35.1 Hind leg length 21.7 22.5 44.2***40.6 49.0****55.4 Head length 14.1 14.6 28.2 N S27.6 50.3 N S 52.9 Head width 11.8 11.3 21.7 * 18.9 54.5 ** 59.7 Hip width 7.3 7.3 18.9 N S17.5 38.8 N S 41.5 * S i g n i f i c a n t at P>0.1 ** " P>0.05 *** " P>0.01 **** " P>0.02 Table XIX also shows the average mature size of males and females obtained from regression analyses. The 126 values obtained for females are smaller i n each case than those shown for males and the differences shown are s t a t i s t i -c a l l y s i g n i f i c a n t . Because of the small sample sizes, s i g n i f i c a n c e at P>0.1 i s acceptable and i t i s suspected that small increases i n sample siz e would demonstrate s i g n i f i c a n t .differences:in those marked N S with the exception of the head length measurement. Because of the differences i n mature size between sexes and the lack of differences i n estimated size at b i r t h , the percentage of the mature size achieved at b i r t h shows similar s i g n i f i c a n t differences. However, the degree of sign i f i c a n c e i s increased by t h i s treatment as a r e s u l t of the reduction i n v a r i a b i l i t y . Thus the percentage of mature size achieved at b i r t h for chest g i r t h i s s i g n i f i c a n t l y d i f f e r e n t at P) 0.05. Since the mature size i s smaller for females for each measurement and because there are no d i f -ferences at b i r t h , the percentage of the mature siz e achieved at b i r t h i s greater for the females. The mature size of head length d i f f e r s from the other measurements i n the lack of sexual dimorphism. Table XX shows that there are also no s i g n i f i c a n t differences between sexes i n this measurement with,regard to the rate of growth (k*) or the rate of decline i n growth rate (-k x 100). Thus the "long-nosed doe" recognized i n the f i e l d i s the Table XX. Comparison between male and females with regard to average rates of lin e a r growth (k*) and the average rate of decline i n growth (-k x 100). Ht.@ W. Chest H.L. Hd. L. Hd. JT. Hip W. k* (<?) k* (9) X SD N X SD N .737 .024 2.8 .594-.052 31.0 P>.01 .808 .070 19.8 .767-1 .046 14.6 .767 .095 NS 40.5 . 677-.029 7.4 P>.05 . 761-.081 29.9 .774 .063 26.8 NS .7441 .094 42.2 .600-1 .079 70.2 P>.1 .743 .087 36.3 .681 .007 NS -kxlOO (<?) -kxlOO (?) X SD N X SD .599 .047 16.2 850J 266 N 396.6 .422i .083 P>0.1 102.3 .524 .118 205.5 .592 .071 NS 38.0 .795-1 .135 58.2 P>.05 .553 .082 58.1 .543J .116 184.9 .582 .236 NS 434.6 1.089 .227 176.0 .5771 .148 P>.01 174.0 .835* .035 P>0.1 ( 0 <1 128 r e s u l t of a sex difference i n the proportions between head length and head width. The apparent lack of allometry between these two measurements raises some inter e s t i n g questions with regard to the e f f e c t of the female physio-o l o g i c a l environment for growth and the response of those elements which comprise the head length measurement. The lack of a s i g n i f i c a n t difference i n growth rate k* for hip width, shown i n Table XX i s most l i k e l y due to the small sample size for the females. S i m i l a r l y , the lack of demonstrable differences for chest g i r t h are believed due to sample si z e . It i s l i k e l y that adequate samples would show s i g n i f i c a n t differences i n the rate of growth to maturity and the rate of decline i n growth rate for a l l measurements with the exception of head length. In a l l other cases, the female rate of growth and the rate of decline i n growth rate are more rapid (the smaller the value of k* the more quickly mature size i s reached). It i s of i n t e r e s t to note that the v a r i a b i l i t y i n growth rate i s less for the females i n a l l measurements except height-at-withers while the v a r i a b i l i t y i n the rate of decline i n growth rate i s more variable for the females than for the males. The reasons for these differences are not readily apparent but i t i s l i k e l y that the factors governing the rate of decline i n growth are more variable i n their e f f e c t i n the females. The same difference i n 129 v a r i a b i l i t y i s observed i n a regression of -k x 100 on k* as shown by a comparison of the differences i n the values for S b and S r on Figs. 21 and 23. In Fig. 23, Regression 1 includes the encircled points which diverge markedly from ,the remaining data. These two points represent height-at-withers and hind leg length for deer #62 which suffered a broken hip at an early age and consequently the divergence may be attributable to th i s fact. For this reason, the two encircled points were omitted for Regression 2 and i t i s believed that t h i s regression expresses the r e l a t i o n s h i p between.-k x 100 and k* for females more accurately than Regression 1. Compari-sons are therefore made between regressions Y d> = 2.273 -2.262X and Y? = 2.689 - 2.759X where Y i s the decline i n growth rate (-k x 100) and X i s the rate of growth expres-sed as the rate of approach to mature size (k*) . The increased slope i n the regression for females means that for a given rate of growth there tends to be a more rapid rate of decline i n growth than i s the case for males of the same race and the same plane of n u t r i t i o n . Consequently, estimations of -k x 100 from known values of k* must be treated separately for each sex. P h y s i o l o g i c a l l y , the difference between regres-sions suggest that i n females which grow most rapidly, there i s a correspondingly greater curb on growth rate than 130 0-6 0-7 0-8 0-9 10 Rate of growth (k*) Fig. 23. Regressions of the rate of decline in growth on the rate of growth for high plane females. 131 i s found i n males growing at the same rate. Therefore, the difference between the slopes i n the regressions for males and females must be attributable to the e f f e c t of the female sex hormones upon growth. For the measurements used i n t h i s experiment, the regressions of -k x 100 on k* for both males and females are highly s i g n i f i c a n t s t a t i s t i c a l l y . This suggests that instead;of demonstrating rates of decline i n correspondance to rates of growth which d i f f e r f o r each part, there i s an o v e r a l l control of the rate of decline for each animal which:is independent of the region, i n which the measurement i s made. Thus i n high plane male and female deer marked changes i n body form.did not occur and i t i s l i k e l y that changes i n r e l a t i v e proportions r e s u l t i n g from a low plane of n u t r i t i o n w i l l be small. THE EFFECT OF THE PLANE OF NUTRITION UPON THE GROWTH OF LINEAR MEASUREMENTS Differences i n form r e s u l t i n g from the d i f f e r e n -t i a l e f f e c t of the plane of n u t r i t i o n upon the growth of body parts have been demonstrated for pigs (McMeekan, 1940b) and for sheep (Palsson and Verges, 1952, Parts I and I I ) . Because deer are r e l a t i v e l y ^nature at b i r t h and because the foregoing has led to the conclusion that deer do not a l t e r i n form to any large degree, i t i s unlikely that the plane of n u t r i t i o n w i l l a f f e c t form to the same degree shown for 132 pigs and sheep. Fi g . 24 shows, as was noted i n the previous sec-tion, that growth i n weight through the f i r s t winter i s continuous with that of the f i r s t summer. Consequently, there i s no apparent winter break i n the curve of weight growth. Si m i l a r l y , there i s no break i n the growth curve for chest g i r t h as was noted i n the high plane males of the Vancouver Island race. The graph also shows, i n comparison to Fig. 18, that the form of the linear growth curves i s unaffected by the low plane of n u t r i t i o n . However, i t i s obvious that the rates of decline i n growth rate, shown by the degree of curvature of the growth curves, are reduced by the low plane of n u t r i t i o n . In t h i s way the plane of n u t r i t i o n appears to a f f e c t the course of linear growth i n deer. Table XXI shows the average derived values of A (estimated mature s i z e ) , -k x 100 (the rate of decline i n growth rate) and k* (the rate of growth) for both high and low plane males of the Vancouver Island race. The sample sizes for both planes of n u t r i t i o n are small but i t would appear that the low plane of n u t r i t i o n used i n t h i s experi-ment did not materially a f f e c t the mature size of any of the six li n e a r measurements except chest g i r t h (See Moulton, e_t a l . , 1921). Since chest g i r t h i s a measurement of volume and has been shown to be clo s e l y related to body 1 3 3 low plane male (58 L). * • • • • 100 200 300 400 500 Age in days Table XXI. The effect of a low plane of n u t r i t i o n on mature size (A) , rate of decline i n growth rate (-k x 1 0 0 ) and rate of growth (k*) demonstrated by the males of the Vancouver Island race. n H t . @ W . Chest H . L . H d . L . H d . W . H i p W . A ( H P <? ) 5 8 9 . 7 9 6 9 1 . 5 7 0 4 4 . 2 4 2 2 8 . 2 0 3 2 1 . 6 8 7 - 1 8 . 9 1 0 N S P X J . 0 2 N S N S N S N S A (LPc?) 2 8 6 . 4 5 3 7 1 . 8 2 7 4 5 . 5 6 3 2 7 . 0 4 6 1 9 . 0 6 9 1 7 . 7 4 9 -kxlOO ( H P o » ) 5 . 5 9 9 . 4 2 2 . 5 9 2 . 5 5 3 . 5 8 2 . 5 7 7 P > 0 . 0 2 N S P > 0 . 0 2 P > 0 . 0 5 N S N S -kxlOO ( L P < f ) 2 . 3 8 6 . 3 9 7 . 3 3 9 . 3 7 5 . 6 6 6 . 3 4 4 k* ( H P < ? ) 5 . 7 3 7 . 8 0 8 . 7 6 7 . 7 6 1 . 7 4 4 . 7 4 3 P > 0 . 0 5 N S N S P > 0 . 1 N S P > 0 . 1 k* (LPc?) 2 . 8 2 8 . 8 2 9 . 8 2 8 . 8 3 0 . 8 0 4 . 8 9 2 r-1 00 135 mass, the mature size i s s i g n i f i c a n t l y decreased by a low plane of n u t r i t i o n . The other measurements are not so affected and therefore indicate that the p r i o r i t y of n u t r i -ents for s k e l e t a l growth i s greater than for body mass, as was suggested by Hammond (1952). In addition, because the estimated mature size of a l l measurements, except chest g i r t h , i s not materially affected by the plane of n u t r i t i o n , the parameters possess genetic s i g n i f i c a n c e with regard to race. Consequently, the relationships between such parame-ters must also possess r a c i a l s t a b i l i t y as w i l l be examined l a t e r . The rates of decline i n growth (-k x 100) shown in Table XXI are, i n a l l cases, except head width, reduced by the low plane of n u t r i t i o n . The differences are s t a t i s -t i c a l l y s i g n i f i c a n t for height-at-withers, hind leg length and head length. Examination of the variance and the e f f e c t of small sample sizes suggests that larger samples would r e s u l t i n s i g n i f i c a n t differences i n a l l comparisons, with the possible exception of head width. This exception i s to be expected since i t was shown e a r l i e r that the head Width had achieved an average of 54% of i t s f i n i t e size at b i r t h and because the s k e l e t a l elements associated with the central nervous system must have a r e l a t i v e l y high p r i -o r i t y for nutrient supplies. Consequently, the low plane of n u t r i t i o n did not materially a f f e c t the rate of decline 136 i n the growth rate of t h i s element. Si m i l a r l y , the rate of growth (k*) shown for head width i s r e l a t i v e l y unaffected by the plane of n u t r i t i o n . The rates of growth (k*) for the remaining measurements show that the low plane of n u t r i t i o n s i g n i f i -cantly increased the values for height-at-withers, head length and hip width while no s i g n i f i c a n t differences were found for chest g i r t h , hind leg length and head width. Comparison of the s i g n i f i c a n t differences for k* and -k x 100 reveals that a r e l a t i v e l y small decrease i n the rate of growth r e s u l t s i n a r e l a t i v e l y large decrease i n the rate of decline i n growth rate. Thus, the rate of decline i n growth rate (-k x 100) appears to be more sensitive to the plane of n u t r i t i o n than i s the estimated growth rate k*. E a r l i e r , i t was shown that there were no s i g n i f i -cant differences i n the rate of decline i n growth rate of i n the rate of growth between each measurement for high plane males. Similarly, there are no s i g n i f i c a n t d i f f e r -ences between measurements for the low plane averages. This further indicates that a low plane of n u t r i t i o n does not a f f e c t the form of deer i n the same way as has been shown for pigs and sheep. Instead, the plane of n u t r i t i o n appears to depress the rates of growth of a l l parts measured to a similar degree with the possible exception of head width. Theoretical extrapolations r e s u l t i n the 137: conclusion that, insofar as the six measurements used here are concerned, there i s no evidence to support a d i f f e r -e n t i a l p r i o r i t y for growth in.deer following b i r t h . How-ever, i t w i l l be necessary to examine s k e l e t a l elements i n more d e t a i l before i t can be determined i f d i f f e r e n t i a l growth p r i o r i t i e s do ex i s t . A regression of -k x 100 on k* for the low plane Vancouver Island males when compared:with a sim i l a r regres-sion for high plane males (Fig. 25) shows that the slope i s affected by the plane of n u t r i t i o n . Consequently, for a given value of k* there i s a correspondingly smaller value of -k x 100 for the low plane deer of the same sex. Thus a prediction of the rate of decline i n growth rate must take into account the plane of n u t r i t i o n . However, in future analyses, the f i r s t approximations of the value of -k i n the method involving t r i a l values of -k can be made from the equations -k x 100 Hp = 2.273 - 2.262 k* and -k x 100 L p,= 1.635 - 1.475 k*. The resultant values can then:be used to bracket the probable value since the experimental high and low plane of n u t r i t i o n are probable extremes i n comparison to wild populations. THE EFFECT OF SEX AND THE PLANE OF NUTRITION UPON THE AGE AT WHICH MATURE SIZE IS ATTAINED Small differences i n rates of growth or i n the rate of decline i n growth rate, or both, markedly a f f e c t 138 0 9 r 0-6 0 7 0-8 0-9 10 Rate of growth (k*) Fig. 25. A regression of the rate of decline in growth on the rate of growth for low plane males. 139 the age at which mature size i s attained. Consequently the small differences i n these rates shown e a r l i e r , are magni-f i e d by the comparisons of differences i n age-of maturity. Simi l a r l y , however, the variances are magnified so that the r e l i a b i l i t y of differences between group means i s reduced. Thus, the small samples used i n th i s experiment were not expected to y i e l d s t a t i s t i c a l l y / s i g n i f i c a n t differences i n th i s parameter. Table XXII shows the mean ages at which the mature siz e (A) of each l i n e a r measurement was attained for high plane males, females and low plane males of the Van-couver Island race. As could be expected from the e a r l i e r findings with regard to weight growth, the females tend to mature much more rapidly than do the males. The d i f f e r -ences between the means are not s t a t i s t i c a l l y d i f f e r e n t and therefore larger sample sizes are required for absolute proof. In spite of the lack of s i g n i f i c a n t differences, i t i s l i k e l y that s k e l e t a l growth reaches maturity much more quickly i n the females because of-the growth retarding influence of female sex hormones as was suggested to explain the differences i n the behaviour of weight growth. A comparison of the age of attainment of mature size between measurements for the high plane females shows that the chest g i r t h matures much l a t e r than do the other measurements. This finding i s i n keeping with the 140 rel a t i o n s h i p between chest g i r t h and the slowly maturing body mass. The s i g n i f i c a n t differences between height-at-withers and head width and between head width and head length tend to indicate that the growth of the head width i n the female, r e l a t i v e to i t s mature size i s extremely rapid. This i s mostly due, as was shown e a r l i e r , to a very rapid rate of decline i n growth rate for the female head width measurement and not to large differences i n growth rates between sexes. The lack of similar s i g n i f i -cant differences between measurements for the high plane males i s probably due to a higher degree of v a r i a b i l i t y i n the growth rate of the males. Table XXII. The mean ages at which the mature size (A) of each li n e a r measurement was attained for high plane males, high plane females and low plane males of the Vancouver Island race.(Age i n days) Sex and Plane Height @ Chest Hind Leg Head Head Hip of N u t r i t i o n Withers Gir t h Length Length Width Width HPcf 668 \ 5 1020 1 533 487 -HP 9 4853 8432 373 4914. LPti* 1050 975 - 975 662 ; 468 1913,4^ 309 472 279 1113 1. D i f f e r s s i g n i f i c a n t l y at the 95% l e v e l from a l l other HP<5* values. 2. D i f f e r s s i g n i f i c a n t l y at the 95% l e v e l from a l l other HP$ values. 3. D i f f e r s s i g n i f i c a n t l y at the 95% l e v e l from other values marked 3. 4. D i f f e r s s i g n i f i c a n t l y at the 95% l e v e l from other values marked 4. 5. In v e r t i c a l comparisons, means joined by a l i n e 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,one another at the 95% l e v e l , Duncan's New Multiple Range Test. 141 The low plane of n u t r i t i o n resulted i n a retarda-tion of the rate at which the mature size was achieved i n a l l measurements except chest g i r t h and head width. The l a t t e r may indicate that a smaller mature siz e i s achieved r e l a t i v e l y more rapidly as a r e s u l t of the low plane of n u t r i t i o n . This i s thought to be true for chest g i r t h because a- s i g n i f i c a n t l y small value for A was found (See Table XXI). The same reasons may apply to the head width measurement but confirmation i s lacking because of the i n s i g n i f i c a n t differences found for high and low plane males. Even though the low plane of n u t r i t i o n appears to cause a general increase i n the age at which mature size i s reached i n a l l but the above mentioned measurements, the data show s i g n i f i c a n t . d i f f e r e n c e s only for the hind leg length and hip width of the high and low plane males. These r e s u l t s are probably associated with a smaller v a r i -ation and less measurement error i n hind leg length and hip width data but they are also associated with a greater degree of growth retardation. Thus the low plane of n u t r i -tion appears to a f f e c t the age at which mature size i s reached i n these dimensions, to a greater degree than the others. If a:larger sample siz e should reveal s i g n i f i c a n t differences i n the value of A, then the growth curves of high and low plane deer would not converge at maturity. Thus, absolute, age-specific measurements of these two 142 dimensions could be used to quantify the environmental potential for growth, as shown by Klein (1957, 1959, 1963, 1964) for Sitka deer. If no difference can be demonstrated in the value of A, as was found i n t h i s experiment, then i the growth curves of the two planes of n u t r i t i o n would converge. Thus, absolute age-specific size of the hind leg and hip width would be useful i n comparisons between popu-l a t i o n only u n t i l approximately 80 - 90% of the mature size has been reached. This would occur at approximately 2 1/2 years on a low plane and one year under good growing con-d i t i o n s . It i s expected, however, that i n any population such values would reveal large variations within age classes and hence, hind leg length or hip width by them-selves would not be useful as an index to population wel-fare. As a r e s u l t of the s i m i l a r i t i e s i n growth rates and rates of decline i n growth, shown e a r l i e r , i t i s con-cluded that no large changes i n body form occur i n deer as a r e s u l t of increasing s i z e . It i s apparent however, from Table XXII, that some measurements mature more rapidly than others, (e.g. hind leg and height-at-withers and head length and head width) and that larger sample sizes would probably reveal other si m i l a r differences i n the age at which mature siz e i s attained for other measurements. Consequently, r a t i o s of the absolute values of any two measurements show progressive changes up to the point when 143 there i s no further increase i n the more slowly maturing measurement. For example, the r a t i o of head length to head width, for high plane Vancouver Island males, changes from a mean value of 1-203 at b i r t h to 1*305 when both measurements have reached their mature sizes. S i m i l a r l y , the mean value for the females changes from 1*302 at b i r t h to 1*464 at maturity. Such changes i n the r a t i o s of linear measurements indicate that minor differences i n form accompany development i n deer but they cease to change at an early age. THE EFFECT OF SEX AND THE PLANE OF NUTRITION UPON THE RELA-TIVE PROPORTIONS OF CERTAIN LINEAR MEASUREMENTS Ratios of mature sizes for certain measurements were examined to determine whether differences i n form might accompany differences i n sex and the plane of n u t r i -tion. It i s possible that the smaller stature of the female and the small size of the low plane deer may demon-strate s i m i l a r p r o p o r t i o n a l i t i e s i f the growth i n h i b i t i n g factor affects a l l parts of the body s i m i l a r l y . On the other hand,the growth i n h i b i t i n g factors may a f f e c t various parts d i f f e r e n t l y as has been shown by McMeekan (1940, a, b, c ) , Palsson and Verges (1952), and Moulton, et a l . (1921). E a r l i e r , i t was demonstrated that s i g n i f i c a n t differences i n mature sizes (A) were found for height-at-144 withers, hind leg length and head width (see Table XIX) . These measurements were therefore u t i l i z e d i n forming the r a t i o s shown i n Table XXIII. Examination of these r a t i o s suggests that the growth retarding influence of the female sex hormones r e s u l t s i n very s l i g h t , i n s i g n i f i c a n t d i f f e r -ences i n the derived values, whereas the plane of n u t r i t i o n appears to have a more profound a f f e c t upon r e l a t i v e pro-portions. It should be noted that high F - values obtained i n the analysis of variance indicate that for the f i r s t two r a t i o s , differences between the planes of n u t r i t i o n are probably r e a l . S i m i l a r l y , the close agreement between mean differences for the two planes of n u t r i t i o n and. the computed least s i g n i f i c a n t range i n the t h i r d r a t i o suggests that differences between planes of nutrition;may be r e a l but more data of a si m i l a r nature i s required to produce defin-i t e s t a t i s t i c a l proof. If one assumes that the differences shown are r e a l , then one might conclude that the propor-t i o n a l i t y of parts i n the adult i s si m i l a r for the f i r s t , second and fourth r a t i o s whereas the head length/head width r a t i o d i f f e r s between sexes. Consequently, the growth i n h i b i t i n g influences i n the female appear to cause a similar reduction i n the growth of body parts with the exception of head length. If the differences between planes of n u t r i t i o n are r e a l , then the low plane appears to a f f e c t the propor-t i o n a l i t y of parts through a d i f f e r e n t i a l e f f e c t upon the 145 growth of the various measurements. Provided that the plane of n u t r i t i o n remains constant, the proportionality of such parts may provide a means of id e n t i f y i n g i n d i v i d u a l s on d i f f e r e n t planes of n u t r i t i o n after mature size has been attained. Table XXIII. The e f f e c t of sex and the plane of n u t r i t i o n upon the r a t i o s of cer t a i n linear measurements for the Vancouver Island race of deer using mature sizes (A). Ht.@ W/HL H L/Hip W. Hd.L/Hd.W. Chest Girth/H L HP<5» 2.030" 1 2.3461 1 .305i 2.0701 HP? 2.015 2.290J 1.464i 2.024-= LP<5* 1.896J 2.573J 1 .419i 1 .579 Means joined by a l i n e 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 one another at the 95% l e v e l of confidence, Duncan's New Multiple Range Test. Of the four r a t i o s examined the chest girth/hind leg r a t i o appears to respond most s i g n i f i c a n t l y to the plane of n u t r i t i o n . Consequently, t h i s r a t i o may provide a suitable index to the condition of individ u a l s and popu-la t i o n s . Bandy, et a l . (1956) proposed a method for the assessment of condition i n wild ungulates using estimated weights based on chest g i r t h and hind foot measurements. The method has not proven useful on harvested deer (Klein, 1957) because of the errors involved i n making estimates of body weight from linear measurements and because the hind foot matures at an early age so that further predictions of weight from t h i s dimension are impossible. The present 146 data suggest that a more suitable index of condition, not involving estimates of weight, could be developed by form-ing a r a t i o between an element which i s r e l a t i v e l y unaf-fected by the plane of n u t r i t i o n , as for example, hind leg length and an element which tends to fluctuate with con-d i t i o n . The actual weight i t s e l f i s undoubtedly the best measurement of a f l u c t u a t i o n i n condition but i n f i e l d studies a dressed weight to hind foot length r a t i o might prove useful. However, chest g i r t h has been shown to fluctuate seasonally and i t has been shown to be s i g n i f i -cantly affected by the plane of n u t r i t i o n through the magnitude of mature size achieved (see Table XXI). Fur-thermore, the r a t i o of chest g i r t h and hind leg length does not appear to d i f f e r between sexes as does weight (Table XXIII). The l a t t e r i s of p a r t i c u l a r importance where i n small samples, both males and females may be grouped together to obtain an index of condition. Because of a d i f f e r e n t i a l growth rate between chest g i r t h and the hind foot length, and because both reach their respective mature sizes at d i f f e r e n t ages, the r a t i o of chest g i r t h to hind leg length changes during the period of growth. Table XXIV shows these changes from b i r t h to maturity i n stated i n t e r v a l s of time. Because of these age-specific changes i n the r a t i o on given planes of n u t r i t i o n , attempts to quantify, condition with t h i s r a t i o must account for age-class differences. I t i s important 147 to note that the two widely separated planes of n u t r i t i o n used i n thi s experiment resulted i n an almost s t a t i s t i c a l l y s i g n i f i c a n t difference i n mean values at a very early age (250 days). Highly s i g n i f i c a n t differences were demon-strable from 500 days to maturity and i t i s considered that t h i s method of quantifying condition may prove useful i n f i e l d studies. Table XXIV. Progressive changes i n the chest g i r t h to hind leg length r a t i o for males of the Vancouver Island race related to increasing age on two planes of n u t r i t i o n . Plane of Nut r i t i o n 0 250 Age i n 500 Days 750 1000 At Maturity HPc? 1. 291 1.845 1.936 1.993 2.048 2.070 NS P>0.1 P>.01 P>.01 P>.01 P>.01 LPtf* 1.244 1.555 1.597 1.584 1.592 1.579 COMPARATIVE LINEAR GROWTH CHARACTERISTICS OF FOUR RACES OF BLACK-TAILED DEER Four races of deer were used i n t h i s experiment in order to determine i f each race d i f f e r e d from the others in some c h a r a c t e r i s t i c s of the i r growth patterns. The res u l t i n g comparisons are r e s t r i c t e d to the high plane males of a l l four races because larger samples were a v a i l -able for analysis and because the high plane of n u t r i t i o n was thought to reveal genetic differences and s i m i l a r i t i e s . Low plane males might show differences in growth patterns 148 re s u l t i n g from gen e t i c a l l y d i f f e r e n t e f f i c i e n c i e s of food u t i l i z a t i o n or differences i n the p r i o r i t i e s for n u t r i -ents on the low plane diet but i n s u f f i c i e n t numbers of animals were available for analysis. Comparative growth patterns of various races under controlled n u t r i t i o n a l conditions are important to taxonomic considerations. Usually, i t i s impossible to compare measurements from specimens of given ages which have sim i l a r n u t r i t i o n a l h i s t o r i e s . Consequently, r a c i a l differences may appear which r e s u l t from age-specific or environmental bias i n the samples being compared. On the other hand, the growth patterns and consequent measurements may bear no resemblance to the wild parent populations when indi v i d u a l s are raised on optimal n u t r i t i o n a l conditions i n a controlled experiment. However, i f differences i n the genetic p o t e n t i a l for growth exi s t , they can only be sep-arated from environmental influences under controlled or standard conditions. Table XXV shows the parameters of growth for the four races of high plane male deer when raised i n the same environment. It i s evident that the s i m i l a r i t i e s i n growth patterns of a l l four races outnumber s i g n i f i c a n t d i f f e r -ences. In the estimated size at b i r t h , the Mule deer i s s i g n i f i c a n t l y larger than the other three races i n height-at-withers, hind leg length and possibly head length. The Table XXV. Comparative growth c h a r a c t e r i s t i c s of high plane males of four races of black-t a i l e d deer. HP A (cms) -k x 100 k* Race Cal. Sitka V.I. M.D. Cal. Sitka V.I. M.D. Cal. Sitka V.I. M.D. n = 2 3 5 4 2 3 5 4 2 3 5 4 Height-at-withers 86.517 93.697 89.796 105.629 .711 .579 .599 .651 .550 .752 .737 .717 Chest g i r t h 89.119 94.537 91.570 100.929 .490 .426 .422 .544 .782 .807 .808 .785 Hind leg length 43.129 44.765 44.242 53.295 .682 .617 .592 .634 .718 .743 .767 .737 Head length 27.826 30.884 28.203 33.561 .625 .456 .553 .515 .721 .805 .759 .771 Head width 25.517 22.879 21.687 22.958 .277 .520 .582 .679 .880 .806 .744 .720 Hip width 20.992 19.273 18.910 22.911 .559 .638 .577 .569 .789 .725 .743 .747 Note: Means ; joined by lines are not s i g n i f i c a n t l y d i f f e r e n t at P = . 05 according to Duncan's New Multiple Range Test. CD Table XXV (cont'd.) HP Size @ B i r t h (cms) Age @ Maturity (days) Race Cal. Sitka V.I. M.D. Cal. Sitka V.I. M.D. n = 2 3 5 4 2 3 5 4 Height-at-rwithers 32.2 35.9 36.1 41.3 604 712 668 648 Chest g i r t h 30.5 28.8 28.1 29.7 1010 1050 1020 790 Hind leg length 20.9 22.0 21.7 25.9 474 508 533 527 Head length 13.7 14.8 14.2 15.3 1 483 637 487 568 Head width 12.2 12.4 11.8 12.2 931 514 468 396 1 Hip width 8.2 7.4 7.3 8.2 566 393 472 489 Note: Means joined by lines are not s i g n i f i c a n t l y d i f f e r e n t at P = .05 according to Duncan's New Multiple Range Test. 1 Means which may be s i g n i f i c a n t l y d i f f e r e n t i f the sample size i s increased by a small number. 151 establishment of the l a t t e r requires a larger sample size but the differences i n means cl o s e l y approximates the least s i g n i f i c a n t ranges i n Duncan's New Multiple Range Test, thereby suggesting a probable difference between Mule deer and the other three races. These differences are maintained throughout l i f e with the r e s u l t that the estimated mature sizes (A) of height-at-withers, hin,d leg length and head length d i f f e r s i g n i f i c a n t l y from the other races. As no s i g n i f i c a n t differences i n growth rate (k*) or i n the rate of decline i n growth rate (-k) were demonstrable, i t means that at any given s i z e , the growth of these elements i s faster i n the Mule deer than i s expected on the basis of the other three races. An alternate explanation involving growth over a longer period of time i s refuted by the absence of s i g n i f i c a n t differences i n the mean age at maturity. Thus, the l i n e a r growth pattern of the Mule deer appears to d i f f e r s i g n i f i c a n t from those of the other three races. In terms of the mature si z e of the head length, the Mule deer d i f f e r s from the Vancouver Island and C a l i -fornian races of Columbian B l a c k - t a i l s but does not d i f f e r s i g n i f i c a n t l y from the Sitka B l a c k - t a i l e d deer. The s i m i l a r i t y of these two races i s probably due to the r e l a -t i v e l y but i n s i g n i f i c a n t l y greater size at b i r t h shown for the Sitka deer. The Sitka deer tends to demonstrate a r e l a t i v e l y low growth rate (k* = .805) and a proportionately 152 low rate of decline i n growth (-k x 100 = .456). In th i s way i t i s able to maintain i t s r e l a t i v e position among the races with the resultant large mature size of the head. In the width of the hip, the Mule deer d i f f e r s i n mature si z e from the Sitka deer and the Vancouver Island races but does not d i f f e r from the C a l i f o r n i a n B l a c k - t a i l . These differences are not explicable from the character-i s t i c s presented because of the s i m i l a r i t i e s of a l l four races i n s i z e - a t - b i r t h , rate of decline i n growth rate, i n the rate of growth and i n the age-at-maturity. The only other differences i n growth character-i s t i c s found for the four races indicates that the Cal-i f o r n i a n B l a c k - t a i l d i f f e r s from the other three races i n the rate of growth (k*) of the height-at-withers measure-ment. The C a l i f o r n i a n race of b l a c k - t a i l s appears to grow in height, r e l a t i v e to i t s mature size much more rapidly than the other three races. As a r e s u l t , the rate of decline i n growth rate (-k x 100) i s more rapid for the Ca l i f o r n i a n deer but due to the small sample size the difference i n th i s c h a r a c t e r i s t i c i s not shown to be s i g -n i f i c a n t . The values of A for a l l four races and for a l l measurements except head width and hip width indicate that there are r a c i a l differences i n the mature size attained. 153 Thus the C a l i f o r n i a n B l a c k - t a i l appears to reach the smal-l e s t mature siz e followed by the Vancouver Island Black-t a i l , the Sitka deer and the Mule deer. The two measure-ments of width (head and hip) indicate that the C a l i f o r n i a n race may be r e l a t i v e l y wider than any other race, except for the much larger Mule deer. Consequently measurements of width, p a r t i c u l a r l y of the s k u l l , when related to measurements of length or height may indicate that the C a l i f o r n i a n B l a c k - t a i l d i f f e r s s i g n i f i c a n t l y from the Van-couver Island race. Table XXVI, showing some r e l a t i v e portions of c e r t a i n l i n e a r measurements at maturity indicates that the C a l i f o r n i a n race d i f f e r s s i g n i f i c a n t l y from the other three in terms of the head length/head width r a t i o and also an apparent, though not s i g n i f i c a n t , difference i n the hind leg length/hip width r a t i o . It i s therefore l i k e l y that standard taxonomic c h a r a c t e r i s t i c s can be used to separate the C a l i f o r n i a n and Vancouver Island races of the Columbian B l a c k - t a i l e d deer on the basis of length to width propor-t i o n s . The remaining r a t i o s shown i n Table XXVI indicate no other s i g n i f i c a n t differences i n body form with the excep-tion of a s i g n i f i c a n t difference between the Mule deer and the Columbian B l a c k - t a i l s from Vancouver Island i n terms of the head length to head width r a t i o . This suggests that 154 the Sitka B l a c k - t a i l s and the Mule deer may be more cl o s e l y related than either of these races i s to the Columbian B l a c k - t a i l race.. This i s also born out by the s i m i l a r i t i e s and differences i n the mature sizes of the various measurements shown i n Table XXV. Table XXVI. Relative proportions of some lin e a r measure-ments at mature sizes (A) i n the high plane males of four races of deer. Race Ht.@ W/HL H L/Hip W. Hd.L/Hd.W. Chest/H L C a l i f o r n i a 2.006 i 1 2.006i * 1.094 2.062i Alaska 2.010 2.322 1.352ii 2.108 Vancouver Island 2.030 2.347 1.305U 2.070 Mule 1.983J 2.33lJ 1.464J 1.895J * Relatively high F-value indicates that the C a l i f o r n i a n race may d i f f e r from the others. 1 Means joined by a l i n e 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 one another at the .05% l e v e l according to Duncan's New Multiple Range Test. The chest g i r t h to hind leg length r a t i o for high plane male deer shows no s i g n i f i c a n t differences between races. It i s l i k e l y , however, that the Mule deer w i l l be found to d i f f e r s i g n i f i c a n t l y i n samples of larger s i z e because of the proportionately large hind leg length i n th i s race. Therefore, with the exception of the Mule deer, i t may be possible to compare the condition of deer on the basis of chest girth/hind leg r a t i o s from widely divergent habitats and from widely separated geographical locations, i r r e s p e c t i v e of race. 155 In summary, i t i s apparent that the characteris-t i c s of lin e a r growth patterns analysed i n t h i s experiment indicate that the Mule deer d i f f e r s markedly from the other three races when raised under i d e n t i c a l environmental con-di t i o n s . The Sitka deer also shows some unique character-i s t i c s of growth but more cl o s e l y resembles the Mule deer than the Columbian B l a c k - t a i l e d deer. Slight differences i n the growth patterns of C a l i f o r n i a n and Vancouver Island stocks of the Columbian B l a c k - t a i l race suggests that fur-ther studies with larger numbers raised on a high plane of n u t r i t i o n may reveal s i g n i f i c a n t r a c i a l differences i n growth patterns and r e l a t i v e growth r a t i o s . 156 CONCLUSIONS The patterns of growth i n body weight of males and females from a l l four races of deer exhibited seasonal fluctuations i n spite of a constant n u t r i t i o n a l environment. Periods of rapid summer growth were followed by s t a t i c or declining patterns of weight change which was associated with a voluntary reduction,in food intake. In the males, growth was reduced at the time antler velvet was stripped and body weight declined i n association with r u t t i n g behaviour and reduced food intake. Following.rut, food intake Was maintained at a s l i g h t l y increased l e v e l for the remainder of the depressed winter growth. The females d i s -played the same seasonal pattern of growth but the f l u c t u -ations i n body weight were reduced i n magnitude. The depressed l e v e l of food intake was not as marked as i n the females and was believed to be similar to the post-rutting l e v e l found for the males. The females showed no d i f f e r e n t or increased a c t i v i t y patterns which could be associated with reproduction so that the reduction i n dai l y food con-sumption i s considered to be related to a seasonal depres-sion i n growth impulse. The seasonal patterns of growth suppression d i f -fered with increasing age. In the f i r s t period of suppres-sion, growth of the fawns was markedly reduced but the reduced rate was maintained throughout the winter r e s u l t i n g 157 i n a s l i g h t increase i n body weight. In the second winter, some ind i v i d u a l s l o s t small amounts of weight while others were able to maintain their body weight. In each ensuing period of winter growth suppression a l l deer l o s t weight. I t i s concluded therefore, that periods of growth suppression , d i f f e r q u a l i t a t i v e l y with increasing age, probably as a r e s u l t of a decreased growth impulse, a greater degree of interference related to physiological changes associated with reproduction and a difference i n the degree of tissue storage and u t i l i z a t i o n . The seasonal growth response of i n d i v i d u a l deer on high plane showed that the actual course of summer growth was si m i l a r i n magnitude i n a l l years. Thus the absolute growth response was not d i r e c t l y related to body siz e or to the difference between actual and mature siz e but dependent upon the nature and degree of the proceeding winter weight change. As a r e s u l t , the absolute gains were sim i l a r to, and i n some cases, larger than the growth response for the same i n d i v i d u a l at younger ages. In a r e l a t i v e sense how-ever, each succeeding period of rapid growth was proportional to body mass and to the difference between body weight and mature si z e . Consequently, seasonal growth resulted i n a curve of maximum weights which was sigmoid i n nature. Linear growth, as demonstrated by six body measurements, did not follow a seasonal pattern of rapid and 158 retarded growth, except i n the chest g i r t h measurement. The l a t t e r showed a depressed winter growth rate s i m i l a r to that of weight as a r e s u l t of i t s association with body volume and hence, with body weight. The remaining measurements grew continuously from b i r t h towards a mature si z e . Groups fed a low plane of n u t r i t i o n tended to demonstrate a si m i l a r but reduced seasonal pattern of weight growth and a continuous pattern of li n e a r growth as found i n the high plane groups. Because the low plane di e t was found to be quantitatively inadequate during the winter, low plane groups were fed at a s l i g h t l y higher l e v e l than during the summer. As a r e s u l t , i t was found that deer on quantita-t i v e l y inadequate diets were capable of maintaining a low l e v e l of growth during the winter. Hence, i t i s concluded that seasonal environmental factors do not influence the growth patterns of deer on inadequate diets to the same degree shown by well fed animals. This may be due to the retention of a strong growth impulse and to a reduction i n the degree of interference r e s u l t i n g from changes i n physi-o l o g i c a l condition associated with reproduction. The high plane deer of a l l four races studied reached maximum seasonal weights at d i f f e r e n t calendar dates which were c h a r a c t e r i s t i c for each race. Since peak weights were also associated with the reproductive period, the differences r e f l e c t innate patterns of timing i n the onset 159 of reproduction. Moulting, shedding of velvet and antler drop followed a sim i l a r pattern with the Ca l i f o r n i a n Black-t a i l s being the e a r l i e s t , followed by the Mule deer, Sitka deer and the Vancouver Island race of the Columbian Black-t a i l s . Marked differences i n timing were found for each race i n their f i r s t year of l i f e but there appeared to be a progressive adjustment, so that the dates at which maximum weights were reached i n the t h i r d year were sim i l a r for a l l four races. It was concluded that an innate timing mechanism i s found i n deer from d i f f e r e n t geographical locations and that a progressive adjustment to environmental trigger mechanisms i s possible when deer are relocated i n one place. The environmental factors responsible for the observed timing could not be determined from t h i s study but the observed order of cl i m a t o l o g i c a l c h a r a c t e r i s t i c s tend to rule out some possible evocators of rut and favour others. The seasonal pattern of weight growth made i t d i f f i c u l t to quantitatively compare growth patterns related to the plane of n u t r i t i o n , sex and race. It was evident, however, that the maximum weights reached each year and the growth of the f i r s t summer described a sigmoid curve which i n f l e c t e d at approximately 25% of the mature weight. This curve was c a l l e d the e f f e c t i v e curve of growth as compared to a basic curve, developed from.the minimal seasonal weights, or the actual course of seasonal growth. The ef f e c t i v e curve of growth was f i t t e d i n two parts to the 160 equations W = A e k t and W = A - B e - k t for the s e l f -accelerating and s e l f - i n h i b i t i n g phases of growth respec-t i v e l y . These equations resulted i n excellent f i t s and permitted comparison of growth patterns on the basis of the parameters k, (instantaneous r e l a t i v e growth rate), -k (instantaneous r e l a t i v e rate of decline i n growth rate) and A, (the asymptotic, mature :size). The basic curve of growth was found to f i t the equation representing the s e l f -i n h i b i t i n g phase while seasonal growth was f i t t e d adequately with the s e l f - a c c e l e r a t i n g equation. Patterns of li n e a r growth resulted in;exponential curves which f i t t e d the equation L = A - B e - k t with excel-lent precision, thereby permitted comparisons to be drawn i n a s i m i l a r fashion to those for the s e l f - i n h i b i t i n g phase of weight growth. In addition, a d i r e c t expression of the rate of growth, k* = L- +^2 ~ Lt+1 was used for comparisons Lt+1 - Lt+0 of races, sexes, plane of n u t r i t i o n and d i f f e r e n t measure-ments. The point of i n f l e c t i o n of the e f f e c t i v e curve of weight growth did not appear to be correlated with either weaning or overt evidence of puberty. The i n f l e c t i o n point, determined by the in t e r s e c t i o n of s e l f - a c c e l e r a t i n g and s e l f - i n h i b i t i n g phases, occurred after weaning was com-pleted and before there was any outward evidence of puberty. Body size at the i n f l e c t i o n , but not age, was found to be : i 6 i c h a r a c t e r i s t i c for each race. Examination of instantaneous r e l a t i v e growth rates for body weight computed for high plane males i n the e f f e c t i v e curve of growth of a l l races indicated that deer which grew slowly i n the s e l f - a c c e l e r a t i n g phase tend to have a slow rate of decline i n growth i n the s e l f - i n h i b i t i n g phase. The reverse was also found to be true and further-more, the values of k and -k showed no c o r r e l a t i o n with size at maturity. Thus the value of the mature size (A) i s determined by the general n u t r i t i o n a l plane and genetic factors, while the rates of growth leading to mature size varies to a greater degree than mature size i t s e l f . Con-sequently, some deer which are ultimately small i n size may grow as rapidly as larger deer. It was also found that the age of weaning, length of the weaning period, i n f l e c t i o n age and i n f l e c t i o n weight, within the range of v a r i a t i o n found i n t h i s experiment, did not a f f e c t the magnitude of the mature size. As a r e s u l t the computed age at maturity ranged from 5.87 to 15.76 years with an average of 10.26. In th i s regard the females matured more rapidly attaining their smaller mature sizes at a range of 3.48 years to 10.50 years and an average of 4.79 years. The e f f e c t i v e curve of growth for high plane females d i f f e r e d from that of males i n several ways. Growth rates i n the s e l f - a c c e l e r a t i n g phase of weight 162 growth were greater and the rates of decline i n growth rates i n the s e l f - i n h i b i t i n g phases were more rapid than was found for males, thereby r e s u l t i n g i n early maturity. In addition, the s e l f - a c c e l e r a t i n g phase of growth for high plane females was found to be shorter than for males and consequently, the females weighed less at the point of i n f l e c t i o n . These differences are thought to be related to the e f f e c t of female sex hormones upon the impulse to grow. The f i t t i n g of curves of li n e a r growth for various measurements permitted comparisons to be made between measurements with regard to mature size, rate of decline i n growth rate and the percentage of mature size achieved at b i r t h . With respect to the l a t t e r , i t was found that head length, head width and hind leg length were developed to the greatest degree at b i r t h with the head length being s i g n i f i c a n t l y smaller than head width. Height-at-withers, chest g i r t h and hip width were the least developed at b i r t h with the chest g i r t h being s i g n i f i c a n t l y developed to the smallest degree as a r e s u l t of i t s re l a t i o n s h i p to body volume and mass. Comparisons of d i f f e r e n t measurements of the high plane males with regard to growth rate (k*) and the rate of decline i n growth (-k) showed that there were no s i g n i f i c a n t differences between measurements although there was a tendency for those elements which had attained the 163 smallest proportion of th e i r f i n i t e size to grow most rapidly. In general, however, the lack of s i g n i f i c a n t d i f -ferences i n growth rates of various measurements indicates that ther© i s an o v e r a l l c o n t r o l l i n g pattern which prevents marked changes i n r e l a t i v e body proportions from occurring with increasing s i z e . Comparisons of li n e a r growth values, k* and -k, f o r various high plane i n d i v i d u a l s showed that, i n a sim i l a r fashion to weight growth, they are not correlated with the mature siz e (A). Consequently the magnitude of the mature size appears to be i n t r i n s i c a l l y fixed on a given plane of n u t r i t i o n while the pathway with respect to rate of growth and rate of decline i n growth may vary i n r e l a t i o n to environmental opportunity. Thus, as growth rates increase there i s an increase i n the rate of decline i n growth as was shown for weight growth. Consequently, for a given plane of n u t r i t i o n , the value of -k can be estimated from the equation ~k x 100 = 2.273 - 2.262k* i f the value for k* i s determined from early growth data. Linear growth patterns of females was found to be si m i l a r to those of males with the exceptions that the magnitude of the mature size was reduced and they reached mature size at e a r l i e r ages. No s i g n i f i c a n t differences between sexes were found i n estimated b i r t h size but females showed more rapid rates of growth (k*) and more 164 rapid rates of decline than did males. A regression of -k on k* for a l l measurements resulted i n the equation - k x 100 =2.689 - 2.759 k* thereby i n d i c a t i n g that for a given rate of growth, there i s a more rapid rate of decline i n female growth patterns. In respect to the magnitude of mature sizes for both sexes, the height-at-withers, head width, and hind leg length were found to be s i g n i f i c a n t l y smaller for the females. No s i g n i f i c a n t differences between sexes.were found i n chest g i r t h or hip width but the lack of s t a t i s t i -c a l separation.in these parameters i s believed due to r e l a t i v e l y high degrees of v a r i a b i l i t y and small samples. In contrast, the remarkable s i m i l a r i t i e s i n the mature siz e of the head length measurements indicate that i n t h i s res-pect the sexes do not d i f f e r . Thus, the elements composing head length appear to escape the l i m i t a t i o n s placed on growth by the female physiology thereby giving r i s e to the disproportionately long nosed appearance of older does. Ratios of r e l a t i v e proportions derived from the mature sizes of c e r t a i n measurements from high plane deer showed no s i g n i f i c a n t differences between sexes, except i n the head length to head width r a t i o , thereby indicating the dispro-portionately longer head length r e l a t i v e to width i n the females. The low plane of n u t r i t i o n affected the shape of 165 weight growth curves, tending to obscure the sigmoid form of e f f e c t i v e growth. The low plane curves were shaped so that they could be f i t t e d i n their entirety to the equation W = A - Be~ k t because they did not demonstrate an obvious s e l f -accelerating phase. It was possible to f i t both s e l f -accelerating and s e l f - i n h i b i t i n g forms of the growth equa-tion only by v i s u a l l y comparing high and low plane curves in order to obtain values of k and -k for comparative pur-poses. It i s concluded therefore that an inadequate diet can influence the form of the growth curves of body weight. One i n d i v i d u a l was removed from a low plane of n u t r i t i o n at 860 days of age and placed upon the high plane feeding schedule. The response i n weight growth was immedi-ate and within one year i t had reached the l e v e l of i t s high plane counterparts. This demonstrates that deer on inadequate diets r e t a i n the a b i l i t y to grow after a lengthy period of suppression i f environmental factors permit. It i s not known however, i f the growth compensation which occurred resulted i n differences i n body composition, nor to what age the a b i l i t y to compensate i s retained. As was to be expected, weight growth of a l l low plane deer was markedly reduced by the plane of n u t r i t i o n . In the comparisons used, the mature siz e (A) was reduced by an average of 54% and the rate of growth (k) i n the s e l f - a c c e l e r a t i n g phase of the e f f e c t i v e curve of growth 166 was reduced to 42.8% of that shown by the high plane deer. Furthermore, the low plane of n u t r i t i o n caused an increase in the rate of decline (-k) i n the second phase growth rates which would have been even greater i f i t had not been necessary to increase the feeding l e v e l during the winter. It i s evident that growth rates of mass and the mature body weight are d i r e c t l y related to environmental opportunity except where such opportunity permits the expression of g e n e t i c a l l y controlled maximums. This con-clusion i s i n d i r e c t contrast with the finding that the low plane of n u t r i t i o n did not a l t e r the mature size of any of the l i n e a r measurements except chest g i r t h . Thus, the mature siz e i n terms of li n e a r dimensions appeared to be gene t i c a l l y controlled and was r e l a t i v e l y independent of the plane of n u t r i t i o n . The rate of growth (k*) for the li n e a r dimensions was decreased for a l l measurements by the low plane of n u t r i t i o n but s i g n i f i c a n t differences occurred only i n the height-at-withers, head length and hip width measurements. On the other hand, the rate of decline i n growth rate (-k) was decreased by the low plane diet thereby permitting the deer to att a i n their genetic maximum sizes at somewhat older ages. Thus the rate of growth and rate of decline i n growth i s responsive to environmental factors, such as 167 di e t , whereas the mature siz e of linear elements i s geneti-c a l l y controlled and does not r e f l e c t n u t r i t i o n a l inadequ-c i e s . A regression of -k and k* for a l l l i n e a r measure-ments from the low plane r e s u l t s , indicates that for a given value of k* there i s a correspondingly smaller value of -k as compared to corresponding high plane parameters. It i s therefore suggested that i n order to predict -k from early growth values, regressions of -k and k* for both high and low plane should be used. Since the planes of n u t r i -tion used i n this experiment are probably higher and lower than would occur i n most natural populations the resultant estimates of the rate of decline i n growth w i l l tend to bracket the actual value. The r e l a t i v e proportions of cert a i n l i n e a r elements, i n terms of the mature values, were influenced to a greater degree by the plane of nu t r i t i o n : than by sex. The r a t i o of hind leg length/hip width was increased by the low plane of n u t r i t i o n while the r a t i o of height-at-withers/ hind leg length; head length/head width and chest girth/hind leg length were reduced. Only the l a t t e r proved to be s i g -n i f i c a n t l y d i f f e r e n t between the two planes of n u t r i t i o n . For t h i s reason, and because chest g i r t h tends to follow weight growth' patterns, the chest girth/hind leg length i s suggested as a possible method for quantifying the condition 168 of deer. The r a t i o appears to r e f l e c t differences i n the plane of n u t r i t i o n as early as 250 days of age and at 500 days, differences were found to be s t a t i s t i c a l l y , s i g n i f i -cant. Since no differences i n t h i s r a t i o occurred between sexes, i t i s possible to lump the values derived from both sexes: i n quantitatively evaluating condition,in wild popu-la t i o n s . Racial comparisons of growth parameters demon-strate that the Mule deer d i f f e r s markedly from the other three stocks. The Mule deer i s the fast e s t growing of a l l four races, reaches .the largest mature size and attains mature size at a much e a r l i e r age. In some parameters, however, th i s race i s sim i l a r to others. For example, the mature size of the l i v e head length measurement did not d i f f e r from that of the Sitka deer and i n hip width i t d i f -fers from only the C a l i f o r n i a n stock of the Columbian Black-t a i l e d deer. The male,Alaskan, Sitka deer i s p o t e n t i a l l y the second largest of the four races, grows rapidly i n the f i r s t phase of weight growth and demonstrates a r e l a t i v e l y slow rate of decline i n the s e l f - i n h i b i t i n g phase. I t i s simi l a r to the Mule deer i n the mature siz e of the head length measurement and d i f f e r s from both stocks of Columbian B l a c k - t a i l s i n the head length.to head width r a t i o . The C a l i f o r n i a n and Vancouver^Island stocks are 169 the smallest i n mature weight with the Ca l i f o r n i a n deer tending to be larger than those from Vancouver Island. The Ca l i f o r n i a n stock shows the slowest rate of growth i n the f i r s t phase of weight increase and a r e l a t i v e l y slow rate of decline i n growth rate i n the s e l f - i n h i b i t i n g phase. It i s also the smallest of the four stocks with respect to most linear dimensions but tends to be proportionately wider. Consequently, the Ca l i f o r n i a n race d i f f e r s s i g n i f i c a n t l y from the Vancouver Island, Mule deer and Sitka deer i n the head length/head width and possibly also i n the hind leg length/hip width r a t i o s . I t i s concluded that c e r t a i n growth parameters, which d i f f e r for each comparison, are c h a r a c t e r i s t i c of each of the four races studied. I t i s , therefore, pos-s i b l e to separate each.stock on the basis of growth pat-terns when they are raised under i d e n t i c a l n u t r i t i o n a l conditions. The re s u l t s also indicate that physiological c h a r a c t e r i s t i c s pertaining to growth are s i f f i c i e n t l y established in: the two stocks of Columbian B l a c k - t a i l e d deer to permit their r a c i a l separation on the basis of some aspects of the i r growth patterns. 170 LITERATURE CITED Bailey, C. B., W. D. K i t t s and A. J . Wood. 1960. Changes i n the gross chemical composition of the mouse during growth i n r e l a t i o n to the assessment of physiological age. Can. J. Anim. S c i . 40(2):143-155. Bandy, P. J . 1955. 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I_n "Dynamics of Growth Processes" Ed. by E. J . B o e l l , pp. 242-276. Einarsen, A. S. 1946. Crude protein determination of deer food as an applied management technique. Trans. N. Am. Wildl. Conference 11:309-312. F e l l e r , W. 1940. On the l o g i s t i c law of growth and i t s empirical v e r i f i c a t i o n s i n biology. Acta Biotheoretica 5j 51-66. F i t t , A. B. 1941. Seasonal influence on growth, function and inheritance. Whitcombe 85 Tombs Ltd., N.Z. Hammond, J. 1932. Growth and development of mutton q u a l i -t i e s i n the sheep. Oliver and Boyd, Edinburgh. . 1950. Measuring growth i n farm animals. Proc. Roy. Soc. B, 137:452-461. . 1952. Farm animals. Their breeding, growth and inheritance. 2nd edi t i o n . Edward Arnold & Co., London. Hawk, P. B., B. L. Oser and W. H. Summerson. 1951. P r a c t i -c a l p hysiological chemistry. The Blakiston Co., Toronto. K i t t s , W. D., I. McT. Cowan, John Bandy and A. J. Wood. 1956. The immediate post-natal growth, i n the Colum-bian B l a c k - t a i l e d deer i n r e l a t i o n to the composition of the milk of the doe. J . Wildl. Mgmt. 20(2):212-214. Kleiber, M. 1933. Tiergrbsse und Futterverwertung. . Biedermanns Zentralbl. Agrikulturchem. Abt. B., 5 (1/2):1-12. Klein, D. R. 1957. Sex and age composition and physical condition,of deer i n the hunter take. Fed. Aid i n Wildl. Restoration, Alaska, Job Completion Reports Project W-3-R-11, Job No. 4, pp. 22-37. 172 Klein, D. R. 1959. Sex and age composition and physical condition of deer in. the hunter take. Federal Aid i n W i l d l . Restoration, Alaska, Job Completion Reports Vol. 13, No. 4j Job. No. 2, pp. 4-17. 1963. Physiological response of deer on ranges of varying quality. Ph.D. Thesis, Dept. of Zoology, University of B r i t i s h Columbia, Vancouver. 1964. Range-related differences i n growth of deer r e f l e c t e d i n s k e l e t a l r a t i o s . J. Mammal. 45(2): 226-235. Lewall, E.F. and I. McT. Cowan. 1963. Age determination i n B l a c k - t a i l e d deer by degree of o s s i f i c a t i o n of the epiphyseal plate i n the long bones. Can. J. Zool. 41: 629-636. Lutwak-Mann, C e c i l i a . 1951. Hormonal and n u t r i t i o n a l factors i n the metabolism of the male accessory organs of reproduction. Biochem. J . 48:lxiv. MacDonald, M. A. 1958. Seasonal growth relationships i n Aberdeen Angus X Jersey crossbred c a t t l e . N. Z. J. Agr. Res. 1(3):341-348. McMeekan, C. P. 1940a. Growth and development i n the pig, with s p e c i a l reference to carcass quality characters. I. J . Agr. S c i . 30:276-344. . 1940b. Growth and development i n the pig, with s p e c i a l reference to carcass quality characters. Part I I . The influence of the plane of n u t r i t i o n on growth and development. J . Agr. S c i . 30:387-426. . 1940c. Growth and development i n the pig, with s p e c i a l reference to carcass quality characters. Part I I I . E f f e c t of the plane of nutrition.on the form and composition of the bacon pig. J . Agr. S c i . 30:511-581. Medawar, P. B. 1945. Size, shape and age. In "Essays on growth and form". W. E. Le Gross and P. B. Medawar (Eds.), Clarendon Press, Oxford. Morgulus, S. 1913. The influence of protracted and i n t e r -mittent fa s t i n g upon growth.. Amer. Nat. 47:477-487. Morrison, F. B. 1956. Feeds and feeding, a handbook for the student and stockman. 22nd ed i t i o n . Morrison Publ. Co., Ithaca, N. Y. 173 Moulton, C. R., R. C. Trowbridge & L. D. Haid. 1921. Studies i n animal n u t r i t i o n . I. Changes i n form and weight on d i f f e r e n t planes of n u t r i t i o n . Univ. Missouri, Agr. Exp. Sta. Res. B u l l . , No. 43, 111 pp. Moustgaard, Johannes. 1959. Nu t r i t i o n and reproduction i n domestic animals. In "Reprod. i n Domestic Animals, I I I " , Cole, H. H. and C. T. Cupp (Eds.), Acad. Press, N. Y. O'Keefe, James John. 1957. Dry matter intake during early phases of growth for subspecies of deer (Odocoileus  hemionus). M. A. Thesis, Dept. of Zoology, University of B r i t i s h Columbia, Vancouver. Osborne, T. B. and L. B. Mendel. 1914. The suppression of growth and the capacity to grow. J . B i o l . Chem. 18:95-106. 1915. The resumption of growth after long con-tinued f a i l u r e to grow. J . B i o l . Chem. 23:439-454. Palsson, H. and J. B. Verges. 1952. E f f e c t s of the plane of n u t r i t i o n on growth and the development of carcass quality i n lambs: Part I. The ef f e c t s of high and low plane at d i f f e r e n t ages. J. Agr. S c i . 42:1—92. Part I I . E f f e c t on lamb of 30 pounds carcass weight. J. Agr. Sci. 42:93-149. Pearl, R. and L. J . Reed. 1923. On the mathematical theory of population growth. . Metron. 3_:6-19. Ricker, W. E. 1958. Handbook of computations for b i o l o g i -c a l s t a t i s t i c s of f i s h populations. Fisheries Res. Bd. Canada, B u l l . No. 119, Queen's Printer, Ottawa. Rowson, L. E. 1959. Libido i n the male. In "Reprod. i n Domestic Animals, I I " . Cole, H. H. and P. T. Cupps (Eds.), Acad. Press, N. Y. Snedecor, G. W. 1946. S t a t i s t i c a l methods. 4th edi t i o n . The Iowa State College Press, Ames, Iowa. Stewart, C. A. 1916. Growth of the body and the various organs of young Albino rats upon refeeding after i n a n i t i o n for various periods. Anat. Rec. (Proc.) 10:245-246. Walford, L i o n e l A. 1946. A new graphic method of des-c r i b i n g the growth of animals. B i o l . B u l l . 90(2):141-147. 174 Wood, A. J . , H. C. Nordan and I. Met. Cowan. 1961. The care and management of wild ungulates for experimental purposes. J . Wildl. Mgmt. 25(3):295-302. , I. McT. Cowan and H. C. Nordan. 1962. Per i o d i -c i t y of growth i n ungulates as shown by deer of the genus Odocoileus. Can. J. Zool. 40:593-603. A P P E N D I X 175 Table A Proximate Composition of U. B. C. Deer Ration #15-56 (From O'Keefe, 1957) Per 100 gms Wet Weight Per 100 gms Dry Weight Moisture Protein Fat Carbohydrate Fibre Ash 13.0 16.0 4.8 50.8 8.1 7.3 18.4 5.5 58.4 9.3 8.4 100.0 100.0 Gross Energy (Cal/oz) 1157 (Cal/lb) 1851.2 176 Table B Formulation for University of B r i t i s h Columbia Deer Ration #15-56 Constituent Pounds Per Ton Pounds Per 100 Corn; Meal Bran Beet Pulp (Ground) Molasses Ground Wheat Dehydrated A l f a l f a Meal Soybean Meal (50%) Copra Fish Meal (73%) Iodized Salt Bone Meal 600 275 200 150 250 200 100 75 110 20 20 2000 30.00 13.75 10.00 7.50 12.50 10.00 5.00 3.75 5.50 1.00 1.00 100.00 P e l l e t Size 12/64 inch Table C The cause of death of a l l deer which died p r i o r to reaching 1000 days of age Race Animal Sex Age at Cause No. Death Columbian 3 L M 93 Infectious white scours 5 L M 128 Ruptured urinary diver-B l a c k - t a i l ticulum 9 L M 49 Accidental (California) 10 L F 208 Ruptured bladder 13 L F 454 Accidental 18 L M 16 Pneumonia, f a i l e d to suckle 20 L M 185 Accidental 23 L F 197 Rumen malfunction Sitka Black-t a i l (Alaska) 31 L M 147 Pneumonia Columbian 52 L M 11 Infectious scours 54 L M 12 Infectious scours B l a c k - t a i l 57 L ?.. 10 Infectious scours 60 L F 86 Malnutrition, scours and (Vancouver unknown causes 62 L F 515 Accidental Island) 63 L M 92 Rumen malfunction and scours 64 L M 527 Malnutrition 65 L F 11 Accidental Mule Deer 91 L M 77 Pneumonia, rumen mal-function (Interior 93 L M 14 Infectious white scours 95 L F 8 Internal hemorrhage, B. C.) cause unknown 98 L F 65. Lindane poisoning 99 L ? 9 Infectious white scours 101 L F 189 Unknown 102 L M 569 Overdose of drug 103 L M 99 Rumen malfunction 106 L F 26 Infectious white scours 107 L F 9 Infectious white scours 108 L F 12 Infectious white scours 109 L F 10 Infectious white scours 110 L M 7 Infectious white scours 1.7^85 Table D Parameters for weight growth i n the formulation of the s e l f accelerating equation, W = Aekt for the e f f e c t i v e curve of growth Sex and Plane Deer 1 A of N u t r i t i o n No. In A k High plane males 1 2.49822 .011226 25 2.01777 .011998 30 1.65995 .0180&7 32 2.01959 .014167 38 2.39399 .014106 50 1.92226 .016513 51 1.70622 .016042 55 2.06866 .014709 59 2.11759 .011662 61 2.07860 .014816 90 2.13390 .018645 92 2.45001 .016412 94 2.27150 .016604 High plane females 21 2.20271 .013733 35 2.03538 .015448 37 1.91190 .018742 53 1.88235 .018372 56 2.11018 .015393 97 2.31248 .015972 Low plane males 19 1.87030 .014209 22 2.22507 .006931 33 2.07989 .012870 34 2.50851 .006074 36 2.52692 .005482 58 2.27822 .008554 104 2.60423 .008649 105 2.50700 .007821 Deer Numbers 1 - 25 - C a l i f o r n i a B l a c k - t a i l s 30 - 38 - Sitka B l a c k - t a i l s 50 - 62 - Vancouver Island B l a c k - t a i l s 90 - 105 - Mule Deer 179 Table E Parameters for weight growth i n the formulation of the s e l f -i n h i b i t i n g equation W = A - Be~ k* for the e f f e c t i v e curve of growth Sex and Plane Deer a -i „ — of N u t r i t i o n No. A In B — K High plane males 1 275 5.50278 .001239 25 215 5.15856 .001293 30 230 5.28102 .001044 32 290 5.71845 .001728 38 340 5.75642 .001084 50 215 5.40479 .002224 51 270 5.56052 .001112 55 270 5.51667 .000959 59 180 5.15303 .001631 90 295 5.78319 .002701 92 343 5.78010 .001919 High plane females 21 112 4.34580 .002330 35 130 4.82471 .003198 37 142 4.87565 .002587 53 135 4.70108 .002121 56 190 5.07029 .001323 97 190 5.31468 .004181 Low plane males 19 125 4.76677 .001612 22 126 4.95076 .002174 33 140 4.91716 .001632 34 135 4.79180 .001192 36 150 5.00763 .001451 58 125 4.77020 .001524 104 170 5.08752 .001418 105 190 5.26863 .001251 180 Table F Parameters for l i n e a r growth i n the formulation of the equa-tion L = A - Be~ kt f o r a l l deer studied Deer No. A -B -k SY k Rk 2 01 84.012 43.553 .00904 1.858 .978 25 89.021 53.115 .00517 1.706 .988 30 89.193 56.327 .00617 1.502 .993 32 101.593 64.763 .00484 1.955 .990 38 90.306 52.449 .00636 1.448 .989 50 88.290 52.693 .00636 2.014 .985 51 87.654 57.018 .00634 1.272 .994 55 89.190 51.401 .00615 1.242 .994 59 89.380 51.186 .00520 1.573 .990 61 94.465 56.167 .00591 1.591 .990 90 108.385 65.296 .00608 1.338 .995 92 104.022 63.177 .00793 2.390 .983 94 103.879 62.275 .00603 1.910 .990 102 106.228 65.762 .00600 1.350 .995 High plane males. Chest g i r t h . Deer No. A -B -k SY k Rk 2 01 78.859 47.403 .00688 2.113 .969 25 99.380 69.859 .00291 2.482 .982 30 83.914 58.017 .00479 2.813 .976 32 107.471 77.071 .00302 2.742 .983 38 92.227 62.110 .00494 3.237 .966 50 88.392 61.286 .00519 1.989 .989 51 88.427 65.538 .00478 1.891 .990 55 88.084 58.245 .00431 3.085 .970 59 88.385 59.874 .00371 2. 166 .985 61 104.562 72.284 .00309 3.898 .963 90 102.578 71.0.63 .00519 2.782 .983 92 97.439 67.975 .00619 4.275 .955 94 100.878 71.536 .00532 3.100 .981 102 102.823 74.313 .00505 3.663 .973 181 Table F (cont'd.) High plane males. Hind leg length. Deer No. A -B -k SYk *k 2 01 42.142 21.913 .00822 0.653 .984 25 44.117 22.494 .00542 0.803 .986 30 43.126 22.766 .00642 0.831 .987 32 46.249 24.272 .00580 0. 563 .994 38 44.921 21.240 .00629 0.882 .978 50 42.485 21.797 .00637 0.435 .996 51 43.478 23.738 .00558 0.421 .996 55 45.401 22.084 .00552 0.796 .987 59 44.951 22.485 .00519 0.732 .989 61 44.898 22.597 .00692 0.670 .991 90 53.390 26.952 .00617 0.913 .988 92 54.750 27.612 .00644 0.913 .987 94 50.901 25.751 .00712 1.130 .981 102 54.139 29.366 .00562 0.844 .991 High plane males. Head length. Deer No. A -B -k SY k R k2 01 26.958 14.043 .00847 0.618 .967 25 28.694 14.047 .00403 0.977 .946 30 29.223 14.645 .00473 1.093 .946 32 33.514 18.882 .00344 0.712 .983 38 29.916 14.737 .00550 1. 247 .916 50 30.891 15.842 .00458 0.665 .982 51 27.962 15.349 .00569 0.494 .988 55 26.720 12.056 .00648 0.633 .973 59 27.422 12.801 .00479 0.696 .971 61 28.022 14.210 .00610 0. 783 .971 90 33.326 18.120 .00563 0.673 .985 92 33.549 18.082 .00544 0.797 .977 94 32.248 16.935 .00500 0.973 .963 102 35.122 19.961 .00453 0.859 .978 182 Table F (cont'd.) High plane males. Head width. Deer No. A -B -k SY k Rk 2 01 26.692 14.854 .00275 0.950 .919 25 24.342 11.744 .00279 1.028 .899 30 21.128 9.147 .00543 0.579 .962 32 25.444 13.053 .00316 0.940 . 937 38 ,22.067 9.397 .00700 0.544 .957 50 23.654 11.182 .00350 1.066 .911 51 20.278 9.739 .00790 0.703 .946 55 20.449 9.122 .00812 0.900 .912 59 20.117 8.342 .00643 0.749 .930 61 23.937 11.160 .00317 1.041 .898 90 24.545 11.082 .00445 0.708 .954 92 22.170 10.319 .00760 0.969 .906 ,94 21.641 10.908 .01038 1.016 .896 102 23.476 10.856 .00473 0.915 .922 High plane males. Hip width. Deer No. A -B -k SY k Rk 2 01 19.162 11.189 .00795 0.645 .946 25 22.822 14.509 .00323 0.802 .956 30 18.754 12.009 .00682 0.548 .980 32 19.857 12.429 .00533 0.512 .982 38 19.209 11.062 .00700 0.611 .959 50 18.172 11.265 .00736 0.400 ;988 51 18.468 •12.131 .00599 0.388 .988 55 17.564 9.735 .00644 0.408 .982 59 20.574 12.557 .00336 0.416 .985 61 19.774 12.215 .00570 0.482 .984 90 22.587 14.676 .00573 0.767 .972 92 22.113 13.528 .00636 0.685 .970 94 21.903 13.687 .00644 0.618 .979 102 25.039 16.969 .00422 0.669 .981 183 Table F (cont'd.) High plane females. Height-at-withers. • No. A -B -k SY k *k 2 02 77.604 49.518 .01047 1.482 .985 04 79.632 46.600 .00870 1.000 .993 07 78.408 45.927 .00949 1.938 .977 08 80.427 45.883 .00700 2.285 .972 12 71.403 35.072 .01022 1.663 .979 13 74.372 44.957 .01040 0.799 .995 21 76.778 37.692 .006 23 2.168 .967 35 83.953 46.920 .00734 1.914 .983 37 81.832 47.687 .00819 1.669 .987 53 81.681 44.332 .00848 1.619 .987 56 76.078 42.859 .01117 1.292 .987 62 87.997 50.259 .00584 1.016 .995 97 97.448 55.740 .00777 1.033 .994 High plane females. Chest g i r t h . Deer No. A -B -k SY t R t 2 02 69.235 42.339 .00864 1.643 .977 04 77.275 46.549 .00599 1.585 .982 07 76.728 48.995 .00633 1.217 .991 08 81.976 53.305 .00455 1.587 .986 12 84.304 48.213 .00250 3.638 .930 13 68.140 41.950 .00868 1.847 .974 21 86.603 51.752 .00217 1.814 .978 35 73.281 44.249 .00671 2.404 .972 37 85.865 56.676 .00481 2.270 .983 53 76.395 49.532 .00628 2.771 .972 56 90.235 58.039 .00395 3.753 .954 62 79.575 52.061 .00550 2.006 .985 97 99.406 67.919 .00505 2.099 .990 184 Table F ( cont'd.) High plane females. Hind leg length. Deer No. A -B -k SY k R k 2 02 39.668 18.971 .00822 0.681 .980 04 39.471 18.794 .00858 0.469 .991 07 39.496 18.235 .00854 0.552 .988 08 40.721 19.946 .00668 0.733 .984 12 37.338 16.055 .01002 0.571 .988 13 38.739 19.001 .00753 0.648 .984 21 40.277 16.954 .00513 0.834 .976 35 44.651 20.608 .00622 0.518 . 993 37 40.511 18.866 .00922 0.664 .987 53 40.670 18.704 .00793 0.523 .992 56 39.443 16.392 .00931 0.875 .971 62 41.759 19.465 .00661 0.544 .992 97 49.077 23.948 .00722 0.443 .996 High plane females. Head length. Deer No. A -B -k S Y k Rk 2 02 25.073 11.924 .01035 0.452 .976 04 25.534 11.073 .00677 0.548 .964 07 26.329 12.251 .00588 0.648 .961 08 28.178 14.110 .00529 0.593 .976 12 24.992 10.045 .00567 0.697 .960 13 24.019 11.456 .00927 0.546 .969 21 25.262 10.885 .00436 0.318 .990 35 28.214 13.219 .00561 0.785 .965 37 28.159 13.226 .00600 0.567 .982 53 27.345 12.993 .00570 0.696 .973 56 26.790 11.959 .00643 0.578 .977 62 28.749 14.011 .00415 0. 590 .980 97 28.728 13.394 .00733 0.924 .951 185 Table F (cont'd.) High plane females. Head width. Deer No. A -B -k SY k Rk 2 02 19.524 8.638 .00667 0.666 .914 04 18.984 7.560 .00838 0.539 .930 07 18.794 7.957 .00826 0.662 .916 08 20.202 8.667 .00679 0.708 .927 12 17.479 6.884 .01153 0.547 .942 13 18.203 7.130 .01033 0.771 .853 21 17.622 5.482 .00720 0.630 .886 35 19.344 7.585 .00933 0.749 .910 37 19.372 7.721 .01000 0.815 .895 53 19.223 7.453 .00919 1.015 .854 56 18.523 8.020 .01347 0.714 .913 62 18.875 7.343 .01000 0.628 .939 97 20.011 7.954 .01183 0.925 .866 High plane females. Hip width. Deer No. A -B -k S Y k Rk 2 02 17.448 10.933 .01013 0.468 .970 04 17.561 9.355 .00790 0.412 .972 07 18.067 10.856 .00636 0.275 .991 08 18.102 11.083 .00669 0.526 .974 12 16.241 7.977 .00700 0.564 .958 13 16.334 9.482 .00911 0.426 .972 21 19.866 11.353 .00278 0.442 .975 35 18.940 11.236 .00636 0.462 .983 37 18.731 11.585 .00718 0.370 .989 53 17.692 10.633 .00810 0.439 .984 56 fi 9 17.290 9.900 .00860 0.490 .975 97 21.026 12.897 .00635 0.741 .958 186 Table F (cont'd.) Low plane males. Height-at-withers Deer No. A -B -k SY k R k 2 19 75.044 38.421 .00718 1.342 .988 22 81.751 41.722 .00302 1.474 .979 33 79.521 43.216 .00644 1.790 .982 34 80.711 44.980 .00600 2.026 . 980 36 77.406 40.101 .00602 1.711 .982 58 94.009 48.270 .00291 1.470 .984 64 78.896 40.078 .00481 1.897 .977 104 85.652 40.628 .00634 2.055 .976 105 93.352 46.286 .00301 1.496 .984 Low plane males. Chest g i r t h . Deer No. A -B -k SY k R k 2 19 83.083 50.135 .00240 2.231 .969 22 78.859 52.538 .00281 1.103 .989 33 86.818 53.919 .00219 2.823 .953 34 93.362 61.297 .00210 2.658 .966 36 98.717 66.397 .00169 2.779 .960 58 ; 75.610 44.459 .00328 1.033 .992 64 68.043 39.999 .00465 1.195 .990 104 108.359 71.526 .00167 2.346 .975 105 78.798 42.358 .00331 1.501 .982 Low plane males. Hind leg length. Deer No. A -B -k SY k Rk 2 19 39.843 17.832 .00576 0.650 .987 22 48.863 25.715 .00223 0.697 .987 33 43.371 20.449 .00480 0.711 .987 34 41.138 18.817 .00568 0.857 .980 36 42.444 19.824 .00412 1.169 .964 58 48.997 23.954 .00254 0.607 .990 64 42.130 19.606 .00425 0.806 .981 104 46.477 20.119 .00537 0.888 .981 105 59.924 31.912 .00166 1.110 .971 187 Table F (cont'd.) Low plane males. Head length. Deer No. A -B -k SYk Rk 2 19 28.735 13.023 .00266 0.636 .966 22 31.130 15.412 .00189 0.553 .974 33 26.106 11.236 .00500 0.403 .986 34 30.232 14.918 .00306 0.445 .988 36 32.368 16.449 .00203 0.676 .969 58 27.291 12.253 .00371 0.410 .987 64 26.802 11.704 .00380 0.433 .983 104 34.422 16.901 .00194 0.572 .978 105 29.917 12.945 .00245 0.885 .930 Low plane males. Head width. Deer No. A -B -k SY k »k 2 19 19.587 7.486 .00500 0.561 .947 22 21.012 8.237 .00370 0.623 .936 33 18.920 7.964 .01060 0.662 .931 34 19.902 7.168 .00667 0.514 .953 36 19.656 6.280 .00500 0.699 .890 58 19.551 7.129 .00522 0.638 .926 64 18.588 7.177 .00810 0.536 .953 104 25.364 11.012 .00185 1.156 .805 105 26.916 .13; 015 .00181 0.945 .893 Low plane males. Hip width. Deer No. A -B -k SY k Rk 2 19 17.312 9.046 .00488 0.256 .991 22 20.152 12.640 .00235 0.226 .991 33 1.6.286 8.416 .00571 0.324 .984 34 16.031 8.695 .00663 0.352 .984 36 15.596 8.194 .00614 0.403 .977 ^58 19.535 10.836 .00229 0.253 .989 64 15.964 8.369 .00460 0.380 .978 104 18.584 9.697 .00305 0.366 .979 105 20.266 10.921 .00179 0.388 .968 188 Table F (cont'd.) Low plane females. Height-at-withers. Dber No. A -B -k SY k R k2 06 77.019 40.022 .00713 1.361 .985 15 77.413 41.670 .01049 0.910 .994 96 89.708 50.440 .00492 1.960 .983 Low plane females. Chest g i r t h . Deer No. A -B -k SY k R 2 K k 06 66.409 36.779 .00574 0.951 .990 15 74.200 44.183 .00697 1.931 .981 96 82.935 53.528 .00354 1.063 .994 Low plane females. Hind leg length. Deer No. A -B -k SY k R k2 06 40.097 17.672 .00665 0.385 ;993 15 42.165 20.836 .00816 0.860 .983 96 46.774 23.424 .00445 0.695 .989 Low plane females. Head length. Deer No. A -B -k SY k R k 2 06 23.734 9.237 .00774 0.742 . 926 15 28.045 13.304 .00560 0.859 .959 96 28.529 13.382 .00463 0.483 .985 189 Tables F (cont'd.) Low plane females. Head width. Deer No. A -B -k SY k R k2 06 18.371 6.655 .00771 0.623 .902 15 19.098 7.406 .00854 0.674 .922 96 19.578 7.119 .00 743 0.324 .980 Low plane females. Hip Width. Deer No. A -B -k SY k Rk 2 06 17.233 9.045 .00606 0.371 .977 15 17.894 9.776 .00700 0.494 .974 96 19.761 12.283 .00360 0.371 .988 

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