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Genetic influence on seven week body weight of pre-and post-hatching growth rates in the chicken Phalaraksh, Kanok 1972

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cf THE GENETIC INFLUENCE ON SEVEN WEEK BODY WEIGHT OF PRE- AND POST-HATCHING GROWTH RATES IN THE CHICKEN by KANOK PHALARAKSH B.Sc. (Hons.) K a s e t s a r t U n i v e r s i t y , T h a i l a n d , 1967 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n the Department of P o u l t r y Science We accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA August, 1972 In present ing th i s thes is in pa r t i a l f u l f i lmen t o f the requirements for an advanced degree at the Un ive rs i t y of B r i t i s h Columbia, I agree that the L ib ra ry sha l l make it f r ee l y ava i l ab le for reference and study. I fu r ther agree that permission for extensive copying o f th i s thes i s for s cho la r l y purposes may be granted by the Head of my Department or by h is representa t i ves . It is understood that copying or pub l i c a t i on o f th is thes i s fo r f i nanc ia l gain sha l l not be allowed without my wr i t ten permiss ion. Kanok Phalaraksh Department of Poultry Science The Un ivers i t y of B r i t i s h Columbia Vancouver 8, Canada Date August 30, 19 72. ABSTRACT A t o t a l of 7,472 progeny from 4 l i n e s of c h i c k e n s , a Black A u s t r a -l o r p , a New Hampshire and 2 Leghorn l i n e s , t h e i r crosses and r e c i p r o c a l crosses were assessed f o r t h e i r p re- and pos t - h a t c h i n g body w e i g h t s , pre-and p o s t - h a t c h i n g growth r a t e s and t h e i r a s s o c i a t e d egg w e i g h t s . The i n t e r r e l a t i o n s h i p s of these t r a i t s as they i n f l u e n c e d growth and 7-week body weight were e v a l u a t e d . The e f f e c t s of these r e l a t i o n s h i p s were j o i n t l y considered as they i n f l u e n c e d the genetic v a r i a t i o n and subsequent 2 estimates of the h e r i t a b i l i t y (h ) of these t r a i t s . The r e s u l t s of the i n v e s t i g a t i o n showed th a t an adverse e n v i r o n -mental e f f e c t due to h a t c h i n g was d e f i n i t e l y e s t a b l i s h e d . I t took 2 weeks of growth a f t e r h a t c h i n g f o r the chicken body weights to a t t a i n the same l e v e l of a s s o c i a t i o n w i t h 7-week body weight that was p r e v i o u s l y shown i n the body weights of 18-day o l d embryos. M u l t i p l e r e g r e s s i o n analyses showed t h a t 1-week body weight and any subsequent growth pe r i o d s 2 s u c c e s s f u l l y accounted f o r v a r i a t i o n i n 7-week body weigh t . The h estimates obtained f o r a l l weekly growth r a t e s as w e l l as the 1-3, 3-7, and 1-7 week growth r a t e s s t r o n g l y i n d i c a t e d a major source of a d d i t i v e g e n e t i c v a r i a n c e was a v a i l a b l e i n p o u l t r y populations that h e r e t o f o r e has not been d i r e c t l y u t i l i z e d i n body weight s e l e c t i o n programs. i i TABLE OF CONTENTS Page INTRODUCTION . . . 1 REVIEW OF THE LITERATURE . 2 MATERIALS AND METHODS . 15 STATISTICAL METHODS . . . . . . . 19 RESULTS AND DISCUSSION . „ 25 Embryo Weights 25 Embryo Growth Rates . . . . . . . . . 38 Post-hatching Body Weights . . . . . . 57 Post-hatching Growth Rates 72 Pre- and Post-storage Egg Weights . 95 Embryo Cor re l a t i ons -^04 Post-hatching Cor re l a t ions , 106 Cor re l a t i ons of Embryo and Post-hatching Data 109 H e r i t a b i l i t y of Embryo Weights . 129 H e r i t a b i l i t y of Post-hatching data 131 SUMMARY . 141 BIBLIOGRAPHY . . 145 APPENDIX • . . . . 151 i i i LIST OF TABLES Table Page 1 Expected Mean Squares f o r the A n a l y s i s of Body Weights and Growth Rates of P r e - and Post-hatch Chick Data 21 2 A n a l y s i s of Variance f o r the C a l c u l a t i o n of H e r i t a b i l i t y Estimates on the P r e - and Post-Hatch Chick Data 24 3 Mean Embryo Weights at Two Day I n t e r v a l s Across R e p l i c a t i o n s from 6 to 18 Days of Incubation f o r Male and Female Progeny 26 4 Sums of Squares from the A n a l y s i s of Variance of 6-Day Embryo Weights, C a l c u l a t i o n s Based on C e l l Means ..... 28 5 Sums of Squares from the Analyses of Variance of Mean Embryo Weights at Two Day I n t e r v a l s from 8 t o 18 days of I n c u b a t i o n , C a l c u l a t i o n s Based on D i a l l e l C e l l Means 29 6 Mean Embryo Weights of Males and Females By R e p l i c a t i o n 31 7 Sums of Squares from the Analyses of Variance of Mean Embryo Weights of Male Progeny at Two Day I n t e r v a l s from 8 to 18 Days o f Incubation 32 8 S i r e and Dam L i n e Mean Embryo Weights of Male Progeny from 8 to 18 Days o f Incubation 33 9 Sums of Squares from the Analyses of Variance of Mean Embryo Weights of Female Progeny at Two Day I n t e r v a l s from 8 to 18 Days of Incuba- 35 t i o n 10 S i r e and Dam Li n e Mean Embryo Weights of Female Progeny from 8 to 18 Days of Incubation 36 i v - v -Table Page 11 Mean Embryo Growth Rates a t Two Day I n t e r v a l s A c r o s s R e p l i c a t i o n s from 6 to 18 Days of I n c u b a t i o n f o r Male and Female Progeny 39 12 Sums of Squares from the A n a l y s e s of V a r i a n c e of Mean Embryo Growth Rates a t Two Day I n t e r v a l s from 6 t o 18 Days of I n c u b a t i o n , C a l c u l a t i o n s Based on D i a l l e l C e l l Means 40 13 Mean Embryo Growth Rates of Males and Females by R e p l i c a t i o n . . . . . 42 14 Sums o f Squares from the A n a l y s e s of V a r i a n c e of Mean Embryo Growth Rates of Male Progeny a t Two Day I n t e r v a l s f rom 6 to 18 Days of I n c u b a t i o n 43 15 S i r e and Dam L i n e Mean Embryo Growth Rates o f Male Progeny a t Two Day I n t e r v a l s f rom 6 t o 18 Days of I n c u b a t i o n . . . . . 45 16 Sums o f Squares from the A n a l y s e s o f V a r i a n c e o f "Mean Embryo Growth Rates of Female Progeny a t Two Day I n t e r v a l s f rom 6 to 18 Days of I n c u b a t i o n 46 17 S i r e and Dam L i n e Mean Embryo Growth Rates o f Female Progeny a t Two Day I n t e r v a l s from 6 to 18 Days of I n c u b a t i o n 47 18 Sums o f Squares f rom the A n a l y s e s of V a r i a n c e of Mean Embryo Growth Rates f o r V a r y i n g Growth P e r i o d s , C a l c u l a t i o n s Based on D i a l l e l C e l l Means 49 19 Mean Embryo Growth Rates of Males and Females by R e p l i c a t i o n 50 20 Sums o f Squares from the A n a l y s e s of V a r i a n c e of Mean Male Embryo Growth Rates f o r V a r y i n g Growth P e r i o d s 52 21 S i r e and Dam L i n e Mean Embryo Growth Rates of Male Progeny f o r V a r y i n g Growth P e r i o d s from 8 to 18 Days of I n c u b a t i o n 53 - v i -Table Page 22 Sums of Squares from the Analyses of Variance of Mean Female Embryo Growth Rates f o r V a r y i n g Growth Per i o d s 55 23 S i r e and Dam Mean Embryo Growth Rates o f Female Progeny f o r Varying Growth Periods from 8 to 18 -Days of Incubation 56 24 Mean Chick Body Weights of Males and Females at Weekly I n t e r v a l s from Hatch to 7 Weeks of Age Across R e p l i c a t i o n s 58 25 Sums of Squares from the Analyses of Variance of Mean Chick Body Weights from Hatch to 7 Weeks of Age, C a l c u l a t i o n s Based on D i a l l e l C e l l Means 59 26 Mean Chick Body Weights of Male and Female Progeny by R e p l i c a t i o n ^1 27 Sums of Squares from the Analyses o f Variance of Mean Male Progeny Weights at Weekly I n t e r v a l s from Hatch t o 7 Weeks of Age 62 28 S i r e and Dam L i n e Mean Body Weights of Male P r o -geny from Hatch to 7 Weeks of Age 64 29 S i r e , Dam and S i r e X Dam I n t e r a c t i o n E f f e c t s on the Body Weights of Male Progeny 66 30 Sums of Squares from the Analyses of Variance of Mean Body Weights of Female Progeny at Weekly I n t e r v a l s from Hatch to 7 Weeks of Age 69 31 S i r e and Dam L i n e Mean Body Weights of Female Progeny from Hatch to 7 Weeks of Age 71 32 S i r e , Dam and S i r e X Dame I n t e r a c t i o n E f f e c t s on the Body Weights of Female Progeny 73 33 Mean Chick Growth Rates of Males and Females at Weekly I n t e r v a l s Across R e p l i c a t i o n s from Hatch to 7 Weeks of Age 76 34 Sums of Squares from the Analyses of Variance of Mean Chick Weekly Growth Rates from Hatch to 7 Weeks of Age, C a l c u l a t i o n s Based on D i a l l e l C e l l Means 7 8 - vii -Table N Page 35 Mean Chick Growth Rates of Male and Female Progeny by Replication 79 36 Sums of Squares from the Analyses of Variance of Weekly Growth Rates of Male Progeny from Hatch to 7 Weeks of Age 81 37 Sums of Squares from'the Analyses of Variance of Weekly Growth Rates of Female Progeny from Hatch to 7 Weeks of Age 82 38 Sire and Dam Line Mean Growth Rates of Male Progeny During Weekly Intervals from Hatch to 7 Weeks of Age 84 39 Sire and Dam Line Mean Growth Rates of Female Progeny During Weekly Intervals from Hatch to 7 Weeks of Age 85 40 Mean Chick Growth Rates of Males and Females for Varying Growth Periods Across Replications 87 41 Sums of Squares from the Analyses of Variance of Chick Growth Rates for Varying Growth Periods, Calculations Based on D i a l l e l Cell Means 88 42 Mean Chick Growth Rates of Male and Female Progeny by Replication 90 43 Sums of Squares from the Analyses of Variance of Male Progeny for Varying Growth Periods 91 44 Sums of Squares from the Analyses of Variance of Female Progeny for Va??ying Growth Periods 92 45 Sire and Dam Line Mean Growth Rates of Male Progeny for Varying Growth Periods 94 46 Sire and Dam Line Mean Growth Rates of Female Progeny for Varying Growth Periods 96 47 Mean Pre- and Post-Storage Egg Weights for the Hatched Progeny of Each Sire and Dam Line 97 - v i i i -Table Page 48 Sums of Squares from the Analyses of Variance of Pre- and Post-Storage Egg Weights f o r Hatched Progeny 99 49 Analyses of Variance of Mean Egg Weights T e s t i n g the Storage E f f e c t 100 50 Mean Pre- and Post-Storage Egg Weights by R e p l i -c a t i o n fcr Hatched Progeny ..... 102 51 S i r e , Dam and S i r e X Dam I n t e r a c t i o n E f f e c t s on the Pre- and Post-storage Egg Weights 103 52 Simple C o r r e l a t i o n C o e f f i c i e n t s o f Pre- and Post-Storage Egg Weights w i t h Embryo Weights W i t h i n Each Sex and R e p l i c a t i o n , C a l c u l a t i o n s Based on I n d i v i d u a l Data 105 53 Simple C o r r e l a t i o n C o e f f i c i e n t s of Pre- and Post-storage Egg Weights w i t h Chick Body Weights and Growth Rates w i t h i n Each Sex and R e p l i c a t i o n , C a l c u l a t i o n s Based on I n d i v i d u a l Data 1^7 54 Simple C o r r e l a t i o n C o e f f i c i e n t s of Chick Growth Rates w i t h Embryo Growth Rates W i t h i n Sex and R e p l i c a t i o n , C a l c u l a t i o n s Based on D i a l l e l C e l l Means (Male, R e p l i c a t i o n 1) HO 55 Simple C o r r e l a t i o n C o e f f i c i e n t s of Chick Growth Rates w i t h Embryo Growth Rates W i t h i n Sex and R e p l i c a t i o n , C a l c u l a t i o n Based on D i a l l e l C e l l Means (Female, R e p l i c a t i o n 1) ..... m 56 Simple C o r r e l a t i o n C o e f f i c i e n t s of Chick Growth Rates w i t h Embryo Growth Rates W i t h i n Sex and R e p l i c a t i o n , C a l c u l a t i o n s Based on D i a l l e l C e l l Means (Male, R e p l i c a t i o n 2) 57 Simple C o r r e l a t i o n C o e f f i c i e n t s of Chick Growth Rates and Embryo Growth Rates W i t h i n Sex and R e p l i c a t i o n , C a l c u l a t i o n s Based on D i a l l e l C e l l Means (Female, R e p l i c a t i o n 2) ^ 3 - i x -Table Page 58 Simple C o r r e l a t i o n C o e f f i c i e n t s of 7 Week Body Weights w i t h Embryo Weights and Chick Weights W i t h i n Each Sex and R e p l i c a t i o n ..... H 8 59 Simple C o r r e l a t i o n C o e f f i c i e n t s of 7 Week Body Weights w i t h Embryo Growth Rates and Chick Growth Rates w i t h i n Each Sex and R e p l i c a t i o n 120 2 60 C o e f f i c i e n t s of Determination (100 X R ) of I n d i v i d u a l Estimates of 7 Week Body Weights W i t h i n Each Sex and R e p l i c a t i o n M u l t i p l e Re-gressed on Se l e c t e d T r a i t s 123 2 61 C o e f f i c i e n t s of Determination (100 X R ) of Hatching Weights M u l t i p l e Regressed on Selec t e d T r a i t s 126 2 62 C o e f f i c i e n t s of Determination (100 X R ) of 1-Week Body Weights M u l t i p l e Regressed on Sel e c t e d T r a i t s 128 63 H e r i t a b i l i t y Estimates of Embryo Weights, C a l c u l a t i o n s Based on Separated Sex i n Each R e p l i c a t i o n . 130 64 H e r i t a b i l i t y Estimates and Standard E r r o r of Egg Weights, Chick Growth Rates and Body Weights ( R e p l i c a t i o n 1) 132 65 H e r i t a b i l i t y Estimates and Standard E r r o r of Egg Weights, Chick Growth Rates and Body Weights ( R e p l i c a t i o n 2) ..... I3 3 66 H e r i t a b i l i t y Estimates of Egg Weights, Chick Growth Rates and Body Weights, C a l c u l a t i o n s Based on the Averages Across R e p l i c a t i o n s 13^ ACKNOWLEDGEMENT The author i s very g r a t e f u l to Dr. C.W. Roberts who provided s u p e r v i s i o n , suggestions and f a c i l i t i e s f o r t h i s study. He would a l s o l i k e to express h i s a p p r e c i a t i o n to Mr. C.J. W i l l i a m s and Dr. R.G. Peterson f o r t h e i r Least-squares a n a l y s i s computer program. The author wishes to express h i s g r a t i t u d e to those members of the F a c u l t y who read the manuscript and o f f e r e d t h e i r a d v i c e . A p p r e c i a -t i o n i s a l s o expressed f o r the a s s i s t a n c e g i v e n by f e l l o w students and the t e c h n i c a l s t a f f . T h i s t h e s i s could not have been undertaken without the f i n a n c i a l a s s i s t a n c e of Canadian government. In p a r t i c u l a r , the author wishes to thank the Canadian I n t e r n a t i o n a l Development Agency. x INTRODUCTION i The gen e t i c and environmental i n f l u e n c e of e a r l y growth r a t e on subsequent body weight performance i n the growing chicken i s not w e l l d e f i n e d . G e n e t i c i s t s have used body weight at a given age as the s o l e c r i t e r i a of s e l e c t i o n to improve body weight i n b r o i l e r s t o c k . The con-sequence of such s e l e c t i o n has tended to i n c r e a s e egg s i z e and lower egg p r o d u c t i o n . T h i s i s due t o the negative g e n e t i c c o r r e l a t i o n e x i s t i n g between these t r a i t s . Recent work by Deland (1965) i n v e s t i g a t e d the power f u n c t i o n (y = a t ^ ) , proposed by Roberts (1964), as a method by which the growth r a t e (b) could be measured g e n e t i c a l l y . Deland compared the p r e - and post-h a t c h i n g growth pe r i o d s and found a strong i n d i c a t i o n t h a t growth r a t e could be i n c o r p o r a t e d s u c c e s s f u l l y i n t o a s e l e c t i o n program f o r improving body weight. The purpose of t h i s present study was to determine the g e n e t i c worth of the growth r a t e measurement i n a l a r g e p o p u l a t i o n and to show i t s a s s o c i a t i o n w i t h other p o p u l a t i o n parameters. - 1 -REVIEW OF THE LITERATURE Halbersleben and Mussehl (1922) showed there was a c o n s i s t e n t r e l a t i o n s h i p between the weight of the egg used f o r h a t c h i n g and the weight of the c h i c k at h a t c h . The c h i c k weight averaged 64 percent of the egg weight. However, at 35 days of age any apparent advantage possessed by c h i c k s hatched from l a r g e eggs, had n e a r l y disappeared. Wiley (1950 b) found t h a t s m a l l eggs used f o r hatching gave the c h i c k s a decided body weight disadvantage a t h a t c h i n g . T h i s disadvantage was l a r g e l y overcome by the t w e l f t h week. There was no constant s i g n i f i c a n t d i f f e r e n c e i n f e a t h e r -i n g r a t e , m o r t a l i t y , or h a t c h a b i l i t y i n favour of e i t h e r egg weight groups. Godfrey et a l . (1953) s t u d i e d phenotypic c o r r e l a t i o n s of the dam egg s i z e , age at sexua l m a t u r i t y , and a d u l t body weight w i t h bi-weekly weights of i n d i v i d u a l s to 12 weeks of age and i n d i c a t e d t h a t the i n f l u e n c e of egg s i z e on e a r l y growth decreases r a p i d l y a f t e r 2 weeks of age and has no a p p r e c i a b l e e f f e c t on weight at b r o i l e r age. They found t h a t the combined i n f l u e n c e of egg weight, age at sexual m a t u r i t y and a d u l t body weight accounted f o r about 36 percent of the v a r i a t i o n observed i n body weight at 12 weeks of age. Less of the observed v a r i a t i o n i n body weight was accounted f o r by these f a c t o r s a t 2, 4, 6, 8 and 10 weeks of age. At ha t c h i n g however, due to the r e l a t i v e l y l a r g e i n f l u e n c e of egg s i z e , these three f a c t o r s accounted f o r about 74 percent of the observed v a r i a t i o n i n body weight. - 2 -Upp (1928) concluded that egg weight and c h i c k weight at hatching were h i g h l y c o r r e l a t e d (r = 0.79) but that n e i t h e r o b s e r v a t i o n formed a r e l i a b l e index of c h i c k weight at 2, 4 or 12 weeks of age. J u l l and Heywang (1930) found the percent y o l k weight of c h i c k weight at h a t c h i n g time was independent of the sex of the c h i c k . They a l s o showed t h a t the percent c h i c k weight of i n i t i a l egg weight was independent of i n i t i a l egg weight, i . e . - r e g a r d l e s s of the i n i t i a l egg weight the percent c h i c k weights tended t o be the same. Y o l k m a t e r i a l formed about 18 percent of c h i c k weight at h a t c h and the c o r r e l a t i o n of egg and embryo weights i n c r e a s e d d u r i n g y o l k a s s i m i l a t i o n . O'Neil (1950) used two hatches of Barred Plymouth Rock c h i c k s to t e s t the e f f e c t of percent s i z e of c h i c k on growth c h a r a c t e r i s t i c s and m o r t a l i t y to 8 weeks of age. The r e s u l t s i n d i c a t e d t h a t f o r both sexes those c h i c k s hatching w i t h the highest percentage of the o r i g i n a l weight of the egg were h e a v i e r at 8 weeks of age, more e f f i c i e n t i n feed consumption and had a lower r a t e of m o r t a l i t y . He mentioned that there was a s i g n i f i -cant d i f f e r e n c e i n sex r a t i o s f a v o u r i n g the males i n the group that had the l a r g e r percentage of the o r i g i n a l egg weight and f a v o u r i n g the females i n the other group. Chicks from l a r g e eggs had a s l i g h t advantage i n growth r a t e when compared to c h i c k s from small eggs (Kosin et^ a]L., 1952). Skoglund et al.(1952) i n d i c a t e d t h a t c h i c k s from l a r g e r eggs were h e a v i e r at 12 weeks of age when a l l b i r d s were reared together. Goodwin (1961) u s i n g r e g r e s s i o n a n a l y s e s , s t u d i e d the r e l a t i o n s h i p between ha t c h i n g w e i g h t , - 4 -egg s i z e , chick s i z e , and growth r a t e to f r y e r age. He suggested that the s i z e of a chick at h a t c h i n g had an important e f f e c t on i t s growth to b r o i l e r age, even though the s m a l l e r c o r r e l a t i o n of 9 week weight w i t h egg w e i g h t , as compared w i t h the c o r r e l a t i o n of h a t c h i n g weight w i t h egg weight had been i n t e r p r e t e d p r e v i o u s l y as b e i n g i n s i g n i f i c a n t . C o n t r a r i l y , Godfrey et a l . , (1953) as mentioned b e f o r e , and Pope and S c h a i b l e (1957) concluded th a t the e f f e c t of egg s i z e on e a r l y growth decreased r a p i d l y a f t e r the f i r s t few weeks of age and had no a p p r e c i a b l e e f f e c t on weight at b r o i l e r age. However, they mentioned t h a t the above r e l a t i o n s h i p might not h o l d true f o r a l l breeds and s t r a i n s . T i n d e l and M o r r i s (1964) found d i f f e r e n c e s i n favour of the h e a v i e r egg weight groups f o r percent f e r t i l i t y , percent h a t c h a b i l i t y of t o t a l eggs s e t , and body weight. E s s e n t i a l l y , no d i f f e r e n c e was present f o r percent hatch of f e r t i l e eggs, percent m o r t a l i t y and percent condemnation. Egg weight groups, when i n t e r m i n g l e d , tended to have g r e a t e r t o t a l m o r t a l i t y and weigh l e s s at a given age as compared to the same egg weight groups penned and reared s e p a r a t e l y . Godfrey and W i l l i a m s (1955) used the weights of the day-old c h i c k as a percentage of o r i g i n a l egg weight (719 New Hampshire c h i c k s ) to p r e d i c t body weight at 12 weeks of age. Only about 5 percent of the t o t a l v a r i a t i o n i n 12-week body weight could be accounted f o r by the percent the day-old chick was of the o r i g i n a l egg weight; thus, t h i s r a t i o was of p r a c t i c a l l y no value i n p r e d i c t i n g growth r a t e . Bray and I t o n (1962) s t u d i e d embryonic and e a r l y c h i c k growth i n r e l a t i o n to egg weight i n 5 s t r a i n s of domestic f o w l , and demonstrated that - 5 -the s i z e of the egg can be regarded as a temporary environmental i n f l u e n c e which masked the d i f f e r e n c e s among s t r a i n s . This e f f e c t apparently began a f t e r 11 days of i n c u b a t i o n i n t h e i r s t o c k , and increased g r a d u a l l y to a maximum at h a t c h i n g time when egg s i z e almost completely determined chick s i z e . The e f f e c t r a p i d l y decreased as the chicks became o l d e r . The i n f l u e n c e of breed and s t r a i n upon the growth of the embryo has been s t u d i e d by many i n v e s t i g a t o r s . Henderson (1930) analyzed the data from the U n i v e r s i t y of I l l i n o i s s t r a i n of pure bred S i n g l e Comb White Leghorns and from pure bred Dark C o r n i s h . No s i g n i f i c a n t d i f f e r e n c e s be-tween the embryo weights of the two breeds and t h e i r r e c i p r o c a l crosses could be d e t e c t e d . B y e r l y (1930) demonstrated that crosses gave a s l i g h t d i f f e r e n c e i n s i z e of embryos at the same stage of i n c u b a t i o n , from eggs of the same s i z e , but these d i f f e r e n c e s disappeared at h a t c h i n g . I n a l a t e r study ( B y e r l y , 1922) noted t h a t each embryo had an inherent growth r a t e which was modified p r o p o r t i o n a l l y to d i f f e r e n c e s i n the immediately a v a i l a b l e food s u p p l y , i . e . a f u n c t i o n of egg s i z e . Blunn and Gregory (1955) found that a study of weights alone d i d not r e v e a l d i f f e r e n c e s i n embryonic development r a t e between White Leghorn and Rhode I s l a n d Reds, but a study of c e l l s i z e , number and r a t e of m i t o s i s showed that d i f f e r e n c e s e x i s t e d . B y e r l y et a l . , (1938) s t u d i e d g e n e t i c e f f e c t s i n f o u r c l a s s e s of embryos (mating between two s t r a i n s w i t h r e c i p r o c a l crosses) and concluded that they d i d not d i f f e r s i g n i f i c a n t l y i n s i z e from one another d u r i n g the f i r s t week of i n c u b a t i o n . During the 11 to 17 day p e r i o d , the g e n e t i c a l l y l a r g e r embryos were g e n e r a l l y s l i g h t l y - 6 -h e a v i e r than the g e n e t i c a l l y s m a l l e r embryos, even i n eggs of s i m i l a r weight. A comparison of embryo weights, c e l l counts and c e l l s i z e of two l i n e s of Barred Plymouth Rocks was conducted by Wiley (1950a). He d i d not f i n d c o n s i s t e n t d i f f e r e n c e s i n embryo weights between the two l i n e s , but demonstrated t h a t egg s i z e was p o s i t i v e l y r e l a t e d to c e l l number per u n i t area of embryo t i s s u e and n e g a t i v e l y r e l a t e d to the c e l l s i z e . McNary elt a l . (1960) measured the r a t e of embryonic growth by the number of somites present a f t e r 38 hours of i n c u b a t i o n , embryo weight a f t e r 1 and 2 weeks of i n c u b a t i o n of four i n b r e d l i n e s , t h e i r crosses and r e c i p r o -c a l s . Growth d i f f e r e n c e s i n the embryos were observed at a l l three stages. H e t e r o s i s f o r embryo growth was apparent at a l l s t a g e s , but the e f f e c t was p a r t i a l l y obscured by a maternal e f f e c t t r a n s m i t t e d by one l i n e , which p r o -duced a l a r g e r d i f f e r e n c e among r e c i p r o c a l c r o s s e s . They a l s o showed that embryos from the heavy l i n e s were c o n s i s t e n t l y l a r g e r than those from the l i g h t l i n e s . Bray and I t o n (1962) a l s o observed genetic d i f f e r e n c e s i n embryo weights from the tenth to n i n e t e e n t h day of i n c u b a t i o n . Coleman et a l . (1964) s t u d i e d embryonic development of two l i n e s o f White Plymouth Rocks. They observed embryo weights of a l i n e s e l e c t e d f o r h i g h body weight were h e a v i e r than those of a l i n e s e l e c t e d f o r low body weight at 14 to 19 days of i n c u b a t i o n . They a l s o found s i g n i f i c a n t c o r r e l a t i o n s between egg weight and embryo weight: r (high body weight at 17 days of in c u b a t i o n ) = 0.47; r (low body weight at 15, 17 and 19 days of i n c u b a t i o n ) - 7 -= 0.34, 0.40 and 0.60, r e s p e c t i v e l y . Murray (1925) p l o t t e d the Log, of embryo weight a g a i n s t Log, of time and observed an apparently s t r a i g h t l i n e . He c a l c u l a t e d the l e a s t squares l i n e of best f i t to the data and reported t h a t the average weight of chicken embryos between 5 and 19 days of i n c u b a t i o n , as found by over 3 6 600 embryo weighings, may be expressed by the equ a t i o n , W = Kt , where K = 0.668, W expresses embryo weight and t _ r e f e r s to time i n days from s t a r t of i n c u b a t i o n and 3.6 = the growth r a t e of the i n d i v i d u a l . Lerner (1939) examined the d e v i a t i o n s from l i n e a r i t y present i n the data of Murray and ot h e r s and re p o r t e d that w h i l e i n d i v i d u a l s e t s of data may produce s a t i s f a c t o r y f i t to a l o g by l o g s t r a i g h t l i n e , s mall d e v i a t i o n s i n the same d i r e c t i o n and appearing at the same time i n the m a j o r i t y of s e t s of r e l i a b l e data cannot be d i s r e g a r d e d . Lerner and Asmundson (1938) demon-s t r a t e d the d i f f e r e n c e s i n the growth r a t e of Murray's f u n c t i o n between breeds and s t r a i n s and between sexes. The decreased e a r l y growth r a t e e x h i b i t e d by l a t e r hatches w i t h i n breeds was found to l e a d to compensatory growth i n l a t e r s t a g e s . D i f f e r e n c e s i n e a r l y growth r a t e s between breeds r e f l e c t e d the d i f f e r e n c e s i n a d u l t weight. D e f i n i t i v e weights w i t h i n breeds were found to be independent of the d i f f e r e n t i a l p a t t e r n s of growth i n the e a r l y s t a g e s . Roberts (1964) proposed the power f u n c t i o n Y = at*5 to c a l c u l a t e weekly i n d i v i d u a l growth r a t e s d i r e c t l y from the data d u r i n g the p e r i o d from hatch to 10 weeks of age. In t h i s f o r m u l a , age was expressed as time from conception; Y_ i s the c h i c k body weight at time _ t , a_ i s . the body - 8 -weight at time 0, and b^  r epresents the growth r a t e . H i s r e s u l t s showed tha t the weekly growth r a t e s r e f l e c t e d a degree of l i n e a r i t y up to 7 or 8 weeks of age, and tha t when these weekly v a l u e s to 7 weeks of age were averaged, the 7-week growth r a t e provided a u s e f u l estimate f o r comparison of g e n e t i c worth of i n d i v i d u a l s or s t r a i n s . J u l l and Quinn (1925) i n v e s -t i g a t e d the r e l a t i o n s h i p between the weight of eggs and the weight of c h i c k s according to sex and concluded that there was no s i g n i f i c a n t d i f f e r -ence i n the weight of male c h i c k s and the weight of female c h i c k s from eggs l a i d by p u l l e t s . They mentioned t h a t i f p u l l e t eggs have a s i g n i f i c a n t l y lower mean weight than yearling-hetf eggs, the c h i c k s hatched from p u l l e t eggs w i l l a l s o tend to have a s i g n i f i c a n t l y lower mean weight than the c h i c k s hatched from y e a r l i n g - h e n eggs. Monro and K o s i n (1940) observed the c l o s e ( r = 0.86) and p o s i t i v e c o r r e l a t i o n between c h i c k weight and egg weight. They noted t h a t w h i l e the sex of the chick was not governed by the weight of the f r e s h egg, there was a sex d i f f e r e n c e i n the weight of day-old male and female s i b s . The d i f f e r e n c e was i n favour of males, ranging from 0.6 to 0.8 percent when body weight was expressed as a pe r c e n -tage of egg weight. Evidence of breed and sex d i f f e r e n c e s i n the weight of c h i c k s hatched from eggs of s i m i l a r weights was st u d i e d by Godfrey and Jaap (1952). They found t h a t the d i f f e r e n c e s i n body weight were u s u a l l y not present at hatc h i n g due to the e f f e c t s of egg s i z e . From the s t a t i s t i c a l s t u d i e s of v a r i a t i o n of body weight during the growth p e r i o d of s i n g l e Comb White Leghorns, Funk et a l . , (1930) concluded - 9 -that chicks were h i g h l y v a r i a b l e i n d i v i d u a l s . They found that the i n i t i a l c h i c k weights and subsequent weights were not c o r r e l a t e d , but c h i c k weights at 4, 8, 16 and 24 weeks of age show a h i g h p o s i t i v e c o r r e l a t i o n w i t h each o t h e r . Jaap and M o r r i s (1937) pointed out that growth to 8 weeks of age appears to be a separate e n t i t y and not n e c e s s a r i l y r e l a t e d to a d u l t weight. In the data of Hammond and B i r d (1942) there was a b a s i c p a t t e r n i n the body weight v a r i a t i o n of c h i c k s . Under i d e a l c o n d i t i o n s the c o e f f i c i e n t of v a r i a t i o n of body weight increased r a p i d l y from h a t c h i n g to 4 weeks o f age a f t e r which i t decreased a t the same r a t e to 10 weeks of age, then de-creased more s l o w l y u n i t i l i t reached a low constant value at m a t u r i t y . When ch i c k s were deprived of an optimum d i e t , maximum v a r i a b i l i t y d i d not occur u n t i l the s i x t h or seventh week of age. Deland (1965) found a h i g h l y s i g n i f i c a n t c o r r e l a t i o n between 6-week growth r a t e and 6-week body weight ( r = 0.86). He concluded that i n g e n e r a l , 6-week body weight of i n d i v i d u a l s bore a h i g h l y s i g n i f i c a n t r e l a t i o n s h i p w i t h a l l weekly growth r a t e s , and the peak of s i g n i f i c a n c e occurred during the second week's growth r a t e . He a l s o showed th a t 92 p e r -cent of the v a r i a t i o n i n 6-week body weight could be a s s o c i a t e d w i t h the combined v a r i a t i o n of 8-12 day embryo growth r a t e , h a t c h i n g weight and 6-week growth r a t e . 2 Schmidt (1919) f i r s t used the d i a l l e l mating (n. mating from i i males w i t h i i females) to i n v e s t i g a t e the i n h e r i t a n c e of vertebrae number i n the t r o u t , and he a l s o (1922) used t h i s system of mating i n the domestic - 10 -f o w l . Schmidt suggested that d i a l l e l matings might be used to evaluate the gene t i c m e r i t of an i n d i v i d u a l w i t h respect t o c e r t a i n q u a n t i t a t i v e t r a i t s . Sprague and Tatum (1942) used a mo d i f i e d d i a l l e l mating to study n o n - a d d i t i v e gene e f f e c t s i n the y i e l d of 45 s i n g l e crosses of 10 inbred l i n e s of c o r n . I n t h i s study i t was found that general combining a b i l i t y ( a d d i t i v e genetic e f f e c t ) was more important than s p e c i f i c combining a b i l i t y ( n on-additive g e n e t i c e f f e c t ) among untested l i n e s , but the s i t u a t i o n was reversed among t e s t e d l i n e s . Using d i a l l e l matings, Lerner (1945) and Hazel and Lamoreux (1947) s t u d i e d the importance of non - a d d i t i v e gene e f f e c t s i n the sexu a l m a t u r i t y of f l o c k s of S i n g l e Comb White Leghorns s e l e c t e d f o r high egg p r o d u c t i o n . Lerner s e l e c t e d matings i n which 2 dams had been mated at d i f f e r e n t times to each of 2 d i f f e r e n t s i r e s . The s i z e of the f u l l - s i b f a m i l i e s ranged from 3 to 6 p u l l e t s . The experiment of Hazel and Lamoreux i n v o l v e d 3 s e r i e s of males; each s e r i e s had 60 s i n g l e male pens w i t h 6 females per pen. The average f u l l - s i b f a m i l y s i z e was 6.31. Both i n v e s t i g a t i o n s i n d i c a t e d t h a t the non - a d d i t i v e gene e f f e c t s c o n t r i b u t e d only one percent i n the v a r i a t i o n of sexual m a t u r i t y . Hazel and Lamoreux found t h a t maternal e f f e c t s were estimated to account f o r about 5 percent of the v a r i a t i o n i n body weight, but no i n f l u e n c e on sexual m a t u r i t y could be demonstrated. Kan, et a l . (1959) used a t o t a l of 119 d i a l l e l analyses to i n v e s t i -gate the importance of non - a d d i t i v e gene e f f e c t s i n 6 b r o i l e r t r a i t s i n -c l u d i n g 4-week weight and 9-week weight. He found t h a t the no n - a d d i t i v e - 11 -gene e f f e c t s were of co n s i d e r a b l e importance i n c o n t r i b u t i n g to the v a r i a -t i o n i n shank l e n g t h , k e e l l e n g t h and body depth, but were of questionable importance as a c o n t r i b u t o r to the v a r i a t i o n i n g a i n i n weight from 4 to 9 weeks and appeared to have l i t t l e or no e f f e c t on body weight at e i t h e r 4 or 9 weeks of age. The d i a l l e l cross method of i n v e s t i g a t i n g the g e n e t i c a l p r o p e r t i e s of a group of homozygous l i n e s has r e c e i v e d much a t t e n t i o n . H u l l (1945) has considered some aspects of the method. A short summary of a more general approach by J i n k s and Hayman (1953) and i t s a p p l i c a t i o n to s e v e r a l p u b l i s h e d s e t s of maize data has a l s o appeared. J i n k s (1954) has d e s c r i b e d experiments on i n b r e d l i n e s of Nicotiana vustica3 and has given an account of some of the a s s o c i a t e d s t a t i s t i c s together w i t h a d i s c u s s i o n of the r e s u l t s . Hayman (1954) mentioned t h a t , experiments w i t h d i a l l e l crosses provided a powerful method of i n v e s t i g a t i n g p o l y g e n i c systems. H i s paper showed that the v a r i o u s s t a t i s t i c s obtained from measurements on the progeny provided estimates of the o v e r a l l degree of dominance, p r o p e r t i e s of the p a r e n t s , and of the sym-metry or otherwise of the gene d i s t r i b u t i o n i n the l i n e s . G r i f f i n g (1956) p o i n t e d out that when i n t e r p r e t e d i n terms of the c l a s s i c a l method of covariances between r e l a t i v e s , the method of d i a l l e l c r o s s e s , y i e l d s estimates e q u i v a l e n t to those obtained by covariance between parents and o f f s p r i n g . Kempthome (1956) s t a t e d that the d i a l l e l c r o s s must be i n t e r p r e t e d i n terms of some p o p u l a t i o n which has gi v e n r i s e to the homozygous parents by i n b r e e d i n g . - 12 -I f such a p o p u l a t i o n does not e x i s t then the whole a n a l y s i s can be ques-t i o n e d . Goto and Nordskog (1959) estimated combining a b i l i t y from d i a l l e l crosses of 21 inbred l i n e s , 12 of these were white egg Leghorn t y p e s , w h i l e 9 were brown egg heavy breed t y p e s . They estimated v a r i a n c e s of general combining a b i l i t y , s p e c i f i c combining a b i l i t y , maternal e f f e c t s and r e c i p r o c a l e f f e c t s . T h e i r r e s u l t s i n d i c a t e d that general combining a b i l i t y was more important than s p e c i f i c combining a b i l i t y f o r almost a l l c h a r a c t e r s s t u d i e d . Waters and Bywaters (1943) i n d i c a t e d White Leghorns showed i n t e r -s t r a i n d i f f e r e n c e s i n average weight, not only during the growth p e r i o d (1-3 months of age) but a l s o at the time a d u l t weight (10 months) was a t -t a i n e d . T h e r e f o r e , d i f f e r e n c e s i n the inherent r a t e of a d u l t weight may have e x i s t e d i n these s t r a i n s but t h i s hypothesis could not be confirmed i n t h e i r study. 2 Godfrey and W i l l i a m s (1952) obtained h e r i t a b i l i t y estimates (h ) f o r a l i n e of S i l v e r Oklabars which were s e l e c t e d f o r r a p i d growth, and on another l i n e which was s e l e c t e d f o r slow growth. They obtained a f t e r 2 2 generations of s e l e c t i o n , h estimates of 0.19 and 0.30 f o r body weight at 6 weeks of age, and estimates of 0.31 and 0.32 f o r body weight at 12 weeks 2 of age f o r the f a s t and slow l i n e , r e s p e c t i v e l y . Estimates of h c a l c u l a t e d f o r males were c o n s i s t e n t l y lower at both ages than those c a l c u l a t e d f o r 2 females. Goodman and Godfrey (1956) estimated h of body weight at 9 weeks of age. T h e i r estimate averaged 0.43. They concluded t h a t the n o n - a d d i t i v e g e n e t i c v a r i a n c e , as measured by the s i r e x dam i n t e r a c t i o n component, was - 13 -e i t h e r s m a l l or non-existent f o r t h i s t r a i t . Jerome et a l . (1956) d i s -2 cussed that the most r e l i a b l e h estimates were obtained by the use of a combination of the s i r e and dam v a r i a n c e components. T h i s method c o r r e c t e d somewhat f o r the v a r i a b i l i t y of estimates obtained from o n l y 1 component and i n a d d i t i o n brought the c o n t r i b u t i o n of any s e x - l i n k e d or maternal e f -f e c t s i n l i n e w i t h the e f f e c t s they would exert i n a c t u a l breeding p l a n s . I n an experiment extending over 7 t r i a l s conducted by Thomas et a l . (1958), h e r i t a b i l i t i e s f o r body weight at d i f f e r e n t ages were estimated f o r b r o i l e r s . The data i n v o l v e d 1,196 progenies from 56 s i r e s and 218 dams. They were analyzed on the b a s i s of the mean performance of the o f f s p r i n g of 2 the same sex from the v a r i o u s matings. The estimates of h of weight at v a r i o u s ages were g e n e r a l l y higher than those p r e v i o u s l y reported f o r t h i s 2 c h a r a c t e r . A divergence i n the estimates of h from male and female progeny f o r the same ch a r a c t e r presented some evidence that s e x - l i n k e d genes are of 2 c o n s i d e r a b l e importance. S i e g e l (1962) summarized the p u b l i s h e d h estimates 2 of body weights f o r ages ranging from 6 to 12 weeks. The h estimates ranged from -0.20 to 1, however the higher frequencies ranged from 0.20 to 0.60. These estimates were based on s e v e r a l methods and the parameters were 2 obtained using many d i f f e r e n t p o p u l a t i o n s . However, the mode of h estimates f o r 8 week body weight was very c l o s e to 0.40. This i n d i c a t e d t h a t , i n 2 g e n e r a l , h of 8-week body weight i s r e l a t i v e l y high i n most p o u l t r y 2 p o p u l a t i o n s . Moyer et a l . (1962) estimated the h of body weight at 4, 6 and 8 weeks of age on approximately 4,900 F cross-bred progeny - 14 -from 96 s i r e s and 653 dams. H e r i t a b i l i t y estimated from the s i r e v a r i a n c e components appeared i n general to i n c r e a s e s l i g h t l y between 4 and 8 weeks 2 of age. The s i r e component h estimates f o r males at 4 and 8 weeks of age were 0.20 and 0.24, and f o r females 0.26 and 0.35, r e s p e c t i v e l y . H e r i t a b i l i t y estimates from the dam v a r i a n c e component compared to those from the s i r e were l a r g e r and g e n e r a l l y decreased between 4 and 8 weeks: 2 h estimates from the dam component of var i a n c e f o r males at 4 and 8 weeks of age were 0.81 and 0.68 and f o r females 0.99 and 0.94, r e s p e c t i v e l y . MATERIALS AND METHODS Four l i n e s of chickens were used i n t h i s study: Black A u s t r a l o r p (BA), S i n g l e Comb White Leghorn (LH), New Hampshire (NH) and the U n i v e r s i t y of B r i t i s h Columbia S i n g l e Comb White Leghorns (UBC). The BA l i n e has been a c l o s e d and random breeding p o p u l a t i o n s i n c e 1964. The base s i z e o f the p o p u l a t i o n has not been l e s s than 240 females and 80 males. I t i s c h a r a c t e r i s e d by medium body weight w i t h f a i r l y good egg p r o d u c t i o n . The MH l i n e has been a closed and random breeding p o p u l a t i o n f o r a t l e a s t 15 years a t The U n i v e r s i t y of B r i t i s h Columbia. I t i s a t y p i c a l egg pr o d u c t i o n stock, l i g h t body weight, a h i g h degree of l i v a b i l i t y and l a r g e egg s i z e . The NH l i n e has been maintained at The U n i v e r s i t y of B r i t i s h Columbia as a random mating p o p u l a t i o n f o r at l e a s t 18 y e a r s . I t combines medium body weight w i t h f a i r l y good egg p r o d u c t i o n . The UBC l i n e has been a cl o s e d breeding p o p u l a t i o n s i n c e 1958 and random bred s i n c e 1959. I t i s c h a r a c t e r i z e d by good egg p r o d u c t i o n , a good l i v a b i l i t y , l a r g e egg s i z e , and f a i r l y l i g h t body weight. A t o t a l of 100 hens and 16 males represented each l i n e . Hens of each l i n e were randomized i n t o 4 groups of 25 hens. A l l hens were housed i n i n d i v i d u a l cages. The 16 males of each l i n e were randomly d i v i d e d i n t o 4 groups. Each male group was randomly assigned to a female group. The male groups were r o t a t e d throughout the females f o r each a r t i f i c i a l i n s e m i -n a t i o n p e r i o d . The semen was c o l l e c t e d i n d i v i d u a l l y from each male and - 16 -then inseminated to 6 to 7 hens. A twice«sweekly r o t a t i o n of the males and the i n d i v i d u a l c o l l e c t i n g o f semen was done i n order to minimize i n d i v i d u a l male e f f e c t s . T h i s r e s u l t e d i n a 4 x 4 l i n e d i a l l e l mating. A r t i f i c i a l i n s e m i n a t i o n was performed twice a week f o r 4 weeks. Eggs were gathered d a i l y i d e n t i f i e d as to o r i g i n , dated and then i n d i v i d u a l l y weighed and r e -corded to the nearest gram before being placed d i r e c t l y i n t o a c o o l i n g room maintained a t approximately 55°? and 60 percent r e l a t i v e h u m i d i t y . A l l eggs were turned d a i l y . Two r e p l i c a t i o n s each c o n s i s t i n g 3 weeks saving of eggs were t e s t e d . A f t e r 3 weeks of c o l l e c t i o n , a l l eggs were re-weighed and trayed f o r i n c u b a t i o n . Each egg was i d e n t i f i e d as to g e n e t i c o r i g i n and i t s weight a f t e r s t o r a g e , was obtained f o r each of 4,000 eggs of each r e p l i c a t i o n . Before t r a y i n g , the eggs of each mating were randomly d i v i d e d i n t o 2 groups; those that were assigned f o r hatching and those that were assigned f o r em-bryo weighing during i n c u b a t i o n . The eggs that were assigned f o r the embry-onic t e s t were f u r t h e r randomly subdivided i n t o 7 s u b s e t s , w i t h the r e s t r i c -t i o n that approximately 7 eggs of each week of l a y were present i n each mating subset. One of the 7 subsets would be broken out and the embryos weighed on each of the a l t e r n a t e days from 6 to 18 days o f i n c u b a t i o n , i n -c l u s i v e . The corresponding subsets of each mating were then brought together and randomly d i s t r i b u t e d i n t o incubator t r a y s . The t r a y s were then randomly d i s t r i b u t e d i n t o two Jamesway Model 252 i n c u b a t o r s . In order to minimize growth o c c u r i n g between the withdrawal of the t r a y s and the a c t u a l weighing of the embryos the assigned t r a y s were withdrawn at 48 hour i n t e r v a l s and - 17 -refrigerated overnight. Before weighing, each embryo was separated from i t s extras-embryonic membranes by cutting the umbilical cord at i t s juncture with the abdomen. The embryo was then placed on a piece of absorbent paper for a few seconds i n order to drain off excess moisture before weighing. I n f e r t i l e eggs and embryos which had died p r i o r to removal from the incubator, as w e l l as ob-viousl y deformed embryos were discarded. Embryo weights were taken to the nearest thousandth of a gram. The sex of the embryo was determined for a l l embryos s t a r t i n g on the eighth day of incubation. Approximately 2,500 eggs were broken out over the 7 weighing periods of each r e p l i c a t i o n , or approxi-mately 5,000 eggs for the embryo experiment. Those eggs that were assigned for hatching were trayed at random throughout the incubators. These eggs were candled at 18 days of incubation and v i a b l e eggs were transferred into i n d i v i d u a l hatching trays. Each trans-ferred egg was placed under an inverted polythene basket with the i n d i v i d u a l wire frame covers. In t h i s fashion, i n d i v i d u a l hatching data could be obtained. The hatched chicks were i n d i v i d u a l l y i d e n t i f i e d and weighed to the nearest gram, and were given an i n j e c t i o n of Mareck vaccine. The chicks were distr i b u t e d into 4 f l o o r brooding pens. A commercial b r o i l e r r a t i o n was fed ad l i b i t u m . Standard f l o o r brooding techniques were followed. A n t i b i o t i c was added to the drinking water for the f i r s t 3 days i n recommended amounts. Mortality was recorded d a i l y . Individual body weights i n grams were recorded weekly to 7 weeks of age. - 18 -The sex was determined by v i s u a l i n s p e c t i o n o r postmortem, and was recorded at 7 weeks of age at which time the t r i a l was terminated. As o n l y 1 body weight o b s e r v a t i o n could be made f o r any embryo, i t was impossible to c a l c u l a t e the i n d i v i d u a l embryonic growth r a t e s . I t was assumed that the growth r a t e s between 2 embryonic weighing pe r i o d s could be estimated f o r any mating genotype by u s i n g the average of the embryonic weights of those i n d i v i d u a l s w i t h i n a mating genotype and sex. Embryonic growth r a t e estimates were c a l c u l a t e d f o r each of the 2 -day pe r i o d s be-tween 6 and 18 days of i n c u b a t i o n , and the 2 ^ a y estimates were averaged i n d i f f e r e n t combination to provi d e values f o r the f o l l o w i n g embryo growth p e r i o d s : 8-12, 8-14, 8-16, 8-18, 10-14, 10-16, 10-18, 12-16, 12-18, and 14-18 day embryo growth r a t e . The body weights of i n d i v i d u a l progeny during the growth phase be-tween hatch and 7 weeks of age (as w e l l as that of the averaged embryo body weight) were assumed to f o l l o w the power f u n c t i o n (Roberts, 1964), Y = a t ^ , where Y_ i s equal to the body weight of the i n d i v i d u a l at time _t , a_ i s equal to the body weight of the i n d i v i d u a l at time zero or at c o n c e p t i o n , and b_ repre s e n t s the growth r a t e of the i n d i v i d u a l . Weekly growth r a t e estimates were c a l c u l a t e d between hatching and 7 weeks of age f o r each progeny. The averaged weekly values provided a s i n g l e estimate of growth r a t e from hatch to 7 weeks of age (H-7 week growth r a t e ) . STATISTICAL METHODS The general model assumed to e x p l a i n the sources of v a r i a t i o n i n the embryonic body weights was: Y. .. = y + s. + d. + (sd) . . + f. + ( s f ) + (df) .. + (sdf) . .. + l j k l i J i J k i k j k x j k rl + ( s r )i l + ( d r )j l + ( f r )k l + ( s d r )i j l + ( s f r )i k l + (df r) , + e. ., ... ' j k l i j k l where, ^ ' - j j ^ i represents the averaged va l u e of each mating genotype w i t h i n each sex and r e p l i c a t i o n , u = the p o p u l a t i o n parameter, s^ = the e f f e c t of the i * *1 s i r e l i n e ( i = 1-4) , th dj = the e f f e c t of the j dam l i n e ( j = 1-4), f k = the e f f e c t of the kt h sex (k = 1-2), rl the e f f e c t of the 1 ^ r e p l i c a t i o n (1 = 1-2) , and e. ., n = the u n c o n t r o l l e d , random environmental and g e n e t i c d e v i a t i o n l j k l a t t r i b u t a b l e to the mating c e l l mean. A l l e f f e c t s were considered to be random except f o r the r e p l i c a t i o n e f f e c t ( r ^ ) which was considered to be f i x e d . The general model assumed to describe each of the growth periods was: - 19 -- 20 -b . . . = y + s . + d. + ( s d ) . . + f t + ( s f ) . , + ( d f ) . . + ( s d f ) . . , + i j k l M 1 j i j k ' i k ' j k ' l j k ^ + isr)±1 + ( d r ) j ; L + ( s d r ) i j ; L + ( f r ) f c l + ( s f r ) i k l + ( d f r ) j k l + e l j k l , which d i f f e r e d from the model assumed to d e s c r i b e the body weight o n l y i n the phenotype analyzed (growth r a t e v s . body w e i g h t ) . I n the analyses of v a r i a n c e of the post-hatch d a t a , the average val u e w i t h i n each mating genotype of each sex and r e p l i c a t i o n was used as the sample o b s e r v a t i o n . The s t a t i s t i c a l model assumed to e x p l a i n the sources of v a r i a t i o n of the average body weight observations, at ha t c h i n g and at weekly i n t e r v a l s to 7 weeks o f age and each of the growth pe r i o d s were analogous to those used f o r the embryonic d a t a . The expected mean squares d e r i v e d from the models are shown i n Table 1. The simple c o r r e l a t i o n s (r) and the c o e f f i c i e n t s of de t e r m i n a t i o n 2 based on simple l i n e a r c o r r e l a t i o n ( r ) and m u l t i p l e l i n e a r r e g r e s s i o n 2 models (R ) were c a l c u l a t e d from i n d i v i d u a l c h i c k data as w e l l as from averaged data w i t h i n the d i a l l e l mating c e l l and r e p l i c a t i o n . The d i a l l e l c r o s s i n g system used i n t h i s experiment was, according to G r i f f i n g ' s 1956 c l a s s i f i c a t i o n , method 1; i n b r e d s , 1 set of F ^ ' s , and the r e c i p r o c a l F^'s were i n c l u d e d . Each set con s i s t e d of a l l p o s s i b l e matings of 4 in b r e d l i n e s , a n d was regarded as a set of "4 x 4" matings. Assuming that the experimental m a t e r i a l c o n s t i t u t e s a random sample from a random mating p o p u l a t i o n , the a d d i t i v e and n o n - a d d i t i v e g e n e t i c TABLE 1. EXPECTED MEAN SQUARES FOR THE ANALYSES OF BODY WEIGHTS AND GROWTH RATES OF PRE- AND POST-HATCH CHICK DATA Source of v a r i a t i o n d.f. Expected mean squares S i r e l i n e (S) 3 a 2 e + 2 aSDF + 1 6 aS F + 4°SD + 1 6° S Dam l i n e (D) 3 o2 e + 2°SDF + 8°DF + 4 aSD + 1 6° D S x D 9 a 2 e + 2o2 SDF + 4a2 SD Sex (F) 1 c 2 e + 2o2 SDF + 8 aDF + 1 6° S F + 3 2° F S x F 3 o2 e + 2 o2 SDF + 2 1 6°S F D x F 3 o2 e + SDF + 8a2 DF S x D x F 9 o2 e + 2°SDF R e p l i c a t i o n (R) 1 o2 e + 4a2 DRF 8a2 DR + + 2 2 2 4°SFR + 1 6°F R + 2°SDR + 1 6°SR + 3 2 6R S x R 3 o 2 e + 4 a2 SFR + 2 2 2o + 16o SDR SR D x R 3 a 2 e + 4 a2 DFR + 2 2 2a + 8a SDR DR S x D x R 9 a2 e + 2 a2 SDR F x R 1 a2 e + . 2 DFR + 2 2 4o + 16a SFR FR S x F x R 3 a2 e + , 2 4a SFR D x F x R 3 a2 e + 4o2 DFR R e s i d u a l 9 a2 e T o t a l 63 - 22 -v a r i a n c e s of the parent p o p u l a t i o n can be estimated. This experiment assumed that i t was d e a l i n g w i t h random samples from some parent p o p u l a t i o n , and i n f e r e n c e s are not to be made about the i n d i v i d u a l l i n e s i n the t e s t but about the parameters of the parent p o p u l a t i o n . I n p a r t i c u l a r , we were i n t e r e s t e d i n e s t i m a t i n g the g e n e t i c and environmental components of the complex p o p u l a t i o n v a r i a n c e . Because of d i s p r o p o r t i o n a t e subclass numbers i n a l l t r a i t s s t u d i e d the procedure of l e a s t - s q u a r e s a n a l y s i s d e s c r i b e d by Harvey (1968) was employed f o r the h e r i t a b i l i t y e s t i m a t e s . The model assumed to d e s c r i b e the v a r i a b i l i t y of each i n d i v i d u a l w i t h i n each sex and r e p l i c a t i o n was: Y. ., = u + s, + d. + ( s d ) . . + e. 13k i j ±3 Where, p. = the p o p u l a t i o n parameter, s^ = the e f f e c t of the i * " *1 s i r e l i n e ( i = l*-4) , dj = the e f f e c t of the j * " *1 dam l i n e ( j = 1-4), and e..^ = the u n c o n t r o l l e d , random environmental and g e n e t i c d e v i a t i o n X^ a t t r i b u t a b l e to the i n d i v i d u a l (k = 1-n..,). i j k A l l e f f e c t s were considered to be random. C a l c u l a t i o n s of the analyses o f v a r i a n c e , r e g r e s s i o n s and c o r r e l a -t i o n s were done on The U n i v e r s i t y of B r i t i s h Columbia I.B.M.360/74 computer. Duncan's new m u l t i p l e range t e s t , as c i t e d by S t e e l e and T o r r i e (1960), was used to t e s t d i f f e r e n c e s between means w i t h i n the main e f f e c t s of the ana-l y s e s of v a r i a n c e . A l l the hypotheses t e s t i n g the c o r r e l a t i o n and r e g r e s s i o n analyses was H: p = 0. The term " s i g n i f i c a n t " was used to r e f e r to d i f f e r e n c e s among sample means which, on the b a s i s of s t a t i s t i c a l a n a l y s i s , were expected t o r e f l e c t - 23 -t r u e d i f f e r e n c e s among the population-means w i t h a p r o b a b i l i t y of not more than 0.05 ( P ^ O . 0 5 ) . E s t i m a t i o n of Variance Components and H e r i t a b i l i t y The a n a l y s i s of v a r i a n c e used to c a l c u l a t e the v a r i a n c e components i s g i v e n i n Table 2. The lc, c o e f f i c i e n t s of v a r i a n c e components, were c a l -2 c u l a t e d a f t e r Harvey (1960). The h e r i t a b i l i t y (h ) was estimated w i t h i n each sex and r e p l i c a t i o n from the s i r e component by: 4 o2 h 2 = A S s o ^ + o ^ + o ^ + C J 2 S D (SD) ^ e and from the dam component by h 2 . 4 £ d -2 + 2 + 2 + j. °S ' "D ' "(SD) The standard e r r o r of the h e r i t a b i l i t y estimates (S.E.) were c a l -c u l a t e d u s i n g the formula a f t e r Swiger et a l . (1964); o /2(N-1) ( 1 - t )2 l + ( k - l ) t 2 S.E. ( h p = 4 Y k (N-s) (s-1) Where N = number of i n d i v i d u a l s , 2 t = i n t r a c l a s s c o r r e l a t i o n (1/4 h ) , k = c o e f f i c i e n t of v a r i a n c e component, and s = number of s i r e l i n e s . 2 The standard e r r o r of h e r i t a b i l i t y estimates f o r the dam component (h^) was c a l c u l a t e d i n an analogous f a s h i o n . - 24 -TABLE 2. ANALYSIS OF VARIANCE FOR THE CALCULATION OF HERITABILITY ESTIMATES ON THE PRE- AND POST-HATCH DATA Source of Expected variation d.f. mean squares Sire line (S) Dam line (D) S x D In. - 1 . l l En. - 1 3 J (En.. - 1)( En. i 1 3 3 1) e 4 sd 5 s 2 . , 2 . , 2 °e + Vsd + Vd 2 , , 2 a + k-.a e 1 sd Residual n... —En.En. i X3 2 Total n...-1 k„ = k„ = k, = k. = En.En. - En. - En. + 1 1 J i j J (n..,-E En 2. .1 1 J - E E i 2 n. . i j + E 2 n. . E 1 J ) i n. X 3 n. 3 i j n.. 2 2 En.. E En .. En. - 1 i n. 3 2 2 En 2. E n T ^ l ( n'- - ^ ~ ) 3 2 n. n. . _1_ i En 2. 4 1 I En. - 1 x n. . 1 i x - E E J-3 . n. En. 1 , . l , — — 1 ( n . . - x _ ) . x x n. n. = no. of sire lines; 1 i - 1 - 4 n. = no. of dam lines; 3 j = 1 - 4 n. ., = no. of individuals in each d i a l l e l mating c e l l ; k = 1 - no. of individual in each d i a l l e l c e l l . RESULTS AND DISCUSSION Embryo Weights The number of embryos s t u d i e d i n t h i s experiment f o r each r e p l i c a -t i o n sex and genotypic mating i s presented i n Appendix Table 1. A t o t a l of 4471 embryos were weighed 2,178 and 2,293 embryos i n the f i r s t and second r e p l i c a t i o n , r e s p e c t i v e l y . The sex r a t i o s i n bo t h r e p l i c a t i o n s were c l o s e to 50:50 as expected. The number of embryos at the same stage of i n c u b a t i o n averaged i n each sex, genotypic mating and r e p l i c a t i o n was about 8, except f o r those of embryos at 6 days of i n c u b a t i o n which were not sexed, and averaged f o r each genotypic mating and r e p l i c a t i o n about 14. Table 3 shows the mean embryo weights recorded at 2 day i n t e r v a l s from 6 to 18 days of i n c u b a t i o n . In g e n e r a l , there was f a i r l y good agreement between the s i r e and dam l i n e averaged 6^day embryo weights f o r each l i n e . However, the BA dam l i n e mean was 0.41 grams i n cont r a s t w i t h 0.36 grams f o r the s i r e l i n e mean. At 18 days of i n c u b a t i o n the s i r e and dam l i n e means of the BA agreed f o r the male and female progeny. The NH, MH and UBC s i r e and dam l i n e means were i n good agreement f o r both sexes of the progeny a t 18 days of age. Among the i n b r e d l i n e s , the NH l i n e had the highest mean body weight a t 18 days of age w i t h the values of 27 and 26 grams f o r male and female progeny, r e s p e c t i v e l y . The l i g h t e s t i n b r e d l i n e was the MH w i t h the mean values of 24 and 23 grams f o r the male and female progeny. - 25 -- 26 -TABLE 3. MEAN EMBRYO WEIGHTS (GM.) AT TWO DAY INTERVALS (D) ACROSS REPLICATIONS FROM 6 TO 18 DAYS OF INCUBATION FOR MALE (M) AND FEMALE (F) PROGENY S i r e l i n e BA MH NH UBC Mean Dam l i n e D M F M F M F M F M F BA MH NH 6 0 .38 0 .40 0 .43 0 .43 0 .41 8 1.34 1.32 1.39 1. 26 1.33 1.29 1.35 1.29 1.35 1.29 10 2.72 2.58 2.86 2. 88 2.84 2.75 2.87 2.74 2.82 2.74 12 5.89 5.56 6.15 5. 79 6.55 6.13 5.79 5.72 6.09 5.80 14 11.08 10.88 11.98 11. 46 11.76 11.10 11.80 11.18 11.65 11.16 16 18.00 17.72 18.54 17. 74 18.99 17.60 18.60 17.84 18.54 17.23 18 25.36 24.15 26.42 25. 26 27.10 25.90 26.62 26.12 26.37 25.36 6 0 .32 0 .32 0 .34 0 .32 0 .33 8 1.20 1.25 1.18 1. 10 1.22 1.08 1.21 1.22 1.20 1.16 10 2.48 2.45 2.54 2. 49 2.61 2.58 2.56 2.48 2.54 2.50 12 5.50 5.34 5.26 5. 22 5.72 5.48 5.50 5.18 5.48 5.30 14 10.50 10.91 10. 78 9. 95 10.99 10.82 10.57 10.68 10.71 10.59 16 16.88 16.98 17.50 16. 66 17.80 16.98 17.34 17.26 17.38 16.97 18 25.18 24.40 24.03 22. 88 26.68 24.76 24.90 24.48 25.20 24.13 6 0 .36 0.36 . 0 .36 0 .38 0 .36 8 1.33 1.24 1.29 1. 18 1.26 1.18 1.33 1.27 1.30 1.22 10 2.77 2.63 2.72 2. 48 2.66 2.65 2.87 2.70 2.76 2.61 12 5.85 5.26 5.96 5. 45 5.64 5.55 5.85 5.86 5.82 5.53 14 11.32 10.82 11.28 11. 12 11.38 11.25 11.84 11.28 11.45 11.12 16 18.72 18.16 18.40 18. 26 18.16 17.94 18.78 18.33 18.52 18.17 18 26.76 25.22 26.68 26. 25 27.03 26.10 26.16 26.12 26.82 25.92 6 0 .38 0. 34 0 .34 0.36 0 .35 8 1.36 1.28 1.32 1.25 1.27 1.29 1.26 1.16 1.30 1.25 10 2.72 2.66 2.81 2.65 2.80 2.71 2.71 2.62 2.76 2.66 UBC 12 5.77 5.49 5.61 5.28 5.78 5.64 5.79 5.30 5.74 5.43 14 11.44 10.80 10.92 10.50 11.66 11.29 10.98 10.66 11.25 10.81 16 18.72 17.42 17.16 17.48 18.38 18.02 17.68 17.68 17.99 17.65 18 26.92 26.19 25.12 24.82 26.46 26.56 25.50 25.60 25.80 25.79 6 0 .36 0. 36 0 .37 0, .37 0 .36 8 1.30 1.27 1.30 1.20 1.27 1.21 1.29 1.23 1.29 1.23 10 2.67 2.58 2. 73 2.62 2.73 2.67 2.75 2.63 2.72 2.63 Mean 12 5.75 5.41 5.74 5.44 5.92 5.70 5.73 5.51 5.79 5.52 14 11.09 10.85 11.24 10.76 11.44 11.11 11.30 10.95 11.27 10.92 16 18.08 17.57 17.90 17.53 18.34 17.64 18.10 17.78 18.10 17.63 18 26.06 24.99 25.56 24.80 26.82 25.83 25.80 25.60 26.06 25.30 BA = Black A u s t r a l o p ; MH - Mount Hope; NH = New Hampshire; UBC = UBC Leghorn l i n e . - 27 -In the a n a l y s i s of va r i a n c e of the 6-day embryo weight (Table 4) of which no sex was recorded, there was a s i g n i f i c a n t dam e f f e c t and a non-s i g n i f i c a n t s i r e e f f e c t . Comparing the means i n v o l v e d (Table 3) i t was found that the s i g n i f i c a n t dam e f f e c t was b a s i c a l l y a t t r i b u t a b l e to the MH l i n e having the lowest averaged value 0.33 grams which was s i g n i f i c a n t l y d i f f e r e n t from the NH l i n e (0.36 grams) and the UBC l i n e (0.35 grams) which were not s i g n i f i c a n t l y d i f f e r e n t between themselves, but a l l 3 l i n e s were s i g n i f i c a n t l y d i f f e r e n t from the BA l i n e (0.41 grams). As a comparison, the 4 s i r e l i n e s were not s i g n i f i c a n t l y d i f f e r e n t and t h e i r average values d i d not measurably d i f f e r : MH (0.36), NH (0.37), UBC (0.37) and BA (0.36). The s i r e and dam l i n e values d e f i n i t e l y d i d not agree. The r e p l i c a t i o n e f f e c t on the 6-day embryo weights was s i g n i f i c a n t w i t h the mean valu e of 0.33 grams and 0.39 grams i n r e p l i c a t i o n 1 and r e p l i -c a t i o n 2, r e s p e c t i v e l y . The analyses of variance of body weights from 8 to 18 days of age i s presented i n Table 5. In general the second order i n t e r a c t i o n s were not s i g n i f i c a n t i n the 8 day embryos. The 3-way i n t e r a c t i o n terms were pooled i n t o the t e s t i n g term. There were 3 out of 5 f i r s t order i n t e r a c t i o n s s i g -n i f i c a n t at 8 days of i n c u b a t i o n . T h e r e a f t e r no f i r s t order i n t e r a c t i o n s were s i g n i f i c a n t . The s i r e l i n e e f f e c t was n o n - s i g n i f i c a n t f o r a l l of the embryonic ages. The dam l i n e e f f e c t was c o n s i s t e n t l y s i g n i f i c a n t s t a r t i n g at 8 days of i n c u b a t i o n . The sex e f f e c t as w e l l as the r e p l i c a t i o n e f f e c t were s i g n i f i c a n t throughout s t a r t i n g at 8 days of i n c u b a t i o n , w i t h the ex-ce p t i o n of r e p l i c a t i o n at 12 and 14 days of i n c u b a t i o n . Males were h e a v i e r - 28 -TABLE 4. SUMS OF SQUARES FROM THE ANALYSIS OF VARIANCE OF 6-DAY EMBRYO WEIGHTS, CALCULATIONS BASED ON CELL MEANS Source of v a r i a t i o n d.f. Sums of squares S i r e l i n e (S) 3 0.0013 Dam l i n e (D) 3 0.0293* S x D 9 0.0047 R e p l i c a t i o n (R) 1 0.0264* S x R 3 0.0005 D x R 3 0.0031 R e s i d u a l 9 0.0032 T o t a l 31 0.0687 S i g n i f i c a n t (P <_ 0.05). TABLE 5. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN EMBRYO WEIGHTS AT TWO DAY INTERVALS FROM 8 TO 18 DAYS OF INCUBATION, CALCULATIONS BASED ON DIALLEL CELL MEANS Days of Incubation bource or v a r i a t i o n d.f. 8 10 12 14 16 18 S i r e l i n e (s) 3 0.02 0.05 0.56 0.96 0.72 11.00 * A A A A A Dam l i n e (D) 3 0.16 0.57 2.49 5.35 12.44 23.74 S x D 9 * 0.04 0.17 . 1.06 2.72 2.73 14.97 Sex (F) A A A A A A 1 0.06 0.14 1.19 1.94 3.61 9.19 S x F 3 <0.01 <0.01 0.04 0.12 0.34 1. 75 D x F 3 <0.01 0.02 0.04 0.33 . 0.61 1.86 S x D x F 9 0.03 0.04 0.40 1.05 2.56 1.56 R e p l i c a t i o n (R) * A A A 1 0.06 0.28 0.18 0.32 11.61 50.29 S x R 3 * 0.03 0.11 0.02 0.13 1.08 1.50 D x R 3 A 0.05 0.05 0.02 2.13 1.17 1.29 S x D x R 9 A 0.04 0.11 0.11 1.83 2.06 10.31 F x R 1 ' A 0.01 <0.01 <0.01 0.02 0.11 1.72 S x F x R 3 <0.01 0.14 0.13 0.09 2.14 0.43 D x F x R 3 <0.01 0.05 0.10 0.23 0.65 6.07 Residual 9 <0.01 0.12 0.50 1.26 2.29 5.62 T o t a l 63 0.54 1.89 6.84 18.48 44.12 141.30 S i g n i f i c a n t (P <_ 0.05). - 30 -than females c o n s i s t e n t l y from 8 to 18 days o f age (Table 6 ) . T h i s was i n b a s i c agreement w i t h Deland (1967). The mean body weights i n r e p l i c a t i o n 2 were higher than those i n r e p l i c a t i o n 1 w i t h the s i n g l e e xception of the 14 day embryo weight. Because of the sex d i f f e r e n c e s , i t was deemed a d v i s a b l e to analyse a l l of the subsequent data based on s e p a r a t i o n of the two sexes. The analyses of v a r i a n c e of male embryo weights i s shown i n Table 7. S t a r t i n g a t 8 days of age through 16 days there was a s i g n i f i c a n t dam l i n e e f f e c t . There were no s i g n i f i c a n t s i r e l i n e d i f f e r e n c e s . At 8 days and 18 days of age there was a r e p l i c a t i o n e f f e c t . A l l 2-way i n t e r a c t i o n s were n o n - s i g n i f i c a n t . The s i r e and dam l i n e means of male embryo weights i s p r e -sented i n Table 8. There were no s i g n i f i c a n t d i f f e r e n c e s among the s i r e l i n e s but f o r the dam l i n e s i t showed th a t the male progeny of the MH l i n e were s i g n i f i c a n t l y d i f f e r e n t from the other 3 l i n e s at 8 and 10 days of age. At 12 days of age they had the lowest average body weight, but t h i s was non-s i g n i f i c a n t from the NH and UBC l i n e s , but s i g n i f i c a n t l y d i f f e r e n t from the BA. At 14 days of age the MH l i n e was s i g n i f i c a n t l y d i f f e r e n t from the 3 l i n e s t e s t e d . At 16 days of age i t was s i g n i f i c a n t l y d i f f e r e n t from the BA and the NH but not s i g n i f i c a n t l y d i f f e r e n t from the UBC l i n e , and the male progeny of t h i s l i n e s t i l l had the lowest mean body weight among the 4 l i n e s . At 18 days of age the male progeny of the MH s t i l l had the lowest mean, the value was not s i g n i f i c a n t l y d i f f e r e n t from the other 3 l i n e s . The MH l i n e had c o n s i s t e n t l y the lowest mean as a dam e f f e c t and t h i s gave a c o n s i s t e n t dam l i n e e f f e c t to 16 days of age. I t was of extreme i n t e r e s t to observe TABLE 6. MEAN EMBRYO WEIGHTS OF MALES AND FEMALES BY REPLICATION Mean embryo weight (gm.) Male Female R e p l i c a t i o n Days of inc u b a t i o n R e p l i c a t i o n 1 R e p l i c a t i o n 2 R e p l i c a t i o n 1 R e p l i c a t i o n 2 Male Female 1 2 6 0.33 1 0.39* 8 1.24 1.33* 1.21 1.25 1.29 1.23* 1.22 1.29* 10 2.66 2.78 2.55 2.70 2.72 2.63* 2.60 2.74* 12 5.74 5.83 5.46 5.58 5.79 5.52* 5.60 5.70 14 11.36 11.18 10.97 10.87 11.27 10.92* •11.16 11.02 16 17.64 18.57 17.24 18.01 18.10 17.63* 17.44 18.29* . 18 25.01 27.11* 24.58 26.02 26.06 25.30* 24.79 26.56* "^6 day embryos not sexed. * S i g n i f i c a n t l y d i f f e r e n t between the 4 categories of male , female, sex and r e p l i c a t i o n (P <_ 0.05). TABLE 7. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN EMBRYO WEIGHTS OF MALE PROGENY AT TWO DAY INTERVALS FROM 8 TO 18 DAYS OF INCUBATION Days of incubation Source of v a r i a t i o n d.f. 8 10 12 14 16 18 S i r e l i n e (S) 3 <0.01 0.03 0.20 0.53 0.77 7.15 Dam l i n e (D) 3 0.10* 0.36* 1.48* 3.96* 7.13* 9.56 S x D 9 0.02 0.08 0.86 1.86 4.53 8.33 R e p l i c a t i o n (R) 1 0.06* 0.11 0.07 0.25 6.99 35.30* S x R 3 0.01 0.06 0.07 0.13 2.57 1.66 ' D x R 3 <0.01 0.08 , 0.02 1.65 0.16 3.92 Residu a l 9 0.03 0.18 0.39 1.63 1.80 6.74 T o t a l 31 0.23 0.90 3.08 10.01 23.95 72.66 * S i g n i f i c a n t (P < 0.05). TABLE 8. SIRE AND DAM LINE MEAN EMBRYO WEIGHTS OF MALE PROGENY FROM 8 TO 18 DAYS OF INCUBATION Days of in c u b a t i o n Mean embryo weight (gm.) S i r e l i n e 1 Dam l i n e BA MH NH UBC BA MH NH UBC 8 1.30 a 1.30 a 1.27 a 1.29 a 1.35 3 1.20 b 1.30 3 1.30 10 2.67 a 2.73 a 2.73 a 2.75 a 2.82 a 2.54 b 2.76 a 2.76 a 12 5.75 a 5.74 a 5.92 a 5.73 a 6.10 a 5.49 b 5.82 a b 5.74 a b 14 11.09 a 11.24 a 11.44 a 11.30 a 11.65 a 10.71 b 11.45 a 11.25 3 16 18.08 a 17.90 a 18.34 a 18.10 3 18.54 a 17.38 b 18.52 a 17.99 a b 18 26.06 a 25.56 a 26.82 a 25.80 a 26.37 a 25.20 3 26.66 a 26.00 a Those means w i t h i n the same row of each s i r e or dam l i n e which carry the same s u p e r s c r i p t are not s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). - 34 -the values i n the MH s i r e l i n e s i n c e the progeny were not c o n s i s t e n t l y the lowest weighted ( w i t h the exception of a n o n - s i g n i f i c a n t d i f f e r e n c e at 16 and 18 days of age). No s i g n i f i c a n t d i f f e r e n c e was observed f o r any s i r e l i n e e f f e c t throughout the embryo age groups. T h e r e f o r e , the s i r e l i n e means completely disagreed w i t h the dam l i n e means f o r a l l ages t e s t e d . The s i g n i f i c a n t dam l i n e e f f e c t s might be due, at l e a s t i n p a r t , to d i f f e r e n c e s i n egg component t r a i t s . The means of many egg component t r a i t s f o r the BA, MH and UBC l i n e were shown by J a i n (1971) t o d i f f e r . For example the percent y o l k of the MH l i n e was 27.20. I t was the lowest and d i f f e r e d s i g n i f i c a n t l y from the BA (29.78 percent) and that of the UBC l i n e (28.75 p e r c e n t ) . S i m i l a r r e s u l t s were observed f o r y o l k s o l i d s . These d i f f e r e n c e s i n egg components should provide d i f f e r e n c e s i n n u t r i t i o n -a l environments to those embryos. The s i r e l i n e s e f f e c t could be masked. The analyses of v a r i a n c e of female progeny (Table 9) showed a c o n s i s t e n t s i g n i f i c a n t dam l i n e e f f e c t from 8 to 18 days of development except f o r 14 days of age. This was i n complete agreement w i t h the male progeny f o r a l l but the 14 days of age a n a l y s i s . The means of the female progeny (Table 10) i n g e n e r a l , showed that the progeny of the MH dam l i n e had the lowest mean which was c o n s i s t e n t f o r a l l ages. At 8 days of age the progeny of the MH dam l i n e was s i g n i f i c a n t l y d i f f e r e n t from the BA l i n e but not s i g n i f i c a n t l y d i f f e r e n t from the NH and the UBC l i n e . At 10 days of age i t was s i g n i f i c a n t l y d i f f e r e n t from the BA and UBC l i n e but not f o r the NH l i n e . At 12 days of age i t was s i g n i f i c a n t l y d i f f e r e n t from the BA TABLE 9. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN EMBRYO WEIGHTS OF FEMALE PROGENY AT TWO DAY INTERVALS FROM 8 TO 18 DAYS OF INCUBATION Days of Incubation source or v a r i a t i o n d.f. 8 10 12 14 16 18 S i r e l i n e (S) 3 0.02 0.03 0.41 0.55 0.29 5.61 Dam l i n e (D) 3 0.07* 0.23* 1.05* 1.72 5.92* 16.04* S x D 9 0.05 0.13 0.60 1.90 0.76 8.20 R e p l i c a t i o n (R) 1 0.01 0.17 0.12 0.08 4.73 16.70 S x R 3 0.02 0.19* 0.08 0.10 0.65 0.27 D x R 3 0.05* 0.02 0.09 0.71 1.66 3.43 Res i d u a l 9 0.02 0.06 0.22 1.46 2.55 9.19 T o t a l 31 0.25 0.84 2.56 6.53 16.56 59.45 * S i g n i f l e a n t (P _< 0.05). TABLE 10. SIRE AND DAM LINE MEAN EMBRYO WEIGHTS OF FEMALE PROGENY FROM 8 TO 18 DAYS OF INCUBATION Mean embryo weight (gm.) Days of i n c u b a t i o n S i r e l i n e1 Dam l i n e BA MH NH UBC BA MH NH UBC 8 10 12 1.27a 2.58a 5.41a 1.20a 2.62a 5.44a 1.213 2.67a 5.703 1.23a 2.64a 5.513 1.293 2.74a 5.80a 1.16b 2.50b 5.30b 1.22a b 2.61a b 5.53a b 1.25a b 2.66a 5.43b 14 10.85a 10.76a l l . l la 10.953 11.163 10.593 11.12a 10.813 16 17.573 17.533 17.643 17.78a 17.73b 16.97C 18.173 17.65b 18 24.99a 24.803 25.83a 25.58a 25.36a 24.13b 25.92a 25.79a Those means w i t h i n the same row of each s i r e or dam l i n e which carry the same s u p e r s c r i p t are not s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). - 37 -l i n e but not s i g n i f i c a n t l y d i f f e r e n t from the NH. l i n e or the UBC l i n e . At 14 days of age, i n t e r e s t i n g l y enough, although i t had the lowest mean the MH dam l i n e e f f e c t was not s i g n i f i c a n t l y d i f f e r e n t among any of the l i n e s f o r the female progeny, but at 16 days of age i t was s i g n i f i c a n t l y d i f f e r e n t from the other 3 l i n e s . I n a d d i t i o n at that t i m e , the BA and the UBC l i n e were s i g n i f i c a n t l y d i f f e r e n t from the NH l i n e . A g a i n , at 18 days of age the female progeny of the MR dam l i n e were s i g n i f i c a n t l y d i f -f e r e n t from the other 3 l i n e s which were not s i g n i f i c a n t l y d i f f e r e n t from each o t h e r . T h e r e f o r e , the dam e f f e c t observed from 8 to 18 days of age was a p r i n c i p a l c o n t r i b u t i o n of the "MH l i n e . As w i t h the male progeny, comparing the s i r e l i n e means there were no s i g n i f i c a n t d i f f e r e n c e s f o r s i r e l i n e s f o r the female progeny. However, the progeny o f the MH l i n e had the lowest averaged body weight at 8, 14, 16 and 18 days of age, although these d i f f e r e n c e s were not s i g n i f i c a n t . Tor the female progeny the body weight means of the MH s i r e and dam l i n e s were i n agreement as c o n t r a s t e d to the male progeny where no such agreement could be noted. S i g n i f i c a n t r e p l i c a t i o n e f f e c t s were found f o r the male progeny at 8 and 18 days of age, but no s i g n i f i c a n t d i f f e r e n c e s a t t r i b u t a b l e to r e p l i -c a t i o n f o r the female progeny was found. The r e p l i c a t i o n means are shown i n Table 6. The average body weight of a l l male progeny i n r e p l i c a t i o n 2 were c o n s i s t e n t l y higher than those of the male progeny i n r e p l i c a t i o n 1. T h i s d i f f e r e n c e was s i g n i f i c a n t at 8 and 18 days of development. Although there was no s i g n i f i c a n t e f f e c t of r e p l i c a t i o n f o r female progeny, the comparison of the female body weights i n d i c a t e d that the females of r e p l i c a t i o n 2 were - 38 -h e a v i e r than those of the females of r e p l i c a t i o n 1 w i t h the excep t i o n of 14 days of age where the d i f f e r e n c e was one tenth of a gram i n favour of the female progeny of r e p l i c a t i o n 1. Th e r e f o r e , i t would appear although i t i s not c o n s i s t e n t l y s i g n i f i c a n t there was a d e f i n i t e r e p l i c a t i o n d i f f e r -ence i n t h i s study. Embryo Growth Rates The mean embryo growth rates f o r each sex and genotypic mating r e -corded at 2-day i n t e r v a l s from 6 to 18 days of i n c u b a t i o n are shown i n Table 11 and the analyses of these embryo growth r a t e s i s presented i n Table 12. In g e n e r a l , the 3-way i n t e r a c t i o n s were n o n - s i g n i f i c a n t w i t h the exception of the s i r e x dam x sex i n t e r a c t i o n of 6-8 day embryo growth r a t e and the s i r e x dam x r e p l i c a t i o n i n t e r a c t i o n of the same growth p e r i o d . In c o n t r a s t , the 16-18 day embryo growth r a t e had the remaining 3-way i n t e r a c t i o n s s i g -n i f i c a n t ; the s i r e x sex x r e p l i c a t i o n and the dam x sex x r e p l i c a t i o n . Since none of the 3-way i n t e r a c t i o n s were s i g n i f i c a n t i n the remaining growth periods and s i n c e there was no consistency i n the s i g n i f i c a n t 3-way i n t e r -a c t i o n s i t was assumed that these s i g n i f i c a n t i n t e r a c t i o n s were not b i o -l o g i c a l l y s i g n i f i c a n t . A pooled t e s t i n g term was used to t e s t f o r the 2-way i n t e r a c t i o n s as w e l l as some of the main e f f e c t s . Only 4 out of 36 f i r s t order i n t e r a c t i o n s were s i g n i f i c a n t . Those f i r s t order i n t e r a c t i o n s which were s i g n i f i c a n t were a l s o ignored and pooled i n the e r r o r term. The s i r e l i n e e f f e c t on the embryo growth r a t e s was observed to be s i g n i f i c a n t only f o r the 8-10 day embryo growth r a t e . The dam l i n e and the r e p l i c a t i o n e f f e c t s were s i g n i f i c a n t f o r the 6-8 day embryo growth r a t e . The r e p l i c a t i o n - 39 -TABLE 11. MEAN EMBRYO GROWTH RATES AT TWO DAY INTERVALS (D) ACROSS REPLICATIONS FROM 6 TO 18 DAYS OF INCUBATION FOR MALE (M) AND FEMALE (F) PROGENY S i r e l i n e Dam l i n e BA M MH M NH M UBC M Mean M BA 6-8 4.40 4.34 4.33 3.99 3.93 3.82 3.98 3.83 4.16 4.00 8-10 3.20 3.02 3.24 3.70 3.40 3.40 3.38 3.36 3.31 3.37 10-12 4.22 4.20 4.19 3.84 4.58 4.40 3.85 4.04 4.21 4.12 12-14 4.10 4.36 4.32 4.42 3.80 3.86 4.62 4.36 4.21 4.25 14-16 3.64 3.66 3.28 3.28 3.60 3.44 3.40 3.50 3.48 3.47 16-18 2.91 2.62 3.00 3.00 3.02 3.28 3.04 3.22 2.99 3.03 MH 6-8 4.57 4.74 4.54 4.28 4.44 4.01 4.58 4.59 4.53 4.40 8-10 3.28 3.01 3.41 3.70 3.41 3.90 3.36 3.21 3.36 3.45 10-12 4.38 4.28 4.02 4.06 4.30 4.14 4.20 4.02 4.22 4.12 12-14 4.20 4.63 4.66 4.19 4.23 4.41 4.24 4.70 4.33 4.48 14-16 3.55 3.30 3.62 3.86 3.63 3.38 3.71 3.58 3.63 3.53 16-18 3.39 3.09 2.70 2.68 3.44 3.20 3.08 2.97 3.15 2.99 NH 6-8 4.55 4.30 4.48 4.18 4.36 4.15 4.42 4.26 4.45 4.22 8-10 3.30 3.36 3.34 3.30 3.36 3.61 3.43 3.39 3.36 3.42 10-12 4.10 3.82 4.30 4.34 4.12 4.06 3.93 4.25 4.11 4.12 12-14 4.28 4.68 4.14 4.63 4.55 4.58 4.57 .4.25 4.39 4.54 14-16 3.77 3.88 3.66 3.71 3.50 3.50 3.46 3.64 3.60 3.68 16-18 3.01 2.76 3.16 3.08 3.36 3.18 2.81 3.00 3.08 3.01 UBC 6-8 4.47 4.28 4. 73 4.54 4.59 4.64 4.42 4.14 4.55 4.40 8-10 3.12 3.25 3. 38 3.36 3.54 3.25 3.44 3.64 3.37 3.40 10-12 4.14 4.00 3. 79 3.78 3.98 4.02 4.16 3.88 4.02 3.92 12-14 4.44 4.38 4. 32 4.46 4.54 4.50 4.15 4.52 4.36 4.46 14-16 3.69 3.58 3. 39 3.82 3.42 3.50 3.55 3.80 3.51 3.68 16-18 3.07 3.46 3. 22 2.98 3.08 3.30 3.10 3.14 3.12 3.21 -8 4.50 4.42 4.52 4.25 4.33 4.16 4.35 4.20 4.42 4.26 i-10 3.22 3.16 3.34 3.52 3.43 3.56 3.40 3.40 3.35 3.41 '-12 4.21 4.07 4.08 4.00 4.24 4.16 4.04 4.05 4.14 4.07 -14 4.26 4.51 4.36 4.42 4.28 4.34 4.39 4.46 4.32 4.43 -16 3.66 3.60 3.49 3.66 3.54 3.45 3.53 3.63 3.55 3.59 -18 3.10 2.98 3.02 2.94 3.22 3.24 3.01 3.08 3.09 3.06 TABLE 12. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN EMBRYO GROWTH RATES AT TWO DAY INTERVALS FROM 6 TO 18 DAYS OF INCUBATION, CALCULATIONS BASED ON DIALLEL CELL MEANS Per i o d of growth (day) Source of v a r i a t i o n d.f 6-8 8-10 10-12 12-14 14-16 16-18 S i r e l i n e (S) 3 0.46 * 0.82 0.29 0.12 0.16 0.58 Dam l i n e (D) 3 ft 1.65 0.04 0.43 0.50 0.24 0.22 S x D 9 ft 1.06 0.48 1.08 1.09 ft 0.73 1.20 Sex (F) 1 ft 0.45 0.06 0.08 0.19 0.02 0.01 S x F 3 0.08 0.14 0.04 0.11 0.18 0.09 D x F 3 0.02 <0.01 0.03 0.03 0.16 0.16 S x D x F 9 ft 0.26 0.62 0.39 1.11 0.18 0.47 R e p l i c a t i o n (R) 1 ft 2.32 <0.01 0.44 0.68 ft 3.35 * 0.50 S x R 3 0.14 0.05 0.64 0.09 0.22 0.43 D x R 3 0.04 0.28 0.29 0.95 2.06 0.75 S x D x R 9 ft 0.92 0.80 0.46 0.66 0.77 0.89 F x R 1 ft 0.08 * 0.25 <0.01 <0.01 0.05 0.06 S x F x R 3 0.01 0.27 0.65 0.27 0.40 0.68* D x F x R 3 . 0.09 0.52 0.13 0.04 0.20 * 1.00 Residual 9 0.07 0.42 1.11 1.64 1.08 0.51 T o t a l 63 7.66 4.76 6.08 7.49 9.80 7.58 S i g n i f i c a n t ( P < 0.05). - 41 -e f f e c t was s i g n i f i c a n t again f o r the 14—16 and 16^3.8 day embryo growth r a t e . I n c o n t r a s t to that observed f o r body weights the on l y s i g n i f i c a n t d i f f e r e n c e i n growth r a t e of the 2 sexes occurred i n the 6^ -8 day embryo growth r a t e . This would i n d i c a t e t h a t the body weight d i f f e r e n c e s observed i n the males and females o f embryos of 8, 10, 12, 14, 16 and 18 days of age r e s u l t e d from the s i g n i f i c a n t growth r a t e measured between 6 and 8 days of embryonic age. In a d d i t i o n , one should remember that sex at 6 days of age was not recorded. Therefore, body weight d i f f e r e n c e s a t 8 days of age f o r each sex conceivably would e x i s t at 6 days of i n c u b a t i o n o r e a r l i e r . The means of embryo growth r a t e s showing the d i f f e r e n c e s between the 2 sexes, as w e l l as tha t between the 2 r e p l i c a t i o n s are shown i n Table 13. The mean 6-8 day embryo growth r a t e i n r e p l i c a t i o n 1 was s i g n i f i c a n t l y h igher than that of r e p l i c a t i o n 2. However, the mean 14-16 and 16-18 day embryo growth r a t e s o f r e p l i c a t i o n 1 were s i g n i f i c a n t l y lower than i n r e p l i -c a t i o n 2. For c o n s i s t e n c y w i t h the body weight analyses the growth r a t e s were analyzed s e p a r a t e l y f o r male and female progeny. The analyses of v a r i a n c e of mean embryo growth r a t e s of males w i t h the pooled 3-way i n t e r a c t i o n s are presented i n Table 14. The only s i g n i f i c a n t d i f f e r e n c e s t h a t were measurable i n the 6-8 day embryo growth r a t e was that of the dam l i n e e f f e c t and t h a t of the r e p l i c a t i o n e f f e c t . The 8-10 day embryo growth r a t e showed a s i g n i f i c a n t s i r e e f f e c t . There were no s i g n i f i c a n t d i f f e r e n c e s present i n the l a t e r growth s t a g e s , except f o r the s i g n i f i c a n t e f f e c t of the s i r e x TABLE 13. MEAN EMBRYO GROWTH RATES OF MALES AND FEMALES BY REPLICATION Mean growth r a t e P e r i o d of Male Female R e p l i c a t i o n growcn (day) R e p l i c a t i o n 1 R e p l i c a t i o n 2 R e p l i c a t i o n 1 R e p l i c a t i o n 2 Male Female 1 2 6-81 4.59 4.27* 4.48 4.03* 4.42 4.26* 4.53 4.15* 8-10 3.41 3.29 3.35 3.47 3.35 3.41 3.38 3.38 10-12 4,21 4.07 4.16 3.98 4.14 4.07 4.18 4.02 12-14 4.43 4.22 4.54 4.33 4.32 4.43 4.47 4.27 14-16 3.30 3.81 3.39 3.79 3.55 3.59 3.34 3.80* 16-18 2.96 3.21 3.00 3.12 3.09 3.06 2.98 3.16* 6 day embryos not sexed. S i g n i f i c a n t l y d i f f e r e n t between comparable r e s u l t s (P_< 0.05). TABLE 14. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN EMBRYO GROWTH RATES OF MALE PROGENY AT TWO DAY INTERVALS FROM 6 TO 18 DAYS OF INCUBATION Source of v a r i a t i o n d.f. Period of growth (day) 6-•8 8-•10 10-12 12-14 14-16 16-18 S i r e l i n e (S) 3 0. 24 0. 20* 0.24 0.10 0.13 0.24 Dam l i n e (D) 3 0. 79* 0. 02 0.22 0.15 0.12 0.12 S x D 9 0. 28 0. 10 0.76 1.34 0.30 0.84 R e p l i c a t i o n (R) 1 0. 76* 0. 12 0.16 0.35 2.13 0.46 S x R 3 0. 04 0. 20 0.40 0.25 0.45 1.03* D x R 3 0. 08 0. 05 0.22 0.33 1.01 0.59 Residual 9 0. 51 0. 56 0.79 1.19 1.03 0.64 T o t a l 31 2. 70 1. 26 2.79 3.71 5.18 3.91 * S i g n i f i c a n t (P <_ 0.05). - 44 -r e p l i c a t i o n i n t e r a c t i o n at 16-18 day embryo growth, r a t e . The s i r e and dam l i n e mean embryo growth r a t e s of -males i n Table 15 i n d i c a t e d that the s i g -n i f i c a n t dam l i n e e f f e c t of the male progeny was a t t r i b u t a b l e to the BA l i n e which had the lowest mean and was s i g n i f i c a n t l y d i f f e r e n t from the MH, NH and the UBC l i n e , which were not s i g n i f i c a n t l y d i f f e r e n t from each o t h e r . The s i g n i f i c a n t s i r e l i n e e f f e c t observed i n the 8~10 day embryo growth r a t e was a g a i n , a t t r i b u t a b l e to the lower growth r a t e of the BA l i n e . I t was s i g n i f i c a n t l y d i f f e r e n t from the r e s t of the 3 l i n e s which were not s i g n i f i -c a n t l y d i f f e r e n t from each o t h e r . There were no other s i g n i f i c a n t d i f f e r e n c e s i n embryonic growth r a t e f o r e i t h e r s i r e or dam l i n e f o r male progeny t h e r e -a f t e r . The analyses of the female progeny (Table 16) i n c o n t r a s t to tha t of male progeny f o r growth r a t e s showed no s i g n i f i c a n t d i f f e r e n c e s i n e i t h e r the s i r e or dam l i n e e f f e c t s f o r any growth p e r i o d t e s t e d . The o n l y s i g n i f i c a n t e f f e c t measurable was that of r e p l i c a t i o n , and i t was observable i n the 6-8 day embryo growth r a t e . I t i s i n t e r e s t i n g to n o t e , however, although they were not s i g n i f i c a n t , the growth r a t e comparisons averaged i n the s i r e and dam l i n e s (Table 17) showed the female progeny of the BA dam l i n e had the lowest 6-8 day embryo growth r a t e . A s i m i l a r e f f e c t was noted f o r the 8-10 day embryo growth r a t e where, a g a i n , the progeny of the BA s i r e s had the lowest growth r a t e . This corresponded to the same s i r e e f f e c t observed i n the male progeny i n the previous a n a l y s e s . The r e p l i c a t i o n e f f e c t w i t h i n each sex was s i g n i f i c a n t o nly f o r the 6-8 day embryo growth r a t e . T h i s r e s u l t holds true f o r both sexes. The TABLE 15. SIRE AND DAM LINE MEAN EMBRYO GROWTH RATES OF MALE PROGENY AT TWO DAY INTERVALS FROM 6 TO 18 DAYS OF INCUBATION Mean embryo growth rate P e r i o d growth of (day) S i r e l i n e1 Dam l i n e BA MH • NH UBC BA MH NH UBC 6-8 4.50a 4.52a 4.33a 4.35a 4.16b 4.53a 4.45a 4.55a 8-10 3.22b 3.34a 3.43a 3.403 3.31a 3.36a 3.36a 3.37a 10-12 4.21a 4.08a 4.24a 4.04a 4.21a 4.22a 4.11a 4.02a 12-14 4.26a 4.36a 4.28a 4.39a 4.21a 4.33a 4.39a 4.36a 14-16 3.66a 3.49a 3.54a 3.53a 3.48a 3.63a 3.60a 3.513 16-18 3.10a 3.02a 3.22a 3 . 0 la 2.99a 3.153 3.083 3.12a Those means w i t h i n the same row of each s i r e of dam l i n e which carry the same s u p e r s c r i p t are not s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). TABLE 16. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN EMBRYO GROWTH RATES OF FEMALE PROGENY AT TWO DAY INTERVALS FROM 6 TO 18 DAYS OF INCUBATION Period of growth (day) bource or variation d.f. 6-8 8-10 10-12 12-14 14-16 16-18 Sire line (S) 3 0.31 0.76 0.10 0.13 0.21 0.43 Dam line (D) 3 0.88 0.03 0.24 0.38 0.27 0.27 S x D 9 1.03 1.00 0.70 0.86 0.60 0.84 Replication (R) 1 1.65* 0.12 0.28 0.33 1.28 0.10 S x R 3 0.11 0.11 0.89 0.11 0.17 0.09 D x R 3 0.05 0.75 0.20 0.67 1.25 1.17 Residual 9 0.48 0.66 0.78 1.11 0.81 0.76 Total 31 4.51 3.45 3.21 3.58 4.60 3.66 Significant ( P_<0.05 ) . TABLE 17. SIRE AND DAM LINE MEAN EMBRYO GROWTH RATES OF FEMALE PROGENY AT TWO DAY INTERVALS FROM 6 TO 18 DAYS OF INCUBATION Mean embryo growth rate S i r e l i n e Dam l i n e P e r i o d of growth (day) BA MH NH UBC BA MH NH UBC 6-8 4.42a 4.253 4.16a 4.203 4.00a 4.403 4.22a 4.403 8-10 3.16a 3.52a 3.56a 3.40a 3.37a 3.45a 3.42a 3.40a 10-12 4.073 4.00a 4.16a 4.053 4.12a 4.12a 4.12a 3.92a 12-14 4.51a 4.42a 4.34a 4.46a 4.25a 4.48a 4.54a 4.46a 14-16 3.613 3.66a 3.45a 3.63a 3.47a 3.53a 3.68a 3.68a 16-18 2.98a 2.94a 3.24a 3.08a 3.033 2.99a 3.01a 3.22a 'Those means w i t h i n the same row of each s i r e or dam l i n e which carry the same s u p e r s c r i p t are not s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). - 48 -The mean growth r a t e of both r e p l i c a t i o n s f o r each sex i s shown i n Table 13. The 6-8 day embryo growth r a t e of r e p l i c a t i o n 2 was s i g n i f i c a n t l y lower than i n r e p l i c a t i o n 1 f o r males as w e l l as f o r females. The d i f f e r -ences of mean growth r a t e s among a l l the r e s t of the growth periods were n o n - s i g n i f i c a n t . However, a c o n s i s t e n t r e p l i c a t i o n e f f e c t was demonstrated. Averaged Embryo Growth Rates The growth r a t e s of embryos f o r v a r y i n g p e r i o d s of time i s shown i n the Appendix Table 2. The 2 day growth r a t e estimates f o r the d i f f e r e n t i n -t e r v a l s of i n c u b a t i o n were averaged to provide estimates f o r the periods beginning at 8 and ending at 12, 14, 16 and 18 days of i n c u b a t i o n , as w e l l as those f o r other s i m i l a r comparisons s t a r t i n g at 10, 12 and 14 days of age. The analyses of v a r i a n c e of these averaged growth r a t e estimates are shown i n Table 18. No second order i n t e r a c t i o n was s i g n i f i c a n t . Only the dam x r e p l i c a t i o n i n t e r a c t i o n was s i g n i f i c a n t between 8-12 and 8-16 day embryo growth r a t e s . The s i r e l i n e e f f e c t was not s i g n i f i c a n t f o r any growth p e r i o d . C o n t r a r i l y , the dam l i n e had s i g n i f i c a n t e f f e c t s f o r a l l the growth per i o d s s t u d i e d , w i t h the exception of the 8-12, 10-14, 10-18 and 14-18 day embryo growth r a t e s . No sex d i f f e r e n c e s were s i g n i f i c a n t . The r e p l i c a t i o n e f f e c t s were s i g n i f i c a n t f o r most of the growth p e r i o d s . I t can be assumed that there was a s t r o n g , c o n s i s t e n t r e p l i c a t i o n e f f e c t i n f l u e n c i n g the growth and the subsequent body weights of the embryos. The mean averaged embryo growth r a t e s are shown i n Table 19. The i n c o n s i s t e n c y of higher and lower mean embryo growth r a t e s between the 2 sexes and between the 2 r e p l i c a t i o n s makes i t d i f f i c u l t to draw any TABLE 18. SUMS OF SQUARES FROM THE ANALYSIS OF VARIANCE OF MEAN EMBRYO GROWTH RATES FOR VARYING GROWTH PERIODS, CALCULATIONS BASED ON DIALLEL CELL MEANS Period' of growth (day) Source of : v a r i a t i o n d.f. 8-12 8-14 8-16 8-18 10-14 10-16 10-18 12-16 12-18 14-18 S i r e l i n e (S) 3 0.27 0.07 0.01 0.04 0.02 0.03 0.04 0.12 0.01 0.06 Dam l i n e (D) 3 0.12 0.09* 0.10* 0.08* 0.14 0.14* 0.09 0.35* 0.24* 0.17 S x D 9 0.24 0.06 0.05 0.06 0.15 0.08 0.10 0.26 0-16 0-22 Sex (F) 1 <0 01 0.02 0.02 <0.01 <0.01 0.01 <0.01 0.09 0.02 <0.01 S x F 3 0.05 <0.01 0.02 0.01 0.02 0.02 0.02 0.04 0.02 0.07 D x F 3 <0.01 0.01. 0.01 0.01 0.02 0.03 0.03 0.04 . 0.05 0.14 S x D x F 9 0.13 0.06 0.03 <0.01 0.17 0.08 0.02 0.23 0.04 o . i i R e p l i c a t i o n (R) 1 0.11* 0.25* 0.01 0.04* 0.55* 0.01 0.07* 0.25 0.33* 1.62* S x R 3 0.16 0.04 0.02 0.01 0.10 0.04 0.03 0.04 0.28 0.01 D x R 3 0.23* <0.01 0.13* 0.02 0.07 0.10 <0.01 0.05 0.19 0.10 S x D x R 9 0.12 0.11 0.04 0.08 0.19 0.09 0.13 0.10 0.15 0.40 F x R 1 0.04 0.02 <0.01 <0.01 <0.01 0.01 0.02 0.01 0.02 0.06 S x F x R 3 0.04 0.02 0.01 0.01 0.18 0.01 0.06 0.16 0.03 0.04 D x F x R 3 0.09 0.02 0.02 0.04 0.07 <0.01 0.07 0.04 0.05 0.08 Res i d u a l 9 0.16 0.07 0.03 0.03 0.17 0.15 0.09 0.29 0.12 0.36 T o t a l 63 1.77 0.85 0.51 0.46 1.85 0.82 0.77 2.09 1.29 3.44 ft S i g n i f i c a n t (P _< 0.05). TABLE 19. MEAN EMBRYO GROWTH RATES OF MALES AND FEMALES BY REPLICATION Per i o d of growth (day) Male Mean growth rate Female Male Female R e p l i c a t i o n R e p l i c a t i o n 1 R e p l i c a t i o n 2 R e p l i c a t i o n 1 R e p l i c a t i o n 2 1 2 8-12 3.81 3.68 3.75 3.72 3.74 3.74 3.78 3.70* 8-14 4.02 3.86* 4.02 3.92 3.94 3.97 4.02 3.89* 8-16 3.84 3.85 3.86 3.89 3.84 3.87 3.85 3.87 8-18 3.66 3.72* 3.69 3.74 3.69 3.71 3.68 3.73* 10-14 4.32 4.14* 4.35 4.15 4.23 4.25 4.33 4.15* 10-16 3.98 4.03 4.03 4.03 4.00 4.03 4.00 4.03 10-18 3.72 3.83 3.77 3.80 3.78 3.79 3.75 3.82* 12-16 3.86 4.02 3.96 4.06 3.94 4.01 3.91 4.04* 12-18 3.56 3.74* 3.64 3.75 3.65 3.69 3.60 3.74 14-18 3.13 3.51* 3.20 3.45 3.32 3.32 3.16 3.48* S i g n i f i c a n t l y d i f f e r e n t between the 4 categories of male, female, sex and r e p l i c a t i o n (P <_ 0.05). - 51 -meaningful c o n c l u s i o n . The analyses of v a r i a n c e of the male embryo growth r a t e s (Table 20) showed th a t the s i g n i f i c a n t dam l i n e e f f e c t s were the averaged growth r a t e s from the 8—16 and 8-18 day embryo growth r a t e s . The comparable e f f e c t was not s i g n i f i c a n t f o r the s i r e l i n e . The r e p l i c a t i o n e f f e c t was s i g n i f i c a n t i n the 8-14, 8-18, 10-14, 10-18 and 14-18 day embryo growth r a t e s . A g a i n , i t i n d i c a t e d the strong r e p l i c a t i o n e f f e c t . The absence of a c o n s i s t e n t dam l i n e e f f e c t i n any growth p e r i o d , i n d i c a t e d a maternal e f f e c t noted i n the previous body weight a n a l y s i s was not measur-able i n the comparable growth r a t e p e r i o d s . The -mean embryo growth r a t e s f o r v a r y i n g periods of time averaged f o r the s i r e and dam l i n e s f o r the male progeny are presented i n Table 21. P r e d i c a t e d on the s i r e l i n e s there were no s i g n i f i c a n t d i f f e r e n c e s among the 4 l i n e s f o r a l l growth periods s t u d i e d w i t h the exception of the 8-18 day embryo growth r a t e i n which the mean growth r a t e of the MH and the UBC were not s i g n i f i c a n t l y d i f f e r e n t but they were s i g n i f i c a n t l y lower than the NH l i n e . The mean growth r a t e of the BA was not s i g n i f i c a n t l y d i f f e r e n t from the r e s t . On the averaged values f o r the dam l i n e s , t h e same r e s u l t s were obtained w i t h the exception of the 8-10 and 8-18 day embryo growth r a t e s . At 8-16 day embryo growth r a t e the mean growth r a t e of the BA and the UBC were not s i g n i f i c a n t l y d i f f e r e n t , but they were s i g n i f i c a n t l y lower than the MH. The mean embryo growth r a t e of the NH l i n e was not s i g n i f i c a n t l y d i f f e r e n t from the other 3 l i n e s . The mean 8-18 day embryo growth r a t e o f the BA l i n e was not s i g n i f i c a n t l y d i f f e r e n t from the UBC l i n e but i t was s i g n i f i c a n t l y lower than those of the MH and the TABLE 20. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN MALE EMBRYO GROWTH RATES FOR VARYING GROWTH PERIODS Source of v a r i a t i o n d.f. 8-•12 Period of growth I (day) 8--14 8--16 8-18 10' -14 10- 16 10-18 12-16 12-•18 14-18 S i r e l i n e (S) 3 0. 09 0 .03 0 .01 0.03 0 .01 0. 02 0.04 0.02 0. 02 0.11 Dam l i n e (D) 3 0. 04 0 .02 0 .04* 0.04* 0 .03 0. 06 0.05 0.11 0. 10 0.10 S x D 9 0. 18 0 .04 0 .03 0.02 0 .10 0. 06 0.05 0.25 0. 11 0.21 R e p l i c a t i o n (R) 1 0. 14 0 .21* <0 .01 0.02* 0 .24 0. 02 0.08 0.19 0. 26* 1.15* S x R 3 0. 10 0 .01 0 .02 0.01 0 .06 0. 01 0.05 0.14 0. 05 0.04 D x R 3 0. 02 0 .01 0 .03 0.01 0 .03 0. 08 0.02 0.05 0. 02 0.06 Residual 9 0. 20 0 .08 0 .05 0.06 0 .22 0. 18 0.15 0.26 0. 15 0.40 T o t a l 31 0. 78 0 .40 0 .19 0.20 0 .70 0. 43 0.46 1.02 0. 70 2.08 S i g n i f i c a n t (P <_ 0.05). TABLE 21. SIRE AND DAM LINE MEAN EMBRYO GROWTH RATES OF MALE PROGENY FOR VARYING GROWTH PERIODS FROM 8 TO 18 DAYS OF INCUBATION Mean embryo growth ra t e P e r i o d growth of (day) S i r e l i n e1 Dam l i n e BA MH NH UBC BA MH NH UBC 8-12 3.72a 3.71a 3.84a 3.72a 3.76a 3.803 3.74a 3.69a 8-14 8-16 8-18 3.89a 3.93a 3.84a 3.82a 3.69a b 3.66b 3.98a 3.87a 3.74a 3.94a 3.84a 3.68b 3.91a 3.80b 3.64C 3.97a 3.89a 3.74a 3.95a 3.86a b 3.71a b 3.92a 3.82b 3.68b c 10-14 4.23a 4.22a 4.26a 4.22a 4.21a 4.28a 4.25a 4.19a 10-16 4.04a 3.98a 4.02a 3.99a 3.97a 4.06a 4.03a 3.96a 10-18 12-16 3.81a a 3.96 3.74a 3.92a 3.82a 3.91a 3.74a 3.96a 3.72a 3.84a 3.83a 3.98a 3.80a 3.99a 3.75a 3.94a 12-18 3.67a 3.62a 3;68a 3.64a 3.56a 3.70a 3.69a 3.66a 14-18 3.38a 3.25a 3.38a 3.27a 3.23a 3.39a 3.34a 3.32a "'"Those means s u p e r s c r i p t w i t h i n the same row of each s i r 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 or dam l i n e which (P > 0.05). carry the same - 54 -NH l i n e . The mean embryo growth r a t e of the UBC l i n e was s i g n i f i c a n t l y lower than the "MH l i n e but was not s i g n i f i c a n t l y d i f f e r e n t from the NH l i n e , and the mean of the MH and the NH l i n e were not s i g n i f i c a n t l y d i f f e r e n t . The female progeny's analyses of v a r i a n c e are presented i n Table 22. In c o n t r a s t t o the male progeny, the female progeny had some s i g n i f i c a n t i n t e r a c t i o n e f f e c t s . However, they appeared to be q u i t e sporadic and were not c o n s i s t e n t throughout the d a t a . The r e p l i c a t i o n e f f e c t was n o n - s i g n i -f i c a n t , and s i r e x dam i n t e r a c t i o n was a l s o n o n - s i g n i f i c a n t . Table 23 shows the mean averaged female growth r a t e s based on the s i r e and dam l i n e s . As mentioned p r e v i o u s l y , there was no s i g n i f i c a n t d i f f e r e n c e among the s i r e l i n e s f o r a l l p e r i o d s of growth t e s t e d . I n the case of the dam l i n e s , i n g e n e r a l , the MH l i n e had the highest mean growth r a t e s , w h i l e the BA l i n e had the lowest mean growth r a t e . However, o n l y sporadic s i g n i f i c a n t d i f -ferences could be found. There was no s i g n i f i c a n t d i f f e r e n c e among the s i r e l i n e s f o r a l l p e r i o d s of growth s t u d i e d of female progeny (Table 2 2 ) . The averaged 8-12 and 8-10 day embryo growth r a t e s f o r the dam l i n e s were not s i g n i f i c a n t l y d i f f e r e n t . The 8-16 day embryo growth r a t e of the BA l i n e was not s i g n i f i c a n t l y d i f f e r e n t from the UBC l i n e but i t was s i g n i f i c a n t l y lower than the MH and NH l i n e . While the mean growth r a t e s of the MH, NH and UBC l i n e were not s i g n i f i c a n t l y d i f f e r e n t . The 8-18 day embryo growth r a t e and t h e r e a f t e r of the 4 l i n e s were not s i g n i f i c a n t l y d i f f e r e n t u n t i l the 12-18 day embryo growth r a t e i n which the mean growth r a t e of the MH, NH, and UBC l i n e s were not s i g n i f i c a n t l y d i f f e r e n t , but the means of the NH and UBC l i n e s were s i g n i f i c a n t l y higher than the BA l i n e . The 14-18 day TABLE 22. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN FEMALE EMBRYO GROWTH RATES FOR VARYING GROWTH PERIODS Period of growth(day) bource or v a r i a t i o n d.f. 8--12 8--14 8--16 8-•18 10-•14 10-•16 10-•18 12-•16 12-•18 14-•18 S i r e l i n e (S) 3 0. .24 0 .04 0. .02 0. 03 0. 02 0. 03 0. 01 0. 14 0. 01 0. 02 Dam l i n e (D) 3 0. .08 0 .08 0. .08* 0. 05 0. 13 0. 11 0. 07 0. 28 0. 19* 0. 20* S x D 9 0. .19 0 .09 0, .06 0. 05 0. 22 0. 10 0. 08 0. 24 0. 10 0. 11 R e p l i c a t i o n (R) 1 0, .01 0 .06 0. .01 0. 02 0. 31 <0. 01 0. 01 0. 07 0. 09 0. 53 S x R 3 0. .09 0 .05 0. .01 0. 01 0. 21* 0. 04 0. 04 0. 06 <0. 01 0. 01 D x R 3 0. ,30* 0 .01 0. ,12* 0. 04 0. 11 0. 03 0. 05 0. 04 0. 05 0. 12 Residual 9 0. .07 0 .10 0. .02 0. 05 0. 14 0. 07 0. 06 0. 13 0. 12 0. 36 T o t a l 31 0. ,99 0 .43 0. .31 0. 25 1. 14 0. 38 0. 32 0. 98 0. 56 1. 35 S i g n i f i c a n t (P <_ 0.05). TABLE 23. SIRE AND DAM MEAN EMBRYO GROWTH RATES OF FEMALE PROGENY FOR VARYING GROWTH PERIODS FROM 8 TO 18 DAYS OF INCUBATION Mean embryo growth rate P e r i o d of S i r e l i n e1 Dam l i n e growth (day) BA MH NH UBC BA MH NH UBC ' 8-12 3.62a 3.76a 3.86a 3.72a 3.74a 3.79a 3.76a 3.66a 8-14 3.92a 3.98a 4.02a 3.97a 3.91a 4.02a 4.02a 3.93a 8-16 3.84a 3.90a 3.88a 3.88a 3.80b 3.90a 3.94a 3.86a b 8-18 3.67a 3.71a 3.75a 3.72a 3.65a 3.72a 3.75a 3.74a 10-14 4.29a 4.21a 4.24a 4.25a 4.18a 4.30a 4.32a 4.19a 10-16 4.06a 4.033 3.98a 4.05a 3.95a 4.05a 4.11a 4.02a 10-18 3.79a 3.76a 3.80a 3.81a 3.72a 3.78a 3.84a 3.82a 12-16 4.06a 4.04a 3.90a 4.043 3.86a 4.01a 4.11a 4.07a 12-18 3.703 3.68a 3.68a 3.72a 3.58b 3.67a b 3.74a 3.78a 14-18 3.30a 3.30a 3.35a 3.36a 3.25b 3.26b 3.34a b 3.45a Those means w i t h i n the same row of each s i r e or dam l i n e which carry the same s u p e r s c r i p t are not s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). - 57 -embryo growth, r a t e the dam l i n e means of the BA, Jffl. and NH, were not s i g n i f i -c a n t l y d i f f e r e n t , but the mean growth r a t e of the BA and'MH l i n e were s i g n i f i -c a n t l y lower than that of the UBC l i n e which was not s i g n i f i c a n t l y d i f f e r e n t from the NH l i n e . Chick Body Weights The number of progeny evaluated i n the post embryonic data f o r each d i a l l e l mating c e l l , sex and r e p l i c a t i o n i s presented i n Appendix Table 4. There were 1,468 i n d i v i d u a l s i n the f i r s t and 1,533 i n d i v i d u a l s i n the s e -cond r e p l i c a t i o n which gave a t o t a l of 3,001 progeny f o r the experiment. The sex r a t i o was very c l o s e to 50:50. The average number of the progeny used i n each subclass was 46, but ranged from 31 to 59 i n d i v i d u a l s . The average c h i c k body weights a t weekly i n t e r v a l s from hatch to 7 weeks of age i s presented i n Table 24. The BA l i n e had the lowest averaged hatching weight f o r males (37 grams) and females (36 grams). The MH l i n e had the high e s t averaged male (41 grams) and female (40 grams) ha t c h i n g v a l u e s . However, at 7 weeks of age the NH l i n e had the highest averaged body weight of 885 grams and 718 grams f o r males and females, r e s p e c t i v e l y . The MH l i n e had the lowest average body weight of 745 grams and 614 grams f o r males and females, r e s p e c t i v e l y . The analyses of v a r i a n c e of the mean body weights are shown i n Table 25. No s i g n i f i c a n t e f f e c t of any second order i n t e r a c t i o n s i n body weights were observed, and the sources of v a r i a t i o n were pooled f o r t e s t i n g purposes. The s i r e x dam i n t e r a c t i o n was s i g n i f i c a n t f o r a l l the weekly - 58 -TABLE 24. MEAN CHICK BODY WEIGHTS OF MALES (M) AND FEMALES (F) AT WEEKLY INTERVALS FROM HATCH TO 7 WEEKS OF AGE ACROSS REPLICATIONS Sire line Dam BA MH NH UBC Mean line Week M F M F M F M F M F H 37 36 39 38 36 35 38 37 37 36 1 64 64 74 71 71 66 72 70 70 68 2 134 126 150 138 148 134 152 140 146 135 BA 3 222 206 248 218 252 222 252 226 244 218 4 340 305 372 315 386 331 383 330 370 320 5 478 420 514 426 541 455 535 448 517 437 6 630 540 669 540 708 582 698 565 676 557 7 776 656 819 651 880 712 857 683 833 675 H 40 40 41 40 40 39 41 40 40 40 1 72 68 72 72 74 74 74 72 73 71 2 147 134 143 138 150 144 149 143 147 140 MH 3 244 216 232 216 248 230 246 226 243 222 4 368 316 342 307 370 334 368 328 362 321 5 514 431 472 414 512 452 508 440 501 434 6 666 548 608 518 663 572 660 554 649 548 7 819 662 745 614 815 684 814 666 798 656 H 38 38 39 38 39 39 40 40 39 39 1 74 68 74 72 70 66 74 72 73 69 2 150 134 152 141 . 145 133 154 144 150 138 NH 3 257 224 253 228 246 220 262 234 254 226 4 391 336 380 335 377 328 396 348 386 337 5 552 467 530 459 536 454 556 472 544 463 6 722 602 692 581 710 588 730 602 714 593 7 882 732 856 701 885 718 902 723 881 719 H 40 39 41 40 40 39 40 39 40 39 1 70 68 74 72 74 70 70 68 72 69 2 147 136 148 139 152 141 145 134 148 137 UBC 3 246 217 240 217 254 228 239 216 245 220 4 372 320 356 312 386 336 362 317 369 322 5 520 438 490 421 540 459 504 434 514 438 6 684 564 636 530 711 588 660 551 673 558 7 839 682 778 637 881 715 818 660 829 674 H 39 38 40 39 38 38 40 39 39 38 1 70 67 74 72 72 69 73 70 72 69 2 144 133 148 139 149 138 150 140 148 137 Mean 3 242 215 243 220 250 225 250 226 246 221 4 368 319 362 317 380 332 377 331 372 325 5 516 439 501 430 532 455 526 448 519 443 6 676 563 651 542 698 583 687 568 678 564 7 829 683 799 651 865 707 848 683 835 681 TABLE 25. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN CHICK BODY WEIGHTS FROM HATCH TO 7 WEEKS OF AGE, CALCULATIONS BASED ON DIALLEL CELL MEANS Time of weighing (week) source or v a r i a t i o n d.f. Hatch 1 2 3 4 5 6 7 S i r e l i n e (S) 3 * 17.42 142.67 383.63 993.05 2,939.20 7,136 16,147* ft 31,117 Dam l i n e (D) 3 * 97.55 73.67 146.38 942.67 3,734.40 11,412 25,706* 44,114* S x D 9 * 11.52 ft 153.77 728.00* 2,161.80* 4,512.00* ft 7,712 11,206* 16,813* Sex (F) 1 * 6.89 ft 112.89 1,743.10* 9,925.10* 35,016.00* 91,658* 207,370* 381,150* S x F . 3 .30 4.67 18.31 28.92 29.05 99 251 919 D x F 3 .92 9.17 ft 50.31 117.80 213.30 478 * 967 904 S x D x F 9 .64 26.02 79.31 277.39 556.14 1,173 1,915 2,399 R e p l i c a t i o n (R) 1 395.02* 1,711.90* 5,365.60* 6,460.10* 11,263.00* 9,168 36,912* 1,860 S x R 3 1.17 15.92 ft 55.06 82.17 143.05 244 532 1,059 D x R 3 ft 5.55 ft 45.67 94.06* 125.55 175.55 159 386 53 S x D x R 9 10.02 35.27 62.31 94.39 165.14 361 650 1,134 F . x R 1 .14 3.52 1.00 11.39 19.14 16 214 4 S x F x R 3 .55 5.55 15.88 45.67 76.42 58 83 189 D x F x R 3 2.42 4.80 11.62 19.80 67.92 68 113 210 Residual 9 3.64 12.89 28.50 150.39 245.77 582 839 1,368 T o t a l 63 553.73 2,358.40 8,783.00 21,436.00 59,155.00 130,320 303,290 483,290 * S i g n i f i c a n t (P <. 0.05). - 60 -weights. The dam x sex i n t e r a c t i o n was s i g n i f i c a n t at 2 and 6 weeks w h i l e the s i r e x r e p l i c a t i o n i n t e r a c t i o n was s i g n i f i c a n t at 2 weeks and the dam x r e p l i c a t i o n i n t e r a c t i o n was s i g n i f i c a n t f o r the f i r s t 3 weeks of the study. These s i g n i f i c a n t e f f e c t s of the f i r s t order i n t e r a c t i o n s i n d i c a t e d t h a t i t would be a d v i s a b l e to analyse the data of the 2 r e p l i c a t i o n s as w e l l as th a t of the sexes s e p a r a t e l y . In the o v e r a l l analyses the s i r e l i n e as w e l l as the dam l i n e e f f e c t s were s i g n i f i c a n t at h a t c h , 6 and 7 weeks of age. However, the sex e f f e c t was s i g n i f i c a n t from hatch and c o n s i s t e n t l y s i g n i f i c a n t up through 7 weeks of age. The mean body weights f o r each sex are presented i n Table 26 and showed,as expected, that the d i f f e r e n c e s were i n favour of the male c h i c k s . The r e p l i c a t i o n e f f e c t was s i g n i f i c a n t f o r almost a l l of the weekly weights t e s t e d w i t h the exception of the body weights at 2, 5 and 7 weeks of age (Table 2 5). From Table 26 i t can be seen t h a t the mean body weights of the progeny i n r e p l i c a t i o n 2 were c o n s i s t e n t l y higher than those i n r e p l i c a t i o n 1 even i n those weeks t h a t d i d not demon-s t r a t e s i g n i f i c a n c e . Again the d i f f e r e n c e between the 2 r e p l i c a t i o n s was very e v i d e n t . The analyses of v a r i a n c e of the body weights of the male progeny are presented i n Table 27. The s i r e and dam l i n e e f f e c t s were s i g n i f i c a n t a t hatch and not s i g n i f i c a n t t h e r e a f t e r u n t i l 6 and 7 weeks of age f o r the dam l i n e s and at 7 weeks of age f o r the s i r e l i n e s . I t was of i n t e r e s t to note that the s i r e x dam i n t e r a c t i o n was not s i g n i f i c a n t at hatch but was s i g n i f i c a n t f o r every week t h e r e a f t e r . The r e p l i c a t i o n e f f e c t f o r the male TABLE 26. MEAN CHICK BODY WEIGHTS OF MALE AND FEMALE PROGENY BY REPLICATION Mean body weight (gm.) Time of weighing (week) Male Female Male Female R e p l i c a t i o n R e p l i c a t i o n 1 R e p l i c a t i o n 2 R e p l i c a t i o n 1 R e p l i c a t i o n 2 Hatch 37 42* 36 41* 39 38* 36 41* 1 67 77* 64 75* 72 69* 65 76* 2 138 157* 128 146* 148 137* 133 151 3 236 257* 212 231* 246 221* 224 244* 4 358 386* 312 338* 372 325* 335 362* 5 506 531* 432 455* 519 443* 469 493 6 652 704* 541 586* 678 564* 596 645* 7 • 830 840 6 75 686 835 681* 752 763 S i g n i f i c a n t l y d i f f e r e n t between comparable r e s u l t s (P < 0.05). TABLE 27. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN MALE PROGENY WEIGHTS AT WEEKLY INTERVALS FROM HATCH TO 7 WEEKS OF AGE Source of v a r i a t i o n Time of weighing (week) d.f. Hatch 1 2 3 4 5 6 7 S i r e l i n e (S) 3 10.62* 50.2 135 450 1,524 4,339 9,734 19,147* Dam l i n e (D) 3 46.62* 37.0 91 728 2,478 7,624 17,194* 28,089* S x D 9 4.62 100.2* 481* 1,757* 3,601* 6,624* 10,132* 14,367* R e p l i c a t i o n (R) 1 190.13* 780.1* 2,756* 3,507* 6,105* 4,975* 21,373* 851 S x R 3 1.12 6.1 16 31 40 39 132 . 673 D x R 3 7.12 22.4 41 48 98. 50 143 134 R e s i d u a l 9 6.62 31.4 54 206 349 700 1,097 1,973 T o t a l 31 266.88 1,027.5 3,576 6,727 14,195 24,352 59,805 65,234 * S i g n i f i c a n t (P _< 0.05). - 63 -ch i c k s was s i g n i f i c a n t at hatch., and c o n s i s t e n t l y s i g n i f i c a n t up through 6 weeks of age but not s i g n i f i c a n t at 7 weeks of age. The s i r e :x r e p l i c a -t i o n as w e l l as the dam x r e p l i c a t i o n i n t e r a c t i o n were n o n - s i g n i f i c a n t throughout the e n t i r e p e r i o d of study. Table 28 presents the mean body weights of the male progeny f o r the s i r e and dam l i n e s . The MH and the UBC l i n e s were hot s i g n i f i c a n t l y d i f f e r -ent from each other at hatching but both were s i g n i f i c a n t l y h e a v i e r than the BA and the NH l i n e . A s i m i l a r comparison e x i s t e d f o r the dam l i n e d i f f e r e n c e s . I t showed that the MH and the UBC l i n e s were not s i g n i f i c a n t l y d i f f e r e n t from each other at hatch but both were s i g n i f i c a n t l y h e a v i e r than the BA and the NH l i n e . The BA was s i g n i f i c a n t l y l i g h t e r than the NH l i n e at h a t c h i n g . The dam l i n e e f f e c t showed at 6 weeks of age the MH l i n e was the l i g h t e s t and s i g n i f i c a n t l y d i f f e r e n t from the BA and the NH l i n e but not s i g n i f i c a n t l y d i f f e r e n t from the UBC l i n e . For the same p e r i o d of time the comparable s i r e l i n e e f f e c t showed the MH l i n e a l s o had the l i g h t e s t average body weights but i t was not s i g n i f i c a n t l y d i f f e r e n t from any other l i n e . At 7 weeks of age the MH, the UBC, and the BA dam l i n e s were not s i g n i f i c a n t l y d i f f e r e n t from each other but a l l were s i g n i f i c a n t l y l i g h t e r than the NH l i n e s . I n c o n t r a s t , f o r the s i r e l i n e s the MH l i n e progeny were, a g a i n , the l i g h t e s t i n body weight and they were s i g n i f i c a n t l y d i f f e r e n t from the UBC and the BA l i n e . I n general the male progeny of the MH s i r e and dam l i n e s were not c o n s i s t e n t l y s i g n i f i c a n t l y d i f f e r e n t from the other 3 l i n e s . How-ever, s t a r t i n g at 3 weeks of age f o r the dam l i n e and 4 weeks of age f o r the TABLE 28. SIRE AND DAM LINE MEAN BODY WEIGHTS OF MALE PROGENY FROM HATCH TO 7 WEEKS OF AGE Mean body weight of chicks (gm.) Time of S i r e l i n e Dam l i n e weighing (week) BA MH NH UBC BA MH NH UBC Hatch 39b 40a 38b 40a ' 37C 40a 39b 40a 1 70a 74a 72a 73a 70 a 73a 73a 72a 2 144a 148a 149a 150a 146a 147a 150a 148a 3 242a 243a 250a 2503 244a 243a 254a 245a i 4 36 8a 362a 380a 377a 370a 362a 386a 369 a OS 5 516a 501a 532a 526a 517a 50 la 544a 514a i 6 676a 651a 698a 687a 676a 649b 714a 6 7 3a b 7 829 a b 799b 865a 848a 83 3b 79 8b 881a 829b Those means w i t h i n the same row of each s i r e or dam l i n e which carry the same s u p e r s c r i p t are not s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). - 65 -s i r e l i n e the MH males were cons i s t en t l y l i g h t e r than the progeny of the other l i n e s . In genera l , the progeny of the NH for the s i r e l i n e and dam l i n e were heav ier than the other 3 l i nes s t a r t i n g at 2 weeks of age fo r the dam l i n e , and at 4 weeks of age fo r the s i r e l i n e . The s i g n i f i c a n t i n t e r a c t i o n e f f e c t between the s i r e and dam l i nes was most i n t e r e s t i n g . I t i nd i ca t ed the unequal response i n the progeny fo r mating groups. The est imate of the s i r e , dam and i n t e r a c t i o n e f f e c t s fo r the male progeny are shown i n Table 29. I t i s evident that the s i r e x dam i n t e r a c t i o n e f f e c t of the 4 inbred l i n e s ; BA, MH, NH and UBC, i n a l l cases had h igh negat ive values whi le the major i ty of the crossbreds were p o s i t i v e . There fore , the s i g n i -f i c a n t e f f e c t of the s i r e x dam i n t e r a c t i o n shown i n Table 27 was b a s i c a l l y due to the inbred progeny. The BA purebreds cons i s t en t l y showed the greatest negat ive i n t e r a c t i o n dev ia t ion s t a r t i n g at 1 week of age. The dev ia t ion of the NH and UBC purebreds were s i m i l a r and increased over that of the MH purebreds s t a r t i n g at 2 weeks of age. The MH purebreds showed the l eas t i n t e r a c t i o n e f f e c t of the 3 l i n e s . This of course r e f l e c t s the non-addit ive genet ic con t r ibu t ion fo r body weight i n the progeny of the inbred l i n e c rosses . The analyses of var iance of body weights of the female progeny (Table 30) shows the dam e f f e c t was s i g n i f i c a n t at hatch and non-s ign i f i c an t therea f te r u n t i l 5, 6 and 7 weeks whi le the s i r e e f f e c t was non-s ign i f i c an t from hatch to 5 weeks of age but was s i g n i f i c a n t at 6 and 7 weeks of age. In genera l , th i s r e s u l t was i n agreement with the male progeny (Table 27). The - 66 -TABLE 29. SIRE, DAM AND SIRE x DAM INTERACTION EFFECTS (GM.) ON THE BODY WEIGHTS OF MALE PROGENY FROM HATCH TO 7 WEEKS OF AGE Hatch Dam e f f e c t BA MH NH UBC BA 0 1 0 0 -2 MH 0 0 1 0 1 NH -1 -1 1 0 0 UBC 0 0 1 -1 1 S i r e e f f e c t 0 1 -1 1 1 week Dam e f f e c t BA MH NH UBC BA -4 2 1 1 -2 MH 1 -3 1 0 1 NH 3 -1 -3 0 1 UBC 0 0 2 -3 0 S i r e e f f e c t -2 2 0 1 2 weeks Dam e f f e c t BA MH NH UBC BA -8 4 1 4 -2 MH 4 -4 . 2 0 -1 NH 4 2 -6 2 2 UBC 3 0 3 -5 0 S i r e e f f e c t -4 0 1 2 C o n t i n u e d - 67 -TABLE 29. (Continued) 3 weeks BA MH NH UBC e f f e c t BA -18 7 4 4 -2 MH 5 -8 1 -1 -3 NH 7 2 -12 4 8 UBC 5 -2 5 -10 -1 S i r e e f f e c t -4 -3 4 4 4 weeks Dam e f f e c t BA MH NH UBC BA -26 12 8 8 -2 MH 10 -10 0 1 -10 NH 9 4 -17 5 14 UBC 7 -3 9 -12 -3 S i r e e f f e c t -4 -10 8 5 5 weeks Dam e f f e c t BA MH NH UBC BA -36 15 11 11 " -2 MH 16 -11 -2 0 -18 NH 11 4 -21 5 25 UBC 9 -6 13 -17 -5 Si r e e f f e c t -3 -18 13 7 Continued - 68 -TABLE 29. ( C o n t i n u e d ) 6 weeks BA MH NH UBC uam e f f e c t BA -44 20 12 13 -2 MH 19 -14 -6 2 -29 NH 10 5 -24 7 36 UBC 13 -10 18 -22 -5 S i r e e f f e c t -2 -27 20 9 7 weeks Dam e f f e c t BA MH NH UBC BA -51 22 17 11 -2 MH 27 -17 -13 3 -37 NH 7 11 -26 8 46 UBC 16 -15 22 -24 -6 S i r e e f f e c t -6 . -36 30 13 TABLE 30. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN BODY WEIGHTS OF FEMALE PROGENY AT WEEKLY INTERVALS FROM HATCH TO,7 WEEKS OF AGE Source of v a r i a t i o n d.f. Time of weighing (week) Hatch 1 2 3 4 5 6 7 S i r e l i n e (S) 3 7.09 97.1 267 572 1,444 2,897 6,663* 12,889* Dam l i n e (D) 3 51.84* 45.8 106 333 1,470 4,266* 9,479* 16,929* S x D 9 7.53 79.5* 326* 682* 1,467* 2,261* 2,988* 4,845* R e p l i c a t i o n (R) 1 205.03* 935.3* 2,610* 2,964* 5,176* 4,209* 15,753* 1,012* S x R 3 0.59 15.3 54 97 179* 262 484 574 D x R 3 0.84 28.1 65 97 145* 176 356 129 Residual 9 7.03 16.8 36 39 62 242 392 529 T o t a l 31 279.97 1,218.0 3,464 4,784 9,945 14,314 36,116 36,908 ^ S i g n i f i c a n t (P <_ 0.05). - 70 -s i r e x dam i n t e r a c t i o n f o r the female progeny was i d e n t i c a l to the male progeny, i t was not s i g n i f i c a n t a t hatch But was s i g n i f i c a n t f o r every week t h e r e a f t e r . The r e p l i c a t i o n e f f e c t was s i g n i f i c a n t at hatch f o r the male progeny, and c o n s i s t e n t l y s i g n i f i c a n t up through 7 weeks of age. The female progeny a l s o showed a strong r e p l i c a t i o n e f f e c t . The s i r e x r e p l i c a t i o n i n t e r a c t i o n as w e l l as the dam x r e p l i c a t i o n i n t e r a c t i o n were n o n - s i g n i f i c a n t throughout the e n t i r e p e r i o d of study w i t h the exception of body weight at 4 weeks of age. These i n t e r a c t i o n s were probably the r e s u l t of sampling e r r o r s , s i n c e the same e f f e c t was not found i n the males a t any age l e v e l . The s i r e and dam l i n e mean body weights of the female progeny a t weekly i n -t e r v a l s from hatch to 7 weeks of age are shown i n Table 31. From hatch to 5 weeks of age a l l the means of the 4 s i r e l i n e s were not s i g n i f i c a n t l y d i f -f e r e n t . However, from hatch to 3 weeks the mean body weights of the BA s i r e l i n e was the l o w e s t , w h i l e the UBC s i r e had the highest mean body weight a t 2 and 3 weeks of age. From 4 weeks of age and t h e r e a f t e r the NH l i n e had the highest mean body weight which was analogous to the male data (Table 2 8 ). At 6 and 7 weeks of age the mean body weight of the BA, NH and the UBC s i r e l i n e s were not s i g n i f i c a n t l y d i f f e r e n t but a l l were s i g n i f i c a n t l y h e a v i e r than the MH l i n e . The MH l i n e had the lowest mean body weight at 4, 5, 6 and 7 weeks of age which was s i m i l a r to the data of the male progeny (Table 2 8 ). The mean body weight of the BA dam l i n e at hatch was the lowest and s i g n i f i -c a n t l y d i f f e r e n t from the other 3 l i n e s which themselves were not s i g n i f i -c a n t l y d i f f e r e n t . From 1 to 4 weeks of age there was no s i g n i f i c a n t d i f f e r -TABLE 31. SIRE AND DAM LINE MEAN BODY WEIGHTS OF FEMALE PROGENY FROM HATCH TO 7 WEEKS OF AGE Mean body weight of chicks (gm.) Time of S i r e l i n e1 Dam l i n e weighing (week) BA MH NH UBC BA MH NH UBC Hatch 38a 39 3 38a 3 9 a 36b 40a 39 3 39a 1 67a 72a 69a 70a 68a 71a 69a 69a 2 133a 139 a 138a 140a 135a 140 a 138a 137a 3 215a 220a 225a 226a 218a 222a 226a 2203 4 319 a 317a 332a 331a 320 3 3 2 la 337a 322a 5 439a 430a 455a 448a 437b 434b 46 3a 438b 6 56 3a ' 542b 583a 568a 557b 548b 59 3a 558b 7 683a 651b 7073 683a 675b 656b 719a 6 74b Those means w i t h i n the same row of each s i r e or dam l i n e which carry the same s u p e r s c r i p t are not s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). - 72 -ence e x i s t i n g among these 4 l i n e s . However, r e g a r d l e s s of the l a c k of s i g n i f i c a n c e , the BA dam l i n e had the lowest mean body weight from hatch up through 4 weeks of age, w h i l e the MH dam l i n e had the h e a v i e s t -mean body weight from hatch to 2 weeks of age and the NH dam l i n e had the he a v i e s t mean body weight from 3 weeks of age and was c o n s i s t e n t l y h e a v i e s t and s i g -n i f i c a n t l y so s t a r t i n g at 5 weeks and up to 7 weeks of age. In g e n e r a l , there was f a i r l y good agreement between sexes as measured by the s i r e and the dam l i n e means. The s i r e x dam i n t e r a c t i o n f o r the female progeny had a s i m i l a r response as the -male progeny. The main source of the s i r e x dam i n t e r a c t i o n f o r females, as i n the males,appeared to be due to. the e f f e c t of the matings w i t h i n the purebred l i n e s (Table 32). I t should be noted that the NH female progeny showed the h i g h e s t i n t e r a c t i o n e f f e c t as compared to the BA male progeny. Again t h i s may be f u r t h e r evidence f o r the need to separate the sexes f o r a n a l y t i c a l purposes. The mean body weights based on r e p l i c a t i o n w i t h i n each sex are l i s t e d i n Table 26. I n g e n e r a l , males and females i n r e p l i c a t i o n 1 were s i g n i f i c a n t l y l i g h t e r than the males and females i n r e p l i c a t i o n 2. This d i f f e r e n c e was observable at hat c h i n g and c o n s i s t e n t r i g h t through 7 weeks of age. However, the means at 7 weeks of age were not s i g n i f i c a n t l y d i f f e r e n t . Chick Growth Rates The mean ch i c k weekly growth r a t e s from hatch (H) to 7 weeks of age are presented i n Table 33. The analyses of vari a n c e i n Table 34 showed that o n l y 1 second order i n t e r a c t i o n was s i g n i f i c a n t ( s i r e x dam x r e p l i c a t i o n ) - 73 -TABLE 32. SIRE, DAM LINE AND SIRE x DAM LINE INTERACTION EFFECTS (GM.) ON THE BODY WEIGHTS OF FEMALE PROGENY FROM HATCH TO 7 WEEKS OF AGE Hatch Dam e f f e c t BA MH NH UBC BA 0 1 -1 0 -2 MH 0 -1 -1 -1 2 NH -1 -2 0 0 1 UBC 0 0 0 -1 1 S i re e f f e c t 0 1 0 1 1 week Dam e f f e c t BA MH NH UBC BA -2 0 -2 1 -1 MH -1 -2 3 0 2 NH 1 0 -3 2 0 UBC 4 1 0 1 -2 S i re e f f e c t -2 3 0 1 2 weeks Dam e f f e c t BA MH NH UBC BA -5 1 -2 2 -2 MH -2 -4 3 0 3 NH 0 1 -6 3 1 UBC 3 0 3 -6 0 S i re e f f e c t -4 2 1 3 Continued - 74 -TABLE 32. ( C o n t i n u e d ) 3 weeks BA MH NH UBC Dam e f f e c t BA -6 1 0 3 -3 MH 0 -5 4 -1 1 NH 4 3 -10 3 5 UBC 3 -2 4 -9 -1 S i r e e f f e c t -6 -1 4 weeks 4 5 Dam BA MH NH UBC e f f e c t BA -9 3 4 4 -5 MH 1 -6 6 1 -4 NH 5 6 -16 5 12 UBC 4 -2 7 -11 -3 S i r e e f f e c t -6 -8 5 weeks 7 6 Dam BA MH NH UBC e f f e c t BA -13 2 6 6 -6 MH 1 -7 6 7 -9 NH 8 9 -21 4 20 UBC 4 -4 9 -9 -5 S i r e e f f e c t -4 -13 12 5 C o n t i n u e d - 75 -TABLE 32. (Continued) 6 weeks BA MH NH UBC e f f e c t BA -16 5 6 4 -7 MH 1 -8 5 2 -16 NH 10 10 -24 5 29 UBC -7 -6 11 -11 -6 S i r e e f f e c t -1 -22 19 4 7 weeks Dam e f f e c t BA MH NH UBC BA -21 6 11 6 -6 MH 4 -12 2 8 -25 NH 11 12 -27 2 38 UBC 6 ' -7 15 -16 -7 S i r e e f f e c t 2 -30 26 2 - 76 -TABLE 33. MEAN CHICK GROWTH RATES OF MALES (M) AND FEMALES (F) AT WEEKLY INTERVALS ACROSS REPLICATIONS FROM HATCH TO 7 WEEKS OF AGE Sire l i n e BA MH NH UBC Mean Dam l i n e Week M F M F M F M F M BA MH NH UBC Mean H-l 1.94 1.96 2.20 2.15 2.32 2.21 2.28 2.16 2.19 2.12 1-2 3.27 3.02 3.19 3.01 3.32 3.16 3.28 3.17 3.26 3.09 2-3 2.78 2.67 2.78 2.52 2.93 2.77 2.80 2.62 2.82 2.64 3-4 2.80 2.58 2.63 2.39 2.74 2.62 2.72 2.46 2.72 2.51 4-5 2.56 2.40 2.45 2.28 2.52 2.38 2.50 2.28 2.51 2.33 5-6 2.34 2.16 2.22 2.00 2.28 2.09 2.27 1.97 2.28 2.05 6-7 1.98 1.84 1.93 1. 78 2.06 1.92 1.94 1.80 1.98 1.83 H-l 2.02 1.88 2.00 2.02 2.16 2.17 2.00 2.02 2.05 2.02 1-2 3.21 3.03 3.05 2.94 3.19 3.04 2.18 3.06 3.16 3.02 2-3 2.79 2.62 2.66 2.46 2.80 2.58 2.76 2.54 2.75 2.55 3-4 2.66 2.48 2.54 2.31 2.58 2.43 2.60 2.40 2.59 2.40 4-5 2.50 2.34 2.41 2.23 2.44 2.26 2.43 2.22 2.45 2.26 5-6 2.18 2.02 2.16 1.92 2.19 2.00 2.22 1.94 2.19 1.97 6-7 1.97 1.79 1.93 1.62 1.96 1.70 2.00 1.75 1.97 1.71 H-l 2.21 1.96 2.22 2.14 2.03 1.80 2.14 2. 05 2.15 1.99 1-2 3.23 3.12 3.20 3.04 3.28 3.16 3.30 3. 10 3.25 3.10 2-3 2.93 2.78 2.80 2.64 2.91 2.78 2.90 2. 68 2.89 2.72 3-4 2.74 2.66 2.64 2.50 2.77 2.60 2.70 2. 53 2.72 2.57 4-5 2.56 2.47 2.50 2.36 2.64 2.46 2.55 2. 30 2.56 2.40 5-6 2.30 2.14 2.27 2.00 2.38 2.18 2.30 2. 06 2.31 2.10 6-7 1.89 1.86 2.02 1.79 2.09 1.91 2.02 1. 76 2.00 1.83 H-l 2.06 1.92 2.02 1.98 2. 17 2.02 1.96 1.92 2.05 1.96 1-2 3.28 3.12 3.13 3.00 3. 24 3.12 3.22 3.04 3.22 3.06 2-3 2.82 2.59 2.66 2.45 2. 83 2.65 2.75 2.65 2.77 2.58 3-4 2.70 2.52 2.56 2.36 2. 70 2.52 2.69 2.49 2.66 2.47 4-5 2.50 2.36 2.39 2.24 2. 52 2.34 2.49 2.35 2.47 2.32 5-6 2.32 2.14 2.22 1.97 2. 32 2.10 2.30 2.02 2.29 2.06 6-7 1.94 1.80 1.93 1.73 2. 04 1.86 2.04 1.74 1.98 1.78 H-l 2.05 1.93 2.11 2.07 2.17 2.05 2.10 2.04 2.11 2.02 1-2 3.25 3.07 3.14 3.00 3.26 3.12 3.25 3.09 3.22 3.07 2-3 2.83 2.67 2.73 2.51 2.87 2.69 2.80 2.62 2.81 2.62 3-4 2.72 2.56 2.59 2.39 2.70 2.54 2.68 2.47 2.67 2.49 4-5 2.53 2.39 2.44 2.27 2.53 2.36 2.49 2.29 2.50 2.33 5-6 2.29 2.12 2.22 1.97 2.29 2.09 2.27 2.00 2.27 2.04 6-7 1.94 1.82 1.95 1.73 2.04 1.84 2.00 1.76 1.98 1.79 - 77 -f o r the RVL and 4^5 week growth r a t e s . T h e refore, a l l of the second order i n t e r a c t i o n s were pooled f o r t e s t i n g purposes. The s i r e x dam i n t e r a c t i o n f o r the weekly growth rates'HVL, 4-^ 5 and 5—6 were s i g n i f i c a n t , w h i l e the r e s t were n o n - s i g n i f i c a n t . The s i r e x sex i n t e r a c t i o n was n o n - s i g n i f i c a n t except f o r the weekly growth r a t e s of 5-6 and 6^7. No s i g n i f i c a n t e f f e c t of dam x sex i n t e r a c t i o n was observed. The presence of s i g n i f i c a n t e f f e c t s of those i n t e r a c t i o n s which contained r e p l i c a t i o n , i . e . the s i r e x r e p l i c a -t i o n and dam x r e p l i c a t i o n i n t e r a c t i o n i n d i c a t e d that i t would be a d v i s a b l e to analyse the c h i c k growth r a t e data s e p a r a t e l y f o r the 2 r e p l i c a t i o n s . A s i g n i f i c a n t s i r e l i n e as w e l l as dam l i n e e f f e c t (Table 34) was observed f o r a l l growth r a t e periods s t u d i e d w i t h the exception of the growth r a t e from H - l . T his was i n c o n t r a s t to the body weight data i n that s i r e and dam l i n e e f f e c t s although s i g n i f i c a n t at h a t c h , d i d not demonstrate s i g n i f i c a n c e again u n t i l 6 weeks of age (Table 2 5 ). The sex e f f e c t as w e l l as the r e p l i -c a t i o n e f f e c t were s i g n i f i c a n t f o r a l l periods of growth t e s t e d . T h i s i s i n agreement w i t h the body weight d a t a . The mean c h i c k growth r a t e s f o r sex and r e p l i c a t i o n s showed that the male progeny had a s i g n i f i c a n t l y f a s t e r growth r a t e than the female p r o -geny f o r each weekly growth p e r i o d (Table 3 5 ) . These sex d i f f e r e n c e s demon-s t r a t e d again that i t would be more d e s i r a b l e to analyse the data f o r each sex s e p a r a t e l y . In g e n e r a l , the progeny i n r e p l i c a t i o n 2 had a lower weekly growth r a t e than the progeny i n r e p l i c a t i o n 1 except f o r the H-l and 5-6 week growth r a t e s . As mentioned p r e v i o u s l y a l l r e p l i c a t i o n d i f f e r e n c e s were s i g -n i f i c a n t . TABLE 34. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN CHICK WEEKLY GROWTH RATES FROM HATCH TO 7 WEEKS OF AGE, CALCULATIONS BASED ON DIALLEL CELL MEANS Period of growth (week) source or V a r i a t i o n d.f. H-l 1-2 2-3 3-4 4-5 5-6 6-7 S i r e l i n e (S) 3 0.1317 0.1364* 0.2310* 0.2102* 0.1156* 0.1214* 0.0811* Dam l i n e (D) 3 0.2018 0.0843* 0.2218* 0.1956* 0.1296* 0.1387* 0.0547* S x D 9 0.4091* 0.0308 0.0340 0.0206 0.0316* 0.0283* 0.0585 Sex (F) 1 0.1156* 0.3736* 0.5366* 0.5347* 0.4591* 0.7877* 0.6006* S x F 3 0.0223 0.0037 0.0052 0.0085 0.0091 0.0248* 0.0326* D x F 3 0.0388 0.0024 0.0027 0.0100 0.0016 0.0009 0.0253 S x D x F 9 0.0431 0.0152 0.0236 0.0103 0.0095 0.0034 0-0250 R e p l i c a t i o n (R) 1 0.1369* 0.1323* 0.9168* 0.0791* 0.6360* 0.8836* 5.7961* S x R 3 0.0281 0.0115 0.0069 0.0047 0.0419* 0.0016 0-0557 D x R 3 0.0495* 0.0261* . 0.0159 0.0069 0.0238* 0-0029 0.0443 S x D x R 9 0.2145* 0.0394 0.0306 0.0128 0.0250* 0.0066 0.0179 F x R 1 0.0039 0.0088 . 0.0039 0.0002 . 0.0001 0.0005 0.0006 S x F x R 3 0.0331 0.0023 0.0038 0.0018 0 .0058 0.0021 0.0075 D x F x R 3 0.0331 0 .0032 0.0012 0.0015 0.0015 0.0007 0.0079 Residual 9 0.0371 0.0152 0.0152 0 .0150 0.0048 0.0114 0.0595 T o t a l 63 1.4986 0.8854 2.0492 1.1119 1.4949 2.0146 6.8673 S i g n i f i c a n t (P <_ 0.05). TABLE 35. MEAN CHICK GROWTH RATES OF MALE AND FEMALE PROGENY BY REPLICATION Mean growth ra t e Growth p e r i o d (week) Male Female R e p l i c a t i o n R e p l i c a t i o n 1 R e p l i c a t i o n 2 R e p l i c a t i o n 1 R e p l i c a t i o n 2 Male Female 1 2 Hatch-1 2.07 2.15 1.95 2.08 2.11 2.02* 2.01 2.11* 1-2 3.26 3.19 3.13 3.01* 3.22 3.07* 3.19 3.10* 2-3 2.92 2.70* 2.75 2.50* 2.81 2.62* 2.83 2.60* 3-4 2.71 2.64* 2.52 2.46* 2.67 2.49* 2.61 2.55* 4-5 2.60 2.40* 2.43 2.23* 2.50 2.33* 2.51 2.31* 5-6 2.15 2.39* 1.93 2.16* 2.27 2.04* 2.04 2.27* 6-7 2.29 1.68* 2.09 1.49* 1.98 1.79* 2.19 1.58* * S i g n i f i c a n t l y d i f f e r e n t between the 4 categories of male, female, sex and r e p l i c a t i o n (P <_ 0.05). - 80 -The analyses'of v a r i a n c e of weekly growth r a t e s of-males'from h a t c h to 7 weeks of age i n Table 36 showed the weekly growth r a t e s of the male progeny f o r the s i r e and dam l i n e s were s i g n i f i c a n t l y d i f f e r e n t f o r a l l p e r i o d s except f o r the H-l and 6-7 week growth r a t e s . Whereas i n c o n t r a s t to the male body weight analyses (Table 27) and the analyses f o r both sexes (Table 25) the s i r e x dam i n t e r a c t i o n s were not s i g n i f i c a n t f o r any weekly growth p e r i o d . The r e p l i c a t i o n e f f e c t was s i g n i f i c a n t f o r the 2-3 week growth r a t e and a l l subsequent weekly growth r a t e s . There were no other f i r s t order i n t e r a c t i o n s s i g n i f i c a n t w i t h the s i n g l e e x c e p t i o n of the s i r e x r e p l i c a t i o n i n t e r a c t i o n f o r the 6-7 week growth r a t e . The female progeny (Table 3 7 ) , as i n the male progeny, the H -l week growth r a t e was n o n - s i g n i f i c a n t f o r s i r e and dam l i n e s . The s i r e e f f e c t f o r a l l weekly growth p e r i o d s was s i g n i f i c a n t . The dam e f f e c t was s i g n i f i -cant s t a r t i n g at the 2-3 week growth r a t e , and i t was s i g n i f i c a n t t h e r e a f t e r . S i m i l a r l y to the male progeny, the female progeny d i d not show any s i g n i f i c a n t s i r e x dam i n t e r a c t i o n w i t h the s i n g l e exception of the 5-6 week growth r a t e . Only the 4-5 week growth r a t e showed a s i g n i f i c a n t s i r e x r e p l i c a t i o n e f f e c t . The dam x r e p l i c a t i o n e f f e c t was not s i g n i f i c a n t f o r a l l p e r i o d s t e s t e d . Contrasted to the body weight analyses i t should be pointed out that the body weight analyses were not as s e n s i t i v e i n determining l i n e e f f e c t s as was the growth r a t e a n a l y s e s . In a d d i t i o n , the separate analyses f o r each sex r e s u l t e d i n m i n i m i z i n g the s i g n i f i c a n t f i r s t and second order i n t e r a c t i o n s which were found when the sexes were combined f o r a n a l y s e s . TABLE 36. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF WEEKLY GROWTH RATES OF MALE PROGENY FROM HATCH TO 7 WEEKS OF AGE Peri o d of growth (week) source or v a r i a t i o n d.f. Hatch-1 L-2 2-3 3-4 4-5 5-6 6 -7 S i r e l i n e (S) 3 0 .06 0 .07* 0 .09* 0 .08* 0 .05* 0 .03* 0. 04 Dam l i n e (D) 3 0 .12 0, .05* 0 .09* 0 .09* 0 .06* 0 .07* <0 . 01 S x D 9 0 .25 0, .02 0 .02 0 .01 0 .02 0 .02 0. 04 R e p l i c a t i o n (R) 1 0 .05 0, .04 0 .40* 0 .04* 0 .32* 0 .46* 2. 96* S x R 3 0 .01 <0, .01 <0 .01 <0 .01 0 .03 <0 .01 0. 05* D x R 3 0 .02 0 .02 <0 .01 <0 .01 <0 .01 <0 .01 0. 04 Residual 9 0 .16 0, .04 0 .01 0 .02 <0 .01 0 .01 0. 03 T o t a l 31 0 .67 0, .24 0 .62 0 .24 0 .51 0 .60 3. 17 * S i g n i f i c a n t (P <_ 0.05). TABLE 37. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF WEEKLY GROWTH RATES OF FEMALE PROGENY FROM HATCH TO 7 WEEKS OF AGE Source of v a r i a t i o n d.f. P e r i o d of growth (week) Hatch-1 1-2 2-3 3-4 4-5 5-6 6 .-7 S i r e l i n e (S) 3 0.10 0 .07* 0.15 0.14* 0. 08* 0.12* 0. 07* Dam l i n e (D) 3 0.12 0 .03 0.13* 0.12* . 0. 07* 0.07* 0. 07* S x D 9 0.20 0 .03 0.03 0.02 0. 03 0.01* 0. 04 R e p l i c a t i o n (R) 1 0.09 0 .10* 0.52* 0.04* 0. 31* 0.42* 2. 84* S x R 3 0.05 0 .01 0.01 0.01 0. 02* 0.01 0. 02 D x R 3 0.06 0 .01 0.01 0.01 0. 01 0.01 0. 02 Residual 9 0.09 0 .02 0.03 0.01 0. 01 0.01 0. 05 T o t a l 31 0.71 0 .28 0.89 0.33 0. 53 0.63 3. 09 ^ S i g n i f i c a n t ( P j < 0 . 0 5 ) . - 83 -One can speculate about the i n t e r p r e t a t i o n of experiments, that analysed male and female body weights i n a combined a n a l y s e s , and as a consequence, determined many i n t e r a c t i o n s were p r e s e n t . I t would appear t h a t the i n t e r -a c t i o n s are nothing but the consequence of unique male and female growth r a t e d i f f e r e n c e s . The s i r e and dam l i n e mean growth r a t e s of the male progeny are presented i n Table 38, and showed the MH l i n e had the lowest mean weekly growth r a t e e i t h e r as the s i r e e f f e c t or as the dam e f f e c t . I n the m a j o r i -t y of these i n s t a n c e s i t was s i g n i f i c a n t l y d i f f e r e n t from e i t h e r 2 or 3 l i n e s . I t should be noted that the primary sources of s i g n i f i c a n c e was the mean growth r a t e of the MH l i n e . The mean growth r a t e of the female progeny .(Table 39) a l s o i n d i c a t e d that the MH l i n e was the primary source of the s i r e and dam l i n e e f f e c t i n tha t i t e x h i b i t e d g e n e r a l l y the lowest and u s u a l l y s i g n i f i c a n t weekly growth r a t e of the other 3 l i n e s . The r e -p l i c a t i o n e f f e c t w i t h i n each sex f o r weekly growth r a t e s i s shown i n Table 35. On the average, the males of r e p l i c a t i o n 1 had a s i g n i f i c a n t l y higher weekly growth r a t e than the males of r e p l i c a t i o n 2. The excep t i o n being the H - l growth r a t e ( n o n - s i g n i f i c a n t ) and the 5-6 growth r a t e ( s i g n i f i c a n t l y s m a l l e r ) . The female progeny f o l l o w e d the same p a t t e r n as d i d that of the males i n r e p l i c a t i o n 1. R e p l i c a t i o n 1 on the average had the higher weekly growth r a t e . Since i t was found as a r e p l i c a t i o n e f f e c t between, as w e l l as w i t h i n sexes i t should be noted that the 5-6 week growth r a t e was low i n r e p l i c a t i o n 1, and i n r e p l i c a t i o n 2 the 6-7 week growth r a t e was extremely TABLE 38. SIRE AND DAM LINE MEAN GROWTH RATES OF MALE PROGENY DURING WEEKLY INTERVALS FROM HATCH TO 7 WEEKS OF AGE Mean growth rate P e r i o d of growth (week) S i r e l i n e1 Dam l i n e BA MH NH UBC BA MH NH UBC Hatch-1 2.05a 2.113 2.173 2.103 2.19a 2.053 2.153 2.05a 1-2 3.25a 3.14b 3.26a 3.25a 3.26a 3.16b 3.253 3.22a 2-3 2.83a b 2.73° 2.873 2.80b 2.82b 2.75° 2.89a 2.77b C 3-4 2.72a 2.59C 2.70a b 2.68b 2.72a 2.59° 2.72a 2.66b 4-5 2.53a 2.44b 2.53a 2.49 2.51b 2.45C 2.56a 2.47b C 5-6 2.87a 2.22b 2.29a 2.27a 2.28a 2.19b 2 . 3 la 2.29a 6-7 1.94a 1.95a 2.04a 2.00a 1.983 1.97a 2.003 1.98a Those means w i t h i n the same row of each s i r e or dam l i n e which carry the same s u p e r s c r i p t are not s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). TABLE 39. SIRE AND DAM LINE MEAN GROWTH RATES OF FEMALE PROGENY DURING WEEKLY INTERVALS FROM HATCH TO 7 WEEKS OF AGE Mean growth rate P e r i o d of S i r e l i n e1 Dam l i n e growth (week) BA MH NH UBC BA MH NH UBC Hatch-1 1.933 2.073 2.053 2.053 2.12a 2.02a 1.99a 1.963 1-2 3.073 3.00b 3.123 3.09a 3.093 3.023 3.10a 3.073 2-3 2.67a 2.51b 2.69a 2.62a 2.64b 2.55° 2.72a 2.58b C 3-4 2.56a 2.39° 2.54a 2.47b 2.51b 2.40° 2.57a 2.47b 4-5 2.393 2.27b 2.36a 2.29b 2.33b 2.26° 2.40a 2.32b C 5-6 2.123 1.97b 2.09a 2.00b 2.053 1.97b 2.103 2.06a 6-7 1.82a b c 1. 73 1.84a 1. 7 6b c 1.83a 1.71b 1.83a 1.78 a b Those means w i t h i n the same row of each s i r e or dam l i n e which carry the same s u p e r s c r i p t are not s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). - 86 -low. The reason i s unknown but excluding the H-l week growth rate these are the lowest gains i n each r e p l i c a t i o n . Average Chick Growth Rates The combined growth rates of the progeny f o r each mating f o r the H-3, 1-3, 3-7, H-7 and 1-7 week growth rate are shown i n Table 40. The analyses of variance (Table 41) showed that f o r the H-3 week growth rate no f i r s t or second order i n t e r a c t i o n s were evident except that of the s i r e x dam. In f a c t the s i r e x dam i n t e r a c t i o n s were s t a t i s t i c a l l y s i g n i -f i c a n t i n the analyses of a l l combined growth periods. When the 1-3 week growth rate was tested the s i r e x sex x r e p l i c a t i o n and the s i r e x dam x r e p l i c a t i o n were both s i g n i f i c a n t . The s i r e x r e p l i c a t i o n , dam x sex, s i r e x sex f i r s t order i n t e r a c t i o n s were also s i g n i f i c a n t . The 3-7 week growth rate showed the s i r e x sex x r e p l i c a t i o n and s i r e x dam x r e p l i c a t i o n were both s i g n i f i c a n t , i n addition the s i r e x r e p l i c a t i o n , dam x sex and s i r e x sex i n t e r a c t i o n s were s i g n i f i c a n t . A l l i n t e r a c t i o n s f o r o v e r a l l growth rates H-7 and 1-7 were s i g n i f i c a n t except f o r the dam x sex x r e p l i c a t i o n , sex x r e p l i c a t i o n and dam x sex i n both t r a i t s . The data strongly suggests that sexes and r e p l i c a t i o n s need to be analysed separately. In general the s i r e l i n e s , dam l i n e s and s i r e x dam as w e l l as the sex and r e p l i c a t i o n were s i g n i f i c a n t . The s i n g l e exception was the s i r e l i n e e f f e c t f o r the H-3 week growth rate. Again the argument i s made that the analyses of the separate sexes would be d e s i r a b l e . The mean growth rates averaged by sex - 87 -TABLE 40. MEAN CHICK GROWTH RATES OF MALES (M) AND FEMALES (F) FOR VARYING GROWTH PERIODS ACROSS REPLICATIONS Sir e l i n e Dam l i n e BA MH NH UBC Mean Week M F M F M F M F M F H-3 2.66 2.56 2.73 2.56 2.86 2.72 2.79 2.65 2.76 2.62 3-7 2.42 2.24 2.30 2.11 2.40 2.26 2.36 2.13 2.37 2.18 1-3 3.02 2.85 2.98 2.76 3.12 2.96 3.04 2.90 3.04 2.87 1-7 2.62 2.44 2.53 2.32 2.64 2.50 2.59 2.38 2.60 2.41 H-7 2.52 2.38 2.48 2.30 2.60 2.45 2.54 2.35 2.54 2.37 BA MH H-3 2.68 2.52 2.56 2.47 2.72 2. 60 2.64 2.54 2.65 2.53 3-7 2.32 2.16 2.26 2.02 2.30 2. 10 2.31 2.08 2.30 2.08 1-3 3.00 2.83 2.85 2. 70 3.00 2. 81 2.98 2.80 2.96 2. 78 1-7 2.56 2.38 2.46 2.24 2.53 2. 33 2.54 2.32 2.52 2.32 H-7 2.48 2.31 2.39 2.21 2.48 2. 31 2.46 2.28 2.45 2.28 NH UBC Mean H-3 2.79 2.62 2.74 2.60 2.74 2. 58 2. 78 2.60 2. 76 2.60 3-7 2.38 2.28 2.36 2.16 2.46 2. 29 2.39 2.16 2.40 2.22 1-3 3.08 2.96 3.00 2.84 3.09 2. 96 3.10 2.88 3.07 2.91 1-7 2.61 2.50 2.57 2.39 2.68 2. 51 2.62 2.40 2.62 2.45 H-7 2.55 2.43 2.52 2.36 2.58 2. 41 2.56 2.36 2.55 2.39 H-3 2.72 2.54 2.60 2.48 2.74 2. 60 2.64 2.53 2.68 2.54 3-7 2.36 2.20 2.27 2.08 2.40 2. 20 2.38 2.14 2.35 2.16 1-3 3.06 2.86 2.90 2.72 3.04 2. 88 2.98 2.84 3.00 2.83 1-7 2.60 2.42 2.48 2.30 2.61 2. 43 2.58 2.38 2.57 2.38 H-7 2.52 2.35 2.42 2.24 2.54 2. 38 2.49 2.32 2.49 2.32 H-3 2.71 2.56 2.66 2.53 2.76 2. 62 2.71 2.58 2.71 2.57 3-7 2.37 2.22 2.30 2.09 2.39 2. 21 2.36 2.13 2.36 2.16 1-3 3.04 2.87 2.93 2.76 3.06 2. 91 3.02 2.85 3.02 2.85 1-7 2.60 2.44 2.51 2.31 2.61 2. 44 2.58 2.37 2.58 2.39 H-7 2.52 2.37 2.45 2.28 2.55 2. 39 2.51 2.32 2.51 2.34 - 88 -TABLE 41. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF CHICK GROWTH RATES FOR VARYING GROWTH PERIODS, CALCULATIONS BASED ON DIALLEL CELL MEANS Source of Period of growth (wee k) V a r i a t i o n d.f. H-3 3-7 1-3 1-7 H-7 Si r e l i n e (S) 3 0.0822 0.1189* 0.1730* 0.1338* 0.0933* Dam l i n e (D) 3 0.1236* 0.1219* 0.1304* 0.1206* 0.1120* S x D 9 0.0747* 0.0203* 0.0220* 0.0130* 0.0129* Sex (F) 1 0.3136* 0 .5929* 0.4506* 0.5439* 0.4641* S x F 3 0.0013 0.0151* 0.0010 0 .0069* 0.0032 D x F 3 0.0025 0.0035* 0.0008 0.0023 0 .0002 S x D x F 9 0.0062 0.0044 0.0091* 0.0040 0.0025 Rep l i c a t i o n (R) 1 0.1008* 0.4032* 0.4372* 0.4128* 0.2538* S x R 3 0.0006 0 .0166* 0.0088 0.0125 0.0057* D x R 3 0.0014 0 .0091 0 .0190 0.0122 0 .0049* S x D x R 9 0.0095 0.0088* 0 .0267* 0.0106* 0.0015 F x R 1 0.0010 0.0001 0.0062 0 .0003 0 .0001 S x F x R 3 0.0018 0.0038* 0.0019 0 .0014* 0.0008 D x F x R 3 0 .0024 0 .0001 0.0021 0 .0004 0.0006 Residual - 9 • 0.0050 0.0020 0.0028 0 .0004 0.0008 T o t a l 63 0.7268 1.3207 1.2916 1.2751 0.9565 S i g n i f i c a n t ( P ^ 0 . 0 5 ) . - 89 -and r e p l i c a t i o n (Table 42) showed that the female progeny had c o n s i s t e n t l y lower growth r a t e s than the male progeny, and that r e p l i c a t i o n 1 had f a s t e r growth r a t e s than r e p l i c a t i o n 2 f o r every growth p e r i o d s t u d i e d . The growth r a t e data of males were analysed s e p a r a t e l y and presented i n Table 43. For the male progeny the s i r e l i n e e f f e c t was s i g n i f i c a n t i n a l l p e r i o d s t e s t e d except f o r the H-3 week growth r a t e . The dam l i n e e f f e c t was s i g n i f i c a n t i n every growth p e r i o d s t u d i e d . This d i d not disagree w i t h the previous analyses f o r both sexes (Table 41). The s i r e x dam i n t e r a c t i o n was s i g n i f i c a n t only f o r the EV7 week growth r a t e . S i g n i f i c a n c e was ob-served i n the analyses f o r both sexes f o r t h i s one p e r i o d , however, the male progeny analysed s e p a r a t e l y d i d not show any other s i r e x dam i n t e r a c -t i o n . A s i g n i f i c a n t e f f e c t f o r a l l growth pe r i o d s was shown i n Table 41. I t appeared that the s i g n i f i c a n t s i r e x dam i n t e r a c t i o n would be b a s i c a l l y a t t r i b u t a b l e to the combined analyses of both sexes. The r e p l i c a t i o n e f f e c t , as expected, was s i g n i f i c a n t i n every p e r i o d f o r the e n t i r e study. The s i r e x r e p l i c a t i o n i n t e r a c t i o n s , as w e l l as the dam x r e p l i c a t i o n i n t e r a c t i o n s were not s i g n i f i c a n t w i t h the exception of the H-7 week growth r a t e f o r both i n t e r a c t i o n s and f o r the 3-7 week growth r a t e f o r the s i r e x r e p l i c a t i o n i n t e r a c t i o n . T his was i n good agreement w i t h the analyses f o r both sexes (Table 41). The analyses of the female progeny (Table 44) showed the s i g n i f i c a n t e f f e c t s of the s i r e and dam l i n e s occurred i d e n t i c a l l y to the analyses of the male progeny. The s i r e x dam i n t e r a c t i o n was s i g n i f i c a n t f o r the female TABLE 42. MEAN CHICK GROWTH RATES OF MALE AND FEMALE PROGENY BY REPLICATION Mean growth ra t e Growth Male Female R e p l i c a t i o n p e r i o d (week) R e p l i c a t i o n 1 R e p l i c a t i o n 2 R e p l i c a t i o n 1 R e p l i c a t i o n 2 Male Female 1 2 1-3 3.09 2.94* 2.94 2.76* 3.02 2.85* 3.01 2.85* 3-7 2.44 2,28* 2.24 2.08* 2.36 2.16* 2.34 2. 18* 1-7 2.65 2.50* 2.47 2.31* 2.58 2.39* 2.56 2.40* Hatch-3 2.75 2.68* 2.62 2.53* 2.71 2.57* 2.68 2.60* Hatch-7 2.57 2.45* 2.40 2,27 2.51 2.34* 2.48 2.36* ft S i g n i f i c a n t l y d i f f e r e n t between comparable r e s u l t s ( _ 0.05). TABLE A3. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MALE PROGENY FOR VARYING GROWTH PERIODS Source of v a r i a t i o n P e riod of growth (week) d.f. Hatch-3 3-7 1-3 1-7 Hatch-7 S i r e l i n e (S) 3 0.04 0.04* 0.08* 0.05* 0.04* Dam l i n e (D) 3 0.08* 0.04* 0.06* 0.04* 0.05* S x D 9 0.05 0.01 0.02 <0.01 <0.01 R e p l i c a t i o n (R) 1 0.04* 0.21* 0.17* 0.20* 0.12* S x R 3 <0.01 0 .01* <0,01 <0.01 <0.01* D x R 3 <0.01 <0.01 0.01 <0.01 <0.01* Res i d u a l 9 0.01 <0.01 0.01 <0.01 <0 .01 T o t a l 31 0 .22 0.33 0 .35 0.32 0.23 S i g n i f i c a n t (P < 0.05). TABLE 44. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF FEMALE PROGENY FOR VARYING GROWTH PERIODS Period of growth (week) Source of V a r i a t i o n d.f. Hatch-3 3-7 1-3 1-7 Hatch-7 S i r e l i n e (S) 3 0.04 0.10* 0.10* 0.09* 0.05* Dam l i n e (D) 3 0.05* 0.08* 0.07* 0.08* 0.06* S x D 9 0.03* 0.01 0.01 0.01 0.01* R e p l i c a t i o n (R) 1 0.06* 0.20* 0.27* 0.22* 0.13 S x R 3 <0.01 <0.01 <0.01 <0.01 <0.01 D x R 3 o . o i <0.01 <0.01 <0.01 <0.01 Residual 9 <0.01 <0.01 0.02 <0.01 <0.01 To t a l 31 0.19 0.40 0.49 0.41 0.26 * S i g n i f l e a n t (P £ 0.05). - 93 -progeny f o r the R-r-3 and UrJ week growth r a t e s . Comparison to the male data (Table 43) only the RV7 week growth r a t e was s i g n i f i c a n t . The analyses f o r both sexes (Table 41) showed a l l s i r e "x dam i n t e r a c t i o n s were s i g n i f i c a n t . A g a i n , the r e p l i c a t i o n e f f e c t was s i g n i f i c a n t i n every growth p e r i o d except f o r the H-7 week growth r a t e . No s i g n i f i c a n t e f f e c t s of s i r e x r e p l i c a t i o n and dam x r e p l i c a t i o n i n t e r a c t i o n s appeared i n the female progeny a n a l y s e s . Therefore these i n t e r a c t i o n s measurable i n the composite analyses were due to the male data shown i n Table 43. The mean growth r a t e s of the male progeny f o r the s i r e l i n e s (Table 45) shows there were no s i g n i f i c a n t d i f f e r e n c e s f o r the H-3 week growth r a t e but i t should be noted that the MH l i n e d i d have the lowest growth r a t e . For the growth r a t e of 1-3, 3-7 and 1-7 weeks the MH s i r e l i n e had the low-est means, and they were s i g n i f i c a n t l y d i f f e r e n t from the other 3 l i n e s , which were not s i g n i f i c a n t l y d i f f e r e n t . The growth of the MH f o r H-7 week growth r a t e was the lowest w h i l e the NH had the highest growth r a t e and both were s i g n i f i c a n t l y d i f f e r e n t from the BA and the UBC l i n e s which were not s i g n i f i c a n t l y d i f f e r e n t . The dam l i n e v alues gave the s i m i l a r r e s u l t s to the s i r e l i n e s , the NH dam progeny had the highest mean growth r a t e s f o r every growth p e r i o d s t u d i e d , w h i l e the MH l i n e u s u a l l y had the lowest mean growth r a t e s f o r every p e r i o d s t u d i e d . I t was of i n t e r e s t to note that the closeness of the s i r e and dam l i n e values f o r the growth r a t e a n a l y s i s , f o r example, the H-3 week growth r a t e v a l u e s ; BA: 3.04 and 3.04; MH: 2.93 and 2.96; NH: 3.04 and 3.07; UBC: 3.02 and 3.00 f o r the s i r e and dam l i n e s , r e s p e c t i v e l y . TABLE 45. SIRE AND DAM LINE MEAN GROWTH RATES OF MALE PROGENY FOR VARYING GROWTH PERIODS Mean growth r a t e P e r i o d of growth (week) S i r e 1 l i n e Dam l i n e BA MH NH UBC BA MH NH UBC 1-3 3.04a 2.93b 3.06a 3.02a 3.04a b 2.96° 3.07a 3.00b c 3-7 1-7 2.37a • 2.60a 2.30b 2.51b 2.39a 2.61a 2.36a 2.58a 2.37a 2.60a b 2.30b 2.52C 2.403 2.62a 2.353 2.57b Hatch-3 2.71a 2.65a 2.76a 2.713 2.76a 2.65b 2.76a 2.68a b Hatch-7 . 2.52b 2.45C 2.55a 2.51b 2.54a 2.45° 2.55a 2.49b Those means w i t h i n the same row of each s i r e or dam l i n e which carry the same s u p e r s c r i p t are not s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). - 95 -The s i r e and dam l i n e mean growth, r a t e s of the female progeny i n Table 46 shows, i n g e n e r a l , the p a t t e r n of d i f f e r e n c e among the l i n e s was s i m i l a r to that of the male progeny. The NH s i r e and dam l i n e progeny had the highest mean growth r a t e s and the MR s i r e and dam l i n e progeny gave the lowest mean f o r every growth p e r i o d t e s t e d . The BA, as w e l l as the UBC l i n e had the intermediate growth r a t e s , and i n g e n e r a l , were not s i g n i f i c a n t -l y d i f f e r e n t from each o t h e r , but s i g n i f i c a n t l y lower than the NH and s i g -n i f i c a n t l y higher than the MH l i n e . T his holds t r u e f o r both s i r e and dam l i n e s . Again note the extreme closeness of the values.obtained f o r the s i r e l i n e and dam l i n e f o r the 1-3 week growth r a t e . The mean growth r a t e s p r e d i c a t e d on the r e p l i c a t i o n w i t h i n each sex are given i n Table 42 and i t showed that the males as w e l l as the females i n r e p l i c a t i o n 1 had the s i g n i f i c a n t l y h i g h e r mean growth r a t e s than those i n r e p l i c a t i o n 2 f o r a l l periods s t u d i e d w i t h the exception o f the H-7 week growth r a t e of female progeny of which the excess of the mean of r e p l i c a t i o n 1 was not s i g n i f i c a n t . Pre- and Pos t - s t o r a g e Egg Weights The mean pre - and post-storage egg weights i n grams (Table 47) showed that the lowest egg weight was that from the BA l i n e and c o n s e c u t i v e l y i n c r e a s e d w i t h the NH, UBC w i t h the MH dam producing the l a r g e s t mean egg weight. This ranking held true f o r both p r e - and post-storage egg we i g h t s , which i n d i c a t e d that the r a t e of dehydration of the eggs from these 4 l i n e s was presumably very c l o s e . The analyses of vari a n c e t e s t i n g the second TABLE 46. SIRE AND DAM LINE MEAN GROWTH RATES OF FEMALE PROGENY FOR VARYING GROWTH PERIODS Mean growth rate P e r i o d of growth (week) S i r e l i n e Dam l i n e BA MH NH UBC BA MH NH UBC 1-3 2.87a b 2.76C 2.91a 2.85b 2.87a b 2.78C 2.913 2.83b C 3-7 1-7 2.22a 2.44a 2.09° 2.31° 2.21a 2.44a 2.13b 2.37b 2.18b 2.41b 2.08° 2.32° 2.22a a 2.45 2.16b 2.38b Hatch-3 2.56a 2.53a 2.62a 2.58a 2.62a 2.53b 2.603 2.54b Hatch-7 2.37a 2.28° 2.39a 2.32b 2.37a 2.28° 2.39a 2.32b Those means w i t h i n the same row of each s i r e or dam l i n e which carry the same s u p e r s c r i p t are not s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). TABLE 47. MEAN PRE- AND POST-STORAGE EGG WEIGHTS FOR THE HATCHED PROGENY OF EACH SIRE AND DAM LINE Mean egg weight (gm.) S i r e l i n e Dam l i n e BA MH NH UBC Mean BA 54.25 (53.75) 55.78 (55. 28) 54.50 (54.08) 55.95 (55.55) 55.12 (54. 66)° MH 60.00 (59.50) 60.00 (59. 60) 57.90 (57.42) 60.72 (60.22) 59.65 (59. 1 9 )3 NH 57.32 (56.82) 57.92 (57. 48) 57.98 (57.45) 58.65 (58.18) 57.97 (57. 4 8 )b UBC 59.12 (58.60) 58.58 (58. 10) 58.32 (57.85) 59.28 (58.82) 58.82 (58. 34)a l Mean 57.68 (57.57)a b 58.07 (57. 6 1 )a b 57.18 (56.70)b 58.65 (58.19)a 57.89 (57. 42) ^Post-storage egg weight bracketed. ' ' ' Those means w i t h i n the same row or column f o r pre- and post-storage egg weights which carry the same s u p e r s c r i p t are not s i g n i f i c a n t l y d i f f e r e n t (P > 0.05). - 98 -order i n t e r a c t i o n s of the egg weight data i s presented i n Table 48, and i t showed that no s i g n i f i c a n t e f f e c t f o r any second order i n t e r a c t i o n s e x i s t e d . T h e r e f o r e , i t seemed reasonable to pool these i n t e r a c t i o n s i n t o an e r r o r term. The analyses of v a r i a n c e of mean egg we i g h t s , t e s t i n g the storage e f f e c t w i t h i n each r e p l i c a t i o n , i s presented i n Table 49, and i t showed the s i g n i f i c a n t e f f e c t due to storage i n both r e p l i c a t i o n s . I t i s important to note that the t o t a l v a r i a t i o n of the egg weights of r e p l i c a t i o n 1 was higher than that of r e p l i c a t i o n 2: approximately 2 - f o l d . I t was c l e a r from the analyses of v a r i a n c e of pre- and post-storage egg weights i n Table 48 that a l l of the main e f f e c t s ; s i r e l i n e , dam l i n e and r e p l i c a t i o n were s i g n i f i c a n t and the s i r e x dam and dam x r e p l i c a t i o n e f f e c t were al s o s i g n i f i c a n t f o r both p r e - and post-storage egg weights. The s i r e x r e p l i c a t i o n i n t e r a c t i o n was s i g n i f i c a n t f o r the pre-storage egg weight but not s i g n i f i c a n t f o r the post-storage egg weight. The s i r e and dam l i n e mean egg weights are presented i n Table 47, and i t was found t h a t the BA dams which had the lowest mean egg weight was s i g n i f i c a n t l y d i f f e r e n t from the MH and NH dams. The MH dams, w i t h the highest egg weight, was a l s o s i g n i f i c a n t l y d i f f e r e n t from the NH dams. The UBC dam egg weight was not s i g n i f i c a n t l y d i f f e r e n t from e i t h e r the NH or the MH dams, but was s i g -n i f i c a n t l y d i f f e r e n t from the BA dams. The i n t e r e s t i n g s i r e source of v a r i a t i o n which was s i g n i f i c a n t i n d i c a t e d t h a t the NH and the UBC s i r e s were s i g n i f i c a n t l y d i f f e r e n t from each o t h e r , i . e . a s i g n i f i c a n t d i f f e r e n c e i n egg - 99 -TABLE 48. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF PRE-AND POST -STORAGE EGG WEIGHTS FOR HATCHED PROGENY Source of SS of egg weight v a r i a t i o n d.f. Pre-storage Post-storage S i r e l i n e 3 * 18.67 * 19.48 Dam l i n e 3 186.88* • 185.36* S x D 9 * 14.16 * 13.74 Sex (F) 1 1.02 1.00 S x F 3 0.19 0.24 D x F 3 0.36 0.32 S x D x F 9 1.92 1.85 Re p l i c a t i o n (R) 1 464.94* 441.00* S x R 3 2.52 2.50 D x R 3 * 6.64 * 7.31 S x D x R 9 0.92 0.96 F x R 1 * 1.86 * 1.96 S x F x R . 3 0.95 1.03 D x F x R 3 1.97 2.08 Residual 9 2.75 3.09 To t a l - 63 705.75 681.92 S i g n i f i c a n t (P _< 0.05). - 100 -TABLE 49. ANALYSES OF VARIANCE OF MEAN EGG WEIGHTS TESTING THE STORAGE EFFECT Source of v a r i a t i o n d.f. Sums of squares R e p l i c a t i o n 1 R e p l i c a t i o n 2 Si r e l i n e (S) 3 13.81* 10.27* Dam l i n e (D) 3 138.89* 52.91* S x D 9 9.22* 15.42* Storage (St.) 1 1.28* 2.42* S x St. 3 O.01 0.03* D x St. 3 <0.01 0.02 S x D x St. 9 0.04 0.02 T o t a l 31 163.26 . 81.09 S i g n i f i c a n t (P <_ 0.05). - 101 -weight, but neither were s i g n i f i c a n t l y d i f f e r e n t from the BA or the MH s i r e s . These r e s u l t s held true f o r both pre- and post-storage egg weights. There was no obvious evidence to explain t h i s most i n t e r e s t i n g e f f e c t . It can be speculated that the semen from the 4 male l i n e s d i d exert some i n -fluence on egg s i z e and i t possibly could be a t t r i b u t a b l e to the volume of semen used or p o s s i b l y a chemical d i f f e r e n c e existed i n the seminal f l u i d . The r e p l i c a t i o n e f f e c t f o r egg weight (Table 50) showed r e p l i c a t i o n 2 had the s i g n i f i c a n t l y higher mean egg weight than r e p l i c a t i o n 1 by approx-imately 5.4 grams f o r pre-storage egg weight and 5.2 grams f o r post-storage egg weight. The 7 week d i f f e r e n c e i n the age of the dams i n r e p l i c a t i o n 2 accounted for the la r g e r egg weight and the more v a r i a t i o n previously noted. The s i r e , dam and s i r e x dam i n t e r a c t i o n e f f e c t s expressed as deviations for pre- and post-storage egg weight are shown i n Table 51. I t can be concluded that the primary sources of s i g n i f i c a n c e of the s i r e x dam i n t e r a c t i o n i n both pre- and post storage egg weight was due to the NH s i r e s mated with the MH dams i n contrast with the NH s i r e s mated with the NH dams. The former gave an i n t e r a c t i o n e f f e c t of -1.04 grams, while the l a t t e r gave an i n t e r a c -t i o n e f f e c t of 0.73 grams i n pre-storage egg weight. The reader i s reminded that the di f f e r e n c e i n egg weight of r e p l i c a t i o n 1 and r e p l i c a t i o n 2 was probably the basic cont r i b u t i n g f a c t o r i n producing r e p l i c a t i o n d i f f e r e n c e s i n t h i s study. - 102 -TABLE 50. MEAN PRE- AND POST-STORAGE EGG WEIGHTS BY REPLICATION FOR HATCHED PROGENY Mean egg weight (gm.) Rep l i c a t i on 1 Rep l i ca t i on 2 Mean Pre-storage Post-storage 55.49* 55.09* 60.54 60.00 58.01 57.54 Mean 55.29* 60.27 57.77 A l l means i n r e p l i c a t i o n 1 were s i g n i f i c a n t l y d i f f e r e n t from r e p l i c a t i o n 2. TABLE 51. SIRE, DAM AND SIRE x DAM INTERACTION EFFECTS ON THE PRE- AND POST-STORAGE EGG WEIGHTS S i r e l i n e S i r e l i n e Dam Dam Dam : Dam l i n e BA MH NH UBC e f f e c t l i n e BA MH NH UBC e f f e c t BA -0.66 0.47 0.10- 0.07 -2.77 BA -0.66 0.43 0.14 0.12 -2.76 MH 0.55 0.16 -1.04 0.30 1.77 MH 0.58 0.24 -1.03 0.28 1.75 NH -0.44 -0.23 0.73 -0.08 0.08 NH -0.41 -0.19 0.69 -0.07 0.06 UBC 0.51 -0.42 0.22 -0.30 0.93 UBC 0.51 -0.43 0.23 -0.29 0.92 S i r e S i r e e f f e c t -0.21 0.18 -0.72 0.76 0 e f f e c t -0.25 0.19 -0.72 0.77 0 - 104 -Embryo Correlations The simple correlations of pre- and post-storage egg weights with embryo weights within each sex and r e p l i c a t i o n are presented i n Table 52. These correla t i o n c o e f f i c i e n t s were calculated based on the i n d i v i d u a l data i n which the number of observations averaged about 170 i n each sex and r e -p l i c a t i o n of every age of embryo studied. The correlations between pre-storage egg weights and embryo weights were not s i g n i f i c a n t u n t i l 18 days of incubation for males and females i n r e p l i c a t i o n 1, although they were a l l p o s i t i v e s t a r t i n g at 14 days of incubation. They were increasingly s i g n i f i -cant and p o s i t i v e at 16 and 18 days of incubation for males i n r e p l i c a t i o n 2, but no s i g n i f i c a n t correlations were observed for females i n r e p l i c a t i o n 2 at that time. However, for the females of r e p l i c a t i o n 2 at the e a r l i e r stages of development the c o r r e l a t i o n c o e f f i c i e n t s were negative but became s l i g h t l y higher and p o s i t i v e at 14 days of incubation. The presence of p o s i t i v e , s i g n i f i c a n t c o r r e l a t i o n c o e f f i c i e n t s i n t h i s study were lower than thoss reported by Deland (1965) who showed significance at 14 days of incubation and the correlation increased at 18 days of incubation for both sexes. The same results (Table 52) were observed f o r the post-storage egg weights correlated with the embryo weights, with the exception of the females i n r e p l i c a t i o n 2 which reflected the p o s i t i v e s i g n i f i c a n t c o r r e l a t i o n at 14 days of incubation and again agreed with Deland (1965). The complete lack of any i n d i c a t i o n of a correlation i n the female embryo weight and egg - 105 -TABLE 52. SIMPLE CORRELATION COEFFICIENTS OF PRE- AND POST-STORAGE EGG WEIGHTS WITH EMBRYO WEIGHTS WITHIN EACH SEX AND REPLICATION, CALCULATIONS BASED ON INDIVIDUAL DATA Days of Days of incu-bation Replication 1 Replication 2 Pre-storage Post-storage (N) P re-storage Post-storage (N) 6 1 -0.121 -0.094 (319) -0.099 -0.069 (318) 8 -0.129 -0.101 (172) -0.030 <0.000 (195) 10 -0.020 -0.015 (173) 0.080 0.120 (207) Male 12 -0.069 -0.042 (164) 0.020 0.060 (163) 14 0.030 0.061 (152) -0.024 0.014 (175) 16 0.047 0.072 (157) * 0.152 0.184* (163) * * * * 18 0.267 0.286 (160) 0.285 0.311 (157) 6 8 0.001 0.029 (148) -0.052 -Q.016 (147) 10 -0.012 0.025 (137) -0.063 -0.024 (140) Female 12 -0.059 -0.033 (146) -0.019 0.035 (161) 14 0.068 0.100 . (160) 0.121 0.170 (168) 16 0.119 0.145 (142) 0.005 0.029 (153) 18 0.297* 0.301* (147) -0.001 -0.002 (145) 6 day embryo not sexed. significant (P <_ 0.05). - 106 -weight of r e p l i c a t i o n 2, prompted further i n s p e c t i o n of the data on a dam l i n e basis f o r the post-storage data. The c o r r e l a t i o n f o r the dam of the BA l i n e was 0.59, UBC (-0.06), MH (-0.26) and NH (0.22). This ind i c a t e d that 2 dam l i n e s did agree with the male data of r e p l i c a t i o n 2. Further inspe c t i o n of the UBC and MH data indicated that 2 embryos i n each dam l i n e had extremely low body weights. The data was analysed removing these embry-os and showed the c o r r e l a t i o n f or the UBC dams to increase to 0.23. The c o r r e l a t i o n f or the MH dams increased but s t i l l did not demonstrate a p o s i t i v e r e l a t i o n s h i p (r = <-0.00). While a complete i n t e r p r e t a t i o n cannot be made from the adjusted data }the subsequent analyses indicated that the BA, UBC and NH dam l i n e s s t i l l maintain the r e l a t i o n s h i p between egg weight and embryo weight at 18 days of development. The f a i l u r e of the MH l i n e to agree with t h i s observation may be the r e s u l t of sampling e r r o r s . The o v e r a l l c o r r e l a t i o n of a l l progeny on the adjusted data showed a c o r r e l a t i o n of 0.18. Post-hatching Correlations The simple c o r r e l a t i o n c o e f f i c i e n t s of pre- and post-storage egg weights with chick body weights and growth rates within each sex and r e p l i c a -t i o n are shown i n Table 53. These c a l c u l a t i o n s were based on i n d i v i d u a l data which had 736, 730, 780 and 751 degrees of freedom f o r males and f e -males i n r e p l i c a t i o n 1 and r e p l i c a t i o n 2, r e s p e c t i v e l y . A l l of the c o r r e l a -t i o n c o e f f i c i e n t s between chick body weights and egg weights were p o s i t i v e and s i g n i f i c a n t . The c o r r e l a t i o n s between body weights at hatch and egg weights were the highest. The values averaged 0.85 for males and females TABLE' 53. SIMPLE CORRELATION COEFFICIENTS OF PRE- AND POST-STORAGE EGG WEIGHTS WITH CHICK BODY WEIGHTS AND GROWTH RATES WITHIN EACH SEX AND REPLICATION, CALCULATIONS BASED ON INDIVIDUAL DATA. R e p l i c a t i o n 1 R e p l i c a t i o n 2 Male Female Male Female Pre- Post- Pre- Post- Pre- Post- Pre- Post-d.f. 736 d.f. 730 d.f. 780 d.f. 731 Hatch 0.870* 0.863* 0.835* 0 .829* 0.910* 0 .901* 0 .894* 0 .887* 1 0.310* 0.313* 0.322* 0 .327* 0.389* 0 .395* 0 . 388* 0 .393* Chick weight 2 0.295* 0 .296* 0.329* 0 .334* 0.356* 0 .362* 0 .336* 0 . 341* (week) 3 0.255* 0.254* 0.270* 0 .273* 0 .290* 0 .294* 0 .286* 0 .288* 4 0.212* 0.211* 0.242* 0 .245* 0.229* 0 .234* 0 .243* 0 .245* 5 0.159* 0.158* 0.205* 0 .206* 0 .202* 0 .206* 0 .220* 0 .221* 6 0.139* 0.137* 0.183* 0 .183* 0.160* 0 .164* 0 .199* 0 . 200* 7 0 . I l l * 0.108* 0.162* 0 .160* 0.154* 0 .159* 0 .174* 0 .175* P e r i o d of growth Hatch-1 -0.224* -0.217* -0.199* -0 .190* -0.285* -0 .273* -0 .292* -0 .283* 1-2 -0.142* -0.143* -0.134* -o .138* -0.139* -0 .141* -0 .169* -0 .169* Chick growth 2-3 -0.141* -0.146* -0-199* -0 .205* -0-165* -0 . 170* -0 .116* -0 .121* rate (week) 3-4 -0.186* -0.188* -0.120* -0 .122* -0.176* -0 .174* -0 .135* -o .136* 4-5 -0.208* -0-211* -0-143* -0 .148* -0.076 -0 .081 -0 .064 -0 .066 5-6 -0.064 -0 .067 -0.078 -0 .082 -0.141 -0 .138* -0 .069 -0 .072 6-7 -0.130* -0.134* -0.068 -0 .077 0.001 0 .001 -0 .034 -0 .034 1-3 -0.179* -0.183* -0.207* -0 .213* -0.197* -0 .201* -0 .177* -0 .181* Average chick 3-7 -0.225* -0.229* -0.157* -0 .164* -0.178* -0 .177* -0 .137* -0 .140* growth rate 1-7 -0.243* -0.284* -0.211* -0 .219* -0.240* -0 .241* -0 .198* -0 .201* (week) Hatch-3 -0.407* -0.404* -0.434* -0 .429* -0.422* -0 .414* -0 .408* -0 .402* Hatch-7 -0.444* -0.446* -0.416* -0 .420* -0.415* -0 .409* -0 .374* -0 .372* S i g n i f i c a n t ( P j < 0 . 0 5 ) . - 108 -i n r e p l i c a t i o n 1 and 0.90 f o r males and females i n r e p l i c a t i o n 2. This i n -crease i n c o r r e l a t i o n f o r r e p l i c a t i o n 2 over r e p l i c a t i o n 1 may w e l l be the consequence of the i n c r e a s e of v a r i a b i l i t y i n egg weight noted i n Table 49. The c o r r e l a t i o n c o e f f i c i e n t s dropped by s l i g h t l y more than 1/2 at 1 week of age and continued to reduce, at a low r a t e , as the progeny became o l d e r u n t i l at 7 weeks of age the c o r r e l a t i o n c o e f f i c i e n t s averaged about 0.12 and 0.16 i n r e p l i c a t i o n 1 and r e p l i c a t i o n 2, r e s p e c t i v e l y . However, these low c o r r e l a t i o n s s t i l l w e r e . s i g n i f i c a n t which could only be determined by the l a r g e sample s i z e i n v o l v e d . The c o r r e l a t i o n s between egg weights and weekly body weights seem to be i n agreement w i t h r e p o r t s i n the l i t e r a t u r e s ( W i l e y , 1950 b; Skoglund e_t a l . , 1952; T i n d e l and M o r r i s , 1964; and Deland, 1965). Pre-storage egg weight had higher c o r r e l a t i o n s than post-storage egg weight at hatch but post-storage egg weight had higher c o r r e l a t i o n s at 1 week of age and they continued to have the higher c o r r e l a t i o n s than the pre-storage egg weight f o r at l e a s t 2 weeks t h e r e a f t e r . A l l the c o r r e l a t i o n s between egg weights and c h i c k weekly growth r a t e s were negative w i t h the exception of p r e - and post-storage egg weight w i t h 6-7 week growth r a t e of the males i n r e p l i c a t i o n 2 which had very low p o s i t i v e c o r r e l a t i o n . In g e n e r a l , the c o r r e l a t i o n s were comparatively higher at the e a r l i e r stages of growth then s l i g h t l y reduced as the progeny became o l d e r . Among the c o r r e l a t i o n s of weekly growth r a t e s and egg weights, the growth p e r i o d H-l week gave the highest value by average of -0.20 and - 109 --0.28 i n r e p l i c a t i o n 1 and r e p l i c a t i o n 2, r e s p e c t i v e l y . While these values undoubtedly are meaningful the p r o p o r t i o n of v a r i a t i o n explained was not gre a t e r than 7 percent and as a consequence egg weight d i d not exert a great i n f l u e n c e on weekly growth r a t e s . A s i m i l a r e f f e c t can be r e c a l l e d i n the r e l a t i o n s h i p of body weight at hatch and egg weight i n t h a t 72 p e r c e n t , on the average, of the v a r i a t i o n of body weight could be accounted f o r by v a r i a t i o n i n egg s i z e and, at 1 week of age t h i s r e l a t i o n s h i p dropped to 9 percent (Table 53). Considering the c o r r e l a t i o n s between the averaged growth r a t e s and egg w e i g h t s , the c o r r e l a t i o n c o e f f i c i e n t s , i n g e n e r a l , were higher than the c o r r e l a t i o n c o e f f i c i e n t s of weekly growth r a t e s w i t h egg w e i g h t s , e s p e c i a l l y f o r H-3 and H-7 week growth r a t e s which gave the c o r r e l a t i o n v alues of about -0.42 i n both growth p e r i o d s . T h i s was i n agreement between the 2 r e p l i c a -t i o n s except f o r the female progeny i n r e p l i c a t i o n 2 g i v i n g a s l i g h t l y lower c o r r e l a t i o n . These values were probably due to the h i g h simple c o r r e l a t i o n found i n the hatching weight (72 percent +). However, a l l of these c o r r e l a -t i o n s were n e g a t i v e . The simple c o r r e l a t i o n s between embryonic growth periods and c h i c k growth periods f o r each sex by r e p l i c a t i o n are shown i n Table 54,55, 56 and 57. While a complete i n t e r p r e t a t i o n d i d not appear to be evident there were some i n t e r e s t i n g r e s u l t s that should be considered. The 1-3 week growth r a t e f o r the males of r e p l i c a t i o n 1 (Table 54) had a p o s i t i v e and s i g n i f i c a n t c o r r e l a t i o n w i t h 2 embryo growth p e r i o d s : 10-12 and 14-16 day embryo growth - 110 -TABLE 54. SIMPLE CORRELATION COEFFICIENTS OF CHICK GROWTH RATES WITH EMBRYO GROWTH RATES WITHIN SEX AND REPLICATION, CALCULATIONS BASED ON DIALLEL CELL MEANS (MALE, REPLICATION 1) Embryo growth period (day) Chick growth period (week) 1-3 3-7 1-7 Hatch-3 Hatch-7 8-10 -0.284 -0.065 -0.130 -0.236 -0.169 10-12 0.551* 0.330 0.428 0.518* 0.502* 12-14 -0.520* -0.406 -0.468 -0.439 -0.494* 14-16 0.565* 0.493* 0.534* 0.335 0.476 16-18 -0.198 -0.302 -0.264 0.026 -0.149 8-12 0.386 0.301 0.360 0.377 0.407 8-14 -0.248 -0.196 -0.209 -0.133 -0.179 8-16 0.566* 0.503* 0.552* 0.352 0.499* 8-18 0.178 0.055 0.116 0.241 0.184 10-14 -0.029 -0.142 -0.106 0.048 -0.048 10-16 0.623* 0.453 0.528* 0.417 0.505* 10-18 0.299 0.092 0.178 0.336 0.258 12-16 0.127 0.159 0.146 -0.045 0.058 12-18 -0.072 -0.170 -0.136 0.011 -0.090 14-18 0.380 0.190 0.275 0.383 0.339 S i g n i f i c a n t P _< 0.05). - I l l -TABLE 55. SIMPLE CORRELATION COEFFICIENTS OF CHICK GROWTH RATES WITH EMBRYO GROWTH RATES WITHIN SEX AND REPLICATION, CALCULATIONS BASED ON DIALLEL CELL MEANS (FEMALE, REPLICATION 1) Embryo growth period (day) Chick growth period (week) i 1-3 3-7 1-7 Hatch-3 Hatch-7 8-10 0.177 -0.533* -0.040 0.040 -0,037 10-12 0.530* - 0.560* 0.570* 0.437 0.612* 12-14 -0.310 -0.291 -0.310 -0.362 -0.366 14-16 0.103 0.121 0.126 -0.088 0.072 16-18 -0.062 -0.101 -0.098 0.106 -0.037 8-12 0.528* 0.482* 0.505* 0.454 0.546* 8-14 0.105 0.092 . 0.090 -0.012 0.064 8-16 0.163 0.169 0.171 -0.088 0.106 8-18 0.102 0.076 0.080 0.015 0.074 10-14 0.088 0.129 0.118 -0.032 0.094 10-16 0.204 0.268 0.262 -0.140 0.174 10-18 0.089 0.099 0.097 -0.018 0.086 12-16 -0.186 -0.143 -0.157 -0.456 -0.274 12-18 -0.227 -0.235 -0.242 -0.279 -0.278 14-18 0.033 0.011 0.018 -0.021 0.029 S i g n i f i c a n t (P <_ 0.05). - 112 -TABLE 56. SIMPLE CORRELATION COEFFICIENTS OF CHICK GROWTH RATES WITH EMBRYO GROWTH RATES WITHIN SEX AND REPLICATION, CALCULATIONS BASED ON DIALLEL CELL MEANS (MALE, REPLICATION 2) Embryo growth p e r i o d (day) Chick growth p e r i o d (week) 1-3 3-7 1-7 Hatch-3 Hatch-7 8-10 0-118 0.301 0.245 0.371 0.398 10-12 -0-020 -0.109 -0.108 -0.055 -0.127 12-14 0.041 0.117 0.102 0.059 0.124 14-16 -0.270 -0.091 -0.194 -0.465 -0.370 16-18 0.406 -0.004 0.185 0.057 0.030 8-12 0.053 0.090 0.052 0.195 0.139 8-14 0.111 0.259 0.193 0.300 0.324 8-16 -0.150 0.116 -0.022 -0.167 -0.070 8-18 0.216 0.107 0.144 -0.111 -0.040 10-14 0.031 0.033 0.012 0.010 0.018 10-16 -0.192 -0.054 -0.148 -0.356 -0.280 10-18 0.138 -0.034 0.022 -0.243 -0.194 12-16 -0.196 0.047 -0.061 -0. 346 -0.191 12-18 0.162 0.033 0.096 -0.241 -0.135 14-18 0.142 -0.072 0.010 -0.325 -0.269 S i g n i f i c a n t (P <_ 0.05). - 113 -TABLE 57. SIMPLE CORRELATION COEFFICIENTS OF CHICK GROWTH RATES WITH EMBRYO GROWTH RATES WITHIN SEX AND REPLICATION, CALCULATIONS BASED ON DIALLEL CELL MEANS (FEMALE, REPLICATION 2) Embryo growth period (day) Chick growth period (week) 1-3 3-7 1-7 Hatch-3 Hatch-7 8-10 -0.039 -0.405 -0.286 -0.026 -0.260 10-12 -0.033 -0.172 -0.155 0.089 -0.098 12-14 o.ioi 0. 360 0.286 0.059 0.273 14-16 -0.269 -0.351 -0.311 -0.449 -0.412 16-18 0.705* 0.506* 0.59 3* 0.624* 0.603* 8-12 -0.060 -0.492* -0.374 0.048 -0.307 8-14 0.018 -0.287 -0.208 0.123 -0.132 8-16 -0.163 -0.522* -0.415 -0.184 -0.409 8-18 0.304 -0.171 -0.013 0.241 0.003 10-14 0.062 0.165 0.110 0.159 0.161 10-16 -0.134 -0.106 -0.127 -0.170 -0.150 10-18 0.365 0.257 0.296 0.267 0.278 12-16 -0.091 0.088 0.048 ' -0.250 -0.032 12-18 0.418 0.451 0.475 0.191 0.399 14-18 0.436 0.159 0.285 0.175 0.193 S i g n i f i c a n t (P_<0.05). - 114 -r a t e s . The 14-16 day embryo growth r a t e a l s o was p o s i t i v e and a s i g n i f i c a n t c o r r e l a t i o n w i t h the 3-7 week growth r a t e . Approximately 28 percent of the v a r i a t i o n i n 1-7 week1 growth r a t e could be accounted f o r by v a r i a t i o n i n 14-16 day growth r a t e . I t should be noted that a negative and s i g n i f i c a n t c o r r e l a t i o n e x i s t e d between the 12-14 day embryo growth r a t e and 1-3 week growth r a t e . The reason f o r the negative value was not evident and i t could w e l l be an a r t i f a c t or sample e r r o r w i t h i n the growth r a t e f u n c t i o n . The 8-16 day embryo growth r a t e as w e l l as the 10-16 day embryo growth r a t e were a l s o p o s i t i v e and s i g n i f i c a n t , and again a f a i r l y h i g h p r o p o r t i o n (over 25 percent) of the 1-3, 3-7 and 1-7 week growth r a t e v a r i a t i o n c o u l d be explained by v a r i a t i o n i n these embryo growth r a t e s . The r e l a t i o n s h i p of egg weight to hatching weight (Table 53) i n d i c a -ted t h a t hatching weight was not a r e l i a b l e s t a r t i n g p o i n t to measure growth r a t e s i n c e approximately 69-83 percent of the v a r i a t i o n i n hatching weight could be a s s o c i a t e d w i t h the v a r i a t i o n of egg weight over a l l sexes and r e p l i c a t i o n t e s t e d . A l s o i t was observed that i n general the h i g h e s t , nega-t i v e c o r r e l a t i o n s e x i s t e d between Hrvl week growth r a t e and egg weight, a l -though only 4-9 percent of the v a r i a t i o n could be a s s o c i a t e d w i t h the v a r i a -t i o n i n egg weight. The female progeny of r e p l i c a t i o n 1 (Table 55) showed a s l i g h t l y d i f f e r e n t response i n that only the 10-12 day embryo growth r a t e was p o s i t i v e and s i g n i f i c a n t l y a s s o c i a t e d w i t h 1-3, 3-7 and 1-7 week growth r a t e . In t h i s i n s t a n c e 32 percent of the v a r i a t i o n i n 1-7 week growth r a t e could be a s s o c i a t e d w i t h v a r i a t i o n i n 10-12 day embryo growth r a t e . The - 115 -reason f o r the s i g n i f i c a n t and negative c o r r e l a t i o n (-0.53) between 3-7 week growth r a t e and 8-10 day embryo growth r a t e was not apparent, but when one considered the 8-12 day embryo growth r a t e again approximately 25 percent of the v a r i a t i o n i n t h i s e a r l y embryonic growth was a s s o c i a t e d w i t h the subsequent growth of the c h i c k a f t e r 1 week of age. I t would appear that the pe r i o d s of time of e a r l y embryonic growth does have some sexual dimorphism i n that the 8-16 day embryo growth r a t e f o r males had the higher r e l a t i o n s h i p to 1-3, 3-7 or 1-7 week growth r a t e s , but i n the females i t was the 8-12 day p e r i o d that showed the higher a s s o c i a t i o n . T h i s should not be unexpected s i n c e the females c o n s i s t e n t l y had a s i g n i f i c a n t , lower weekly growth r a t e than the males (Table 4 0 ) . U n f o r t u n a t e l y the data of r e p l i c a t i o n 2 shows very l i t t l e evidence i f any to support the r e l a t i o n s h i p suggested f o r r e p l i c a t i o n 1. However, the reader i s reminded that to t h i s p o i n t many d i f -ferences have been shown to e x i s t between r e p l i c a t i o n 1 and r e p l i c a t i o n 2, i n f a c t every a n a l y s i s demonstrated a r e p l i c a t i o n e f f e c t : body weights and growth r a t e s f o r both embryo and c h i c k data as w e l l as egg w e i g h t s . T h i s f a i l u r e of r e p l i c a t i o n 2 to show agreement w i t h r e p l i c a t i o n 1 f o r the simple c o r r e l a t i o n s between embryo growth r a t e s and chick growth r a t e s may be ano-ther r e f l e c t i o n of these p r e v i o u s l y demonstrated d i f f e r e n c e s . The male data of r e p l i c a t i o n 2 (Table 56) d i d not show any s i g n i f i c a n t a s s o c i a t i o n s be-tween embryo growth r a t e and c h i c k growth r a t e . The female data of r e p l i c a -t i o n 2 (Table 57) d i d show a s i g n i f i c a n t , p o s i t i v e simple c o r r e l a t i o n be-tween the 16-18 day embryo growth r a t e and the growth r a t e s from 1-3, 3-7, - 116 -and 1-7 weeks. Approximately 49, 25 and 36 percent of the v a r i a t i o n i n 16-18 day embryo growth r a t e of these females was a s s o c i a t e d w i t h the sub-sequent performance at 1-3, 3-7, and 1-7 week growth r a t e s , r e s p e c t i v e l y . C onsidering the simple c o r r e l a t i o n of egg weight w i t h embryo weight (Table 52) the males of r e p l i c a t i o n 1 and 2 showed a p o s i t i v e a s s o c i a t i o n , but the c o r r e l a t i o n obtained f o r the females of r e p l i c a t i o n 2 p r a c t i c a l l y disappeared, whereas the females of r e p l i c a t i o n 1 had a strong r e l a t i o n s h i p . Table 13 shows the mean embryo growth r a t e s f o r both sexes i n each r e p l i c a -t i o n , and i t demonstrated t h a t a r e p l i c a t i o n d i f f e r e n c e i n 14-16 and 16-18 day embryo growth r a t e was measurable. The averaged -male and female embryo growth r a t e f o r these 2 per i o d s were very c l o s e ; 3.55 and 3.59 f o r the 14-16 day embryo growth r a t e , males and females, r e s p e c t i v e l y and 3.09 and 3.06 f o r the two sexes at the 16-18 day embryo growth r a t e . I n s p e c t i n g the sex response w i t h i n each r e p l i c a t i o n f o r these 2 periods showed a hi g h e r growth r a t e f o r males and females of r e p l i c a t i o n 2 over that of r e p l i c a t i o n 1 whereas p r i o r to those pe r i o d s r e p l i c a t i o n 2 had the lower embryo growth r a t e . The reason f o r t h i s r e v e r s a l was not apparent but the i n c r e a s e i n growth r a t e of r e p l i c a t i o n 2 over that of r e p l i c a t i o n 1 i n the 14-16 and 16-18 day embryo growth r a t e may w e l l be the consequence of the d i f f e r e n c e i n mean egg s i z e between r e p l i c a t i o n 1 and r e p l i c a t i o n 2: 55.29 and 60.27 grams, r e s p e c t i v e l y (Table 5 0 ). The c o r r e l a t i o n s between 7 week body weight and embryo weights as w e l l as those of the weekly body weights of the post-hatch data are shown - 117 -i n Table 58. While the estimates of the a s s o c i a t e d v a r i a t i o n s between the embryo weights and 7-week body weights was v a r i a b l e , i t was r e a d i l y noted that an e a r l y r e l a t i o n s h i p between embryo weights and 7-week body weights e x i s t e d . The male and female embryo showed a p o s i t i v e , s i g n i f i c a n t c o r r e l a -t i o n s t a r t i n g at 12 days of development i n r e p l i c a t i o n 1. In r e p l i c a t i o n 2 t h i s r e l a t i o n s h i p was s i g n i f i c a n t at 10 days of i n c u b a t i o n f o r the males and not u n t i l 14 days f o r the females. A general i n c r e a s e f o r both sexes i n each r e p l i c a t i o n was noted throughout the embryonic development, w i t h the e x c e p t i o n of the female embryos of r e p l i c a t i o n 1. However, both sexes i n each r e p l i c a t i o n had an average of s l i g h t l y more than 36 percent of the v a r i a t i o n i n 7-week body weight accounted f o r by v a r i a t i o n i n 16-day embryo body weight. In f a c t the values averaged 9, 32, 36 and 39 percent f o r 12, 14, 16 and 18 days, r e s p e c t i v e l y . I t was most i n t e r e s t i n g to note that the same l e v e l of a s s o c i a t i o n of t h i s v a r i a b i l i t y d i d not re-occur i n the post-hatched chick data u n t i l the b i r d s were at l e a s t 2 weeks of age, and at that time on the average 35 percent of the v a r i a t i o n i n 7-week body weight could be a s s o c i a t e d w i t h a 2 week body weight. (At 1 week of age the average value was 17 percent.) On the average only 2 percent of the v a r i a t i o n i n 7-week body weight could be a s s o c i a t e d w i t h h a t c h i n g weight, but as shown i n Table 53 h a t c h i n g weight was s t r o n g l y a s s o c i a t e d w i t h egg weight (approximately 78 p e r -c e n t ) . Therefore, these r e l a t i o n s h i p s would seem to p r o v i d e a s t r o n g demon-s t r a t i o n that the h a t c h i n g process i n t e r r u p t s the g e n e t i c a l l y determined body weight d i f f e r e n c e s of embryos, and not u n t i l 2 weeks a f t e r h a t c h i n g does the I - 118 -TABLE 58. SIMPLE CORRELATION COEFFICIENTS OF 7 WEEK BODY WEIGHTS WITH EMBRYO WEIGHTS AND CHICK WEIGHTS WITHIN EACH SEX AND REPLICATION 7 Week body weight Male Female R e p l i c a - R e p l i c a - R e p l i c a - R e p l i c a -t i on 1 t i on 2 t i on 1 t i o n 2 Embryo weight 6 0 .291 0 .423 0 .163 0 .393 (days of incu 8 0 .085 0 .330 -0.163 0 .440 bat ion) ca l cu 10 0 .063 0 .619* 0 .078 0.280 l a t i ons based 12 0.500* 0 .389 * 0 .522 0.266 on d i a l l e l 14 0.122 0.769* 0.291 * 0. 772 c e l l means 16 0.568* 0.663* * 0.514 0.648* 18 0.561* 0.638* 0.436 0.814* Chick weight Hatch 0 . 0 7 6 * 3 *b 0.127 *c 0.166 *d 0.182 (week) c a l c u - 1 * 0.372 0.488* 0.306* * 0.475 l a t i ons based 2 * 0.581 0.650* * 0.495 0.638* on i n d i v i d u a l 3 * 0.752 0.781* 0.679* * 0. 773 data 4 0.861* 0.839* 0.819* 0.834* 5 0.938* 0.892* 0.920* 0.882* 6 0.979* 0.912* 0.970" 0.906* 7 1.000* JL. l.poo" 1.000* 1.000* a736 degrees of freedom. b 780 degrees of freedom. C730 degrees of freedom. d 751 degrees of freedom. * S i g n i f i c a n t (P <_ 0.05) . - 119 -chick r e a d j u s t to the aforementioned r e l a t i o n s h i p . This means that the growth r a t e from H - l and 1-2 weeks were recovery phases which were d i r e c t l y r e l a -ted to egg s i z e d i f f e r e n c e s of the dam. I t i s to be noted that the greatest p r o p o r t i o n a l recovery occurred i n the H-l week grov?th r a t e . T h i s agreed very n i c e l y w i t h the i n t e r p r e t a t i o n of Bray and I t o n (1962) and Deland (1965) . The c o r r e l a t i o n s of 7-week body weights w i t h embryo growth r a t e s and c h i c k growth r a t e s are presented i n Table 59. The c a l c u l a t i o n s of these c o r r e l a t i o n s between 7-week body weights and embryo growth r a t e s were based on the d i a l l e l c e l l means, w h i l e the c o r r e l a t i o n between 7-week body weights and c h i c k growth r a t e s were c a l c u l a t e d based on the i n d i v i d u a l data w i t h 736 and 780 degrees of freedom f o r the males i n r e p l i c a t i o n 1 and r e p l i c a t i o n 2, and 730 and 751 degrees of freedom f o r the females i n r e p l i c a t i o n 1 and r e p l i c a t i o n 2, r e s p e c t i v e l y . Considering the c o r r e l a t i o n s of 7-week body weights w i t h the embryo growth r a t e s , a g a i n , the sporadic presence of nega-t i v e s i g n s and the f l u c t u a t i o n of the val u e s among the 2 sexes and r e p l i c a -t i o n s made i t d i f f i c u l t to draw any meaningful i n t e r p r e t a t i o n . However, the l a c k of any c o n s i s t e n t a s s o c i a t i o n may be a r e f l e c t i o n of the independence of the embryonic growth r a t e s from 7-week body weight. Those s i g n i f i c a n t c o r r e -l a t i o n s that appeared may be due to a chance r e l a t i o n s h i p . In f a c t one would expect no r e l a t i o n s h i p based on the growth r a t e model. In c o n t r a s t the weekly growth r a t e s a l l showed a low, p o s i t i v e s i g n i f i c a n t c o r r e l a t i o n w i t h 7-week body weight. This of course could be explained b i o l o g i c a l l y when the - 120 -TABLE 59. SIMPLE CORRELATION COEFFICIENTS OF 7 WEEK BODY WEIGHTS WITH EMBRYO GROWTH RATES AND CHICK GROWTH RATES WITHIN EACH SEX AND REPLICATION 7 Week bo Male R e p l i c a - R e p l i c a -t i o n 1 t i o n 2 w e i g h t Female R e p l i c a - R e p l i c a -t i o n 1 t i o n 2 Embryo growth 8-10 -0.070 0.503* 0.218 -0.278 p e r i o d (days 10-12 0.460 -0.367 0.518 -0.055 o f i n c u b a t i o n ) 12-14 -0.435 0.364 -0.284 0.368 c a l c u l a t i o n s 14-16 0.507* 0.553* 0.147 0.384 b a s e d on 16-18 -0.069 0.110 0.037 -0.560* d i a l l e l c e l l means 8-12 0.424 -0.033 0.730* -0.290 8-14 -0.074 0.453 0.300 -0.016 8-16 0.640* -0.130 0.353 -0.274 8-18 0.343 -0.023 0.352 0.097 10-14 -0.024 0.057 0.102 0.302 10-16 0.560* -0.391 0.268 0.014 10-18 0.360 -0.231 0.234 0.404 12-16 0.144 -0.095 -o.no 0.076 12-18 0.090 0.012 -0.067 0.488 14-18 0.458 -0.343 0.179 0.184 C h i c k growth Hatch-1 0.325*3 0.394*b 0.204*C 0.336* p e r i o d (week) 1-2 0.202* 0.210 0.170* 0.263* c a l c u l a t i o n s 2-3 0.313* 0.279* 0.288* 0.292* b a s e d on 3-4 0.155* 0.080* 0.222* 0.114* i n d i v i d u a l 4-5 0.148* 0.210* 0.193* 0.188* d a t a 5-6 0.246* 0.054 0.159* 0.081* 6-7 0.176* 0.310* 0.225* 0.328* 1-3 0.318* 0.316* 0.283* 0.347* 3-7 0.279* 0.370* 0.303* 0.403* 1-7 0.352* 0.451* 0.347* 0.490* Hatch-3 0.648* - 0.619* 0.518* 0.591* Hatch-7 0.644* 0.698* 0.598* 0. 708* 3 C ^736 degrees o f freedom. d ^ O degrees o f freedom. 780 degrees o f freedom. 751 d e g r e s s o f freedom. * S i g n i f i c a n t (P < 0.05). - 121 -environment e x e r t s an i n f l u e n c e on growth which would be expected to be r e -f l e c t e d i n 7-week body weight. Hatched c h i c k s are subjected to more and v a r i e d environmental d i f f e r e n c e s a f t e r hatching than the embryos are when developing w i t h i n an i n c u b a t o r . For example the p r e v i o u s l y demonstrated r e c o v e r i n g phase of the growth r a t e H - l week of age on the average showed 10 percent of the v a r i a t i o n i n 7-week body weight can be r e l a t e d to v a r i a -t i o n f o r that p a r t i c u l a r weeks growth. The 1-2 week growth r a t e showed on the average only 5 percent w h i l e the 2-3 week growth r a t e r e f l e c t e d 9 p e r -cent. From 3-4, 4-5 and 5-6 week growth r a t e s the averages were 2, 3 and 2 p e r c e n t , r e s p e c t i v e l y . I t was of i n t e r e s t to note that on the average 7 percent of the v a r i a b i l i t y i n 7-week body weight could be a s s o c i a t e d w i t h the v a r i a b i l i t y of 6-7 week growth r a t e . This became more meaningful when i t i s r e c a l l e d that the growth r a t e values i n r e p l i c a t i o n 1 and r e p l i c a t i o n 2 f o r the corresponding growth periods were 2.19 and 1.58, r e s p e c t i v e l y (Table 3 5 ) . T his depressed growth r a t e i n r e p l i c a t i o n 2 was f u r t h e r r e f l e c -ted i n the average percent v a r i a t i o n of 7-week body weight of r e p l i c a t i o n 2, i n that 10 percent of the v a r i a t i o n could be e x p l a i n e d . In c o n t r a s t , only 4 percent could be a s s o c i a t e d w i t h the same v a r i a b l e s i n r e p l i c a t i o n 1. T h e r e f o r e , w h i l e i t may not completely f i t the model of independence between growth r a t e and body weight, growth r a t e c e r t a i n l y takes i n t o account, i n a p r e c i s e f a s h i o n , the environmental i n f l u e n c e s , and r e f l e c t s a d i f f e r e n t measurement of the i n f l u e n c e of these environments. - 122 -The 1-3; 3-7 as w e l l as the 1-7 week growth r a t e s showed on the average 10, 12 and 17 percent of the v a r i a t i o n i n 7-week body weight could be a s s o c i a t e d w i t h the v a r i a t i o n i n these 3 t r a i t s , r e s p e c t i v e l y (Table 5 9 ). Since no comparable data e x i s t s i n the l i t e r a t u r e s f o r these values i t would be d i f f i c u l t to say i f they are too high or w i t h i n a range that was reasonable. I t should be noted that again r e p l i c a t i o n s f o r 3-7 as w e l l as 1-7 week growth r a t e s on the average showed about 15 percent and 22 percent of a s s o c i a t e d v a r i a b i l i t y w i t h 7-week body weights which was much h i g h e r than seen f o r r e p l i c a t i o n 1 f o r the same r e s p e c t i v e p e r i o d s : . 8 and 12 perc e n t . The adverse e f f e c t of H - l week growth r a t e , as a consequence of the egg s i z e r e l a t i o n s h i p , was again demonstrated when on the average 36 percent (H-3 week growth r a t e ) and 44 percent (H-7 week growth r a t e ) of the v a r i a t i o n was accounted f o r between these v a r i a b l e s and 7-week body weight. So the a d d i t i o n of ha t c h i n g weight to the growth r a t e value would appear to be de-t r i m e n t a l to the i n t e n t of m i n i m i z i n g the c o r r e l a t i o n s between growth r a t e and body weight. M u l t i p l e L i n e a r Regressions of 7-Week Body Weights 2 Table 60 presents the c o e f f i c i e n t s of determination (R ) as a percent of the m u l t i p l e l i n e a r r e g r e s s i o n of 7-week body weight, w i t h i n each sex and 2 r e p l i c a t i o n , regressed on s e v e r a l s e l e c t e d t r a i t s . The R values i n d i c a t e the percentage of the v a r i a t i o n of the dependent v a r i a b l e t h a t can be a s s o -c i a t e d w i t h the m u l t i p l e regressed independent v a r i a b l e s . The s e l e c t e d v a r i a b l e s i n t h i s study were d i v i d e d i n t o 2 groups. The f i r s t t e s t e d group i i TABLE 60. COEFFICIENTS OF DETERMINATION (100R ) OF THE INDIVIDUAL ESTIMATES OF 7 WEEK BODY WEIGHTS WITHIN EACH SEX AND REPLICATION MULTIPLE REGRESSED ON SELECTED TRAITS 7 Week body weight R e p l i c a t i o n 1 R e p l i c a t i o n 2 Male Female Male Female Selected t r a i t s d.f.-736 d.f.730 d.f.-780 d.f.-751 Hatch weight Hatch-3 3-7 Hatch-7 + + + + 1 Week weight + + + + + + + + 1-3 + + + + + + + + 3-7 + + + + 1-7 + 91.4 66.6 65.1 10.0 52.6 0.6 42.0 7.8 41.5 97.2 92.8 65.1 50.3 12.9 13.8 10.1 7.8 11.7 89.6 61.7 56.4 13.8 42 2 26 9 33.2 96.6 91.2 57.3 48.1 12.1 9.4 8.0 9.2 10.5 92.8 75.6 63.0 17.7 54.9 1.6 38.3 13.7 50.2 97.7 92.9 63.3 57.8 20.3 23.8 10.0 13.7 22.3 92.8 75.0 62 21 55 3 35.0 16.2 47.9 97.6 93.3 62.0 59. 24. 22. 12. 16. 22. ,3 .3 .6 .1 .2 ,1 - 124 -was hatch weight, H-3 week growth r a t e , 3-7 week growth r a t e and H-7 week growth r a t e . The second group t e s t e d was 1-week body weight, 1-3 week 2 growth r a t e , 3-7 week growth r a t e and 1-7 week growth r a t e . The r values f o r the s i n g l e t r a i t s r e l a t e d to 7-week body weight have been completely discussed p r e v i o u s l y as r e l a t e d to Table 58 and 59. They are presented i n Table 60 f o r the re a d e r s ' convenience i n r e f e r r i n g to the m u l t i p l e l i n e a r r e g r e s s i o n a n a l y s e s . The 3 t r a i t s ; 1-week body weight, 1-3 week growth r a t e and 3-7 week growth r a t e , explained on the average over 97 percent of the v a r i a t i o n i n 7-week body weight. This high percentage was i n good agreement w i t h Roberts (1965), S t a l e y et_ al _ . (1970) and Deland (1965). Using 1-week body weight and 1-7 week growth r a t e about 92 percent of the a s s o c i a t e d v a r i a t i o n was e x p l a i n e d . Using hatching weight and i t s a s s o c i a t e d growth r a t e s showed that l e s s v a r i a t i o n was explained f o r each of the above analogous s i t u a t i o n s about 92 and 70 p e r c e n t , r e s p e c t i v e l y . Therefore the use of hat c h i n g weight i n c a l c u l a t i n g growth r a t e value and subsequently using i t i n a m u l t i p l e l i n e a r r e g r e s s i o n analyses would not be as e f f e c t i v e as using 1-weekbody weight i n the aforementioned a n a l y s i s . I t was i n t e r e s t i n g to note that the obvious r e p l i c a t i o n e f f e c t shown i n many previous analyses was not apparent i n the m u l t i p l e l i n e a r r e g r e s s i o n analyses u s i n g 1-week body weight, 1-3 week growth r a t e and 3-7 week growth r a t e or was i t found when 1-7 week growth r a t e was used as the second independent v a r i a b l e . There were r e p l i c a t i o n d i f f e r e n c e s - 125 -noted when hatching weight was incorporated i n t o the growth r a t e a n a l y s i s . The e f f e c t of the e a r l y 1-3 week growth r a t e as i t i n f l u e n c e d the v a r i a t i o n of 7-week body weight was noted i n that on the average 1-week body weight and 1-3 week growth r a t e accounted f o r 62 percent of the v a r i a t i o n i n 7-week body weight. Where as 1-week body weight and 3-7 week growth r a t e showed a lower value of 54 percent. This s u b s t a n t i a l l y agrees w i t h the data of S t a l e y (1970) and Roberts (1965) and s t r o n g l y suggests t h a t the e a r l y growth periods have the most important i n f l u e n c e on the v a r i a t i o n of 7-week body weight. While the v a r i a b i l i t y of i n d i v i d u a l h a tching weight has been shown 2 to be c o n s i d e r a b l y i n f l u e n c e d by egg weight, r averaged 0.85 and 0.90 f o r both sexes i n r e p l i c a t i o n 1 and 2, r e s p e c t i v e l y (Table 5 3 ) , i t would be of i n t e r e s t to see i f any f u r t h e r v a r i a t i o n i n hatching weight could be ex-2 p l a i n e d by usi n g the embryonic d a t a . Table 61 shows the percent R f o r v a r i o u s embryonic data m u l t i p l e regressed on hatching weight. The data used f o r a n a l y s i s were the app r o p r i a t e mating c e l l means. On the average, over the 2 r e p l i c a t i o n s , 90 and 86 percent of the v a r i a t i o n i n hatching weight of males and females, r e s p e c t i v e l y , could be a s s o c i a t e d w i t h the v a r i a b i l i t y of pre-storage egg weight, 8 day embryo weight and a l l of the e a r l y growth r a t e p e r i o d s . When post-storage egg weight was s u b s t i t u t e d f o r pre-storage egg weight no a p p r e c i a b l e change was e v i d e n t . Using e i t h e r 8-16 or 8-18 day embryo growth r a t e and 8 day embryo weight w i t h pre- and TABLE 61. COEFFICIENTS OF DETERMINATION (100 x R2) OF HATCHING WEIGHTS MULTIPLE REGRESSED ON SELECTED TRAITS Selected t r a i t s CN xi 00 to CO •H CO >> >. >. cd cd Ha ^} CN <r cd o rH rH rH 1 1 o 1 CN 00 00 rH i-l CO CD >1 > i CO cn cd cd >N > i T3 i d cd cd T3 VO 00 rH rH VO 00 1 1 rH rH <t VO 1 1 rH r H 00 00 00 cd M ' O 4-1 W I <U r-l P-l OJ OO cd u o u CO I •u CD o CM Hatching Weight R e p l i c a t i o n 1 Male Female R e p l i c a t i o n 2 Male Female + + • + + + + + 91.2 83.9 89.8 88.5 + + + + + + + 91.1 . 83.8 89.4 88.6. + + + + + + 72.6 57.1.. 70.8 29.4 + + + 81.9 73.6 74.9 87.5 + + + 81.9 74.2 71.3 87.3 + + 30.3 45.9 11.6 16.1 + + 38.7 80.6 40.5 70.1 0.0 70.6 2.5 87.3 OV Pre-storage egg weight. Post-storage egg weight. - 127 -post-storage egg weight did not give any greater values than u s i n g pre-or post-storage egg weight a l o n e . Post-storage egg weight showed an 2 average R of 76 and 79 percent f o r males and females, r e s p e c t i v e l y . I t would appear that hatching weight i s , as i n d i c a t e d p r e v i o u s l y , almost com-p l e t e l y a s s o c i a t e d w i t h egg weight and the e f f e c t s of d i f f e r e n t embryo growth r a t e s were w e l l masked i n the hatched c h i c k . The analogous data to see what p r o p o r t i o n of the v a r i a t i o n i n 1-week body weight can be expl a i n e d by v a r i a t i o n i n embryonic growth i s shown i n Table 62. An average of 90 and 86 percent f o r males and females of 1-week body weight v a r i a t i o n could be explained by using 8 day embryo body weight and a l l embryonic growth p e r i o d s as w e l l as u s i n g post-storage egg weight and H - l week growth r a t e . By de-l e t i n g 8 day embryo weight the percentage value d i d not a p p r e c i a b l e change. Approximately 83 and 80 percent of the v a r i a t i o n i n 1-week body weight f o r male and female progeny, r e s p e c t i v e l y , could be accounted f o r u s i n g 8-16 day embryo growth r a t e along w i t h post-storage egg weight and H-l week growth r a t e . In f a c t the l a t t e r 2 t r a i t s by themselves on the average accounted f o r 80 percent of the v a r i a t i o n i n 1-week body weight. But e i t h e r t r a i t alone did not exceed 50 percent (and on the average f a r l e s s ) , w i t h i n any sex and r e p l i c a t i o n . While not shown i t should be apparent t h a t 100 percent of 1 week body weight v a r i a t i o n would be accounted f o r by u s i n g hatching weight 2 and H - l week growth r a t e . I t would seem that the high R v a l u e of 80 percent obtained u s i n g post-storage egg weight and hatching weight i s due to the c o r r e -l a t i o n between egg weight and hatching weight. Again the e f f e c t s of e a r l y TABLE 62. COEFFICIENTS OF DETERMINATION (100 x R ) OF 1-WEEK BODY WEIGHTS MULTIPLE REGRESSED ON SELECTED TRAITS Selec t e d t r a i t s 4J 0) Xi 00 00 to to CO to cd •H co >> >1 >. to to u CD >N cd cd cd cd >. o CN cd X) XI X) X) cd cd 4J rH X l X) X) CO 1 >. CN <r vO 00 I X cd o rH rH rH H VO 00 4J o X) rH I t 1 1 rH rH to 4J 1 o CN <r VO 1 1 o cd 00 00 rH rH rH rH 00 00 p-l 1-week body weight R e p l i c a t i o n 1 R e p l i c a t i o n 2 Male Female Male Female + + + + + + + + 87.7 88.1 91.9 85.1 + + + + 83.2 80.6 83.8 80.4 + + + + + + + 86.4 86.4 90.9 83.5 + + + 83.1 80.5 83.1 80.2 + + 81.9 79.0 80.9 80.2 + 41.4 21.3 1.5 14.9 + 16.2 40.2 46.9 22.9 Post-storage egg weight. Hatch-1 week growth r a t e . - 129 -embryonic growth are somewhat masked but some of t h e i r i n f l u e n c e s on 1 week body weight could be observed. H e r i t a b i l i t y Based on many p r i o r analyses arguments were made f o r s e p a r a t i n g the sexes f o r independent a n a l y s i s . The c o n s i s t e n t r e p l i c a t i o n e f f e c t w e l l documented throughout t h i s r e p o r t suggests t h a t f o r the h e r i t a b i l i t y e s t i -mates i t would be a d v i s a b l e to i n s p e c t these estimates f o r each r e p l i c a t i o n as w e l l as f o r each sex. In g e n e r a l , the h e r i t a b i l i t y estimates of embryo weights (Table 63) 2 based on the s i r e component of v a r i a n c e (h ) were very low ( l e s s than 0.01), f o r male and female progeny of both r e p l i c a t i o n s 1 and 2. R e c a l l t h a t ne-2 2 g a t i v e h estimates were s m a l l and rounded to zer o . The h based on the dam 2 2 ponent of v a r i a n c e (h^) was g e n e r a l l y much higher and on the average h^ f o r the male progeny ranged from 0.14 (18 day embryo weight) to 0.68 (8 day embryo w e i g h t ) . The s i m i l a r comparisons f o r the female progeny ranged from 0.15 (14 day embryo weight) to 0.53 (8 day embryo w e i g h t ) . This higher e s t i -2 2 mate f o r h , over t h a t of h would be expected i n that the comparable body d s weight a n a l y s e s , Table 7 and 9, showed a c o n s i s t e n t and s i g n i f i c a n t dam l i n e e f f e c t , and a c o n s i s t e n t n o n - s i g n i f i c a n t s i r e l i n e e f f e c t . In g e n e r a l , t h i s 2 type of d i f f e r e n c e i n the h estimates would i n d i c a t e a h i g h p r o p o r t i o n of maternal e f f e c t s can be a s s o c i a t e d w i t h embryo body weights. These maternal e f f e c t s were suggested as being a t t r i b u t a b l e to n u t r i t i o n a l environmental d i f f e r e n c e s w i t h i n the eggs of the d i f f e r e n t dam l i n e s . While t h i s argument TABLE 63. HERITABILITY ESTIMATES OF EMBRYO WEIGHTS, CALCULATIONS BASED ON SEPARATED SEX IN EACH REPLICATION R e p l i c a t i o n 1 R e p l i c a t i o n 2 Mean Days of in c u b a t i o n Male Female Male Female Male Female >2 -2 >2 N2 hD hs - 2 61 0.00 0.36 0.00 0.60 0.00 0.48 8 0.00 0.39 0.00 0.65 0.07 0.97 0.24 0.42 0.00 0.68 0.12 0.53 10 0.00 0.20 0.57 0.40 0.00 0.55 0.03 0.25 0.00 0.37 0.30 0.32 12 0.00 0.45 0.18 0.50 0.00 0.31 0.00 0.25 ' 0.00 0.38 0-08 0.37 14 0.01 0.18 0.00 0.00 0.00 0.72 0.00 0.37 0.00 0.45 0.00 0.15 16 0.03 0.14 0.00 0.48 0.10 0.24 0.00 0.04 0.06 0.19 0.00 0.26 18 0.00 0.00 0.00 0.36 0.01 0.30 0.05 0.46 0.00 0.14 0.00 0.41 6 day embryos not sexed. - 131 -cannot be t e s t e d i n t h i s t h e s i s i t would be a most i n t e r e s t i n g study i n developmental g e n e t i c s . 2 2 The h^ and h^ and t h e i r standard e r r o r s (S.E.) of the egg w e i g h t s , c h i c k growth r a t e s and c h i c k body weights c a l c u l a t e d f o r each sex and r e p l i c a t i o n are presented f o r the r e a d e r s ' i n s p e c t i o n i n Table 64 ( r e p l i c a -t i o n 1) and 65 ( r e p l i c a t i o n 2 ) . The averaged r e p l i c a t e d values f o r male 2 and female progeny are shown i n Table 66. A l l negative v a l u e s of h estimates found i n t h i s study were assumed to be z e r o , t h e r e f o r e no nega-t i v e values appear i n the aforementioned t a b l e s . 2 A number of previous i n v e s t i g a t o r s have made estimates of h of egg weight. The summary of these by Shoffner and Sloan (1948) as c i t e d by Lerner and Cruden (1951) i n d i c a t e d t h a t the range of estimates was from 0.46 2 to 0.84. I n the present study, the average h estimates of pre- and post-2 2 storage egg w e i g h t s , (h + h^)/2, were found to be 0.42 f o r both male and 2 female progeny. The h g averaged f o r the 2 r e p l i c a t i o n s was 0.07. T h i s was c o n s i s t e n t f o r the male and female progeny. T h i s estimate was much lower than those reported i n the l i t e r a t u r e . The low estimates might be due, at l e a s t i n p a r t , to the f a c t t h a t the 4 l i n e s of chickens s t u d i e d are not completely homozygous. As a consequence the a d d i t i v e g e n e t i c v a r i a n c e w i t h -i n the l i n e would be minimized w i t h i n the s i r e l i n e component of v a r i a n c e 2 2 which would g i v e a lower estimate of h . The very h i g h h^ estimates of pre-and post-storage egg weights (0.84) presumably r e f l e c t e d a maternal e f f e c t on egg w e i g h t s . The estimate of the maternal e f f e c t , computed as the dam TABLE 64. HERITABILITY ESTIMATES (h ) AND STANDARD ERROR (S.E.) OF EGG WEIGHTS, CHICK GROWTH RATES AND BODY WEIGHTS (REPLICATION 1) Male Female T r a i t h 2s (S.E.) h^ (S.E.) (S.E.) h j (S.E.) Pre-storage egg weight 0 10 (0.08) 1. 00 (0.62) 0. 02 (0.00) 1. 00 (0.62) Post-storage egg weight 0 10 (0.08) 1. 00 (0.62) 0. 02 (0.00) 1. 00 (0.62) Hatch-1 week G.R.1 0 00 (0.00) 0. 00 (0.00) 0. 06 (0.05) 0. 07 (0.06) 1-2 week G.R. 0 12 (0.10) 0. 17 (0.14) 0. 09 (0.08) 0. 08 (0.08) 2-3 week G.R. 0 21 (0.17) 0. 37 (0.28) 0. 48 (0.36) 0. 46 (0.34) 3-4 week G.R. 0 31 (0.24) 0. 29 (0.23) 0. 43 (0.32) 0. 42 (0.32) 4-5 week G.R. 0 37 (0.28) 0. 27 (0.21) 0. 44 (0.33) 0. 34 (0.26) 5-6 week G.R. 0 06 (0.05) 0. 17 (0.14) 0. 40 (0.30) 0. 18 (0.15) 6-7 week G.R. 0 24 (0.20) o; 21 (0.17) 0. 47 (0.35) 0. 41 (0.31) 1-3 week G.R. 0 24 (0.20) 0. 37 (0.28) 0. 41 (0.31) 0. 39 (0.29) 3-7 week G.R. 0 49 (0.36) o. 52 (0.38) o. 99 (0.62) 0. 78 (0.52) 1-7 week G.R. 0 55 (0.40) o. 67 (0.46) o. 97 (0.61) 0. 84 (0.55) Hatch-3 week G.R. 0 20 (0.16) 0. 57 (0.44) 0. 07 (0.06) 0. 25 (0.20) Hatch-7 week G.R. 0 81 (0.54) l . 00 (0.62) 1. 00 (0.62) 1. 00 (0.62) Hatching weight 0 25 (0.20) 0. 99 (0.62) 0. 02 (0.00) 0. 74 (0.50) 1-week body weight 0 09 (0.08) 0. 09 (0.08) 0. 26 (0.21) 0. 18 (0.15) 2-week body weight 0 01 (0.00) 0. 00 (0.00) 0. 19 (0.16) 0. 08 (0.08) 3-week body weight 0 00 (0.00) 0. 00 (0.00) 0. 05 (0.04) 0. 03 (0.00) 4-week body weight 0 03 (0.04) 0. 12 (0.10) 0. 05 (0.04) 0. 08 (0.08) 5-week body weight 0 10 (0.08) 0. 31 (0.24) 0. 09 (0.08) 0. 25 (0.20) 6-week body weight 0 17 (0.14) 0. 45 (0.33) 0. 23 (0.19) 0. 39 (0.29) 7-week body weight d 29 (0.23) 0. 61 (0.43) 0. 41 (0.31) 0. 57 (0,41) Growth r a t e . TABLE 65. HERITABILITY ESTIMATES (h ) AND STANDARD ERROR (S.E.) OF EGG WEIGHTS, CHICK GROWTH RATES AND BODY WEIGHTS ( R e p l i c a t i o n 2) Male Female T r a i t (S .E.) (S.E.) h s (S.E.) -2 (S .E.) Pre-storage egg weight 0 .04 (0 .04) 0 .40 (0 .30) 0 .12 (0 10) 0 .69 (0 .47) Post-storage egg weight Hatch-1 week G.R. 0 .04 (0 .04) 0 .38 (0 .29) 0 .12 (0 10) 0 .68 (0 .47) 0 .00 (0 .00) 0 .09 (0 .08) 0 .01 (0 .00) 0 .08 (0 .08) 1-2 week G.R. 0 .13 (0 .10) 0 00 (0 .00) 0 .20 (0 16) ]0 .00 (0 .00) 2-3 week G.R. 0 .20 (0 .16) 0 .11 (0 .09) 0 .19 (0 16) 0 .16 (0 .13) 3-4 week G.R. 0 .12 (0 .10) 0 16 (0 • 13) 0 .30 (0 22) 0 .23 (0 .19) 4-5 week G.R. 0 .11 (0 .09) 0 16 (0 .13) 0 .03 (0 04) 0 .11 (0 .09) 5-6 week G.R. 0 .05 (0 .05) 0 .17 (0 .14) 0 .24 (0 20) 0 .18 (0 • 15) 6-7 week G.R. 0 .07 (0 .06) 0 00 (0 .00) 0 .00 (0 00) 0 .01 (0 .00) 1-3 week G.R. 0 .30 (0 .24) 0 .08 (0 .08) 0 .29 (0 22) 0 .10 (0 .08) 3-7 week G.R. 0 .21 (0 .16) 0 12 (0 .10) 0 .40 (0 30) 0 .38 (0 .29) 1-7 week G.R. 0 .41 (0 .31) 0 .20 (0 .16) 0 .52 (0 38) 0 .43 (0 .32) Hatch-3 week G.R. 0 .15 (0 .13) 0 26 (0 .21) 0 .35 (0 25) 0 .35 (0 • 27) Hatch-7 week G.R. 0 .50 (0 .37) 0 42 (0 .32) 0 .65 (0 45) 0 .73 (0 .49) Hatching weight 0 07 (0 .06) 0 29 (0 .23) 0 .12 (0 10) 0 .54 (0 38) 1-week body weight 0 00 (0 .00) 0 00 ' (0 .00) 0 .05 ' (0 04) 0 .01 (0 00) 2-week body weight 0 00 (0 .00) 0 00 (0 .00) 0 .12 (0 10) 0 .00 (0 00) 3-week body weight 0 00 (0 .00) 0 06 (0 .05) 0 .21 (0 16) 0 .09 (0 .08) 4-week body weight 0 05 (0 .05) 0 22 (0 .18) 0 .28 (0 22) 0 .25 (0 20) 5-week body weight 0 15 (0 .13) 0 37 (0 .28) 0 .29 (Q 22) 0 .39 (0 30) 6-week body weight 0 28 (0 .22) 0 55 (0 .40) 0 .38 (0 28) 0 .55 (0 40) 7-week body weight 0 34 (0 .26) 0 43 (0 .32) 0 .41 (0 30) 0 .54 (0 39) Growth r a t e . - 134 -TABLE 66. HERITABILITY ESTIMATES OF EGG WEIGHT, GHICK GROWTH RATES AND BODY WEIGHTS, CALCULATIONS BASED ON THE AVERAGES ACROSS REPLICATIONS Male Female 2 2 2 2 T r a i t h g h D h s h D P r e - s t o r a g e egg w e i g h t 0.07 0. 70 0.07 0.84 P o s t - s t o r a g e egg w e i g h t 0.07 0.69 0.07 0.84 H a t c h i n g w e i g h t 0.16 0.64 0.07 0.64 1 Week w e i g h t 0.01 0.02 0.15 0.09 2 Week w e i g h t 0.00 0.00 0.15 0.03 3 Week w e i g h t 0.00 0.03 0.13 0.06 4 Week w e i g h t 0.04 0.17 0.16 0.16 5 Week w e i g h t 0.12 0.34 0.19 0.32 6 Week w e i g h t 0.22 0.50 0.30 0.47 7 Week w e i g h t 0.31 0.52 0.41 0.55 H - l Week growth r a t e 0.00 0.02 0.03 0.07 1-2 Week growth r a t e 0.12 0.08 0.14 0.04 2-3 Week growth r a t e 0.20 0.24 0.33 0.31 3-4 Week growth r a t e 0.21 .0.22 0.36 0.32 4-5 Week growth r a t e 0.24 0.21 0.23 0.22 5-6 Week growth r a t e 0.05 0.17 0.32 0.18 6-7 Week growth r a t e 0.15 0.10 0.22 0.21 1-3 Week growth r a t e 0.27 0.22 0.35 0.24 3-7 Week growth r a t e 0.35 0.32 0.69 0.58 1-7 Week growth r a t e 0.48 0.43 0.74 0.63 - 135 -minus the s i r e variance component expressed as a f r a c t i o n of the sum of the variance components ( a f t e r Mover, C o l l i n s and Skoglund, 1962) was on the average, 0.205. 2 The averaged body weight h estimates across r e p l i c a t i o n s (Table 66 2 showed that f o r hatching weight the h^ (0.64) f o r both sexes was much higher 2 than h (males: 0.06 and females: 0.07). The large maternal e f f e c t (that of s egg weight) was reduced considerably, and i t may have been minimum at 1 week 2 2 of age: h, = 0.02 and 0.09: h = 0.01 and 0.15, males and females respec-d s 2 2 t i v e l y . The body weight h estimates at 2 weeks of age h g = 0.00 and 0.15; 2 h, = 0.02 and 0.09, males and females r e s p e c t i v e l y , showed no evidence of d a maternal e f f e c t . 2 The reduction i n the h, estimates f o r hatch, 1 and 2 weeks of age d follows that noted i n the c o r r e l a t i o n analyses between egg weight and chick weight (Table 53). I t would appear that t h i s strong r e l a t i o n s h i p between 2 egg weight and early chick weight influenced the h analyses at l e a s t at hatch and at 1 week of age. 2 It was of extreme i n t e r e s t to note the increasing body weight h, d estimate s t a r t i n g at 4 weeks of age for both sexes. Considering t h i s i n -2 creasing value was always l a r g e r than the h estimates, which also increased s during the following weeks, i t i n d i c a t e d that a new e f f e c t was being evalu-ated iri the dam source of v a r i a t i o n , e s p e c i a l l y , since the maternal e f f e c t 2 of egg weight had been eliminated by 3 weeks of age. The increase of h^ estimates for body weight from 4 to 8 weeks of age was i n a good agreement 2 with those reported by Moyer et a l . (1962), but not for the h^ estimates for the same corresponding t r a i t s . There does not seem to be any - 136 -v a l i d reason f o r a new maternal e f f e c t to be i n i t i a t e d at 4 weeks of age. Apparently other f a c t o r s must be considered. Sex l i n k a g e a s s o c i a t e d 2 2 w i t h d i f f e r e n c e s between h and h., which should respond d i f f e r e n t l y w i t h i n s d each sex (Jaap et_ a l . , 1963) would not seem to be the answer, s i n c e the s e x - l i n k a g e e f f e c t should have e x i s t e d c o n s i s t e n t l y from hatch to 3 weeks of age, which again was not the case. This was c o n t r a r y to the d i s c u s s i o n of Thomas et a l . (1958). 2 2 The body weight h estimates f o r each sex showed t h a t h^ f o r both sexes were q u i t e s i m i l a r throughout a l l weekly e s t i m a t e s . In c o n t r a s t the 2 h g f o r the male progeny was c o n s i s t e n t l y lower f o r the e n t i r e p e r i o d of the t e s t , an approximate d i f f e r e n c e of 0.10 i n favour of the female progeny. The reasons f o r such a dLfference was not apparent but d e f i n i t e l y i n d i c a t e d that the a n a l y t i c a l procedures i n se p a r a t i n g the sexes was worthwhile. T h i s sex 2 d i f f e r e n c e i n body weight h estimates has been noted by Moyer, e_t a l . (1962) and Thomas et a l . (1958). 2 The r e p l i c a t e d average of the h estimates f o r weekly growth r a t e s , 2 a l s o l i s t e d i n Table 66, showed that the h estimate of H - l weekly growth 2 2 r a t e f o r both sexes was very low: h = 0.00 and 0.03: h , = 0.02 and 0.07 s d f o r males and females, r e s p e c t i v e l y . These low estimates are not unexpected s i n c e the H -l week growth r a t e had been shown to be n e a r l y completely de-pendent upon the egg s i z e (Table 53).As a consequence t h i s p e r i o d of growth was a recovery phase from the egg environment (Bray and I t o n , 1962; Deland, - 137 -1965) and i n a d d i t i o n i t would not be expected to demonstrate the c h i c k genetic d i f f e r e n c e s . As the data i n d i c a t e s these genetic d i f f e r e n c e s appear to be w e l l masked during the hatching phase. 2 The h estimates f o r the 1-2 week growth r a t e s were higher than the H-l v a l u e s . R e c a l l i n g that the recovery phase was a l s o demonstrated to e x i s t , at a lower l e v e l , f o r t h i s growth p e r i o d (Table 5 8 ) , the i n c r e a s e d 2 h estimates f o l l o w s that of the b i o l o g i c a l environment t h a t e x i s t e d . I t was of extreme i n t e r e s t t o note that f o r the f i r s t 2 growth 2 periods as w e l l as f o r a l l of the subsequent growth per i o d s the h estimates 2 2 f o r h and h , w i t h i n both sexes d i d not show any evidence of a maternal s d e f f e c t . This of course was i n d i r e c t c o n t r a s t to the body weight data where the evidence of a maternal e f f e c t at h a t c h i n g , which decreased to a minimum at 3 weeks of age, and subsequently increased t i l l 7 weeks of age, was q u i t e s t r o n g . T h i s may r e f l e c t one c o n s i d e r a b l e advantage of growth r a t e a n a l y s i s . I f a strong maternal e f f e c t i n f l u e n c e d the d a t a , t h i s e f f e c t would be r e -f l e c t e d i n the weekly body weights. R e c a l l i n g that body weight v a r i a n c e i n -creased w i t h age (Table 25) a f a c t which has been demonstrated many ti m e s , i n the l i a t e r a t u r e , the aforementioned e f f e c t would be expected to i n c r e a s e i n p r o p o r t i o n to the body weight v a r i a n c e . In other words i t should be magnified as the b i r d s get o l d e r . The growth r a t e c a l c u l a t i o n however was based on a r a t i o of body weights f o r 2 periods of time f o r the same i n d i v i d u a l . T h is r a t i o apparently e l i m i n a t e d any such e f f e c t that was c o n s i s t e n t w i t h i n - 138 -2 an i n d i v i d u a l . With the removal of these e f f e c t s the h estimate should s 2 approximate very c l o s e l y the h^ values w i t h i n each sex. T h i s of course was 2 r e f l e c t e d i n the h estimates obtained f o r weekly growth r a t e s of t h i s study. 2 The h estimates f o r both sexes f o r the 2-3 week growth r a t e and t h e r e a f t e r were f a i r l y c o n s i s t e n t , e s p e c i a l l y f o r the female progeny. The 2 2 male progeny may have shown a s l i g h t d e c l i n e i n both h g and h^ i n the l a t e r 2 growth periods but no such change was apparent i n the female progeny. In 2 2 a d d i t i o n these may have been s l i g h t l y higher estimates f o r h g and h^ i n the female progeny, but again t h i s was not c o n s i s t e n t . Such sex d i f f e r e n c e s 2 were evident when the h estimates f o r the 1-3, 3-7 as w e l l as the 1-7 week growth r a t e s were compared. 2 The male progeny f o r the 1-3 week growth r a t e had h = 0.27 and 2 2 h^ = 0.22 w h i l e these h estimates were s i m i l a r the comparable female progeny 2 2 had h .= 0.35 and h , = 0.24. While admittedly the sexes at t h i s stage may s d not be too d i f f e r e n t the same estimates f o r the 3-7 week growth r a t e showed 2 2 2 2 male h =0.35 and h , = 0.32 w h i l e the female h =0.69 and h , = 0.58. s d s d Cons i d e r i n g the s i z e of the p o p u l a t i o n studied i t would be reasonable to 2 assume that t r u e d i f f e r e n c e s i n the h estimates do e x i s t at l e a s t i n the l a t t e r growth stages. 2 The same d i f f e r e n c e was r e f l e c t e d when the 1-7 week growth r a t e h 2 2 estimates were compared. The male progeny showed h g =0.48 and h^ = 0.43 2 2 and the female progeny showed h g = 0.74 and h^ = 0.63. I t should be - 139 -poi n t e d out that the 3 p e r i o d s , 1-3, 3-7 and 1-7 week growth r a t e s showed 2 c o n s i s t e n t l y an i n c r e a s i n g value f o r the h esti m a t e s . For example i n the 2 male progeny the values were h^ = 0.27, 0.35 and 0.48 f o r the 3 p e r i o d s , 2 r e s p e c t i v e l y . In s p i t e of the notable i n c r e a s e i n the h estimates 2 2 e s p e c i a l l y consider the degree of u n i f o r m i t y of h^ and h^ w i t h i n the male 2 progeny. While the aforementioned 3 growth periods showed i n c r e a s i n g h estimates an e x p l a n a t i o n of t h i s e f f e c t was not evident i n the d a t a , w i t h the exception that the 1-2 week growth r a t e has been noted to be w i t h i n the 2 r e c o v e r i n g phase a f t e r h a t c h i n g , and as a consequence the h estimate was reduced. This may be the unique e x p l a n a t i o n f o r the lower 1-3 week growth 2 2 r a t e h e s t i m a t e s . This of course would mean that 1-7 week growth r a t e h estimate which was much l a r g e r could have masked the e a r l y 1-2 week e f f e c t . U n f o r t u n a t e l y t h i s e x p l a n a t i o n cannot be t e s t e d w i t h the present d a t a . 2 While there was no evidence of a sex l i n k a g e e f f e c t found i n the h 2 data of the male progeny i t was i n t e r e s t i n g to note that f o r the h e s t i -2 mates f o r t h i s 1-3, 3-7 and 1-7 week growth r a t e s of the female progeny h g 2 was c o n s i s t e n t l y l a r g e r than h^: on the average a d i f f e r e n c e of 0.10 i n 2 favour of h^. In female progreny where the female i s the heterogametic sex 1/2 of the va r i a n c e of the s e x - l i n k e d genes i s found i n the s i r e component of v a r i a n c e (Becker, 1967). The dam component does not c o n t a i n any sex 2 2 l i n k a g e e f f e c t . Therefore when the h exceeds that of the h . i n female s d progeny i t would be considered an i n d i c a t i o n of the In f l u e n c e on the t r a i t 2 2 of sex l i n k a g e . The h g and h^ of the male progeny r e f l e c t 1/4 and 1/2 of - 140 -the v a r i a t i o n of s e x - l i n k e d e f f e c t s , r e s p e c t i v e l y . There was no i n d i c a -t i o n of sex l i n k a g e i n the growth r a t e t r a i t s of the males, however, t h i s p o s s i b l e e f f e c t cannot be overlooked i n that the female progeny showed d e f i n i t e i n d i c a t i o n that such an e f f e c t e x i s t e d . 2 I n g e n e r a l , however, the e n t i r e growth r a t e h estimate data showed a major source of a d d i t i v e genetic v a r i a t i o n i s present i n p o u l t r y popula-t i o n s , which h e r e t o f o r e , has never been d i r e c t l y e x p l o i t e d i n improving the body weight of the young c h i c k e n s . SUMMARY AND CONCLUSIONS A t o t a l of 7,472 progeny from 4 l i n e s of chickens, a Black Austra-lorp (BA), a New Hampshire (NH) and 2 Leghorn l i n e s (UBC and MH), t h e i r crosses and t h e i r r e c i p r o c a l s were assessed f o r t h e i r pre- and post-hatching body weights, t h e i r pre- and post-hatching growth rates and t h e i r associated egg weights. i The i n t e r r e l a t i o n s h i p s of these t r a i t s as they influenced growth and 7-week body weight were evaluated. The e f f e c t of these r e l a t i o n s h i p s were j o i n t l y considered as they influenced the genetic v a r i a t i o n and sub-2 sequent estimates of the h e r i t a b i l i t y estimates (h ) of these t r a i t s . The following conclusions were reached based on the data: 1. Sex diff e r e n c e s i n embryo body weights were found at 8 to 18 days of embryo development. This d i f f e r e n c e could be a t t r i b u t a b l e to a growth rate d i f f e r e n c e between the sexes f o r the 6-8 day embryo growth rate, and i t was suggested that t h i s d i f f e r e n c e occurred much e a r l i e r i n embryonic growth. 2. A maternal i n f l u e n c e , not re l a t e d to egg weight at l e a s t u n t i l 16 days age, on embryo weight for both sexes was found at 6 to 18 days of incu-bation. 3. A l l s i r e x dam i n t e r a c t i o n s that were co n s i s t e n t l y s i g n i f i c a n t f o r a l l analyses of variance of body weight from hatch to 7 weeks of age were not i n evidence when the data was analysed based on growth rate (b) using the power function (Y = a t b ) . This suggests that growth rate - 141 -- 142 -shows a l i n e a r r e l a t i o n s h i p e x i s t i n g between the s i r e s and dams, and that bod}' weight shows an i n t e r a c t i o n that i s not g e n e t i c a l l y determined but r a t h e r an a r t i f a c t of the n o n - l i n e a r i t y of body weight per se. 4. The value of the power f u n c t i o n i n transforming the data was again demonstrated i n that the n o n s i g n i f i c a n t s i r e and dam l i n e e f f e c t s a s s o c i a t e d w i t h a l l body weight analyses were c o n s i s t e n t l y s i g n i f i c a n t throughout the growth r a t e analyses f o r each sex. 5. The environmental i n f l u e n c e of egg weight, reported i n the l i t e r a t u r e , was s t r o n g l y demonstrated i n th a t on the average 76 percent of the v a r i a t i o n i n hatching weight could be a s s o c i a t e d w i t h the v a r i a b i l i t y of egg weight. 6. The r e d u c t i o n of t h i s i n f l u e n c e (the recovery phase) was demonstrated i n the H - l week growth r a t e as i t showed the strongest a s s o c i a t i o n w i t h egg weight. 7. The adverse environmental e f f e c t of ha t c h i n g was d e f i n i t e l y e s t a b l i s h e d i n that i t took 2 weeks of growth a f t e r hatching f o r the chicken body weights to a t t a i n the same l e v e l of a s s o c i a t i o n w i t h 7-week body weight t h a t was p r e v i o u s l y shown i n the body weights of the 18 day embryo. 8. The r e l a t i v e independence of the 2 t r a i t s (body weight and growth r a t e ) was e s t a b l i s h e d , however, when an adverse environment i n f l u e n c e d growth, t h i s independence was modified f o r that weeks growth r a t e mea-surement . - 143 -9. M u l t i p l e r e g r e s s i o n a n a l y s i s showed that 1 week body weight and any subsequent growth periods accounted f o r more v a r i a t i o n i n 1-week body weight than d i d the use of hatching weight, and i t s subsequent growth p e r i o d s , because hatching weight was p r i m a r i l y r e l a t e d to.egg s i z e and the growth f o r H-l week of age was b a s i c a l l y a recovery p e r i o d . 10. A c o n s i s t e n t i n f l u e n c e of r e p l i c a t i o n was evident throughout the study, and aside from some unique p e r i o d s of growth was b a s i c a l l y a t t r i b u t a b l e to egg s i z e d i f f e r e n c e s between the two r e p l i c a t i o n s , ( 5 5 . 3 and 60.3 grams). This was due to a 7-week d i f f e r e n c e i n the age of the dams. 11. The strong maternal e f f e c t noted i n the embryo body weight analyses was 2 r e a f f i r m e d w i t h the h estimate f o r each sex and r e p l i c a t i o n i n that 2 2 h g was very low and h^ r e l a t i v e l y l a r g e . 12. The maternal e f f e c t of egg weight on the body weight of the hatched 2 c h i c k s was demonstrable i n the h estimates only u n t i l 2 weeks of age, and i t was n i l at 3 weeks of age. 2 13. A new maternal e f f e c t on body weight noted i n the h estimates could be measured s t a r t i n g at 4 weeks of age, the reason f o r t h i s e f f e c t could not be a t t r i b u t a b l e to any know source of v a r i a t i o n . 2 2 14. The h g and h^ f o r weekly growth r a t e e q u a l l y r e f l e c t e d the adverse e f f e c t of egg weight on the H - l and 1-2 week growth r a t e . T h i s was considered to be analogous to the aforementioned maternal i n f l u e n c e on body weight. - 144 -15. The h and h , of growth r a t e estimates f o r both sexes d i d not demon-s d s t r a t e any change s t a r t i n g at 4 weeks of age or t h e r e a f t e r that could 2 be a s s o c i a t e d w i t h the noted new -maternal e f f e c t f i r s t seen i n the h estimate of 4 week body weight, t h e r e f o r e , i t was suggested that due 2 to the method of c a l c u l a t i o n of weekly growth r a t e the h estimate of th a t t r a i t would be expected to be r e l a t i v e l y constant s t a r t i n g at 2 weeks of age. 2 16. The h estimates obtained f o r a l l weekly growth r a t e s as w e l l as the 1-3, 3-7 and 1-7 week growth r a t e s s t r o n g l y i n d i c a t e d a good source of a d d i t i v e genetic v a r i a n c e was a v a i l a b l e i n p o u l t r y p o p u l a t i o n s h e r e t o -f o r e not u t i l i z e d d i r e c t l y i n body weight s e l e c t i o n programs. BIBLIOGRAPHY Becker, W.A., 1967. 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A s s o c i a t i o n of egg weight and c h i c k weight. P o u l t r y S c i . 36: 1149. Roberts, C.W., 1964. E s t i m a t i o n of e a r l y growth r a t e i n the c h i c k e n . P o u l t r y S c i . 43: 238-252. Roberts, C.W., 1965. One week body weight and bi-weekly e a r l y growth r a t e as r e l a t e d to 7-week body weight i n the c h i c k e n . P o u l t r y S c i . 44: 947-952. - 149 -Schmidt, J . , 1919. D i a l l e l c r o s s i n g s w i t h t r o u t . J . G e n e t i c s , 9: 61-67. Schmidt, J . , 1922. D i a l l e l c r o s s i n g s w i t h the domestic f o w l . J . G e n e t i c s , 12: 241-245. S c h n e t z l e r , E.E., 1936. I n h e r i t a n c e of r a t e of growth i n Barred Plymouth Rocks. P o u l t r y S c i . 15: 369-376. S i e g e l , P.B., 1962. S e l e c t i o n f o r body weight at 8 weeks of age. P o u l t r y S c i . 41: 954-962. Skoglund, W.C., K.C. Seegar and A.T. R i n g r e s s , 1952. 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The h e r i t a b i l i t y of body weight g a i n , feed consumption and feed con-v e r s i o n i n b r o i l e r s . P o u l t r y S c i . 37: 862-869. T i n d e l , D. and D.R. M o r r i s , 1964. The e f f e c t s of egg weight on subsequent b r o i l e r performance. P o u l t r y S c i . 43:534-539. Upp, C.W., 1928. Egg weight, day o l d c h i c k weight and r a t e of growth i n Si n g l e Comb Rhode I s l a n d Red c h i c k s . P o u l t r y S c i . 7: 151-155. Waters, N.F. and J.H. Bywaters, 1943. A study of body weights i n nine d i f f e r e n t s t r a i n s of White Leghorns. P o u l t r y S c i . 22: 178-187. W i l e y , W.H., 1950a. The i n f l u e n c e of egg weight on the pre-hatching and post-hatching growth r a t e i n the f o w l . I . Egg weight-embryonic development r a t i o s . P o u l t r y S c i . 29: 570-574. - 150 -W i l e y , W.H., 1950b. The i n f l u e n c e of egg weight on the pre-hatching and post-hatching growth r a t e i n the f o w l . II. Egg weight-chick weight r a t i o s . P o u l t r y S c i . 29: 595-604. - 151 -APPENDIX LIST OF APPENDIX TABLES Appendix Table Page 1 Number of Embryos of Males and Females i n Each R e p l i c a t i o n and Genotype f o r Every Day Weighed 153 2 Mean Embryo Growth. Rates Within Each Sex and Genotype for Varying Growth Periods Across R e p l i c a t i o n s 155 3 Mean Embryo Growth Rates by Sire and Dam Line of Males and Females f o r Varying Growth Periods Across R e p l i c a -tions 157 4 Number of Post-hatch Progeny f o r Each Sex, Genotype and R e p l i c a t i o n 158 - 152 -APPENDIX TABLE 1. NUMBER OF EMBRYOS OF MALES (M) AND FEMALES (F) IN EACH REPLICATION (R) AND GENOTYPE FOR EVERY DAY WEIGHED S i r e l i n e BA MH NH UBC T o t a l D a m R l 2 1 2 1 2 1 2 1 2 l i n e Day M F M F M F M F M F M F M F M F M F M F 6 19 17 23 16 21 17 19 21 82 71 8 17 6 5 15 14 7 11 6 11 13 12 7 12 7 8 14 54 33 36 42 10 9 14 9 9 14 5 10 12 14 7 17 4 10 12 14 7 47 38 50 32 12 8 13 7 12 14 9 12 8 9 10 7 10 9 10 9 13 40 42 35 43 14 10 10 14 7 5 14 6 9 11 13 9 10 13 9 13 11 39 46 42 37 16 8 9 9 9 10 14 13 6 12 9 9 11 8 9 11 8 38 41 42 34 18 14 8 8 5 12 11 10 7 13 6 6 8 9 12 9 11 48 37 33 31 6 19 20 15 15 20 20 22 21 76 76 8 11 8 13 8 9 8 15 8 10 5 13 7 10 8 21 5 40 29 62 28 10 8 5 9 17 7 10 14 10 5 10 8 12 14 6 18 8 34 31 49 47 12 10 8 13 7 7 8 9 11 8 7 15 6 12 6 9 10 37 29 46 34 14 7 6 9 15 8 9 10 11 7 10 7 12 11 9 9 17 33 34 35 55 16 2 11 11 8 6 10 8 8 8 9 5 10 8 8 13 9 24 • 38 37 35 18 9 8 12 9 4 10 7 10 5 9 5 10 10 8 9 14 28 35 33 43 Continued APPENDIX TABLE 1. (Continued) S i r e l i n e BA MH NH UBC T o t a l Dam R 1 2 1 2 1 2 1 2 1 2 l i n e Day M F M F M F M F M F M F M F M F M F M F 6 20 24 21 17 22 22 24 18 87 81 8 9 13 12 13 10 15 12 6 10 13 12 10 15 6 12 6 44 47 48 35 10 12 9 16 9 10 11 13 10 14 8 17 7 9 11 9 8 45 39 55 34 12 9 14 11 11 11 12 12 9 12 11 18 6 15 8 11 6 47 45 52 32 14 8 10 15 9 13 7 15 9 9 12 10 9 10 11 17 5 40 40 57 32 16 14 6 7 14 12 7 9 12 10 11 13 9 10 13 10 7 46 37 39 42 18 11 7 7 15 14 9 10 8 5 10 13 9 14 9 12 4 44 35 42 36 6 19 25 20 25 20 19 16 21 75 90 8 10 9 16 10 8 13 9 14 8 9 12 11 8 8 12 7 34 39 49 42 10 12 6 14 6 12 11 11 10 12 6 14 9 11 6 14 2 47 29 53 27 12 11 8 7 17 14 6 6 15 7 9 10 10 8 7 8 10 40 30 31 52 14 9 8 16 11 8 11 8 10 10 11 11 10 13 10 6 13 40 40 41 44 16 7 8 10 14 16 5 14 10 11 9 10 9 15 4 11 9 49 26 45 42 18 7 9 13 5 9 15 11 11 16 7 11 11 8 9 14 8 40 40 49 35 77* 86* 79* 73* 83* 78* 81* 81* 320* 318* 232 213 263 255 247 237 255 230 237 224 264 217 262 206 279 212 978 880 1061 914 T o t a l no. of 6 day embryos - 155 -APPENDIX TABLE 2. MEAN EMBRYO GROWTH RATES WITHIN EACH SEX AND GENOTYPE FOR VARYING GROWTH PERIODS ACROSS REPLICATIONS S i r e l i n e BA MH NH UBC Dam l i n e Day Male Female Male Female Male Female Male Female 6-10 6-12 6-14 BA 6-16 6-18 8-12 8-14 8-16 6-10 6-12 6-14 MH 6-16 6-18 8-12 8-14 8-16 6-10 6-12 6-14 NH 6-16 6-18 8-12 8-14 8-16 6-10 6-12 6-14 UBC 6-16 6-18 8-12 8-14 8-16 3.80 3.68 3.94 3.86 3.98 3.98 3.92 3.92 3.74 3.70 3.72 3.61 3.84 3.86 3.79 3.80 3.92 3.87 4.08 4.00 4.10 4.16 4.00 3.99 3.89 3.84 3.82 3.64 3.95 3.97 3.86 3.80 3.92 3.83 3.98 3.83 4.06 4.04 4.00 4.01 3.84 3.80 3.70 3.59 3.89 3.96 3.86 3.94 3.80 3.77 3.91 3.84 4.04 3.98 3.97 3.90 3.82 3.82 3.62 3.62 3.90 3.88 3.84 3.80 3.78 3.84 3.92 3.84 4.02 3.99 3.87 3.84 3.72 3.70 3.72 3.77 3.92 3.99 3.76 3.82 3.98 3.98 3.99 4.01 4.16 4.06 4.05 4.02 3.82 3.80 3.72 3.88 4.02 3.98 3.93 3.95 3.92 3.74 4.04 3.94 4.06 4.11 3.99 4.03 3.85 3.88 3.82 3.82 3.93 4.09 3.86 4.00 4.06 3.96 3.97 3.90 4.06 4.04 3.92 3.99 3.81 3.82 3.58 3.58 3.84 3.87 3.72 3.86 3.66 3.61 3.97 3.88 3.92 3.86 3.86 3.78 3.72 3.70 4.00 3.90 3.92 3.88 3.84 3.77 3.92 3.96 4.05 4.02 4.09 4.12 4.00 3.97 3.91 3.84 3.86 4.02 3.98 4.16 3.89 3.96 3.86 3.88 3.94 3.94 4.10 4.10 3.98 3.98 3.88 3.84 3.74 3.84 4.01 4.08 3.88 3.94 4.06 3.98 4.04 4.00 4.16 4.12 4.02 4.00 3.86 3.88 3.76 '3.68 4.02 3.95 3.87 3.84 3.68 3.60 3.74 3.74 3.96 3.90 3.84 3.82 3.72 3.72 3.62 3.70 3.96 3.92 3.82 3.82 3.96 3.90 4.05 3.94 4.10 4.14 4.01 4.02 3.86 3.85 3.78 3.62 3.94 3.98 3.87 3.88 3.93 3.82 3.93 3.96 4.08 4.04 3.96 3.96 3.77 3.80 3.68 3.82 3.98 3.96 3.84 3.88 3.92 3.89 4.00 3.88 4.04 4.04 3.94 4.00 3.80 3.85 3.80 3.76 3.92 4.02 3.82 3.96 C o n t i n u e d - 156 -APPENDIX TABLE 2. ( C o n t i n u e d ) S i r e l i n e BA MH NH UBC Dam l i n e Day Male Female Male Female Male Female Male Female 8-18 10-14 10-16 BA 10-18 12-16 12-18 14-18 8-18 10-14 10-16 MH 10-18 12-16 12-18 14-18 8-18 10-14 10-16 NH 10-18 12-16 12-18 14-18 8-18 10-14 10-16 UBC 10-18 12-16 12-18 14-18 3.62 3.58 4.16 4.28 3.98 4.08 3.72 3.71 3.87 4.01 3.55 3.54 3.27 3.14 3.76 3.66 4.29 4.45 4.04 4.07 3.88 3.82 3.88 3.96 3.72 3.68 3.47 3.20 3.69 3.70 4.19 4.25 4.05 4.12 3.79 3.78 4.02. 4.28 3.69 3.78 3.39 3.32 3.69 3.74 4.29 4.18 4.09 3.98 3.84 3.86 4.06 3.98 3.73 3.80 3.38 3.52 3.60 3.64 4.26 4.13 3.93 3.84 3.70 . 3.64 3.80 3.86 3.54 3.56 3.13 3.14 3.68 3.70 4.34 4.12 4.10 4.03 3.74 3.70 4.14 4.02 3.66 3.58 3.16 3.27 3.72 3.82 4.22 4.48 4.04 4.22 3.82 3.94 3.90 4.17 3.66 3.81 3.41 3.40 3.62 3.68 4.06 4.12 3.84 4.02 3.68 3.76 3.86 4.13 3.64 3.75 3.30 3.40 3.68 3.68 4.19 4.12 3.99 3.90 3.74 3.74 3.70 3.65 3.47 3.52 3.30 3.36 3.80 3.81 4.26 4.28 4.06 3.98 3.90 3.78 3.92 3.90 3.76 3.66 3.54 3.29 3.78 3.78 4.34 4.32 4.06 4.04 3.88 3.83 4.02 4.04 3.80 3.75 3.43 3.34 3.72 3.73 4.26 4.26 3.98 4.00 3.76 3.83 3.98 4.00 3.68 3.76 3.25 3.40 3.66 3.70 4.24 4.20 3.96 3.96 3.73 3.78 4.01 3.92 3.69 3.70 3.22 3.36 3.72 3.70 4.22 4.36 4.05 4.10 3.80 3.82 3.97 4.14 3.67 3. 76 3.39 3.28 3.64 3.70 4.25 4.25 3.98 4.04 3.70 3. 78 4.02 3.94 3.61 3.63 3.14 3.32 3.68 3.80 4.16 4.20 3.96 4.07 3.74 3.84 3.86 4.16 3.60 3.82 3.33 3.47 APPENDIX TABLE 3. MEAN EMBRYO GROWTH RATES BY SIRE AND DAM LINE OF MALE (M) FEMALE (F) FOR VARYING GROWTH PERIODS ACROSS REPLICATIONS S i r e l i n e Dam l i n e P e riod of BA MH NH UBC BA MH NH UBC growth (day) M F M F M F M F M F M F M F M F 6-10 3.86 3.79 3.93 3.88 3.88 3.86 3.88 3.80 3.73 3.68 3.95 3.93 3.91 3.82 3.96 3.90 6-12 3.98 3.88 3.98 3.92 4.00 3.96 3.93 3.88 3.89 3.83 4.04 3.99 3.98 3.92 3.98 3.90 6-14 4.04 4.04 4.07 4.05 4.07 4.05 4.05 4.03 3.97 3.94 4.11 4.12 4.08 4.07 4.08 4.05 6-16 3.97 3.95 3.96 3.97 3.96 3.93 3.94 3.95 3.87 3.84 4.02 4.00 3.98 3.99 3.96 3.97 6-18 3.82 3.79 3.80 3.80 3.84 3.82 3. 79 3.80 3.73 3.70 3.87 3.83 3.83 3.83 3.82 3.84 8-12 3. 72 3.62 3.71 3.76 3.84 3. 86 3.72 3.72 3.76 3.74 3.80 3.79 3.74 3. 76 3.69 3.66 8-14 3.89 3.92 3.93 3.98 3.98 4. 02 3.94 3.97 3.91 3.91 3.97 4.02 3.95 4. 02 3.92 3.93 8-16 3.84 3184 3.82 3.90 3.87 3. 88 3.84 3.88 3.80 3.80 3.89 3.90 3.86 3. 94 3.82 3.86 8-18 3.69 3.67 3.66 3. 71 3.74 3. 75 3.68 3.72 3.64 3.65 3. 74 3.72 3.71 3. 75 3.68 3.74 10-14 4.23 4.29 4.22 4.21 4.26 4.24 4.22 4.25 4.21 4.18 4.28 4.30 4.25 4.02 4.19 4. 19 10-16 4.04 4.06 3.98 4.03 4.02 3.98 3.99 4.05 3.97 3.95 4.06 4.05 4.03 4.11 3.96 4. 02 10-18 3.81 3.79 3.74 3.76 3.82 3.80 3.74 3.81 3.72 3. 72 3.83 3. 78 3.80 3.84 3.75 3. 82 12-16 3.96 4.06 3.92 4.04 3.91 3.90 3.96 4.04 3.84 3.86 3.98 4.01 3.99 4.11 3.94 4. 07 12-18 3.67 3.70 3.62 3.68 3.68 3.68 3.64 3.72 3.56 3.58 3.70 3.67 3.69 3. 74 3.66 3. 78 14-18 3.38 3.30 3.25 3.30 3.38 3.35 3.27 3.36 3.23 3.25 3.39 3.26 3.34 3.34 3.32 3. 45 APPENDIX TABLE 4. NUMBER OF POST-HATCH PROGENCIES FOR EACH SEX GENOTYPE AND " REPLICATION S i r e l i n e BA MH NH UBC T o t a l BA MH NH UBC T o t a l Dam l i n e R e p l i c a t i o n Male Female Male Female Male Female Male Female Male Female 1 40 47 58 48 48 45 49 50 195 190 2 46 41 47 50 46 42 45 56 184 189 1 47 37 31 42 51 51 57 42 186 172 2 49 57 38 39 51 45 52 47 190 188 1 46 52 48 49 41 44 46 46 181 191 2 54 53 51 40 46 59 48 38 199 190 1 54 47 39 41 39 44 43 46 175 178 2 50 48 59 39 56 53 43 45 208 185 1 187 183 176 180 179 184 195 184 737 731 2 199 199 195 168 199 199 188 186 781 752 

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