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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 I N 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 I N PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE  i n t h e Department of Poultry  Science  We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e required  standard  THE UNIVERSITY OF BRITISH COLUMBIA A u g u s t , 1972  In p r e s e n t i n g t h i s  thesis  an advanced degree at the L i b r a r y I  the U n i v e r s i t y  s h a l l make i t  freely  fulfilment of of B r i t i s h  available  for  the  requirements  Columbia, I agree  for  that  r e f e r e n c e and s t u d y .  f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying o f t h i s  for  thesis  s c h o l a r l y purposes may be granted by the Head o f my Department o r  by h i s of  in p a r t i a l  this  representatives.  It  thesis for financial  i s understood that copying o r p u b l i c a t i o n gain shall  not be allowed without my  written permission.  Kanok  Department o f  Poultry  Science  The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada  Date  August 30, 19 72.  Phalaraksh  ABSTRACT  A t o t a l o f 7,472 progeny f r o m 4 l i n e s o f c h i c k e n s , a B l a c k 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 c r o s s e s and r e c i p r o c a l c r o s s e s were a s s e s s e d  f o r t h e i r p r e - and p o s t - h a t c h i n g body w e i g h t s , p r e -  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 o f t h e s e t r a i t s as they i n f l u e n c e d growth and 7-week body w e i g h t were e v a l u a t e d .  The e f f e c t s o f t h e s e r e l a t i o n s h i p s were  j o i n t l y c o n s i d e r e d as they i n f l u e n c e d t h e g e n e t i c 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 ) o f t h e s e  traits.  The r e s u l t s o f t h e i n v e s t i g a t i o n showed t h a t an a d v e r s e e n v i r o n m e n t a l e f f e c t due t o 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 t o o k 2 weeks o f growth a f t e r h a t c h i n g f o r t h e c h i c k e n body w e i g h t s  to attain  the same l e v e l o f a s s o c i a t i o n w i t h 7-week body w e i g h t t h a t was p r e v i o u s l y shown i n t h e body w e i g h t s  o f 18-day o l d embryos.  Multiple regression  a n a l y s e s showed t h a t 1-week body w e i g h t and any subsequent growth p e 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 w e i g h t .  The h  e s t i m a t e s o b t a i n e d f o r a l l w e e k l y growth r a t e s as w e l l as t h e 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 s o u r c e o f 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 p o p u l a t i o n s t h a t h e r e t o f o r e has n o t b e e n d i r e c t l y u t i l i z e d i n body w e i g h t s e l e c t i o n p r o g r a m s .  ii  TABLE OF CONTENTS  Page INTRODUCTION  .  .  .  1  REVIEW OF THE LITERATURE  .  2  MATERIALS  .  15  AND METHODS  STATISTICAL  METHODS  . . . . . . .  RESULTS AND DISCUSSION .  19  „  25  Embryo Weights  25  Embryo Growth Rates . . . . . . .  .  P o s t - h a t c h i n g Body Weights  .  . . . . . .  38 57  P o s t - h a t c h i n g Growth Rates  72  P r e - and P o s t - s t o r a g e Egg Weights  .  Embryo C o r r e l a t i o n s  95 ^-04  Post-hatching Correlations  ,  106  C o r r e l a t i o n s o f Embryo and P o s t - h a t c h i n g Data Heritability  o f Embryo Weights  Heritability  of Post-hatching data  109 .  131  SUMMARY BIBLIOGRAPHY  .  APPENDIX  • . . . .  iii  129  .  141  .  145 151  LIST OF TABLES  Table 1  2  3  4  5  6  7  8  9  10  Page E x p e c t e d Mean Squares f o r t h e A n a l y s i s o f Body Weights and Growth R a t e s o f P r e - and P o s t - h a t c h Chick Data  21  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 E s t i m a t e s on t h e P r e - and P o s t Hatch Chick Data  24  Mean Embryo W e i g h t s 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 f r o m 6 t o 18 Days o f I n c u b a t i o n f o r M a l e and Female Progeny  26  Sums o f Squares f r o m t h e A n a l y s i s o f V a r i a n c e o f 6-Day Embryo W e i g h t s , C a l c u l a t i o n s Based on C e l l Means  .....  28  Sums o f Squares f r o m t h e A n a l y s e s o f V a r i a n c e of Mean Embryo Weights a t Two Day I n t e r v a l s f r o m 8 t o 18 days o f 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  Mean Embryo Weights o f M a l e s and Females By Replication  31  Sums o f Squares f r o m t h e A n a l y s e s o f V a r i a n c e o f Mean Embryo Weights o f Male Progeny a t Two Day I n t e r v a l s f r o m 8 t o 18 Days o f I n c u b a t i o n  32  S i r e and Dam L i n e Mean Embryo Weights o f M a l e Progeny f r o m 8 t o 18 Days o f I n c u b a t i o n  33  Sums o f Squares f r o m t h e A n a l y s e s o f V a r i a n c e of Mean Embryo Weights o f Female Progeny a t Two Day I n t e r v a l s from 8 t o 18 Days o f I n c u b a tion S i r e and Dam L i n e Mean Embryo Weights o f Female Progeny f r o m 8 t o 18 Days o f I n c u b a t i o n  iv  35  36  -  v  -  Table 11  12  Page Mean Embryo Growth R a t e s 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 f r o m 6 t o 18 Days of I n c u b a t i o n f o r M a l e and Female Progeny  39  Sums of 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 R a t e s a t Two Day I n t e r v a l s f r o m 6 t o 18 Days o f 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  Females  13  Mean Embryo Growth R a t e s of M a l e s and Replication  14  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 R a t e s of M a l e Progeny a t Two Day I n t e r v a l s f r o m 6 t o 18 Days of I n c u b a t i o n  15  16  17  18  by  S i r e and Dam L i n e Mean Embryo Growth R a t e s o f M a l e Progeny a t Two Day I n t e r v a l s f r o m 6 t o 18 Days o f Incubation  .....  42  43  .....  45  Sums o f Squares f r o m the A n a l y s e s o f V a r i a n c e o f "Mean Embryo Growth R a t e s o f Female Progeny a t Two Day I n t e r v a l s f r o m 6 t o 18 Days of I n c u b a t i o n  46  S i r e and Dam L i n e Mean Embryo Growth R a t e s o f Female Progeny a t Two Day I n t e r v a l s f r o m 6 to 18 Days of I n c u b a t i o n  47  Sums o f Squares f r o m the A n a l y s e s o f V a r i a n c e Mean Embryo Growth R a t e s 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  of  19  Mean Embryo Growth R a t e s of M a l e s 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 M a l e Embryo Growth R a t e s f o r V a r y i n g Growth Periods  52  S i r e and Dam L i n e Mean Embryo Growth R a t e s of M a l e Progeny f o r V a r y i n g Growth P e r i o d s f r o m 8 to 18 Days o f I n c u b a t i o n  53  21  - v i-  Table 22  23  24  25  26  27  28  29  30  31  32  33  34  Page Sums o f Squares f r o m t h e A n a l y s e s o f V a r i a n c e o f Mean Female Embryo Growth R a t e s f o r V a r y i n g Growth Periods S i r e and Dam Mean Embryo Growth R a t e s o f Female Progeny f o r V a r y i n g Growth P e r i o d s from 8 t o 18 -Days o f I n c u b a t i o n  55  56  Mean C h i c k Body Weights o f M a l e s and Females a t Weekly I n t e r v a l s from H a t c h t o 7 Weeks o f Age A c r o s s Replications  58  Sums o f Squares f r o m t h e A n a l y s e s o f V a r i a n c e o f Mean C h i c k Body Weights from H a t c h t o 7 Weeks o f 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  Mean C h i c k Body Weights o f M a l e and Female Progeny by R e p l i c a t i o n  ^1  Sums o f Squares f r o m t h e A n a l y s e s o f V a r i a n c e o f Mean Male Progeny Weights a t Weekly I n t e r v a l s f r o m H a t c h t o 7 Weeks o f Age  62  S i r e and Dam L i n e Mean Body Weights o f Male P r o geny f r o m H a t c h t o 7 Weeks o f Age  64  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 o f M a l e Progeny  66  Sums o f Squares f r o m t h e A n a l y s e s o f V a r i a n c e o f Mean Body Weights o f Female Progeny a t Weekly I n t e r v a l s f r o m H a t c h t o 7 Weeks o f Age  69  S i r e and Dam L i n e Mean Body Weights o f Female Progeny f r o m H a t c h t o 7 Weeks o f Age  71  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 o f Female Progeny  73  Mean C h i c k Growth R a t e s o f M a l e s and Females a t Weekly 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 f r o m H a t c h t o 7 Weeks o f Age  76  Sums o f Squares from t h e A n a l y s e s o f V a r i a n c e o f Mean C h i c k Weekly Growth R a t e s from H a t c h t o 7 Weeks o f A g e , 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 35  36  37  38  39  40 41  42  43  44  45 46 47  N  Page  Mean Chick Growth Rates of Male and Female Progeny by Replication  79  Sums of Squares from the Analyses of Variance of Weekly Growth Rates of Male Progeny from Hatch to 7 Weeks of Age  81  Sums of Squares from'the Analyses of Variance of Weekly Growth Rates of Female Progeny from Hatch to 7 Weeks of Age  82  Sire and Dam Line Mean Growth Rates of Male Progeny During Weekly Intervals from Hatch to 7 Weeks of Age  84  Sire and Dam Line Mean Growth Rates of Female Progeny During Weekly Intervals from Hatch to 7 Weeks of Age  85  Mean Chick Growth Rates of Males and Females for Varying Growth Periods Across Replications  87  Sums of Squares from the Analyses of Variance of Chick Growth Rates f o r Varying Growth Periods, Calculations Based on D i a l l e l C e l l Means  88  Mean Chick Growth Rates of Male and Female Progeny by R e p l i c a t i o n  90  Sums of Squares from the Analyses of Variance of Male Progeny f o r Varying Growth Periods  91  Sums of Squares from the Analyses of Variance of Female Progeny f o r Va??ying Growth Periods  92  S i r e and Dam Line Mean Growth Rates of Male Progeny f o r Varying Growth Periods  94  Sire and Dam Line Mean Growth Rates of Female Progeny f o r Varying Growth Periods  96  Mean Pre- and Post-Storage Egg Weights f o r the Hatched Progeny of Each Sire and Dam Line  97  - viii  -  Table 48  49  50  51  52  53  54  55  Page 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 P r e - and P o s t - S t o r a g e Egg W e i g h t s f o r Hatched Progeny  99  A n a l y s e s o f V a r i a n c e o f Mean Egg Weights T e s t i n g the S t o r a g e E f f e c t  100  Mean P r e - and P o s t - S t o r a g e Egg Weights by R e p l i c a t i o n fcr Hatched Progeny  .....  102  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 P r e - and P o s t - s t o r a g e Egg Weights  103  S i m p l e 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 P r e - and P o s t S t o r a g e Egg Weights w i t h Embryo Weights W i t h i n E a c h 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  S i m p l e 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 P r e - and P o s t s t o r a g e Egg Weights w i t h C h i c k Body Weights and Growth R a t e s 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 D a t a  1^7  S i m p l e 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 C h i c k Growth Rates w i t h Embryo Growth R a t e s 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 ( M a l e , R e p l i c a t i o n 1)  HO  S i m p l e 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 C h i c k Growth R a t e s w i t h Embryo Growth R a t e s 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 ( F e m a l e , R e p l i c a t i o n 1)  56  S i m p l e 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 C h i c k Growth R a t e s w i t h Embryo Growth R a t e s 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 ( M a l e , R e p l i c a t i o n 2)  57  S i m p l e 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 C h i c k Growth R a t e s and Embryo Growth R a t e s 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 ( F e m a l e , R e p l i c a t i o n 2)  .....  m  ^3  - ix -  Table 58  59  60  61  62  63  64  65  66  Page S i m p l e 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 7 Week Body Weights w i t h Embryo W e i g h t s and C h i c k Weights W i t h i n Each Sex and R e p l i c a t i o n 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 7 Week Body Weights w i t h Embryo Growth Rates and C h i c k Growth Rates w i t h i n E a c h Sex and R e p l i c a t i o n 2 C o e f f i c i e n t s o f D e t e r m i n a t i o n (100 X R ) o f I n d i v i d u a l E s t i m a t e s o f 7 Week Body W e i g h t s 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 R e g r e s s e d on S e l e c t e d T r a i t s 2 C o e f f i c i e n t s o f D e t e r m i n a t i o n (100 X R ) o f H a t c h i n g Weights M u l t i p l e R e g r e s s e d on S e l e c t e d Traits 2 C o e f f i c i e n t s o f D e t e r m i n a t i o n (100 X R ) o f 1-Week Body Weights M u l t i p l e R e g r e s s e d on Selected T r a i t s  .....  H8  120  123  126  128  H e r i t a b i l i t y E s t i m a t e s o f Embryo W e i g h t s , C a l c u l a t i o n s Based on S e p a r a t e d Sex i n Each Replication.  130  H e r i t a b i l i t y E s t i m a t e s and S t a n d a r d E r r o r o f Egg W e i g h t s , C h i c k Growth R a t e s and Body Weights ( R e p l i c a t i o n 1)  132  H e r i t a b i l i t y E s t i m a t e s and S t a n d a r d E r r o r o f Egg W e i g h t s , C h i c k Growth R a t e s and Body Weights ( R e p l i c a t i o n 2) H e r i t a b i l i t y E s t i m a t e s o f Egg W e i g h t s , C h i c k Growth R a t e s and Body W e i g h t s , C a l c u l a t i o n s Based on t h e Averages A c r o s s R e p l i c a t i o n s  ..... I  3  3  13^  ACKNOWLEDGEMENT  The a u t h o r i s v e r y g r a t e f u l t o D r . C.W. R o b e r t s who p r o v i d e d s u p e r v i s i o n , s u g g e s t i o n s and f a c i l i t i e s f o r t h i s s t u d y .  He would a l s o  l i k e t o e x p r e s s h i s a p p r e c i a t i o n t o M r . C . J . W i l l i a m s and D r . R.G. P e t e r s o n f o r t h e i r L e a s t - s q u a r e s a n a l y s i s computer p r o g r a m . The a u t h o r w i s h e s t o e x p r e s s h i s g r a t i t u d e t o t h o s e members o f t h e F a c u l t y who r e a d t h e m a n u s c r i p t 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 e x p r e s s e d f o r t h e a s s i s t a n c e g i v e n b y f e l l o w s t u d e n t s 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 c o u l d n o t have been u n d e r t a k e n w i t h o u t t h e f i n a n c i a l a s s i s t a n c e o f Canadian government.  I n p a r t i c u l a r , the author wishes t o  thank t h e Canadian I n t e r n a t i o n a l Development Agency.  x  INTRODUCTION  i The g e n e t i c and e n v i r o n m e n t a l i n f l u e n c e o f e a r l y growth r a t e on subsequent body w e i g h t performance i n t h e g r o w i n g c h i c k e n i s n o t w e l l defined.  G e n e t i c i s t s have used body w e i g h t a t a g i v e n age as t h e s o l e  c r i t e r i a o f s e l e c t i o n t o improve body w e i g h t i n b r o i l e r s t o c k .  The c o n -  sequence o f such s e l e c t i o n h a s tended t o i n c r e a s e egg s i z e and l o w e r egg production.  T h i s i s due t o t h e n e g a t i v e 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 t h e s e t r a i t s . Recent work b y Deland (1965) i n v e s t i g a t e d t h e power f u n c t i o n (y = a t ^ ) , p r o p o s e d by R o b e r t s ( 1 9 6 4 ) , as a method by w h i c h t h e growth r a t e (b) c o u l d be measured g e n e t i c a l l y .  D e l a n d compared t h e p r e - and p o s t -  h a t c h i n g growth p e r i o d s and found a s t r o n g i n d i c a t i o n t h a t growth r a t e c o u l d 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 i m p r o v i n g body w e i g h t . The p u r p o s e o f t h i s p r e s e n t s t u d y was t o d e t e r m i n e the g e n e t i c w o r t h o f t h e 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 t o 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  H a l b e r s l e b e n and M u s s e h l (1922) showed t h e r e was  a consistent  r e l a t i o n s h i p between t h e w e i g h t o f the egg used f o r h a t c h i n g and t h e w e i g h t of the c h i c k at h a t c h . weight.  The c h i c k w e i g h t averaged 64 p e r c e n t o f the egg  However, a t 35 days o f age any a p p a r e n t advantage p o s s e s s e d by  c h i c k s h a t c h e d from l a r g e e g g s , had n e a r l y d i s a p p e a r e d . W i l e y (1950 b) found t h a t s m a l l eggs used f o r h a t c h i n g gave the c h i c k s a d e c i d e d body weight disadvantage a t h a t c h i n g . t h e t w e l f t h week.  T h i s d i s a d v a n t a g e was l a r g e l y overcome by  There was no c o n s t a n t 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 , o r h a t c h a b i l i t y i n f a v o u r o f e i t h e r egg w e i g h t g r o u p s . Godfrey et a l .  (1953) s t u d i e d p h e n o t y p i c c o r r e l a t i o n s o f t h e dam egg  size,  age a t s e x u a l m a t u r i t y , and a d u l t body w e i g h t w i t h b i - w e e k l y w e i g h t s o f i n d i v i d u a l s t o 12 weeks o f age and i n d i c a t e d t h a t t h e i n f l u e n c e o f egg s i z e on e a r l y growth d e c r e a s e s r a p i d l y a f t e r 2 weeks o f age and has no a p p r e c i a b l e e f f e c t on w e i g h t a t b r o i l e r a g e .  They found t h a t t h e combined  i n f l u e n c e o f egg w e i g h t , age a t s e x u a l m a t u r i t y and a d u l t body w e i g h t a c c o u n t e d f o r about 36 p e r c e n t of the v a r i a t i o n observed i n body w e i g h t a t 12 weeks o f a g e .  L e s s o f t h e o b s e r v e d v a r i a t i o n i n body w e i g h t  was  a c c o u n t e d f o r by t h e s e f a c t o r s a t 2 , 4 , 6, 8 and 10 weeks o f a g e .  At  h a t c h i n g however, due t o t h e r e l a t i v e l y l a r g e i n f l u e n c e o f egg s i z e , t h e s e t h r e e f a c t o r s a c c o u n t e d f o r about 74 p e r c e n t of the o b s e r v e d v a r i a t i o n i n body w e i g h t . - 2 -  Upp  (1928) c o n c l u d e d t h a t egg w e i g h t and c h i c k w e i g h t a t h a t c h i n g  were h i g h l y c o r r e l a t e d ( r = 0.79)  but t h a t 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 i n d e x o f c h i c k w e i g h t a t 2, 4 o r 12 weeks o f a g e .  J u l l and Heywang  (1930) f o u n d t h e p e r c e n t y o l k w e i g h t o f c h i c k w e i g h t a t h a t c h i n g t i m e was independent of the sex of the c h i c k .  They a l s o showed t h a t the p e r c e n t  c h i c k w e i g h t of i n i t i a l egg w e i g h t was independent of i n i t i a l egg w e i g h t , i.e.  -  r e g a r d l e s s of t h e i n i t i a l egg w e i g h t the p e r c e n t c h i c k w e i g h t s  tended t o be the same.  Y o l k m a t e r i a l formed about 18 p e r c e n t o f c h i c k  w e i g h t a t h a t c h and the c o r r e l a t i o n o f egg and embryo w e i g h t s  increased  during yolk a s s i m i l a t i o n . O ' N e i l (1950) used two h a t c h e s of B a r r e d Plymouth Rock c h i c k s t o t e s t t h e e f f e c t o f p e r c e n t s i z e o f 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 t o 8 weeks o f 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 b o t h sexes  t h o s e c h i c k s h a t c h i n g w i t h the h i g h e s t p e r c e n t a g e of t h e o r i g i n a l w e i g h t o f the egg were h e a v i e r a t 8 weeks o f a g e , more e f f i c i e n t i n f e e d and had a l o w e r r a t e o f m o r t a l i t y .  He mentioned  consumption  t h a t t h e r e was a  signifi-  c a n t d i f f e r e n c e i n s e x r a t i o s f a v o u r i n g the m a l e s i n the group t h a t had t h e l a r g e r p e r c e n t a g e of the o r i g i n a l egg w e i g h t and f a v o u r i n g t h e f e m a l e s i n the other group.  C h i c k s 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 t o c h i c k s from s m a l l eggs ( K o s i n et^ a]L., 1 9 5 2 ) . Skoglund e t a l . ( 1 9 5 2 ) 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 a t 12 weeks of age when a l l b i r d s were r e a r e d  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 h a t c h i n g w e i g h t ,  - 4 -  egg s i z e , c h i c k s i z e , and growth r a t e t o f r y e r age.  He s u g g e s t e d t h a t the  s i z e o f a c h i c k a t h a t c h i n g had an i m p o r t a n t e f f e c t on i t s growth t o b r o i l e r a g e , even though the s m a l l e r c o r r e l a t i o n o f 9 week w e i g h t 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 o f h a t c h i n g w e i g h t w i t h egg w e i g h t 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 . et  al.,  C o n t r a r i l y , Godfrey  (1953) as mentioned b e f o r e , and Pope and S c h a i b l e (1957) c o n c l u d e d  t h a t the e f f e c t o f egg s i z e on e a r l y growth d e c r e a s e d r a p i d l y a f t e r the f i r s t few weeks o f age and had no a p p r e c i a b l e e f f e c t on w e i g h t a t b r o i l e r age.  However, they mentioned t h a t t h e above r e l a t i o n s h i p might not h o l d  t r u e f o r a l l b r e e d s 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 f a v o u r o f t h e h e a v i e r egg w e i g h t groups f o r p e r c e n t f e r t i l i t y , p e r c e n t h a t c h a b i l i t y o f t o t a l eggs s e t , and body w e i g h t .  E s s e n t i a l l y , no  difference  was p r e s e n t f o r p e r c e n t h a t c h o f f e r t i l e e g g s , p e r c e n t m o r t a l i t y and p e r c e n t condemnation.  Egg w e i g h t g r o u p s , when i n t e r m i n g l e d , tended t o have g r e a t e r  t o t a l m o r t a l i t y and w e i g h l e s s a t a g i v e n age as compared t o t h e same egg w e i g h t groups penned and r e a r e d s e p a r a t e l y . Godfrey and W i l l i a m s (1955) used the w e i g h t s o f t h e d a y - o l d c h i c k as a p e r c e n t a g e o f o r i g i n a l egg w e i g h t (719 New Hampshire c h i c k s ) t o p r e d i c t body w e i g h t a t 12 weeks o f age. in  Only about 5 p e r c e n t o f t h e t o t a l v a r i a t i o n  12-week body w e i g h t c o u l d be a c c o u n t e d f o r by the p e r c e n t the d a y - o l d  c h i c k was  o f the o r i g i n a l egg w e i g h t ; t h u s , t h i s r a t i o was  no v a l u e i n p r e d i c t i n g growth  of p r a c t i c a l l y  rate.  B r a y 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 t o egg w e i g h t i n 5 s t r a i n s o f d o m e s t i c f o w l , and demonstrated  that  - 5 -  the s i z e o f the egg  can be r e g a r d e d as a temporary e n v i r o n m e n t a l i n f l u e n c e  w h i c h 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 o f i n c u b a t i o n i n t h e i r s t o c k , and i n c r e a s e d g r a d u a l l y t o a maximum a t h a t c h i n g size.  The  t i m e when egg s i z e a l m o s t c o m p l e t e l y  determined chick  e f f e c t r a p i d l y d e c r e a s e d as the c h i c k s became o l d e r .  The  i n f l u e n c e o f b r e e d and s t r a i n upon the growth o f 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) a n a l y z e d  the  d a t a f r o m the U n i v e r s i t y o f I l l i n o i s s t r a i n o f pure b r e d S i n g l e Comb W h i t e Leghorns and f r o m pure b r e d 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  tween the embryo w e i g h t s o f the two b r e e d s and c o u l d be d e t e c t e d .  be-  t h e i r r e c i p r o c a l crosses  B y e r l y (1930) demonstrated t h a t c r o s s e s  gave a s l i g h t  d i f f e r e n c e i n s i z e o f embryos a t the same s t a g e of i n c u b a t i o n , f r o m eggs o f the same s i z e , b u t  these d i f f e r e n c e s d i s a p p e a r e d a t h a t c h i n g .  l a t e r s t u d y ( B y e r l y , 1922) r a t e w h i c h was  n o t e d t h a t each embryo had  an i n h e r e n t  m o d i f i e d p r o p o r t i o n a l l y t o d i f f e r e n c e s i n the  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 o f egg s i z e .  In a growth  immediately  B l u n n and  Gregory  (1955) found t h a t a s t u d y of w e i g h t s a l o n e 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 W h i t e Leghorn and Rhode I s l a n d Reds, but  a s t u d y o f c e l l s i z e , number and  differences existed.  r a t e o f m i t o s i s showed t h a t  B y e r l y e t 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 o f embryos ( m a t i n g between two  strains with reciprocal  crosses)  and  f r o m one  a n o t h e r d u r i n g t h e f i r s t week o f i n c u b a t i o n .  to  c o n c l u d e d t h a t they d i d n o t 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 D u r i n g the  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  11  slightly  - 6 -  h e a v i e r t h a n the g e n e t i c a l l y s m a l l e r embryos, even i n eggs o f s i m i l a r weight. A comparison of embryo w e i g h t s , c e l l c o u n t s and c e l l s i z e of two l i n e s o f B a r r e d Plymouth Rocks was  conducted by W i l e y ( 1 9 5 0 a ) .  He d i d n o t  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 w e i g h t s between the two l i n e s , b u t 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 t o c e l l number p e r u n i t a r e a o f 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 t o the c e l l  size.  McNary elt a l . (1960) measured t h e r a t e o f embryonic growth by t h e number o f s o m i t e s p r e s e n t a f t e r 38 h o u r s o f i n c u b a t i o n , embryo w e i g h t a f t e r 1 and 2 weeks o f i n c u b a t i o n of f o u r i n b r e d l i n e s , t h e i r c r o s s e s and r e c i p r o cals.  Growth d i f f e r e n c e s i n the embryos were o b s e r v e d a t a l l t h r e e  stages.  H e t e r o s i s f o r embryo growth was apparent a t a l l s t a g e s , b u t t h e e f f e c t was p a r t i a l l y o b s c u r e d by a m a t e r n a l e f f e c t t r a n s m i t t e d by one l i n e , w h i c h 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 t h a t  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 t h o s e f r o m t h e light lines.  B r a y and I t o n (1962) a l s o o b s e r v e d g e n e t i c d i f f e r e n c e s i n  embryo w e i g h t s from the t e n t h t o n i n e t e e n t h  day of i n c u b a t i o n .  Coleman  e t a l . (1964) s t u d i e d embryonic development o f two l i n e s o f White Rocks.  Plymouth  They o b s e r v e d embryo w e i g h t s o f a l i n e s e l e c t e d f o r h i g h body  w e i g h t were h e a v i e r t h a n t h o s e of a l i n e s e l e c t e d f o r l o w body w e i g h t a t 14 t o 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 w e i g h t and embryo w e i g h t : r ( h i g h body w e i g h t a t 17 days o f i n c u b a t i o n ) = 0.47; r ( l o w body w e i g h t a t 1 5 , 17 and 19 days o f  incubation)  - 7-  = 0.34, 0.40 and 0 . 6 0 , r e s p e c t i v e l y . Murray  (1925) p l o t t e d t h e L o g , o f embryo w e i g h t a g a i n s t L o g , o f  t i m e and o b s e r v e d an a p p a r e n t l y s t r a i g h t l i n e .  He c a l c u l a t e d t h e l e a s t  s q u a r e s l i n e o f b e s t f i t t o t h e d a t a and r e p o r t e d t h a t t h e a v e r a g e w e i g h t o f c h i c k e n embryos between 5 and 19 days o f i n c u b a t i o n , a s found by o v e r 3 6 600 embryo w e i g h i n g s , may be e x p r e s s e d by t h e e q u a t i o n , W = K t  , where  K = 0.668, W e x p r e s s e s embryo w e i g h t and t _ r e f e r s t o t i m e i n days f r o m s t a r t o f i n c u b a t i o n and 3.6 = t h e growth r a t e o f t h e i n d i v i d u a l .  Lerner  (1939) examined t h e d e v i a t i o n s f r o m l i n e a r i t y p r e s e n t i n t h e d a t a o f M u r r a y and o t h e r s and r e p o r t e d t h a t w h i l e i n d i v i d u a l s e t s o f d a t a may produce s a t i s f a c t o r y f i t t o a l o g by l o g s t r a i g h t l i n e , s m a l l d e v i a t i o n s i n t h e same d i r e c t i o n and a p p e a r i n g a t t h e same t i m e i n t h e m a j o r i t y o f s e t s o f r e l i a b l e d a t a cannot be d i s r e g a r d e d .  L e r n e r and Asmundson (1938) demon-  s t r a t e d t h e d i f f e r e n c e s i n t h e growth r a t e o f Murray's f u n c t i o n between b r e e d s and s t r a i n s and between s e x e s .  The d e c r e a s e d 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 h a t c h e s w i t h i n b r e e d s was found t o l e a d t o 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 b r e e d s  r e f l e c t e d the differences i n adult weight.  D e f i n i t i v e weights w i t h i n  b r e e d s were found t o be independent o f t h e d i f f e r e n t i a l p a t t e r n s o f growth i n the e a r l y s t a g e s . R o b e r t s (1964) proposed t h e power f u n c t i o n Y = at* 5 t o c a l c u l a t e w e e k l y 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 t h e d a t a d u r i n g t h e p e r i o d from h a t c h t o 10 weeks o f a g e . I n t h i s f o r m u l a , age was e x p r e s s e d a s t i m e from c o n c e p t i o n ; Y_ i s t h e c h i c k body w e i g h t a t time _ t ,  a_ i s . t h e body  - 8-  w e i g h t a t t i m e 0 , and b^ r e p r e s e n t s t h e growth r a t e .  H i s r e s u l t s showed  t h a t t h e w e e k l y growth r a t e s r e f l e c t e d a degree o f l i n e a r i t y up t o 7 o r 8 weeks o f a g e , and t h a t when t h e s e w e e k l y v a l u e s to 7 weeks o f age were a v e r a g e d , t h e 7-week g r o w t h r a t e p r o v i d e d a u s e f u l e s t i m a t e f o r c o m p a r i s o n of  genetic worth of i n d i v i d u a l s o r s t r a i n s .  J u l l and Quinn (1925)  inves-  t i g a t e d t h e r e l a t i o n s h i p between t h e w e i g h t o f eggs and t h e w e i g h t o f c h i c k s a c c o r d i n g t o s e x and c o n c l u d e d t h a t t h e r e was no s i g n i f i c a n t  differ-  ence i n the w e i g h t o f male c h i c k s and t h e w e i g h t o f f e m a l e 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  l o w e r mean w e i g h t t h a n y e a r l i n g - h e t f e g g s , t h e c h i c k s h a t c h e d from p u l l e t eggs w i l l a l s o t e n d to have a s i g n i f i c a n t l y l o w e r mean w e i g h t t h a n t h e c h i c k s h a t c h e d from y e a r l i n g - h e n e g g s .  Monro and K o s i n (1940) o b s e r v e d t h e  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 w e i g h t and egg weight. the  They n o t e d t h a t w h i l e t h e s e x o f t h e c h i c k was n o t governed by  w e i g h t o f the f r e s h e g g , t h e r e was a s e x d i f f e r e n c e i n t h e w e i g h t o f  d a y - o l d male and f e m a l e s i b s .  The d i f f e r e n c e was i n f a v o u r o f m a l e s ,  r a n g i n g from 0.6 t o 0.8 p e r c e n t when body w e i g h t was e x p r e s s e d as a p e r c e n t a g e o f egg w e i g h t . E v i d e n c e o f b r e e d and s e x d i f f e r e n c e s i n t h e w e i g h t o f c h i c k s h a t c h e d from eggs o f s i m i l a r w e i g h t s was s t u d i e d by G o d f r e y and Jaap  (1952).  They found t h a t t h e d i f f e r e n c e s i n body w e i g h t were u s u a l l y n o t p r e s e n t a t h a t c h i n g due t o t h e e f f e c t s o f egg s i z e . From t h e s t a t i s t i c a l s t u d i e s o f v a r i a t i o n o f body w e i g h t d u r i n g t h e growth p e r i o d o f s i n g l e Comb White L e g h o r n s , Funk e t a l . ,  (1930) c o n c l u d e d  - 9 -  t h a t c h i c k s 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 t h a t t h e i n i t i a l  c h i c k w e i g h t s and subsequent w e i g h t s were n o t c o r r e l a t e d , b u t c h i c k w e i g h t s at 4 , 8, 16 and 24 weeks o f 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 other.  Jaap and M o r r i s (1937) p o i n t e d out t h a t growth t o 8 weeks o f age  appears t o be a s e p a r a t e e n t i t y and n o t n e c e s s a r i l y r e l a t e d t o a d u l t w e i g h t . In the  t h e d a t a o f Hammond and B i r d (1942) t h e r e was a b a s i c p a t t e r n i n  body w e i g h t v a r i a t i o n o f c h i c k s .  Under i d e a l c o n d i t i o n s t h e c o e f f i c i e n t  of v a r i a t i o n o f body w e i g h t i n c r e a s e d r a p i d l y from h a t c h i n g t o 4 weeks o f age a f t e r w h i c h i t d e c r e a s e d a t t h e same r a t e t o 10 weeks o f a g e , t h e n d e c r e a s e d more s l o w l y u n i t i l i t reached a low c o n s t a n t v a l u e a t m a t u r i t y . When c h i c k s were d e p r i v e d o f an optimum d i e t , maximum v a r i a b i l i t y d i d n o t o c c u r u n t i l t h e s i x t h o r s e v e n t h week o f a g e . D e l a n d (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 6week growth r a t e and 6-week body w e i g h t ( r = 0 . 8 6 ) .  He c o n c l u d e d t h a t i n  g e n e r a l , 6-week body w e i g h t o f i n d i v i d u a l s b o r e a h i g h l y  significant  r e l a t i o n s h i p w i t h a l l w e e k l y growth r a t e s , and the peak o f s i g n i f i c a n c e o c c u r r e d d u r i n g the second week's growth r a t e .  He a l s o showed t h a t 92 p e r -  c e n t o f t h e v a r i a t i o n i n 6-week body w e i g h t c o u l d be a s s o c i a t e d w i t h t h e combined v a r i a t i o n o f 8-12 day embryo growth r a t e , h a t c h i n g w e i g h t and 6-week growth  rate. 2  Schmidt (1919) f i r s t used the d i a l l e l m a t i n g (n. m a t i n g from i i males w i t h i i f e m a l e s ) t o i n v e s t i g a t e the i n h e r i t a n c e o f v e r t e b r a e number in  the t r o u t , and he a l s o (1922) used t h i s s y s t e m o f m a t i n g i n t h e d o m e s t i c  - 10 -  fowl.  Schmidt suggested t h a t d i a l l e l m a t i n g s m i g h t be used t o e v a l u a t e t h e  g e n e t i c m e r i t o f an i n d i v i d u a l w i t h r e s p e c t 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 m o d i f i e d d i a l l e l m a t i n g t o s t u d y n o n - a d d i t i v e gene e f f e c t s i n t h e y i e l d o f 45 s i n g l e c r o s s e s o f 10 i n b r e d lines of corn.  I n t h i s s t u d y i t was found t h a t g e n e r a l c o m b i n i n g  ( a d d i t i v e g e n e t i c e f f e c t ) was more i m p o r t a n t  ability  than s p e c i f i c combining  ability  ( n o n - a d d i t i v e g e n e t i c e f f e c t ) among u n t e s t e d l i n e s , b u t t h e s i t u a t i o n was r e v e r s e d among t e s t e d l i n e s .  Using d i a l l e l matings, Lerner  (1945) and H a z e l  and Lamoreux (1947) s t u d i e d t h e i m p o r t a n c e o f n o n - a d d i t i v e gene e f f e c t s i n the s e x u a l m a t u r i t y of f l o c k s o f S i n g l e Comb White L e g h o r n s s e l e c t e d f o r h i g h egg p r o d u c t i o n .  Lerner s e l e c t e d matings i n which  mated a t d i f f e r e n t times t o each o f 2 d i f f e r e n t s i r e s . f u l l - s i b f a m i l i e s ranged f r o m  3 to 6 p u l l e t s .  2 dams h a d been The s i z e o f t h e  The e x p e r i m e n t o f H a z e l  and Lamoreux i n v o l v e d 3 s e r i e s o f m a l e s ; each s e r i e s h a d 60 s i n g l e male pens w i t h  6 females p e r p e n .  The a v e r a g e f u l l - s i b f a m i l y s i z e was 6.31.  B o t h 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 t h e n o n - 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 o n l y one p e r c e n t  i n the v a r i a t i o n of sexual m a t u r i t y .  found t h a t m a t e r n a l e f f e c t s were e s t i m a t e d  H a z e l and Lamoreux  t o a c c o u n t f o r about 5 p e r c e n t  o f t h e v a r i a t i o n i n body w e i g h t , b u t no i n f l u e n c e on s e x u a l m a t u r i t y c o u l d be d e m o n s t r a t e d . K a n , e t a l . (1959) used a t o t a l o f 119 d i a l l e l a n a l y s e s t o i n v e s t i g a t e t h e i m p o r t a n c e of n o n - 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 w e i g h t and 9-week w e i g h t .  He found t h a t t h e n o n - a d d i t i v e  - 11 -  gene e f f e c t s were o f c o n s i d e r a b l e i m p o r t a n c e i n c o n t r i b u t i n g t o t h e 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 d e p t h , b u t were o f q u e s t i o n a b l e i m p o r t a n c e as a c o n t r i b u t o r t o t h e v a r i a t i o n i n g a i n i n w e i g h t f r o m 4 t o 9 weeks and appeared t o have l i t t l e o r no e f f e c t on body w e i g h t a t e i t h e r 4 o r 9 weeks o f a g e . The d i a l l e l c r o s s method o f i n v e s t i g a t i n g t h e g e n e t i c a l p r o p e r t i e s o f a group o f 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 . has c o n s i d e r e d  some a s p e c t s o f t h e m e t h o d .  Hull  (1945)  A s h o r t summary o f a more g e n e r a l  a p p r o a c h by J i n k s and Hayman (1953) and i t s a p p l i c a t i o n t o s e v e r a l p u b l i s h e d s e t s o f maize d a t a h a s a l s o a p p e a r e d . on i n b r e d l i n e s o f Nicotiana  vustica  3  J i n k s (1954) has d e s c r i b e d e x p e r i m e n t s and has g i v e n an a c c o u n t o f some o f  the a s s o c i a t e d s t a t i s t i c s t o g e t h e r w i t h a d i s c u s s i o n o f t h e r e s u l t s .  Hayman  (1954) mentioned t h a t , e x p e r i m e n t s w i t h d i a l l e l c r o s s e s p r o v i d e d a p o w e r f u l method of i n v e s t i g a t i n g p o l y g e n i c s y s t e m s . s t a t i s t i c s obtained  H i s paper showed t h a t t h e v a r i o u s  f r o m measurements on t h e progeny p r o v i d e d  estimates of  the o v e r a l l degree o f dominance, p r o p e r t i e s o f the p a r e n t s , and o f t h e symm e t r y o r o t h e r w i s e o f t h e gene d i s t r i b u t i o n i n t h e l i n e s . Griffing  (1956) p o i n t e d out t h a t when i n t e r p r e t e d i n terms o f t h e  c l a s s i c a l method o f c o v a r i a n c e s between r e l a t i v e s , t h e method o f d i a l l e l c r o s s e s , y i e l d s e s t i m a t e s e q u i v a l e n t t o t h o s e o b t a i n e d by c o v a r i a n c e p a r e n t s and o f f s p r i n g .  between  Kempthome (1956) s t a t e d t h a t t h e 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 o f some p o p u l a t i o n w h i c h has g i v e n r i s e t o t h e homozygous p a r e n t s 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 n o t e x i s t then the whole a n a l y s i s can be q u e s tioned.  Goto and Nordskog (1959) e s t i m a t e d combining a b i l i t y from  diallel  c r o s s e s of 21 i n b r e d l i n e s , 12 o f these were w h i t e egg Leghorn t y p e s , w h i l e 9 were brown egg heavy b r e e d t y p e s .  They e s t i m a t e d v a r i a n c e s o f  g e n e r a l combining a b i l i t y , s p e c i f i c combining a b i l i t y , m a t e r n a l e f f e c t s reciprocal effects.  T h e i r r e s u l t s i n d i c a t e d t h a t g e n e r a l combining  and  ability  was more i m p o r t a n t t h a n s p e c i f i c combining a b i l i t y f o r a l m o s t a l l c h a r a c t e r s studied.  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 w e i g h t , n o t o n l y d u r i n g the growth (1-3 months o f age) b u t a l s o a t the t i m e a d u l t w e i g h t tained.  period  (10 months) was a t -  T h e r e f o r e , d i f f e r e n c e s i n the i n h e r e n t r a t e of a d u l t weight  may  have e x i s t e d i n t h e s e s t r a i n s b u t t h i s h y p o t h e s i s c o u l d n o t be c o n f i r m e d i n t h e i r study. 2 G o d f r e y and W i l l i a m s (1952) o b t a i n e d h e r i t a b i l i t y e s t i m a t e s (h ) f o r a l i n e o f S i l v e r O k l a b a r s w h i c h were s e l e c t e d f o r r a p i d g r o w t h , and  on  a n o t h e r l i n e w h i c h was  s e l e c t e d f o r s l o w g r o w t h . They o b t a i n e d a f t e r 2 2 g e n e r a t i o n s o f s e l e c t i o n , h e s t i m a t e s o f 0.19 and 0.30 f o r body w e i g h t a t 6 weeks o f a g e , and e s t i m a t e s of 0.31 and 0.32 f o r body w e i g h t a t 12 weeks 2  o f age f o r the f a s t and s l o w l i n e , r e s p e c t i v e l y .  Estimates of h  calculated  f o r males were c o n s i s t e n t l y l o w e r a t b o t h ages than t h o s e c a l c u l a t e d f o r 2 females. of a g e .  Goodman and Godfrey  (1956) e s t i m a t e d h  T h e i r e s t i m a t e averaged 0.43.  o f body w e i g h t a t 9 weeks  They c o n c l u d e d 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 t h e 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 small or non-existent f o r t h i s t r a i t .  Jerome e t a l . (1956) d i s -  2 c u s s e d t h a t the most r e l i a b l e h c o m b i n a t i o n o f t h e s i r e and dam  e s t i m a t e s were o b t a i n e d by t h e use o f a 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 t h e v a r i a b i l i t y o f e s t i m a t e s o b t a i n e d from o n l y 1 component and i n a d d i t i o n b r o u g h t t h e c o n t r i b u t i o n o f any s e x - l i n k e d o r m a t e r n a l  ef-  f e c t s i n l i n e w i t h t h e e f f e c t s t h e y would e x e r t i n a c t u a l b r e e d i n g p l a n s . In  an e x p e r i m e n t e x t e n d i n g o v e r 7 t r i a l s conducted by Thomas e t a l .  ( 1 9 5 8 ) , h e r i t a b i l i t i e s f o r body w e i g h t a t d i f f e r e n t ages were e s t i m a t e d f o r broilers.  The d a t a i n v o l v e d 1,196  p r o g e n i e s from 56 s i r e s and 218 dams.  They were a n a l y z e d on the b a s i s o f the mean performance o f t h e o f f s p r i n g o f 2 t h e same sex f r o m t h e v a r i o u s m a t i n g s . The e s t i m a t e s o f h o f w e i g h t a t v a r i o u s ages were g e n e r a l l y h i g h e r t h a n t h o s e p r e v i o u s l y r e p o r t e d f o r t h i s 2 character. for  A d i v e r g e n c e i n the e s t i m a t e s o f h  from m a l e and f e m a l e progeny  the same c h a r a c t e r p r e s e n t e d some e v i d e n c e t h a t s e x - l i n k e d genes a r e o f 2  considerable importance.  S i e g e l (1962) summarized t h e p u b l i s h e d h  estimates  2 of body w e i g h t s f o r ages r a n g i n g from 6 t o 12 weeks. ranged f r o m -0.20  The h  estimates  t o 1, however t h e h i g h e r f r e q u e n c i e s ranged from 0.20  0.60.  to  These e s t i m a t e s were based on s e v e r a l methods and t h e p a r a m e t e r s were 2 o b t a i n e d u s i n g many d i f f e r e n t p o p u l a t i o n s . However, t h e mode o f h estimates f o r 8 week body w e i g h t was v e r y 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 general, h populations.  o f 8-week body w e i g h t i s r e l a t i v e l y h i g h i n most p o u l t r y 2 Moyer et a l . (1962) e s t i m a t e d the h  4, 6 and 8 weeks of age on a p p r o x i m a t e l y  4,900 F  o f body w e i g h t a t c r o s s - b r e d progeny  - 14 -  from 96 s i r e s and 653 dams.  Heritability  e s t i m a t e d from t h e s i r e  variance  components appeared i n g e n e r a l t o i n c r e a s e s l i g h t l y between 4 and 8 weeks 2 o f age.  The s i r e component h  e s t i m a t e s f o r males a t 4 and 8 weeks o f  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 . Heritability  e s t i m a t e s f r o m t h e dam v a r i a n c e component compared t o t h o s e  from t h e s i r e were l a r g e r and g e n e r a l l y d e c r e a s e d between 4 and 8 weeks: 2 h e s t i m a t e s from t h e dam component o f v a r i a n c e f o r males a t 4 and 8 weeks o f 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 o f c h i c k e n s were used i n t h i s s t u d y : Australorp  ( B A ) , S i n g l e Comb White L e g h o r n  Black  ( L H ) , New Hampshire  (NH) and  the U n i v e r s i t y o f 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 b r e e d i n g p o p u l a t i o n  The  s i n c e 1964.  base s i z e o f t h e p o p u l a t i o n h a s n o t been l e s s t h a n 240 f e m a l e s and 80 males.  I t i s c h a r a c t e r i s e d b y medium body w e i g h t w i t h f a i r l y good egg  production. for  The MH l i n e has been a c l o s e d and random b r e e d i n g  a t l e a s t 15 y e a r s a t The U n i v e r s i t y o f B r i t i s h C o l u m b i a .  t y p i c a l egg p r o d u c t i o n and l a r g e egg s i z e .  population I ti s a  s t o c k , l i g h t body w e i g h t , a h i g h d e g r e e o f l i v a b i l i t y  The NH l i n e has been m a i n t a i n e d a t The U n i v e r s i t y o f  B r i t i s h Columbia as a random m a t i n g p o p u l a t i o n f o r a t l e a s t 18 y e a r s . combines medium body w e i g h t w i t h f a i r l y good egg p r o d u c t i o n .  It  The UBC l i n e  has been a c l o s e d b r e e d i n g p o p u l a t i o n s i n c e 1958 and random b r e d s i n c e 1 9 5 9 . I t i s c h a r a c t e r i z e d b y 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 w e i g h t . A t o t a l o f 100 hens and 16 males r e p r e s e n t e d each l i n e . each l i n e were randomized i n t o 4 groups o f 25 h e n s . i n i n d i v i d u a l cages. 4 groups.  Hens o f  A l l hens were housed  The 16 males o f each l i n e were randomly d i v i d e d i n t o  Each male group was randomly a s s i g n e d t o a female g r o u p .  The  male groups were r o t a t e d t h r o u g h o u t t h e f e m a l e s f o r each a r t i f i c i a l i n s e m i nation period.  The semen was c o l l e c t e d i n d i v i d u a l l y f r o m each male and  - 16 -  then i n s e m i n a t e d to 6 t o 7 h e n s .  A twice«sweekly r o t a t i o n o f the m a l e s 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 male e f f e c t s .  done i n o r d e r t o m i n i m i z e  This resulted i n a 4 x 4 l i n e d i a l l e l mating.  i n s e m i n a t i o n was performed t w i c e a week f o r 4 weeks.  individual  Artificial  Eggs were  gathered  d a i l y i d e n t i f i e d as t o o r i g i n , d a t e d and t h e n i n d i v i d u a l l y weighed and r e corded t o t h e n e a r e s t gram b e f o r e b e i n g p l a c e d d i r e c t l y i n t o a c o o l i n g room m a i n t a i n e d a t a p p r o x i m a t e l y 55°? and 60 p e r c e n t r e l a t i v e h u m i d i t y . were t u r n e d d a i l y . were t e s t e d .  A l l eggs  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 s a v i n g o f eggs  A f t e r 3 weeks o f c o l l e c t i o n , a l l eggs were re-weighed and  t r a y e d f o r i n c u b a t i o n . E a c h egg was i d e n t i f i e d as t o g e n e t i c o r i g i n and i t s w e i g h t a f t e r s t o r a g e , was o b t a i n e d f o r e a c h o f 4,000 eggs o f each r e p l i c a t i o n . B e f o r e t r a y i n g , t h e eggs o f e a c h m a t i n g were randomly d i v i d e d i n t o  2 groups;  t h o s e t h a t were a s s i g n e d f o r h a t c h i n g and t h o s e t h a t were a s s i g n e d f o r emb r y o w e i g h i n g d u r i n g i n c u b a t i o n . The eggs t h a t were a s s i g n e d f o r t h e embryo n i c t e s t were f u r t h e r randomly s u b d i v i d e d 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 t h a t a p p r o x i m a t e l y 7 eggs o f each week o f l a y were p r e s e n t i n each mating  subset.  One o f t h e 7 s u b s e t s would be b r o k e n o u t and t h e embryos  weighed on each o f t h e a l t e r n a t e days from 6 t o 18 days o f i n c u b a t i o n , i n clusive.  The c o r r e s p o n d i n g s u b s e t s o f each m a t i n g were t h e n b r o u g h t t o g e t h e r  and randomly d i s t r i b u t e d i n t o i n c u b a t o r t r a y s .  The t r a y s were t h e n randomly  d i s t r i b u t e d i n t o two Jamesway M o d e l 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 w i t h d r a w a l o f the t r a y s and t h e a c t u a l w e i g h i n g of  t h e embryos the a s s i g n e d t r a y s were w i t h d r a w n a t 48 hour i n t e r v a l s and  - 17 -  r e f r i g e r a t e d overnight. Before weighing, each embryo was separated from i t s extras-embryonic membranes by c u t t i n g the u m b i l i c a l cord at i t s juncture w i t h the abdomen. The embryo was then placed on a piece of absorbent paper f o r a few seconds i n order to d r a i n o f f 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 obv i o u s l y deformed embryos were discarded. Embryo weights were taken to the nearest thousandth of a gram.  The sex of the embryo was determined f o r a l l  embryos s t a r t i n g on the e i g h t h 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 a p p r o x i mately 5,000 eggs f o r the embryo experiment. Those eggs that were assigned f o r hatching were trayed a t random throughout the incubators. These eggs were candled a t 18 days of incubation and v i a b l e eggs were t r a n s f e r r e d i n t o i n d i v i d u a l hatching t r a y s .  Each t r a n s -  f e r r e d egg was placed under an i n v e r t e d polythene basket w i t h the i n d i v i d u a l w i r e frame covers. obtained.  I n t h i s f a s h i o n , i n d i v i d u a l hatching data could be  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 v a c c i n e . The chicks were d i s t r i b u t e d i n t o 4 f l o o r brooding pens. commercial b r o i l e r r a t i o n was fed techniques were followed.  ad  libitum.  A  Standard f l o o r brooding  A n t i b i o t i c was added to the d r i n k i n g water f o r  the f i r s t 3 days i n recommended amounts.  M o r t a l i t y was recorded d a i l y .  I n d i v i d u a l body weights i n grams were recorded weekly to 7 weeks of age.  - 18 -  The sex was d e t e r m i n e d by v i s u a l i n s p e c t i o n o r postmortem, and was r e c o r d e d a t 7 weeks o f age a t w h i c h time t h e t r i a l was  terminated.  As o n l y 1 body w e i g h t o b s e r v a t i o n c o u l d be made f o r any embryo, i t was i m p o s s i b l e t o c a l c u l a t e t h e i n d i v i d u a l embryonic growth r a t e s . assumed t h a t t h e growth r a t e s between  2  I t was  embryonic w e i g h i n g p e r i o d s c o u l d  be e s t i m a t e d f o r any m a t i n g genotype by u s i n g t h e average o f t h e embryonic w e i g h t s o f t h o s e i n d i v i d u a l s w i t h i n a m a t i n g genotype and s e x . growth r a t e e s t i m a t e s were c a l c u l a t e d f o r each o f t h e tween 6 and 18 days of i n c u b a t i o n , and t h e  Embryonic  2 -day p e r i o d s b e -  2 ^ a y e s t i m a t e s were a v e r a g e d  i n d i f f e r e n t c o m b i n a t i o n t o p r o v i d e v a l u e s 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 w e i g h t s o f i n d i v i d u a l progeny d u r i n g t h e growth phase  be-  tween h a t c h and 7 weeks o f age (as w e l l as t h a t o f t h e a v e r a g e d embryo body w e i g h t ) were assumed t o f o l l o w the power f u n c t i o n ( R o b e r t s , 1 9 6 4 ) , Y = a t ^ , where Y_ i s e q u a l t o t h e body w e i g h t o f t h e i n d i v i d u a l a t time _ t , a_ i s e q u a l t o t h e body w e i g h t o f t h e i n d i v i d u a l a t time z e r o o r a t c o n c e p t i o n , and b_ r e p r e s e n t s t h e growth r a t e o f t h e i n d i v i d u a l . Weekly growth r a t e e s t i m a t e s were c a l c u l a t e d between h a t c h i n g and 7 weeks o f age f o r each p r o g e n y .  The a v e r a g e d w e e k l y v a l u e s p r o v i d e d a  s i n g l e e s t i m a t e o f growth r a t e from h a t c h t o 7 weeks o f age (H-7 week growth rate).  STATISTICAL METHODS  The g e n e r a l model assumed t o e x p l a i n t h e s o u r c e s o f v a r i a t i o n i n the embryonic body w e i g h t s was: Y. .. = y + s . + d . + (sd) . . + f . + ( s f ) ljkl i J i J k i k r  l  +  ( s r )  i l  +  ( d r )  j l  +  ( f r )  kl  +  + ( d f ) .. + ( s d f ) . .. + j k xjk  ( s d r )  i j l  +  ( s f r )  ikl  +  (df r ) , + e. ., ... 'jkl ijkl where, ^ ' - j j ^ i  r e p r e s e n t s t h e averaged v a l u e o f each m a t i n g genotype within  each s e x and r e p l i c a t i o n ,  u  =  the p o p u l a t i o n p a r a m e t e r ,  s^  =  t h e e f f e c t o f t h e 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  fk r l  =  t h e e f f e c t o f t h e k t h s e x (k = 1 - 2 ) , the e f f e c t o f the 1 ^ r e p l i c a t i o n (1 = 1-2) ,  and e. .,n ljkl  =  t h e u n c o n t r o l l e d , random e n v i r o n m e n t a l and g e n e t i c d e v i a t i o n attributable  All effect  dam l i n e ( j = 1 - 4 ) ,  t o t h e m a t i n g c e l l mean.  e f f e c t s were c o n s i d e r e d t o be random e x c e p t f o r t h e r e p l i c a t i o n  ( r ^ ) w h i c h was c o n s i d e r e d t o be  fixed.  The g e n e r a l model assumed t o d e s c r i b e each o f t h e growth p e r i o d s was:  - 19 -  - 20 -  b . . . = yM + s . + d . + ( s d ) . . + f t + ( s f ) . , + ( d f ) . . + ( s d f ) . . , + ijkl 1 j i j k 'ik 'jk 'ljk ^  + isr)  ±1  +  (dfr)jkl + e  (dr)j;L + (sdr)ij;L + ( f r ) f c l + ( s f r ) i k l  l j k l  +  ,  w h i c h d i f f e r e d f r o m the model assumed t o d e s c r i b e t h e body w e i g h t o n l y i n the phenotype a n a l y z e d In  ( g r o w t h r a t e v s . body w e i g h t ) .  t h e a n a l y s e s o f v a r i a n c e o f t h e post-hatch d a t a , t h e average  v a l u e w i t h i n each m a t i n g genotype o f each sex and r e p l i c a t i o n was used as t h e 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 t o e x p l a i n t h e  s o u r c e s o f v a r i a t i o n o f t h e average body w e i g h t o b s e r v a t i o n s , a t h a t c h i n g and a t w e e k l y i n t e r v a l s t o 7 weeks o f age and each o f t h e growth p e r i o d s were analogous t o t h o s e used f o r t h e embryonic  data.  The e x p e c t e d mean s q u a r e s d e r i v e d from t h e models a r e shown i n T a b l e 1.  The s i m p l e 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 o f d e t e r m i n a t i o n  2 based on s i m p l e 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 d a t a as w e l l as from averaged d a t a w i t h i n t h e d i a l l e l m a t i n g 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 e x p e r i m e n t was, a c c o r d i n g 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 , the r e c i p r o c a l F^'s were i n c l u d e d .  1 s e t o f F ^ ' s , and  Each s e t c o n s i s t e d o f a l l p o s s i b l e  m a t i n g s o f 4 i n b r e d l i n e s , a n d was r e g a r d e d as a s e t o f "4 x 4" m a t i n g s . Assuming t h a t t h e e x p e r i m e n t a l 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 m a t i n g p o p u l a t i o n , t h e a d d i t i v e and n o n - a d d i t i v e  genetic  TABLE 1. EXPECTED MEAN SQUARES FOR THE ANALYSES OF BODY WEIGHTS AND GROWTH RATES OF PRE- AND POST-HATCH CHICK DATA  Source o f v a r i a t i o n S i r e l i n e (S) Dam l i n e (D)  d.f. 3 3  S x D  9 1  Sex (F) S x F  3  Expected mean s q u a r e s  a2 e + o  a  e +  °SDF  +  8  2  c2 + e + 2o2 SDF o  2  e +  S x D x F  9  o2 e + o  °DF  2  o  8a  2  SDF +  +  4  °SD  + 1 6  +  4a  SD  + 1 6  16  DF  +  16  °SF  +  2  3 2  °F  °SDF  2  4a2 + 4 2 e + DRF °SFR 16  °SR  2 °FR +  +  16  +  326  R  2  2 2 4a2 e + SFR + 2oSDR + 16o SR  3  D x R  3  a2 2 2 4a2 e + DFR + 2a SDR + 8a DR  S x D x R  9  a2 2a2 e + SDR  F x R  1  a2 .2 2 2 + 4o e + + 16a DFR SFR FR  S x F x R  3  D x F x R  3  a2 ,2 e + 4a SFR 2 a2 4 o e + DFR  Residual  9  a2 e  63  °D  2 °SF  S x R  Total  °S  2 + 8 aDF SDF  8a2 + DR  o  SF  2o2 4a2 e + SDF + SD  3  1  1 6 a  2  o2 e +  (R)  +  2  D x F  Replication  SDF  2a  2  2 °SDR  +  - 22 -  v a r i a n c e s o f t h e p a r e n t p o p u l a t i o n can be e s t i m a t e d .  T h i s experiment  assumed t h a t i t was d e a l i n g w i t h random samples from some p a r e n t p o p u l a t i o n , and i n f e r e n c e s a r e n o t t o be made about t h e i n d i v i d u a l l i n e s i n t h e t e s t b u t about t h e parameters o f t h e p a r e n t 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 e n v i r o n m e n t a l components o f t h e complex p o p u l a t i o n v a r i a n c e . Because o f d i s p r o p o r t i o n a t e s u b c l a s s numbers i n a l l t r a i t s  studied  t h e p r o c e d u r e o f 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) employed f o r t h e h e r i t a b i l i t y e s t i m a t e s .  was  The model assumed t o d e s c r i b e t h e  v a r i a b i l i t y o f 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. = t h e p o p u l a t i o n p a r a m e t e r , s^ = the e f f e c t o f t h e i * " * 1 s i r e l i n e ( i = l*-4) , d j = t h e e f f e c t o f t h e j * " * 1 dam l i n e  and e..^ X ^  ( j = 1-4),  = t h e u n c o n t r o l l e d , random e n v i r o n m e n t a l and g e n e t i c d e v i a t i o n a t t r i b u t a b l e t o t h e i n d i v i d u a l (k = 1-n..,). ijk  A l l e f f e c t s were c o n s i d e r e d  t o be random.  C a l c u l a t i o n s o f t h e a n a l y s e s o f v a r i a n c e , r e g r e s s i o n s and t i o n s were done on The U n i v e r s i t y o f B r i t i s h Columbia I.B.M.360/74  correlacomputer.  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 ( 1 9 6 0 ) , was used t o t e s t d i f f e r e n c e s between means w i t h i n t h e main e f f e c t s o f t h e a n a lyses of variance.  A l l the h y p o t h e s e s 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  a n a l y s e s was H: p = 0. The t e r m " s i g n i f i c a n t " was  used t o r e f e r t o d i f f e r e n c e s among sample  means w h i c h , on the b a s i s o f s t a t i s t i c a l a n a l y s i s , were e x p e c t e d t o r e f l e c t  - 23 -  true differences t h a n 0.05  among t h e p o p u l a t i o n - m e a n s w i t h a p r o b a b i l i t y o f n o t more  (P^O.05).  E s t i m a t i o n of V a r i a n c e Components and H e r i t a b i l i t y The a n a l y s i s i s g i v e n i n T a b l e 2.  o f v a r i a n c e used t o c a l c u l a t e  the v a r i a n c e components  The l c , c o e f f i c i e n t s o f 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 ( 1 9 6 0 ) .  The h e r i t a b i l i t y  (h ) was e s t i m a t e d  within  each s e x and r e p l i c a t i o n f r o m t h e s i r e component b y : 4 o2 S h 2 = s o^+o^+o^ +CJ2 S D (SD) ^ e and f r o m t h e dam component by A  h  2  d  .  £ -2 + 2+ 2 + °S ' "D ' "(SD) 4  j.  The s t a n d a r d e r r o r o f t h e h e r i t a b i l i t y e s t i m a t e s (S.E.) were c a l c u l a t e d u s i n g the f o r m u l a a f t e r Swiger e t a l . (1964); o S.E. ( h p = Where  4  /2(N-1) ( 1 - t ) 2 l + ( k - l ) t Y k (N-s) ( s - 1 )  2  N = number o f i n d i v i d u a l s , 2 t = intraclass correlation  (1/4 h ) ,  k = c o e f f i c i e n t o f v a r i a n c e component, and  s = number of s i r e l i n e s . 2  The s t a n d a r d e r r o r o f h e r i t a b i l i t y e s t i m a t e s f o r t h e 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 variation  Expected mean squares  d.f.  Sire l i n e (S)  In. - 1 . l l  Dam l i n e (D)  En. - 1 3  e  4 sd .,  2  °e  J  S x D  (En.. - 1)( En. i 3 1  Residual  1)  3  2+  .,  Vsd Vd  2  2 ,, 2 + k-.a e 1 sd  n... —En.En. i 3 X  Total  2  n...-1  En . 2  (n..,-E .1 En.En. - En. - En. + 1 i n. J i j X 2 2 En.. E En ..  1 J  1  k„ =  a  +  5 s  J  En. - 1 3  i  n.  2  2 2 E n. . n. . + E E ) - E i ij i n. j n.. 3 3 1 J  n.  2  En . 2  k„ =  EnT^l 3  (n  '-  - ^n.~.  n. = no. of s i r e i - 1 - 4  )  lines;  1  2  n. = no. of dam l i n e s ; j = 1 - 4  En . 2  k, =  _1_  En. - 1 .1 x  1 k. = — — . x x  1  x  I  in. 4  1  3  -EE  i  En. , . l , (n..-x_) n.  . n. J-3  n. ., = no. of i n d i v i d u a l s i n each d i a l l e l mating c e l l ; k = 1 - no. of i n d i v i d u a l i n each diallel cell.  RESULTS AND DISCUSSION  Embryo  Weights The number o f embryos s t u d i e d i n t h i s experiment f o r each  t i o n s e x and g e n o t y p i c m a t i n g i s p r e s e n t e d i n Appendix T a b l e 1.  replica-  A total  o f 4471 embryos were weighed 2,178 and 2,293 embryos i n t h e f i r s t and second replication,  respectively.  t o 50:50 as e x p e c t e d .  The s e x r a t i o s  i n b o t h r e p l i c a t i o n s were c l o s e  The number o f embryos at t h e same s t a g e o f i n c u b a t i o n  averaged i n each s e x , g e n o t y p i c m a t i n g and r e p l i c a t i o n  was about 8 , e x c e p t  f o r t h o s e o f embryos a t 6 days o f i n c u b a t i o n w h i c h were n o t s e x e d , and averaged f o r e a c h g e n o t y p i c m a t i n g and r e p l i c a t i o n  about 1 4 .  T a b l e 3 shows t h e mean embryo w e i g h t s r e c o r d e d a t 2 day from 6 t o 18 days o f i n c u b a t i o n .  intervals  I n g e n e r a l , t h e r e was f a i r l y good agreement  between t h e s i r e and dam l i n e averaged 6^day embryo w e i g h t s f o r each l i n e . However, t h e BA dam l i n e mean was 0.41 grams i n c o n t r a s t w i t h 0.36 grams f o r t h e s i r e l i n e mean. A t 18 days o f i n c u b a t i o n t h e s i r e and dam l i n e means o f t h e BA agreed f o r t h e male and female p r o g e n y .  The NH, MH and UBC s i r e and dam l i n e means  were i n good agreement f o r b o t h s e x e s o f t h e progeny a t 18 days o f a g e . Among t h e i n b r e d l i n e s , t h e NH l i n e had t h e h i g h e s t mean body w e i g h t a t 18 days o f age w i t h t h e v a l u e s o f 27 and 26 grams f o r m a l e and f e m a l e 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 t h e MH w i t h t h e mean  v a l u e s o f 24 and 23 grams f o r t h e male and female p r o g e n y . - 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  Sire BA Dam line  D  M  line  MH F  M  F  NH M  F  UBC  Mean  F  M  M  F  BA  6 8 10 12 14 16 18  1.34 2.72 5.89 11.08 18.00 25.36  0 .38 1.32 2.58 5.56 10.88 17.72 24.15  1.39 2.86 6.15 11.98 18.54 26.42  0 .40 1. 26 2. 88 5. 79 1 1 . 46 17. 74 2 5 . 26  1.33 2.84 6.55 11.76 18.99 27.10  0 .43 1.29 2.75 6.13 11.10 17.60 25.90  1.35 2.87 5.79 11.80 18.60 26.62  0 .43 1.29 2.74 5.72 11.18 17.84 26.12  1.35 2.82 6.09 11.65 18.54 26.37  0 .41 1.29 2.74 5.80 11.16 17.23 25.36  MH  6 8 10 12 14 16 18  1.20 2.48 5.50 10.50 16.88 25.18  0 .32 1.25 2.45 5.34 10.91 16.98 24.40  0 .32 1.18 1. 10 2.54 2. 49 5.26 5. 22 10. 78 9 . 95 17.50 16. 66 24.03 22. 88  1.22 2.61 5.72 10.99 17.80 26.68  0 .34 1.08 2.58 5.48 10.82 16.98 24.76  1.21 2.56 5.50 10.57 17.34 24.90  0 .32 1.22 2.48 5.18 10.68 17.26 24.48  1.20 2.54 5.48 10.71 17.38 25.20  0 .33 1.16 2.50 5.30 10.59 16.97 24.13  NH  6 8 10 12 14 16 18  1.33 2.77 5.85 11.32 18.72 26.76  0 .36 1.24 2.63 5.26 10.82 18.16 25.22  1.29 2.72 5.96 11.28 18.40 26.68  0.36 1. 18 2. 48 5.45 1 1 . 12 18. 26 26. 25  . 0 .36 1.26 1.18 2.66 2.65 5.64 5.55 11.38 11.25 18.16 17.94 27.03 26.10  1.33 2.87 5.85 11.84 18.78 26.16  0 .38 1.27 2.70 5.86 11.28 18.33 26.12  1.30 2.76 5.82 11.45 18.52 26.82  0 .36 1.22 2.61 5.53 11.12 18.17 25.92  UBC  6 8 10 12 14 16 18  1.36 2.72 5.77 11.44 18.72 26.92  0 .38 1.28 2.66 5.49 10.80 17.42 26.19  1.32 2.81 5.61 10.92 17.16 25.12  0 . 34 1.25 2.65 5.28 10.50 17.48 24.82  1.27 2.80 5.78 11.66 18.38 26.46  0 .34 1.29 2.71 5.64 11.29 18.02 26.56  1.26 2.71 5.79 10.98 17.68 25.50  0.36 1.16 2.62 5.30 10.66 17.68 25.60  1.30 2.76 5.74 11.25 17.99 25.80  0 .35 1.25 2.66 5.43 10.81 17.65 25.79  Mean  6 8 10 12 14 16 18  0 .36 1.30 1.27 2.58 2.67 5.41 5.75 11.09 10.85 18.08 17.57 26.06 24.99  1.30 2. 73 5.74 11.24 17.90 25.56  0 . 36 1.20 2.62 5.44 10.76 17.53 24.80  1.27 2.73 5.92 11.44 18.34 26.82  0 .37 1.21 2.67 5.70 11.11 17.64 25.83  0,.37 1.29 1.23 2.75 2.63 5.51 5.73 11.30 10.95 18.10 17.78 25.80 25.60  BA = B l a c k A u s t r a l o p ; MH - Mount Hope; NH = New Hampshire;  0 .36 1.23 1.29 2.72 2.63 5.52 5.79 11.27 10.92 18.10 17.63 26.06 25.30  UBC = UBC Leghorn l i n e .  - 27 -  I n t h e a n a l y s i s o f v a r i a n c e o f t h e 6-day embryo w e i g h t ( T a b l e 4) o f w h i c h no s e x was r e c o r d e d , t h e r e was a s i g n i f i c a n t dam e f f e c t significant sire effect.  and a n o n -  Comparing t h e means i n v o l v e d ( T a b l e 3) i t was  found t h a t t h e 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  t o the  MH l i n e h a v i n g the l o w e s t averaged v a l u e 0.33 grams w h i c h was s i g n i f i c a n t l y different  f r o m t h e NH l i n e (0.36 grams) and t h e UBC l i n e (0.35 grams)  w h i c h were n o t s i g n i f i c a n t l y d i f f e r e n t between t h e m s e l v e s , b u t 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  f r o m t h e BA l i n e (0.41 g r a m s ) .  the 4 s i r e l i n e s were n o t s i g n i f i c a n t l y d i f f e r e n t d i d n o t measurably d i f f e r :  As a c o m p a r i s o n ,  and t h e i r average v a l u e s  MH ( 0 . 3 6 ) , NH ( 0 . 3 7 ) , UBC (0.37) and BA ( 0 . 3 6 ) .  The s i r e and dam l i n e v a l u e s d e f i n i t e l y d i d n o t a g r e e . The r e p l i c a t i o n e f f e c t  on t h e 6-day embryo w e i g h t s was s i g n i f i c a n t  w i t h t h e mean v a l u e o f 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 cation 2,  respectively.  The a n a l y s e s o f v a r i a n c e o f body w e i g h t s presented i n Table 5.  I n g e n e r a l the s e c o n d o r d e r i n t e r a c t i o n s  s i g n i f i c a n t i n t h e 8 day embryos. i n t o the t e s t i n g  term.  embryonic a g e s .  terms were p o o l e d  T h e r e a f t e r no f i r s t o r d e r  sig-  interactions  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 o f t h e 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  a t 8 days o f i n c u b a t i o n . were s i g n i f i c a n t  The 3-way i n t e r a c t i o n  were n o t  There were 3 out o f 5 f i r s t o r d e r i n t e r a c t i o n s  n i f i c a n t a t 8 days o f i n c u b a t i o n . were s i g n i f i c a n t .  f r o m 8 t o 18 days o f age i s  The s e x e f f e c t  throughout  ception of replication  significant  starting  as w e l l as t h e r e p l i c a t i o n  effect  s t a r t i n g a t 8 days o f i n c u b a t i o n , w i t h t h e e x -  a t 12 and 14 days o f 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 o f v a r i a t i o n  d.f.  Sums o f s q u a r e s  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  1  0.0264*  S x R  3  0.0005  D x R  3  0.0031  Residual  9  0.0032  31  0.0687  Replication  (R)  Total  Significant  (P <_ 0 . 0 5 ) .  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 o f I n c u b a t i o n bource o r variation Sire l i n e (s)  d.f.  8  3  0.02  Dam l i n e (D)  3  S x D  9  12  10  0.16  * *  0.04 A 0.06  0.05 0.57  14  0.17 . A  2.49  0.72  0.96  0.56 A  A  1.06  5.35  A  2.72 A  18  16  12.44  11.00 A  2.73 A  23.74 14.97  A  Sex (F)  1  S x F  3  <0.01  <0.01  0.04  0.12  0.34  D xF  3  <0.01  0.02  0.04  0.33  . 0.61  1.86  S x D x F  9  0.03  0.40  1.05  2.56  1.56  R e p l i c a t i o n (R)  1  S x R  3  D x R  3  S x D x R  9  F  x R  1  S x  F  D x  F x R  x  R  Residual  Total  Significant  0.06  0.14  0.04  *  0.28  A  1.19  1.94  3.61  0.18  0.32  11.61  9.19  A  50.29  0.11  0.02  0.13  1.08  1.50  A  0.05  0.02  2.13  1.17  1.29  A  0.11  0.11  1.83  2.06  10.31  'A  <0.01  <0.01  0.02  0.11  1.72  0.14  0.13  0.09  2.14  0.43  0.05 0.04  3  0.01 <0.01  3  <0.01  0.05  0.10  0.23  0.65  6.07  9  <0.01  0.12  0.50  1.26  2.29  5.62  63  0.54  1.89  6.84  18.48  44.12  141.30  (P <_ 0 . 0 5 ) .  A  1. 75  * 0.03  A  A  - 30 -  t h a n f e m a l e s c o n s i s t e n t l y from 8 t o 18 days o f age ( T a b l e 6 ) . b a s i c agreement w i t h Deland ( 1 9 6 7 ) .  The mean body w e i g h t s i n r e p l i c a t i o n 2  were h i g h e r t h a n t h o s e i n r e p l i c a t i o n 1 w i t h t h e s i n g l e day embryo w e i g h t .  T h i s was i n  e x c e p t i o n o f t h e 14  Because o f t h e s e x 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 a n a l y s e a l l o f t h e subsequent d a t a based on s e p a r a t i o n o f t h e two s e x e s . The a n a l y s e s o f v a r i a n c e o f male embryo w e i g h t s i s shown i n T a b l e 7. Starting  a t 8 days o f age t h r o u g h 16 days t h e r e was a s i g n i f i c a n t dam l i n e  effect.  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 .  days o f age t h e r e was a r e p l i c a t i o n non-significant.  effect.  A t 8 days and 18  A l l 2-way i n t e r a c t i o n s were  The s i r e and dam l i n e means o f male embryo w e i g h t s i s p r e -  s e n t e d i n T a b l e 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 t h e s i r e l i n e s b u t f o r the dam l i n e s i t showed t h a t t h e male progeny o f t h e 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 At  from t h e o t h e r 3 l i n e s a t 8 and 10 days o f a g e .  12 days o f age t h e y had t h e l o w e s t a v e r a g e body w e i g h t , b u t t h i s was n o n -  significant BA.  from t h e NH and UBC l i n e s , b u t s i g n i f i c a n t l y d i f f e r e n t  A t 14 days o f age t h e 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  lines tested.  A t 16 days o f 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  and t h e NH b u t n o t s i g n i f i c a n t l y d i f f e r e n t  from t h e  from t h e 3 from t h e BA  f r o m t h e UBC l i n e , and t h e male  progeny o f t h i s l i n e s t i l l had t h e l o w e s t mean body w e i g h t among t h e 4 l i n e s . At 18 days o f age t h e male progeny o f t h e MH s t i l l had t h e l o w e s t mean, t h e v a l u e was n o t s i g n i f i c a n t l y d i f f e r e n t  from t h e o t h e r 3 l i n e s .  had c o n s i s t e n t l y t h e l o w e s t mean as a dam e f f e c t dam l i n e e f f e c t  The MH l i n e  and t h i s gave a c o n s i s t e n t  t o 16 days o f a g e . I t was o f extreme i n t e r e s t  t o observe  TABLE 6.  MEAN EMBRYO WEIGHTS OF MALES AND FEMALES BY REPLICATION  Mean embryo w e i g h t (gm.) Male Days o f incubation  Replication 1  Female Replication 2  Replication 1  Replication  Replication 2  Male  Female  1  2  0.39*  6  0.33  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*  25.01  27.11*  24.58  26.02  26.06  25.30*  24.79  26.56*  . 18  1  ^"6 day embryos n o t sexed.  *  S i g n i f i c a n t l y d i f f e r e n t between t h e 4 c a t e g o r i e s o f male , female, s e x 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 o f i n c u b a t i o n Source o f variation  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  9  0.03  0.18  0.39  1.63  1.80  6.74  31  0.23  0.90  3.08  10.01  23.95  72.66  Residual Total  *Significant  (P < 0.05).  TABLE 8.  SIRE AND DAM LINE MEAN EMBRYO WEIGHTS OF MALE PROGENY FROM 8 TO 18 DAYS OF INCUBATION  Mean embryo w e i g h t (gm.) Sire l i n e Days o f incubation  MH  BA  8  1.30  10  a  1.30  2.67  a  12  5.75  14  Dam l i n e  1  NH a  1.27  2.73  a  a  5.74  11.09  a  16  18.08  18  26.06  BA  UBC  MH  UBC  NH  1.35  3  1.20  b  1.30  3  1.30  2.82  a  2.54  b  2.76  a  2.76  a  6.10  a  5.49  b  5.82  ab  5.74  11.30  a  11.65  a  10.71  b  11.45  a  11.25  a  18.10  3  18.54  a  17.38  b  18.52  a  17.99  a  25.80  a  26.37  a  25.20  3  26.66  a  26.00  a  1.29  2.73  a  2.75  a  a  5.92  a  5.73  11.24  a  11.44  a  a  17.90  a  18.34  a  25.56  a  26.82  a  Those means w i t h i n t h e same row o f each s i r e o r dam l i n e which c a r r y t h e same s u p e r s c r i p t are n o t 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).  a  ab  3  ab  a  - 34 -  the v a l u e s i n the MH s i r e l i n e s i n c e t h e progeny were n o t c o n s i s t e n t l y t h e l o w e s t w e i g h t e d ( w i t h t h e e x c e p t i o n o f 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 a t 16 and 18 days o f a g e ) .  No s i g n i f i c a n t  d i f f e r e n c e was o b s e r v e d f o r any s i r e  l i n e e f f e c t t h r o u g h o u t t h e embryo age g r o u p s .  Therefore, the s i r e  means c o m p l e t e l y d i s a g r e e d w i t h t h e dam l i n e means f o r a l l ages The s i g n i f i c a n t  line  tested.  dam l i n e e f f e c t s m i g h t be due, a t l e a s t i n p a r t , t o  d i f f e r e n c e s i n egg component t r a i t s .  The means o f many egg component  t r a i t s f o r t h e 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 t h e p e r c e n t y o l k o f t h e MH l i n e was 27.20.  and d i f f e r e d line  I t was t h e l o w e s t  s i g n i f i c a n t l y f r o m t h e BA (29.78 p e r c e n t ) and t h a t o f t h e UBC  (28.75 p e r c e n t ) .  Similar results  These d i f f e r e n c e s i n egg components a l e n v i r o n m e n t s t o t h o s e embryos.  were o b s e r v e d f o r y o l k  solids.  should provide d i f f e r e n c e s i n n u t r i t i o n The s i r e l i n e s e f f e c t c o u l d be masked.  The a n a l y s e s o f v a r i a n c e of f e m a l e progeny ( T a b l e 9) showed a consistent significant  dam l i n e e f f e c t from 8 t o 18 days o f development  e x c e p t f o r 14 days o f a g e . T h i s was i n complete agreement w i t h t h e male progeny f o r a l l b u t t h e 14 days o f age a n a l y s i s .  The means o f t h e f e m a l e  progeny ( T a b l e 10) i n g e n e r a l , showed t h a t t h e progeny of t h e MH dam l i n e had t h e l o w e s t mean w h i c h was c o n s i s t e n t f o r a l l a g e s .  A t 8 days o f age  the progeny o f t h e 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 but  not s i g n i f i c a n t l y different  from t h e NH and the UBC l i n e .  o f 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 the  NH l i n e .  from t h e BA l i n e A t 10 days  from t h e BA and UBC l i n e b u t n o t f o r  A t 12 days o f 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 t h e 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 o f I n c u b a t i o n source or variation  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*  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  Residual  9  0.02  0.06  0.22  1.46  2.55  9.19  31  0.25  0.84  2.56  6.53  16.56  59.45  Total  * S i g n i f l e a n t (P _< 0 . 0 5 ) .  16.04*  TABLE 10. SIRE AND DAM LINE MEAN EMBRYO WEIGHTS OF FEMALE PROGENY FROM 8 TO 18 DAYS OF INCUBATION  Mean embryo w e i g h t  (gm.) Dam l i n e  Sire l i n e 1 Days o f incubation  BA  MH  NH  UBC  BA  MH  NH  UBC  8  1.27 a  1.20 a  1.21 3  1.23 a  1.29 3  1.16 b  1.22 a b  1.25ab  10  2.58 a  2.62 a  2.67 a  2.64 a  2.74 a  2.50 b  2.61ab  2.66 a  12  5.41a  5.44 a  5.70 3  5.513  5.80 a  5.30 b  5.53ab  5.43 b  14  10.85a  10.76 a  ll.ll  10.95 3  11.16 3  10.59 3  11.12 a  10.813  16  17.57 3  17.533  17.64 3  17.78 a  17.73 b  16.97 C  18.17 3  17.65 b  18  24.99 a  24.80 3  25.83a  25.58 a  25.36 a  24.13 b  25.92 a  25.79 a  a  Those means w i t h i n t h e same row o f each s i r e o r dam l i n e which c a r r y the same s u p e r s c r i p t a r e n o t s i g n i f i c a n t l y d i f f e r e n t (P > 0 . 0 5 ) .  - 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 A t 14 days o f a g e , i n t e r e s t i n g l y  from t h e NH. l i n e o r t h e UBC l i n e .  enough, a l t h o u g h i t had t h e l o w e s t mean  the MH dam l i n e e f f e c t was n o t s i g n i f i c a n t l y d i f f e r e n t  among any o f t h e  l i n e s f o r the female p r o g e n y , b u t a t 16 days o f age i t was s i g n i f i c a n t l y different  from t h e o t h e r 3 l i n e s .  I n a d d i t i o n a t t h a t t i m e , t h e 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  f r o m t h e NH l i n e .  A g a i n , a t 18  days o f age t h e f e m a l e progeny o f t h e 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 t h e o t h e r 3 l i n e s w h i c h were n o t s i g n i f i c a n t l y d i f f e r e n t each o t h e r .  from  T h e r e f o r e , t h e dam e f f e c t o b s e r v e d from 8 t o 18 days o f age  was a p r i n c i p a l c o n t r i b u t i o n o f t h e "MH l i n e .  As w i t h t h e m a l e p r o g e n y ,  comparing t h e s i r e l i n e means t h e r e 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. the  However, t h e progeny o f t h e MH l i n e had  l o w e s t averaged body w e i g h t a t 8 , 1 4 , 16 and 18 days o f a g e , a l t h o u g h  t h e s e d i f f e r e n c e s were n o t s i g n i f i c a n t .  T o r t h e female progeny t h e body  w e i g h t means o f t h e MH s i r e and dam l i n e s were i n agreement a s c o n t r a s t e d t o the male progeny where no such agreement c o u l d be n o t e d . Significant  r e p l i c a t i o n e f f e c t s were found f o r t h e m a l e progeny a t  8 and 18 days o f a g e , b u t 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 c a t i o n f o r t h e f e m a l e progeny was f o u n d . T a b l e 6.  to r e p l i -  The r e p l i c a t i o n means a r e shown i n  The a v e r a g e body w e i g h t o f a l l male progeny i n r e p l i c a t i o n 2 were  consistently  h i g h e r t h a n t h o s e o f t h e male progeny i n r e p l i c a t i o n 1.  d i f f e r e n c e was s i g n i f i c a n t a t 8 and 18 days o f development.  This  Although there  was no s i g n i f i c a n t e f f e c t o f r e p l i c a t i o n f o r female p r o g e n y , t h e comparison o f t h e female body w e i g h t s i n d i c a t e d t h a t t h e females o f r e p l i c a t i o n 2 were  - 38 -  h e a v i e r than those o f t h e females o f r e p l i c a t i o n  1 w i t h the exception of  14 days o f age where t h e d i f f e r e n c e was one t e n t h o f a gram i n f a v o u r o f the  female progeny o f r e p l i c a t i o n  i t i s not consistently ence i n t h i s  1.  T h e r e f o r e , i t w o u l d appear a l t h o u g h  s i g n i f i c a n t t h e r e was a d e f i n i t e r e p l i c a t i o n  differ-  study.  Embryo Growth Rates The mean embryo growth r a t e s f o r each s e x and g e n o t y p i c m a t i n g r e c o r d e d a t 2-day i n t e r v a l s  f r o m 6 t o 18 days o f i n c u b a t i o n a r e shown i n T a b l e  11 and t h e a n a l y s e s o f t h e s e embryo growth r a t e s i s p r e s e n t e d i n T a b l e 1 2 . I n g e n e r a l , t h e 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 t h e e x c e p t i o n  o f t h e s i r e x dam x s e x i n t e r a c t i o n 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 the  o f 6-8 day embryo growth r a t e and t h e o f t h e same growth p e r i o d .  In contrast,  16-18 day embryo growth r a t e h a d t h e r e m a i n i n g 3-way i n t e r a c t i o n s  n i f i c a n t ; the s i r e x s e x x r e p l i c a t i o n S i n c e none o f t h e 3-way i n t e r a c t i o n s  sig-  and t h e dam x s e x x r e p l i c a t i o n .  were s i g n i f i c a n t i n t h e r e m a i n i n g growth  p e r i o d s and s i n c e t h e r e was no c o n s i s t e n c y i n t h e 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 t h a t t h e s e s i g n i f i c a n t i n t e r a c t i o n s logically significant. 2-way i n t e r a c t i o n s  A pooled t e s t i n g  term was used t o t e s t f o r t h e  as w e l l as some o f t h e main e f f e c t s .  36 f i r s t o r d e r i n t e r a c t i o n s  were n o t b i o -  were s i g n i f i c a n t .  Only 4 out o f  Those f i r s t o r d e r  interactions  w h i c h were s i g n i f i c a n t were a l s o i g n o r e d and p o o l e d i n t h e e r r o r t e r m . sire line effect  The  on t h e embryo growth r a t e s was observed t o be s i g n i f i c a n t  o n l y f o r t h e 8-10 day embryo growth r a t e . e f f e c t s were s i g n i f i c a n t  The dam l i n e and t h e r e p l i c a t i o n  f o r t h e 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  Sire BA Dam line  BA  MH  NH  UBC  MH  NH  M  M  line UBC  M  Mean  M  M  6-8 8-10 10-12 12-14 14-16 16-18  4.40 3.20 4.22 4.10 3.64 2.91  4.34 3.02 4.20 4.36 3.66 2.62  4.33 3.24 4.19 4.32 3.28 3.00  3.99 3.70 3.84 4.42 3.28 3.00  3.93 3.40 4.58 3.80 3.60 3.02  3.82 3.40 4.40 3.86 3.44 3.28  3.98 3.38 3.85 4.62 3.40 3.04  3.83 3.36 4.04 4.36 3.50 3.22  4.16 3.31 4.21 4.21 3.48 2.99  4.00 3.37 4.12 4.25 3.47 3.03  6-8 8-10 10-12 12-14 14-16 16-18  4.57 3.28 4.38 4.20 3.55 3.39  4.74 3.01 4.28 4.63 3.30 3.09  4.54 3.41 4.02 4.66 3.62 2.70  4.28 3.70 4.06 4.19 3.86 2.68  4.44 3.41 4.30 4.23 3.63 3.44  4.01 3.90 4.14 4.41 3.38 3.20  4.58 3.36 4.20 4.24 3.71 3.08  4.59 3.21 4.02 4.70 3.58 2.97  4.53 3.36 4.22 4.33 3.63 3.15  4.40 3.45 4.12 4.48 3.53 2.99  6-8 8-10 10-12 12-14 14-16 16-18  4.55 3.30 4.10 4.28 3.77 3.01  4.30 3.36 3.82 4.68 3.88 2.76  4.48 3.34 4.30 4.14 3.66 3.16  4.18 3.30 4.34 4.63 3.71 3.08  4.36 3.36 4.12 4.55 3.50 3.36  4.15 3.61 4.06 4.58 3.50 3.18  4.42 3.43 3.93 4.57 3.46 2.81  4.26 3.39 4.25 .4.25 3.64 3.00  4.45 3.36 4.11 4.39 3.60 3.08  4.22 3.42 4.12 4.54 3.68 3.01  6-8 8-10 10-12 12-14 14-16 16-18  4.47 3.12 4.14 4.44 3.69 3.07  4.28 3.25 4.00 4.38 3.58 3.46  4. 73 3. 38 3. 79 4.32 3. 39 3. 22  4.54 3.36 3.78 4.46 3.82 2.98  4.59 3.54 3.98 4.54 3.42 3.08  4.64 3.25 4.02 4.50 3.50 3.30  4.42 3.44 4.16 4.15 3.55 3.10  4.14 3.64 3.88 4.52 3.80 3.14  4.55 3.37 4.02 4.36 3.51 3.12  4.40 3.40 3.92 4.46 3.68 3.21  -8 i-10 '-12 -14 -16 -18  4.50 3.22 4.21 4.26 3.66 3.10  4.42 3.16 4.07 4.51 3.60 2.98  4.52 3.34 4.08 4.36 3.49 3.02  4.25 3.52 4.00 4.42 3.66 2.94  4.33 3.43 4.24 4.28 3.54 3.22  4.16 3.56 4.16 4.34 3.45 3.24  4.35 3.40 4.04 4.39 3.53 3.01  4.20 3.40 4.05 4.46 3.63 3.08  4.42 3.35 4.14 4.32 3.55 3.09  4.26 3.41 4.07 4.43 3.59 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  P e r i o d o f growth (day) Source o f variation  d.f  6-8  S i r e l i n e (S)  3  0.46  Dam l i n e (D)  3  S x D  9  Sex (F)  1  S x F  3  0.45 0.08  D x F  3  0.02  12-14  14-16  16-18  0.82  0.29  0.12  0.16  0.58  0.04  0.43  0.50  0.24  * ft  1.65  10-12  8-10  ft  1.06 ft  ft  0.22 ft  0.48  1.08  1.09  0.73  1.20  0.06  0.08  0.19  0.02  0.01  0.14  0.04  0.11  0.18  0.09  <0.01  0.03  0.03  0.16  0.16  0.62  0.39  1.11  0.18  S x D x F  9  R e p l i c a t i o n (R)  1  2.32  <0.01  0.44  0.68  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  0.46  0.66  0.77  0.89  F  x R  0.26  ft  ft 0.92  0.80  ft  *  0.47 ft  *  1  0.08  0.25  <0.01  <0.01  0.05  0.06  S x F  xR  3  0.01  0.27  0.65  0.27  0.40  D x F  x R  3  . 0.09  0.52  0.13  0.04  0.20  9  0.07  0.42  1.11  1.64  1.08  0.68* * 1.00 0.51  63  7.66  4.76  6.08  7.49  9.80  7.58  Residual  Total  Significant  ( P < 0.05).  - 41 -  e f f e c t was s i g n i f i c a n t a g a i n f o r t h e 14—16 and 16^3.8 day embryo growth rate.  I n c o n t r a s t t o t h a t o b s e r v e d f o r body w e i g h t s t h e o n 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 o f t h e 2 sexes o c c u r r e d i n t h e 6^-8 day embryo growth r a t e .  T h i s would i n d i c a t e t h a t t h e body w e i g h t d i f f e r e n c e s o b s e r v e d  i n t h e males and f e m a l e s o f embryos o f 8 , 1 0 , 1 2 , 1 4 , 16 and 18 days o f 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 o f embryonic a g e .  I n a d d i t i o n , one s h o u l d remember t h a t sex a t 6 days o f age  was n o t r e c o r d e d .  T h e r e f o r e , body w e i g h t d i f f e r e n c e s a t 8 days o f age f o r  e a c h s e x c o n c e i v a b l y would e x i s t a t 6 days o f i n c u b a t i o n o r e a r l i e r . The means o f embryo g r o w t h r a t e s showing t h e d i f f e r e n c e s between the 13.  2 s e x e s , as w e l l as t h a t between t h e 2 r e p l i c a t i o n s  a r e shown i n T a b l e  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 i g h e r t h a n t h a t o f r e p l i c a t i o n 2.  However, t h e 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 l o w e r t h a n 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 t h e body w e i g h t a n a l y s e s t h e growth r a t e s were  a n a l y z e d s e p a r a t e l y f o r male and female p r o g e n y .  The a n a l y s e s o f v a r i a n c e  o f mean embryo growth r a t e s o f males w i t h t h e p o o l e d 3-way i n t e r a c t i o n s a r e p r e s e n t e d i n T a b l e 1 4 . The o n l y 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 m e a s u r a b l e i n t h e 6-8 day embryo growth r a t e was t h a t o f t h e dam l i n e and t h a t o f t h e r e p l i c a t i o n e f f e c t . a significant sire effect.  effect  The 8-10 day embryo growth r a t e showed  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 p r e s e n t i n  the l a t e r growth s t a g e s , except f o r t h e s i g n i f i c a n t e f f e c t o f t h e s i r e x  TABLE  13. MEAN EMBRYO GROWTH RATES OF MALES AND FEMALES BY REPLICATION  Mean growth r a t e Period of growcn (day)  Male Replication 1  Female Replication 2  Replication 1  Replication  Replication 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 n o t s e x e d . 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 . 0 5 ) .  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  P e r i o d o f growth (day) Source o f variation  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. 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  31  2. 70  1.26  2.79  3.71  5.18  3.91  Total  *Significant  (P <_ 0 . 0 5 ) .  - 44 -  replication interaction  a t 16-18 day embryo growth, r a t e .  The s i r e and dam  l i n e mean embryo g r o w t h r a t e s o f -males i n T a b l e 15 i n d i c a t e d t h a t t h e s i g n i f i c a n t dam l i n e e f f e c t o f t h e male progeny was a t t r i b u t a b l e  t o t h e BA  l i n e w h i c h had t h e l o w e s t 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 NH and t h e UBC l i n e , w h i c h were n o t s i g n i f i c a n t l y d i f f e r e n t 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  from t h e MH,  from each o t h e r .  o b s e r v e d i n t h e 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  t o t h e l o w e r growth r a t e o f t h e BA l i n e .  significantly different  from t h e r e s t o f t h e 3 l i n e s w h i c h were n o t s i g n i f i -  cantly different  from each o t h e r .  i n embryonic growth r a t e f o r e i t h e r  I t was  There were no o t h e r s i g n i f i c a n t  differences  s i r e o r dam l i n e f o r male progeny  there-  after. The a n a l y s e s o f t h e f e m a l e progeny ( T a b l e 16) i n c o n t r a s t t o t h a t o f 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 t h e s i r e o r 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  significant  e f f e c t measurable was t h a t o f r e p l i c a t i o n , and i t was o b s e r v a b l e i n t h e 6-8 day embryo growth r a t e .  I t i s interesting  t o n o t e , however, a l t h o u g h t h e y  were n o t s i g n i f i c a n t , t h e growth r a t e comparisons averaged i n t h e s i r e and dam l i n e s ( T a b l e 17) showed t h e female progeny o f the BA dam l i n e had t h e l o w e s t 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 t h e 8-10  day embryo growth r a t e w h e r e , a g a i n , t h e progeny o f t h e BA s i r e s had t h e l o w e s t growth r a t e . T h i s c o r r e s p o n d e d t o t h e same s i r e e f f e c t  observed i n the  male progeny i n the p r e v i o u s 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 n l y f o r t h e 6-8 day embryo growth r a t e .  This result  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 r a t e 1 Sire l i n e  P e r i o d of growth (day)  NH  Dam l i n e BA  BA  MH •  6-8  4.50a  4.52 a  4.33a  4.35 a  4.16 b  4.53 a  4.45 a  4.55a  8-10  3.22 b  3.34 a  3.43 a  3.40 3  3.31 a  3.36 a  3.36 a  3.37 a  10-12  4.21a  4.08 a  4.24 a  4.04 a  4.21 a  4.22 a  4.11a  4.02a  12-14  4.26 a  4.36 a  4.28 a  4.39 a  4.21 a  4.33 a  4.39 a  4.36 a  14-16  3.66 a  3.49 a  3.54 a  3.53 a  3.48 a  3.63 a  3.60 a  3.51 3  16-18  3.10 a  3.02 a  3.22 a  3.0la  2.99 a  3.15 3  3.08 3  3.12 a  UBC  MH  NH  UBC  Those means w i t h i n t h e same row o f each s i r e o f dam l i n e which c a r r y t h e same s u p e r s c r i p t are n o t s i g n i f i c a n t l y d i f f e r e n t (P > 0 . 0 5 ) .  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  Sire l i n e (S)  3  0.31  0.76  0.10  0.13  0.21  0.43  Dam l i n e (D)  3  0.88  0.03  0.24  0.38  0.27  0.27  S xD  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 xR  3  0.11  0.11  0.89  0.11  0.17  0.09  D xR  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  31  4.51  3.45  3.21  3.58  4.60  3.66  Total  Significant  (P_<0.05).  14-16  16-18  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 r a t e Sire line P e r i o d of growth (day)  BA  MH  Dam NH  UBC  BA  MH  line NH  UBC  6-8  4.42 a  4.253  4.16 a  4.20 3  4.00 a  4.40 3  4.22 a  4.403  8-10  3.16 a  3.52 a  3.56 a  3.40 a  3.37 a  3.45 a  3.42 a  3.40 a  10-12  4.07 3  4.00a  4.16 a  4.05 3  4.12 a  4.12 a  4.12 a  3.92 a  12-14  4.51 a  4.42 a  4.34 a  4.46 a  4.25 a  4.48 a  4.54 a  4.46 a  14-16  3.61 3  3.66 a  3.45 a  3.63 a  3.47 a  3.53 a  3.68 a  3.68 a  16-18  2.98 a  2.94 a  3.24 a  3.08 a  3.03 3  2.99 a  3.01 a  3.22 a  'Those means w i t h i n t h e same row o f each s i r e o r dam l i n e which c a r r y t h e 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 . 0 5 ) .  - 48 -  The mean growth r a t e o f b o t h r e p l i c a t i o n s 13.  f o r e a c h sex i s shown i n T a b l e  The 6-8 day embryo g r o w t h r a t e o f 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  l o w e r t h a n 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 f e m a l e s .  The d i f f e r -  ences o f mean growth r a t e s among a l l t h e r e s t o f t h e growth p e r i o d s were non-significant.  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 d e m o n s t r a t e d .  Averaged Embryo Growth R a t e s The growth r a t e s o f embryos f o r v a r y i n g p e r i o d s o f time i s shown i n the A p p e n d i x T a b l e 2 .  The 2 day growth r a t e e s t i m a t e s f o r t h e d i f f e r e n t i n -  t e r v a l s o f i n c u b a t i o n were averaged t o p r o v i d e e s t i m a t e s f o r t h e p e r i o d s b e g i n n i n g a t 8 and e n d i n g a t 1 2 , 1 4 , 16 and 18 days o f i n c u b a t i o n , a s w e l l a s t h o s e f o r o t h e r s i m i l a r comparisons s t a r t i n g a t 1 0 , 12 and 14 days o f a g e . The a n a l y s e s o f v a r i a n c e o f t h e s e averaged growth r a t e e s t i m a t e s a r e shown i n T a b l e 1 8 . No second o r d e r i n t e r a c t i o n was s i g n i f i c a n t .  O n l y t h e 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 . period.  The s i r e l i n e e f f e c t was n o t s i g n i f i c a n t f o r any growth  C o n t r a r i l y , t h e 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 t h e growth  p e r i o d s s t u d i e d , w i t h t h e e x c e p t i o n o f t h e 8-12, 10-14, 10-18 and 14-18 day embryo growth r a t e s .  No s e x d i f f e r e n c e s were s i g n i f i c a n t .  e f f e c t s were s i g n i f i c a n t f o r most o f t h e growth p e r i o d s .  The r e p l i c a t i o n I t can be assumed  t h a t t h e r e 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  t h e growth  and t h e subsequent body w e i g h t s o f t h e embryos. The mean averaged embryo growth r a t e s a r e shown i n T a b l e 1 9 . The i n c o n s i s t e n c y o f h i g h e r and l o w e r mean embryo growth r a t e s between t h e 2 sexes and between t h e 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 t o 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  P e r i o d ' o f growth (day) Source o f variation  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 xF  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 xF  9  0.13  0.06  0.03  <0.01  0.17  0.08  0.02  0.23  0.04  o.ii  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  1  0.04  0.02  <0.01  <0.01  <0.01  0.01  0.02  0.01  0.02  0.06  x R  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  9  0.16  0.07  0.03  0.03  0.17  0.15  0.09  0.29  0.12  0.36  63  1.77  0.85  0.51  0.46  1.85  0.82  0.77  2.09  1.29  3.44  Residual  Total  ft S i g n i f i c a n t (P _< 0 . 0 5 ) .  TABLE 19.  MEAN EMBRYO GROWTH RATES OF MALES AND FEMALES BY REPLICATION  Mean growth r a t e Period o f growth (day)  Female  Male Replication 1  Replication 2  Replication 1  Replication Replication 2  Male  Female  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 t h e 4 c a t e g o r i e s o f male, f e m a l e , s e x and r e p l i c a t i o n (P <_ 0.05).  - 51 -  meaningful conclusion.  The a n a l y s e s o f v a r i a n c e o f t h e male embryo growth  r a t e s ( T a b l e 20) showed t h a t t h e s i g n i f i c a n t  dam l i n e e f f e c t s were t h e  a v e r a g e d g r o w t h r a t e s from t h e 8—16 and 8-18 day embryo growth r a t e s . comparable e f f e c t was n o t s i g n i f i c a n t e f f e c t was s i g n i f i c a n t growth r a t e s .  f o r the s i r e l i n e .  The  The  replication  i n t h e 8-14, 8-18, 10-14, 10-18 and 14-18 day embryo  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  effect.  The  absence o f 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 m a t e r n a l e f f e c t n o t e d i n t h e p r e v i o u s body w e i g h t a n a l y s i s was n o t m e a s u r a b l e i n t h e comparable g r o w t h 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 p e r i o d s o f time averaged f o r t h e s i r e and dam l i n e s f o r t h e male progeny a r e p r e s e n t e d i n T a b l e 2 1 . P r e d i c a t e d on t h e s i r e l i n e s were no s i g n i f i c a n t  there  d i f f e r e n c e s among t h e 4 l i n e s f o r a l l growth p e r i o d s  s t u d i e d w i t h the e x c e p t i o n o f t h e 8-18 day embryo growth r a t e i n w h i c h t h e mean growth r a t e o f the MH and t h e UBC were n o t s i g n i f i c a n t l y d i f f e r e n t b u t t h e y were s i g n i f i c a n t l y l o w e r t h a n the NH l i n e .  The mean growth r a t e o f t h e  BA was n o t s i g n i f i c a n t l y d i f f e r e n t  from t h e r e s t .  f o r t h e dam l i n e s , t h e same r e s u l t s  were o b t a i n e d w i t h t h e e x c e p t i o n o f t h e  8-10 and 8-18 day embryo growth r a t e s .  On t h e averaged v a l u e s  A t 8-16 day embryo growth r a t e t h e  mean growth r a t e o f t h e BA and t h e UBC were n o t s i g n i f i c a n t l y d i f f e r e n t , b u t they were s i g n i f i c a n t l y l o w e r t h a n t h e MH.  The mean embryo growth r a t e o f  the NH l i n e was n o t s i g n i f i c a n t l y d i f f e r e n t  from t h e o t h e r 3 l i n e s .  8-18 day embryo growth r a t e o f t h e BA l i n e was n o t s i g n i f i c a n t l y  The mean  different  from t h e UBC l i n e b u t i t was s i g n i f i c a n t l y l o w e r than t h o s e o f t h e MH and t h e  TABLE 20.  SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN MALE EMBRYO GROWTH RATES FOR VARYING GROWTH PERIODS  P e r i o d o f growth I(day) Source o f variation  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  0.09  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 xD  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  31  0. 78  0 .40  0 .19  0.20  0 .70  0. 43  0.46  1.02  0. 70  2.08  Total  Significant  (P <_ 0 . 0 5 ) .  TABLE 2 1 .  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 r a t e 1 Sire l i n e  P e r i o d of growth (day)  BA  MH  8-12  3.72 a  3.71 a  8-14  3.89 a  8-16  Dam l i n e UBC  BA  MH  3.84 a  3.72 a  3.76 a  3.80 3  3.74 a  3.69 a  3.93 a  3.98 a  3.94 a  3.91 a  3.97 a  3.95 a  3.92 a  3.84 a  3.82 a  3.87 a  3.84 a  3.80 b  3.89 a  3.86ab  3.82 b  8-18  3.69ab  3.66 b  3.74 a  3.68 b  3.64 C  3.74 a  3.71ab  3.68bc  10-14  4.23a  4.22a  4.26 a  4.22 a  4.21a  4.28 a  4.25a  4.19 a  10-16  4.04 a  3.98 a  4.02 a  3.99 a  3.97 a  4.06 a  4.03 a  3.96 a  10-18  3.74 a  3.82 a  3.74 a  3.72 a  3.83 a  3.80 a  3.75 a  12-16  3.81 a a 3.96  3.92 a  3.91 a  3.96 a  3.84 a  3.98 a  3.99 a  3.94 a  12-18  3.67 a  3.62 a  3;68 a  3.64 a  3.56 a  3.70 a  3.69 a  3.66 a  14-18  3.38 a  3.25 a  3.38 a  3.27 a  3.23 a  3.39 a  3.34 a  3.32 a  NH  NH  "'"Those means w i t h i n t h e same row o f each s i r e or dam l i n e which c a r r y t h e same s u p e r s c r i p t are n o t s i g n i f i c a n t l y d i f f e r e n t (P > 0 . 0 5 ) .  UBC  - 54 -  NH l i n e .  The mean embryo g r o w t h r a t e o f t h e UBC l i n e was s i g n i f i c a n t l y  l o w e r t h a n t h e "MH l i n e b u t was n o t s i g n i f i c a n t l y d i f f e r e n t  from t h e NH l i n e ,  and the mean o f t h e MH and t h e NH l i n e were n o t s i g n i f i c a n t l y  different.  The f e m a l e progeny's a n a l y s e s o f v a r i a n c e a r e p r e s e n t e d i n T a b l e 2 2 . In c o n t r a s t t o t h e male p r o g e n y , the f e m a l e progeny had some interaction not  effects.  significant  However, t h e y appeared t o be q u i t e s p o r a d i c and were  c o n s i s t e n t throughout t h e d a t a .  f i c a n t , and s i r e x dam i n t e r a c t i o n  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 -  was a l s o n o n - s i g n i f i c a n t .  T a b l e 23 shows  the mean a v e r a g e d female g r o w t h r a t e s based on t h e s i r e and dam l i n e s . m e n t i o n e d p r e v i o u s l y , t h e r e was no s i g n i f i c a n t 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 .  As  d i f f e r e n c e among t h e s i r e  I n t h e c a s e o f t h e dam l i n e s , i n  g e n e r a l , t h e MH l i n e had t h e h i g h e s t mean growth r a t e s , w h i l e t h e BA l i n e had t h e l o w e s t mean growth r a t e . f e r e n c e s c o u l d be f o u n d .  However, o n l y s p o r a d i c s i g n i f i c a n t  There was no s i g n i f i c a n t  dif-  d i f f e r e n c e among t h e s i r e  l i n e s f o r a l l p e r i o d s o f growth s t u d i e d o f f e m a l e progeny  ( T a b l e 2 2 ) . The  a v e r a g e d 8-12 and 8-10 day embryo growth r a t e s f o r t h e dam l i n e s were n o t significantly different.  The 8-16 day embryo growth r a t e o f the BA l i n e  was n o t s i g n i f i c a n t l y d i f f e r e n t  from t h e UBC l i n e b u t i t was s i g n i f i c a n t l y  lower t h a n t h e MH and NH l i n e .  W h i l e t h e mean growth r a t e s o f t h e MH, NH  and UBC l i n e were n o t 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 o f t h e 4 l i n e s were n o t s i g n i f i c a n t l y d i f f e r e n t the  until  12-18 day embryo growth r a t e i n w h i c h t h e mean growth r a t e o f t h e MH,  NH, and UBC l i n e s were n o t s i g n i f i c a n t l y d i f f e r e n t , b u t t h e means o f t h e NH and UBC l i n e s were s i g n i f i c a n t l y h i g h e r than t h e BA l i n e .  The 14-18 day  TABLE 2 2 .  SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MEAN FEMALE EMBRYO GROWTH RATES FOR VARYING GROWTH PERIODS  P e r i o d o f growth(day) bource o r variation  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 xD  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  31  0.,99  0 .43  0..31  0. 25  1.14  0. 38  0. 32  0. 98  0. 56  1.35  Total  Significant  (P <_ 0 . 0 5 ) .  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 r a t e Dam l i n e  Sire l i n e 1 P e r i o d of growth (day)  BA  MH  NH  UBC  BA  MH  NH  UBC '  8-12  3.62 a  3.76 a  3.86 a  3.72 a  3.74 a  3.79 a  3.76 a  3.66 a  8-14  3.92 a  3.98 a  4.02a  3.97 a  3.91 a  4.02 a  4.02a  3.93 a  8-16  3.84 a  3.90 a  3.88 a  3.88 a  3.80 b  3.90 a  3.94 a  3.86ab  8-18  3.67 a  3.71 a  3.75 a  3.72 a  3.65 a  3.72 a  3.75 a  3.74 a  10-14  4.29a  4.21a  4.24 a  4.25a  4.18 a  4.30 a  4.32a  4.19 a  10-16  4.06a  4.033  3.98 a  4.05 a  3.95 a  4.05 a  4.11a  4.02a  10-18  3.79 a  3.76 a  3.80 a  3.81 a  3.72 a  3.78 a  3.84 a  3.82 a  12-16  4.06 a  4.04 a  3.90 a  4.04 3  3.86 a  4.01a  4.11a  4.07 a  12-18  3.70 3  3.68 a  3.68 a  3.72 a  3.58 b  3.67ab  3.74 a  3.78 a  14-18  3.30 a  3.30 a  3.35 a  3.36 a  3.25 b  3.26 b  3.34ab  3.45 a  Those means w i t h i n the same row o f each s i r e o r dam l i n e which c a r r y the same s u p e r s c r i p t a r e n o t s i g n i f i c a n t l y d i f f e r e n t (P > 0 . 0 5 ) .  - 57 -  embryo growth, r a t e t h e dam l i n e means o f t h e BA, Jffl. and NH, were n o t s i g n i f i c a n t l y d i f f e r e n t , b u t t h e mean growth r a t e o f the BA and'MH l i n e were cantly  signifi-  l o w e r t h a n t h a t o f t h e UBC l i n e w h i c h was n o t s i g n i f i c a n t l y d i f f e r e n t  from t h e NH l i n e . C h i c k Body Weights The number o f progeny e v a l u a t e d i n t h e p o s t embryonic d a t a f o r each d i a l l e l m a t i n g c e l l , s e x and r e p l i c a t i o n i s p r e s e n t e d i n A p p e n d i x T a b l e 4 . T h e r e were 1,468 i n d i v i d u a l s i n t h e f i r s t and 1,533 i n d i v i d u a l s i n t h e s e cond r e p l i c a t i o n w h i c h gave a t o t a l o f 3,001 progeny f o r t h e e x p e r i m e n t . The s e x r a t i o was v e r y c l o s e t o 50:50.  The average number o f t h e progeny  used i n each s u b c l a s s was 4 6 , b u t ranged from 31 t o 59 i n d i v i d u a l s .  The  average c h i c k body w e i g h t s a t w e e k l y i n t e r v a l s from h a t c h t o 7 weeks o f age i s p r e s e n t e d i n T a b l e 2 4 . The BA l i n e had t h e l o w e s t a v e r a g e d h a t c h i n g w e i g h t f o r males  (37 grams) and f e m a l e s (36 g r a m s ) .  The MH l i n e had t h e  h i g h e s t averaged male (41 grams) and female (40 grams) h a t c h i n g v a l u e s . However, a t 7 weeks o f age t h e NH l i n e had t h e h i g h e s t a v e r a g e d body w e i g h t o f 885 grams and 718 grams f o r males and f e m a l e s , r e s p e c t i v e l y .  The MH l i n e  had t h e l o w e s t average body w e i g h t o f 745 grams and 614 grams f o r males and females,  respectively. The a n a l y s e s o f v a r i a n c e o f t h e mean body w e i g h t s a r e shown i n  T a b l e 2 5 . No s i g n i f i c a n t e f f e c t o f any second o r d e r i n t e r a c t i o n s  i n body  w e i g h t s were o b s e r v e d , and t h e s o u r c e s o f v a r i a t i o n were p o o l e d 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 t h e w e e k l y  - 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 l i n e Dam line  BA  MH  NH  UBC  Mean  BA  MH  UBC  NH M  F  M  F  Mean F M  Week  M  F  M  F  H 1 2 3 4 5 6 7  37 64 134 222 340 478 630 776  36 64 126 206 305 420 540 656  39 74 150 248 372 514 669 819  38 71 138 218 315 426 540 651  36 71 148 252 386 541 708 880  35 66 134 222 331 455 582 712  38 72 152 252 383 535 698 857  37 70 140 226 330 448 565 683  37 70 146 244 370 517 676 833  36 68 135 218 320 437 557 675  H 1 2 3 4 5 6 7  40 72 147 244 368 514 666 819  40 68 134 216 316 431 548 662  41 72 143 232 342 472 608 745  40 72 138 216 307 414 518 614  40 74 150 248 370 512 663 815  39 74 144 230 334 452 572 684  41 74 149 246 368 508 660 814  40 72 143 226 328 440 554 666  40 73 147 243 362 501 649 798  40 71 140 222 321 434 548 656  H 1 2 3 4 5 6 7  38 74 150 257 391 552 722 882  38 68 134 224 336 467 602 732  39 74 152 253 380 530 692 856  38 72 141 228 335 459 581 701  39 70 . 145 246 377 536 710 885  39 66 133 220 328 454 588 718  40 74 154 262 396 556 730 902  40 72 144 234 348 472 602 723  39 73 150 254 386 544 714 881  39 69 138 226 337 463 593 719  H 1 2 3 4 5 6 7  40 70 147 246 372 520 684 839  39 68 136 217 320 438 564 682  41 74 148 240 356 490 636 778  40 72 139 217 312 421 530 637  40 74 152 254 386 540 711 881  39 70 141 228 336 459 588 715  40 70 145 239 362 504 660 818  39 68 134 216 317 434 551 660  40 72 148 245 369 514 673 829  39 69 137 220 322 438 558 674  H 1 2 3 4 5 6 7  39 70 144 242 368 516 676 829  38 67 133 215 319 439 563 683  40 74 148 243 362 501 651 799  39 72 139 220 317 430 542 651  38 72 149 250 380 532 698 865  38 69 138 225 332 455 583 707  40 73 150 250 377 526 687 848  39 70 140 226 331 448 568 683  39 72 148 246 372 519 678 835  38 69 137 221 325 443 564 681  TABLE  2 5 . 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 o f w e i g h i n g (week) s o u r c e or variation  d.f.  Hatch  S i r e l i n e (S)  3  17.42  Dam l i n e (D)  3  S x D  9  * * 97.55 11.52  2  1 142.67 73.67  * *  ft 153.77  Sex ( F )  1  6.89  112.89  S x F.  3  .30  4.67  D x F  3  .92  9.17  S x D xF  9  .64  26.02  R e p l i c a t i o n (R)  1  395.02*  S x R  3  1.17 ft  ft  3  4  5  6 16,147*  31,117  25,706*  44,114*  7,712  11,206*  16,813*  91,658*  207,370*  381,150*  383.63  993.05  2,939.20  7,136  146.38  942.67  3,734.40  11,412  728.00*  2,161.80*  9,925.10* 35,016.00*  1,743.10* 18.31 ft 50.31 79.31  4,512.00*  ft  28.92  29.05  99  117.80  213.30  478  277.39  556.14  5,365.60* 6,460.10* 11,263.00* ft 15.92 82.17 143.05 55.06 ft 94.06* 125.55 175.55 45.67  1,711.90*  7  251  ft  919 *  904  1,173  967 1,915  2,399  9,168  36,912*  1,860  244  532  1,059  159  386  53  D x R  3  5.55  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  x R  3  .55  5.55  15.88  45.67  76.42  58  83  189  R  3  2.42  4.80  11.62  19.80  67.92  68  113  210  9  3.64  12.89  28.50  150.39  245.77  582  839  1,368  63  553.73  2,358.40  8,783.00  21,436.00  59,155.00  130,320  303,290  483,290  S x F D x F  x  Residual  Total  *Significant  (P <. 0 . 0 5 ) .  - 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 a t 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 a t 2 weeks and t h e 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 t h e f i r s t 3 weeks o f t h e study.  These s i g n i f i c a n t e f f e c t s o f t h e f i r s t o r d e r i n t e r a c t i o n s  indicated  t h a t i t would be a d v i s a b l e t o a n a l y s e t h e d a t a o f t h e 2 r e p l i c a t i o n s w e l l as t h a t o f t h e sexes s e p a r a t e l y .  as  I n the o v e r a l l analyses the s i r e l i n e  as w e l l as t h e 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 h a t c h , 6 and 7 weeks o f age.  However, t h e s e x e f f e c t was s i g n i f i c a n t from h a t c h and  consistently  s i g n i f i c a n t up t h r o u g h 7 weeks o f a g e . The mean body w e i g h t s f o r each sex are p r e s e n t e d i n T a b l e 26 and showed,as e x p e c t e d , t h a t t h e d i f f e r e n c e s were i n f a v o u r o f t h e 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  a l m o s t a l l o f the w e e k l y w e i g h t s t e s t e d w i t h t h e e x c e p t i o n o f t h e body w e i g h t s a t 2 , 5 and 7 weeks o f age ( T a b l e 2 5 ) . From T a b l e 26 i t c a n be seen t h a t t h e mean body w e i g h t s o f t h e progeny i n r e p l i c a t i o n 2 were  consistently  h i g h e r than t h o s e i n r e p l i c a t i o n 1 even i n t h o s e weeks t h a t d i d n o t demonstrate  significance.  A g a i n t h e d i f f e r e n c e between t h e 2 r e p l i c a t i o n s  was  very evident. The a n a l y s e s o f v a r i a n c e o f t h e body w e i g h t s o f t h e male progeny are p r e s e n t e d i n T a b l e 2 7 . The s i r e and dam l i n e e f f e c t s were  significant  a t h a t c h and n o t 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 o f age f o r t h e dam l i n e s and a t 7 weeks o f age f o r t h e s i r e l i n e s .  I t was o f i n t e r e s t t o  n o t e t h a t t h e s i r e x dam i n t e r a c t i o n was n o t s i g n i f i c a n t a t h a t c h b u t was s i g n i f i c a n t f o r e v e r y 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 t h e male  TABLE 2 6 . MEAN CHICK BODY WEIGHTS OF MALE AND FEMALE PROGENY BY REPLICATION  Mean body w e i g h t (gm.) Time o f weighing (week)  Male  Female Replication 1  Replication  Replication 1  Replication 2  Replication 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 . 0 5 ) .  Male  Female  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  Time o f w e i g h i n g (week) Source o f variation  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*  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  Residual  9  6.62  31.4  54  206  349  700  1,097  1,973  31  266.88  1,027.5  3,576  6,727  14,195  24,352  59,805  65,234  Total  * Significant  (P _< 0 . 0 5 ) .  851  - 63 -  c h i c k s was s i g n i f i c a n t  a t 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  6 weeks o f age b u t n o t s i g n i f i c a n t  up t h r o u g h  a t 7 weeks o f a g e . The s i r e :x r e p l i c a -  t i o n a s w e l l a s t h e dam x r e p l i c a t i o n  interaction  were n o n - s i g n i f i c a n t  throughout t h e e n t i r e p e r i o d o f s t u d y . T a b l e 28 p r e s e n t s t h e mean body w e i g h t s of t h e male progeny f o r t h e s i r e and dam l i n e s .  The MH and t h e UBC l i n e s were h o t s i g n i f i c a n t l y  differ-  ent from each o t h e r a t h a t c h i n g b u t b o t h were s i g n i f i c a n t l y h e a v i e r t h a n t h e BA and the NH l i n e . differences. different  A similar  comparison e x i s t e d f o r t h e dam l i n e  I t showed t h a t t h e MH and t h e UBC l i n e s were n o t s i g n i f i c a n t l y  from each o t h e r a t h a t c h b u t b o t h were s i g n i f i c a n t l y h e a v i e r t h a n  t h e BA and the NH l i n e . at h a t c h i n g . the l i g h t e s t  The BA was s i g n i f i c a n t l y l i g h t e r  t h a n t h e NH l i n e  The dam l i n e e f f e c t showed a t 6 weeks o f age t h e MH l i n e was and s i g n i f i c a n t l y d i f f e r e n t  significantly different  from the BA and t h e NH l i n e b u t n o t  from t h e UBC l i n e .  F o r t h e same p e r i o d o f time t h e  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 t h e l i g h t e s t body w e i g h t s b u t i t was n o t s i g n i f i c a n t l y d i f f e r e n t  average  from any o t h e r l i n e .  At  7 weeks o f age t h e MH, t h e UBC, and t h e BA dam l i n e s were n o t s i g n i f i c a n t l y different lines. lightest  from each o t h e r b u t a l l were s i g n i f i c a n t l y l i g h t e r  t h a n t h e NH  I n c o n t r a s t , f o r t h e s i r e l i n e s t h e MH l i n e progeny w e r e , a g a i n , t h e i n body w e i g h t and t h e y were 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 BA l i n e .  I n g e n e r a l t h e male progeny o f the MH s i r e and dam l i n e s  were n o t 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 ever, starting  from t h e UBC  from t h e o t h e r 3 l i n e s .  How-  a t 3 weeks o f age f o r t h e dam l i n e and 4 weeks o f age f o r t h e  TABLE 28.  SIRE AND DAM LINE MEAN BODY WEIGHTS OF MALE PROGENY FROM HATCH TO 7 WEEKS OF AGE  Mean body weight o f c h i c k s (gm.) Time o f weighing (week)  Sire line  Dam l i n e  BA  MH  NH  UBC  Hatch  39b  40a  38b  40a  1  70a  74a  72a  2  144a  148a  3  242a  243a  BA  MH  NH  UBC  37C  40a  39b  40a  73a  70 a  73 a  73a  72a  149a  150a  146a  147a  150a  148a  250a  2503  244a  243a  254a  245a  '  4  36 8 a  362a  380a  377a  370 a  362a  5  516a  501a  532a  526a  517a  50 l  6  676a  651a  698a  687a  676a  7  829a  799 b  865a  848a  83 3 b  b  386 a  369 a  544a  514a  649 b  714 a  673ab  79 8 b  881a  829 b  a  Those means w i t h i n t h e same row o f each s i r e o r dam l i n e which c a r r y the same s u p e r s c r i p t are n o t s i g n i f i c a n t l y d i f f e r e n t (P > 0 . 0 5 ) .  i OS  i  - 65 -  sire  line  the MH males were c o n s i s t e n t l y l i g h t e r than the progeny o f  other l i n e s .  In g e n e r a l , the progeny o f the NH f o r the s i r e  the  l i n e and dam  l i n e were h e a v i e r than the o t h e r 3 l i n e s s t a r t i n g at 2 weeks of age f o r the dam l i n e ,  and a t 4 weeks of age f o 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 n e s was most i n t e r e s t i n g . It  i n d i c a t e d the unequal response i n the progeny f o r mating g r o u p s .  e s t i m a t e o f the s i r e , shown i n T a b l e 29.  It  dam and i n t e r a c t i o n e f f e c t s is  evident  that  The  f o r the male progeny a r e  the s i r e x dam i n t e r a c t i o n e f f e c t  the 4 i n b r e d l i n e s ; BA, MH, NH and UBC, i n a l l cases had h i g h n e g a t i v e w h i l e the m a j o r i t y  o f the c r o s s b r e d s were p o s i t i v e .  T h e r e f o r e , the  of  values  signi-  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 T a b l e 27 was b a s i c a l l y due to the i n b r e d p r o g e n y .  The BA purebreds c o n s i s t e n t l y showed the  n e g a t i v e i n t e r a c t i o n d e v i a t i o n s t a r t i n g at 1 week of age.  greatest  The d e v i a t i o n  of the NH and UBC p u r e b r e d s were s i m i l a r and i n c r e a s e d over t h a t of the MH purebreds s t a r t i n g at 2 weeks of age. interaction effect  o f the 3 l i n e s .  The MH purebreds showed the  T h i s o f course r e f l e c t s  least  the n o n - a d d i t i v e  g e n e t i c c o n t r i b u t i o n f o r body weight i n the progeny o f the i n b r e d l i n e crosses. The a n a l y s e s o f v a r i a n c e o f body weights o f 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 h a t c h and n o n - 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 5,  6 and 7 weeks w h i l e the s i r e e f f e c t was n o n - s i g n i f i c a n t  from h a t c h to 5 weeks of age but was s i g n i f i c a n t at 6 and 7 weeks o f age. general,  this  r e s u l t was i n agreement w i t h the male progeny ( T a b l e 2 7 ) .  In The  - 66 TABLE  29. S I R E , DAM AND S I R E x DAM INTERACTION E F F E C T S (GM.) ON THE BODY WEIGHTS OF MALE PROGENY FROM HATCH TO 7 WEEKS OF AGE  Hatch BA  MH  NH  UBC  Dam effect  BA  0  1  0  0  -2  MH  0  0  1  0  1  1  0  0 1  -1  NH UBC Sire  effect  -1  0  0  1  -1  0  1  -1  1  1 week Dam effect  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  2  0  1  NH  UBC  1  4  -2  . 2  0  -1  Sire  effect  -2  2 weeks Dam BA  -8  BA  MH  4  effect  MH  4  -4  NH  4  2  -6  2  2  UBC  3  0  3  -5  0  -4  0  1  2  Sire  effect  Continued  - 67 TABLE 29.  (Continued)  3 weeks effect  BA  MH  NH  BA  -18  7  4  4  -2  MH  5  -8  1  -1  -3  NH  7  2  -12  4  8  UBC  5  -2  5  -10  -1  -4  -3  4  4  Sire effect  UBC  4 weeks Dam effect  BA  MH  NH  BA  -26  12  8  8  -2  MH  10  -10  0  1  -10  NH  9  4  -17  5  14  UBC  7  -3  9  -12  -3  -4  -10  8  5  Sire effect  UBC  5 weeks Dam effect  BA  MH  NH  UBC  BA  -36  15  11  11  MH  16  -11  -2  0  -18  NH  11  4  -21  5  25  9  -6  13  -17  -5  -3  -18  13  7  UBC Sire effect  "  -2  Continued  - 68 -  TABLE  29.  (Continued)  6  weeks  uam BA  MH  NH  UBC  BA  -44  20  12  13  -2  MH  19  -14  -6  2  -29  NH  10  5  -24  7  36  UBC  13  -10  18  -22  -5  -2  -27  20  9  Sire  effect  effect  7 weeks  Dam BA  MH  NH  UBC  -51  22  17  11  -2  MH  27  -17  -13  3  -37  NH  7  11  -26  8  46  16  -15  22  -24  -6  -6 .  -36  30  13  BA  UBC Sire  effect  effect  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  Time o f w e i g h i n g (week) Source o f variation  d.f.  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  31  279.97  1,218.0  3,464  4,784  9,945  14,314  36,116  36,908  Total  ^Significant  (P <_ 0 . 0 5 ) .  - 70 -  s i r e x dam i n t e r a c t i o n progeny,  f o r the f e m a l e progeny was i d e n t i c a l t o t h e m a l e  i t was n o t s i g n i f i c a n t a t h a t c h B u t was s i g n i f i c a n t f o r e v e r y week  thereafter.  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 a t h a t c h f o r t h e male  p r o g e n y , 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 t h r o u g h 7 weeks o f a g e . The f e m a l e  progeny a l s o showed a s t r o n g 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 t h e 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 t h r o u g h o u t t h e e n t i r e p e r i o d o f s t u d y w i t h t h e e x c e p t i o n o f body w e i g h t a t 4 weeks o f a g e . These i n t e r a c t i o n s  were p r o b a b l y t h e r e s u l t o f s a m p l i n g  e r r o r s , s i n c e t h e same e f f e c t was n o t found i n t h e males a t any age l e v e l . The s i r e and dam l i n e mean body w e i g h t s o f the f e m a l e progeny a t w e e k l y i n t e r v a l s from h a t c h t o 7 weeks o f age a r e shown i n T a b l e 3 1 . From h a t c h t o 5 weeks o f age a l l t h e means o f t h e 4 s i r e l i n e s were n o t s i g n i f i c a n t l y d i f ferent.  However, from h a t c h t o 3 weeks t h e mean body w e i g h t s o f t h e BA s i r e  l i n e was t h e l o w e s t , w h i l e t h e UBC s i r e had t h e h i g h e s t mean body w e i g h t a t 2 and 3 weeks o f a g e . From 4 weeks o f age and t h e r e a f t e r t h e NH l i n e had the h i g h e s t mean body w e i g h t w h i c h was analogous t o t h e male d a t a ( T a b l e 2 8 ) . A t 6 and 7 weeks o f age t h e mean body w e i g h t o f t h e BA, NH and t h e UBC s i r e l i n e s were n o t s i g n i f i c a n t l y d i f f e r e n t b u t 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 t h e MH l i n e .  The MH l i n e had t h e l o w e s t mean body w e i g h t a t 4 , 5 , 6 and  7 weeks o f age w h i c h was s i m i l a r t o t h e d a t a o f t h e male progeny ( T a b l e 2 8 ) . The mean body w e i g h t o f t h e BA dam l i n e a t h a t c h was the l o w e s t and s i g n i f i cantly different cantly different.  from t h e o t h e r 3 l i n e s w h i c h themselves were n o t s i g n i f i From 1 t o 4 weeks o f age t h e r e was no s i g n i f i c a n t d i f f e r -  TABLE  3 1 . SIRE AND DAM LINE MEAN BODY WEIGHTS OF FEMALE PROGENY FROM HATCH TO 7 WEEKS OF AGE  Mean body weight of  c h i c k s (gm.)  Sire l i n e 1  Time o f  Dam l i n e  weighing (week)  BA  MH  NH  UBC  Hatch  38a  39 3  38a  3 9  1  67a  72a  69a  BA  MH  NH  UBC  36 b  40a  39 3  39a  70 a  68a  71a  69a  69a  a  2  133 a  139 a  138a  140a  135a  140 a  138a  137a  3  215a  220a  225a  226a  218a  222a  226a  2203  4  319 a  317a  332a  331 a  320 3  32la  337a  322a  5  439a  430a  455a  448a  437 b  434 b  46 3 a  438 b  6  56 3 a  ' 542b  583a  568a  557 b  548 b  59 3 a  558 b  7  683a  651b  7073  683a  675 b  656 b  719a  6 74 b  Those means w i t h i n t h e same row o f each s i r e o r dam l i n e which c a r r y t h e same s u p e r s c r i p t are n o t s i g n i f i c a n t l y d i f f e r e n t (P > 0 . 0 5 ) .  - 72 -  ence e x i s t i n g among t h e s e 4 l i n e s . significance,  However, r e g a r d l e s s o f t h e l a c k o f  the BA dam l i n e had t h e l o w e s t mean body w e i g h t from h a t c h  up t h r o u g h 4 weeks o f a g e , w h i l e the MH dam l i n e had t h e h e a v i e s t -mean body w e i g h t from h a t c h t o 2 weeks o f age and t h e NH dam l i n e had t h e h e a v i e s t mean body w e i g h t from 3 weeks o f 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 a t 5 weeks and up t o 7 weeks o f a g e .  In general,  t h e r e was f a i r l y good agreement between sexes as measured by t h e s i r e and t h e dam l i n e means.  The s i r e x dam i n t e r a c t i o n  had a s i m i l a r r e s p o n s e as t h e -male p r o g e n y . x dam i n t e r a c t i o n  f o r the female  The m a i n s o u r c e o f t h e s i r e  f o r f e m a l e s , as i n t h e males,appeared  e f f e c t of the matings w i t h i n the purebred l i n e s  t o be due to. t h e  (Table 32).  I t s h o u l d be  n o t e d t h a t t h e NH female progeny showed the h i g h e s t i n t e r a c t i o n compared t o t h e BA male p r o g e n y .  progeny  e f f e c t as  A g a i n t h i s may be f u r t h e r e v i d e n c e f o r t h e  need t o s e p a r a t e t h e sexes f o r a n a l y t i c a l p u r p o s e s .  The mean body w e i g h t s  based on r e p l i c a t i o n w i t h i n each s e x a r e l i s t e d i n T a b l e 2 6 .  In general,  males and f e m a l e s 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 t h a n t h e males and f e m a l e s i n r e p l i c a t i o n 2.  T h i s d i f f e r e n c e was o b s e r v a b l e a t h a t c h i n g  and c o n s i s t e n t r i g h t t h r o u g h 7 weeks o f a g e .  However, t h e means a t 7 weeks  o f age were n o t s i g n i f i c a n t l y d i f f e r e n t . C h i c k Growth R a t e s The mean c h i c k w e e k l y growth r a t e s from h a t c h (H) t o 7 weeks o f age are p r e s e n t e d i n T a b l e 3 3 . The a n a l y s e s o f v a r i a n c e i n T a b l e 34 showed t h a t o n l y 1 second o r d e r 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  replication)  - 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 effect  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  Sire effect  0  1  0  1  1 week  Dam effect  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  -2  3  0  1  Sire effect  2 weeks  Dam effect  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  -4  2  1  3  Sire effect  Continued  - 74 TABLE  32.  (Continued)  3 weeks BA  NH  MH  UBC  Dam effect  BA  -6  1  0  3  -3  MH  0  -5  4  -1  1  NH  4  3  -10  3  5  UBC  3  -2  4  -9  -1  -6  -1  4  5  Sire  effect  4 weeks BA  NH  MH  UBC  Dam effect  BA  -9  3  4  4  -5  MH  1  -6  6  1  -4  NH  5  6  -16  5  12  UBC  4  -2  7  -11  -3  -6  -8  7  6  Sire  effect  5 weeks BA  MH  NH  UBC  Dam effect  BA  -13  2  6  6  -6  MH  1  -7  6  7  -9  NH  8  9  -21  4  20  UBC  4  -4  9  -9  -5  -4  -13  12  5  Sire  effect  Continued  - 75 TABLE  32. ( C o n t i n u e d )  6 weeks BA  MH  NH  BA  -16  5  6  4  -7  MH  1  -8  5  2  -16  NH  10  10  -24  5  29  UBC  -7  -6  11  -11  -6  -1  -22  19  4  Sire  effect  UBC  effect  7 weeks Dam effect  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  26  2  Sire  effect  2  '  -30  - 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 line BA Dam line  Week  M  MH  F  M  NH  F  M  UBC  F  Mean  M  F  M  BA  H-l 1-2 2-3 3-4 4-5 5-6 6-7  1.94 3.27 2.78 2.80 2.56 2.34 1.98  1.96 3.02 2.67 2.58 2.40 2.16 1.84  2.20 3.19 2.78 2.63 2.45 2.22 1.93  2.15 3.01 2.52 2.39 2.28 2.00 1. 78  2.32 3.32 2.93 2.74 2.52 2.28 2.06  2.21 3.16 2.77 2.62 2.38 2.09 1.92  2.28 2.16 3.28 3.17 2.80 2.62 2.72 2.46 2.50 2.28 2.27 1.97 1.94 1.80  2.19 3.26 2.82 2.72 2.51 2.28 1.98  2.12 3.09 2.64 2.51 2.33 2.05 1.83  MH  H-l 1-2 2-3 3-4 4-5 5-6 6-7  2.02 3.21 2.79 2.66 2.50 2.18 1.97  1.88 3.03 2.62 2.48 2.34 2.02 1.79  2.00 3.05 2.66 2.54 2.41 2.16 1.93  2.02 2.94 2.46 2.31 2.23 1.92 1.62  2.16 3.19 2.80 2.58 2.44 2.19 1.96  2.17 3.04 2.58 2.43 2.26 2.00 1.70  2.00 2.18 2.76 2.60 2.43 2.22 2.00  2.02 3.06 2.54 2.40 2.22 1.94 1.75  2.05 3.16 2.75 2.59 2.45 2.19 1.97  2.02 3.02 2.55 2.40 2.26 1.97 1.71  NH  H-l 1-2 2-3 3-4 4-5 5-6 6-7  2.21 3.23 2.93 2.74 2.56 2.30 1.89  1.96 3.12 2.78 2.66 2.47 2.14 1.86  2.22 3.20 2.80 2.64 2.50 2.27 2.02  2.14 3.04 2.64 2.50 2.36 2.00 1.79  2.03 3.28 2.91 2.77 2.64 2.38 2.09  1.80 3.16 2.78 2.60 2.46 2.18 1.91  2.14 3.30 2.90 2.70 2.55 2.30 2.02  2.05 3.10 2.68 2.53 2.30 2.06 1. 76  2.15 3.25 2.89 2.72 2.56 2.31 2.00  1.99 3.10 2.72 2.57 2.40 2.10 1.83  UBC  H-l 1-2 2-3 3-4 4-5 5-6 6-7  2.06 3.28 2.82 2.70 2.50 2.32 1.94  1.92 3.12 2.59 2.52 2.36 2.14 1.80  2.02 3.13 2.66 2.56 2.39 2.22 1.93  1.98 3.00 2.45 2.36 2.24 1.97 1.73  2.17 3.24 2.83 2.70 2.52 2.32 2.04  2.02 3.12 2.65 2.52 2.34 2.10 1.86  1.96 3.22 2.75 2.69 2.49 2.30 2.04  1.92 3.04 2.65 2.49 2.35 2.02 1.74  2.05 3.22 2.77 2.66 2.47 2.29 1.98  1.96 3.06 2.58 2.47 2.32 2.06 1.78  Mean  H-l 1-2 2-3 3-4 4-5 5-6 6-7  2.05 3.25 2.83 2.72 2.53 2.29 1.94  1.93 3.07 2.67 2.56 2.39 2.12 1.82  2.11 3.14 2.73 2.59 2.44 2.22 1.95  2.07 3.00 2.51 2.39 2.27 1.97 1.73  2.17 3.26 2.87 2.70 2.53 2.29 2.04  2.05 3.12 2.69 2.54 2.36 2.09 1.84  2.10 3.25 2.80 2.68 2.49 2.27 2.00  2.04 3.09 2.62 2.47 2.29 2.00 1.76  2.11 3.22 2.81 2.67 2.50 2.27 1.98  2.02 3.07 2.62 2.49 2.33 2.04 1.79  - 77 -  f o r t h e RVL and 4^5 week g r o w t h r a t e s . interactions  T h e r e f o r e , a l l o f t h e second o r d e r  were p o o l e d f o r t e s t i n g p u r p o s e s .  The s i r e x dam  interaction  f o r the w e e k l y growth r a t e s ' H V L , 4-^5 and 5—6 were s i g n i f i c a n t , w h i l e t h e 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  e x c e p t f o r the w e e k l y growth r a t e s o f 5-6 and 6^7. No s i g n i f i c a n t of dam x s e x i n t e r a c t i o n of those i n t e r a c t i o n s  was o b s e r v e d .  The p r e s e n c e o f s i g n i f i c a n t  effect effects  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 t h a t i t would be a d v i s a b l e  to a n a l y s e t h e c h i c k growth r a t e d a t a s e p a r a t e l y f o r t h e 2 r e p l i c a t i o n s . s i g n i f i c a n t s i r e l i n e as w e l l a s dam l i n e e f f e c t  A  ( T a b l e 34) was o b s e r v e d f o r  a l l growth r a t e p e r i o d s s t u d i e d w i t h t h e e x c e p t i o n o f t h e growth r a t e from H-l.  T h i s was i n c o n t r a s t t o t h e body w e i g h t d a t a i n t h a t s i r e and dam  line effects  a l t h o u g h s i g n i f i c a n t a t h a t c h , d i d n o t demonstrate  significance  a g a i n u n t i l 6 weeks o f age ( T a b l e 2 5 ) . The s e x e f f e c t a s w e l l as t h e 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 p e r i o d s o f growth t e s t e d .  This i s i n  agreement w i t h t h e body w e i g h t d a t a . The mean c h i c k growth r a t e s f o r s e x and r e p l i c a t i o n s  showed  that  t h e 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 t h a n t h e female p r o geny f o r each w e e k l y growth p e r i o d ( T a b l e 3 5 ) . These sex d i f f e r e n c e s demons t r a t e d a g a i n t h a t i t would be more d e s i r a b l e t o a n a l y s e t h e d a t a f o r each sex  separately.  I n 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 l o w e r w e e k l y  growth r a t e t h a n t h e progeny i n r e p l i c a t i o n 1 except f o r t h e H - l and 5-6 week growth r a t e s . nificant.  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 -  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  P e r i o d of growth (week) source or Variation  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  1  0.0039  0.0088 .  0.0039  0.0002 .  0.0001  0.0005  0.0006  x R  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  9  0.0371  0.0152  0.0152  0 .0150  0.0048  0.0114  0.0595  63  1.4986  0.8854  2.0492  1.1119  1.4949  2.0146  6.8673  Residual  Total  Significant  (P <_ 0 . 0 5 ) .  TABLE  35. MEAN CHICK GROWTH RATES OF MALE AND FEMALE PROGENY BY REPLICATION  Mean growth r a t e Growth period (week)  Male Replication 1  Replication  Female Replication 2  Replication 1  Replication 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 c a t e g o r i e s of m a l e , f e m a l e , sex and r e p l i c a t i o n (P <_ 0 . 0 5 ) .  - 80 -  The a n a l y s e s ' o f v a r i a n c e o f w e e k l y g r o w t h r a t e s o f - m a l e s ' f r o m h a t c h to 7 weeks o f age i n T a b l e 36 showed t h e w e e k l y g r o w t h r a t e s o f t h e m a l e progeny f o r t h e 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 p e r i o d s e x c e p t f o r t h e H - l and 6-7 week growth r a t e s . t o t h e m a l e body w e i g h t a n a l y s e s  Whereas i n c o n t r a s t  ( T a b l e 27) and t h e a n a l y s e s f o r b o t h sexes  ( T a b l e 25) t h e s i r e x dam i n t e r a c t i o n s growth p e r i o d .  for a l l  were n o t s i g n i f i c a n t f o r any w e e k l y  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 t h e 2-3 week  g r o w t h r a t e and a l l subsequent w e e k l y g r o w t h r a t e s . f i r s t order i n t e r a c t i o n s replication interaction  There were no o t h e r  s i g n i f i c a n t w i t h the s i n g l e exception of the s i r e x f o r t h e 6-7 week growth  rate.  The female progeny ( T a b l e 3 7 ) , as i n t h e male p r o g e n y , t h e 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 . f o r a l l w e e k l y growth p e r i o d s was s i g n i f i c a n t .  The s i r e  effect  The dam e f f e c t was  cant s t a r t i n g a t t h e 2-3 week growth r a t e , and i t was s i g n i f i c a n t  signifithereafter.  S i m i l a r l y t o t h e male p r o g e n y , t h e female progeny d i d n o t 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 t h e s i n g l e e x c e p t i o n o f t h e 5-6 week growth rate.  O n l y t h e 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  effect.  The dam x r e p l i c a t i o n e f f e c t was n o t s i g n i f i c a n t f o r a l l p e r i o d s  tested.  C o n t r a s t e d t o t h e body w e i g h t a n a l y s e s i t s h o u l d be p o i n t e d o u t  t h a t t h e body w e i g h t a n a l y s e s were n o t as s e n s i t i v e e f f e c t s as was t h e growth r a t e a n a l y s e s . f o r each s e x r e s u l t e d interactions  i n determining  In addition,  the separate  line analyses  i n m i n i m i z i n g t h e s i g n i f i c a n t f i r s t and second o r d e r  w h i c h were found when t h e 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  P e r i o d o f growth (week) source or variation  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  31  0 .67  0,.24  0 .62  0 .24  0 .51  0 .60  3. 17  Total  *Significant  (P <_ 0 . 0 5 ) .  TABLE 37.  SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF WEEKLY GROWTH RATES OF FEMALE PROGENY FROM HATCH TO 7 WEEKS OF AGE  P e r i o d o f growth (week) Source o f variation  d.f.  Hatch-1  1-2  2-3  3-4  4-5  5-6  6.-7  0.08*  0.12*  0.07*  0.07*  0.07*  0.07*  S i r e l i n e (S)  3  0.10  0 .07*  0.15  0.14*  Dam l i n e (D)  3  0.12  0 .03  0.13*  0.12*  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  31  0.71  0 .28  0.89  0.33  0.53  0.63  3.09  Total  ^Significant  (Pj<0.05).  .  - 83 -  One c a n s p e c u l a t e about t h e i n t e r p r e t a t i o n o f e x p e r i m e n t s , t h a t a n a l y s e d male and female body w e i g h t s i n a combined a n a l y s e s , and as a consequence, d e t e r m i n e d 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 t h e i n t e r -  a c t i o n s a r e n o t h i n g b u t t h e consequence o f u n i q u e m a l e and f e m a l e growth rate differences. The s i r e and dam l i n e mean growth r a t e s o f t h e m a l e progeny a r e p r e s e n t e d i n T a b l e 3 8 , and showed t h e MH l i n e had t h e l o w e s t mean w e e k l y growth r a t e e i t h e r a s t h e s i r e e f f e c t o r as t h e dam e f f e c t .  I n the m a j o r i -  t y o f t h e s e 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 o r 3 lines.  I t s h o u l d be n o t e d t h a t t h e p r i m a r y s o u r c e s o f s i g n i f i c a n c e was  t h e mean growth r a t e o f t h e MH l i n e .  The mean growth r a t e o f t h e f e m a l e  progeny .(Table 39) a l s o i n d i c a t e d t h a t t h e MH l i n e was t h e p r i m a r y s o u r c e of t h e s i r e and dam l i n e e f f e c t i n t h a t i t e x h i b i t e d g e n e r a l l y t h e l o w e s t and u s u a l l y s i g n i f i c a n t w e e k l y growth r a t e o f t h e o t h e r 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 s e x f o r w e e k l y growth r a t e s i s shown i n T a b l e 35.  On t h e a v e r a g e , t h e males o f 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 h i g h e r  w e e k l y growth r a t e t h a n t h e males o f r e p l i c a t i o n 2.  The e x c e p t i o n b e i n g  the H - l growth r a t e ( n o n - s i g n i f i c a n t ) and t h e 5-6 growth r a t e smaller).  (significantly  The female progeny f o l l o w e d t h e same p a t t e r n a s d i d t h a t o f t h e  males i n r e p l i c a t i o n 1. growth r a t e .  R e p l i c a t i o n 1 on t h e average had t h e h i g h e r w e e k l y  S i n c e 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 s h o u l d be n o t e d t h a t t h e 5-6 week growth r a t e was l o w 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 t h e 6-7 week growth r a t e was e x t r e m e l y  TABLE 38. SIRE AND DAM LINE MEAN GROWTH RATES OF MALE PROGENY DURING WEEKLY INTERVALS FROM HATCH TO 7 WEEKS OF AGE  Mean growth r a t e Period of growth (week)  Dam l i n e  1 Sire l i n e  MH  NH  UBC  UBC  BA  2.17 3  2.10 3  2.19 a  2.05 3  2.15 3  2.05 a  3.14 b  3.26 a  3.25 a  3.26 a  3.16 b  3.25 3  3.22 a  2.83ab  2.73°  2.87 3  2.80 b  2.82 b  2.75°  2.89 a  2.77bC  3-4  2.72a  2.59 C  2.70ab  2.68 b  2.72 a  2.59°  2.72 a  2.66 b  4-5  2.53 a  2.44 b  2.53a  2.49  2.51 b  2.45 C  2.56 a  2.47bC  5-6  2.87 a  2.22 b  2.29 a  2.27 a  2.28 a  2.19 b  2.3la  2.29 a  6-7  1.94 a  1.95 a  2.04 a  2.00 a  1.98 3  1.97 a  2.00 3  1.98 a  BA  MH  Hatch-1  2.05a  2.113  1-2  3.25 a  2-3  NH  Those means w i t h i n t h e same row o f each s i r e o r dam l i n e which c a r r y t h e same s u p e r s c r i p t are n o t s i g n i f i c a n t l y d i f f e r e n t (P > 0 . 0 5 ) .  TABLE  39. SIRE AND DAM LINE MEAN GROWTH RATES OF FEMALE PROGENY DURING WEEKLY INTERVALS FROM HATCH TO 7 WEEKS OF AGE  Mean growth r a t e Sire line1  Period of growth (week)  BA  MH  NH  Dam l i n e UBC  BA  MH  NH  UBC  Hatch-1  1.93 3  2.07 3  2.053  2.05 3  2.12 a  2.02 a  1.99 a  1.96 3  1-2  3.07 3  3.00 b  3.12 3  3.09 a  3.09 3  3.02 3  3.10 a  3.07 3  2-3  2.67 a  2.51 b  2.69 a  2.62 a  2.64 b  2.55°  2.72 a  2.58bC  3-4  2.56 a  2.39°  2.54 a  2.47 b  2.51 b  2.40°  2.57 a  2.47 b  4-5  2.393  2.27 b  2.36 a  2.29 b  2.33 b  2.26°  2.40 a  2.32bC  5-6  2.123  2.09 a  2.00 b  2.05 3  1.97 b  2.10 3  2.06 a  6-7  1.82 a b  1.97 b c 1. 73  1.84 a  1. 7 6 b c  1.83 a  1.71  1.83 a  1.78 a b  b  Those means w i t h i n the same row o f each s i r e o r dam l i n e which c a r r y 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 . 0 5 ) .  - 86 -  low. are  The reason i s unknown b u t e x c l u d i n g the H - l week growth r a t e t h e s e the lowest gains i n each  replication.  Average C h i c k Growth Rates The  combined growth r a t e s o f t h e progeny f o r each mating f o r the  H-3, 1-3, 3-7, H-7 and 1-7 week growth r a t e a r e shown i n T a b l e 40. analyses of variance no f i r s t  ficant  ( T a b l e 41) showed t h a t f o r t h e H-3 week growth r a t e  o r second o r d e r i n t e r a c t i o n s  s i r e x dam.  In f a c t  were e v i d e n t except t h a t o f t h e  t h e s i r e x dam i n t e r a c t i o n s  growth r a t e was t e s t e d  the s i r e x s e x x r e p l i c a t i o n  r e p l i c a t i o n were b o t h s i g n i f i c a n t . order interactions  both s i g n i f i c a n t , interactions  i n addition  x replication  the  s i r e l i n e s , dam l i n e s  were s i g n i f i c a n t .  A l l interactions  were  dam x s e x and s i r e x foroverall  growth  replication,  The d a t a s t r o n g l y  need t o be a n a l y s e d s e p a r a t e l y .  suggests  In general  and s i r e x dam as w e l l as the s e x and r e p l i c a t i o n  The s i n g l e  H-3 week growth r a t e .  The 3-7 week growth  except f o r the dam x s e x x  and dam x s e x i n b o t h t r a i t s .  t h a t sexes and r e p l i c a t i o n s  dam x sex, s i r e  and s i r e x dam x r e p l i c a t i o n  the s i r e x r e p l i c a t i o n ,  r a t e s H-7 and 1-7 were s i g n i f i c a n t sex  and t h e s i r e x dam x  were a l s o s i g n i f i c a n t .  were s i g n i f i c a n t .  signi-  When t h e 1-3 week  The s i r e x r e p l i c a t i o n ,  r a t e showed t h e s i r e x s e x x r e p l i c a t i o n  sex  were s t a t i s t i c a l l y  i n the a n a l y s e s o f a l l combined growth p e r i o d s .  x sex f i r s t  The  e x c e p t i o n was the s i r e l i n e e f f e c t  f o r the  A g a i n the argument i s made t h a t the analyses o f the  s e p a r a t e sexes would be d e s i r a b l e .  The mean growth r a t e s averaged by s e x  -  TABLE 40.  MEAN CHICK GROWTH RATES OF MALES (M) AND FEMALES (F) FOR VARYING GROWTH PERIODS ACROSS REPLICATIONS  Sire BA Dam line  Week  87 -  M  line  MH F  M  NH F  M  UBC F  M  Mean F  M  F  BA  H-3 3-7 1-3 1-7 H-7  2.66 2.42 3.02 2.62 2.52  2.56 2.24 2.85 2.44 2.38  2.73 2.30 2.98 2.53 2.48  2.56 2.11 2.76 2.32 2.30  2.86 2.40 3.12 2.64 2.60  2.72 2.26 2.96 2.50 2.45  2.79 2.36 3.04 2.59 2.54  2.65 2.13 2.90 2.38 2.35  2.76 2.37 3.04 2.60 2.54  2.62 2.18 2.87 2.41 2.37  MH  H-3 3-7 1-3 1-7 H-7  2.68 2.32 3.00 2.56 2.48  2.52 2.16 2.83 2.38 2.31  2.56 2.26 2.85 2.46 2.39  2.47 2.02 2. 70 2.24 2.21  2.72 2.30 3.00 2.53 2.48  2. 60 2. 10 2. 81 2. 33 2. 31  2.64 2.31 2.98 2.54 2.46  2.54 2.08 2.80 2.32 2.28  2.65 2.30 2.96 2.52 2.45  2.53 2.08 2. 78 2.32 2.28  NH  H-3 3-7 1-3 1-7 H-7  2.79 2.38 3.08 2.61 2.55  2.62 2.28 2.96 2.50 2.43  2.74 2.36 3.00 2.57 2.52  2.60 2.16 2.84 2.39 2.36  2.74 2.46 3.09 2.68 2.58  2. 58 2. 29 2.96 2. 51 2. 41  2. 78 2.39 3.10 2.62 2.56  2.60 2.16 2.88 2.40 2.36  2. 76 2.40 3.07 2.62 2.55  2.60 2.22 2.91 2.45 2.39  UBC  H-3 3-7 1-3 1-7 H-7  2.72 2.36 3.06 2.60 2.52  2.54 2.20 2.86 2.42 2.35  2.60 2.27 2.90 2.48 2.42  2.48 2.08 2.72 2.30 2.24  2.74 2.40 3.04 2.61 2.54  2. 60 2. 20 2. 88 2. 43 2. 38  2.64 2.38 2.98 2.58 2.49  2.53 2.14 2.84 2.38 2.32  2.68 2.35 3.00 2.57 2.49  2.54 2.16 2.83 2.38 2.32  Mean  H-3 3-7 1-3 1-7 H-7  2.71 2.37 3.04 2.60 2.52  2.56 2.22 2.87 2.44 2.37  2.66 2.30 2.93 2.51 2.45  2.53 2.09 2.76 2.31 2.28  2.76 2.39 3.06 2.61 2.55  2. 62 2. 21 2. 91 2. 44 2. 39  2.71 2.36 3.02 2.58 2.51  2.58 2.13 2.85 2.37 2.32  2.71 2.36 3.02 2.58 2.51  2.57 2.16 2.85 2.39 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  P e r i o d o f growth (wee k) Source o f Variation  d.f.  H-3  3-7  1-3  1-7  H-7  S i r e l i n e (S)  3  0.0822  0.1189*  0.1730*  0.1338*  0.0933*  Dam  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  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  1  0.0010  0.0001  0.0062  0 .0003  0 .0001  line  (D)  Replication  F  (R)  x R  S x  F x R  3  0.0018  0.0038*  0.0019  0 .0014*  0.0008  D x  F  3  0 .0024  0 .0001  0.0021  0 .0004  0.0006  Residual  - 9 •  0.0050  0.0020  0.0028  0 .0004  0.0008  Total  63  0.7268  1.3207  1.2916  1.2751  0.9565  x R  Significant  (P^0.05).  - 89 -  and r e p l i c a t i o n  (Table 42) showed t h a t the female progeny had  consistently  lower growth r a t e s than t h e male p r o g e n y , and t h a t 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 t h a n r e p l i c a t i o n 2 f o r e v e r y growth p e r i o d s t u d i e d . The growth r a t e d a t a of m a l e s were a n a l y s e d s e p a r a t e l y and i n Table 43.  F o r t h e male progeny the s i r e l i n e e f f e c t was  a l l p e r i o d s t e s t e d e x c e p t f o r the H-3 week g r o w t h r a t e . 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 .  the p r e v i o u s a n a l y s e s f o r b o t h sexes was  presented  significant i n  The dam  line  effect  T h i s d i d not d i s a g r e e w i t h  (Table 41).  The  s i g n i f i c a n t o n l y f o r t h e EV7 week growth r a t e .  s i r e x dam  Significance  interaction was  ob-  s e r v e d i n the a n a l y s e s f o r b o t h sexes f o r t h i s one p e r i o d , however, t h e male progeny a n a l y s e d s e p a r a t e l y d i d n o t show any o t h e r s i r e x dam tion.  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 p e r i o d s was  I t appeared t h a t the s i g n i f i c a n t s i r e x dam attributable  as e x p e c t e d , was  shown i n T a b l e  i n t e r a c t i o n would be  to the combined a n a l y s e s o f b o t h s e x e s .  interac-  The  basically  replication  s i g n i f i c a n t i n e v e r y p e r i o d f o r the e n t i r e  study.  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 t h e dam x r e p l i c a t i o n were not s i g n i f i c a n t w i t h the e x c e p t i o n of the H-7 both i n t e r a c t i o n s interaction.  effect,  The interactions  week g r o w t h r a t e f o r  and f o r t h e 3-7 week growth r a t e f o r the s i r e x  T h i s was  41.  replication  i n good agreement w i t h t h e a n a l y s e s f o r b o t h  sexes  (Table 41). The  a n a l y s e s of the female progeny ( T a b l e 44) showed the  e f f e c t s of the s i r e and dam t h e male p r o g e n y .  The  significant  l i n e s o c c u r r e d i d e n t i c a l l y t o the a n a l y s e s o f  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 4 2 . MEAN CHICK GROWTH RATES OF MALE AND FEMALE PROGENY BY REPLICATION  Mean growth r a t e Growth period (week)  Male Replication 1  Female Replication 2  Replication 1  Replication  Replication 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 . 0 5 ) .  TABLE  A3. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF MALE PROGENY FOR VARYING GROWTH PERIODS  P e r i o d o f growth (week) Source o f variation  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  R e p l i c a t i o n (R)  1  0.04*  0.21*  0.17*  S x R  3  <0.01  D x R  3  <0.01  Residual  9  31  Total  Significant  (P < 0 . 0 5 ) .  <0.01 0.20*  <0.01 0.12*  <0,01  <0.01  <0.01*  <0.01  0.01  <0.01  <0.01*  0.01  <0.01  0.01  <0.01  <0 .01  0 .22  0.33  0 .35  0.32  0.23  0 .01*  TABLE 44. SUMS OF SQUARES FROM THE ANALYSES OF VARIANCE OF FEMALE PROGENY FOR VARYING GROWTH PERIODS  P e r i o d o f growth (week) Source o f Variation  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.oi  <0.01  <0.01  <0.01  <0.01  Residual  9  <0.01  <0.01  0.02  <0.01  <0.01  31  0.19  0.40  0.49  0.41  0.26  Total  *Signifleant  (P £ 0 . 0 5 ) .  - 93 -  progeny f o r t h e R-r-3 and UrJ week g r o w t h r a t e s .  Comparison t o t h e male d a t a  (Table 43) o n l y t h e RV7 week g r o w t h r a t e was s i g n i f i c a n t .  The a n a l y s e s f o r  b o t h sexes ( T a b l e 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 , t h e 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 e v e r y growth p e r i o d except f o r t h e 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 o f 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 t h e female progeny a n a l y s e s . T h e r e f o r e t h e s e i n t e r a c t i o n s measurable i n t h e composite a n a l y s e s were due t o t h e male d a t a shown i n T a b l e 4 3 . The mean growth r a t e s o f t h e male progeny f o r t h e s i r e l i n e s  (Table  45) shows t h e r e 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 t h e H-3 week growth r a t e b u t i t s h o u l d be n o t e d t h a t t h e MH l i n e d i d have the l o w e s t growth r a t e . F o r t h e growth r a t e o f 1-3, 3-7 and 1-7 weeks t h e MH s i r e l i n e had t h e l o w e s t means, and t h e y were s i g n i f i c a n t l y d i f f e r e n t from t h e o t h e r 3 l i n e s , w h i c h were n o t s i g n i f i c a n t l y d i f f e r e n t .  The growth o f t h e MH f o r H-7 week  growth r a t e was t h e l o w e s t w h i l e t h e NH had t h e h i g h e s t growth r a t e and b o t h were s i g n i f i c a n t l y d i f f e r e n t from t h e BA and t h e UBC l i n e s w h i c h were n o t significantly different.  The dam l i n e v a l u e s gave t h e s i m i l a r r e s u l t s t o  t h e s i r e l i n e s , the NH dam progeny had t h e h i g h e s t mean growth r a t e s f o r e v e r y growth p e r i o d s t u d i e d , w h i l e t h e MH l i n e u s u a l l y had t h e l o w e s t mean growth r a t e s f o r every period s t u d i e d .  I t was o f i n t e r e s t t o n o t e t h a t t h e c l o s e n e s s  o f t h e s i r e and dam l i n e v a l u e s f o r t h e growth r a t e a n a l y s i s , f o r e x a m p l e , 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 t h e 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 Period of growth (week)  Sire line BA  MH  1 NH  Dam l i n e UBC  BA  1-3  3.04 a  2.93 b  3.06 a  3.02 a  3.04 a b  3-7  2.37 a •  2.30 b  2.39 a  2.36 a  2.37 a  MH  NH  2.96° 2.30 b C  UBC  3.07 a  3.00bc  2.40 3  2.35 3  2.62 a  2.57 b  2.60 a  2.51 b  2.61a  2.58 a  2.60ab  2.52  Hatch-3  2.71 a  2.65 a  2.76 a  2.71 3  2.76 a  2.65 b  2.76 a  2.68ab  Hatch-7  . 2.52 b  2.45 C  2.55 a  2.51 b  2.54 a  2.45°  2.55 a  2.49 b  1-7  Those means w i t h i n the same row o f each s i r e o r dam l i n e which c a r r y t h e same s u p e r s c r i p t are n o t s i g n i f i c a n t l y d i f f e r e n t (P > 0 . 0 5 ) .  - 95 -  The  s i r e and dam l i n e mean growth, r a t e s o f t h e f e m a l e progeny i n  T a b l e 46 shows, i n g e n e r a l , t h e p a t t e r n o f d i f f e r e n c e among t h e l i n e s was similar  t o t h a t o f the male p r o g e n y .  The NH s i r e and dam l i n e progeny had  t h e h i g h e s t mean growth r a t e s and t h e MR s i r e and dam l i n e progeny gave t h e l o w e s t mean f o r e v e r y g r o w t h p e r i o d t e s t e d .  The BA, as w e l l as t h e UBC  l i n e had the i n t e r m e d i a t e growth r a t e s , and i n g e n e r a l , were n o t 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 , b u t s i g n i f i c a n t l y n i f i c a n t l y h i g h e r than t h e MH l i n e . lines.  lower than t h e NH and s i g -  T h i s h o l d s t r u e f o r b o t h s i r e and dam  A g a i n n o t e t h e extreme c l o s e n e s s o f t h e v a l u e s . o b t a i n e d f o r t h e s i r e  l i n e and dam l i n e f o r t h e 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 t h e r e p l i c a t i o n  w i t h i n each s e x  a r e g i v e n i n T a b l e 42 and i t showed t h a t t h e males as w e l l as t h e f e m a l e s i n replication  1 had t h e 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 t h o s e i n  replication  2 f o r a l l p e r i o d s s t u d i e d w i t h t h e e x c e p t i o n o f t h e H-7 week  growth r a t e o f female progeny o f w h i c h t h e excess o f t h e mean o f  replication  1 was n o t s i g n i f i c a n t . P r e - and P o s t - s t o r a g e Egg Weights The mean p r e - and p o s t - s t o r a g e egg w e i g h t s  i n grams ( T a b l e 47)  showed t h a t t h e l o w e s t egg w e i g h t was t h a t f r o m t h e 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 t h e MH dam p r o d u c i n g t h e l a r g e s t mean egg weight.  T h i s r a n k i n g h e l d t r u e f o r b o t h p r e - and p o s t - s t o r a g e egg w e i g h t s ,  w h i c h i n d i c a t e d t h a t t h e r a t e o f d e h y d r a t i o n o f t h e eggs from t h e s e 4 l i n e s was  presumably v e r y c l o s e .  The a n a l y s e s o f v a r i a n c e t e s t i n g t h e second  TABLE 46.  SIRE AND DAM LINE MEAN GROWTH RATES OF FEMALE PROGENY FOR VARYING GROWTH PERIODS  Mean growth r a t e Period of growth (week)  Dam l i n e  Sire line BA  MH  NH  UBC  BA  MH  NH  UBC  1-3  2.87ab  2.76 C  2.91a  2.85 b  2.87ab  2.78 C  2.913  2.83bC  3-7  2.22 a  2.09°  2.21 a  2.13 b  2.18 b  2.08°  2.16 b  1-7  2.44 a  2.31°  2.44 a  2.37 b  2.41 b  2.32°  2.22 a a 2.45  Hatch-3  2.56 a  2.53a  2.62 a  2.58 a  2.62 a  2.53 b  2.60 3  2.54 b  Hatch-7  2.37 a  2.28°  2.39 a  2.32 b  2.37 a  2.28°  2.39 a  2.32 b  2.38 b  Those means w i t h i n t h e same row o f each s i r e o r dam l i n e which c a r r y t h e same s u p e r s c r i p t are n o t s i g n i f i c a n t l y d i f f e r e n t (P > 0 . 0 5 ) .  TABLE 47. MEAN PRE- AND POST-STORAGE  EGG WEIGHTS FOR THE HATCHED PROGENY OF EACH SIRE AND DAM LINE  Mean egg w e i g h t (gm.) Sire Dam line  BA  MH  line NH  UBC  Mean  BA  54.25 (53.75)  55.78 ( 5 5 . 28)  54.50 (54.08)  55.95 (55.55)  55.12 (54. 6 6 ) °  MH  60.00 (59.50)  60.00 ( 5 9 . 60)  57.90 (57.42)  60.72 (60.22)  59.65 ( 5 9 . 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. 3 4 ) a l  Mean  57.68 ( 5 7 . 5 7 ) a b  58.07 (57. 6 1 ) a b  b 57.18 ( 5 6 . 7 0 )  58.65 ( 5 8 . 1 9 ) a  57.89 (57. 42)  ^ P o s t - s t o r a g e egg w e i g h t b r a c k e t e d . ' '  ' Those means w i t h i n t h e same row o r column f o r p r e - and p o s t - s t o r a g e egg w e i g h t s w h i c h c a r r y the same s u p e r s c r i p t a r e n o t s i g n i f i c a n t l y d i f f e r e n t (P > 0 . 0 5 ) .  - 98 -  order i n t e r a c t i o n s  o f the egg w e i g h t d a t a i s p r e s e n t e d i n T a b l e 4 8 , and i t  showed t h a t no s i g n i f i c a n t e f f e c t f o r any second o r d e r i n t e r a c t i o n s T h e r e f o r e , i t seemed r e a s o n a b l e t o p o o l t h e s e i n t e r a c t i o n s term.  existed.  i n t o an e r r o r  The a n a l y s e s o f v a r i a n c e o f mean egg w e i g h t s , t e s t i n g t h e s t o r a g e  effect within  each r e p l i c a t i o n , i s p r e s e n t e d i n T a b l e 4 9 , and i t showed t h e  s i g n i f i c a n t e f f e c t due t o s t o r a g e i n b o t h r e p l i c a t i o n s .  I t i s important to  n o t e t h a t t h e t o t a l v a r i a t i o n o f t h e egg w e i g h t s o f r e p l i c a t i o n 1 was h i g h e r than t h a t o f r e p l i c a t i o n 2: a p p r o x i m a t e l y  2-fold.  I t was c l e a r from t h e a n a l y s e s o f v a r i a n c e o f p r e - and p o s t - s t o r a g e egg w e i g h t s i n T a b l e 48 t h a t a l l o f t h e 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 t h e 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 a l s o s i g n i f i c a n t f o r b o t h p r e - and p o s t - s t o r a g e egg w e i g h t s . 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 t h e p r e - s t o r a g e egg w e i g h t b u t n o t s i g n i f i c a n t f o r t h e p o s t - s t o r a g e egg w e i g h t .  The s i r e and  dam l i n e mean egg w e i g h t s a r e p r e s e n t e d i n T a b l e 4 7 , and i t was found t h a t the BA dams w h i c h had t h e l o w e s t mean egg w e i g h 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 t h e MH and NH dams.  The MH dams, w i t h t h e h i g h e s t egg w e i g h t , 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 t h e NH dams.  The UBC dam egg w e i g h t was  n o t 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  t h e NH o r t h e MH dams, b u t was s i g -  nificantly different  The i n t e r e s t i n g  from the BA dams.  v a r i a t i o n w h i c h was s i g n i f i c a n t i n d i c a t e d  s i r e source of  t h a t t h e NH and t h e 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 e a c h 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 PREAND POST -STORAGE EGG WEIGHTS FOR HATCHED PROGENY  SS o f egg weight Source o f variation  d.f.  Sire  3  Dam  line line  3  S x D  9  Sex (F)  Pre-storage  * 18.67 186.88* •  *  Post-storage  * 19.48 185.36*  *  1  14.16 1.02  13.74 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  R e 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  S x D x R  9  0.92  F  1  1.86  1.96  x R  * *  7.31 0.96  S x F  x R .  3  0.95  1.03  D x F  x R  3  1.97  2.08  9  2.75  3.09  63  705.75  681.92  Residual  Total  -  Significant  (P _< 0.05).  * *  - 100 -  TABLE  49.  ANALYSES OF VARIANCE OF MEAN EGG WEIGHTS TESTING THE STORAGE EFFECT  Sums o f squares  Source o f variation  d.f.  Replication  1  Replication 2  S i r e l i n e (S)  3  13.81*  10.27*  Dam l i n e  3  138.89*  52.91*  S x D  9  9.22*  15.42*  Storage ( S t . )  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  31  163.26  . 81.09  (D)  Total  Significant  (P <_ 0.05).  - 101 -  weight,  but n e i t h e r were s i g n i f i c a n t l y d i f f e r e n t  sires.  These r e s u l t s  There was no obvious  from  the BA o r the MH  h e l d t r u e f o r both p r e - and p o s t - s t o r a g e egg w e i g h t s . evidence  t o e x p l a i n t h i s most i n t e r e s t i n g  can be s p e c u l a t e d t h a t the semen from f l u e n c e on egg s i z e and i t p o s s i b l y semen used o r p o s s i b l y  It  the 4 male l i n e s d i d e x e r t some i n -  c o u l d be a t t r i b u t a b l e  a chemical d i f f e r e n c e  The r e p l i c a t i o n e f f e c t  effect.  f o r egg weight  existed  to the volume of  i n the s e m i n a l  ( T a b l e 50) showed  fluid.  replication  2 had the s i g n i f i c a n t l y h i g h e r mean egg weight than r e p l i c a t i o n 1 by approxi m a t e l y 5.4 grams f o r p r e - s t o r a g e egg weight and 5.2 grams f o r p o s t - s t o r a g e egg weight. accounted The  The 7 week d i f f e r e n c e  f o r the l a r g e r  i n the age o f the dams i n r e p l i c a t i o n 2  egg weight and the more v a r i a t i o n  s i r e , dam and s i r e x dam i n t e r a c t i o n  effects  expressed  p r e - and p o s t - s t o r a g e egg weight are shown i n T a b l e 51. t h a t the p r i m a r y  s o u r c e s of s i g n i f i c a n c e  previously  noted.  as d e v i a t i o n s f o r  I t can be  concluded  o f the s i r e x dam i n t e r a c t i o n i n  b o t h p r e - and p o s t s t o r a g e egg weight was due to the NH s i r e s mated w i t h the MH dams i n c o n t r a s t w i t h the NH s i r e s mated w i t h the NH dams. gave an i n t e r a c t i o n tion effect  in this  o f -1.04 grams, w h i l e the l a t t e r gave an  o f 0.73 grams i n p r e - s t o r a g e egg weight.  t h a t the d i f f e r e n c e probably  effect  former interac-  The r e a d e r i s reminded  i n egg weight o f 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  the b a s i c c o n t r i b u t i n g study.  The  factor  i n producing r e p l i c a t i o n  differences  - 102 -  TABLE 50.  MEAN PRE- AND POST-STORAGE EGG WEIGHTS BY REPLICATION FOR HATCHED PROGENY  Mean egg weight  (gm.)  Replication 1  Replication 2  Mean  Pre-storage  55.49*  60.54  58.01  Post-storage  55.09*  60.00  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 from r e p l i c a t i o n 2.  different  TABLE  5 1 . SIRE, DAM AND SIRE x DAM INTERACTION EFFECTS ON THE PRE- AND POST-STORAGE EGG WEIGHTS  Sire line Dam line  BA  MH  NH  line  UBC  Dam line  0.07  -2.77  BA  -0.66  0.43  0.14  0.12  -2.76  BA  NH  UBC  Dam effect  BA  -0.66  0.47  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  -0.21  0.18  -0.72  0.76  0  -0.25  0.19  -0.72  0.77  0  Sire effect  0.10-  Sire : MH  Dam effect  Sire effect  - 104  Embryo  -  Correlations The  simple c o r r e l a t i o n s of 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 are presented i n Table 52. These c o r r e l a t i o n c o e f f i c i e n t 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 i n which the number of observations averaged about 170 p l i c a t i o n of every age of embryo studied.  i n each sex and  re-  The c o r r e l a t i o n s 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  f o r 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 i n c r e a s i n g l y  cant and p o s i t i v e at 16 and 18 days of incubation  signifi-  f o r 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 c o r r e l a t i o n s 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 s i g n i f i c a n c e at 14 days of incubation  the c o r r e l a t i o n increased at 18 days of incubation The  and  f o r both sexes.  same r e s u l t s (Table 52) were observed f o r the post-storage egg  weights correlated w i t h the embryo weights, w i t h the exception of the females i n r e p l i c a t i o n 2 which r e f l e c t e d 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 days of incubation  and again agreed with Deland (1965).  The  14  complete lack  of any i n d i c a t i o n of a c o r r e l a t i o n 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 A N D REPLICATION, CALCULATIONS BASED ON INDIVIDUAL DATA  Days of  Male  Days of incubation  Replication 1  Replication 2  Prestorage  Poststorage  (N)  6  -0.121  -0.094  8  -0.129  10  P restorage  Poststorage  (319)  -0.099  -0.069  (318)  -0.101  (172)  -0.030  <0.000  (195)  -0.020  -0.015  (173)  0.080  0.120  (207)  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)  18  0.267  0.286  (160)  8  0.001  0.029  (148)  -0.052  -Q.016  (147)  10  -0.012  0.025  (137)  -0.063  -0.024  (140)  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)  1  *  *  * 0.152 * 0.285  (N)  0.184*  (163)  0.311  (157)  *  6  Female  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 f u r t h e r l i n e b a s i s f o r the p o s t - s t o r a g e d a t a . BA l i n e was that  2 dam  inspection  0.59,  (-0.06), MH  of the UBC  and MH  data i n d i c a t e d  low body w e i g h t s .  f o r the MH  relationship  that  The d a t a was  (0.22).  This  ( r = <-0.00).  be  Further line  The  The  d i d not demonstrate a p o s i t i v e  l i n e s s t i l l m a i n t a i n the r e l a t i o n s h i p  w i t h t h i s o b s e r v a t i o n may  the  indicated  dams to i n c r e a s e t o 0.23.  subsequent a n a l y s e s i n d i c a t e d  embryo weight a t 18 days o f development.  of  2 embryos i n each dam  While a complete i n t e r p r e t a t i o n  }  dam  a n a l y s e d removing these embry-  dams i n c r e a s e d but s t i l l  from the a d j u s t e d d a t a t h e dam  c o r r e l a t i o n f o r the dam  (-0.26) and NH  showed the c o r r e l a t i o n f o r the UBC  correlation  and NH  The  of t h e d a t a on a  l i n e s d i d agree w i t h the male d a t a of r e p l i c a t i o n 2.  had e x t r e m e l y os and  UBC  inspection  cannot  that  be made  the BA,  between egg weight  f a i l u r e of the MH  the r e s u l t of sampling  errors.  UBC  and  l i n e to  The  overall  c o r r e l a t i o n of a l l progeny on the a d j u s t e d d a t a showed a c o r r e l a t i o n of Post-hatching The weights  s i m p l e c o r r e l a t i o n c o e f f i c i e n t s of p r e - and p o s t - s t o r a g e  w i t h c h i c k body weights  and growth r a t e s w i t h i n each sex and  These c a l c u l a t i o n s were based  data which had  and  736,  730,  780  751 degrees  t i o n c o e f f i c i e n t s between c h i c k body weights significant.  The  correlations  were the h i g h e s t .  on  egg replica-  individual  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 .  weights  0.18.  Correlations  t i o n are shown i n T a b l e 53.  and  agree  and  egg w e i g h t s  between body weights  The v a l u e s averaged  A l l of the  0.85  correla-  were p o s i t i v e  a t h a t c h and  f o r males and  egg  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.  Replication 1 Male PrePostd . f . 736  Chick weight (week)  C h i c k growth r a t e (week)  Average c h i c k growth r a t e (week)  Hatch 1 2 3 4 5 6 7 P e r i o d o f growth Hatch-1 1-2 2-3 3-4 4-5 5-6 6-7 1-3 3-7 1-7 Hatch-3 Hatch-7  Significant  (Pj<0.05).  Replication 2 Female  Male  PrePostd . f . 730  Female  PrePostd . f . 780 0 .901* 0 .395* 0 .362* 0 .294* 0 .234* 0 .206* 0 .164* 0 .159*  PrePostd . f . 731 0 .894* 0 . 388* 0 .336* 0 .286* 0 .243* 0 .220* 0 .199* 0 .174*  0 .887* 0 .393* 0 . 341* 0 .288* 0 .245* 0 .221* 0 . 200* 0 .175*  .829* .327* .334* .273* .245* .206* .183* .160*  0.910* 0.389* 0.356* 0 .290* 0.229* 0 .202* 0.160* 0.154*  -0.199* -0.134* -0-199* -0.120* -0-143* -0.078 -0.068  -0 .190* -o .138* -0 .205* -0 .122* -0 .148* -0 .082 -0 .077  -0.285* -0.139* -0-165* -0.176* -0.076 -0.141 0.001  -0 .273* -0 .141* -0 . 170* -0 .174* -0 .081 -0 .138* 0 .001  -0 -0 -0 -0 -0 -0 -0  .292* .169* .116* .135* .064 .069 .034  -0 .283* -0 .169* -0 .121* -o .136* -0 .066 -0 .072 -0 .034  -0.207* -0.157* -0.211* -0.434* -0.416*  -0 -0 -0 -0 -0  -0.197* -0.178* -0.240* -0.422* -0.415*  -0 -0 -0 -0 -0  -0 -0 -0 -0 -0  .177* .137* .198* .408* .374*  -0 -0 -0 -0 -0  0.870* 0.310* 0.295* 0.255* 0.212* 0.159* 0.139* 0.Ill*  0.863* 0.313* 0 .296* 0.254* 0.211* 0.158* 0.137* 0.108*  0.835* 0.322* 0.329* 0.270* 0.242* 0.205* 0.183* 0.162*  -0.224* -0.142* -0.141* -0.186* -0.208* -0.064 -0.130*  -0.217* -0.143* -0.146* -0.188* -0-211* -0 .067 -0.134*  -0.179* -0.225* -0.243* -0.407* -0.444*  -0.183* -0.229* -0.284* -0.404* -0.446*  0 0 0 0 0 0 0 0  .213* .164* .219* .429* .420*  .201* .177* .241* .414* .409*  .181* .140* .201* .402* .372*  - 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.  c r e a s e 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  This i n -  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 w e i g h t n o t e d i n T a b l e 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 t h a n 1/2 a t 1 week o f  age and c o n t i n u e d t o r e d u c e , a t a low r a t e , as the progeny became o l d e r u n t i l a t 7 weeks of age t h e c o r r e l a t i o n c o e f f i c i e n t s a v e r a g e d about 0.12 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, t h e s e  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 w h i c h c o u l d o n l y be d e t e r m i n e d l a r g e sample s i z e i n v o l v e d . body w e i g h t s  by  and  low the  The c o r r e l a t i o n s between egg w e i g h t s and w e e k l y  seem t o 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  (Wiley,  1950 b; Skoglund e_t a l . , 1952; T i n d e l and M o r r i s , 1964; and D e l a n d , 1965). P r e - s t o r a g e egg w e i g h t had h i g h e r c o r r e l a t i o n s than p o s t - s t o r a g e egg w e i g h t at h a t c h b u t p o s t - s t o r a g e egg w e i g h t had h i g h e r c o r r e l a t i o n s a t 1 week of age and they c o n t i n u e d t o have the h i g h e r c o r r e l a t i o n s t h a n t h e p r e - s t o r a g e egg w e i g h t f o r a t 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 w e i g h t s and c h i c k w e e k l y g r o w t h r a t e s were n e g a t i v e w i t h the e x c e p t i o n of p r e - and p o s t - s t o r a g e egg w e i g h t 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 w h i c h had v e r y positive correlation.  low  I n g e n e r a l , the c o r r e l a t i o n s were c o m p a r a t i v e l y  h i g h e r a t the e a r l i e r s t a g e s o f 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 w e e k l y growth r a t e s and egg  weights,  the growth p e r i o d H - l week gave the h i g h e s t v a l u e 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  u n d o u b t e d l y a r e m e a n i n g f u l the p r o p o r t i o n of v a r i a t i o n e x p l a i n e d was  not  g r e a t e r t h a n 7 p e r c e n t and as a consequence egg weight d i d n o t e x e r t a g r e a t i n f l u e n c e on weekly growth r a t e s . relationship  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  o f body w e i g h t a t h a t c h and egg w e i g h t i n t h a t 72 p e r c e n t , on  the a v e r a g e , of the v a r i a t i o n o f body w e i g h t c o u l d be a c c o u n t e d f o r by v a r i a t i o n i n egg s i z e a n d , a t 1 week of age t h i s r e l a t i o n s h i p  dropped t o 9  percent (Table 53). C o n s i d e r i n g 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 h i g h e r 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 o f 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 g r o w t h r a t e s w h i c h gave the c o r r e l a t i o n v a l u e s o f about  -0.42  i n both growth p e r i o d s .  tions  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 l o w e r  correlation.  T h i s was i n agreement between the 2 r e p l i c a -  These v a l u e s were p r o b a b l y due t o the h i g h s i m p l e c o r r e l a t i o n  found i n t h e h a t c h i n g w e i g h t (72 p e r c e n t + ) .  However, a l l of t h e s e c o r r e l a -  t i o n s were n e g a t i v e . The s i m p l e c o r r e l a t i o n s  between embryonic growth p e r i o d s and  chick  growth p e r i o d s f o r each sex by r e p l i c a t i o n a r e shown i n T a b l e 54,55, 56 and 57.  W h i l e a complete i n t e r p r e t a t i o n d i d n o t appear t o be e v i d e n t t h e r e were  some i n t e r e s t i n g r e s u l t s t h a t s h o u l d be c o n s i d e r e d . The 1-3 week growth r a t e f o r t h e males o f r e p l i c a t i o n 1 ( T a b l e 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) 8-10  C h i c k growth p e r i o d 1-3 -0.284  3-7  1-7  -0.065  -0.130  10-12  0.551*  0.330  0.428  12-14  -0.520*  -0.406  -0.468  14-16  0.565*  0.493*  0.534*  (week)  Hatch-3  Hatch-7  -0.236  -0.169  0.518* -0.439  0.502* -0.494*  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)  1-3  3-7  8-10  0.177  -0.533*  10-12  Chick growth  0.530* -  0.560*  1-7 -0.040 0.570*  period  (week) Hatch-3 0.040 0.437  i  Hatch-7 -0,037 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*  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  Significant  (P <_ 0.05).  0.505*  0.454  0.546*  - 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 period (day)  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  C h i c k growth p e r i o d  S i g n i f i c a n t (P <_ 0 . 0 5 ) .  (week)  - 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)  C h i c k growth p e r i o d 1-3  3-7  1-7  (week)  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*  -0.492*  -0.374  0.048  -0.307  -0.287  -0.208  0.123  -0.132  -0.522*  -0.415  -0.184  -0.409  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  8-12  -0.060  8-14  0.018  8-16  -0.163  8-18  Significant  (P_<0.05).  '  - 114 -  rates.  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 t h e 3-7 week growth r a t e .  A p p r o x i m a t e l y 28 p e r c e n t o f t h e  v a r i a t i o n i n 1-7 week1 growth r a t e c o u l d 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 s h o u l d be n o t e d t h a t a n e g a 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 e x i s t e d between t h e 12-14 day embryo growth r a t e and 1-3 week growth r a t e .  The r e a s o n f o r t h e n e g a t i v e v a l u e was n o t e v i d e n t and i t c o u l d  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 t h e 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 t h e 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 a g a i n a f a i r l y h i g h p r o p o r t i o n (over 25 percent)  o f 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 e x p l a i n e d  by v a r i a t i o n i n t h e s e embryo growth r a t e s . The r e l a t i o n s h i p of egg w e i g h t t o h a t c h i n g w e i g h t ( T a b l e 53) i n d i c a t e d t h a t h a t c h i n g w e i g h t was n o t a r e l i a b l e s t a r t i n g p o i n t t o measure growth rate since approximately  69-83 p e r c e n t of t h e v a r i a t i o n i n h a t c h i n g  weight  c o u l d 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 o f egg w e i g h t o v e r a l l sexes and replication tested.  A l s o i t was o b s e r v e d t h a t i n g e n e r a l t h e h i g h e s t , n e g a -  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 g r o w t h r a t e and egg w e i g h t , a l though o n l y 4-9 p e r c e n t o f t h e v a r i a t i o n c o u l d be a s s o c i a t e d w i t h t h e v a r i a t i o n i n egg w e i g h t .  The female progeny o f r e p l i c a t i o n 1 ( T a b l e 55) showed  a s l i g h t l y d i f f e r e n t r e s p o n s e i n t h a t o n l y t h e 10-12 day embryo g r o w t h 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 rate.  I n t h i s i n s t a n c e 32 p e r c e n t o f the v a r i a t i o n i n 1-7 week growth r a t e  c o u l d 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 -  r e a s o n f o r t h e s i g n i f i c a n t and n e g a t i v e 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 n o t a p p a r e n t , but when one c o n s i d e r e d t h e 8-12 day embryo growth r a t e a g a i n a p p r o x i m a t e l y 25 p e r c e n t 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 o f the c h i c k a f t e r 1 week of age.  I t would  appear  t h a t the p e r i o d s o f time o f e a r l y embryonic growth does have some s e x u a l dimorphism i n t h a t t h e 8-16 day embryo growth r a t e f o r m a l e s had t h e h i g h e r r e l a t i o n s h i p t o 1-3, 3-7 o r 1-7 week growth r a t e s , but i n t h e f e m a l e s i t was t h e 8-12 day p e r i o d t h a t showed the h i g h e r a s s o c i a t i o n .  T h i s should not  be u n e x p e c t e d s i n c e t h e f e m a l e s 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 , l o w e r w e e k l y growth r a t e t h a n the males ( T a b l e 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 v e r y l i t t l e e v i d e n c e i f any t o s u p p o r t the r e l a t i o n s h i p s u g g e s t e d f o r r e p l i c a t i o n 1.  However, the r e a d e r i s reminded t h a t t o t h i s p o i n t many d i f -  f e r e n c e s have been shown t o 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 e v e r y 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 w e i g h t s and growth r a t e s f o r b o t h embryo and c h i c k d a t a as w e l l as egg w e i g h t s .  This  f a i l u r e o f r e p l i c a t i o n 2 t o show agreement w i t h r e p l i c a t i o n 1 f o r t h e s i m p l e c o r r e l a t i o n s between embryo growth r a t e s and c h i c k growth r a t e s may be a n o t h e r r e f l e c t i o n o f t h e s e p r e v i o u s l y demonstrated d i f f e r e n c e s .  The male d a t a  of r e p l i c a t i o n 2 ( T a b l e 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 b e tween embryo growth r a t e and c h i c k growth r a t e .  The f e m a l e d a t a o f r e p l i c a -  t i o n 2 ( T a b l e 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 s i m p l e c o r r e l a t i o n b e tween the 16-18 day embryo growth r a t e and t h e growth r a t e s from 1-3,  3-7,  - 116 -  and 1-7 weeks.  A p p r o x i m a t e l y 4 9 , 25 and 36 p e r c e n t o f t h e v a r i a t i o n i n  16-18 day embryo growth r a t e o f t h e s e f e m a l e s was a s s o c i a t e d w i t h t h e s u b sequent performance a t 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 . Considering the simple c o r r e l a t i o n  o f egg w e i g h t w i t h embryo w e i g h t  ( T a b l e 52) t h e males o f r e p l i c a t i o n 1 and 2 showed a p o s i t i v e  association,  b u t t h e c o r r e l a t i o n o b t a i n e d f o r t h e females o f r e p l i c a t i o n 2 p r a c t i c a l l y d i s a p p e a r e d , whereas the f e m a l e s o f r e p l i c a t i o n 1 had a s t r o n g  relationship.  T a b l e 13 shows the mean embryo growth r a t e s f o r b o t h 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 m e a s u r a b l e .  The averaged -male and female embryo  growth r a t e f o r t h e s e 2 p e r i o d s were v e r y c l o s e ; 3.55 and 3.59 f o r t h e 14-16 day embryo growth r a t e , males and f e m a l e s , r e s p e c t i v e l y and 3.09 and 3.06 sex  f o r t h e two sexes a t the 16-18 day embryo growth r a t e .  Inspecting the  r e s p o n s e w i t h i n each r e p l i c a t i o n f o r t h e s e 2 p e r i o d s showed a h i g h e r  growth r a t e f o r males and f e m a l e s o f r e p l i c a t i o n 2 o v e r t h a t o f r e p l i c a t i o n 1 whereas p r i o r t o t h o s e p e r i o d s r e p l i c a t i o n 2 had t h e l o w e r embryo growth r a t e .  The r e a s o n f o r t h i s r e v e r s a l was not a p p a r e n t b u t t h e i n c r e a s e  i n growth r a t e o f r e p l i c a t i o n 2 over t h a t o f r e p l i c a t i o n 1 i n t h e 14-16 and 16-18 day embryo growth r a t e may w e l l be t h e consequence o f t h e 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 w e i g h t and embryo w e i g h t s a s w e l l as t h o s e o f the w e e k l y body w e i g h t s o f t h e p o s t - h a t c h d a t a a r e shown  - 117 -  i n T a b l e 58.  W h i l e t h e e s t i m a t e s of the a s s o c i a t e d v a r i a t i o n s  embryo w e i g h t s and 7-week body w e i g h t s was t h a t an e a r l y existed.  relationship  v a r i a b l e , i t was  between t h e  readily  between embryo w e i g h t s and 7-week body w e i g h t s  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  t i o n s t a r t i n g a t 12 days o f development i n r e p l i c a t i o n 1. this relationship  was  noted  correla-  In r e p l i c a t i o n 2  s i g n i f i c a n t a t 10 days o f i n c u b a t i o n f o r t h e males  and not u n t i l 14 days f o r t h e f e m a l e s .  A g e n e r a l i n c r e a s e f o r b o t h sexes  i n each r e p l i c a t i o n was n o t e d t h r o u g h o u t the embryonic d e v e l o p m e n t , w i t h the e x c e p t i o n of t h e female embryos o f r e p l i c a t i o n 1.  However, b o t h  sexes  i n each r e p l i c a t i o n had an average o f s l i g h t l y more t h a n 36 p e r c e n t o f the v a r i a t i o n i n 7-week body w e i g h t accounted f o r by v a r i a t i o n i n 16-day embryo body w e i g h t .  I n f a c t the v a l u e s averaged 9 , 32, 36 and 39 p e r c e n t f o r 1 2 ,  14, 16 and 18 d a y s , r e s p e c t i v e l y . same l e v e l o f a s s o c i a t i o n  I t was  most i n t e r e s t i n g  t o n o t e t h a t the  o f t h i s v a r i a b i l i t y d i d n o t r e - o c c u r i n the p o s t -  h a t c h e d c h i c k d a t a u n t i l t h e b i r d s were a t l e a s t 2 weeks of age, and a t t h a t time on the average 35 p e r c e n t of t h e v a r i a t i o n i n 7-week body w e i g h t c o u l d be a s s o c i a t e d w i t h a 2 week body w e i g h t . was  17 p e r c e n t . )  (At 1 week of age t h e average v a l u e  On t h e average o n l y 2 p e r c e n t of the v a r i a t i o n  i n 7-week body  w e i g h t c o u l d be a s s o c i a t e d w i t h h a t c h i n g w e i g h t , but as shown i n T a b l e 53 h a t c h i n g w e i g h t was cent).  s t r o n g l y a s s o c i a t e d w i t h egg w e i g h t ( a p p r o x i m a t e l y 78 p e r -  T h e r e f o r e , these r e l a t i o n s h i p s  would seem t o p r o v i d e a s t r o n g demon-  s t r a t i o n t h a t the h a t c h i n g p r o c e s s i n t e r r u p t s  the g e n e t i c a l l y  d e t e r m i n e d body  w e i g h t d i f f e r e n c e s o f embryos, and n o t 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  Replication 1  Replication 2  Replication 1  Replication 2  Embryo weight  6  0 .291  0 .423  0 .163  0 .393  (days of  incu  8  0 .085  0 .330  -0.163  0 .440  bation)  calcu  10  0 .063  0.619*  lations  based  12  0.500*  0 .389  diallel  14  0.122  0.769*  means  16  0.568*  0.663*  18  0.561*  0.638*  on cell  Chick weight (week)  calcu-  1  based  2  individual  3  lations on  Hatch  data  0.076*  3  *  0.372  *  0.581  *  *  0.514 0.436  0.266  *  0 . 772 0.648* 0.814*  *c 0.166 0.306*  *  *d 0.182  *  0.475 0.638*  0.781*  0.495 0.679*  0.839*  0.819*  0. 773 0.834*  *  5  0.938*  0.892*  0.920*  0.882*  6  0.979*  0.912*  0.970"  0.906*  7  1.000*  l.poo"  1.000*  1.000*  7 8 0 degrees  of freedom.  C  7 3 0 degrees  of freedom.  d  7 5 1 degrees  of freedom.  * Significant  0.650*  0 .522 0.291  0.280  4  o f freedom.  b  0.127 0.488*  *  0.752 0.861*  7 3 6 degrees  a  *b  0 .078  (P  <_ 0 . 0 5 ) .  JL.  - 119 -  c h i c k r e a d j u s t t o the a f o r e m e n t i o n e d r e l a t i o n s h i p .  T h i s means t h a t the growth  r a t e from H - l and 1-2 weeks were r e c o v e r y phases which were d i r e c t l y t e d t o egg s i z e d i f f e r e n c e s o f t h e dam. p r o p o r t i o n a l recovery occurred  rela-  I t i s t o be n o t e d t h a t t h e g r e a t e s t  i n t h e H - l week grov?th r a t e .  T h i s agreed  v e r y n i c e l y w i t h t h e i n t e r p r e t a t i o n o f B r a y and I t o n (1962) and D e l a n d (1965) . The c o r r e l a t i o n s o f 7-week body w e i g h t s w i t h embryo growth r a t e s and c h i c k growth r a t e s a r e p r e s e n t e d  i n T a b l e 5 9 . The c a l c u l a t i o n s o f t h e s e  c o r r e l a t i o n s between 7-week body w e i g h t s and embryo growth r a t e s were based on t h e d i a l l e l c e l l means, w h i l e t h e c o r r e l a t i o n between 7-week body w e i g h t s 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 t h e i n d i v i d u a l d a t a w i t h 736 and 780 degrees o f freedom f o r t h 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, and 730 and 751 degrees of freedom f o r t h e 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 . C o n s i d e r i n g t h e c o r r e l a t i o n s o f 7-week body w e i g h t s w i t h t h e embryo growth r a t e s , a g a i n , t h e s p o r a d i c p r e s e n c e o f n e g a t i v e s i g n s and t h e f l u c t u a t i o n o f t h e v a l u e s among t h e t i o n s made i t d i f f i c u l t  2  sexes and r e p l i c a -  t o draw any m e a n i n g f u l i n t e r p r e t a t i o n .  However, t h e  l a c k o f 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 o f t h e independence o f the embryonic growth r a t e s f r o m 7-week body w e i g h t .  Those s i g n i f i c a n t  l a t i o n s t h a t appeared may be due to a chance r e l a t i o n s h i p . would e x p e c t no r e l a t i o n s h i p based on t h e growth r a t e m o d e l .  corre-  I n f a c t one I n contrast the  w e e k l y growth r a t e s a l l showed a l o w , 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 w e i g h t .  T h i s o f c o u r s e c o u l d be e x p l a i n e d b i o l o g i c a l l y when t h e  - 120 T A B L E 59. S I M P L E CORRELATION C O E F F I C I E N T S OF 7 WEEK BODY WEIGHTS WITH EMBRYO GROWTH RATES AND CHICK GROWTH RATES WITHIN EACH SEX AND R E P L I C A T I O N  7 Week b o  weight Female  Male Replication 1 Embryo g r o w t h period (days of incubation) calculations b a s e d on diallel cell means  Chick period  growth (week)  calculations b a s e d on individual data  Replication 2  Replication 1  8-10 10-12 12-14 14-16 16-18  -0.070 0.460 -0.435 0.507* -0.069  0.503* -0.367 0.364 0.553* 0.110  8-12 8-14 8-16 8-18  0.424 -0.074 0.640* 0.343  -0.033 0.453 -0.130 -0.023  0.730* 0.300 0.353 0.352  10-14 10-16 10-18  -0.024 0.560* 0.360  0.057 -0.391 -0.231  0.102 0.268 0.234  0.302 0.014 0.404  12-16 12-18  0.144 0.090  -0.095 0.012  -o.no -0.067  0.076 0.488  14-18  0.458  -0.343  0.179  0.184  Hatch-1  1-2 2-3 3-4 4-5 5-6 6-7 1-3 3-7 1-7 Hatch-3 Hatch-7  0.325* 0.202* 0.313* 0.155* 0.148* 0.246* 0.176*  3  0.318* 0.279* 0.352* 0.648* 0.644*  3 ^736 d e g r e e s o f f r e e d o m . 780 d e g r e e s o f f r e e d o m . *Significant  0.218 0.518 -0.284 0.147 0.037  Replication 2  0.394* 0.210 0.279* 0.080* 0.210* 0.054 0.310*  b  0.316* 0.370* 0.451* 0.619* 0.698*  0.204* 0.170* 0.288* 0.222* 0.193* 0.159* 0.225* 0.283* 0.303* 0.347* 0.518* 0.598*  -0.278 -0.055 0.368 0.384 -0.560* -0.290 -0.016 -0.274 0.097  C  0.336* 0.263* 0.292* 0.114* 0.188* 0.081* 0.328* 0.347* 0.403* 0.490* 0.591* 0. 708*  C d ^ O degrees o f freedom. 751 d e g r e s s o f f r e e d o m . (P <  0.05).  - 121 -  environment e x e r t s an i n f l u e n c e on growth w h i c h would be e x p e c t e d t o be r e f l e c t e d i n 7-week body w e i g h t .  Hatched c h i c k s a r e s u b j e c t e d t o more and  v a r i e d e n v i r o n m e n t a l d i f f e r e n c e s a f t e r h a t c h i n g than t h e embryos a r e when d e v e l o p i n g w i t h i n an i n c u b a t o r .  F o r example t h e p r e v i o u s l y demonstrated  r e c o v e r i n g phase o f t h e growth r a t e H - l week o f age on t h e average showed 10 p e r c e n t o f the v a r i a t i o n i n 7-week body w e i g h t c a n be r e l a t e d t o v a r i a t i o n f o r t h a t p a r t i c u l a r weeks g r o w t h .  The 1-2 week g r o w t h r a t e showed on  the average o n l y 5 p e r c e n t w h i l e t h e 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 t h e a v e r a g e s were 2, 3 and  2 percent, respectively.  I t was o f i n t e r e s t t o n o t e t h a t on t h e average 7  p e r c e n t o f t h e v a r i a b i l i t y i n 7-week body w e i g h t c o u l d be a s s o c i a t e d w i t h t h e v a r i a b i l i t y o f 6-7 week growth r a t e .  T h i s became more m e a n i n g f u l when  i t i s r e c a l l e d t h a t t h e growth r a t e v a l u e s 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 t h e c o r r e s p o n d i n g growth p e r i o d s were 2.19 and 1.58, r e s p e c t i v e l y (Table 3 5 ) .  T h i s d e p r e s s e d 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  reflec-  t e d i n t h e average p e r c e n t v a r i a t i o n o f 7-week body w e i g h t o f r e p l i c a t i o n 2, i n t h a t 10 p e r c e n t o f t h e v a r i a t i o n c o u l d be e x p l a i n e d .  In contrast, only  4 p e r c e n t c o u l d be a s s o c i a t e d w i t h t h e 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 n o t c o m p l e t e l y f i t  t h e model o f independence between  growth r a t e and body w e i g h t , growth r a t e c e r t a i n l y t a k e s i n t o a c c o u n t , i n a p r e c i s e f a s h i o n , t h e e n v i r o n m e n t a l 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 o f the i n f l u e n c e o f t h e s e e n v i r o n m e n t s .  - 122 -  The 1-3; 3-7 a s w e l l as t h e 1-7 week growth r a t e s showed on t h e average 1 0 , 12 and 17 p e r c e n t o f t h e v a r i a t i o n i n 7-week body w e i g h t c o u l d 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 t h e s e 3 t r a i t s , r e s p e c t i v e l y ( T a b l e 5 9 ) . S i n c e no comparable d a t a e x i s t s i n t h e l i t e r a t u r e s f o r t h e s e v a l u e s i t would be d i f f i c u l t t o say i f they a r e t o o h i g h o r w i t h i n a r a n g e t h a t was reasonable.  I t s h o u l d be n o t e d t h a t a g a i n 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 of  associated v a r i a b i l i t y  showed about 15 p e r c e n t and 22 p e r c e n t  w i t h 7-week body w e i g h t s w h i c h 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 t h e same r e s p e c t i v e p e r i o d s : . 8 and 12 p e r c e n t . The  a d v e r s e e f f e c t o f H - l week growth r a t e , as a consequence o f t h e  egg s i z e r e l a t i o n s h i p , was a g a i n demonstrated  when on t h e average 36 p e r c e n t  (H-3 week growth r a t e ) and 44 p e r c e n t (H-7 week growth r a t e ) o f t h e v a r i a t i o n was accounted  f o r between t h e s e v a r i a b l e s and 7-week body w e i g h t .  So t h e  a d d i t i o n o f h a t c h i n g w e i g h t t o t h e growth r a t e v a l u e would appear t o be d e t r i m e n t a l t o the i n t e n t o f m i n i m i z i n g t h e c o r r e l a t i o n s between growth r a t e and body w e i g h t . M u l t i p l e L i n e a r R e g r e s s i o n s o f 7-Week Body Weights 2 T a b l e 60 p r e s e n t s t h e c o e f f i c i e n t s o f d e t e r m i n a t i o n (R ) as a p e r c e n t of  t h e m u l t i p l e l i n e a r r e g r e s s i o n o f 7-week body w e i g h t , w i t h i n each s e x and 2  r e p l i c a t i o n , r e g r e s s e d 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 indicate  the p e r c e n t a g e o f t h e v a r i a t i o n o f 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  r e g r e s s e d independent  variables.  v a r i a b l e s i n t h i s s t u d y were d i v i d e d i n t o 2 g r o u p s .  i  i  The s e l e c t e d  The f i r s t t e s t e d group  TABLE 6 0 .  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 w e i g h t Replication 1  Selected t r a i t s Hatch w e i g h t  Hatch-3  3-7  + + + +  +  +  + + +  1 Week w e i g h t + + + +  1-3  3-7  +  +  + +  +  + +  Female d.f.730  Male d.f.-780  Female d.f.-751  91.4 66.6 65.1 10.0 52.6 0.6 42.0 7.8 41.5  89.6 61.7 56.4 13.8 42 2 26 9 33.2  92.8 75.6 63.0 17.7 54.9 1.6 38.3 13.7 50.2  92.8 75.0 62 21 55 3 35.0 16.2 47.9  97.2 92.8 65.1 50.3 12.9 13.8 10.1 7.8 11.7  96.6 91.2 57.3 48.1 12.1 9.4 8.0 9.2 10.5  97.7 92.9 63.3 57.8 20.3 23.8 10.0 13.7 22.3  97.6 93.3 62.0 59.,3 24..3 22..6 12..1 16..2 22.,1  1-7  +  +  Male d.f.-736 Hatch-7  + + +  Replication 2  - 124 -  was h a t c h w e i g h t , H-3 week g r o w t h 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 w e i g h t , 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 . for  The r  values  t h e s i n g l e t r a i t s r e l a t e d t o 7-week body w e i g h t have been c o m p l e t e l y  d i s c u s s e d p r e v i o u s l y as r e l a t e d t o T a b l e 58 and 5 9 . They a r e p r e s e n t e d i n T a b l e 60 f o r t h e r e a d e r s ' c o n v e n i e n c e i n r e f e r r i n g t o t h e m u l t i p l e regression  linear  analyses.  The 3 t r a i t s ; 1-week body w e i g h t , 1-3 week growth r a t e and 3-7 week growth r a t e , e x p l a i n e d on t h e average o v e r 97 p e r c e n t o f t h e v a r i a t i o n i n 7-week body w e i g h t . (1965),  T h i s h i g h p e r c e n t a g e was i n good agreement w i t h R o b e r t s  S t a l e y et_ a l _ . (1970) and Deland ( 1 9 6 5 ) .  U s i n g 1-week body w e i g h t  and 1-7 week growth r a t e about 92 p e r c e n t o f t h e a s s o c i a t e d v a r i a t i o n was explained.  U s i n g h a t c h i n g w e i g h t and i t s a s s o c i a t e d growth r a t e s showed t h a t  l e s s v a r i a t i o n was e x p l a i n e d f o r e a c h o f t h e above analogous s i t u a t i o n s 92 and 70 p e r c e n t , r e s p e c t i v e l y .  about  T h e r e f o r e t h e use o f h a t c h i n g w e i g h t i n  c a l c u l a t i n g growth r a t e v a l u e and s u b s e q u e n t l y u s i n g i t i n a m u l t i p l e  linear  r e g r e s s i o n a n a l y s e s would n o t be as e f f e c t i v e as u s i n g 1-weekbody w e i g h t 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 t o n o t e t h a t t h e o b v i o u s  r e p l i c a t i o n e f f e c t shown i n many p r e v i o u s a n a l y s e s was n o t a p p a r e n t i n t h e 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 u s i n g 1-week body w e i g h t , 1-3 week growth r a t e and 3-7 week growth r a t e o r was i t found when 1-7 week growth r a t e was used as t h e second independent v a r i a b l e .  There were r e p l i c a t i o n  differences  - 125 -  n o t e d when h a t c h i n g w e i g h t was i n c o r p o r a t e d i n t o t h e growth r a t e a n a l y s i s . The e f f e c t o f 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 t h e v a r i a t i o n of  7-week body w e i g h t was noted i n t h a t on t h e average 1-week body w e i g h t  and 1-3 week growth r a t e a c c o u n t e d f o r 62 p e r c e n t o f t h e v a r i a t i o n i n 7-week body w e i g h t .  Where as 1-week body w e i g h t and 3-7 week growth r a t e showed  a l o w e r v a l u e o f 54 p e r c e n t .  T h i s s u b s t a n t i a l l y agrees w i t h t h e d a t a o f  S t a l e y (1970) and R o b e r t s (1965) and s t r o n g l y s u g g e s t s t h a t the e a r l y  growth  p e r i o d s have t h e most i m p o r t a n t i n f l u e n c e on t h e v a r i a t i o n o f 7-week body weight. W h i l e t h e v a r i a b i l i t y o f i n d i v i d u a l h a t c h i n g w e i g h t 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 w e i g h t , r  averaged 0.85 and 0.90 f o r  b o t h 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 ( T a b l e 5 3 ) , i t would be o f i n t e r e s t t o see i f any f u r t h e r v a r i a t i o n i n h a t c h i n g w e i g h t c o u l d be ex2 p l a i n e d by u s i n g the embryonic d a t a . v a r i o u s embryonic d a t a m u l t i p l e  T a b l e 61 shows t h e p e r c e n t R  r e g r e s s e d on h a t c h i n g w e i g h t .  used f o r a n a l y s i s were the a p p r o p r i a t e m a t i n g c e l l means.  for  The d a t a  On the a v e r a g e ,  o v e r t h e 2 r e p l i c a t i o n s , 90 and 86 p e r c e n t o f the v a r i a t i o n i n h a t c h i n g w e i g h t of males and f e m a l e s , r e s p e c t i v e l y , c o u l d 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 o f p r e - s t o r a g e egg w e i g h t , 8 day embryo w e i g h t and a l l o f the e a r l y growth r a t e p e r i o d s .  When p o s t - s t o r a g e egg w e i g h t was  f o r p r e - s t o r a g e egg w e i g h t no a p p r e c i a b l e change was e v i d e n t .  substituted Using e i t h e r  8-16 o r 8-18 day embryo growth r a t e and 8 day embryo w e i g h t w i t h p r e - and  TABLE 6 1 .  COEFFICIENTS OF DETERMINATION (100 x R 2 ) OF HATCHING WEIGHTS MULTIPLE REGRESSED ON SELECTED TRAITS  Selected  traits CN  xi00  CO  >.  Ha  •H  cd 00  o rH 1  00  to >>  CO  >.  CO  CD  >1  >i  cd ^}  cd  cd T3  cd id  CN  <r rH  VO  00 rH  o rH  CN  <t  VO rH  rH 1  1  i-l  rH 1  rH  1  CO  cn  >N  >i  cd T3 VO  rH 1 00  cd  00 rH  1  00  00 cd M' O  4-1 W  I  <U r-l  P-l  OJ OO  cd u o  u  CO  I  •u  H a t c h i n g Weight Replication 1  Replication 2  Male  Female  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  40.5  0.0  2.5  80.6  70.1  70.6  87.3  CD  o  CM  +  +• +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  + + + +  + + +  + +  P r e - s t o r a g e egg w e i g h t . P o s t - s t o r a g e egg w e i g h t .  OV  - 127 -  p o s t - s t o r a g e egg w e i g h t d i d not g i v e any or p o s t - s t o r a g e egg w e i g h t a l o n e .  greater v a l u e s than u s i n g p r e -  P o s t - s t o r a g e egg w e i g h t showed an  2 average R  of  76 and 79 p e r c e n t f o r males and f e m a l e s , r e s p e c t i v e l y .  It  would appear t h a t h a t c h i n g w e i g h t i s , as i n d i c a t e d p r e v i o u s l y , a l m o s t comp l e t e l y a s s o c i a t e d w i t h egg w e i g h t and the e f f e c t s o f 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 h a t c h e d c h i c k .  The analogous d a t a t o  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 w e i g h t can be e x p l a i n e d by v a r i a t i o n i n embryonic growth i s shown i n T a b l e 62.  An average o f 90 and  86 p e r c e n t f o r males and f e m a l e s of 1-week body w e i g h t v a r i a t i o n c o u l d be e x p l a i n e d by u s i n g 8 day embryo body w e i g h t and a l l embryonic growth p e r i o d s as w e l l as u s i n g p o s t - s t o r a g e egg w e i g h t and H - l week growth r a t e .  By  de-  l e t i n g 8 day embryo w e i g h t the p e r c e n t a g e v a l u e d i d not a p p r e c i a b l e change. A p p r o x i m a t e l y 83 and 80 p e r c e n t of the v a r i a t i o n i n 1-week body w e i g h t f o r male and female p r o g e n y , r e s p e c t i v e l y , c o u l d be accounted f o r u s i n g 8-16  day  embryo growth r a t e a l o n g w i t h p o s t - s t o r a g e egg w e i g h t and H - l week growth rate.  I n f a c t t h e l a t t e r 2 t r a i t s by t h e m s e l v e s on the average accounted f o r  80 p e r c e n t of the v a r i a t i o n i n 1-week body w e i g h t .  But e i t h e r t r a i t a l o n e  d i d not exceed 50 p e r c e n t (and on the average f a r l e s s ) , w i t h i n any sex and replication.  W h i l e n o t shown i t s h o u l d be apparent t h a t 100 p e r c e n t o f 1  week body w e i g h t v a r i a t i o n would be a c c o u n t e d f o r by u s i n g h a t c h i n g w e i g h t 2 and H - l week growth r a t e .  I t would seem t h a t the h i g h R  v a l u e of 80 p e r c e n t  o b t a i n e d u s i n g p o s t - s t o r a g e egg w e i g h t and h a t c h i n g w e i g h t i s due t o the c o r r e l a t i o n between egg w e i g h t and h a t c h i n g w e i g h t .  A g a i n 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  Selected  traits  4J  Xi 00 •H CD  >.  cd X) 00  +  co >N  cd Xl  o rH 1  00  +  to  >> cd X)  CN rH  I o  rH  +  CO  to  to  cd XI  cd X)  cd X)  <r  vO rH  00  <r rH  VO rH  >1  rH t CN rH  +  >. 1  +  H 1  to  cd >.  X)  4J CO  VO rH  00 rH  4J  00  00  1  + +  +  +  +  u o  cd X)  +  +  to  0) 00 cd  + +  1  I  to o p-l  1-week body weight  CN rH  1 X o 4J  Replication 1  Replication 2  cd  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  + +  P o s t - s t o r a g e egg w e i g h t . Hatch-1 week growth r a t e .  - 129 -  embryonic growth a r e somewhat masked b u t some o f t h e i r i n f l u e n c e s on 1 week body w e i g h t c o u l d be o b s e r v e d . Heritability Based on many p r i o r a n a l y s e s arguments were made f o r s e p a r a t i n g t h e 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 t h r o u g h o u t t h i s r e p o r t s u g g e s t s t h a t f o r t h e h e r i t a b i l i t y  esti-  mates i t would be a d v i s a b l e t o i n s p e c t t h e s e e s t i m a t e s 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 s e x . In  g e n e r a l , the h e r i t a b i l i t y e s t i m a t e s of embryo w e i g h t s ( T a b l e 63)  2 based on the s i r e component o f v a r i a n c e (h ) were v e r y l o w ( l e s s t h a n 0 . 0 1 ) , f o r male and female progeny o f b o t h r e p l i c a t i o n s 1 and 2. gative h  2  e s t i m a t e s were s m a l l and rounded t o z e r o .  R e c a l l t h a t ne-  The h  2  based on t h e dam  2 2 ponent o f v a r i a n c e (h^) was g e n e r a l l y much h i g h e r and on t h e average h ^ for  t h e male progeny ranged from 0.14 (18 day embryo w e i g h t ) t o 0.68 (8 day  embryo w e i g h t ) .  The s i m i l a r comparisons f o r t h e female progeny ranged from  0.15 (14 day embryo w e i g h t ) t o 0.53 (8 day embryo w e i g h t ) .  This higher  esti-  2 2 mate f o r h , over t h a t o f h would be e x p e c t e d i n t h a t the comparable body d s w e i g h t a n a l y s e s , T a b l e 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 general, this  2 t y p e of d i f f e r e n c e i n the h  e s t i m a t e s would i n d i c a t e a h i g h p r o p o r t i o n o f  m a t e r n a l 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 w e i g h t s .  These m a t e r n a l  e f f e c t s were s u g g e s t e d as b e i n g a t t r i b u t a b l e t o n u t r i t i o n a l e n v i r o n m e n t a l d i f f e r e n c e s w i t h i n the eggs o f t h e d i f f e r e n t dam l i n e s .  W h i l e t h i s argument  TABLE  6 3 . HERITABILITY ESTIMATES OF EMBRYO WEIGHTS, CALCULATIONS BASED ON SEPARATED SEX IN EACH REPLICATION  Replication 1 Days o f incubation  Male  Replication 2  Female  >  2  61  0.00  0.36  8  0.00  0.39  0.00  10  0.00  0.20  12  0.00  14  Male  -2  >  Female  N  2  2  0.00  0.60  0.65  0.07  0.97  0.24  0.57  0.40  0.00  0.55  0.45  0.18  0.50  0.00  0.01  0.18  0.00  0.00  16  0.03  0.14  0.00  18  0.00  0.00  0.00  6 day embryos n o t s e x e d .  Mean Male  h  D  h  Female  -  s  2  0.00  0.48  0.42  0.00  0.68  0.12  0.53  0.03  0.25  0.00  0.37  0.30  0.32  0.31  0.00  0.25 '  0.00  0.38  0-08  0.37  0.00  0.72  0.00  0.37  0.00  0.45  0.00  0.15  0.48  0.10  0.24  0.00  0.04  0.06  0.19  0.00  0.26  0.36  0.01  0.30  0.05  0.46  0.00  0.14  0.00  0.41  - 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 s t u d y i n developmental g e n e t i c s . 2  2  The h^ and h^ and t h e i r s t a n d a r d e r r o r s (S.E.) of t h e egg  weights,  c h i c k growth r a t e s and c h i c k body w e i g h t s 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 a r e p r e s e n t e d f o r t h e r e a d e r s ' i n s p e c t i o n i n T a b l e 64  (replica-  t i o n 1) and 65 ( r e p l i c a t i o n 2 ) . and  The  averaged r e p l i c a t e d v a l u e s f o r male 2  female progeny a r e shown i n T a b l e 66.  A l l n e g a t i v e v a l u e s of h  e s t i m a t e s found i n t h i s s t u d y were assumed t o be z e r o , t h e r e f o r e no t i v e v a l u e s appear i n the a f o r e m e n t i o n e d  nega-  tables. 2  A number of p r e v i o u s i n v e s t i g a t o r s have made e s t i m a t e s of h weight.  The  summary of t h e s e by S h o f f n e r and  S l o a n (1948) as c i t e d  of  egg  by  L e r n e r and Cruden (1951) i n d i c a t e d t h a t the range of e s t i m a t e s was f r o m 0.46 2 t o 0.84. I n t h e p r e s e n t s t u d y , t h e average h e s t i m a t e s o f p r e - and p o s t 2 2 s t o r a g e egg w e i g h t s , (h + h ^ ) / 2 , were found t o be 0.42 f o r b o t h male and 2 female p r o g e n y .  The h g averaged f o r the 2 r e p l i c a t i o n s was  c o n s i s t e n t f o r the male and female p r o g e n y . than those r e p o r t e d i n the l i t e r a t u r e .  0.07.  This  was  T h i s e s t i m a t e was much lower  The low e s t i m a t e s m i g h t be due, a t  l e a s t i n p a r t , to t h e f a c t t h a t t h e 4 l i n e s o f c h i c k e n s s t u d i e d a r e n o t c o m p l e t e l y 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 m i n i m i z e d w i t h i n the s i r e l i n e component o f v a r i a n c e 2 2 w h i c h would g i v e a lower e s t i m a t e of h . The v e r y h i g h h ^ e s t i m a t e s of p r e and p o s t - s t o r a g e egg w e i g h t s (0.84) presumably r e f l e c t e d a m a t e r n a l e f f e c t on egg w e i g h t s . The e s t i m a t e of the m a t e r n a l 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 Trait P r e - s t o r a g e egg w e i g h t P o s t - s t o r a g e egg w e i g h t Hatch-1 week G.R.1 1-2 week G.R. 2-3 week G.R. 3-4 week G.R. 4-5 week G.R. 5-6 week G.R. 6-7 week G.R. 1-3 week G.R. 3-7 week G.R. 1-7 week G.R. Hatch-3 week G.R. Hatch-7 week G.R. Hatching weight 1-week body w e i g h t 2-week body w e i g h t 3-week body w e i g h t 4-week body weight 5-week body w e i g h t 6-week body w e i g h t 7-week body w e i g h t  Growth r a t e .  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 d  Female  h 2s  (S.E.)  h^  (S.E.)  10 10 00 12 21 31 37 06 24 24 49 55 20 81 25 09 01 00 03 10 17 29  (0.08) (0.08) (0.00) (0.10) (0.17) (0.24) (0.28) (0.05) (0.20) (0.20) (0.36) (0.40) (0.16) (0.54) (0.20) (0.08) (0.00) (0.00) (0.04) (0.08) (0.14) (0.23)  1.00 1.00 0 . 00 0 . 17 0. 37 0. 29 0. 27 0. 17 o;21 0. 37 o.52 o.67 0. 57 l . 00 0.99 0.09 0. 00 0.00 0. 12 0. 31 0. 45 0. 61  (0.62) (0.62) (0.00) (0.14) (0.28) (0.23) (0.21) (0.14) (0.17) (0.28) (0.38) (0.46) (0.44) (0.62) (0.62) (0.08) (0.00) (0.00) (0.10) (0.24) (0.33) (0.43)  0. 02 0 . 02 0 . 06 0 . 09 0 . 48 0. 43 0. 44 0 . 40 0 . 47 0. 41 o.99 o.97 0 . 07 1.00 0.02 0. 26 0. 19 0.05 0.05 0.09 0. 23 0. 41  (S.E.)  hj  (S.E.)  (0.00) (0.00) (0.05) (0.08) (0.36) (0.32) (0.33) (0.30) (0.35) (0.31) (0.62) (0.61) (0.06) (0.62) (0.00) (0.21) (0.16) (0.04) (0.04) (0.08) (0.19) (0.31)  1.00 1.00 0 .07 0 . 08 0. 46 0. 42 0. 34 0.18 0. 41 0. 39 0. 78 0. 84 0. 25 1.00 0. 74 0. 18 0.08 0.03 0.08 0. 25 0. 39 0. 57  (0.62) (0.62) (0.06) (0.08) (0.34)  (0.32) (0.26)  (0.15) (0.31) (0.29) (0.52) (0.55) (0.20) (0.62) (0.50) (0.15) (0.08) (0.00) (0.08) (0.20) (0.29) (0,41)  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 (S .E.)  Trait P r e - s t o r a g e egg w e i g h t P o s t - s t o r a g e egg w e i g h t Hatch-1 week G.R. 1-2 week G.R. 2-3 week G.R. 3-4 week G.R. 4-5 week G.R. 5-6 week G.R. 6-7 week G.R. 1-3 week G.R. 3-7 week G.R. 1-7 week G.R. Hatch-3 week G.R. Hatch-7 week G.R. Hatching weight 1-week body w e i g h t 2-week body w e i g h t 3-week body w e i g h t 4-week body w e i g h t 5-week body w e i g h t 6-week body w e i g h t 7-week body w e i g h t  Growth r a t e .  Female  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  .04 .04 .00 .13 .20 .12 .11 .05 .07 .30 .21 .41 .15 .50 07 00 00 00 05 15 28 34  .04) .04) .00) .10) .16) .10) .09) .05) .06) (0 .24) (0 .16) (0 .31) (0 .13) (0 .37) (0 .06) (0 .00) (0 .00) (0 .00) (0 .05) (0 .13) (0 .22) (0 .26)  (0 (0 (0 (0 (0 (0 (0 (0 (0  (S.E.) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  .40 .38 .09 00 .11 16 16 .17 00 .08 12 .20 26 42 29 00 00 06 22 37 55 43  (0 .30) (0 .29) (0 .08) (0 .00) (0 .09) (0 • 13) (0 .13) (0 .14) (0 .00) (0 .08) (0 .10) (0 .16) (0 .21) (0 .32) (0 .23) ' (0.00) (0 .00) (0 .05) (0 .18) (0 .28) (0 .40) (0 .32)  h  s  (S.E.)  0 .12 (0 10) 0 .12 (0 10) 0 .01 (0 .00) 0 .20 (0 16) 0 .19 (0 16) 0 .30 (0 22) 0 .03 (0 04) (0 20) 0 .24 (0 00) 0 .00 (0 22) 0 .29 (0 30) 0 .40 (0 38) 0 .52 (0 25) 0 .35 (0 45) 0 .65 (0 10) 0 .12 0 .05 ' (0 04) 0 .12 (0 10) 0 .21 (0 16) (0 22) 0 .28 0 .29 (Q 22) (0 28) 0 .38 (0 30) 0 .41  -2 0 .69 0 .68 0 .08 ]0 .00 0 .16 0 .23 0 .11 0 .18 0 .01 0 .10 0 .38 0 .43 0 .35 0 .73 0 .54 0 .01 0 .00 0 .09 0 .25 0 .39 0 .55 0 .54  (S .E.) (0 (0 (0 (0 (0 (0 (0 (0 (0 (0 (0 (0 (0 (0 (0  .47) .47) .08) .00) .13) .19) .09) • 15) .00) .08) .29) .32) • 27) .49) 38) (0 00) (0 00) (0 .08) (0 20) (0 30) (0 40) (0 39)  - 134 T A B L E 66. H E R I T A B I L I T Y E S T I M A T E S OF EGG WEIGHT, GHICK GROWTH RATES AND BODY WEIGHTS, CALCULATIONS BASED ON THE AVERAGES ACROSS R E P L I C A T I O N S  Male  Trait  h  2 g  Female  h  2 D  h  2 s  h  2 D  0.07  0. 70  0.07  0.84  0.07  0.69  0.07  0.84  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  Pre-storage  egg weight  Post-storage Hatching  egg weight  weight  growth  rate  0.00  0.02  0.03  0.07  1-2 Week g r o w t h  rate  0.12  0.08  0.14  0.04  2-3 Week g r o w t h  rate  0.20  0.24  0.33  0.31  3-4 Week g r o w t h  rate  0.21  .0.22  0.36  0.32  4-5 Week g r o w t h  rate  0.24  0.21  0.23  0.22  5-6 Week  growth  rate  0.05  0.17  0.32  0.18  6-7 Week g r o w t h  rate  0.15  0.10  0.22  0.21  1-3 Week g r o w t h  rate  0.27  0.22  0.35  0.24  3-7 Week g r o w t h  rate  0.35  0.32  0.69  0.58  1-7 Week  rate  0.48  0.43  0.74  0.63  H-l  Week  growth  - 135  -  minus the s i r e v a r i a n c e component e x p r e s s e d the v a r i a n c e components the average, The  ( a f t e r Mover, C o l l i n s  and  Skoglund,  1962)  of  was  on  0.205. averaged body w e i g h t h  2  estimates 2  showed t h a t f o r h a t c h i n g weight the h^ than h  as a f r a c t i o n of the sum  across r e p l i c a t i o n s  (0.64) f o r both sexes was  (Table 66 much h i g h e r  2  (males: 0.06 and females: 0.07). The l a r g e m a t e r n a l e f f e c t ( t h a t of s egg weight) was reduced c o n s i d e r a b l y , and i t may have been minimum a t 1 week of age:  2 h , = 0.02 d  tively.  The body w e i g h t h  2 h , = 0.02 d  and 0.09:  and 0.09,  a maternal  2  h  2 = 0.01 s  estimates  males and  females  males and  a t 2 weeks of age h  2 g  females = 0.00  respecand  r e s p e c t i v e l y , showed no e v i d e n c e  0.15; of  effect.  The  2 r e d u c t i o n i n the h , e s t i m a t e s d  f o l l o w s t h a t n o t e d i n the c o r r e l a t i o n weight  and 0.15,  ( T a b l e 53).  f o r h a t c h , 1 and  2 weeks o f  a n a l y s e s between egg w e i g h t and  age chick  I t would appear t h a t t h i s s t r o n g r e l a t i o n s h i p between 2  egg w e i g h t and e a r l y hatch  and  c h i c k w e i g h t i n f l u e n c e d the h  a t 1 week of  I t was  age.  o f extreme i n t e r e s t  to note  e s t i m a t e s t a r t i n g a t 4 weeks of age c r e a s i n g v a l u e was  the h  e f f e c t was  being evalu-  s o u r c e of v a r i a t i o n , e s p e c i a l l y , s i n c e the m a t e r n a l  of egg weight had been e l i m i n a t e d by estimates  2 h, d Considering this i n -  2 e s t i m a t e s , which a l s o i n c r e a s e d s  d u r i n g the f o l l o w i n g weeks, i t i n d i c a t e d t h a t a new ated iri the dam  at  the i n c r e a s i n g body weight  f o r b o t h sexes.  always l a r g e r than  analyses at l e a s t  3 weeks o f age.  f o r body w e i g h t from 4 t o 8 weeks of age was  effect  2 The i n c r e a s e o f h^ i n a good agreement 2  w i t h those r e p o r t e d by Moyer e t a l . (1962), but not f o r the h ^ f o r the same c o r r e s p o n d i n g  traits.  There does not seem t o be  estimates any  - 136 -  v a l i d r e a s o n f o r a new age.  m a t e r n a l e f f e c t t o be i n i t i a t e d a t 4 weeks of  A p p a r e n t l y o t h e r f a c t o r s must be c o n s i d e r e d .  w i t h d i f f e r e n c e s between h  Sex l i n k a g e a s s o c i a t e d  2 2 and h., w h i c h s h o u l d 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 t o be the a n s w e r , s i n c e the s e x - l i n k a g e e f f e c t s h o u l d have e x i s t e d c o n s i s t e n t l y from h a t c h t o 3 weeks o f age, w h i c h a g a i n was not the c a s e . Thomas e t a l .  T h i s was c o n t r a r y t o t h e d i s c u s s i o n of  (1958).  The body w e i g h t h  2  2 e s t i m a t e s f o r each sex showed t h a t h ^ f o r b o t h  sexes were q u i t e s i m i l a r t h r o u g h o u t a l l w e e k l y e s t i m a t e s .  In contrast the  2 h g f o r the male progeny was  c o n s i s t e n t l y l o w e r f o r the e n t i r e p e r i o d of the  t e s t , an a p p r o x i m a t e d i f f e r e n c e of 0.10  i n f a v o u r of the f e m a l e p r o g e n y .  The  r e a s o n s f o r such a d L f f e r e n c e was not a p p a r e n t b u t d e f i n i t e l y i n d i c a t e d t h a t the a n a l y t i c a l p r o c e d u r e s i n s e p a r a t i n g the sexes was w o r t h w h i l e . 2 d i f f e r e n c e i n body w e i g h t h (1962) and Thomas e t a l .  T h i s sex  e s t i m a t e s has been n o t e d by M o y e r , e_t a l .  (1958). 2  The r e p l i c a t e d average of the h  e s t i m a t e s f o r w e e k l y growth r a t e s , 2 a l s o l i s t e d i n T a b l e 66, showed t h a t t h e h e s t i m a t e o f H - l w e e k l y growth 2 2 r a t e f o r b o t h sexes was v e r y low: h = 0.00 and 0.03: h , = 0.02 and 0.07 s d f o r males and f e m a l e s , r e s p e c t i v e l y .  These low e s t i m a t e s a r e n o t unexpected  s i n c e t h e H - l week growth r a t e had been shown t o be n e a r l y c o m p l e t e l y d e pendent upon the egg s i z e ( T a b l e 53).As a consequence t h i s p e r i o d o f g r o w t h was a r e c o v e r y 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  genetic d i f f e r e n c e s .  chick  As the d a t a i n d i c a t e s t h e s e g e n e t i c d i f f e r e n c e s appear  t o be w e l l masked d u r i n g the h a t c h i n g  phase.  2 The H-l values.  h  e s t i m a t e s f o r the 1-2  week growth r a t e s were h i g h e r t h a n the  R e c a l l i n g t h a t the r e c o v e r y phase was  a l s o demonstrated t o  e x i s t , a t 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  increased  2 h  estimates  f o l l o w s t h a t 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  o f extreme i n t e r e s t t o n o t e t h a t f o r the f i r s t 2 growth 2  p e r i o d s as w e l l as f o r a l l of the subsequent growth p e r i o d s the h for h  estimates  2 2 and h , w i t h i n b o t h sexes d i d not show any e v i d e n c e o f a m a t e r n a l s d  effect.  T h i s of c o u r s e was  i n d i r e c t c o n t r a s t t o the body w e i g h t d a t a where  the e v i d e n c e of a m a t e r n a l e f f e c t at h a t c h i n g , w h i c h d e c r e a s e d t o a minimum a t 3 weeks o f age,  and  subsequently increased t i l l  7 weeks o f age, was  quite  strong. 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 o f growth r a t e a n a l y s i s .  I f a s t r o n g m a t e r n a l 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 f l e c t e d i n the w e e k l y body w e i g h t s . c r e a s e d w i t h age  re-  R e c a l l i n g t h a t body w e i g h t v a r i a n c e i n -  (Table 25) a f a c t w h i c h has been demonstrated many t i m e s ,  i n the l i a t e r a t u r e , the a f o r e m e n t i o n e d e f f e c t would be e x p e c t e d t o i n c r e a s e i n p r o p o r t i o n t o the body w e i g h t v a r i a n c e . magnified  as the b i r d s get o l d e r .  The  I n o t h e r words i t s h o u l d  be  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 o f body w e i g h t s f o r 2 p e r i o d s of time f o r the same i n d i v i d u a l . T h i s r a t i o a p p a r e n t l y e l i m i n a t e d any  such e f f e c t t h a t was  consistent within  - 138 -  an i n d i v i d u a l .  W i t h the removal o f t h e s e e f f e c t s t h e h  2 estimate s  should  2 a p p r o x i m a t e v e r y c l o s e l y the h ^ v a l u e s w i t h i n each s e x . T h i s o f c o u r s e was 2 r e f l e c t e d i n t h e h e s t i m a t e s o b t a i n e d f o r w e e k l y growth r a t e s o f t h i s study. 2 The h  e s t i m a t e s f o r b o t h sexes f o r t h e 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 f e m a l e p r o g e n y .  The  2 2 male progeny may have shown a s l i g h t d e c l i n e i n b o t h h g and h ^ i n t h e l a t e r 2 growth p e r i o d s b u t no such change was apparent i n t h e f e m a l e p r o g e n y .  In  2 2 a d d i t i o n t h e s e may have been s l i g h t l y h i g h e r e s t i m a t e s f o r h g and h ^ i n t h e female p r o g e n y , b u t a g a i n t h i s was n o t c o n s i s t e n t . Such s e x d i f f e r e n c e s 2 were e v i d e n t when t h e h  e s t i m a t e s f o r t h e 1-3, 3-7 as w e l l as t h e 1-7 week  growth r a t e s were compared. 2 The male progeny f o r t h e 1-3 week growth r a t e had h = 0.27 and 2 2 h ^ = 0.22 w h i l e t h e s e h e s t i m a t e s were s i m i l a r t h e comparable f e m a l e progeny 2 2 had h .= 0.35 and h , = 0.24. W h i l e a d m i t t e d l y t h e sexes a t t h i s s t a g e may s d not be too d i f f e r e n t t h e same e s t i m a t e s f o r t h e 3-7 week growth r a t e showed male h  2 2 2 2 = 0 . 3 5 and h , = 0.32 w h i l e t h e female h = 0 . 6 9 and h , = 0.58. s d s d  C o n s i d e r i n g the s i z e o f the p o p u l a t i o n s t u d i e d i t would be r e a s o n a b l e t o 2 assume t h a t t r u e d i f f e r e n c e s i n t h e h  e s t i m a t e s do e x i s t a t l e a s t i n the  l a t t e r growth s t a g e s . 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 e s t i m a t e s were compared. The male progeny showed h g = 0 . 4 8 and h ^ = 0.43 2 2 and t h e female progeny showed h g = 0.74 and h^ = 0.63. I t s h o u l d be  - 139 -  p o i n t e d o u t t h a t t h e 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 v a l u e f o r t h e h e s t i m a t e s . F o r example i n t h e 2 male progeny t h e v a l u e s 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 . I n s p i t e of the notable increase i n the h estimates 2 2 e s p e c i a l l y c o n s i d e r the degree o f u n i f o r m i t y o f h^ and h ^ w i t h i n the male 2 progeny.  W h i l e the a f o r e m e n t i o n e d 3 growth p e r i o d s showed i n c r e a s i n g h  e s t i m a t e s an e x p l a n a t i o n o f t h i s e f f e c t was n o t e v i d e n t i n t h e d a t a , w i t h the e x c e p t i o n t h a t t h e 1-2 week growth r a t e has been n o t e d t o be w i t h i n t h e 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 t h e h e s t i m a t e was r e d u c e d . T h i s may be t h e u n i q u e e x p l a n a t i o n f o r t h e l o w e r 1-3 week growth rate h  2  estimates.  T h i s o f c o u r s e would mean t h a t 1-7 week growth r a t e h  2  e s t i m a t e w h i c h was much l a r g e r c o u l d have masked t h e 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 t h e p r e s e n t  data. 2  W h i l e t h e r e was no e v i d e n c e o f a s e x l i n k a g e e f f e c t found i n t h e h 2 d a t a o f the male progeny i t was i n t e r e s t i n g t o note t h a t f o r the h esti2 mates f o r t h i s 1-3, 3-7 and 1-7 week growth r a t e s o f 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 t h e a v e r a g e a d i f f e r e n c e o f 0.10 i n 2 favour of h^.  I n female p r o g r e n y where t h e female i s the h e t e r o g a m e t i c s e x  1/2 o f the v a r i a n c e o f the s e x - l i n k e d genes i s found i n t h e s i r e component of v a r i a n c e ( B e c k e r , 1 9 6 7 ) .  The dam component does n o t c o n t a i n any sex 2 2 l i n k a g e e f f e c t . T h e r e f o r e when t h e h exceeds t h a t o f t h e h . i n female s d progeny i t would be c o n s i d e r e d an i n d i c a t i o n of the I n f l u e n c e on t h e t r a i t 2 2 o f sex l i n k a g e . The h g and h ^ o f t h e male progeny r e f l e c t 1/4 and 1/2 o f  - 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 o f the m a l e s , however, t h i s p o s s i b l e e f f e c t cannot be o v e r l o o k e d i n t h a t the female progeny showed d e f i n i t e i n d i c a t i o n t h a t s u c h 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  e s t i m a t e d a t a showed  a major s o u r c e o f a d d i t i v e g e n e t i c v a r i a t i o n i s p r e s e n t i n p o u l t r y p o p u l a t i o n s , w h i c h h e r e t o f o r e , has n e v e r been d i r e c t l y e x p l o i t e d i n i m p r o v i n g the body w e i g h t of the young  chickens.  SUMMARY AND CONCLUSIONS  A t o t a l o f 7,472 progeny lorp  (BA), a New Hampshire  from 4 l i n e s o f c h i c k e n s , a B l a c k A u s t r a -  (NH) and 2 Leghorn  lines  (UBC and MH), t h e i r  c r o s s e s and t h e i r r e c i p r o c a l s were a s s e s s e d f o r t h e i r p r e - and p o s t h a t c h i n g body w e i g h t s ,  t h e i r p r e - 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 . i  The  i n t e r r e l a t i o n s h i p s o f these t r a i t s as they i n f l u e n c e d  and 7-week body weight were e v a l u a t e d . were j o i n t l y  sequent  1.  e s t i m a t e s (h ) o f t h e s e  f o l l o w i n g c o n c l u s i o n s were reached based  traits.  on the d a t a :  Sex d i f f e r e n c e s i n embryo body weights were found a t 8 t o 18 days o f embryo development.  T h i s d i f f e r e n c e c o u l d be a t t r i b u t a b l e t o a growth  r a t e d i f f e r e n c e between t h e sexes and i t was suggested embryonic 2.  relationships  c o n s i d e r e d as they i n f l u e n c e d t h e g e n e t i c v a r i a t i o n and sub2  estimates of the h e r i t a b i l i t y The  The e f f e c t o f t h e s e  growth  that this  d i f f e r e n c e o c c u r r e d much e a r l i e r i n  growth.  A maternal i n f l u e n c e , not r e l a t e d age,  f o r the 6-8 day embryo growth r a t e ,  on embryo weight  t o egg weight  a t l e a s t u n t i l 16 days  f o r b o t h sexes was found at 6 t o 18 days o f incu-  bation. 3.  A l l s i r e x dam i n t e r a c t i o n s  t h a t were c o n s i s t e n t l y s i g n i f i c a n t  a n a l y s e s of v a r i a n c e o f body weight  from h a t c h t o 7 weeks o f age were  not i n e v i d e n c e when the d a t a was a n a l y s e d based u s i n g the power f u n c t i o n  (Y a t -) . - =141 b  for a l l  on growth r a t e (b)  T h i s suggests  t h a t growth  rate  - 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 t h a t bod}' w e i g h t shows an i n t e r a c t i o n t h a t i s n o t g e n e t i c a l l y d e t e r m i n e d but r a t h e r an a r t i f a c t o f the n o n - l i n e a r i t y o f body w e i g h t p e r se. 4.  The v a l u e o f the power f u n c t i o n i n t r a n s f o r m i n g  the d a t a was  again  demonstrated i n t h a t t h e 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 w e i g h t a n a l y s e s were c o n s i s t e n t l y s i g n i f i c a n t t h r o u g h o u t the growth r a t e a n a l y s e s 5.  f o r each s e x .  The e n v i r o n m e n t a l i n f l u e n c e o f egg w e i g h t , r e p o r t e d i n t h e l i t e r a t u r e , was s t r o n g l y demonstrated i n t h a t on t h e average 76 p e r c e n t o f t h e v a r i a t i o n i n h a t c h i n g w e i g h t c o u l d 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 o f egg w e i g h t .  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 ( t h e r e c o v e r y phase) was d e m o n s t r a t e d i n the H - l week g r o w t h r a t e as i t showed the s t r o n g e s t a s s o c i a t i o n w i t h egg  7.  weight.  The a d v e r s e e n v i r o n m e n t a l e f f e c t o f 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 n t h a t i t took 2 weeks o f growth a f t e r h a t c h i n g  f o r t h e c h i c k e n body  w e i g h t s to a t t a i n the same l e v e l o f a s s o c i a t i o n w i t h 7-week body w e i g h t t h a t was p r e v i o u s l y shown i n t h e body w e i g h t s o f t h e 18 day embryo. 8.  The r e l a t i v e independence of t h e 2 t r a i t s  (body w e i g h t and growth r a t e )  was e s t a b l i s h e d , however, when an a d v e r s e environment g r o w t h , t h i s independence was m o d i f i e d surement .  influenced  f o r t h a t weeks growth r a t e mea-  - 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 t h a t 1 week body w e i g h t and any subsequent growth p e r i o d s a c c o u n t e d f o r more v a r i a t i o n i n 1-week body w e i g h t than d i d t h e use o f h a t c h i n g w e i g h t , and i t s subsequent growth p e r i o d s , because h a t c h i n g w e i g h t was p r i m a r i l y r e l a t e d t o . e g g s i z e and the growth f o r H - l week o f age was b a s i c a l l y a r e c o v e r y 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 o f r e p l i c a t i o n was e v i d e n t t h r o u g h o u t t h e s t u d y , and a s i d e from some unique p e r i o d s o f growth was b a s i c a l l y  attributable  to egg s i z e d i f f e r e n c e s between t h e two r e p l i c a t i o n s , ( 5 5 . 3 and 60.3 grams). T h i s was due t o a 7-week d i f f e r e n c e i n t h e age o f t h e dams. 1 1 . The s t r o n g m a t e r n a l e f f e c t n o t e d i n t h e embryo body w e i g h t a n a l y s e s was 2 r e a f f i r m e d w i t h t h e h e s t i m a t e f o r each sex and r e p l i c a t i o n i n t h a t 2 2 h g was v e r y l o w and h ^ r e l a t i v e l y l a r g e . 12. The m a t e r n a l e f f e c t o f egg w e i g h t on t h e body w e i g h t o f t h e h a t c h e d 2 c h i c k s was d e m o n s t r a b l e i n t h e h  e s t i m a t e s o n l y u n t i l 2 weeks o f a g e ,  and i t was n i l a t 3 weeks of a g e . 2 13. A new m a t e r n a l e f f e c t on body w e i g h t n o t e d i n t h e h e s t i m a t e s c o u l d be measured s t a r t i n g a t 4 weeks o f age, the r e a s o n f o r t h i s e f f e c t c o u l d n o t be a t t r i b u t a b l e t o any know s o u r c e o f 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 a d v e r s e e f f e c t of egg w e i g h t on t h e H - l and 1-2 week growth r a t e .  T h i s was  c o n s i d e r e d t o be analogous t o t h e a f o r e m e n t i o n e d m a t e r n a l i n f l u e n c e on body w e i g h t .  - 144 -  15.  The h  and h , o f growth r a t e e s t i m a t e s f o r b o t h sexes d i d n o t demons  d  s t r a t e any change s t a r t i n g a t 4 weeks o f age o r t h e r e a f t e r t h a t  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 t h e h e s t i m a t e o f 4 week body w e i g h t , t h e r e f o r e , i t was s u g g e s t e d t h a t due 2 t o t h e method o f c a l c u l a t i o n o f w e e k l y growth r a t e t h e h  estimate of  t h a t t r a i t would be e x p e c t e d t o be r e l a t i v e l y c o n s t a n t s t a r t i n g a t 2 weeks o f a g e . 2 16.  The h  e s t i m a t e s o b t a i n e d f o r a l l w e e k l y g r o w t h r a t e s as w e l l as t h e  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 s o u r c e o f 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 p o p u l a t i o n s f o r e n o t u t i l i z e d d i r e c t l y i n body w e i g h t s e l e c t i o n p r o g r a m s .  hereto-  BIBLIOGRAPHY  B e c k e r , W.A., 1967. Manual of p r o c e d u r e s i n q u a n t i t a t i v e g e n e t i c s . Washington S t a t e U n i v e r s i t y P r e s s , P u l l m a n , W a s h i n g t o n . B l u n n , C.T. and P.W. G r e g o r y , 1935. i n h e r i t a n c e i n the c h i c k e n .  The e m b r y o l o g i c a l b a s i s o f s i z e J . E x p . Zod. 70: 347-414.  B r a y , D.F. and E.L. I t o n , 1962. 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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 o f egg w e i g h t on subsequent b r o i l e r p e r f o r m a n c e . P o u l t r y S c i . 43:534-539. Upp, C.W., 1928. Egg w e i g h t , day o l d c h i c k w e i g h t and r a t e o f growth i n S i 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. W a t e r s , N.F. and J . H . B y w a t e r s , 1943. A s t u d y o f body w e i g h t s i n n i n e d i f f e r e n t s t r a i n s o f White L e g h o r n s . 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 o f egg w e i g h t on t h e p r e - h a t c h i n g and p o s t - h a t c h i n g growth r a t e i n t h e f o w l . I . Egg w e i g h t - e m b r y o n i c 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 o f egg w e i g h t on the p r e - h a t c h i n g and p o s t - h a t c h i n g g r o w t h r a t e i n t h e f o w l . II. Egg w e i g h t - c h i c k w e i g h t r a t i o s . P o u l t r y S c i . 29: 595-604.  - 151 -  APPENDIX  L I S T OF APPENDIX TABLES  Appendix T a b l e 1  2  3  4  Page Number o f Embryos o f Males and Females i n Each R e p l i c a t i o n and Genotype f o r E v e r y Day Weighed  153  Mean Embryo Growth. R a t e s W i t h i n Each Sex and Genotype f o r V a r y i n g Growth Periods Across R e p l i c a t i o n s  155  Mean Embryo Growth R a t e s by S i r e and Dam L i n e o f M a l e s and Females f o r V a r y i n g Growth P e r i o d s A c r o s s R e p l i c a tions  157  Number of P o s t - h a t c h 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  Sire BA D a line  m  R  MH  l  Day  M  6 8 10 12 14 16 18  17 9 8 10 8 14  6 8 10 12 14 16 18  11 8 10 7 2 9  2 F  line  M  1  F  19  M  17 6 14 13 10 9 8  5 9 7 14 9 8  8 5 8 6 11 8  13 9 13 9 11 12  19  NH 2  F  14 14 14 5 10 12  8 17 7 15 8 9  9 7 7 8 6 4  20  1 F  M  16  23 15 9 12 7 9 5  M  7 5 9 14 14 11  11 10 12 6 13 10  8 10 8 9 10 10  15 14 9 10 8 7  2 F  M  11 14 9 11 12 13  8 10 11 11 8 10  10 5 8 7 8 5  13 7 10 13 9 6  12 17 7 9 9 6  5 10 7 10 9 9  13 8 15 7 5 5  20  Total  1 F  2  M  17  21 6 12 8 9 6 7  15  15  UBC  F  M  12 10 9 13 8 9  7 12 6 12 10 10  10 14 12 11 8 10  7 12 10 9 9 12  8 14 9 13 11 9  8 6 6 9 8 8  21 18 9 9 13 9  22  20  F  M  2 F  M  82  21  19 7 4 10 10 11 8  1  71  14 7 13 11 8 11  54 47 40 39 38 48  5 8 10 17 9 14  76 40 29 34 31 37 29 34 33 24 • 38 28 35  21  F  33 38 42 46 41 37  Continued  36 50 35 42 42 33  42 32 43 37 34 31  76 62 49 46 35 37 33  28 47 34 55 35 43  APPENDIX TABLE  1.  (Continued)  Sire BA Dam line  R Day  MH  1 M  2 F  20  6 8 10 12 14 16 18  9 12 9 8 14 11  6 8 10 12 14 16 18  10 12 11 9 7 7  12 16 11 15 7 7  9 6 8 8 8 9  16 14 7 16 10 13  M  13 9 11 9 14 15  10 10 11 13 12 14  10 6 17 11 14 5  8 12 14 8 16 9  213  263  F  M  15 11 12 7 7 9  12 13 12 15 9 10  13 11 6 11 5 15  9 11 6 8 14 11  255  247  T o t a l n o . o f 6 day embryos  F  M  237  F  M  10 14 12 9 10 5  13 8 11 12 11 10  14 10 15 10 10 11  20 8 9 12 6 7 9 11 10 11 9 16 7  12 14 10 11 10 11  237  M  F  224  15 9 15 10 10 14  11 9 10 10 9 11  8 11 8 13 15 8  M  F  217  12 9 11 17 10 12  8 6 7 10 4 9  12 14 8 6 11 14  F  206  44 45 47 40 46 44  7 2 10 13 9 8  34 47 40 40 49 40  212  48 55 52 57 39 42  39 29 30 40 26 40  49 53 31 41 45 49  35 34 32 32 42 36  90  320* 978  F  81 47 39 45 40 37 35  75  81* 279  M 87  6 8 6 5 7 4  21  81* 262  M  2  18 6 11 8 11 13 9  16  78* 264  1  24 10 7 6 9 9 9  19  83*  Total  2  22  6 10 9 9 12 8  230  1 F  12 17 18 10 13 13  73* 255  2  22  25  79*  UBC  1  17  20  86*  77*  2  21  25  19  232  F 24  13 9 14 10 6 7  NH  1  M  line  880  42 27 52 44 42 35 318*  1061  914  - 155 APPENDIX TABLE 2. MEAN EMBRYO GROWTH RATES WITHIN SEX AND GENOTYPE FOR VARYING GROWTH PERIODS ACROSS R E P L I C A T I O N S  Sire BA Dam line  BA  MH  NH  UBC  EACH  line  MH  NH  UBC  Day  Male  Female  Male  Female  Male  Female  Male  Female  6-10 6-12 6-14 6-16 6-18 8-12 8-14 8-16  3.80 3.94 3.98 3.92 3.74 3.72 3.84 3.79  3.68 3.86 3.98 3.92 3.70 3.61 3.86 3.80  3.78 3.92 4.02 3.87 3.72 3.72 3.92 3.76  3.84 3.84 3.99 3.84 3.70 3.77 3.99 3.82  3.66 3.97 3.92 3.86 3.72 4.00 3.92 3.84  3.61 3.88 3.86 3.78 3.70 3.90 3.88 3.77  3.68 3.74 3.96 3.84 3.72 3.62 3.96 3.82  3.60 3.74 3.90 3.82 3.72 3.70 3.92 3.82  6-10 6-12 6-14 6-16 6-18 8-12 8-14 8-16  3.92 4.08 4.10 4.00 3.89 3.82 3.95 3.86  3.87 4.00 4.16 3.99 3.84 3.64 3.97 3.80  3.98 3.99 4.16 4.05 3.82 3.72 4.02 3.93  3.98 4.01 4.06 4.02 3.80 3.88 3.98 3.95  3.92 4.05 4.09 4.00 3.91 3.86 3.98 3.89  3.96 4.02 4.12 3.97 3.84 4.02 4.16 3.96  3.96 4.05 4.10 4.01 3.86 3.78 3.94 3.87  3.90 3.94 4.14 4.02 3.85 3.62 3.98 3.88  6-10 6-12 6-14 6-16 6-18 8-12 8-14 8-16  3.92 3.98 4.06 4.00 3.84 3.70 3.89 3.86  3.83 3.83 4.04 4.01 3.80 3.59 3.96 3.94  3.92 4.04 4.06 3.99 3.85 3.82 3.93 3.86  3.74 3.94 4.11 4.03 3.88 3.82 4.09 4.00  3.86 3.94 4.10 3.98 3.88 3.74 4.01 3.88  3.88 3.94 4.10 3.98 3.84 3.84 4.08 3.94  3.93 3.93 4.08 3.96 3.77 3.68 3.98 3.84  3.82 3.96 4.04 3.96 3.80 3.82 3.96 3.88  6-10 6-12 6-14 6-16 6-18 8-12 8-14 8-16  3.80 3.91 4.04 3.97 3.82 3.62 3.90 3.84  3.77 3.84 3.98 3.90 3.82 3.62 3.88 3.80  4.06 3.97 4.06 3.92 3.81 3.58 3.84 3.72  3.96 3.90 4.04 3.99 3.82 3.58 3.87 3.86  4.06 4.04 4.16 4.02 3.86 3.76 4.02 3.87  3.98 4.00 4.12 4.00 3.88 '3.68 3.95 3.84  3.92 4.00 4.04 3.94 3.80 3.80 3.92 3.82  3.89 3.88 4.04 4.00 3.85 3.76 4.02 3.96  Continued  - 156 APPENDIX T A B L E 2.  (Continued)  Sire BA Dam line  line  MH Male  NH  Day  Male  Female  Female  BA  8-18 10-14 10-16 10-18 12-16 12-18 14-18  3.62 4.16 3.98 3.72 3.87 3.55 3.27  3.58 4.28 4.08 3.71 4.01 3.54 3.14  3.60 4.26 3.93 3.70 3.80 3.54 3.13  3.64 4.13 3.84 . 3.64 3.86 3.56 3.14  MH  8-18 10-14 10-16 10-18 12-16 12-18 14-18  3.76 4.29 4.04 3.88 3.88 3.72 3.47  3.66 4.45 4.07 3.82 3.96 3.68 3.20  3.68 4.34 4.10 3.74 4.14 3.66 3.16  NH  8-18 10-14 10-16 10-18 12-16 12-18 14-18  3.69 4.19 4.05 3.79 4.02. 3.69 3.39  3.70 4.25 4.12 3.78 4.28 3.78 3.32  UBC  8-18 10-14 10-16 10-18 12-16 12-18 14-18  3.69 4.29 4.09 3.84 4.06 3.73 3.38  3.74 4.18 3.98 3.86 3.98 3.80 3.52  Male  UBC Female  Male  Female  3.68 4.19 3.99 3.74 3.70 3.47 3.30  3.68 4.12 3.90 3.74 3.65 3.52 3.36  3.66 4.24 3.96 3.73 4.01 3.69 3.22  3.70 4.20 3.96 3.78 3.92 3.70 3.36  3.70 4.12 4.03 3.70 4.02 3.58 3.27  3.80 4.26 4.06 3.90 3.92 3.76 3.54  3.81 4.28 3.98 3.78 3.90 3.66 3.29  3.72 4.22 4.05 3.80 3.97 3.67 3.39  3.70 4.36 4.10 3.82 4.14 3. 76 3.28  3.72 4.22 4.04 3.82 3.90 3.66 3.41  3.82 4.48 4.22 3.94 4.17 3.81 3.40  3.78 4.34 4.06 3.88 4.02 3.80 3.43  3.78 4.32 4.04 3.83 4.04 3.75 3.34  3.64 4.25 3.98 3.70 4.02 3.61 3.14  3.70 4.25 4.04 3. 78 3.94 3.63 3.32  3.62 4.06 3.84 3.68 3.86 3.64 3.30  3.68 4.12 4.02 3.76 4.13 3.75 3.40  3.72 4.26 3.98 3.76 3.98 3.68 3.25  3.73 4.26 4.00 3.83 4.00 3.76 3.40  3.68 4.16 3.96 3.74 3.86 3.60 3.33  3.80 4.20 4.07 3.84 4.16 3.82 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  Sire line  Dam l i n e  Period of growth (day)  M  6-10 6-12 6-14 6-16 6-18  3.86 3.98 4.04 3.97 3.82  3.79 3.88 4.04 3.95 3.79  3.93 3.98 4.07 3.96 3.80  3.88 3.92 4.05 3.97 3.80  3.88 4.00 4.07 3.96 3.84  3.86 3.96 4.05 3.93 3.82  3.88 3.93 4.05 3.94 3. 79  3.80 3.88 4.03 3.95 3.80  3.73 3.89 3.97 3.87 3.73  3.68 3.83 3.94 3.84 3.70  3.95 4.04 4.11 4.02 3.87  3.93 3.99 4.12 4.00 3.83  3.91 3.98 4.08 3.98 3.83  3.82 3.92 4.07 3.99 3.83  3.96 3.98 4.08 3.96 3.82  3.90 3.90 4.05 3.97 3.84  8-12 8-14 8-16 8-18  3. 72 3.89 3.84 3.69  3.62 3.92 3184 3.67  3.71 3.93 3.82 3.66  3.76 3.98 3.90 3. 71  3.84 3.98 3.87 3.74  3. 86 4.02 3. 88 3. 75  3.72 3.94 3.84 3.68  3.72 3.97 3.88 3.72  3.76 3.91 3.80 3.64  3.74 3.91 3.80 3.65  3.80 3.97 3.89 3. 74  3.79 4.02 3.90 3.72  3.74 3.95 3.86 3.71  3. 76 4. 02 3. 94 3. 75  3.69 3.92 3.82 3.68  3.66 3.93 3.86 3.74  10-14 10-16 10-18  4.23 4.04 3.81  4.29 4.06 3.79  4.22 3.98 3.74  4.21 4.03 3.76  4.26 4.02 3.82  4.24 3.98 3.80  4.22 3.99 3.74  4.25 4.05 3.81  4.21 3.97 3.72  4.18 3.95 3. 72  4.28 4.06 3.83  4.30 4.05 3. 78  4.25 4.03 3.80  4.02 4.11 3.84  4.19 3.96 3.75  4. 19 4. 02 3. 82  12-16 12-18  3.96 3.67  4.06 3.70  3.92 3.62  4.04 3.68  3.91 3.68  3.90 3.68  3.96 3.64  4.04 3.72  3.84 3.56  3.86 3.58  3.98 3.70  4.01 3.67  3.99 3.69  4.11 3. 74  3.94 3.66  4. 07 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  BA F  MH M  NH  F  M  UBC  F  M  BA  F  M  MH  F  M  NH  F  M  UBC  F  M  F  APPENDIX TABLE 4.  NUMBER OF POST-HATCH PROGENCIES FOR EACH SEX GENOTYPE AND " REPLICATION  Sire BA Dam line BA  MH  NH  UBC  Total  Replication  line  MH  NH  UBC  Total  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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