UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Estimation of genetic and environmental parameters of lifetime production traits and longevity in Holstein-Friesian… Hoque, Mozzamel 1980

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1980_A1 H66.pdf [ 7.47MB ]
Metadata
JSON: 831-1.0095413.json
JSON-LD: 831-1.0095413-ld.json
RDF/XML (Pretty): 831-1.0095413-rdf.xml
RDF/JSON: 831-1.0095413-rdf.json
Turtle: 831-1.0095413-turtle.txt
N-Triples: 831-1.0095413-rdf-ntriples.txt
Original Record: 831-1.0095413-source.json
Full Text
831-1.0095413-fulltext.txt
Citation
831-1.0095413.ris

Full Text

ESTIMATION OF GENETIC AND ENVIRONMENTAL PARAMETERS OF L I F E T I M E PRODUCTION TRAITS AND LONGEVITY I N H O L S T E I N - F R I E S I A N COWS  By  MOZZAMEL (HOQUE B.Sc,  Dacca U n i v e r s i t y ,  B a n g l a d e s h , 1961  M.Sc,  Texas A & M U n i v e r s i t y ,  U.S.A., 1965  A THESIS SUBMITTED I N PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY  in THE FACULTY OF GRADUATE STUDIES Department o f Animal S c i e n c e  We a c c e p t t h i s t h e s i s a s c o n f o r m i n g to the r e q u i r e d standard  THE UNIVERSITY OF B R I T I S H COLUMBIA M a r c h 1980 (2)  M o z z a m e l Hoque, 198 0  In p r e s e n t i n g t h i s  thesis  in p a r t i a l  fulfilment  o f the requirements  for  an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y I further  available  f o r reference and study.  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  thesis  f o r s c h o l a r l y purposes may be granted by the Head o f my Department or by h i s r e p r e s e n t a t i v e s . of  this  It  thesis f o r financial  i s understood that copying or p u b l i c a t i o n g a i n s h a l l not be allowed without my  written permission.  Department o f  Animal Science  The U n i v e r s i t y o f B r i t i s h Columbia  2075 Wesbrook Place Vancouver, Canada V6T 1W5  Date  A p r i l 15, 1980  ABSTRACT  This and  s t u d y was u n d e r t a k e n  environmental  longevity t r a i t s Performance freshened used, of  aspects of l i f e t i m e of dairy c a t t l e .  t h u s a l l o w i n g cows t i m e  t o complete  by t h e end o f 1974.  lactation  2090 h e r d s The  Canadian  cows w h i c h  8 o r more  traits  i n c l u d e d were f i r s t  first  lactation  last  and  fat yields;  last  length; t o t a l  and  fat yields;  m i l k and f a t y i e l d s  by  lactation  age a t c u l l i n g ;  lactation  which might  interaction.  lifetime  milk  and number  have a s i g n i f i c a n t  f o r the f i r s t  first  calving  and c a l v i n g  cows.  lactation  interval  A l leffects  Traits  influence  season  on  and y e a r  The c o v a r i a b l e s u s e d were age a t  calving  technique.  305-day m i l k  length of productive l i f e ;  first  lactation  year  p e r day o f p r o d u c t i v e  u n d e r s t u d y were t h o s e o f h e r d , y e a r ,  season  herd  lactation  completed.  Effects traits  cows  a c r o s s Canada.  performance  lactations  years included  lactation  d e v i a t i o n m i l k and f a t y i e l d s ;  of  first  1966 were  These d a t a  and 28581 m u l t i p l e  305-day m i l k a n d f a t y i e l d s ;  life;  Record of  September, 1957 t h r o u g h F e b r u a r y ,  productive l i f e  from  p r o d u c t i o n and  (ROP) d a t a o f 51,599 H o l s t e i n  from  23018 f i r s t  to evaluate the g e n e t i c  cows, and age a t  f o r the multiple  were e v a l u a t e d by l e a s t  under study f o r f i r s t  were a d j u s t e d f o r age a t f i r s t  calving,  lactation  squares  cows  and t h o s e f o r  - i i i -  multiple lactation  cows w e r e a d j u s t e d  f o r b o t h age a t  c a l v i n g and c a l v i n g i n t e r v a l ; t h e r e s u l t i n g a d j u s t e d were a n a l y z e d of genetic  first data  on w i t h i n h e r d - y e a r - s e a s o n b a s i s f o r e s t i m a t i o n  parameters.  H e r i t a b i l i t y o f e a c h t r a i t and p h e n o t y p i c  and  genetic  c o r r e l a t i o n s among t h e t r a i t s w e r e d e r i v e d f r o m p a t e r n a l h a l f - s i b a n a l y s i s u s i n g d a u g h t e r s o f 138 s i r e s o f f i v e groups according  t o s i r e ' s year  sets of h e r i t a b i l i t y estimates (i)  first  lactation  first  deviation f a t yield  .22 and .20, f i r s t  life and  estimates f o r ( i i )multiple  305-day m i l k  length  fat yield  lactation  305-day f a t y i e l d  .22 a n d  lactation  .24 a n d .25, l a s t l a c t a t i o n  .14 a n d .11, l a s t l a c t a t i o n  lifetime  lactation  and  separate  305-day f a t .25 and .25, f i r s t  deviation milk  last lactation  Two  were o b t a i n e d ;  combined f i r s t and m u l t i p l e l a c t a t i o n  l a c t a t i o n cows w e r e :  year  of b i r t h .  herd-  herd-year 305-day  .16 and  .06 a n d .07, l i f e t i m e m i l k  .12 and .12, m i l k p e r d a y o f  .20,  milk  .14,  .11 and . 1 1 , productive  .21 a n d .21, f a t y i e l d p e r d a y o f p r o d u c t i v e  life  .28, c u l l i n g age .10 a n d .09, l e n g t h o f p r o d u c t i v e  .25 life  .10 a n d .09, a n d number o f l a c t a t i o n s .09 and .08, r e s p e c t i v e l y . The a v e r a g e a n n u a l p h e n o t y p i c were  and g e n e t i c  72 k g a n d 31.2 k g , r e s p e c t i v e l y f o r f i r s t  m i l k , 2.89 k g a n d .91 k g , r e s p e c t i v e l y f o r f i r s t fat.  trends  lactation lactation  -  Genetic fat  from  combined  from  of f i r s t  l a c t a t i o n m i l k and  l i f e t i m e p r o d u c t i o n and l o n g e v i t y t r a i t s  .34 t o .93 and .41 t o .47, r e s p e c t i v e l y f o r  first  correlations  for  correlations  y i e l d s with  ranged  iv -  and m u l t i p l e l a c t a t i o n  cows.  among m e a s u r e s o f l i f e t i m e  production  .46 t o .96 and among l o n g e v i t y t r a i t s t h e same s e t o f d a t a .  Separate  with higher standard  f r o m combined  e r r o r than  set of data.  were  ranged  .99 o r above  estimates of genetic  c o r r e l a t i o n s b a s e d on m u l t i p l e l a c t a t i o n lower  The g e n e t i c  cows o n l y were a l l  the estimates  obtained  The g e n e t i c c o r r e l a t i o n s  that  were c o n s i d e r e d a s h a v i n g  h i g h p r e d i c t i v e v a l u e were:  l a c t a t i o n milk correlated  h i g h l y and p o s i t i v e l y w i t h  l a c t a t i o n m i l k a n d m i l k p e r day o f p r o d u c t i v e l i f e ; lactation  fat yield  h i g h l y and p o s i t i v e l y  lactation  f a t y i e l d and f a t y i e l d  S i r e s were r a n k e d breeding values The  correlations  yields  o f EBV's f o r f i r s t  first  b a s e d on t h e i r  lactation  yields  l o n g e v i t y were p o s i t i v e  correlations  l i f e t i m e milk y i e l d life  last  life.  expected  with (.31 t o  l a c t a t i o n m i l k and f a t y i e l d s  p e r day o f p r o d u c t i v e l i f e ,  productive  correlated with  t o be good p r e d i c t o r s o f EBV's f o r m i l k and f a t  Genetic with  first  (EBV) f o r p r o d u c t i o n and l o n g e v i t y t r a i t s .  The EBV's f o r f i r s t  were f o u n d  last  p e r day o f p r o d u c t i v e  differently  l i f e t i m e p r o d u c t i o n and w i t h .89).  first  (.93)  respectively.  of f i r s t  lactation milk  yield  (.56)  and m i l k y i e l d  p e r day o f  indicate  that continued  selection  l a c t a t i o n m i l k p r o d u c t i o n i s an e f f e c t i v e means o f  on  m a x i m i z i n g l i f e t i m e m i l k a n d m i l k p e r day o f life.  productive  S i g n i f i c a n t p o s i t i v e genetic a s s o c i a t i o n of  first  l a c t a t i o n p r o d u c t i o n w i t h l i f e t i m e p e r f o r m a n c e and l o n g e v i t y suggest t h a t high producing fat  h e i f e r s p r o d u c e more m i l k  d u r i n g t h e i r l i f e t i m e and r e m a i n i n h e r d s l o n g e r  lower  producing  heifers.  These r e l a t i o n s  lactation level of production  b u l l s which w i l l later l i f e  should  s i r e daughters which w i l l  and w i l l  remain i n the herd  than  further indicate  t h a t t h e method o f A . I . s i r e e v a l u a t i o n u s i n g first  and  daughters'  r e s u l t i n proven produce w e l l i n  longer.  - v i-  TABLE OF CONTENTS  Page  ABSTRACT  i  TABLE '.OF CONTENTS  i v i  L I S T OF TABLES  viii  L I S T OF FIGURES  x i  L I S T OF APPENDICES  x i i  ACKNOWLEDGEMENTS  xiii  INTRODUCTION  1  LITERATURE REVIEW  6  L o n g e v i t y and D i s p o s a l  Reasons  6  Sources o f V a r i a t i o n i n L i f e t i m e P r o d u c t i o n and L o n g e v i t y H e r i t a b i l i t y Estimates of F i r s t M i l k and F a t Y i e l d s R e l a t i o n s h i p Between F i r s t Lactations  11 Lactation 19  and L a t e r '  I n h e r i t a n c e o f L o n g e v i t y and Lifetime Production  19 .  21  Relationships of F i r s t Lactation Yields W i t h L i f e t i m e Performance and L o n g e v i t y  22  R e l a t i o n s h i p o f S i r e B r e e d i n g V a l u e and S u r v i v a l o f Tested Daughters MATERIALS AND METHODS  24 26  S o u r c e and D e s c r i p t i o n o f D a t a  26  Performance T r a i t s  28  S t a t i s t i c a l Technique  30  Analyses f o r environmental parameters  30  Adjustment o f data  38  -  V l l -  Analyses f o r Estimation  of Genetic  Parameters . . .  .40  Estimation  of h e r i t a b i l i t y  46  Estimation  of genetic  trend  48  Estimation  of genetic  correlation  49  E s t i m a t i o n o f p h e n o t y p i c and e n v i r o n m e n t a l correlations  51  Estimation  52  of breeding value  RESULTS AND DISCUSSION".  54  Means and V a r i a t i o n s o f T r a i t s Environmental Parameters A f f e c t i n g P r o d u c t i o n and L o n g e v i t y .  54 Lifetime 56  R e l a t i o n s h i p s o f Age a t F i r s t C a l v i n g P r o d u c t i o n and L o n g e v i t y Relationships Production  of Calving  Interval  with 68  with  and L o n g e v i t y  72  Adjustment o f Data Estimations  of Genetic  74 Parameters  Genetic  trends  Genetic  components o f v a r i a n c e  75 79 and  covariance  85  H e r i t a b i l i t y estimates  87  correlations  95  1" •• P h e n b ' t y p i c ' ' c o r i ? e i a t i o n s ;  99  -T G e n e t i c " c o r r e l a t i o n s Relationships of Expected Breeding Values f o r F i r s t Lactation Yields with Lifetime Production  102  and  107  :  Longevity  CONCLUSIONS  1  1  5  BIBLIOGRAPHY  1  2  4  - viii  -  L I S T OF TABLES Table 1 2 3 4  5  6  7  8  9  10  Page C o m p a r a t i v e c u l l i n g r a t e and l e n g t h of h e r d l i f e i n d i f f e r e n t c o u n t r i e s  7  Summary o f r e c e n t r e s e a r c h on d a i r y cow d i s p o s a l s  8  D i s p o s a l r e a s o n s by l a c t a t i o n number when d i s p o s e d  10  Means, s t a n d a r d d e v i a t i o n s (SD), and c o e f f i c i e n t s o f v a r i a t i o n (CV) of t r a i t s , u s i n g d a t a o f combined G r o u p s 1 & 2, c a l c u l a t e d w i t h i n herd-year-season of f i r s t c a l v i n g  55  Summary o f t h e a n a l y s i s o f variance-covariance f o r e n v i r o n m e n t a l e f f e c t s : f o r Group 1  58  Summary o f t h e a n a l y s i s o f v a r i a n c e covariance f o r environmental e f f e c t s : f o r Group 2  59  A v e r a g e y e a r l y and s e a s o n a l t r e n d s i n p r o d u c t i o n and l o n g e v i t y t r a i t s b a s e d on l e a s t s q u a r e s c o n s t a n t s o b t a i n e d f r o m a n a l y s e s on m o d e l s 1 and 2  62  W i t h i n h e r d c o r r e l a t i o n s o f age a t f i r s t c a l v i n g (age), average c a l v i n g i n t e r v a l (C.I.Av.) and last calving interval (C.I.L.) w i t h p r o d u c t i o n and l o n g e v i t y  70  Within herd r e g r e s s i o n s (adjusted) f o r y e a r and season e f f e c t s ) o f age a t f i r s t c a l v i n g ( A g e ) , average c a l v i n g i n t e r v a l (C.I.Av.), and l a s t c a l v i n g i n t e r v a l (C.I.L.) on p r o d u c t i o n a n d l o n g e v i t y t r a i t s  71  Number o f s i r e s a n d d a u g h t e r s i n each g e n e t i c group: f o r Groups 1 and 2 c o m b i n e d  76  - ix-  11  12 13  14  15  16 17  18  19  20  21  22  Summary o f t h e a n a l y s i s o f v a r i a n c e f o r a d j u s t e d d a t a : f o r Groups 1 and 2 combined  77  Summary o f t h e a n a l y s i s o f v a r i a n c e f o r a d j u s t e d d a t a : f o r Group 2  78  Genetic group l e a s t squares c o n s t a n t s and g e n e t i c p r o g r e s s p e r y e a r f o r p r o d u c t i o n and l o n g e v i t y t r a i t s : f o r Groups 1 and 2 combined The e x p e c t e d c o m p o n e n t s o f v a r i a n c e and c o v a r i a n c e f o r t w o t r a i t s f i t t i n g t h e same m o d e l . H e r i t a b i l i t y estimates f o r f i r s t lactation yields, lifetime • p r o d u c t i o n , and l o n g e v i t y t r a i t s -  80  86  • • • • • .88  H e r i t a b i l i t y estimates of f i r s t three lactations i n Holstein  90  H e r i t a b i l i t y estimates of l i f e t i m e p r o d u c t i o n and longevity i n Holstein  92  P h e n o t y p i c c o r r e l a t i o n s (above d i a g o n a l ) and g e n e t i c c o r r e l a t i o n s (below d i a g o n a l ) : f o r c o m b i n e d Groups 1 and 2  96  P h e n o t y p i c c o r r e l a t i o n s (above d i a g o n a l ) and g e n e t i c c o r r e l a t i o n s (below d i a g o n a l ) : f o r Group 2  97  Summary o f p h e n o t y p i c (above) and g e n e t i c (below) c o r r e l a t i o n s of f i r s t l a c t a t i o n y i e l d s w i t h l i f e t i m e p r o d u c t i o n and longevity t r a i t s  101  P h e n o t y p i c (above d i a g o n a l ) and g e n e t i c (below d i a g o n a l ) c o r r e l a t i o n s among l i f e t i m e p r o d u c t i o n and l o n g e v i t y t r a i t s : f o r Groups 1 & 2 combined  103  D i f f e r e n c e s i n average expected b r e e d i n g v a l u e s (EBV) f o r v a r i o u s groupings of b u l l s  108  Product-moment c o r r e l a t i o n s between breeding values of s i r e s f o r l i f e t i m e p r o d u c t i o n t r a i t s and longevity Product-moment c o r r e l a t i o n s between e x p e c t e d b r e e d i n g " v a l u e s (EBV) f o r first lactation yields, lifetime p r o d u c t i o n and l o n g e v i t y Regressions of expected breeding v a l u e (EBV) m i l k a n d / o r e x p e c t e d b r e e d i n g v a l u e f a t on e x p e c t e d breeding values f o r l i f e t i m e p r o d u c t i o n and l o n g e v i t y  - x i -  L I S T OF FIGURES  Figure  1  Page  Yearly trends  of f i r s t  lactation  milk yield 2 3  4  5  6  7  Yearly trends fat yield  63 of f i r s t  lactation 64  Yearly trends of l i f e t i m e milk and l i f e t i m e f a t y i e l d s : f o r Group 2  65  Yearly trends of length of p r o d u c t i v e l i f e a n d number o f l a c t a t i o n s completed: f o r Group 2  66  Genetic group trends of f i r s t l a c t a t i o n m i l k and f a t y i e l d s : f o r Groups 1 and 2 combined  81  Genetic group trends o f l i f e t i m e m i l k and l i f e t i m e f a t y i e l d s : f o r Groups 1 and 2 combined  82  Genetic group trends o f l e n g t h o f p r o d u c t i v e l i f e and number of l a c t a t i o n s completed: f o r G r o u p s 1 and 2 c o m b i n e d  83  - x i i-  L I S T OF APPENDICES  Appendix  1  2  3  4  5  6  Page  Year  least  s q u a r e means f o r  Group 1 cows  132  Y e a r l e a s t s q u a r e means f o r Group 2 cows  133  S e a s o n l e a s t s q u a r e means f o r Group 1 a n d Group 2 cows  134  S i r e and e r r o r components o f v a r i a n c e and c o v a r i a n c e  135  Environmental c o r r e l a t i o n s f o r Groups 1 and 2 combined (above d i a g o n a l ) and Group 2 (below d i a g o n a l ) cows  138  E x p e c t e d b r e e d i n g v a l u e s (EBV) o f s i r e s f o r p r o d u c t i o n and longevity t r a i t s  139  - xiii  -  ACKNOWLEDGEMENTS  The  author  wishes t o express  sincere appreciation  t o D r . J o h n Hodges, h i s g r a d u a t e a d v i s o r , encouragement, v a l u a b l e a d v i c e  and g u i d a n c e d u r i n g t h e  r e s e a r c h and i n t h e w r i t i n g o f t h i s is  thesis.  Appreciation  e x t e n d e d t o h i s g r a d u a t e c o m m i t t e e member,  Peterson, during  f o r h i s suggestion  the data  manuscript.  analyses  The a u t h o r  and c o n s t r u c t i v e  S h e l f o r d and Dr. Oscar reviewing  this  The  i s also grateful  Sziklai  author  i s indebted Science,  i n the data  for  their  a s s i s t a n c e i n computer  Appreciation  R. H a r v e y  analyses.  financial  and Mr. Do-Kyu L e e  programming.  d a i r y R.O.P. r e c o r d s .  support  o f the Bangladesh  B a n g l a d e s h t h r o u g h t h e I.D.A. c r e d i t  Agricultural No. 407-BD  acknowledged.  Finally,  the author  and T a s l i m  understanding  Thanks  i s e x t e n d e d t o A g r i c u l t u r e Canada f o r  t o use t h e i r  gratefully  and f o r  O h i o S t a t e U n i v e r s i t y , U.S.A.)  a l s o extended t o Mrs. Mabel S t r i k e r  sons T a n b i r  interest  t o Dr. Walter,  are  University,  to the other  D r . B.D. Owen, Dr. J.A.  for their  whose c o m p u t e r p r o g r a m was u s e d  The  criticism  thesis.  (Department o f D a i r y  permission  D r . R.G.  and t h e p r e p a r a t i o n o f t h i s  members o f h i s g r a d u a t e c o m m i t t e e :  is  f o r h i s constant  wishes t o thank h i s w i f e  K a s t u r y and  f o r t h e e n c o u r a g e m e n t and t h e i r  and p a t i e n c e  during  this  study.  - 1 -  INTRODUCTION  The  p r o f i t a b i l i t y o f a d a i r y cow  r e l a t e d b o t h t o h e r d a i l y and  her  i s closely  lifetime  production.  L i f e t i m e p r o d u c t i o n , even though a r e l i a b l e measure of profitability, in  s h o u l d n o t be u s e d as a c r i t e r i o n o f  merit  a s e l e c t i o n program u n l e s s i t i s a t l e a s t p a r t l y  under  genetic control.  Variable estimates  l i f e t i m e t r a i t s have been r e p o r t e d . (1976) e s t i m a t e d fat  as  .25  and  for  .18  m i l k p e r day  b e t w e e n .28  and  Gill  and  for  Allaire  h e r i t a b i l i t i e s o f l i f e t i m e m i l k and  .26,  (1969) r e p o r t e d  of h e r i t a b i l i t y  r e s p e c t i v e l y , whereas Hargrove e t a l . f o r both t r a i t s .  of l i f e .40  lifetime  reported  (Gill  Heritability  estimates  i n the l i t e r a t u r e  and A l l a i r e ,  1976;  vary  Hargrove e t a l . ,  1969) . It  u s u a l l y t a k e s f r o m one  p r o d u c t i o n f o r a d a i r y cow T h i s v a r i e s w i t h f e e d and of milk.  to repay her  cost of r e a r i n g .  l a b o u r c o s t s , m i l k y i e l d and  Beyond t h a t , m i l k revenue o v e r  c o s t s becomes g r o s s p r o f i t .  value  c o s t s p e r cow,  l a r g e s t cost of milk  i s t h e r e f o r e b e n e f i c i a l by  r e a r i n g c o s t s o v e r more y e a r s . d a i r y c a t t l e may  direct  Annual d e p r e c i a t i o n ranks,  l a b o u r , as t h e t h i r d  A long productive l i f e  in  milk  M o s t cows h a v e p a i d f o r t h e m s e l v e s by t h e age o f  three to f i v e years.  f e e d and  to three years of  production. spreading  Longer average m i l k i n g  i n c r e a s e p r o f i t s by r e d u c i n g  life  replacement  i n c r e a s i n g average herd p r o d u c t i o n ,  r e p l a c e m e n t numbers w h i c h must be r e a r e d , and  after  reducing  creating greater  opportunity Robertson,  for culling  heritability estimate of  of  heritability  Selection because  i s increased,  for longevity  et a l . ,  from 1967;  .05  to  White on  used o n l y w i t h i n  data  one  for length from  i s n o t e x p e c t e d t o be  o f i t s low h e r i t a b i l i t y . for longevity,  I t must  also  i f effective,  the g e n e r a t i o n i n t e r v a l  i f average  thus d e c r e a s i n g the r a t e of  1965;  on m i l k y i e l d  ( S e a t h , 1940; and A l l a i r e  correlation  between y i e l d  from  .80  .48  range  annual  improvement.  lactation  Nichols,  Other e s t i m a t e s  G a a l a a s e s t i m a t e d .15  selection  tend to increase  Selection first  Evans  f r o m a l a r g e number o f dam-daughter p a i r s  recognized that  genetic  Miller  herds w i t h s i r e s  However, Plowman and  h e r d age  component.  an  Many o f t h e s e e s t i m a t e s were b a s e d  o r v e r y few  very e f f e c t i v e  would  c o n c e r n i n g the  (1960) and  i n Holstein  G a a l a a s , 1960;  1965).  many h e r d s .  be  for longevity  (Plowman and  herdlife  and  W i l c o x e t a l . (1957) f o u n d  (1964) o b t a i n e d no g e n e t i c  and N i c h o l s ,  of  have a p p e a r e d  .37, whereas P a r k e r e t a_l.  al.  herd.  reports  of longevity.  et  f r o m one  (Rendel  19 5 0 ) .  Conflicting  .18  f r o m among h e i f e r s  to  Johansson,  and H e n d e r s o n , in first  White  1966).  and  Genetic  later  lactations  ( B a r k e r and R o b e r t s o n ,  1966;  Hargrove  lactation  fifth-lactation  1962;  the  and  1969; and L i n and A l l a i r e , 1978). between f i r s t  occurs mainly during  yields  The  and  phenotypic  et a l . ,  relationship  average herd l i f e  has b e e n f o u n d t o be p o s i t i v e  ranges  to  about  (Van V l e c k ,  1964  - 3 -  Hinks,  1966;  and  G a a l a a s and  Plowman, 1 9 6 3 ) .  t h e r e l a t i o n s h i p i s unknown a l t h o u g h t h a t i t may  not  ( H i n k s , 1966;  i t has  Thereafter, been  i n c r e a s e beyond about the f i f t h  Miller et a l . ,  1967;  W h i t e and  suggested lactation  Nichols,  d e p e n d i n g on p o p u l a t i o n and management r e g i m e s . high y i e l d s  i n the f i r s t  Possibly  l a c t a t i o n are a s s o c i a t e d w i t h  p h y s i c a l or p h y s i o l o g i c a l c h a r a c t e r i s t i c s tending to f u r t h e r increases i n productive or economical Bakels was  (1959) o b s e r v e d  limit  herdlife.  t h a t h e r d l i f e o f German Brown cows  r e d u c e d when t h e i r f i r s t  of m i l k .  1965)  l a c t a t i o n y i e l d e x c e e d e d 3,400 k g  W h i t e and N i c h o l s  (1965) a l s o n o t e d  a decline in  t h e number o f l a c t a t i o n s c o m p l e t e d by H o l s t e i n cows when first  lactation yield  that a high f i r s t  reached  6,300 k g .  l a c t a t i o n y i e l d predisposed  d i s p o s a l f o r reasons other than y i e l d In annual  A.I. breeding  low,  in later  by  animals life.  total  (2) o n l y i f p r e d i c t o r s  p r e d i c t o r s o f l o n g e v i t y can  u s e d when y o u n g b u l l s e n t e r a s t u d o r a t t h e t i m e a progeny t e s t or both  S e l e c t i o n of young b u l l s increase generation  will  c o n s i d e r a b l e g e n e t i c v a r i a t i o n can  (3) o n l y i f t h e s e  achieve  to  thus, s e l e c t i o n f o r long productive l i f e  of l o n g e v i t y possessing  first  reported  female s e l e c t i o n i s  be u s e f u l (1) o n l y i n c h o i c e among s i r e s  f o u n d and  (1966)  system, the percentage of  g e n e t i c improvement a c h i e v e d  relatively  Hinks  their  ( M i l l e r e t aJL.,  However, r e l a t i v e l y  are r e q u i r e d to s i r e the next generation  be  bulls  f r o m o l d e r dams a l s o t e n d s  interval.  be  1967). to  few  of young b u l l s  sires for  - 4 -  A.I.  and t h e r e  longevity  i s scope f o r s e l e c t i o n  from b u l l s  The  with  s i m i l a r l y desirable milk  genetic contribution  improvement c a n b e d e t e r m i n e d breeding  i n the population.  appraisal  i s essential  on  proofs.  things, h i s  length of l i f e  S i n c e an e a r l y  f o r t h e maximum  ofh i s  and a c c u r a t e  genetic  progress,  e v a l u a t i o n o f young s i r e s must be b a s e d a l m o s t first  lactation  survival  daughters milk  performance o f t h e i r  o f t e s t e d daughters  lactations  w o u l d be u s e f u l i n later  stages  of A.I.  sires  Burnside  limited  and W i l t o n  i n subsequent  of their  life,  i n choosing  sires  daughters  culled  and  lactations  later  percentage  annually  of sires  culled  relation  annually Robertson  rating  factors.  of  o f s i r e and  f o r udder problems i n and B a r k e r  between t h e h e i f e r  S u r v i v a l o f s i r e progeny  (1966)  progeny t e s t o f to later  i s a l s o i n f l u e n c e d by o t h e r  H e r d s d i f f e r , i n p r o d u c t i o n , c u l l i n g p o l i c y and i n  used t o breed  cows. The y e a r  areas.  i n second  a b u l l and t h e p r o p o r t i o n o f h i s d a u g h t e r s s u r v i v i n g lactations.  sons  correlation  f o r low m i l k p r o d u c t i o n  lactations.  reported a positive  i n these  and p e r c e n t a g e  a n d .30 between m i l k  o f daughters  s e c o n d and l a t e r  from which  with  program.  information i s available  rating  of sires  a n d when compared  (1970) r e p o r t e d a n e g a t i v e  .47 between m i l k  The  t o measure t h e a c c e p t a n c e  p r o o f s w o u l d be u s e f u l  Only  entirely  daughters.  a r e d e s i r a b l e f o r u s e i n young s i r e t e s t i n g  of  of  of a sire to population  by, among o t h e r  v a l u e and t h e r e l a t i v e  daughters  the  on i n d i c a t o r s  i n w h i c h a cow b e g i n s  sires  her f i r s t  -  l a c t a t i o n may  i n f l u e n c e her  5  -  s u r v i v a l as r e l a t e d t o  economic s i t u a t i o n a t t h a t time. milk proof obtained  and  correlation  h e r d l i f e of t e s t e d daughters should  f r e e from e f f e c t s of herd T h i s r e s e a r c h was  in  Thus t h e  lifetime production  and  the of  be  year-season.  conducted t o examine the d i f f e r e n c e s  and  length of productive  life  of  H o l s t e i n - F r i e s i a n cows i n R e c o r d o f P e r f o r m a n c e h e r d s due herd,  year,  s e a s o n and  genetic  factors.  The  study  to  also  i n v e s t i g a t e d the r e l a t i o n s h i p of e a r l y r e p r o d u c t i v e  performance  and  production  yields  and  l e n g t h of h e r d l i f e .  i n the  first A  r e l a t i o n of s i r e s breeding l i f e t i m e p e r f o r m a n c e , and  lactation with lifetime  f u r t h e r o b j e c t i v e was values  f o r m i l k and  longevity.  to study fat with  the  - 6 -  LITERATURE REVIEW  Longevity  and  The many y e a r s f r o m an  Disposal  ability  are  b o t h t o p r o d u c e and  desirable  e c o n o m i c and  Longevity  in dairy  fertility  and  price  Reasons  characteristics in dairy  possible  of  The  beef a l s o  S t u d i e s t o determine the length  breed  c a t t l e i s the  production.  o f m i l k and  improvement  variation  are  i n the  length  of  i n Table  1.  The  h e r d l i f e of d a i r y  i n great  cow  more d e t a i l e d w i t h r e s p e c t  earlier  are  studies  although  low  (Table  2).  Batra  et a l .  Holstein during study  to natural  of  dairy  (1971) e s t i m a t e d  September indicated  1967  have c o n c l u d e d  the  that  culling  of  herds of  cows have  to  in dairy  t o be  patterns  constant constant  the also  on  dairy  reasons  indicated  constant  of  causes of  annual d i s p o s a l  t o A u g u s t 1968  and  some  than  that  cows, o t h e r f a c t o r s  herds of  different disposal  decreasing  of  life.  the  b r e e d i n g problems are  w a s t a g e and  cows i n r e g i s t e r e d  increasing,  and  s t o c k , and •  Recent r e p o r t s  These s t u d i e s  milk production  main r e a s o n s f o r d i s p o s a l contribute  detail.  health,  cows and  Results  been i n v e s t i g a t e d disposals  standpoint.  of productive  d i s t r i b u t i o n of  summarized  cattle,  demand f o r b r e e d i n g  a f f e c t length  age  for  summation o f g e n e r a l  h e r d l i f e have b e e n e x t e n s i v e .  these studies  to reproduce  the also  herds. rate  of  s i z e i n Canada  19.9%.  Their  i n herds  i n s i z e and s i z e should  of  the  authors  reflect  the  Table 1.  Comparative c u l l i n g r a t e and l e n g t h o f h e r d l i f e i n different countries.  Canada  U.S.  U.K.  Australia  Netherlands Renkema and Stelwagen (1979)  Batra  Andrus  Beynon  et a l . (1971)  et a l . (1970)  (1978)  Amiel and Moodie (1973)  P e r i o d o f Study  1967-68  1962-66  1976-77  1968-69  Breed  Holstein  Holstein  Friesian"'"  Number o f Cows  19,336  199,411  39,454  Reference  Removal (%)  22.1  19.9  Length o f H e r d l i f e ( y r s )  1  87% o f t h e herds were F r i e s i a n s  2  Number o f l a c t a t i o n s completed.  3.08  4.8  i  Friesian 2,610 22 4.2'  22 4.5  T a b l e 2.  Summary o f r e c e n t r e s e a r c h on d a i r y c o w . d i s p o s a l s .  Reference White and Nichols (1965)  Burnside et a l . (1971)  Reasons f o r Disposal  Hargrove et a l . (1969)  Period  1949-66  1958-63  1967-68  Breed  Holstein  Holstein  Holstein  7,317  19,336  Number o f Cows  1,861 _  _  - -  Amiel and Moodie (1973)  1968-69  Spooner (1978)  1975-78 Friesian  2,610  2,936  ( i n per cent) —  2  9.6  25.8  7.7  30.3  15.7  20.8  16.0  34.7  22.1  36.9  15.5  16. 4  20.7  Mammary S y s t e m  2.9  13. 5  10.2  5.2  8.7  Type  0.8  0.4  9.4  Mastitis  8.0  5.8  5.4  11.1  13. 8  23.4  18.5  21.9  34. 2  10.5  Purpose  Breeding Milk  Problems  Production  Other reasons  3  I CO  f i n  12.4  Dairy  1  11.6  1  T o t a l number o f a n i m a l s c u l l e d .  2  I n c l u d e s s u r p l u s and a n i m a l s r e a r e d f o r s a l e .  3  I n c l u d e a b o r t i o n , f o o t and l e g p r o b l e m s , c a l v i n g p r o b l e m s , i n j u r y and hardware d i s e a s e , p r o b l e m c o w s , o l d age and d e a t h .  I  -  9  -  typical disposal pattern.  Burnside  e t a l . (1971),  using  data o f Canadian Record of Performance herds f o r the p e r i o d 1967-68 f o u n d r e p r o d u c t i o n  and low m i l k p r o d u c t i o n  major causes o f v o l u n t a r y herd for to for  removals.  were  Cows c u l l e d  annually  t h e s e p r o b l e m s r a n g e d f r o m 13.4% t o 24.4% and f r o m 1 5 . 5 % 28.3%, r e s p e c t i v e l y . low p r o d u c t i o n  Young cows w e r e c u l l e d more h e a v i l y  t h a n t h e i r o l d e r h e r d m a t e s , w h e r e a s more o f  t h e o l d e r cows w e r e r e m o v e d f o r weakness i n udders. trends  Reports from other  i n c u l l i n g r a t e b y age o f cows  Johansson claimed traits  reproduction, diseases c o u n t r i e s show  (Tabel  (1962) and W h i t e and N i c h o l s  3).  and similar  Seath  (1940),  (1965) h a v e a l s o  t h a t most o f t h e e f f e c t i v e s e l e c t i o n f o r p r o d u c t i o n i s p r a c t i s e d e a r l y i n an a n i m a l ' s  life  and t h a t  farmers  a r e more c o n c e r n e d t h e r e a f t e r w i t h t h e c o n t r o l o f d i s e a s e w i t h the maintenance o f breeding Allaire  efficiency.  A study  and  by  e t a l _ . (1976) showed a d i f f e r e n t t r e n d i n c u l l i n g  r e a s o n by age o f cows. primary  They r e p o r t e d  t h a t most  reasons f o r removal p r i o r t o 2 years  disease,  type,  and r e p r o d u c t i o n .  frequent  o f age w e r e  I n - l a t e r ages,  production,  m a s t i t i s a n d g e n e r a l h e a l t h a c c o u n t e d f o r most o f t h e c u l l i n g decisions. occurred  P r o p o r t i o n a t e l y , most r e m o v a l s f o r low r e p r o d u c t i o n  during  2 t o 3 y e a r s , most r e m o v a l s f o r low p r o d u c t i o n  during  3 t o 4 y e a r s , m o s t r e m o v a l s due t o m i l k i n g  during  5 to 6 years,  occurred  after  and most r e m o v a l s f o r g e n e r a l  10 y e a r s  d i s e a s e was d u r i n g  first  o f age.  The c r i t i c a l  5 months o f  life.  characteristics health  age f o r  Table  3.  Disposal reasons  by l a c t a t i o n  number when d i s p o s e d . Reference  Reasons f o r Disposal  Lactation  Burnside  Number  et a l . (1971)  0 Conner and Hodges - . • (1963) 1  1957-60  1967-68 Holstein 19,336  Period Breed Number o f Cows Production  Breeding  Mammary  Dairy  System  Purpose  Diseases  1 2 3  Problems  (1978) 1975-78 Friesian 2,936 2  o  —  Milk  Spooner  1 2 3+  22.0 19.1 11.8  24.5 38.9 18.4  26.6 32.8 17.7  1 2 3+  15.1 17.6 24.2  4.4 13.1 10. 3  37.9 36.0 34.0  1 2 3+  8.1 8.1 11.8  1 2 3+  34.6 35.7 19.1  38.9 20.7 10.6  14.4  1 2 3+  3.9 4.9 8.7  13. 8 13.1 15.4  10.8 8.7 16.8  P e r c e n t a g e s o f numbers d i s p o s e d f o r a l l r e a s o n s . T o t a l number o f a n i m a l s c u l l e d . I n c l u d e s s u r p l u s and a n i m a l s r e a r e d f o r s a l e .  6. 0 —  10.3 5.5 J  - 11 -  Spooner  (197 8) o b s e r v e d b r e e d i n g p r o b l e m s ,  p a r t i c u l a r l y t h e f a i l u r e t o c o n c e i v e were o f m a j o r i n c u l l i n g d e c i s i o n s a t a l l a g e s , and t h a t diseases, including mastitis as t h e a n i m a l g o t  importance  infectious  became o f i n c r e a s i n g  importance  older.  S o u r c e s o f V a r i a t i o n i n L i f e t i m e P r o d u c t i o n and L o n g e v i t y  The  sources of v a r i a t i o n which a f f e c t  lifetime  p r o d u c t i o n and l o n g e v i t y i n d a i r y cows h a v e b e e n t h e s e i n c l u d e b r e e d , age a t f i r s t h e r d management and and b e e f p r i c e s ,  established,  calving, calving  interval,  l e v e l o f p r o d u c t i o n , y e a r l y change i n m i l k  s e a s o n o f c a l v i n g and g e n e t i c f a c t o r s .  Breed  S i g n i f i c a n t i n t e r a c t i o n b e t w e e n b r e e d s and d i s p o s a l r e a s o n s was O'Bleness  o b s e r v e d by B u r n s i d e e t a l . ( 1 9 7 1 ) ,  and Van V l e c k  relatively  (1962).  Burnside e t a l .  noted  and that  lower p e r c e n t a g e o f J e r s e y s were c u l l e d f o r  b r e e d i n g problems  and h i g h e r p e r c e n t a g e c u l l e d  p r o d u c t i o n , whereas r e l a t i v e l y were c u l l e d  major  f o r low  lower percentage of  Holsteins  f o r l o w p r o d u c t i o n and h i g h e r p e r c e n t a g e f o r  mammary s y s t e m p r o b l e m s .  Highest i n c i d e n c e of  because of r e p r o d u c t i v e problems c l o s e l y by H o l s t e i n s .  disposal  were i n Guernseys,  followed  S i m i l a r breed d i f f e r e n c e s were  also  - 12 -  o b s e r v e d by O ' B l e n e s s and Van V l e c k . incidence of milk  A r e l a t i v e l y high  fever deaths i n Jerseys  compared t o o t h e r  b r e e d s w e r e o b s e r v e d by b o t h t h e g r o u p s o f w o r k e r s . difference  i n the length of productive  Andrus e t a l . (1970). Holstein,  They e s t i m a t e d  life life  Breed  was o b s e r v e d b y expectency of  J e r s e y , G u e r n s e y a n d A y r s h i r e a s 3.08, 3.20, 3.17  and  2.93 y e a r s ,  Age  at f i r s t  calving  First but w i t h i n  respectively.  l a c t a t i o n y i e l d i n c r e a s e s w i t h age a t c a l v i n g ,  the l i m i t s normally  e n c o u n t e r e d i n p r a c t i c e , age  a t c a l v i n g does n o t have a marked e f f e c t on e i t h e r y i e l d s o f milk or fat.  Lamb a n d K o p l a n d  (1963) o b s e r v e d t h a t cows  f r e s h e n i n g a t 25 m o n t h s o f age h a d t h e h i g h e s t p r o d u c t i o n o f m i l k and m i l k f a t p e r day o f l i f e , decreasing months. first 27  a s t h e age a t f i r s t  Highest  total  with production  freshening increased past  a n d 28 m o n t h s o f a g e . phenotypic  o f age a t f i r s t  t h e number o f l a c t a t i o n s i n i t i a t e d , p r o d u c t i v e  had  Cows c a l v i n g  more d a y s o p e n a n d , c o n s e q u e n t l y ,  3 05 d a y s i n m i l k  freshening at  H a r g r o v e e t a l . (1969)  correlations  number o f d a y s i n m i l k .  25  l i f e t i m e p r o d u c t i o n was made by cows  f r e s h e n i n g a t 30 m o n t h s f o l l o w e d by t h o s e  negative  p e r day  later i n life.  obtained calving  life  with  and t o t a l  late f o r the f i r s t more p r o d u c t i o n  Optimum age a t f i r s t  time  after calving  w h i c h m a x i m i z e d l i f e t i m e m i l k p r o d u c t i o n was 27 m o n t h s f o r  - 13 -  Holstein.  P u r i and Sharma  (1965) o b t a i n e d a h i g h l y -  s i g n i f i c a n t n e g a t i v e c o r r e l a t i o n b e t w e e n age a t c a l v i n g and y i e l d s i n f i r s t  two l a c t a t i o n s  first  (-.55) i n Zebu  cows.  Calving  interval  Lamb a n d K o p l a n d b e t w e e n 12 a n d 13 months of l i f e , months  resulted  stayed i n the herd  less milk  l o n g e r and a c h i e v e d a h i g h e r l i f e t i m e within  t h e h e r d had  i n t e r v a l s than t h e i r contemporaries  ( M i l l e r e t a_l. , 1967) .  association  interval  i n t e r v a l b e t w e e n 13 a n d 15  The h i g h e s t p r o d u c e r s  average c a l v i n g  calving  i n h i g h e s t p r o d u c t i o n p e r day  w h e r e a s cows w i t h c a l v i n g  production.  as e n v i r o n m e n t a l ,  c u l l i n g o f low producers partly  (1963) o b s e r v e d  producing  They e x p l a i n e d t h i s  p a r t l y due t o more i n t e n s e  that  do n o t b r e e d  r i g h t back and  due t o cows i n h i g h p r o d u c t i o n n o t r e t u r n i n g  as q u i c k l y  a f t e r p a r t u r i t i o n as l o w e r p r o d u c e r s .  obtained phenotypic  and g e n e t i c c o r r e l a t i o n s  i n t e r v a l and m i l k p r o d u c t i o n r a n g i n g from .43 t o .65, r e s p e c t i v e l y .  Phenotypic  l e n g t h o f h e r d l i f e and c a l v i n g whereas g e n e t i c c o r r e l a t i o n s Interpretation terminal  to estrus They  between  calving  .19 t o .21 a n d  correlations  between  i n t e r v a l were e s s e n t i a l l y z e r o ,  varied  between  of these r e l a t i o n s h i p s  .24 a n d  is difficult,  l a c t a t i o n does n o t r e s u l t i n a c a l v i n g  measurement.  longer  .72. because the  interval  - 14 -  E v e r e t t e t a l . (1966) a l s o o b t a i n e d b e t w e e n 120-day m i l k p r o d u c t i o n Holstein  (.46), b u t t h e y  correlation estimated  found a low n e g a t i v e  and y e a r  correlation  and c a l v i n g i n t e r v a l i n  (-.04) b e t w e e n t h e s e  i n t r a herd  a high genetic  variables.  phenotypic Rennie  (1956)  l i n e a r r e g r e s s i o n s o f m i l k and  f a t y i e l d s on l e n g t h o f c u r r e n t c a l v i n g i n t e r v a l a s 33.3 k g o f m i l k a n d 1.1 k g o f f a t , p e r 10 d a y s a n d f o r p r e c e d i n g c a l v i n g i n t e r v a l a s 27.6 k g o f m i l k and 1.04 k g o f f a t , p e r 10 d a y s i n c r e a s e i n c a l v i n g i n t e r v a l . The v a r i a t i o n mainly  i n the length of c a l v i n g i n t e r v a l i s  due t o v a r i a t i o n i n t h e number o f d a y s o p e n .  of days  open on m i l k p r o d u c t i o n  S m i t h and L e g a t e s  (19 62)  have been s t u d i e d e x t e n s i v e l y .  reported  during the l a c t a t i o n s i g n i f i c a n t l y y i e l d b u t n o t 90-day m i l k y i e l d .  t h a t number o f d a y s  open  i n f l u e n c e d 305-day  milk  T h i s was e x p l a i n e d  largely to the influence of gestation. concluded  a s due  W i l t o n e t a l . (1967)  t h a t t h e e f f e c t o f d a y s open on t h e r e c o r d s o f  i n d i v i d u a l cows i s more i m p o r t a n t proofs, since there  is little  t h a n t h e e f f e c t on s i r e  c h a n c e f o r t h e e f f e c t s t o be  r a n d o m i z e d f o r a s i n g l e cow; t h u s ,  adjustment of records f o r  d a y s open i n b r o o d cow e v a l u a t i o n seems a d v i s i b l e . and Henderson production  Effects  Schaeffer  (1972) s t a t e d t h a t e f f e c t s o f d a y s open on m i l k  i s l a r g e l y environmental,  305-day r e c o r d s  thus, adjustment o f  f o r d a y s open a p p e a r s n e c e s s a r y  and w o u l d n o t  i n t r o d u c e g e n e t i c b i a s , because t h e h e r i t a b i l i t y o f days open was f o u n d t o be e s s e n t i a l l y  zero.  - 15  -  Season of c a l v i n g  Cows f r e s h e n i n g i n t h e c o n s i d e r a b l y more m i l k t h a n s p r i n g and winter in  summer.  Lee  fall  those  e t 'al.  and  early winter  freshening i n late  produce winter,  (1961) f o u n d cows c a l v i n g i n  (December t o F e b r u a r y ) and  s p r i n g ( M a r c h t o May)  months  S o u t h West U n i t e d S t a t e s p r o d u c e d s i g n i f i c a n t l y more m i l k ,  F.C.M. and August). and  f a t than  cows c a l v i n g i n summer m o n t h s  O t h e r s t u d i e s i n S o u t h West U n i t e d  Welch  (1960) and  J:ohnston e t a l . (1956)  t h a t cows c a l v i n g i n w i n t e r and average p r o d u c t i o n .  Gacula  S t a t e s by F o s g a t e have i n d i c a t e d  e a r l y s p r i n g have the  e t a l . (1968) o b s e r v e d  yield  o f f a t i n December t o May  Annis  e t a l _ . (1959) r e p o r t e d  (June t o  higher  i n Pensylvania dairy  l o w e r m i l k and  highest  herds.  fat yields  in  June t o September i n c o m p a r i s o n t o o t h e r c a l e n d a r months f o r Washington d a i r y herds.  Wunder and M c G i l l i a r d  cows c a l v i n g a t a g e s 3 o r 4 y e a r s a f f e c t e d by c a l v i n g i n J u l y and in  Michigan  c a l v i n g was  H o l s t e i n herds.  and  (19 67)  o v e r w e r e more  A u g u s t than were  The  observed adversely  2-year-olds  i n f l u e n c e of season of  n e a r l y t h e same f o r cows o f d i f f e r e n t a g e s d u r i n g  September t o D e c e m b e r /  Miller  e t a l . (1970) a l s o  observed  o l d e r cows w e r e more s e v e r e l y a f f e c t e d by  summer c a l v i n g t h a n  first  East United  l a c t a t i o n H o l s t e i n h e i f e r s i n North  Maximum m i l k p r o d u c t i o n was w i n t e r c a l v i n g a t a l l ages. records  s h o u l d be  adjusted  achieved  by  late f a l l  They suggested f o r both  that  s e a s o n and  age  and  States. early  lactation of c a l v i n g  -  16  -  simultaneously using m u l t i p l i c a t i v e Mao  factors.  e t a_l. (1974) o b s e r v e d  monthly v a r i a t i o n  i n milk y i e l d  a c o n s i s t e n t p a t t e r n of  i n Canadian Record  Performance herds.  Summer c a l v e r s p r o d u c e d  calvers  groups.  f o r a l l age  of c a l v i n g for  age  interaction  and  season  using B r i t i s h freshened fat  and  (April  Columbia  t o September).  l a c t a t i o n milk  and and  Survival  suggested  than  i s necessary.  t o March) had  fat yields  Kinks  considerable  seasonal d i f f e r e n c e s ,  h i g h e r average  observed  to  account  i n the  d e p e n d i n g on  (1966) s t a t e d t h a t , s i n c e t h e r e summer c a l v i n g  calving  herdmates,  i f they  milk,  i n summer  first  Ahunu,1978). the  season  are cows must  demonstrate c o n s i d e r a b l y g r e a t e r p r o d u c t i v e m e r i t than winter  month  (197 8)  ( G a c u l a e t aJL. , 1968;  of calving.  by  cows w h i c h  variation  also d i f f e r  winter  adjustment  those which freshened  of the t o t a l  r a t e may  age  Ahunu  found  S e a s o n e f f e c t was  1.9%  than  that joint  D.H.I.A. r e c o r d s  (October  protein yields  .3%  They a l s o o b s e r v e d  at calving  i n winter  f o r between  and  less  of  their  a r e t o have e q u a l c h a n c e s  of  survival. Reports o f the season in  nature,  w o u l d be  i n the  of calving  thus,  specific  literature  indicate  on m i l k and  correction  for their  for that region.  t h a t the i n f l u e n c e  fat yields effects  on  are r e g i o n a l records  -  Year of  17  calving  P r o d u c t i o n and to  year  d e p e n d i n g on  t h e h e r d , m i l k and and in  culling  r a t e may  differ  beef  y e a r l y m i l k and  progress 1953  t o 1961  progress 1.1  kg  Van  Vleck  price,  demand f o r b r e e d i n g  (Verde  kg.  The  Legates  ( B u r n s i d e and  as  Gacula 128  kg  Estimated  and  Legates,  124  1957-1969  1.1  f a t d u r i n g 1966-1972  41.8  kg m i l k  1975)/  53  and  kg m i l k  ( P o w e l l and  1.26  kg  55 kg m i l k  kg,  partly  (Ahunu,  annual  -.7  kg  for Holstein f a t during  45 k g m i l k d u r i n g kg m i l k  (Kennedy and  Legates,  due  t o improved f e e d i n g  and  Freeman, 1974);  and  1978).  i s probably  genetic trends  kg m i l k and  82  and  respectively.  1971)  1953-1961  1.5 46  kg f a t  kg m i l k  Moxley,  f a t d u r i n g 1958-1972  (Hargrave  ( H i n t z e t a l . , 1978).  kg m i l k  trend observed  annual  1967);  annual  of y e a r l y  e t a_l. (1968) r e p o r t e d  e t a l . , 1972);  during kg  (1967) e s t i m a t e d  e t a l . , 1 9 7 2 ) , and  p o p u l a t i o n s r e p o r t e d a r e : 33 (Verde  trends  for Holstein during period  p a r t t o g e n e t i c improvement and  1958-1967  stock  Upward  More r e c e n t e s t i m a t e s  upward p h e n o t y p i c  and management.  time.  l a c t a t i o n y i e l d s were 90  (1966) and i n milk  and  lactation milk  63  in first  fat  progress  as  year  f a t y i e l d s have' b e e n r e p o r t e d by many  Burnside  in first  from  f e e d i n g , management, h e a l t h s t a t u s o f  o t h e r f a c t o r s which might vary with  researchers.  in  -  and  1975);  (Schaeffer et a l . , and  26  kg  milk  - 18  -  Herd  H e r d s may of production  and  d i f f e r i n f e e d i n g and culling policies.  management, i n l e v e l  Herds a l s o d i f f e r i n  s i r e s u s e d t o b r e e d cows; c o m m e r c i a l m i l k h e r d s may use  sires with high milk ratings  c h o o s e s s i r e s w i t h h i g h m i l k and  while a purebred type p r o o f s .  tend  to  breeder  Burnside  and  Wilton  (1970) o b s e r v e d t h a t h i g h e r p e r c e n t a g e s o f cows w e r e  culled  f o r poor type  i n the herds of higher production  levels.  They a l s o o b s e r v e d a d e c r e a s e i n t h e number o f cows c u l l e d low p r o d u c t i o n w i t h t h e i n c r e a s e i n h e r d Hinks  (1966) r e p o r t e d a g r e a t e r s e l e c t i o n  y i e l d i n t h e low y i e l d i n g herds.  He  concluded  e n v i r o n m e n t had  animals  to display  in higher y i e l d i n g  27.8%  t o 34.0%  i n m i l k and 1965; The  Van  only  and  pressure  i n the poorer  for milk yielding  productive  greater individual  merit  of t h e i r  i f their  contemporaries  herds.  Most s t u d i e s i n d i c a t e d of v a r i a t i o n  production.  herds compared t o h i g h  chances o f s u r v i v a l were t o match those  source  l e v e l of  for  herd  as t h e m o s t  in lactation yields f r o m 26.6%  fat yields,  t o 31.7%  respectively  V l e c k e t a l . , 1961;  and  of the t o t a l ( B e r e s k i n and  lower  estimates  i s by  G a c u l a e t a l . ( 1 9 6 8 ) , who  obtained  15.9%  f o r m i l k and  respectively.  fat yields,  accounted  V e r d e e t a l . , 1972;  study which r e p o r t e d  important  variation Freeman,  and  of herd  estimates  from  Ahunu, 1 9 7 8 ) . effect  10.3%  and  - 19 -  Heritability  E s t i m a t e s o f F i r s t L a c t a t i o n M i l k and F a t Y i e l d s  Heritability a r e numerous.  Lasley  .36 f o r m i l k y i e l d  estimates  o f m i l k and f a t p r o d u c t i o n  (1963) l i s t s  and  average estimates  .4 f o r f a t y i e l d  such r e p o r t s , r e s p e c t i v e l y .  of  b a s e d on 30 and  These e s t i m a t e s  17  v a r i e d depending  u p o n p o p u l a t i o n and t h e method o f e s t i m a t i o n .  Those u s i n g  d a u g h t e r - d a m r e g r e s s i o n r a n g e d f r o m .29 t o .45 f o r m i l k yield  ( B r a d f o r d and Van V l e c k ,  Van V l e c k and B r a d f o r d , et  a l . , 1969),  ranged from  .12 t o .37  Rendel e t a l . ,  1965; Van V l e c k ,  whereas e s t i m a t e s  19 66; and  from h a l f - s i b  ( G a c u l a e t aJL. , 1968;  1976; V a n V l e c k , 1966;  ranged from  and  and  Allaire,  .14  to..45  ( G a c u l a e t a l . , 1968;  Gill  1975  u s i n g d a u g h t e r - d a m r e g r e s s i o n and  and A h u n u , 1978)  half-sib  1978).  (Hargrove e t a l . ,  from  and A l l a i r e , 1976;  Hargrove  and A h u n u ,  .18 t o .37  and B e r e s k i n and F r e e m a n , 1965)  1957;  correlation  Gill  S c h a e f f e r e t a l . , 1975;  Estimates f o r f a t y i e l d 1969;  1964;  Schaeffer et a l . ,  correlation, respectively.  R e l a t i o n s h i p B e t w e e n F i r s t and L a t e r L a c t a t i o n s  The  first  lactation  r e c o r d i s most u s e f u l f o r e a r l y  culling  and f o r p r o v i n g  records  a r e o f more c o n c e r n when e s t i m a t i n g b r e e d i n g v a l u e s  t h e cows. third  Heritability  lactation  A.I. bulls,  estimates  t h e s e c o n d and  of the f i r s t ,  yields reported i n l i t e r a t u r e  third  second  differ  of  and  from  each  - 20 -  other  (Freeman,  196 0; J o h n s o n  and C o r l e y , 1961; B a r r and  Van V l e c k , 1 9 6 3 ; M a r t o j o e t a l . , J o h a n s s o n and Hansson, s t u d i e s seem heritable (milk fat  1963; R e n d e l e t a l . , 1957;  1940; and J o h a n s s o n ,  to indicate the f i r s t  1955).  r e c o r d s a r e more  ( m i l k .26 t o .36, f a t .25 t o .43) t h a n  .22 t o .27, f a t .14 t o .35) a n d t h i r d  second  ( m i l k .21 t o . 3 3 ,  .16 t o . 2 6 ) , a n d t h a t t h e s e c o n d a n d t h i r d  almost e q u a l l y h e r i t a b l e .  The U.S.  records are  R e s u l t s r e p o r t e d from  Europe  g e n e r a l l y show t h e s e c o n d r e c o r d t o be l e s s r e l i a b l e . findings justify  the early c u l l i n g  b u l l s on t h e i r d a u g h t e r s f i r s t  These  and t h e s e l e c t i o n o f A . I .  l a c t a t i o n , provided the f i r s t  r e c o r d i s a l s o as a c c u r a t e as l a t e r r e c o r d s f o r i n d i c a t i n g the breeding values Lush  (1964)  i n later  lactations.  M o l i n u e v o and  i n d i c a t e d t h a t s e l e c t i n g dams on t h e i r f i r s t  w o u l d be a t l e a s t a s e f f e c t i v e f o r i m p r o v i n g o f t h e d a u g h t e r s i n t h e i r s e c o n d and t h i r d  the production  l a c t a t i o n s as  s e l e c t i n g t h e dams on t h e i r s e c o n d a n d t h i r d r e c o r d s . supported  by t h e f i n d i n g s o f Freeman  (1960)  records  This i s  and Van V l e c k  (1964).  Freeman r e p o r t e d h i g h e r g e n e t i c c o r r e l a t i o n s between f i r s t and second l a c t a t i o n m i l k  (.68) a n d f a t (.8) c o m p a r e d t o  c o r r e l a t i o n s between f i r s t  and t h i r d o r s e c o n d a n d t h i r d (.4).  Van V l e c k a l s o f o u n d h i g h g e n e t i c c o r r e l a t i o n s between t h e first  and l a t e r  l a c t a t i o n records  (.66 t o .96) i n d i f f e r e n t  breeds.  The f i r s t  to  lactation records, i s unlikely  later  l a c t a t i o n r e c o r d though h i g h l y c o r r e l a t e d to give information  about o t h e r c h a r a c t e r i s t i c s , such as udder attachment o r l o n g e v i t y , w h i c h do n o t become c l e a r l y m a n i f e s t e d  until  later  in  life.  Inheritance of Longevity  Longevity with dairy cattle,  and L i f e t i m e  Production  i s d e f i n e d as l e n g t h o f l i f e . this definition  I n usage  i s often qualified to  denote t h e l e n g t h o f t h e p r o d u c t i v e  life  ( P a r k e r e t a l . , 19 6 0 ) .  S e v e r a l w r i t e r s have s u g g e s t e d t h e i m p o r t a n c e o f i n c r e a s i n g l o n g e v i t y , b o t h from t h e economic s t a n d p o i n t  and b e c a u s e i t  a f f e c t s the p o s s i b i l i t i e s of improving  the breed  1930;  Conflicting  Gilmore,  1952; a n d L u s h , 1 9 4 5 ) .  have appeared c o n c e r n i n g Estimates  the h e r i t a b i l i t y  of h e r i t a b i l i t y  Parker  reports  of longevity.  f o r l o n g e v i t y measured i n a v a r i e t y  o f ways have r a n g e d f r o m 0.0 t o .37 w i t h v a l u e s most f r e q u e n t  (Frazer,  near  .15 b e i n g  (Evans e t a l . , 1964; M i l l e r et. aJL. , 1967 ;  e t a^. , 1960; Plowman a n d G a a l a a s , 1960 ; W h i t e and  Nichols,  1965; W i l c o x  et a l . , 1957; H a r g r o v e et a l . , 1969;  and  and A l l a i r e ,  1976).  in  Gill  one h e r d ,  Wilcox  e t a_l. s t u d y i n g  data  f o u n d a h e r i t a b i l i t y o f .37 f o r t h e number o f  successful parturitions.  Parker  e t al_. , however, found  almost  no e v i d e n c e o f a g e n e t i c b a s i s f o r l o n g e v i t y i n t h e B e l t s v i l l e herd. in  I t seems p r o b a b l e  these  that a t least part of the differences  r e s u l t s c o u l d be due t o c e r t a i n management  s e l e c t i o n procedures i n the v a r i o u s herds. w e r e made u s i n g r e c o r d s  and/or  Early studies  f r o m one o r a few h e r d s ,  w e r e l i m i t e d by s p e c i f i c management a n d d i s e a s e  and i n f e r e n c e s conditions  - 22  and  by  s m a l l numbers o f a n i m a l s .  however, used f a i r l y estimated  t h e h e r i t a b i l i t y o f age  been r e p o r t e d  estimates  l e n g t h of p r o d u c t i o n  They o b t a i n e d to  .26  and  heritability  and  m i l k p e r day  1969;  .28  to  Gill  and  a t l a s t c a l v i n g as .15;.'.. of h e r i t a b i l i t y  and  estimates  have  compared t o l e n g t h  l i f e m e a s u r e d as number o f l a c t a t i o n s ,  Hargrove e t a l . ,  Gaalaas,  i n many h e r d s  for lifetime production  f r e s h e n i n g and  .18  Plowman and  extensive data  R e l a t i v e l y higher  herd  -  life  age  at  last  (Evans e t a l . ,  Allaire, ranging  of  1964;  1976). from  .18  to  .4 f o r l i f e t i m e m i l k , l i f e t i m e f a t  .25, and  of l i f e , r e s p e c t i v e l y .  R e l a t i o n s h i p s of F i r s t L a c t a t i o n Y i e l d s With L i f e t i m e P e r f o r m a n c e and L o n g e v i t y  In the progeny t e s t i n g of d a i r y b u l l s , r e l i a n c e has  t o be p l a c e d on t h e  of t h e i r daughters.  This  needed t o t e s t a b u l l . h e r d l i f e and  first  first  lactation  Since  the g e n e t i c c o r r e l a t i o n  for high milk production,  intense selection for milk production  for  hampered due  t o a decrease i n the  milk production  i n the next  between  would  daughters.  causes a  sharp  increase i n the r a t e of i n v o l u n t a r y c u l l i n g , progress be  time  i s high, selecting  r e s u l t i n an i n c r e a s e i n a v e r a g e h e r d l i f e o f If  performance  i s i n e v i t a b l e because of the  lactation milk yield  bulls for genetic merit  considerable  will  i n t e n s i t y of s e l e c t i o n  generation.  - 23 -  Some r e p o r t s i n t h e l i t e r a t u r e  (Hickman a n d  H e n d e r s o n , 1955; a n d V a n V l e c k ,  1964) have i n d i c a t e d  high f i r s t  i s positively  lactation  production  with length of herdlife. small but highly  and f o r J e r s e y s  in a Beltsville  correlations  They r e p o r t e d h i g h l y  between f i r s t  and b e t w e e n f i r s t  lactation  of Mature E q u i v a l e n t production  (.22  R o b e r t s o n and B a r k e r between f i r s t lactation of f i r s t  life  age  age  (1966) r e p o r t e d  (.179)  (.188). correlations lifetime  on t h e g e n e t i c  l a c t a t i o n and l i f e t i m e the genetic  l a c t a t i o n m i l k and s u r v i v a l  a s .71 i n H o l s t e i n .  to the  They o b t a i n e d  measurements. correlation fifth  genetic  correlations  l a c t a t i o n m i l k w i t h l i f e t i m e m i l k and l e n g t h o f  productive first  (1963) u s i n g  t o .45).  Limited information i s available between f i r s t  Similar  lactation milk with  and l e n g t h o f h e r d l i f e  correlation  Holstein  f a t and f i n a l  s l i g h t l y higher  (ME) f i r s t  for  significant  l a c t a t i o n m i l k and f i n a l  E v a n s e t a l . (1964) r e p o r t e d  first  herd.  r e s u l t s w e r e r e p o r t e d by G a a l a a s and Plowman d a t a f r o m 79 h e r d s .  estimated  between  a n d age a t l a s t c a l v i n g (.19)  associated  e t aJL. (1960)  significant correlations  lactation production (.18)  Parker  that  life  lactation  a s .85 and  .76, r e s p e c t i v e l y ;  and t h a t o f  f a t w i t h l i f e t i m e f a t and l e n g t h o f  a s .94 a n d .84, r e s p e c t i v e l y .  number o f l a c t a t i o n s  Genetic  completed with f i r s t  f a t were  .62 a n d .72, r e s p e c t i v e l y  studies,  h o w e v e r , showed a d i f f e r e n t  productive  correlations  lactation milk  of and  i n t h e same s t u d y . O t h e r trend i n the  relationship  - 24 -  of f i r s t  l a c t a t i o n and l i f e t i m e performance.  Bakels  (1959)  observed a r e d u c t i o n i n the l e n g t h of h e r d l i f e of German Brown cows when t h e i r f i r s t  l a c t a t i o n m i l k exceeded  3,4 00 kg.  White and N i c h o l s (1965) a l s o noted a d e c l i n e i n the number of l a c t a t i o n s  completed  by H o l s t e i n cows when t h e i r  l a c t a t i o n y i e l d reached 6,300 kg. predisposed B r i t i s h F r i e s i a n  High f i r s t  first  lactation  yield  cows t o d i s p o s a l f o r reasons  other than y i e l d i n the l a t e r stages of l i f e  (Hinks, 1966).  R e l a t i o n s h i p o f S i r e Breeding Value and S u r v i v a l of Tested Daughters  The average l e n g t h o f l i f e o f a b u l l ' s daughters i s probably the b e s t o v e r a l l assessment judged by the farmers who  of h i s breeding m e r i t as  are a c t u a l l y m i l k i n g the  (Robertson and Barker, 1966).  daughters  Thus, i t would be u s e f u l to  know the l e n g t h of h e r d l i f e and p r o d u c t i o n subsequent l a c t a t i o n of the t e s t e d daughters.  to  first  Average l e n g t h of daughter's  p r o d u c t i v e l i f e would measure the acceptance of daughters by t h e i r owners and when compared w i t h the m i l k p r o o f s c o u l d be v a l u a b l e i n choosing s i r e s from which sons are d e s i r e d f o r use i n young s i r e t e s t i n g program. is  a v a i l a b l e on s i r e progeny  Very l i m i t e d i n f o r m a t i o n  d i s p o s a l r a t e and  relation  between s i r e b r e e d i n g v a l u e f o r m i l k and the l e n g t h of h e r d l i f e o f t h e i r daughters. reported a negative c o r r e l a t i o n  Burnside and W i l t o n (1970) of . 47 between m i l k r a t i n g s of s i r e s  and percentages of daughters c u l l e d a n n u a l l y f o r low m i l k  - 25  production of  i n second  or l a t e r  .3 between m i l k r a t i n g s  daughters later  culled  daughters  herds,  Schaeffer .39  They have a l s o  and  Robertson  and  Barker  to  Burnside  .44  correlation  percentages  indicated  of  that,  and  s i r e s w i t h m i l k and  .31  surviving  .34  have  f o r low  of a b u l l  to l a t e r  (1974) c a l c u l a t e d to  than  milk  a  positive  and  lactations.  correlations  for survival  or  in  (1966) have f o u n d  progeny t e s t  of h i s daughters and  a  s i r e s w i t h h i g h m i l k r a t i n g s may  between t h e h e i f e r  proportion  from  of s i r e s  and  c u l l e d more f r e q u e n t l y f o r t y p e  production. relation  lactations  a n n u a l l y f o r udder problems i n second  lactations.  registered  -  ranging  r a t e proofs of  type p r o o f s , r e s p e c t i v e l y  and  concluded  t h a t improvement i n s u r v i v a b i l i t y  of daughters  o b t a i n e d by  h i g h f o r b o t h m i l k and  proofs.  using bulls  E v e r e t t e t al_.  correlations 48,  60,  72  .99).  of and  84 months o f age  among s t a y a b i l i t i e s  They have c o n c l u d e d  stayability,  and (.27  "stayabilities" to  .55)  and  at d i f f e r e n t  i f s i r e s must be  4 8-month s t a y a b i l i t y w o u l d be  e v a l u a t e d at a younger  type  (.36 age.  to  .99)  and  to  36,  high genetic  ages  (.58  selected desirable  i t s high genetic correlations with production older stayabilities  be  (1976) o b t a i n e d m o d e r a t e g e n e t i c  between m i l k y i e l d  and  correlations  t h a t rank  could  to  on because  (.32  because b u l l s  to can  .41) be  - 26 -  MATERIALS AND METHODS  Source and D e s c r i p t i o n o f Data  Data used i n t h i s s t u d y were o b t a i n e d from t h e H o l s t e i n Record o f Performance  (R.O.P.) d a t a f i l e  and were  made a v a i l a b l e f o r r e s e a r c h t h r o u g h t h e c o u r t e s y o f A g r i c u l t u r e Canada.  The C a n a d i a n R e c o r d o f P e r f o r m a n c e p r o g r a m  c a t t l e i s r u n under t h e s u p e r v i s i o n o f A g r i c u l t u r e who r e q u i r e f o r i n c l u s i o n i n t h i s t e s t i n g p r o g r a m  f o r dairy Canada,  that a herd  h a s a minimum o f 15 cows o f one b r e e d , o f w h i c h a t l e a s t 10 m u s t b e r e g i s t e r e d . D a t a c o l l e c t e d d u r i n g t h e p e r i o d 1958 t o 1974 f o r m e d the  basis of this  study.  Cows f i r s t  t h r o u g h F e b r u a r y 1966 w e r e i n c l u d e d . lactation  start  recorded.  coded.  R e c o r d s w i t h age a t  These  l a c t a t i o n s s i n c e l a c t a t i o n number was  d a t a d i d n o t have r e a s o n s f o r d i s p o s a l  T h u s , cows s o l d f o r e x p o r t o r s o l d  c o u l d n o t be d i s t i n g u i s h e d If  1957  f r o m 18-36 m o n t h s w i t h no r e c o r d e d d r y p e r i o d ,  were c o n s i d e r e d as f i r s t not  c a l v e d d u r i n g September  f o rdairy  purpose  f r o m t h o s e removed f o r o t h e r r e a s o n s .  a cow's r e c o r d d i d n o t a p p e a r i n two c o n s e q u c i t v e y e a r s  subsequent t o h e r l a s t r e c o r d i n t h e h e r d where she s t a r t e d her of  first  r e c o r d , s h e was c o n s i d e r e d c u l l e d .  S i n c e about 25.8%  t h e cows l e a v i n g R.O.P. h e r d s a r e s o l d f o r d a i r y  (Burnside e t a l . ,  1971), t h e s i r e proof f o r l i f e t i m e  purposes production  and l o n g e v i t y w o u l d be b i a s e d downwards i f many d a u g h t e r s w e r e s o l d f o r t h e d a i r y purposes a f t e r completing the f i r s t  lactation.  - 27 -  In  o r d e r f o r a cow's r e c o r d o r r e c o r d s t o be i n c l u d e d i n  the study, the f o l l o w i n g c r i t e r i a 1)  Every  t e s t i n a herd having  h a d t o be  satisfied.  cow h a d t o h a v e a f i r s t  lactation  on  6 o r more l a c t a t i n g cows i n t h e y e a r  t h e h e r d s t a r t e d i n t h e t e s t i n g p r o g r a m . O n l y h e r d s on continuous  t e s t f o r a minimum o f t e n y e a r s w e r e i n c l u d e d .  2)  A l lfirst  l a c t a t i o n records should  have  s t a r t e d b e f o r e M a r c h 1966, t h u s a l l o w i n g e a c h cow t o c o m p l e t e 8 o r more y e a r s o f p r o d u c t i v e l i f e  by t h e e n d o f 1974.  The d a t a b a s e i n c l u d e d 141,231 l a c t a t i o n s  f r o m 51,599  cows i n 2090 h e r d s a c r o s s C a n a d a . A b o u t 7 1 % o f t h e s e h e r d s w e r e l o c a t e d i n O n t a r i o , 16% i n Quebec  and t h e r e s t i n o t h e r p r o v i n c e s .  Minimum l e v e l s o f a c c e p t a n c e o f r e c o r d s f o r i n c l u s i o n a n a l y s e s w e r e 300 d a y s f o r c a l v i n g i n t e r v a l , milk,  400 k g f o r f i r s t  lactation  culling.  clerical  10500 k g f o r f i r s t  lactation  lactation  2000 305-day  305-day f a t , 14000 k g f o r l a s t  305-day m i l k , 550 k g f o r l a s t l a c t a t i o n  190 months at  1600 k g f o r 305-day  40 k g f o r 305-day f a t , w h i l e t h e u p p e r l i m i t s w e r e  days f o r c a l v i n g i n t e r v a l , milk,  i n the  f o r length of productive l i f e  305-day f a t ,  and 215 months  These r e s t r i c t i o n s were n e c e s s a r y  f o r age  to eliminate  e r r o r s i n the records. L a c t a t i o n records less  than  183 d a y s i n l e n g t h c o u l d n o t be u s e d b e c a u s e t h e d a t a s e t d i d n o t have t h e 305-day l a c t a t i o n y i e l d s than  for lactations  shorter  183 d a y s , t h u s , r e c o r d s f r o m 183 d a y s t o 305 d a y s w e r e  c o n s i d e r e d a s 305-day l a c t a t i o n b u t no e x t e n s i o n s w e r e made for  records l e s s than a c t u a l  305-day  lactation.  - 28 -  Performance  Traits  A t o t a l o f f o u r t e e n t r a i t s , w h i c h measured lactation yield, considered included  l i f e t i m e production  and l o n g e v i t y were  i n this investigation. First  lactation  traits  3 05-day m i l k a n d f a t y i e l d s , a n d 305-day h e r d - y e a r  d e v i a t i o n m i l k and f a t y i e l d s . were l a s t  first  Lifetime production  l a c t a t i o n 305-day m i l k a n d f a t y i e l d s ,  lactation length, t o t a l  m e a s u r e d b y age a t c u l l i n g ,  life.  length of productive  number o f l a c t a t i o n s c o m p l e t e d . traits  last  1  l i f e t i m e m i l k a n d f a t p r o d u c t i o n , and  m i l k and f a t y i e l d s p e r d a y o f p r o d u c t i v e  used f o r these  traits  Longevity life  was  and t h e  D e f i n i t i o n s and n o t a t i o n s  are given  below.  M i l k 1 and M i l k L (kg)  : m i l k y i e l d s t o 305 d a y s i n t h e f i r s t  F a t 1 and F a t L (kg)  : f a t y i e l d s t o 305 d a y s i n t h e f i r s t . and l a s t l a c t a t i o n s , r e s p e c t i v e l y .  M i l k HY1 and F a t H Y l (kg)  : first  and  last  lactations, respectively.  lactation  yields,  305-day m i l k and f a t  r e s p e c t i v e l y , expressed  d e v i a t i o n s from t h e  as  corresponding  herd-year averages o f t h e herdmates. These d e v i a t i o n s were w e i g h t e d f o r t h e number o f h e r d m a t e s u s i n g t h e  - 29 -  weighting n•=  M i l k T and F a t T (kg)  factor  where  number o f h e r d m a t e s .  total  l i f e t i m e m i l k and f a t  production,  respectively,  t h o s e beyond  M i l k / D and F a t / D (kg)  = n/(n+l),  including  305 d a y s o f l a c t a t i o n s ,  m i l k and f a t p r o d u c e d p e r day o f productive  life,  respectively.  v a l u e s were o b t a i n e d d i v i d i n g  These total  l i f e t i m e m i l k and f a t p r o d u c t i o n s length  of produtive  life  as  by  defined  below.  LLL  (days)  Cullage  (months)  last  lactation  age a t d i s p o s a l . last  length.  Obtained  l a c t a t i o n length  adding  t o age a t  last  calving.  Plife  #  Lact  (months)  length  of productive  life  subtracting  age a t f i r s t  f r o m age a t  disposal.  number o f l a c t a t i o n o r c o m p l e t e d by a cow  obtained calving  lactations  before  disposal.  - 30 -  Statistical  Technique  The was  analytical  designed to account  variation After  as p o s s i b l e  Analyses  due  A basic  enable  included year, are  i n a model. age  potential  traits  were e s t i m a t e d .  The  d a y s open and affect  rationale  t h e models  analysis  mathematical  sources of v a r i a t i o n  at calving,  e x c l u d i n g them from  complete  P r e v i o u s r e s e a r c h has  above.  enumerated  the  to  should  indicated calving  is  model.  estimates of the e f f e c t s  sources which might  listed  discussed  and  and v a l i d  a l l significant  season,  of these t r a i t s  precept of accurate s t a t i s t i c a l  efficient  calculated,  environmental  parameters  the f o r m u l a t i o n of a p r e c i s e To  traits.  t o g e n e t i c c a u s e s was  f o r each  f o r environmental  sources of  study  sources of  f o r each of the performance  the v a r i a t i o n  g e n e t i c parameters  i n the present  f o r as many p o t e n t i a l  accounting f o r a l l possible  variations, and  t e c h n i q u e used  be  be  herd,  interval  performance  for including  them i n o r  f o r the p r e s e n t a n a l y s e s i s  below.  Herd  The to  f e e d i n g , management and  a herd w i l l  affect  p r o d u c t i o n and  breeding p o l i c i e s l o n g e v i t y of the  unique cows.  - 31 -  The h e r d e f f e c t w h i c h i s i n c l u d e d i n t h e m o d e l f o r e a c h a n a l y s i s , also includes the e f f e c t of l o c a t i o n i n respect of  climate.  Year  In  a herd the environmental e f f e c t ,  f e e d q u a l i t y and management p r a c t i c e s , may C u l l i n g i n t e n s i t y may  also d i f f e r  e.g.  climate,  v a r y between y e a r s .  from year t o year depending  on t h e h e a l t h s t a t u s o f t h e h e r d , m i l k and b e e f p r i c e s demand f o r b r e e d i n g s t o c k , w h i c h may e f f e c t was, of  vary with time.  and A year  t h e r e f o r e , i n c l u d e d i n t h e model f o r the a n a l y s e s  a l lthe traits..  Season  Season o f f i r s t  c a l v i n g was  c o n s i d e r e d i n t h e model  b e c a u s e cows o f a l l age g r o u p s i n t h e C a n a d i a n R e c o r d o f P e r f o r m a n c e h e r d s showed m o n t h l y v a r i a t i o n i n m i l k  yield,  summer c a l v i n g cows t e n d e d t o p r o d u c e l e s s m i l k t h a n w i n t e r c a l v i n g cows.  S u r v i v a l r a t e o f cows may  on s e a s o n o f c a l v i n g . the  Season o f f i r s t  also differ  calving also  depending influences  s u b s e q u e n t c a l v i n g s e a s o n s o f a cow d e p e n d i n g on t h e  average c a l v i n g i n t e r v a l i n the herd. m i l k y i e l d may  also d i f f e r  Selection pressure for  i n d i f f e r e n t seasons of  calving  d e p e n d i n g on t h e m i l k m a r k e t i n g s y s t e m and t h e number o f cows f r e s h e n i n g i n each season.  - 32  Age  at f i r s t  calving  Studies in age  the  first  fat yields  s u b s e q u e n t l a c t a t i o n s a r e a f f e c t e d by  c a l v i n g , w i t h a tendency of i n c r e a s e d  Since  v a r i a b l e age considered  h a v e i n d i c a t e d t h a t t h e m i l k and  and  at f i r s t  w i t h age.  -  data used i n t h i s study i n c l u d e d  at f i r s t  calving  production cows o f  (18 t o 36 m o n t h s ) , i t  n e c e s s a r y t o i n c l u d e age  m o d e l as a c o v a r i a b l e t o a d j u s t  at f i r s t  the  was  calving in  f o r i t s e f f e c t on  the  performance  traits.  Calving  i n t e r v a l and  d a y s open  Length of c a l v i n g i n t e r v a l i s mainly c o n t r o l l e d t h e number o f d a y s a cow Studies  r e m a i n s open a f t e r  parturition.  h a v e shown t h a t t h e number o f d a y s o p e n  a f f e c t m i l k y i e l d of the  current  and  the  significantly  following lactations.  Thus, t o a c c o u n t f o r d i f f e r e n c e s i n c a l v i n g i n t e r v a l , a v e r a g e and as  by  l a s t c a l v i n g i n t e r v a l s were i n c l u d e d  both  i n the  model  covariables.  I n t e r a c t i o n s among h e r d , y e a r and  Y e a r by  s e a s o n i n t e r a c t i o n was  m o d e l s i n c e i t was year to year.  season  thought seasonal  considered  in  the  e f f e c t might d i f f e r  I n t e r a c t i o n s o f h e r d w i t h y e a r and  season  from  - 33 -  c o u l d n o t be c o n s i d e r e d i n t h e m o d e l s f o r e n v i r o n m e n t a l e f f e c t s because  of computational l i m i t a t i o n s , since  number o f h e r d s w e r e u s e d .  large  H e r d , y e a r , s e a s o n , h e r d by y e a r ,  h e r d by s e a s o n and h e r d by y e a r by s e a s o n e f f e c t s w e r e removed f r o m t h e d a t a by c o n s i d e r i n g h e r d - y e a r - s e a s o n s u b c l a s s e s i n the  analyses f o r the estimation of genetic  parameters.  A n i m a l s s u b j e c t e d t o t h e common c a u s e s o f were grouped  together f o r a n a l y t i c a l purpose.  w e r e cows c u l l e d f r o m t h e h e r d a f t e r  first  variations  The  groups  lactation  (Group 1 ) , and cows w h i c h c o m p l e t e d more t h a n one  lactation  b e f o r e c u l l i n g (Group 2 ) .  analyzed  D a t a o f e a c h g r o u p was  u s i n g a s p e c i f i c l i n e a r model d e s i g n e d t o e s t i m a t e t h e e f f e c t s unique t o the group.  The  l i n e a r m o d e l f o r t h e G r o u p 1 cows  T h i s group  i n c l u d e d r e c o r d s o f 23018 cows w h i c h w e r e  c u l l e d f r o m t h e h e r d s f o r any r e a s o n a f t e r c o m p l e t i o n o f lactation.  L e a s t squares a n a l y s i s a f t e r Harvey  (1976)  u s e d t o e s t i m a t e t h e e f f e c t s o f h e r d , y e a r , s e a s o n and by s e a s o n i n t e r a c t i o n on t h e p e r f o r m a n c e m e a s u r e d p r o d u c t i o n and l o n g e v i t y .  Age  traits, at f i r s t  c o n s i d e r e d as a c o v a r i a b l e t o a d j u s t p e r f o r m a n c e d i f f e r e n c e s due was  as  follows:  to t h i s factor.  The  first  was year  which calving  was  traits for  l i n e a r m o d e l assumed  -  Y  i j k i  =  u  +  h  i  yj  +  +  k  s  ^  +  s  34  )  i k  -  +  b  A  i j k i  +  e  ijki  ( 1 )  where  Y . .. _ inki  = the observed value of v a r i o u s traits  of the l*"*  season o f t h e u  c  performance  cow f r e s h e n e d i n t h e k*"*  1  1  year i n the i*"*  1  herd.  = t h e o v e r a l l mean f o r t h e t r a i t when e q u a l f r e q u e n c i e s e x i s t i n a l l s u b c l a s s e s and A. , i s equal t o zero, ljkl ^  h. l  = the effect  of the i  y.3  = the effect of the j  s, k  = the e f f e c t of the k  t1*1  herd,  th  5  (ys)3  year of f i r s t t h  season o f f i r s t t h  = the j o i n t e f f e c t of the j  v  K  calving.  y e a r and k  calving. t h  s e a s o n when t h e e f f e c t o f y e a r a n d s e a s o n are b  held constant.  = r e g r e s s i o n o f t h e dependent v a r i a b l e Y ^ j ] ^ on t h e i n d e p e n d e n t  continuous  variable  A. ., , e a c h t i m e h o l d i n g t h e f i t t e d ljkl variables,  herd  (h.), year  A  ijkl  =  a  g  e  a  t  f:  "-  rst  calving  ( y . ) , season (s,) 3  l  and y e a r b y s e a s o n  discreate  (ySjjJ  K  constant.  f o r the corresponding  ljkl 'ijkl e.., n  th  , c.t _, t h1 = tcow h e random s o,kctiha t seeda swoint ho ft • h3e f r e s h e neefdf e xn ta hs e year J  c  t h  in the i  herd, which  i s assumed t o be  - 35  -  n o r m a l l y and  independently  distributed  w i t h a z e r o mean and  t h e same v a r i a n c e , 2 t h a t x s , e. ., a r e NID (0, (T ) . ljkl e n  All  effects  Year  i n t h e m o d e l e x c e p t e. ., , w e r e r e g a r d e d as ^ ljkl "  e f f e c t was  season  of f i r s t  the year of f i r s t calving  calving.  classifications,  There were  Season 1  A u g u s t ) and  Season 2  calving  l e s s t h a n o r e q u a l t o 36 m o n t h s was  age  age  at f i r s t  calving  (September t o F e b r u a r y ) .  and was  expressed  fixed. two  (March  to  A cow's c o n s i d e r e d as  i n months.  L i n e a r m o d e l f o r Group 2 cows  T h i s g r o u p i n c l u d e d r e c o r d s o f 28581 cows w h i c h f r e s h e n e d a t o r b e f o r e 36 m o n t h s o f age, one  more  than  l a c t a t i o n and w e r e c u l l e d f r o m t h e h e r d b e f o r e 1975.  m o d e l assumed was  Y  produced  first  i j k r  as  The  follows:  u + h. + y. + s  k  +  (ys)  j k  + bjA..^ + b B. 2  j k l  +  b C.  + e. ... ljkl where  Y. ., , ljkl  3  (2)  = the observed  value of a t r a i t of the  1^  t h cow f i r s t f r e s h e n e d i n t h e k •th . .th , , j year i n the I herd.  season  of  j k l  - 36 -  u  = o v e r a l l mean f o r a t r a i t when e q u a l f r e q u e n c i e s e x i s t i n a l l s u b c l a s s e s and A. ., , , B. , and C. ., T a r e e q u a l t o z e r o , ijkl i } k l ijkl ^ t h = the effect of the i herd.  h.  1  the e f f e c t o f the j s  t  the e f f e c t o f the k  k  h  year of f i r s t season  calving,  of f i r s t  calving. (ys) -v  the  =  j o i n t effect of the j  f c l 1  y e a r and k  s e a s o n when t h e e f f e c t o f y e a r and  t h  season  are held constant. ijkl  A  =  a  ^  e  in  a  ^^  t  freshening of the 1  r s t  t h animal  months. 4 - U  B. .. , ijkl  = average ^ in  C. , ijkl  calving interval of the 1 ^  animal  days.  = l a s t calving i n t e r v a l of the 1 ^  animal i n  days. b^,b  9  and b.j  = p a r t i a l r e g r e s s i o n c o e f f i c i e n t s of the dependent v a r i a b l e  (Y) on  continuous v a r i a b l e s  independent  (A,B and C) h o l d i n g  h . , y . , s . and ( y s ) . , c o n s t a n t , l j k ]k e  All  ijkl  effects  = random e r r o r ,  NID  2  (0, ^ j - ).  i n t h e m o d e l e x c e p t e. ., , w e r e c o n s i d e r e d f i x e d . ijkl c  C a l v i n g i n t e r v a l was d e f i n e d a s t h e number o f d a y s b e t w e e n two  consecutive calvings.  Due t o t h e e x c l u s i o n o f  l a c t a t i o n r e c o r d s s h o r t e r t h a n 18 3 d a y s , i n t e r v a l w o u l d be b i a s e d s l i g h t l y u p w a r d . and  last calving  the calving Both  average  i n t e r v a l s were used a s c o v a r i a b l e s i n t h e  - 37  model. In cases average was  and  o f cows c u l l e d  last  a n a l y z e d by To  necessary group.  calving  technique  and  equations  for  a l l other fixed  effects  y s , A)  s, y s , A)  indicate  fitting  effects  t e c h n i q u e was possible suspected  into u.  the  each  An  least  large herd  equations  additional  +  (ys) jk  1  + bA., . + e., , jkl jkl  of squares  run  the d i f f e r e n c e  R  (u, h, y,  (u, h, y, y s , A)  i n c l u d e d i n the parentheses.  a l s o used  f o r Group 2. f o r herd  and  interaction each  between h e r d  herd  A  R  s,  to  similar not i t was  year might  f o r a minimum o f t e n y e a r s  estimates of g e n e t i c parameters  A)  (u, y,  due  moreover,  and  effects,  s, y s ,  T h u s , i t was  effects,  (3)  f o r herd  T h e r e f o r e , i n s t e a d o f a d j u s t i n g f o r y e a r and  effects,  a  s o r t e d by  t h e r e d u c t i o n i n sums o f s q u a r e s  s i n c e r e c o r d s from used.  + s. k  where R  to a d j u s t data that  d a t a was  other than  to  too l a r g e to f i t  main e f f e c t w i t h  The  t o o b t a i n t h e sum  d e r i v e d from  (u, y,  i t was  model  1  - R  model  The  computer p r o g r a m s a v a i l a b l e ,  employed.  Y.. . = u + y. jkl 3  necessary  same.  groups,  (2014) was  f o r u + h^ were a b s o r b e d  the reduced  both  o r more c o v a r i a b l e s u n i q u e  f o r a b s o r b i n g one  number o f l e v e l s was  lactation,  f o r Group 1 cows.  combine t h e d a t a o f t h e two  t o a d j u s t f o r one  w h i c h was  second  i n t e r v a l s were t h e  S i n c e t h e number o f h e r d s  square  was  after  t h e same method as u s e d  constants using e x i s t i n g  using  -  exist, were  season  were o b t a i n e d  on  -  38  -  w i t h i n herd-year-season basis using data adjusted f o r age a t f i r s t  c a l v i n g and c a l v i n g  interval.  Adjustment of Data  B e f o r e c o m b i n i n g t h e d a t a f r o m two g r o u p s f o r g e n e t i c parameter a n a l y s i s , t h e o b s e r v a t i o n s were a d j u s t e d f o r appropriate covariables using regression technique.  For  Group 1, e a c h o b s e r v a t i o n o n e a c h o f t h e p e r f o r m a n c e  traits  was c o r r e c t e d  model:  Y  i =  f o r age a t c a l v i n g u s i n g t h e f o l l o w i n g  Y  (4)  i ~ < i " ) b  x  x  where  = estimated v a l u e of the performance for Y^  cow.  = observed v a l u e of the performance t r a i t f o r the  X^  the i  trait  i*"*  1  cow.  = age a t f i r s t  c a l v i n g i n months  f o r the  . th 1  cow.  X  = t h e a v e r a g e age a t f i r s t  calving.  b  = r e g r e s s i o n c o e f f i c i e n t f o r the independent v a r i a b l e X, o b t a i n e d f r o m t h e a n a l y s i s o f the  model 1 and p r e s e n t e d i n T a b l e  9.  f o r Group 2 were  O b s e r v a t i o n s o f each t r a i t f o r age a t f i r s t  c a l v i n g , average c a l v i n g  calving  using the following  interval  Y. = Y. -  b  l  (X  1  ±  - X ) x  - b (X . 2  2  - X ) 2  corrected  i n t e r v a l and  regression  - b (X . 3  3  last  model:  (5)  - X> 3  where  Y^  = estimated value of performance t r a i t f o r the  Y^  i*"*  cow.  1  = observed value o f performance t r a i t  f o r the  . th cow.  1  th X^  = age i n month o f t h e i  y^2±  =  average c a l v i n g  cow a t f i r s t  interval  calving,  i n days o f the  . th 1  cow. th  X^^  = last calving cow.  X^,x"  b^,b  3  X^, X  2  and  3  c o e f f i c i e n t s f o r the  independent v a r i a b l e s from the a n a l y s i s in Table  X^, X  that  of significance.  an i n s i g n i f i c a n t  2  and X , 3  obtained  o f t h e m o d e l 2 and p r e s e n t e d  9.  The raw d a t a was a d j u s t e d f o r a p p r o p r i a t e regardless  variables  X^.  = p a r t i a l regression  2  and b  i n days o f t h e i  = mean v a l u e s o f t h e i n d e p e n d e n t  2  and X  interval  covariable(s),  T h i s was done due t o  correction  term would n e i t h e r  data s i g n i f i c a n t l y nor introduce bias.  In t h i s  a d j u s t m e n t was f o r age a t f i r s t  only,  calving  recognition a l t e r the  s t u d y age  and t h e c a l v i n g  - 40  i n t e r v a l adjustments  -  were, i n f a c t , adjustments  f o r days open,  s i n c e the v a r i a t i o n i n g e s t a t i o n l e n g t h w i t h i n a breed  is  negligible.  Analyses  f o r E s t i m a t i o n of Genetic  Genetic parameters d a t a o f G r o u p s 1 and component  of  were e s t i m a t e d u s i n g c o r r e c t e d  2 c o m b i n e d and G r o u p 2 s e p a r a t e l y . The  v a r i a n c e was  the present study.  Parameters  The  the s u b j e c t of prime i n t e r e s t i n  restrictions  i m p o s e d on a c c e p t i n g a  s i r e w e r e b a s e d on c o n s i d e r a t i o n o f t h e r e l i a b i l i t y estimates of g e n e t i c parameters  produced.  in unacceptably estimates.  h i g h s t a n d a r d e r r o r s and  are minimized  40 a n i m a l s .  On  (1959)  from s i b a n a l y s i s ,  thus  the standard e r r o r s of  when s i b g r o u p s i z e i s b e t w e e n  f r o m t h e s i r e s h a v i n g l a r g e number o f d a u g h t e r s  records  distributed  For  combined  G r o u p 1 and  2 a n a l y s i s , a t o t a l o f 30,738 cows w i t h  s i r e s which  c a l v e d f o r the f i r s t time between September 1966  number o f cows.  The  cows.  10  s u b c l a s s e s were used f o r t h e  e s t i m a t i o n o f s i r e component o f v a r i a t i o n .  through February  result  unreliable  t h i s b a s i s i n each case h a l f - s i b  i n many h e r d - y e a r - s e a s o n  the  10 i n d i v i d u a l s p e r g r o u p ) w i l l  According to Robertson,  heritabilities and  ('<  of  Robertson  s t a t e d t h a t when e s t i m a t i n g h e r i t a b i l - i t i e s s m a l l s i b group s i z e  sire  were o b t a i n e d from  51,599  1957  original  Group 2 a n a l y s i s used d a t a from  T h e s e s u b s e t s o f d a t a r e p r e s e n t e d 138  identifiable  sires.  22,392 The  - 41 -  following  r e s t r i c t i o n s were imposed  t o i s o l a t e t h e new  data-  s e t s from the b u l k of the data base. 1)  Cows w h i c h w e r e m i l k e d f o r a minimum o f 18 3 days.  2)  Age  at f i r s t  calving  was  b e t w e e n 18 and  36  months. 3)  O n l y s i r e s w i t h 30 o r more d a u g h t e r s distributed trictions  i n 5 o r more h e r d s . T h e s e  lead to inclusion  of s i r e s  minimum o f 3 2 d a u g h t e r s d i s t r i b u t e d minimum o f 23 h e r d - y e a r - s e a s o n 4)  reswith  in a  subclasses.  O n l y h e r d s w i t h 4 o r more d a u g h t e r s r e p r e s e n t i n g a minimum o f 2 s i r e s w e r e  These r e s t r i c t i o n s were imposed  to l i m i t records to  s i r e s w i d e l y and e x t e n s i v e l y u s e d i n A r t i f i c i a l and t o e l i m i n a t e c o n f o u n d i n g w i t h h e r d a n d / o r A t o t a l o f 8187  herd-year-seasons  8 y e a r s and 2 seasons were formed  (HYS)  included.  Insemination  season  effects.  r e p r e s e n t i n g 1498  f o r t h e combined  set of data.  The G r o u p 2 d a t a h a d 7639 h e r d - y e a r - s e a s o n s u b c l a s s e s . h e r d - y e a r - s e a s o n was  herds,  A  d e f i n e d as a y e a r o r season w i t h i n a h e r d ,  t h i s means t h a t two cows f r e s h e n i n g i n d i f f e r e n t y e a r s  and/or  s e a s o n s i n t h e same h e r d w e r e c l a s s i f i e d i n t o d i f f e r e n t  HYS;  a l s o two cows f r e s h e n i n g i n t h e same y e a r a n d / o r  but  in  different Sires  h e r d s were s e p a r a t e d i n t o d i f f e r e n t  season HYS.  were grouped a c c o r d i n g t o t h e y e a r o f b i r t h .  Each group r e p r e s e n t s a s e t o f s i r e s b o r n d u r i n g a t h r e e - y e a r p e r i o d and e n t e r i n g s e r v i c e a p p r o x i m a t e l y d u r i n g t h e same p e r i o d of time.  F o r example,  s i r e Group 1 i n c l u d e d a l l s i r e s  - 42  born  d u r i n g p e r i o d 1946  through  1948  and w h i c h  probably  their  first  Table  10 shows t h e c o m p l e t e c l a s s i f i c a t i o n o f t h e  grouping. grouping  daughters  -  had  c a l v e d about f i v e years t h e r e a f t e r .  This grouping  s t r a t e g y was  sire  p r e f e r r e d over  on t h e b a s i s o f t h e y e a r o f s i r e ' s  first  daughter's  appearance i n the d a t a , because i n t h i s data s e t about  50%  o f t h e s i r e s had  (1958)  and  a daughter's  r e c o r d i n the f i r s t  a l s o t h e d i s t r i b u t i o n o f s i r e s by y e a r o f f i r s t  r e c o r d w e r e v e r y u n e q u a l w i t h 63 s i r e s 1959,  24  5 sires  sires  i n 1960,  i n 1963, The  distributed  11 s i r e s  6 sires  in  i n 1958,  i n 1961,  daughter's  20 s i r e s  9 sires  in  in  1962,  1964.  f o r s i r e grouping  was  to define populations  means a r o u n d w h i c h s i r e g e n e t i c v a l u e s  ( S c h a e f f e r e t a l . , 1975). Year grouping  s i n c e i t was presented  and  reason  with different  born  year  was  are used  a s s u m e d t h a t t h e s i r e s b o r n d u r i n g 1958-60 r e -  a more r e c e n t p o p u l a t i o n o f z y g o t e s  compared t o  those  d u r i n g 1946-48, though t h e l a t e r r e p r e s e n t a s e l e c t e d  group o f s i r e s , s i n c e they were i n s e r v i c e l o n g b e f o r e p e r i o d of data c o l l e c t i o n .  S i n c e g e n e t i c t r e n d has  the  been upward  i n m i l k p r o d u c t i o n i n H o l s t e i n s , the average g e n e t i c m e r i t  of  s i r e s b o r n d u r i n g 1958  that  of s i r e s born  through  d u r i n g 1946  (1975) s i r e g r o u p i n g  1960  through  s h o u l d be g r e a t e r t h a n  1948.  i s a l s o necessary  According  t o Henderson  f o r removing  bias,  because the estimated g e n e t i c v a l u e s of s i r e s t h a t continue i n s e r v i c e over  a long p e r i o d of time a f t e r being r e t u r n e d t o s e r v i c e ,  g e n e r a l l y tended t o d e c l i n e r e l a t i v e t o o t h e r b u l l s ; a l s o s i r e s of l a t e r g e n e r a t i o n s a p p e a r e d t o be u n d e r - e v a l u a t e d r e l a t i v e t o o l d e r s i r e s .  -  43  -  E s t i m a t i o n o f t h e s i r e component o f v a r i a t i o n  was  based on a m i x e d model w i t h h e r d - y e a r - s e a s o n and g e n e t i c group as f i x e d e f f e c t s random e f f e c t . fixed values  and s i r e w i t h i n g e n e t i c group as a  Herd-year-season e f f e c t s  were t r e a t e d as  t o a v o i d b i a s d u e t o d i f f e r e n c e s among s i r e s " i n a v e r a g e o f HYS w i t h w h i c h t h e y  are associated.  The l i n e a r  m i x e d m o d e l assumed w a s :  (6)  Y. _ = u + HYS. + G . + S . . + e . . ijkl 1 j ;jk ijkl 1 1  where Y. ., ,  = observation 1^  o f t h e p e r f o r m a n c e t r a i t on t h e  d a u g h t e r o f t h e k^"* s i r e w i t h i n t h e j"*"* 1  g e n e t i c group and f i r s t I  freshened  1  i n the  herd-year-season,  u  = t h e p o p u l a t i o n mean.  HYS^  = t h e e f f e c t due t o t h e i  t h of f i r s t  calving,  herd-year-season  considered  fixed  a n d common  t h to G. 3  a l l records  = a constant  i n the i  HYS.  common t o a l l r e c o r d s o f t h  daughters o f s i r e s i n t h e j group, considered S.,  as f i x e d .  = a random s i r e e f f e c t t h e k*"* i 1  s  r e  distributed  genetic  common t o d a u g h t e r s o f  within the  group  independently  w i t h mean z e r o a n d common 2  variance  (Ts .  The b r e e d i n g  values  of sires  -  44  -  i n t h e same g r o u p a r e r e g a r d e d a s a random s a m p l e f r o m t h e same p o p u l a t i o n . ijkl  e  t h e random e r r o r a s s o c i a t e d w i t h t h e r e c o r d of the 1  daughter o f the k  1  sire  within  th the j i  group and f i r s t  freshened i n the  herd-year-season independently  d i s t r i b u t e d w i t h mean z e r o a n d common variance (X ^ • ^ e  S i n c e t h e number o f h e r d - y e a r - s e a s o n s fit  (8187) was t o o l a r g e t o  c o n s t a n t s , h e r d - y e a r - s e a s o n e f f e c t was a b s o r b e d a n d  e s t i m a t e s o f a l l o t h e r e f f e c t s i n t h e model were o b t a i n e d u s i n g l e a s t s q u a r e s method  (Harvey, 1968).  The d e s i g n o f  a n a l y s i s o f v a r i a n c e a n d e x p e c t e d mean s q u a r e s f o r t h e m o d e l is  shown  below:  Source of Variation  Sum of Squares  Mean Squares  Expected Mean Squares  Within herd-year-season (HYS)  Y Y - R (u, HYS)  Total Reduction  R(u, HYS, G, S) - R(u, HYS)  Genetic group (G)  S^z" ^  (adjusted for HYS)  MS  (Te  Sire (S)/G  BgZg^Bg (adjusted for HYS)  MS  Te  Remainder  Y Y - R (u, HYS, G, S)  MS e  «"e  X  1  X  g  g  2  + k^s  2  + kjCs  2  + k  2  2  3  9  Q  -  45  -  To o b t a i n sum o f s q u a r e s f o r t h e h e r d - y e a r - s e a s o n e f f e c t a n a d d i t i o n a l r u n was n e c e s s a r y u s i n g a r e d u c e d m o d e l f r o m w h i c h HYS was l e f t  out.  The r e d u c e d m o d e l assumed was:  Y., , = u + G. + S., + e., , jkl 3 3k j k l  (7)  The sum o f s q u a r e s f o r h e r d - y e a r - s e a s o n e f f e c t w e r e o b t a i n e d from t h e d i f f e r e n c e R  R  ( u , HYS, G, S) - R  ( u , HYS, G, S) and R  ( u , G, S) w h e r e  ( u , G, S) i n d i c a t e t h e r e d u c t i o n i n  sums o f s q u a r e s due t o f i t t i n g included i n the parentheses.  constants f o r the e f f e c t s Sum o f s q u a r e s f o r s i r e  w e r e o b t a i n e d by t h e d i r e c t m e t h o d , f i t t i n g sires.  S i r e and g e n e t i c g r o u p  effect  c o n s t a n t s f o r 13i  l e a s t squares c o n s t a n t s were  used t o e s t i m a t e b r e e d i n g v a l u e s o f s i r e s f o r performance traits. The s i r e the  analysis  o f v a r i a n c e o f f u l l model  „ ^  ( CTe =  S  w h i c h i s <j-  where  component o f v a r i a t i o n was e s t i m a t e d f r o m  2 S  k-^  :  MS  s  + k  2  n  CT  (6) a s  -<Te  follows:  2  —  (  - MS  8  )  e  k  = w e i g h t e d ' number o f d a u g h t e r s p e r s i r e .  The k-^ v a l u e was c a l c u l a t e d  u s i n g t h e m e t h o d shown by  ( 1 9 7 0 ) f o r m o d e l s h a v i n g one random n e s t e d f a c t o r  i n mixed  Harvey model.  -  1  s  -  p  .  \^  . b.  46  -  q .  .1  .  b.  J  where s  = t h e number o f g e n e t i c g r o u p - s i r e  p  = t h e number o f g e n e t i c  number o f s i r e s i n t h e i  genetic  group.  = the reduced s e t of s i r e ^ c o n s t a n t s i n the  X  genetic i  jj  z  groups. th  = the b.  subclasses.  group.  = the d i a g o n a l elements of s e c t i o n of Z m a t r i x . - the o f f - d i a g o n a l elements of s e c t i o n of Z matrix.  The g e n e t i c p a r a m e t e r s f o r d i f f e r e n t t r a i t s were c a l c u l a t e d as d e s c r i b e d  performance  below.  Estimation of h e r i t a b i l i t y  The h e r i t a b i l i t y was c a l c u l a t e d f r o m t h e p a t e r n a l h a l f - s i b c o r r e l a t i o n as:  2  h  4 =  4 ^ (T  . 2 ,  £  cr  2  (  1  where 2  h s\  (j*  = heritability  i n narrow  sense.  2  = sire  component o f v a r i a n c e , w h i c h i s t h e  c o v a r i a n c e between h a l f - s i b s  (COVHS).  0  )  - 47 -  ^  2  = component o f e r r o r v a r i a n c e , w h i c h c o n s i s t s  e  2  of t o t a l  The c o v HS = h V  A  + 1/16  variance  ( ( T ) - COVHS. T  + 1/64  +  C*^ a f t e r r e m o v i n g h e r d - y e a r - s e a s o n  Thus,  and g e n e t i c group  e f f e c t s estimates a l l of the environmental  variance plus the  r e m a i n d e r o f t h e a d d i t i v e and n o n - a d d i t i v e g e n e t i c v a r i a n c e . Hence 4 t i m e s  ^  t h e <T"  2  ( a d d i t i v e v a r i a n c e ) d i v i d e d by  s +  (phenotypic variance) i s h e r i t a b i l i t y  i n narrow  sense ( h ) . 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 o b t a i n e d by m o d i f y i n g  estimate  was  t h e method o f S w i g e r e t a l . (196 4 ) .  Assuming n o r m a l i t y o f the i n t r a c l a s s c o r r e l a t i o n standard e r r o r of h e r i t a b i l i t y  [ S.E.  k 2 x  ( t ) , the  (h ) ] i s : 2  (N-S)(S-1)  where = intra  class correlation calculated 2 ,. ^ 2  as  ^2.  N  = total  number o f o b s e r v a t i o n s .  N-l  = N - (degrees  N-S  = degrees of freedom f o r remainder.  S-1  = degrees o f freedom f o r s i r e s w i t h i n genetic  o f freedom f o r f i x e d  groups.  effects)  k^  = weighted  number o f d a u g h t e r s  per  sire.  E s t i m a t i o n of g e n e t i c trend  One-half  of the s i r e ' s a d d i t i v e g e n e t i c value  was  A.  e s t i m a t e d by  G_. + S.^,  computed from t h e a n a l y s i s o f model  •~ . th 6, w h e r e G. i s t h e j l e a s t square g e n e t i c group constant ^ th and S j i s t h e l e a s t s q u a r e c o n s t a n t o f t h e k sire within k  the j * t  group.  1  f r o m one  The  change i n v a l u e o f s i r e c o n t r i b u t i o n s  y e a r t o t h e n e x t c a n be  assumed t o be e q u a l t o  c h a n g e i n v a l u e o f c o n t r i b u t i o n s due year  ( S c h a e f f e r e_t a l . , 1 9 7 5 ) .  t o dams f r o m y e a r  Under t h i s assumption  the to  the  change i n average g e n e t i c v a l u e s from y e a r t o y e a r  was  estimated  average  from t w i c e the average d i f f e r e n c e i n the  a d d i t i v e genetic values of s i r e s belonging to g e n e t i c groups.  Sum  of the a d d i t i v e g e n e t i c values of  w i t h i n a g e n e t i c g r o u p was  5KG.  where N S  > k  +  s  j k  )  =  obtained  N  K  G. +  sires  as:  Z  s  j k  i s t h e number o f s i r e s i n t h e j " * 1  K  different  1  group.  Since  = 0, t h e a v e r a g e a d d i t i v e g e n e t i c v a l u e o f s i r e s  t h e j t h g r o u p was  g i v e n by N,  ^G./N  ^ = G..  Thus, the  d i f f e r e n c e between t h e g e n e t i c group l e a s t squares d i v i d e d by  average  constants  3 gave h a l f the y e a r l y g e n e t i c change, s i n c e  each g e n e t i c group i n c l u d e d a t h r e e - y e a r p e r i o d .  in  - 49 -  Estimation of genetic  correlation  G e n e t i c c o r r e l a t i o n was o b t a i n e d d i r e c t l y output o f l e a s t squares  analysis  was c o m p u t e d by d i v i d i n g  (Harvey,  "family"  covariance  e s t i m a t e f o r two t r a i t s b y t h e g e o m e t r i c "family"  v a r i a n c e components. — 2  correlation analysis, Thus, t h e f o r m u l a  Q~  1968).  Correlation  component  mean o f t h e two  In paternal  half s i b  i s the "family"  c  from t h e  v a r i a n c e component.  f o rgenetic correlation  (  r , .) c a n g(x,y)'  y  be r e p r e s e n t e d a s :  /  r  \  /  =  ~  J  •s 2 (p~ ^  where  g  2  A  and  (J~ ^ g  X a n d Y, r e s p e c t i v e l y  and  c o v a r i a n c e b e t w e e n x a n d y. arrived  a t by t h e e x p r e s s i o n  2^s(x,y) where  s-  and ^ s ( x , y ) 2  (12)  Cls(Y)  are the sire Q~ ( s  x  y) ^  s  ^  components f o r t r a i t s e  s  -"-  The c o v a r i a n c e  re  [  component o f  CTs(x y) ]  w  a  s  — 2 s~ 2 ^ 2 (J~ (x+y) = (J <-(x) + ( J (Y) +  = [ 0"* (x+y)  (]~ (x+y) i s t h e s i r e s  =—  0  S(X)  Q  -  <Tg  ( x )  -  CTgWJ  1  / 2  '  component o f t h e sum o f t r a i t s  x a n d y. Standard the output modifying  errors  of genetic correlations  o f l e a s t squares  analysis,  t h e f o r m u l a g i v e n by T a l l i s  represented below.  Var  > (rg)  was c a l c u l a t e d  as  by  (1959) w h i c h i s  The v a r i a n c e o f g e n e t i c  c a n be w r i t t e n  obtained  correlation  from  - 50 -  V a r  (1+r ) d + r ) d + t k - l ) ^ ) ( l + ( k - l ) t ) 2  (9g)  2  2  d )c t , t _ s 12 - 2r r  f a  [ t t ( l + ( k - l ) t ) (l+(k-l)t ) ] 1  2  1  l+(k-l)t, i —  l+(k-l)t~ _ £.  +  r (t,-t ) 2 ± f— t 2  +  2  2  2  t  l  (1+r )(1+r )(l-t )(1-t ) g w 1 ^ 2  n  d.k't,t l 12  2  0  1  _  t  - 2r r [ t..t,(l-t,) d - t ) ] q w 1 2 1 ^ L  D  b  where  V 12  i ' 2  t  t  d  r  2 L  V  n  t  r  a  w  c  J  -  a  s  s  11 22 V  c o r r e l a t i o n s f o r two t r a i t s .  = degrees of freedom f o r s i r e within  g  'q'*!'^'  v 12 V  11 22 i  =  1 _ t +  are given by:  W  =  V  l  2  Estimates of r. and r  r  2  genetic  group. d^  = degrees of freedom f o r remainder.  k  = weighted number of daughters per s i r e .  V^ »v^ 2  = are covariances between and within s i r e s ,  2  respectively. V  ^ l / 2 2 ' l l ' 1 2 = are mean squares between and V  V  V  within  s i r e s , respectively.  2  - 51 -  Standard e r r o r  of g e n e t i c c o r r e l a t i o n  (S.E.  r ) was  derived  y  f r o m S.E.  -  = 4  / /  g  Var ^  }  ( 1 3 )  g  E s t i m a t i o n o f p h e n o t y p i c and e n v i r o n m e n t a l  correlations  P h e n o t y p i c and e n v i r o n m e n t a l c o r r e l a t i o n s w e r e o b t a i n e d from the output of the l e a s t squares These parameters  w e r e e s t i m a t e d as  CT (x,y)  e  P  ( x  '  Y )  .  1^2  =  j[3"e(x)  s  ,2 <Ts(x)]  +  analysis.  follows:  CT (x,y) + r  also  [(fe(y)  , +  (14) » 2  8*s(y)]  (T (x,y) - 3 (T (x,y) e  r  E(x,y)  -  - /j_  "„  -~ 2  J[<T (x) " e  Where  r  , . and p(x,y)  s  3  77^2 CTs(x)][<re(y) ^^ ~ 22  r„, . represent phenotypic E(x,y) f if r  ,  "  3  „/s,2 A 2 CT (y)] s  and  (T . . ^ e(x,y) components o f c o v a r i a n c e  e n v i r o n m e n t a l c o r r e l a t i o n s b e t w e e n t r a i t s x and y; CV . . are the e r r o r ^ s(x,y)  and  and  sire  b e t w e e n t r a i t s x and y, r e s p e c t i v e l y ; * 1  ^  2  (V , . U s (y)  and  ^  (T  f o r t r a i t s x and  1  (15)  and  ^  2  (T , \ r s(x)  V J  ^  2  C\ , \r ^Je(x)  2  , , a r e s i r e and e r r o r v a r i a n c e c o m p o n e n t s e (y) y.  In a l l the e s t i m a t e s of g e n e t i c parameters  i t was  assumed t h a t t h e r e i s no i n t e r a c t i o n o f s i r e w i t h h e r d - y e a r season e f f e c t s .  Estimation of breeding value  In s e x - l i m i t e d t r a i t s breeding values of s i r e s are b a s e d on t h e p e r f o r m a n c e  of t h e i r daughters.  I f the records  o f t h e d a u g h t e r s o f s i r e a r e made on a c o m p a r a b l e b a s i s , t h e g e n e t i c c o v a r i a n c e between daughters  ( (J~ , 1  ) i s primarily 2  2  a function of the additive genetic variance because t h e s i r e e f f e c t to a daughter  (  i s the only genetic e f f e c t  (d^) o f a s i r e a n d a n o t h e r d a u g h t e r  t h e same s i r e .  common (d,,) o f  A s s u m i n g t h e p o p u l a t i o n i s m a t i n g a t random,  and o n l y t h e a d d i t i v e g e n e t i c v a r i a n c e i s p r e s e n t i n t h e s i r e component, t h e n , t h e s i r e v a r i a n c e i s e q u a l t o t h e c o v a r i a n c e (J  2  = (J~, . The v a r i a n c e s a a o f s i r e d a u g h t e r a v e r a g e c a n be shown e q u a l t o ( G a c u l a e t a l . , 1968):  of t h e s i r e ' s daughters i . e .  1  2  2  2 *J  where  CT ^r ^ d 2  <T HYS m m 2  d  , /r2 s  x  +  CT e n  i s t h e variance of a s i r e daughter  average,  a s s u m i n g one r e c o r d p e r d a u g h t e r a n d t h e r e a r e m h e r d - y e a r seasons and n d a u g h t e r s . season e f f e c t s ,  Adjusting records f o r herd-year-  2  <J" -r d reduces t o : 2  (j-^— = S_- a n d e k  i  a r e  0" g  +  —  —  w i t h the assumption  independently distributed.  that  The r e g r e s s i o n  o f f u t u r e d a u g h t e r s on p r e s e n t d a u g h t e r s c a n be e x p r e s s e d i n terms o f n daughters by:  -  _  b  53  -  CTs  ^ ^ 2  CT d  d n d  2  ^2  +  s  u  n  jvL  n  Q-2  n +  S—  A s s u m i n g s i r e ' s m a t e s a r e random s a m p l e s o f t h e p o p u l a t i o n , t h e g e n e t i c m e r i t o f a s i r e i s e q u a l t o 2 (G.. + S_.j_) , w h e r e G_. a n d S^, a r e t h e l e a s t s q u a r e s e s t i m a t e s o f t h e g e n e t i c group and t h e s i r e w i t h i n Therefore, the expected  g e n e t i c group e f f e c t s ,  breeding value  respectively.  (EBV) o f a s i r e c a n be  estimated as:  EBV = b  dnd  2n  (G. + S. )  -  K  n  To s t u d y t h e r e l a t i o n s h i p s  +  2  (G\ + S ) (16) j k  -~ 2  (T  o f EBV o f s i r e f o r f i r s t  l a c t a t i o n y i e l d s w i t h EBV f o r l i f e t i m e , p r o d u c t i o n and longevity,  p r o d u c t - m o m e n t c o r r e l a t i o n and s t e p w i s e r e g r e s s i o n  t e c h n i q u e w e r e e m p l o y e d u s i n g TRP p r o g r a m (1977) a v a i l a b l e at the U n i v e r s i t y  o f B.C. C o m p u t i n g C e n t r e .  e q u a t i o n s were f i t t e d longevity.  Prediction  t o EBV f o r l i f e t i m e p r o d u c t i o n a n d  -  54  -  RESULTS AND  Means and  V a r i a t i o n s of  The variation first  Traits  means, s t a n d a r d  of t r a i t s ,  calving  DISCUSSION  d e v i a t i o n s and  c a l c u l a t e d w i t h i n herd-year-season  are given  i n Table  4.  t r a i t s were c o m p a r a b l e t o r e p o r t s by (Hargrove  e t aJL. , 1969;  Plowman, 1963; W h i t e and HY1 milk  and and  other  Kopland,  N i c h o l s , 1965;  Gill  F a t H Y l were d e r i v e d by fat, respectively  1963;  and  d e v i a t i o n s were n e g a t i v e , the  coefficients  were a l i t t l e h i g h e r  than  a more r e s t r i c t e d  (Van V l e c k ,  1964;  1965).  data  The  restrictions, age  Miller  Allaire,  Since  first  Milk  lactation herd-year  most o f  the  n e g a t i v e means f o r  of t h i s  e t a l . , 1951;  The 2 9.3  a v e r a g e age + 2.9  measurements  W h i t e and  s t u d y were r e l a t i v e l y  Larson  at f i r s t  months.  f i n d i n g s o f H a r g r o v e e t a l . (1969),  free  from or a  the given  s i n c e a l l cows  their  calving  This value  Nichols,  lactations  e t a l . , 1951)  traits  s t u d i e s w h i c h have  of l i f e t i m e  as a g i v e n number o f  1964;  f o r performance  some o f t h e o t h e r  i n c l u d e d were assumed t o have c o m p l e t e d  the  1976).  lactations,  of v a r i a t i o n  definitions  Larson  such  (Van V l e c k ,  h e r d was  e t a l . , 1967;  d e v i a t i n g the  giving  and  traits. The  had  Gaalaas  from the c o r r e s p o n d i n g  thus,  of  researchers  Evans e t a l . , 1964;  Lamb and  of  Means f o r p r o d u c t i o n  average o f t h e herdmates i n d i f f e r e n t  both  coefficients  productive  calculated  within  i s i n agreement Gill  and  life.  Allaire  with  T a b l e 4.  Trait  M e a n s , s t a n d a r d d e v i a t i o n s ( S D ) , and c o e f f i c i e n t s o f v a r i a t i o n (CV) o f t r a i t s , u s i n g d a t a o f c o m b i n e d G r o u p s 1 & 2, c a l c u l a t e d w i t h i n herd-year-season of f i r s t c a l v i n g .  a  First  lactation  305-day m i l k y i e l d  First  l a c t a t i o n 305-day f a t y i e l d  First  l a c t a t i o n herd-year d e v i a t i o n milk  First  l a c t a t i o n h e r d - y e a r d e v i a t i o n f a t y i e l d ( F a t HY1)  Last lactation  305-day m i l k y i e l d  Last  305-day f a t y i e l d  lactation  Last l a c t a t i o n  ( F a t 1) y i e l d ( M i l k HY1)  ( M i l k L) ( F a t L)  l e n g t h (LLL)  Total lifetime milk yield  ( M i l k T)  Total lifetime  f a ty i e l d  Milk yield/Day  of productive  Fat yield/Day  ( M i l k 1)  ( F a t T)  of productive  Age a t d i s p o s a l  life life  (Milk/D) (Fat/D)  (Cullage)  Length of productive  life  (Plife)  Number o f l a c t a t i o n s (# L a c t ) a  Notations tables.  b  given  SD  4896  703  14. 4  183  26  14.2  -639  709  -24  27  5513  1149  20.8  207  45  21.7  342  71  20.8  20165  15628  77.5  761  592  77.8  15. 2  2  13.2  b  .57  . 08  14. 0  72  30  41.7  43  30  69.8  3.3  2.2  66.7  i n t h e p a r e n t h e s e s f o r t h e above t r a i t s w i l l  T r a i t s are defined  CV(%  Mean  be u s e d i n t h e s u b s e q u e n t  i n p a g e s 28 and 29.  U n i t s a r e k g , e x c e p t c u l l a g e a n d P l i f e w h i c h a r e i n m o n t h s , L L L i n d a y s a n d # L a c t i n number.  - 56 -  (1976) a n d L i n a n d A l l a i r e r e p o r t e d by o t h e r workers and K o p l a n d ,  196 3 ) .  (1978), b u t i s h i g h e r than (White and N i c h o l s ,  those  1 9 6 5 ; Lamb  T h i s i s p a r t l y due t o t h e u p p e r  limit i  of  36 months f o r age a t f i r s t  in  t h e p r e s e n t s t u d y , w h e r e a s t h e u p p e r l i m i t was 3 4 m o n t h s  in  d a t a o f White and N i c h o l s W i t h i n herd average  this  study  c a l v i n g p l a c e d on t h e d a t a  (1965). calving  interval obtained i n  (42 0 + 6 8 d a y s ) i s l o n g c o m p a r e d t o o t h e r s t u d i e s  (Everett e t a l . ,  1966/ M i l l e r e t a l . ,  1967).  A part of this  d i f f e r e n c e may b e due t o t h e v e r y h i g h u p p e r l i m i t interval  imposed i n t h i s s t u d y  upper l i m i t of  for calving  (2 0 00 d a y s ) c o m p a r e d t o t h e  (600 d a y s ) i m p o s e d b y M i l l e r  e t aJL.  ( 1 9 6 7 ) . Some  t h e r e g i s t e r e d herds of H o l s t e i n s i n c l u d e d i n t h i s  were o f h i g h p r o d u c t i o n l e v e l .  study  Farmers appear t o t o l e r a t e  longer c a l v i n g i n t e r v a l f o r high producers, which might for  a p a r t o f t h e longer average  calving  Environmental Parameters A f f e c t i n g P r o d u c t i o n and L o n g e v i t y  account  interval.  Lifetime  I t was n e c e s s a r y t o a c c o u n t  for identifiable  systematic e f f e c t s before subjecting the data t o analyses f o r the genetic parameters. year, season  To e s t i m a t e t h e e f f e c t s o f h e r d ,  and y e a r by season  interaction,  t h r e e c o v a r i a b l e s , t h e d a t a were c l a s s i f i e d  and e f f e c t s o f i n t o two g r o u p s .  Age  at f i r s t  c a l v i n g , o n e o f t h e c o v a r i a b l e s , was common t o  all  t r a i t s o f b o t h t h e Group 1 (cows c u l l e d a f t e r  first  - 57 -  lactation) than  and G r o u p 2 (cows c u l l e d a f t e r c o m p l e t i n g  one l a c t a t i o n ) .  calving interval only.  Average c a l v i n g i n t e r v a l  a n a l y s i s o f v a r i a n c e - c o v a r i a n c e were  used t o e s t i m a t e the e f f e c t s of these constants a s s o c i a t e d w i t h herd  factors.  s t u d y , and no s p e c i f i c  from t h i s  effect.  Least  e f f e c t c o u l d n o t be  e s t i m a t e d b e c a u s e o f l a r g e number o f h e r d s in this  last  w e r e common t o a l l t r a i t s o f t h e G r o u p 2  Least squares  squares  and  more  (2014) i n c l u d e d  i n f e r e n c e s w e r e t o be  drawn  The l e a s t s q u a r e c o n s t a n t s a s s o c i a t e d  w i t h 8 y e a r s and 2 s e a s o n s a l l o w e d d e t e c t i o n o f y e a r l y and seasonal trends i n production. l e a s t squares Tables  analyses  Summaries o f t h e r e s u l t s o f  f o r G r o u p 1 and G r o u p 2 a r e shown i n  5 and 6, r e s p e c t i v e l y .  T h e s e t a b l e s show t h e c o 2  efficient  of determination  (R ) f o r t h e t o t a l m o d e l , w h i c h i s  a measure o f t h e p o r t i o n o f t o t a l v a r i a b i l i t y accounted  for  by t h e e n v i r o n m e n t a l  e f f e c t s i n c l u d e d i n the model. For the 2 t r a i t s e x a m i n e d f o r G r o u p 1 cows, t h e t o t a l R r a n g e d f r o m 18.1% f o r l e n g t h o f p r o d u c t i v e l i f e ( P l i f e ) t o 7 6 . 2 % f o r age 2 a t d i s p o s a l ( C u l l a g e ) . F o r G r o u p 2, t o t a l R r a n g e d f r o m 2 12.5%  f o r # L a c t t o 4 3 . 3 % f o r F a t 1 and F a t / D .  values indicated the r e l a t i v e l y environmental  effects considered  small importance i n this  study  t h e t o t a l v a r i a b i l i t y o f t h e P l i f e and # L a c t . F a t 1, M i l k / D  These R  and F a t / D , h o w e v e r , t h e s e e f f e c t s  of the systematic,  i n determining F o r M i l k 1, determined  a l a r g e p o r t i o n (38.4% t o 43.3%) o f t h e t o t a l v a r i a b i l i t y . 2 The v e r y h i g h t o t a l R f o r c u l l a g e i n G r o u p 1 was due m a i n l y  Summary o f t h e a n a l y s i s o f v a r i a n c e - c o v a r i a n c e f o r environmental e f f e c t s : f o r Group 1.  Table 5 .  R Trait  Total C•S•S•  Milk 1  20.00xl0  9  2.86xl0  7  14.34xl0  9  2.04xl0  7  LLL  11.36xl0  Milk T Fat  Fat  1  M i l k HY1 Fat  HY1  T  2  Values ( % )  a  Total Fitted  Herd  Year  Season  Year x Season  Age a t 1st Calving  38.4  33.7  2.43  .89  .02°  2.13  40.1  35.3  2.63  .72  .02  c  2.42  19.6  15.4  0.13  .77  .02  c  3.00  21.0  16.4  0.19  .55  .01  c  3.43  7  18.2  17.4  0.29  .05  .11  0.06  44.32xl0  9  28.9  25.0  1.95  .44  .05  1.41  65.01xl0  7  29. 5  25.7  2.06  .34  .05  1.52  41.4  37.4  2.39  .54  .04  41.6  37.6  2.55  .38  .02  2.17  Milk/D  1.7xl0  Fat/D  2.53x10  Cullage  4.31xl0  5  76.2  5.0  0.08  .014  .03  47.30'  Plife  1.26xlO  D  18.1  17.3  0.28  .05  .11  0.06  D.F.  23017  2029  2013  1  7  a b  c d  5  .  7  2 A l l R v a l u e s s i g n i f i c a n t (P < . 05) u n l e s s otherwise s t a t e d . 2 P l i f e i n mo. T o t a l c o r r e c t e d sums o f squares (kg except c u l l a g e , Not s i g n i f i c a n t a t .05 l e v e l . T r a i t s a r e d e f i n e d i n pages 28, 29 and T a b l e 4.  2  c  and  2.32  •»  X  2 LLL days )  T a b l e 6.  Summary o f t h e a n a l y s i s o f v a r i a n c e - c o v a r i a n c e f o r e n v i r o n m e n t a l e f f e c t s : f o r G r o u p 2. R Values (%) 2  Total C•S•S• b  m  -4.  d  Trait  Milk 1  22.42xl0  9  3.27xl0  7  14.89xl0  9  2.16xl0  7  Fat 1 Milk  HY1  F a t HY1 Milk L  45.45xl0  9  7.01xl0  7  Fat L LLL  16.15xl0  Milk T  -71. 3 9 X 1 0  Fat T  10.33xl0  1 1  9  Calving Interval (Avg.)  Calving Interval (Last)  Season  Year x Season  Age a t First Calving  2. 80  1.08  .02  2. 63  0.44  0. 0 0  35.9  2.92  0.92  .01°  3.20  0.30  0.00  18. 0  11. 9  0.17  1.07  .02°  4.07  0. 60  0.00°  18. 9  12.4  0.28  0.84  .02°  4.97  0.42  0. 00°  29.7  26.3  0.82  0.01  .02°  0.05  0.02  0.73  30.0  26.0  0.89  o,oo  .01°  0.06  0. o o  0.07  0.03  .04°  0.01  Total fitted  Herd  Year  41. 9  34.4  43.3  12.8  7  a  9.5  C  c  C  c  0. o o  C  c  c  1. 07 1.00  0.40  1J.59  0.01°  0.38  1.66  .00°  0.46  2.24  0.11  13. 8  11.4  0.12  0.00°  .03°  o.oo  14. 0  11.6  0.12  0.00°  .03  43.3  35.8  2.17  0.20  C  c  Milk/D  1. 8 0 x l 0  Fat/D  2.89xl0  2  42.6  35.8  2. 36  0.12  .00°  0.54  1.97  0.15  Cullage  2.51xl0  7  15. 5  10. 3  0.19  0. 00°  .03  0.78  0.04  1.63  7  14. 0  10. 5  0.20  o.oo  .03°  0.01  C  0.04  1. 65  0.00  .03°  0. 02  1.18  1.26  5  Plife  2.47xl0  # Lact  1.2-OxIO'  12. 5  10. 6  0.20  D.F.  28580  1515  1497  7  5  c  C  1  a  A l l R  values are s i g n i f i c a n t  b  Total corrected  c d  N o t s i g n i f i c a n t a t .05 l e v e l . T r a i t s a r e d e f i n e d i n p a g e s 2 8, 2 9 a n d T a b l e 4.  7  C  1  1  (P < .05) u n l e s s o t h e r w i s e s t a t e d . 2 2 2 sums o f s q u a r e s (kg e x c e p t c u l l a g e , P l i f e i n mo. and L L L d a y s ) .  1  C  C  - 60  t o the  contribution  w o u l d be age  of  age  expected since  at f i r s t  calving  c a s e s w e r e 305  -  at f i r s t  calving  C u l l a g e was  and  (47.3%), which  o b t a i n e d by  l a c t a t i o n length,  summing  w h i c h i n most  days. 2  The  partial R  individual effects i n d i c a t i o n of in  the  the  model.  T,  (Table 5).  significant  an  separate  season  effects  interaction  Fat/D were s i g n i f i c a n t f o r  In Group 2 a l l e f f e c t s e x c e p t y e a r age  at  average c a l v i n g  last calving  and  the  model, w h i c h gave  e x c e p t y e a r by  lactation traits  Plife;  shown f o r  r e l a t i v e importance of the  season f o r a l l t r a i t s ; Fat  also  c o n s i d e r e d i n the  A l l effects  for a l l f i r s t Group 1  v a l u e s are  first  f o r LLL,  i n t e r v a l f o r Fat  interval for a l l f i r s t (Table 6).  calving  L,  Milk  LLL;  lactation traits  D i s c u s s i o n s on  o f v a r i a t i o n a f f e c t i n g p r o d u c t i o n and  by T,  and were  s i g n i f i c a n t sources longevity  are  now  presented. Herd  The in  in  s i g n i f i c a n t f o r a l l the  t h i s s t u d y , a c c o u n t i n g f o r b e t w e e n 5%  37.6% 9.5%  e f f e c t o f h e r d was  ( f o r Fat/D) of t o t a l v a r i a b i l i t y ( f o r LLL)  G r o u p 2.  and  35.9%  (for Fat  1)  management, c u l l i n g p r a c t i c e s w i t h each herd.  Individual  and  i n G r o u p 1 and  of  Herd e f f e c t r e f l e c t e d the  (for cullage)  the  total  e f f e c t s of  and between  variability nutrition,  microenvironment  e f f e c t of  traits  these factors  associated could  -  n o t be  determined  data  set.  milk  and  from  the  fat yields  and  effect  on  the  first  (33.7% t o 35.9%) a g r e e d  i n determining  Herd e f f e c t s  -  information available  Magnitude of herd  s t u d i e s which i n d i c a t e d factor  61  herd  the  as t h e  first  with  s i n g l e most  l a c t a t i o n milk  in  this  lactation earlier important  and  fat yields.  o f s i m i l a r m a g n i t u d e were a l s o o b s e r v e d  fat yields  p e r day  of l i f e  in this  study.  for milk  Lower  herd  2 R  values  Fat  1,  herd  f o r M i l k HY1  and  F a t HYl  show t h e e f f i c i e n c y  effects  from  the  of herd-year  lactation  total  l i f e t i m e p r o d u c t i o n and  lower  i n magnitude  p r o d u c t i o n p e r day  compared t o M i l k  Herd e f f e c t s  longevity traits  of p r o d u c t i v e  and  d e v i a t i o n s i n removing  records.  compared t o f i r s t  1  lactation  were  for  consistently  yields  and  standard errors  for  life.  Year  Year l e a s t p r o d u c t i o n and presented production through Fat  T,  least  squares  longevity t r a i t s  i n Appendix T a b l e s and  means and  1 and  squares  and  # Lact.  constants  therefore,  estimates  model.  are  Yearly trends i n 7.  i n M i l k 1, F a t  Figures  1  1, M i l k  T,  of  the  of each dependent v a r i a b l e a s s o c i a t e d  against year of f i r s t  the  Group 2  Graphs r e p r e s e n t p l o t t i n g  with years  in  2.  l o n g e v i t y are given i n Table  4 show t h e y e a r l y t r e n d s Plife  f o r Group 1 and  calving.  of year e f f e c t s  free  They from  are, other  effects  Table 7.  Average y e a r l y and seasonal trends i n production and longevity t r a i t s based on l e a s t squares constants obtained form analyses on models 1 and 2. Yearly Trends* ( F i r s t C a l v i n g P e r i o d 1958-65) 3  frait  3  • 'Group 1  Group 2  Seasonal Trends' (Season 2 - Season l ) 3  C  Group 1  c  Group 2  204  221  7  8  -16.07  160  179  -0.82  5  6  Milk 1  71  73  Fat 1  2.81  2.98  M i l k HY1  -12.40  F a t HY1  -0.67  63  Milk L  NA  Fat L  NA  2.61  LLL  1.83  1.00  Milk T  96  Fat T  3.83  Milk/D  NA  36  NA  1 2  -3  107  130  4.05  7  0.0  0.20  0.21  0.5  0.3  Fat/D  0.008  0.008  0.01  0.01  Cullage  0.052  -0.527  0.0  -0.4  Plife  0.061  -0.529  0.10  -0.4  # Lact  NA  -0.042  NA  78  0.0  a  T r a i t s are defined i n pages 28, 29 and Table 4.  b  U n i t s are kg, except Cullage, P l i f e which are i n months, LLL i n days and # Lact i n number.  c  Season 1 (March-August) , Season 2 (September-February) .  Year of f i r s t calving  Year of f i r s t calving  Year of f i r s t calving  Year of  f i r s t calving  - 67  -  There were i n c r e a s i n g t r e n d s m i l k and genetic  i n the  f a t y i e l d s o v e r t h e p e r i o d 1960 i m p r o v e m e n t and  practices. fat  y i e l d s w e r e 71 kg  and  73 k g  and  2.98  i n c r e a s e s i n m i l k and w e l l w i t h i n the  and  kg,  t o 1965,  better nutrition  Y e a r l y i n c r e a s e s i n the 2.81  kg,  first  and  first  lactation due  management  lactation milk  and  r e s p e c t i v e l y f o r Group  r e s p e c t i v e l y f o r G r o u p 2. f a t y i e l d s obtained  range of those  to both  showed h i g h e r a n n u a l i n c r e a s e i n t h e  Yearly  in this  reported.  study  are  H o w e v e r , some s t u d i e s  first  lactation  f r o m 90 kg t o 128  kg  1972).  L i f e t i m e m i l k and  f a t y i e l d s have a l s o i n c r e a s e d  of p r o d u c t i v e d e c r e a s e d by  life .53  t h e G r o u p 2 cows  4 kg,  and  Verde et a l . ,  r e s p e c t i v e l y , whereas, the  t h e number o f l a c t a t i o n  month and (Table  ( G a c u l a e t a l . , 1968;  milk  ranging  t h e r a t e o f 78 k g and  .04  1;  lactation,  at  length  completed  respectively in  7).  Season  Though s e a s o n o f f i r s t source for  of v a r i a t i o n  c a l v i n g was  f o r a l l the t r a i t s  a  i n G r o u p 1,  l e s s t h a n 1% o f t h e t o t a l v a r i a t i o n o f any  study. first  I n G r o u p 2,  and  production  affect significantly  per the  l o n g e v i t y i n cows w h i c h s u r v i v e d c u l l i n g Season l e a s t  i t accounted  trait  under  season a f f e c t e d s i g n i f i c a n t l y o n l y  lactation traits  c a l v i n g d i d not  significant  s q u a r e s means and  standard  day.  the  Season of  first  lifetime production after first  and  lactation.  e r r o r s are presented  in  -  Appendix Table first  -  seasonal trends  f r e s h e n i n g i n season  more m i l k and first  3 and  68  different  no  i n season  1  7.  Cows  (September t o F e b r u a r y )  f a t i n the f i r s t  freshened  practically  2  i n Table  lactation  compared t o  (March - A u g u s t ) .  d i f f e r e n c e between t h e cows f r e s h e n i n g i n  seasons  i n terms o f C u l l a g e , P l i f e  n e g a t i v e t r e n d i n C u l l a g e and this  study  those  T h e r e were  i n Group 1  # L a c t i n Group 2, w h e r e a s Group 2 cows showed a  in  produced  agreed  Plife.  i n nature with  North  E a s t U n i t e d S t a t e s and  Canada  1974;  Wunder and  1967;  McGilliard,  Adjustment f o r season  e f f e c t was  Seasonal  and  slight  trend  obtained  studies reported (Ahunu, 1978; Miller  two  from  Mao  et a l . ,  e t a l . , 1970).  warranted  i n view of  the  s e a s o n a l c h a n g e s i n many a s p e c t s o f t h e cow's e n v i r o n m e n t . Included to  i n these  s t o r e d f e e d , a management s y s t e m s t i l l  farms, round  while other  season  utilized  pasture  p r e s e n t on many  s t o r e d f e e d s on  a  year-  interaction  Y e a r by T,  farmers  change from  basis.  Y e a r by  Fat  s e a s o n a l c h a n g e s were t h e  Milk/D,  accounting variation  season  LLL,  C u l l a g e and  f o r a very i n these  differences  i n t e r a c t i o n was  small fraction  traits,  i n these  Plife  traits  significant  o n l y i n Group (^  .1%)  which i n d i c a t e d were n o t  of the  t h a t the  c o n s i s t e n t over  for Milk 1, total seasonal the  R e l a t i o n s h i p s o f Age a t F i r s t C a l v i n g w i t h P r o d u c t i o n and L o n g e v i t y  Age  at f i r s t  c a l v i n g was  a significant  T,  source  of  years.  -  v a r i a t i o n f o r a l l the traits 47.3%  i n Group 2, of  the  69  -  traits  i n G r o u p 1 and  f o r most of  the  a c c o u n t i n g f o r from a p p r o x i m a t e l y zero  total variations  i n these t r a i t s .  Age  at  to  first  2 c a l v i n g accounted f o r higher R  values i n a l l f i r s t  traits  c o m p a r e d t o t o t a l l i f e t i m e p r o d u c t i o n and  traits  (2.13% t o  for  Cullage  part  4.97%  V e r s u s 0.0%  t o w h o l e as m e n t i o n e d e a r l i e r  due  l i f e t i m e p r o d u c t i o n and The  that  to r e l a t i o n of  i n t h i s Chapter.  Within herd phenotypic c o r r e l a t i o n s  g i v e n i n T a b l e 8.  longevity  t o 1.52%), e x c e p t i n g  (47.3%) i n Group 1, w h i c h was  calving with  lactation  correlations  o f age  longevity o f age  at  traits  at f i r s t  first are  calving  with  l i f e t i m e p r o d u c t i o n were a l l p o s i t i v e r a n g i n g between  .139  for Milk  T to  .191  f o r Fat/D i n c a s e of Group 1 cows,  but  t h e s e c o r r e l a t i o n s w e r e low  for  age  cows.  at f i r s t  calving with  These r e l a t i o n s h i p s  p r o d u c e d more m i l k and productive l i f e quite who  total  M i l k / D and  indicated  with  the  calving with Kopland  findings  late calving  regression  age  cows.  fat yields.  at f i r s t  Fat  T,  2.25  kg,  .138  kg,  and  .006  kg,  respectively  44.4  kg,  2.23  kg,  .06  kg  (Table 9),  o f age  f o r e a c h month i n c r e a s e  kg,  at  between Within and  F a t / D w e r e 56.4 i n G r o u p 1;  respectively  in first  (1969),  However,  calving.  M i l k / D and  of  not  of Hargrove et a l .  s e a s o n e f f e c t s f o r M i l k T,  .003  day  This i s  c o e f f i c i e n t s adjusted for year  and  cows  a l s o per  (1963) f o u n d a p o s i t i v e a s s o c i a t i o n  l i f e t i m e p r o d u c t i o n and  herd p a r t i a l  that  negative correlations  l i f e t i m e m i l k and  except  F a t / D , i n Group 2  compared t o e a r l y c a l v i n g  i n agreement  Lamb and  non-significant,  f a t d u r i n g l i f e t i m e and  found n o n - s i g n i f i c a n t  first  and  calving  kg,  and  f o r Group 2 age.  Table  8.  W i t h i n h e r d c o r r e l a t i o n s o f age a t f i r s t c a l v i n g (Age), a v e r a g e c a l v i n g i n t e r v a l (C.I.Av.) and l a s t c a l v i n g i n t e r v a l ( C . I . L . ) w i t h p r o d u c t i o n and l o n g e v i t y .  Group 2  Group 1  a Trait  Age  C.I.Av.  C.I.L.  . 179*  .218*  .127*  .091*  .192*  .241*  .115*  . 088*  .188*  .216*  .129*  .091*  .203*  .238*  .117*  . 086*  NA  .039  . 135*  .167*  NA  . 041  .143*  .188*  . 028  .040  .115*  .156*  . 139*  .011  .048  .126*  F a t ,T  .144*  .014  .053  .131*  Milk/D  .185*  . 090*  -.233*  -.142*  Fat/D  .191*  . 098*  -.209*  -.120*  Cullage  . 816*  .097*  . 122*  .180*  Plife  .028  -.006  .117*  . 177*  # Lact  NA  -.017  Milk Fat  1 1  Milk Fat  HY1 HY1  Milk Fat  Age  L L  LLL Milk  T  *  Significantly  a  Traits  different  are defined  from  zero  -.041  (P < . 0 1 ) .  i n p a g e s 28, 29 and T a b l e  4.  .050  Table  9.  W i t h i n h e r d r e g r e s s i o n s ( a d j u s t e d f o r y e a r and s e a s o n e f f e c t s ) o f age a t f i r s t c a l v i n g (Age), a v e r a g e c a l v i n g i n t e r v a l (C.I.Av.), and l a s t c a l v i n g i n t e r v a l (C.I.L.) on p r o d u c t i o n and l o n g e v i t y t r a i t s .  Group 2  Group 1 Trait  c  50.3+1.44  1.31+.092  1.88+.064 '  2.12+.05  .042+.003  46.8+1.7  51.0+1.4  1.25+.09  1. 89+. 063 -  2.14+.05  Milk 1  46.6+1.73  Fat 1 Milk Fat  HY1 HY1  C.I.Av.  Age  Age  b  C.I.L. -.024+.066 .0024+.0025 -.026+.064  .04+.003  .002+.002  Milk L  NA  10.19+2.25  .437+.143  1.73+.103  Fat  NA  .427+.088  .008+.0056  .083+.004  L  LLL  .59+.15  .836+.149  -.0014+.0095  .121+.0068  Milk T  56.41+2.77  44.4+31.2  -22.0+2.0  32.1+1.43  Fat  2.25+.105  2.23+1.19  -.82+.08  1.24+.05  Milk/D  .138+.005  .061+.004  -.009+.003  .0014+.0002  Fat/D  .006+.0002  .003+.0002  -.0003+.00001  .00006+.000007  Cullage  1.02+.005  .915+.058  -.013+.0037  .061+.0027  Plife  .019+.005  -.077+.058  -.014+.0037  .0608+.0027  -.009+.004  -.005+.0003  .0038+.0002  T  NA  # Lact  a  U n i t s a r e kg, except C u l l a g e , d a y s and # L a c t i n numbers.  b  Standard  c  Traits  Plife,  Age i n months, L L L , C.I.Av., C . I . L . i n  error of regression.  are defined  i n p a g e s 28, 29 and T a b l e  4.  - 72 -  Correlations  of longevity  t r a i t s with  c a l v i n g were i n g e n e r a l low e x c e p t i n g t h a t Very high c o r r e l a t i o n  age a t  for cullage.  (.82) o f age a t f i r s t  calving  with  C u l l a g e f o r G r o u p 1, w o u l d be e x p e c t e d i n t h i s s t u d y , C u l l a g e was t h e sum o f age a t f i r s t length. the  The l o w n o n - s i g n i f i c a n t  tendency of l a t e c a l v i n g  productive l i f e also of  reported s i m i l a r trend.  cows i n G r o u p 2 t o h a v e  indicated shorter  cows. H a r g r o v e e t a l . (1969)  Within herd p a r t i a l  regressions  # L a c t a n d P l i f e w e r e -.009 l a c t a t i o n a n d -.077 m o n t h ,  respectively  f o r e a c h month i n c r e a s e  Relationships  of Calving  all  the t r a i t s  i n t h e age a t f i r s t  Interval with  Average c a l v i n g  i n t e r v a l e f f e c t s were s i g n i f i c a n t f o r  Last calving  longevity,  l a c t a t i o n t r a i t s were n o t s i g n i f i c a n t l y a f f e c t e d  last calving  i n t e r v a l (Table 6 ) . .  Within herd phenotypic c o r r e l a t i o n s with  f r o m 0.0% t o  i n t e r v a l had s i g n i f i c a n t  e f f e c t s on l a s t l a c t a t i o n , l i f e t i m e t r a i t s and while f i r s t  calving.  P r o d u c t i o n and L o n g e v i t y  e x c e p t F a t L and L L L , a c c o u n t i n g  2.24% o f t h e v a r i a t i o n .  by  since  c a l v i n g and l a c t a t i o n  negative c o r r e l a t i o n  than e a r l y c a l v i n g  first  p r o d u c t i o n and l o n g e v i t y  of calving  t r a i t s a r e i n T a b l e 8.  interval  First  l a c t a t i o n y i e l d s were s i g n i f i c a n t l y p o s i t i v e l y c o r r e l a t e d a v e r a g e and l a s t c a l v i n g  intervals.  Significant  c o r r e l a t i o n o f m i l k y i e l d e x p r e s s e d as d e v i a t i o n average i n d i c a t e d had  longer calving  that  with  positive from  the highest producers w i t h i n  herd-year  the herd  i n t e r v a l s than t h e i r herdmates p r o d u c i n g  - 73 -  l e s s m i l k , w h i c h i s s u p p o r t e d by M i l l e r e t a l . association carried  i s partly  (1967).  due t o t h e r e a s o n t h a t l a t e  This  calvers  calves f o r shorter periods during the f i r s t  lactation.  O t h e r r e a s o n s c o u l d be more i n t e n s e c u l l i n g o f l o w p r o d u c e r s t h a t d i d n o t b r e e d r i g h t b a c k and t h a t h i g h  producers  m i g h t n o t have r e t u r n e d t o e s t r u s as q u i c k l y as  low producers  lactation  yields  ( T r i m b e r g e r and F i n c h e r ,  interval  intervals.  (.167 and .18 8)  more a t t e n t i o n  which i s further  length, than e a r l i e r l a c t a t i o n s u p p o r t e d by t h e p o s i t i v e  interval  yields,  association  between  interval with  lifetime  but not s i g n i f i c a n t l y  from z e r o , whereas l a s t c a l v i n g correlated  These r e l a t i o n s h i p s  irrespective  interval  life  indicated  than i n e a r l i e r l a c t a t i o n s .  correlations  o f a v e r a g e and l a s t c a l v i n g  r e l a t i o n between c a l v i n g  milk  that farmers are g i v i n g  Significant  m i l k and f a t p r o d u c t i o n p e r day o f l i f e positive  was  with both l i f e t i m e  more t i m e f o r c o n c e p t i o n t o o c c u r i n h i g h y i e l d i n g in  calving  interval.  m i l k and f a t p r o d u c t i o n were p o s i t i v e  significantly positively  higher  t h a t probably dairymen are paying  C o r r e l a t i o n s o f average c a l v i n g  fat.  correlations  than w i t h average c a l v i n g  h i g h y i e l d and l o n g c a l v i n g  and  Last  Slightly  t o the current l a c t a t i o n y i e l d ,  the lactation  different  parturition  o f l a s t l a c t a t i o n m i l k and f a t w i t h l a s t  (.135 a n d .143) i n d i c a t e  of  1956).  a l s o showed s i g n i f i c a n t p o s i t i v e  w i t h b o t h average and l a s t c a l v i n g correlations  after  cows l a t e r  negative  intervals  with  explains that the  i n t e r v a l and l i f e t i m e  yields  -  o f m i l k and  74  f a t were due  s u p p o r t e d by  findings  partial  regressions  calving  effects  respectively  of  -  t o more d a y s i n m i l k w h i c h  is  S m i t h and  Intraherd  adjusted  f o r y e a r and  f o r M i l k T and  f o r e a c h day  Fat  longer  whereas t h e s e v a l u e s were -22.0 for  average c a l v i n g Age  life  the  last  culving  correlations  a v e r a g e and  and  -0.82  ( C u l l a g e ) and  also  calving  and  1.24  the  number o f  calving  o b s e r v e d by  kg,  respectively  length  of  productive  M i l l e r et a l .  data  for genetic  regression  technique  c o e f f i c i e n t s obtained  used to a d j u s t  data of  average c a l v i n g  the  raw  completed  life. with which  (1967).  c o e f f i c i e n t s obtained  model 1 f o l l o w i n g  adjust  productive  lactations  Group 1 cows were a d j u s t e d  regression  the  expected,  Data  using regression  regression  of  with  i n t e r v a l s were e s s e n t i a l l y z e r o ,  Before subjecting records of  kg,  interval,  i n t e r v a l s , which i s  i n t e r v a l i s a part of  last  Adjustment of  to  calving  kg  first  ( P l i f e ) were p o s i t i v e l y s i g n i f i c a n t l y c o r r e l a t e d  since  was  season of  T were 32.10  last kg  (1962).  interval.  at d i s p o s a l  b o t h a v e r a g e and  The  Legates  m o d e l 5. data are  f o r age  The  last  estimates,  first  (model 4 ) .  calving  i n Table  at  calving  analysis  first  interval  were  calving,  according  c o e f f i c i e n t s used 9.  of  Partial  f r o m model 2 a n a l y s i s  regression  given  at  from the  Group 2 cows f o r age  i n t e r v a l and  parameter  Adjustments  to  for  - 75  herd, year,  s e a s o n and  for  mentioned e a r l i e r .  reasons  -  y e a r by  season e f f e c t s were not These e f f e c t s were  f o r by e s t i m a t i n g g e n e t i c p a r a m e t e r s on w i t h i n  done  accounted  herd-year-  season s u b c l a s s b a s i s .  Estimations of Genetic  The g r o u p and  Parameters  number o f s i r e s r e p r e s e n t e d  i n each g e n e t i c  t h e number o f h a l f - s i b s i n d i f f e r e n t g r o u p s  represented  i n Tabie  10.  A summary o f l e a s t s q u a r e s  o f v a r i a n c e a c c o r d i n g t o m o d e l 6 f o r G r o u p s 1 and and  G r o u p 2 s e p a r a t e l y a r e shown i n T a b l e s 11 and 2  t a b l e s show R mathematical  are analysis  2 combined 12.  These  values f o r the e f f e c t s i n c l u d e d i n the model, t h a t i s , the p r o p o r t i o n of the  v a r i a t i o n i n e a c h o f t h e t r a i t t h a t was the e f f e c t s of herd-year-season, g e n e t i c group.  accounted  total f o r by f i t t i n g  g e n e t i c g r o u p and  I n c o m b i n e d G r o u p s 1 and  sire within 2  2 data, t o t a l  R  values f o r p r o d u c t i o n t r a i t s w i t h the exception of M i l k T and F a t T, w e r e h i g h e r for  l o n g e v i t y t r a i t s , such  (33.5%  to 34.5%)(Table  v a r i a t i o n i n M i l k T, to  (37.6%  residual  11).  as c u l l a g e , P l i f e and A l a r g e percentage  F a t T and  (over 65%).  t h e f a c t o r s w h i c h c a n be of l i t t l e  t o 58.7%) c o m p a r e d t o  # Lact of the  total  longevity traits i s attributable  This reveals t h a t i n these identified  c o n s e q u e n c e as s o u r c e s  l i f e t i m e p r o d u c t i o n and  those  and m e a s u r e d a r e  o f v a r i a t i o n among  l o n g e v i t y t r a i t s , whereas  analyses apparently total  unidentified  T a b l e 10.  Number o f s i r e s a n d d a u g h t e r s f o r G r o u p s 1 and 2 c o m b i n e d .  i n each g e n e t i c  P e r i o d s D u r i n g Which S i r e s Were B o r n  G e n e t i c Group  group:  No. o f S i r e s  No. o f  Daughters  Gl  January.; .194 6 through.: December .1948  18  3282  G2  January  194 9 t h r o u g h  December 1951  23  7919  G3  J a n u a r y 1952 t h r o u g h  December 1954  35  7483  G4  January  1955 t h r o u g h  December 1957  48  9383  G5  January  1958 t h r o u g h  December 1960  14  2671  138  30738  Total:  Summary o f t h e a n a l y s i s o f v a r i a n c e f o r a d j u s t e d f o r Groups 1 and 2 combined  T a b l e 11.  R Total Fitted  Total C • S • S. • . b  Trait-  Herd-Year Season  2  Values  data: 3  (%)  Genetic Group  Sire/Genetic Group  57.2  46.8  . 06  2.02  7  58.7  48.3  .04  2.21  17.28xl0  9  37. 6  32.7  . 08  2.93  2.48xl0  7  38.7  33.4  . 05  3.22  50.74xl0  9  43.4  37.4  . 05  1.80  7.65xl0  7  43.6  37.6  . 034  2.00  LLL  16.45xl0  7  32.0  30.0  . 03  1.19  Milk T  80.48X10  33. 6.  30.4  . 038  1.78  Fat  11.57xl0  9  33.8  30.5  . 033  1.85  Milk/D  2.01xl0  5  56.0  46.5  . 054  2.00  Fat/D  3.07xl0  2  55.6  46.2  .033  Cullage  2.92xl0  7  33.6  31.1  Plife  3.OOxlO  7  34. 5  # Lact  1.54xl0  5  Milk 1 Fat  1  Milk Fat  HY1 HY1  Milk L Fat  L  T  D.F.  24.16xl0  9  3.58xl0  1 1  30737 values are s i g n i f i c a n t  C  2.40  . 032  C  1.56  30.7  . 032  C  1.54  33.5  31.1  . 036  8323  8186  4  a  A l lR  (P <  b  T o t a l c o r r e c t e d sums o f s q u a r e s  c  N o t s i g n i f i c a n t a t .05 l e v e l .  d  T r a i t s a r e d e f i n e d i n p a g e s 2 8 , 29 a n d T a b l e 4.  1.48 133  .05) u n l e s s o t h e r w i s e s t a t e d . 2 2 2 (kg e x c e p t C u l l a g e , P l i f e i n month a n d L L L d a y ) .  Table  12.  Summary o f t h e a n a l y s i s o f v a r i a n c e  f o r adjusted  R Total C.S.S.  Trait  Milk Fat  1 1  Milk Fat  HY1 HY1  Milk Fat  L L  LLL Milk  T  Total Fitted  2  Values  data:  f o r Group  (%)  3  Herd-YearSeason  Genetic Group  Sire/Genetic Group  16.71xl0  9  64.1  53.4  .04  1. 68  2.44xl0  7  65.8  55.0  .025  1.95  11.09xl0  9  44.8  39.6  .054  2.59  1.60xl0  7  46.3  40.4  . 036  3.07  34.41xl0  9  52.4  46.6  .025°  1.38  5.29xl0  7  52. 6  47.0  .016  1.63  12.34xl0  7  39.2  36.8  . 049  1.28  41.7  38.3  . 045  1.67  54.33X10  1 1  c  7.84xl0  9  42.1  38.7  .04  1.79  Milk/D  1.38xl0  5  62.2  52.7  . 055  1.86  Fat/D  2.13xl0  2  62.6  53.3  . 04  Cullage  1.84xl0  7  40.7  38.3  Plife  1.84xl0  7  40.7  #  9.47xl0  4  Fat  T  Lact  D.F.  22391 values  are s i g n i f i c a n t  .028  1.48  38.3  .029  C  1.47  40.7  38.2  . 034°  1.41  7775  7638  4  133  All R  b  Total corrected  sums o f s q u a r e s  c  Not  a t .05  d  Traits  significant  are defined  (P  < .05) u n l e s s o t h e r w i s e s t a t e d . 2 2 (kg e x c e p t c u l l a g e , P l i f e i n month and  level.  i n pages  2.35 C  a  28,  29 and T a b l e  4.  2.  L L L day  2  ).  -  factors  grouped t o g e t h e r  o f a l a r g e p a r t of the  79  as  -  sources  total  of r e s i d u a l  variation  are  i n these  the  cause  traits.  In  2 Group 2 d a t a , all  t h e model a c c o u n t e d  the t r a i t s  compared t o combined d a t a  groups, the major p a r t o f the herd-year-season variation. higher due  effects  Reduction  due  t o g e n e t i c g r o u p and  total  accounting  i n Group  except  LLL,  Cullage,  and  though s i g n i f i c a n t 1.19% in  t o 3.22%  Group  Genetic  # Lact  traits,  s e t and  were  reduction effects  set.  f o r a l l the  traits,  M i l k L,  Sire  accounted  2 combined and  total  Fat  L,  effects for only  1.28%  to  3.07%  2. trends  genetic progress i n Table  longevity 7.  i n combined d a t a  the to  effects  2 a n a l y s i s while  i n Group 2 d a t a .  i n G r o u p s 1 and  L e a s t squares  are  due  f o r 30-55% o f t h e  i n combined  f o r a l l the  for  In b o t h  r e d u c t i o n was  were s i g n i f i c a n t  Cullage, P l i f e  Plife,  set.  R  s i r e w i t h i n g e n e t i c group  were h i g h f o r most o f t h e t r a i t s group e f f e c t s  total  to herd-year-season  f o r a l l the t r a i t s  Genetic  for larger  13.  traits  T h e r e was  per  year  Genetic are  of f i v e  for production group t r e n d s  shown g r a p h i c a l l y  practically  l a c t a t i o n m i l k and s i r e s born  constants  no  fat yields  g e n e t i c groups and  longevity  i n production i n Figures  genetic progress  in  among t h e d a u g h t e r s  d u r i n g p e r i o d 1952-57, t h e  reason  5  and traits  and through  first of  the  f o r which i s not  Table  13.  G e n e t i c group l e a s t squares c o n s t a n t s and g e n e t i c p r o g r e s s p e r y e a r f o r p r o d u c t i o n and l o n g e v i t y t r a i t s : f o r G r o u p s 1 and 2 combined. G e n e t i c Group G4 (1955-57)  G3 (1952-54)  G5 (1958-60)  1 Genetic Progress Per Year  Gl (1946-48)  G2 (1949-51)  -91.8  5.4  -3.3  -5.7  95.4  31.2  -2.82  .77  -.52  -.09  2.66  .91  -88.2  6.5  -5.3  -7.7  94.7  30.5  - 2 . 67  .85  -.56  -.22  2.60  .88  Milk L  -112.9  -36.9  4.5  18.8  126.5  39.9  Fat L  -4.21  -.95  .20  1.13  3.83  1.34  2. 64  -.70  -.43  2.99  -4.50  -1.19  Trait  Milk  1  Fat 1 Milk Fat  HY1 HY1  LLL  3  ?  Milk T  -546.7  -744.8  -271.2  26.2  1536.5  347.2  Fat T  -17.45  -27.95  -9.50  1.52  53.40  11. 8  Milk/D  -.19  -.11  . 07  -.04  .26  .08  Fat/D  -.0063  -.0033  . 0026  -.0005  . 0075  .0025  Cullage  -1.11  -1.14  -.74  .30  2.70  .64  Plife  -1.11  -1.16  -.75  .29  2.72  .64  # Lact  -.0854  -.0827  -.0612  .0149  .2145  .05  1  U n i t s a r e k g , e x c e p t c u l l a g e , P l i f e a r e i n m o n t h s , L L L i n d a y s and # L a c t i n number.  2  B i r t h year o f s i r e s .  3  T r a i t s a r e d e f i n e d i n p a g e s 28, 29 and T a b l e  4.  - 81 -  1 0^51^5^  (  1 9 4 6 _ 4 8  2  3  4  5  ) (1949-51) (1952-54) (1955-57) (1958-60) Genetic group  -  82  -  Figure 6. Genetic group trends of lifetime milk and lifetime fat yields : For Groups 1 and 2 combined.  Birth year (. of sires  1946  _ ) 48  (1949-51)  (1952-54)  Genetic group  (1955-57)  (1958-60)  - 83 -  Figure 7. Genetic group trends of length of productive l i f e and number of lactations completed : For Groups 1 and 2 combined.  Genetic group  - 84 -  known.  However, g e n e t i c t r e n d s  length of productive  for total lifetime  l i f e a n d number o f l a c t a t i o n  w e r e c o n s i s t e n t l y upward d u r i n g t h e w h o l e p e r i o d and  7).  Annual genetic progress  change p e r y e a r belonging and  than estimates America.  reported  In other  i n which f i r s t grouping  sires  These  estimates  populations was made  daughter appeared i n the r e c o r d .  Considering  s i r e s produce A . I . daughters,  5 years  In t h i s  of b i r t h , covering  represents  studies reported,  the present  study would r e -  an e a r l i e r p e r i o d compared w i t h  and g e n e t i c p r o g r e s s  during the e a r l i e r period. lactation milk  Thus,  other  m i g h t have been  slower  Annual genetic trend f o r l a s t  (39.9 kg) a n d f a t (1:34 k g ) , w h i c h w e r e  l a t e r , were h i g h e r  a  a s t h e age when m o s t  g e n e t i c t r e n d f o r t h e p e r i o d 1951 t h r o u g h 1965.  t h i s study  milk  i n which s i r e entered A.I. or  was on t h e b a s i s o f y e a r  p e r i o d 1946-1960.  present  for Holstein  of  lactation  studies s i r e grouping  e i t h e r on t h e b a s i s o f y e a r  study,  (Figures 6  i n average a d d i t i v e g e n e t i c values  f a t w e r e 31.2 k g a n d .91 k g , r e s p e c t i v e l y .  in North  completed  from twice the  t o d i f f e r e n t g e n e t i c groups f o r f i r s t  are lower  year  calculated  production,  compared t o f i r s t  completed  l a c t a t i o n m i l k and f a t .  Daughters of the s i r e s born d u r i n g the l a t e r p e r i o d produced more m i l k a n d f a t d u r i n g l i f e t i m e a n d a l s o s t a y e d the herd  compared t o d a u g h t e r s o f t h e s i r e s b o r n d u r i n g  period, which i s evident traits  longer i n  ( F i g u r e s 6 and  from the g e n e t i c group t r e n d s  earlier f o r these  7 ) . The a n n u a l g e n e t i c p r o g r e s s f o r  t o t a l m i l k a n d f a t w e r e 347.2 k g and 11.8 k g , r e s p e c t i v e l y  and  - 85 -  those  f o r length of productive l i f e  completed were  Genetic  .64 month  and number o f l a c t a t i o n s  and .05 l a c t a t i o n p e r y e a r .  components o f v a r i a n c e and  covariance  Once s i g n i f i c a n t s y s t e m a t i c , e n v i r o n m e n t a l  effects  w e r e e l i m i n a t e d f r o m t h e d a t a by a p p r o p r i a t e a n a l y s i s , i t was p r e s u m e d t h a t o n l y g e n e t i c and random variability  remained.  Because df the d e s i g n o f the present  s t u d y , t h e g e n e t i c and e n v i r o n m e n t a l and  this  environmental  components were  separable,  s e p a r a t i o n y i e l d e d e s t i m a t e s o f v a r i a n c e components,  heritabilities, correlations.  and g e n e t i c , e n v i r o n m e n t a l In the present  of the genetic v a r i a b i l i t y  phenotypic  study only the a d d i t i v e p o r t i o n  was- e s t i m a t e d  additive genetic v a r i a b i l i t y  and  and s i n c e n o n -  c o u l d n o t be e s t i m a t e d , i t was  assumed t h a t g e n e t i c p a r a m e t e r s i n c l u d e d o n l y a d d i t i v e while environmental of a d d i t i v e  parameters i n c l u d e d a l l e f f e c t s e x c l u s i v e  effect.  Since estimates of a l l p o s s i b l e covariances  between  t r a i t s u n d e r s t u d y w e r e d e s i r e d , t h e same l i n e a r m o d e l used f o r a l l t h e t r a i t s . expected  effects  was  The c o v a r i a n c e i n t e r m s o f t h e  c o v a r i a n c e components c o r r e s p o n d s  to the  expected  v a r i a n c e c o m p o n e n t s when t h e l i n e a r m o d e l u s e d t o a n a l y z e t h e two v a r i a b l e s i s t h e same.  The e x p e c t e d  values of  v a r i a n c e and c o v a r i a n c e c o m p o n e n t s f o r t h e random i n t h e a n a l y s i s o f model 6 a r e g i v e n i n T a b l e  14.  effects The  The expected components o f v a r i a n c e and c o v a r i a n c e f o r two t r a i t s f i t t i n g the same model.  T a b l e 14.  Source of Variation  Degrees of Freedom  Herd-Year-Season  Expected V a r i a n c e Component f o r T r a i t #1 2 ^ + k. 6H. U e^ 4 1  h-1  G e n e t i c Groups  g-1  Expected V a r i a n c e Component f o r T r a i t #2  g*  e  + k  2  2 ^ + k. 0H_ (fe 4 2  rr ^ . \ u e^e + k  2  (S:G) + k 9 G 1  Expected Component o f Covariance Between T r a i t s #1 and #2  3  1  2  +k <T (S:G) +k ©G 2  2  3  2  ( T e ^ + k ^ S : G ) (S :G) + 1  k  S i r e s / G e n e t i c Groups  Residual  s-g  +  ^ (T  (StG^  Q- +k (T e  x  (S:G)  2  eGj^ e G  3  0e e +k 1  2  1  +  +  ^  ^  2  2  CT(S:G) (S:G) 1  N...[<h-l) (g-l) (s-g>]  ^„ GH^ © 2 H  4  CTe  i e  2  - 87  -  v a r i a n c e component b e t w e e n s i r e s t h e n a r r o w s e n s e and c o m p o n e n t , and  the r a t i o  the geometric  yields  the h e r i t a b i l i t y i n  between the s i r e  mean o f t h e s i r e  covariance  variance  components y i e l d s  genetic correlation.  B e t w e e n and w i t h i n  s i r e v a r i a n c e and  c o v a r i a n c e components a s s o c i a t e d w i t h  each t r a i t s are summarized i n Appendix T a b l e number o f d a u g h t e r s 9 was  121.4  per s i r e  (K^)  4.  The  calculated using  f o r c o m b i n e d s e t o f d a t a and  7 8.3  weighted equation  f o r Group 2  cows.  Herifability  estimates  Heritability sib  c o r r e l a t i o n s are g i v e n i n Table  separate The  two  those (.14 and  15.  The  e s t i m a t e s f o r c o m b i n e d G r o u p s 1 and sets of estimates are e s s e n t i a l l y  for last and  .14).  t h a n one was  estimates o b t a i n e d from p a t e r n a l  .16)  lactation  m i l k and  half-  t a b l e shows 2 and  Group  t h e same e x c e p t i n g  f a t , w h i c h were  higher  i n combined s e t compared t o Group 2 d a t a  (.11  S i n c e t h e p o p u l a t i o n o f cows w h i c h c o m p l e t e d more lactation  (Group 2) r e p r e s e n t a s e l e c t e d g r o u p , i t  f e l t that h e r i t a b i l i t y estimates  from the combined s e t ,  w h i c h r e p r e s e n t a more random g r o u p , a r e more  reliable.  T h u s , t h e d i s c u s s i o n on h e r i t a b i l i t y e s t i m a t e s w i l l be to  2.  limited  combined s e t . H e r i t a b i l i t i e s of f i r s t  obtained i n this ( F r e e m a n , 1960;  lactation  study were lower than Gacula  e t a l . , 1968;  m i l k and  fat  some e s t i m a t e s  reported  Blanchart et a l . ,  1966;  T a b l e 15.  H e r i t a b i l i t y estimates f o r f i r s t lactation p r o d u c t i o n , and l o n g e v i t y t r a i t s .  yields,  Groups 1 & 2 Trait  3  Heritability  lifetime  Group 2 S.E.  Heritability  S.E.  .22  .025  .20  .025  .25  .027  .25  . 029  .22  .024  .20  .025  HY1  .24  .027  .25  . 029  L  .14  .017  .11  . 016  .16  .019  .14  . 019  .06  . 010  .07  .012  .11  . 0T5  .11  .016  T  .12  .015  .12  .017  Milk/D  .21  . 024  .21  . 026  Fat/D  .25  .028  .28  .032  Cullage  .10  . 013  .09  .014  Plife  .10  . 013  .09  .014  #  .09  . 012  .08  .013  Milk Fat  1 1  Milk Fat  HY1  Milk Fat  L  LLL Milk Fat  T  Lact  a  T r a i t s a r e d e f i n e d i n p a g e s 28, 29 and T a b l e  4.  - 89 -  Schaeffer  e t a l . , 1975  and  L i n and  A l l a i r e , 1 9 7 8 ) , but  w e l l w i t h i n the range o f e s t i m a t e s researchers Gill  and  (Gaunt e t a l . , 1966;  A l l a i r e , 1976  populations.  Reported  m i l k and  .14  from  to  and  Wilcox  Ahunu, 1978)  estimates  .45  o b t a i n e d by  other  e t a_l. ,  1971;  for Holstein  range from  for fat.  were  .12  to  Some o f t h e s e  .37  for  studies  have used  d a u g h t e r - d a m r e g r e s s i o n , w h i c h method a c c o r d i n g  the  o f Van  study  heritability method. be  due  Vleck  estimates  were a l s o  literature,  gives  to h a l f - s i b  obtained  are d i f f i c u l t and  estimates  in this  higher  correlation  s t u d y may  lower  compared t o t h o s e  of l a s t  to i n t e r p r e t  subsequent  Heritabilities  of  the corresponding  i n Table  lactation since last  lactations  up  last lactation first  lactation  1955).  Vleck, The  particularly Pirchner  genetic  reason  J o h n s o n and  f o r lower  the second  (1969)  lactation  1963;  c o u l d be  potential  in  in this  lactation  study  included  lactation.  f a t were l o w e r  than  estimates, which i s i n (Freeman, 1960;  Corley,  1961;  Barr  and  h e r i t a b i l i t y of l a t e r  lactation,  according  t h a t most cows s t a r t  w e l l c o n d i t i o n e d and  and  However, g e n e t i c  obtained  m i l k and  partly  grouping.  available  16.  to tenth  agreement w i t h t h e e a r l i e r s t u d i e s Van  also  for last lactation milk  w h i c h i s summarized  parameter estimates  and  (1965)  t o r e m o v a l o f g e n e t i c t r e n d s by u s i n g s i r e  yields  first  Bradford  compared  Lower e s t i m a t e s  Heritability fat  and  to  thus  much b e t t e r t h a n  lactations,  to their  can d i s p l a y i n the  Johansson,  second  their  first real  lactation,  Heritability  T a b l e 16.  estimates of f i r s t  three lactations  i n Holstein. Fat  Milk Yield  Yield  L a c t a t i o n Number Source Freeman  (1960)  (1)  B a r r a n d Van V l e c k Johnson  and C o r l e y  Johansson  (1961)  (1955)  Gacula e t a l . Gaunt e t a l .  (1966)  (1971)  and A l l a i r e  (1976)  Schaeffer et a l .  (1975)  H a r g r o v e e t aJL.  (1969)  (5) (6)  (1978)  L i n and A l l a i r e  (1978)  M o l i n u e v o and Lush (1) (2) (3) (4) (5) (6)  (4)  (1966)  Wilcox et a l .  Ahunu  (2)  Standard Standard Standard Standard Standard Standard  2  3  1  2  3  .36  .24  .26  .43  .35  .26  .26  .27  .21  .35  .22  .16  .33  .22  .33 33  10  24  09  05  (1)  (1968)  Blanchart et a l .  Gill  (1963)  1  (19 64)  37  45  29  29  24  24  23  25  12  14  29  ,28  39  37  23  25  39 (3)  30  09  d e v i a t i o n s r a n g e d f r o m .02 t o .09. d e v i a t i o n s v a r i e d b e t w e e n .05 and .10 d e v i a t i o n s r a n g e d f r o m .10 t o .23. e r r o r s w e r e .21 a n d .22. e r r o r was .08 f o r b o t h t h e t r a i t s . e r r o r s w e r e .08 a n d .09.  08  ,29  -  w h i c h some e n t e r production  i n depleted  i n the f i r s t  length of f i r s t additional  source  for  interval  Though t h e v a r i a b l e  i s considered  of residual variation  in this  calving  c o n d i t i o n because.of h i g h  lactation.,  calving  subsequent l a c t a t i o n s , estimates  91 -  this  study  interval.  should  f o r s e c o n d and  not a f f e c t  have a f f e c t e d or i n other  A l s o , a cow's t e r m i n a l r e c o r d may  the r e s u l t s  studies.  these  provided  reasons,  Historically,  i t was f e l t estimate  t h e a s s u m p t i o n o f random Total milk  records  first  lactation  insofar  as they  o r by p r e f e r e n t i a l  an u n b i a s e d  here. may  h a s n o t been i n v e s t i g a t e d i n t h i s  have b e e n c o n s i d e r e d more r e l i a b l e  For  n o t known  o f t e r m i n a l and n o n - t e r m i n a l  b i a s e d by s e l e c t i o n  heritability  s i n c e t h e r e c o r d s were a d j u s t e d  o f t e n be a b n o r m a l i n ways and f o r r e a s o n s How t h e m i x t u r e  as an  records are less  f e e d i n g and management.  that f i r s t  lactation  records  and a r e more i n k e e p i n g  with  sampling.  production during  l i f e was low b u t 2  significantly estimate with  to The  for total  significant  other  studies  overall  this  study  (h  i n agreement r e - s i g n i f i c a n c e ,  lifetime  b u t lower (Hargrove  impression  significant, in  in this  H a r g r o v e e t a l . (1969)  estimate also  heritable  study  .11 + . 0 1 5 ) , an  though not i n magnitude,  (Table 17). 2 f a t (h  =  Heritability  = .118 + .015)  i n magnitude  compared  e t aJL. , 1969; G i l l  from p r e v i o u s  low h e r i t a b i l i t y  was  and A l l a i r e ,  1976).  r e s e a r c h was t h a t t h e  estimates  f o r total milk  a r e w i t h i n the range of estimates  and f a t  i n view o f  •ii  T a b l e 17.  H e r i t a b i l i t y e s t i m a t e s o f l i f e t i m e p r o d u c t i o n and longevity i n Holstein.  Lifetime Source  (1)  Hargrove e t a l . (1969) Plowman and Gaalaas Gill  and A l l a i r e  Production  Total Milk  Total Fat  .18  .18  Milk/ Day  White and N i c h o l s (1965)  Total Life  Productive Life  (2)  .25  .26  .4  .15  .14  .26  .25  .23 .13  .14  (3)  .18  P a r k e r e t a l . (1960)  .37  Wilcox e t a l . (1957) .05-.14  M i l l e r e t a l . (1967) Evans e t a l . (1964)  No. o f Lactations  .148  (1960)  (1976)  Longevity  .28  (4)  (1)  Standard e r r o r  ranged from  .08 t o .09.  (2)  Standard e r r o r  ranged from  .09 t o .11.  (3) ,  Standard e r r o r was .17 f o r  (4)  Standard e r r o r was .12 f or milk/day and .09 f o r  both the t r a i t s . productive l i f e .  0.0  - 93 -  errors of estimation i n previous studies. Though t h e s i r e l e n g t h was s i g n i f i c a n t 2 was v e r y l o w (h component in this  component  (P < . 0 5 ) ,  lactation  the h e r i t a b i l i t y  = .06 + .01) i n d i c a t i n g  and a r e l a t i v e l y  trait.  for last  low g e n e t i c  high environmental  This t r a i t  i s probably  estimate  variability  v e r y much d e p e n d e n t  on management d e c i s i o n s a n d d e p e n d s on e c o n o m i c c o n d i t i o n s , such  as r e l a t i v e  m i l k a n d b e e f p r i c e a t t h e t i m e when  culling  d e c i s i o n i s made. M i l k p e r d a y o f p r o d u c t i v e l i f e was e s t i m a t e d t o 2 h a v e m o d e r a t e h e r i t a b i l i t y (h = .28 + .12 t o .4 + .11) by E v a n s e t a l . (1957) a n d G i l l and A l l a i r e ( 1 9 7 6 ) . The e s t i m a t e 2 from t h i s  study  reported.  (h  = .21 + .024) was l o w e r  than  F a t p e r day o f p r o d u c t i v e l i f e , w i t h  heritability  o f .25 + .028, o b t a i n e d i n t h i s  comparison from p r e v i o u s s t u d i e s . literature  by L a r s o n  m a g n i t u d e and r e l a t i v e l y  as z e r o .  small standard  considered that the present  s t u d y , h a d no  estimate  heritability In view of the  error,  i t is  i s reliable.  Three measures o f l o n g e v i t y u t i l i z e d age a t d i s p o s a l ,  moderate  The o n l y r e p o r t i n  e t a l . (1951) g a v e a  e s t i m a t e o f f a t p e r day o f l i f e  those  length of productive l i f e  l a c t a t i o n completed e x h i b i t e d s i g n i f i c a n t  i n this  study,  and number o f but very low  heritabilities  o f .10 + .013, .10 + .013 and .09 + .012,  respectively.  W h i t e and N i c h o l s  heritability  (1965) r e p o r t e d a 2 w i t h r a t h e r l a r g e s a m p l i n g e r r o r (h = .14 + .17)  - 94 -  for  age a t l a s t c a l v i n g .  Estimates of s i m i l a r magnitude  h a s a l s o b e e n r e p o r t e d by Plowman and G a a l a a s (196 0) P a r k e r e t a l . (1960).  Gill  and A l l a i r e  higher estimate, while M i l l e r  and  (1976) r e p o r t e d  e t a l . (1967) o b t a i n e d  estimates  (.05 t o .14) w i t h i n w h i c h t h e e s t i m a t e s o f t h i s s t u d y H e r i t a b i l i t y estimates of very reported  l a r g e v a r i a t i o n have been  (0.0 t o .25) f o r l e n g t h o f p r o d u c t i v e l i f e .  and A l l a i r e  falls.  (1976) e s t i m a t e d t h e h e r i t a b i l i t y  Gill  of h e r d l i f e  .25 + .09 a n d E v a n s e t a _ l . (1964) o b t a i n e d p r a c t i c a l l y g e n e t i c component  f o r length of productive l i f e .  as  no  The r a n g e  o f e s t i m a t e s r e p o r t e d f o r t h e number o f l a c t a t i o n s  initiated  2 (h  = .13 t o .37) i s h i g h e r t h a n t h e e s t i m a t e o b t a i n e d i n  the present  study.  Genetic  improvement i n d a i r y c a t t l e has been  achieved  p r i m a r i l y by s e l e c t i o n f o r t h e a d d i t i v e p o r t i o n o f t h e t o t a l genetic effect.  To o b t a i n g e n e t i c p r o g r e s s by  direct  s e l e c t i o n , t h e t r a i t s must h a v e a s i g n i f i c a n t  genetic  component.  component  In general, a s i g n i f i c a n t genetic  i n d i c a t e s t h a t s e l e c t i o n on t h a t t r a i t  will  result  o f t h e p o p u l a t i o n mean i n t h e d e s i r e d d i r e c t i o n . present  i n change In the  study, i t i n d i c a t e d t h a t a p o r t i o n of the genotype  o f t h e cow was r e s p o n s i b l e f o r e s t a b l i s h i n g t h e m e a s u r e d l e v e l of t r a i t s  s u c h as f i r s t  l a c t a t i o n y i e l d s and  yields  p e r d a y o f p r o d u c t i v e l i f e , and t h a t t h e a d d i t i v e e f f e c t o f t h e genes were a m a j o r c o n t r o l l i n g  f a c t o r i n t h i s genotype.  I t was n o t e d t h a t m o s t e s t i m a t e s o f f i r s t  lactation  yields  -  w e r e a b o v e .24, i n d i c a t i n g  95  -  some s c o p e o f g e n e t i c  i n t h e s e t r a i t s by d i r e c t s e l e c t i o n . heritability traits  improvement  The m a j o r i t y o f t h e  e s t i m a t e s o f l i f e t i m e p r o d u c t i o n and  i n Holstein  longevity  r a n g e d b e t w e e n .13 a n d .18, t h u s ,  l i t t l e g e n e t i c p r o g r e s s c o u l d be e x p e c t e d i n t h e s e by d i r e c t  very  traits  selection.  Correlations  As an a l t e r n a t i v e  to direct  selection  there i s another  a p p r o a c h , namely i n d i r e c t s e l e c t i o n .  T h i s method i s e f f e c t i v e  when t h e t r a i t s  have a s i g n i f i c a n t  involved i n selection  genetic correlation result the  and t h u s s e l e c t i o n  i n a s i m u l t a n e o u s change i n a n o t h e r t r a i t because  i n d i v i d u a l g e n o t y p e s i n v o l v e d w i t h t h e t r a i t s h a v e some  portion  i n common.  The r e l a t i v e s i z e o f t h i s p o r t i o n i s  e s t i m a t e d by t h e g e n e t i c c o r r e l a t i o n . affects of the  f o r one t r a i t w i l l  T h i s common g e n o t y p e  t h e two t r a i t s t h r o u g h t h e phenomenon o f  gene e f f e c t s . heritability  Response t o i n d i r e c t s e l e c t i o n o f t h e t r a i t used i n d i r e c t l y ,  pleiotropy d e p e n d s on  the genetic  v a r i a n c e o f t h e t r a i t i n w h i c h change i s s o u g h t , t h e g e n e t i c correlation  b e t w e e n t h e two t r a i t s a n d t h e s e l e c t i o n  differential. to d i r e c t of  The s u c c e s s o f i n d i r e c t s e l e c t i o n  selection  these f a c t o r s .  compared  w i l l d e p e n d on t h e r e l a t i v e m a g n i t u d e In practice,  e a s e a n d economy o f m e a s u r e -  ment may become a c o n s i d e r a t i o n i n t r a i t s e l e c t i o n .  A  Table  18.  3  Milk 1  Trait  Milk  Phenotypic c o r r e l a t i o n s ( a b o v e diagonal) and g e n e t i c (below d i a g o n a l ) : f o r combined Groups 1 and 2.  1  Fat 1  Milk HYl  Fat HYl  Milk L  Fat L  LLL  Milk T  Fat T  Milk /D  Fat /D  Cull age  Plife  #Lact  .82  .98  .80  .56  .44  .21  .36  .33  .77  .57  .28  .28  .26  .81  .98  .46  .55  .19  .33  .36  .60  .75  .28  .28  .26  .82  .55  .43  .21  .36  .33  .76  .57  .27  .27  .25  .45  .55  .19  .33  .36  .59  .74  .27  .27  .26  .90  .35  .58  .56  .72  .60  .51  .51  .49  .33  .54  .57  .60  .72  .49  .50  .47  .18  .18  .17  .17  .16  .16  .08  .99  .47  .43  .98  .98  .97  .44  .47  .97  .98  .96  .79  .34  .34  .33  .34  .34  .33  1.0  .99  .49  Fat 1  1.0  .49  .50  1.0  .49  Milk L  .83  .47  .83  .48  Fat L  .37  .85  .37  .85  .65  * .54  .41  .53  •  4 1  .70  .55  Milk Fat  HYl HYl  LLL  correlations  Milk T  .56  .49  . 57  .49  .87  .75  .69  Fat T  .42  .61  .43  .62  .77  .87  .66  .96  Milk/D .  .93  .44  .93  .45  .93  .48  .61  .71  .57  Fat/D  .34  .93  .34  .93  .50  .95  .46  .59  .74  .43  Cullage  .44  .45  .45  .46  .78  .75  . 66  .98  .97  .57  .57  Plife  .44  .46  .45  .47  .78  .75  .66  .98  .97  . 58  .57  1.0  #Lact  .41  .44  .42  .45  .76  .74  .61  .98  .97  .55  .56  1.0  a  A l l correlations significantly  b  Standard e r r o r o f g e n e t i c c o r r e l a t i o n ranged from .0 01 to  c  V a l u e s h i g h e r than  d  T r a i t s are d e f i n e d i n pages 28,  .997  d i f f e r e n t from zero  rounded to  1.0.  29 and T a b l e  4.  (P  <  .01). .098.  .99 C  1.0  C  T a b l e 19.  •. c  Trait  Phenotypic c o r r e l a t i o n s (above d i a g o n a l ) and g e n e t i c c o r r e l a t i o n s (below d i a g o n a l ) : f o r Group 2.  Milk 1  Milk 1  Fat  Milk HYl  Fat HYl  Milk L  Fat L  LLL  Milk T  Fat T  Milk /D  Fat /D  Cullage  Plife  #Lact  .79  .98  .77  .39  .26  .16  .30  .26  .72  .51  .18  .18  .16  .77  .98  .29  .40  .15  .26  .31  .54  .71  .18  .18  .17  .79  .39  .26  .16  .30  .26  .71  .51  .18  .18  .16  .28  .39  .15  .26  .31  .53  .70  .18  .18  .17  .87  .44  .46  .43  .72  .58  .35  .35  .32  .38  Fat 1 Milk  Fat 1  HYl HYl  Milk L  1.0  .39  .38  1.0  .39  .71  .26  .72  .27  .41  .40  .44  .56  .72  .33  .30  .30  .28  .28  .23  .23  .25  .25  .16  .99  .55  .49  .97  .97  . 96  .51  .54  .97  .97  .95  .78  .38  .38  . 36  .37  .37  .35  1.0  .98  Fat L  .11  .77  .13  .78  .48  LLL  .44  .38  .45  .38  .66  .52  Milk T  .40  .29  .43  .31  .84  .64  .74  Fat T  .21  .48  .25  .50  .68  .84  .71  .94  Milk/D  .85  .31  .86  .33  .94  .37  .63  .72  .54  Fat/D  .19  .86  .21  .87  .43  .96  .53  .55  .75  .41  Cullage  .19  .24  . 22  .26  .68  .63  .69  .96  .95  .51  .51  Plife  .20  .24  .22  . 26  .68  .63  .69  .96  .95  .51  .51  1.0  #Lact  .15  .21  .18  .24  .64  .61  .61  .95  .94  .47  .49  .99  a  A l l c o r r e l a t i o n s s i g n i f i c a n t l y d i f f e r e n t from zero  b  Standard e r r o r s o f g e n e t i c c o r r e l a t i o n s ranged from .001  c  Traits  are d e f i n e d i n pages 28,  29 and Table  4.  (P  <  .01). to  .12.  .98 .99  1  ^ 1  - 98 -  r a t i o n a l d e c i s i o n must b e r e a c h e d  between t h e s t r e n g t h o f  t h e g e n e t i c system and t h e c o n s i d e r a t i o n s o f i t s p r a c t i c a l use.  Some d i s c u s s i o n o f t h e r e l a t i o n s h i p s o f f i r s t  y i e l d s w i t h l i f e t i m e p r o d u c t i o n and l o n g e v i t y w i l l  lactation provide  some i n f o r m a t i o n f o r m a k i n g t h i s d e c i s i o n . Phenotypic and  environmental  one  trait  c o r r e l a t i o n , which includes both  genetic  e f f e c t s may be v e r y u s e f u l f o r p r e d i c t i n g  from another  trait  i n t h e same i n d i v i d u a l ,  however,  i t may be o f no v a l u e a t a l l f o r p r e d i c t i n g i n t h e n e x t generation.  Breeders  are mainly  interested  i n the correlation  of b r e e d i n g v a l u e s w h i c h i s measured by t h e g e n e t i c Thus, a s e p a r a t e d i s c u s s i o n on p h e n o t y p i c c o r r e l a t i o n s among t h e t r a i t s w i l l  be  and g e n e t i c  presented.  A summary o f g e n e t i c a n d p h e n o t y p i c among a l l t r a i t s  i s given i n Tables  c o r r e l a t i o n s f o rboth  i n Appendix Table  5.  correlations  18 a n d 1 9 , f o r g r o u p s 1 and  2 c o m b i n e d and G r o u p 2 d a t a , r e s p e c t i v e l y . environmental  correlation.  A summary o f  combined and Group 2 i s  The b a s i s f o r two s e p a r a t e  sets of  e s t i m a t e s was t h a t t h e e s t i m a t e s b a s e d o n c o m b i n e d f i r s t a n d m u l t i p l e l a c t a t i o n cows ( G r o u p s 1 and 2) w o u l d g i v e a b e t t e r estimates of the c o r r e l a t i o n s since t h i s s e t of data r e p r e s e n t s more a random p o p u l a t i o n compared w i t h m u l t i p l e l a c t a t i o n cows o n l y largely  (Group 2 ) , w h i c h r e p r e s e n t a p o p u l a t i o n  selected for milk yield.  Group 2 d a t a w i l l  Thus, c o r r e l a t i o n s  from  i n d i c a t e t h e e f f e c t o f s e l e c t i o n on  correlation estimates.  The two s e t s o f e s t i m a t e s  differed,  - 99  -  and m o s t o f t h e g e n e t i c c o r r e l a t i o n s G r o u p s 1 and The  b a s e d on  2 were h i g h e r w i t h lower  combined  standard  errors.  lower estimates of the g e n e t i c c o r r e l a t i o n s  r e f l e c t the e f f e c t  of s e l e c t i o n  y i e l d which probably t h i s t r a i t and  reduced  for first  lactation  the l i n k a g e r e l a t i o n  l i f e t i m e p r o d u c t i o n and  the high estimates  i n Group 2  between  longevity.  i n t h e c o m b i n e d s e t was  However,  partly  due  n a t u r e o f t h e d a t a w h i c h had  about o n e - t h i r d of the  f r o m cows c u l l e d  l a c t a t i o n , having  first yields  and  after  first  last lactation yields,  and  c o n s i d e r a t i o n of the c o n d i t i o n s necessary breeding  characteristics reasons,  Phenotypic  The  t o comply w i t h modern  B a s e d on t h e  not  ideal  original above  correlations  correlations.  found between f i r s t  of prime i n t e r e s t  lactation yields  longevity traits.  The  (1978),  in this  with lifetime  significant relationship  l a c t a t i o n m i l k and  by H a r g r o v e e t a l . ( 1 9 6 9 ) , G i l l and Allaire  gave  correlations  were t h o s e o f f i r s t  and  also i n  i t i s c o n s i d e r e d t h a t the combined s e t of d a t a  more r e l i a b l e e s t i m a t e s o f  and  And  c u l l i n g m i g h t have changed t h e  of the population.  records  lifetime  t h e o r y , t h e p o p u l a t i o n o f G r o u p 2 cows was  because s e l e c t i v e  to  identical  less variable  c o m p a r e d t o m u l t i p l e l a c t a t i o n cows.  milk  indicating  study production (r =  .36)  t o t a l m i l k i s matched  Allaire  (1976) and  Lin  the i n c r e a s e i n subsequent  - 100 -  production with the increase i n heifer the i n t e r p r e t a t i o n and  o f t h e r e l a t i o n between f i r s t  l i f e t i m e production  similar  studies,  i s complicated  t h e same w h i c h w i l l  This estimate lactation  was l o w e r  f o r Group 2 d a t a  of f i r s t  ( r = .77) a n d f i r s t  per day o f l i f e  (r = .30). F i r s t o f t h e same m a g n i t u d e (Tables  by e a r l i e r  Relationships of f i r s t  h e r d - y e a r d e v i a t i o n m i l k and f a t w i t h l i f e t i m e t h e same a s t h o s e  305-day m i l k a n d f a t y i e l d s the sets o f data.  18 a n d 1 9 ) .  f a tyield with f a t yield  ( r = .75) a r e s u p p o r t e d  were e s s e n t i a l l y  upward.  l a c t a t i o n m i l k w i t h m i l k per  lactation  s u m m a r i z e d i n T a b l e 20.  lifetime are  bias the c o r r e l a t i o n  f a t as m i l k w i t h l i f e t i m e m i l k  The s t r o n g r e l a t i o n s  lactation  l a c t a t i o n the  and d u r i n g  f a t y i e l d showed a c o r r e l a t i o n  with lifetime  day  lactation  However,  i n t h i s and other  s i n c e f o r cows w i t h s i n g l e  milk y i e l d i n the f i r s t essentially  production.  forfirst  studies  lactation production  lactation  with lifetime production  i n both  M o r e o v e r , 3 05-day y i e l d s w e r e v e r y  highly  correlated  w i t h herd-year d e v i a t i o n y i e l d s  indicating  t h a t t h e y a r e m e a s u r e s o f t h e same u n d e r l y i n g  traits. in  The p a t t e r n o f p h e n o t y p i c  general  correlated  the f i r s t  the l i f e t i m e , probably of v a r i a b l e  calving  correlations  lactation yields  with yields  (r = .98),  p e r day o f l i f e  w e r e more  indicated, highly  than t o t a l y i e l d  during  because i n t h e former case t h e e f f e c t  i n t e r v a l was e l i m i n a t e d .  Table  20.  Summary o f p h e n o t y p i c (above) and g e n e t i c (below) c o r r e l a t i o n s o f f i r s t l a c t a t i o n y i e l d s w i t h l i f e t i m e p r o d u c t i o n and l o n g e v i t y t r a i t s .  Lifetime Total Milk  Source  F i r s t Lactation Milk  Lin  and A l l a i r e and A l l a i r e  Total Fat  Milk/ Day  Total Life  Productive Life  Yield  Hargrove .et a l . (1969) Gill  Longevity  Production  (1976) (1978)  Number o f Lactations  .48  .43  ,38  . 85  .76  ,62  .23  .56  .13  ,05  1.03  1.04  .81  .82  .43  I  .48 Miller  M O r-  ,19-.25  e t . a l . (1967)  ,54-.77 ,45  Evans .et a l . (1964) Parker  White and N i c h o l s  ,197  (1963)  ,216  (1965)  F i r s t Lactation Fat Yield Hargrove e t a l . (1969) Gill  and A l l a i r e  Parker  (1976)  White and N i c h o l s  .45  .40  ,36  .94  .84  ,72  .23  .12  1.08  .83 195  e t a l . (1960)  G a a l a a s and Plowman  I  .22  ,76  e t a l . (1960)  G a a l a a s and Plowman  ,22  (1963)  (1965)  ,188 , 234  1  - 102 -  The c o r r e l a t i o n s o f f i r s t yields with ranging (Table  l o n g e v i t y t r a i t s w e r e s i g n i f i c a n t and  between 18).  producing  l a c t a t i o n m i l k and f a t positive,  .26 and .28 f o r t h e c o m b i n e d s e t o f  This p o s i t i v e association indicates that  h e i f e r s also stayed  longer  longevity t r a i t s  a r e i n T a b l e 21.  high  i n the herd.  The c o r r e l a t i o n s among l i f e t i m e p r o d u c t i o n  total  data  and  H i g h c o r r e l a t i o n s between  l i f e t i m e m i l k and f a t y i e l d s w i t h l o n g e v i t y  traits  (r = .96 t o .98) show t h a t h i g h y i e l d i n g cows a r e a l s o t h e longer (1969),  l i v i n g cows, w h i c h was who  reported  a l s o o b s e r v e d by H a r g r o v e e t a l .  .95 as t h e c o r r e l a t i o n b e t w e e n  lifetime  m i l k and f a t y i e l d s w i t h number o f l a c t a t i o n s i n i t i a t e d . c o n s i s t e n c y o f c o r r e l a t i o n s i n v o l v i n g t h e number o f length of productive  life  or w i t h the other t r a i t s  o r c u l l i n g age w i t h one  lactations,  another  seem t o i n d i c a t e t h a t a l l t h r e e  measures o f l o n g e v i t y r e p r e s e n t r e p l a c e d by t h e o t h e r .  The  t h e same t r a i t and one c a n be  The e x t r e m e l y  high correlation  (.99)  b e t w e e n l i f e t i m e m i l k and l i f e t i m e f a t a l s o i n d i c a t e t h a t one o f t h e s e  traits will  adequately  measure t h e l i f e t i m e  production.  Genetic c o r r e l a t i o n s  Beyond t h e e s t i m a t i o n o f h e r i t a b i l i t y  of  production  and l o n g e v i t y t r a i t s , t h i s s t u d y  a l s o examined r e l a t i o n s h i p s  among t h e s e  those  traits, particularly  involving first  Table  Trait*  3  21.  Milk L  Milk L  Phenotypic (above diagonal) and g e n e t i c (below diagonal) c o r r e l a t i o n s among l i f e t i m e p r o d u c t i o n and l o n g e v i t y t r a i t s : f o r Groups 1 & 2 combined. Fat L  Milk T  Fat T  Milk /D  Fat /D  Cullage  Plife  #Lact  .90  .58  . 56  .72  .60  .51  .51  .49  -  .54  . 57  .59  .72  .49  .50  . 47  .99  .47  .43  .98  .98  . 97  .44  .47  .98  .98  . 96  Fat L  .65  Milk T  .87  .75  . .77  . 87  . 96  -  Milk/D  .93  . 48  .71  .57  -  .79  .34  .34  . 33  Fat/D  .50  .95  .59  .74  .43  .34  .34  . 33  Cullage  .78  .75  .98  .97  .57  -  .57  -  1.0  .99  Plife  .78  .75  .98  .97  . 58  .57  1.0  . 99  # Lact  .76  .74  .98  .97  .55  .56  1.0  -  Fat T  a  Standard e r r o r s f o r g e n e t i c c o r r e l a t i o n s range between .014 and  b  A l l c o r r e l a t i o n s s i g n i f i c a n t l y d i f f e r e n t from zero  (P  <  .01)  1.0  .086.  -  - 104 -  lactation yields,  lifetime production  and l o n g e v i t y .  summary o f g e n e t i c c o r r e l a t i o n s i s i n T a b l e s c o m b i n e d and Group 2 s e t s o f d a t a ,  A  18 a n d 19 f o r  r e s p e c t i v e l y . The  g e n e t i c c o r r e l a t i o n s were o f g r e a t e s t i n t e r e s t b u t c a u t i o n in  i n t e r p r e t i n g these  c o r r e l a t i o n s i s warranted.  The  genetic  c o r r e l a t i o n s w e r e c a l c u l a t e d u s i n g h a l f - s i b a n a l y s i s and m u l t i p l i c a t i o n by a c o n s t a n t calculation.  Since  of four involved i n the  e r r o r s o f measurement  by t h i s f a c t o r , t h e s t a n d a r d  were a l s o  multiplied  e r r o r associated w i t h the genetic  c o r r e l a t i o n was a p p r o p r i a t e l y i n f l a t e d .  Thus, t h e magnitude  o f t h e c o r r e l a t i o n s h o u l d be j u d g e d i n r e l a t i o n t o i t s standard  e r r o r w h i c h i s m i n i m a l a n d a p p r o x i m a t e i n thi<s First  l a c t a t i o n milk y i e l d possessed strong  correlations with last lactation milk lifetime milk  study.  genetic  (.83 + . 0 4 ) , t o t a l  (.56 + .07) and m i l k p e r d a y o f p r o d u c t i v e  life  (.93 + . 0 2 ) ; and m o d e r a t e l y h i g h c o r r e l a t i o n s w i t h c u l l i n g (.44 + . 0 9 ) , p r o d u c t i v e l a c t a t i o n s completed  life  (.44 + .09) and number o f  (.41 + .09) f o r c o m b i n e d G r o u p s 1 and 2.  These c o r r e l a t i o n s d r o p p e d i n t h e Group 2 d a t a w i t h a increase i n the standard nature  errors  (Table  p e r day o f p r o d u c t i v e  life  c o r r e l a t i o n between f i r s t  of  similar  first  l i f e t i m e f a t and l o n g e v i t y , w i t h  c o r r e l a t i o n between f i r s t  corresponding  19). Estimates  and m a g n i t u d e w e r e a l s o o b s e r v e d b e t w e e n  lactation fat yield,  age  strongest  l a c t a t i o n f a t y i e l d and f a t y i e l d (.93 + .02) a n d t h e  poorest  l a c t a t i o n f a t y i e l d and t h e number o f  - 105 -  lactations  completed  (.44 + .09) i n G r o u p s 1 and 2 c o m b i n e d .  Almost i d e n t i c a l c o r r e l a t i o n s lactation  herd-year  were observed  deviation yields with  p r o d u c t i o n and l o n g e v i t y as t h o s e 305-day y i e l d s  lifetime  forfirst  lactation  w i t h l i f e t i m e p r o d u c t i o n and l o n g e v i t y  ( T a b l e s 18 a n d 1 9 ) . E s t i m a t e s o b t a i n e d somewhat l o w e r  for first  i n this  study a r e  t h a n t h e e s t i m a t e s r e p o r t e d by o t h e r  researchers  ( T a b l e 2 0) . The  genetic correlations  of t o t a l l i f e t i m e  w i t h l o n g e v i t y t r a i t s w e r e a l l a b o v e .96, i n d i c a t i n g the l o n g l i v e d  cows w e r e a l s o g e n e t i c a l l y  which i s supported  b y H a r g r o v e e t a l . (1969) who  estimates ranging from correlation essentially these  the high  .95 t o .97.  obtained genetic  suggests  they  m e a s u r e t h e same u n d e r l y i n g t r a i t s a n d one o f  t r a i t s w o u l d be adequate as a measure o f l o n g e v i t y . High g e n e t i c c o r r e l a t i o n s  with yields of y i e l d s  of f i r s t  lactation  p e r d a y (.93 + .02) and h i g h g e n e t i c  p e r day w i t h t o t a l l i f e t i m e y i e l d s  .74 + .05) s u g g e s t  yields  correlations  (.71 + .06 t o  t h a t y i e l d p e r d a y w o u l d be a b e t t e r  measure o f l i f e t i m e p r o d u c t i o n i n i n d i r e c t yields  that  producers,  Perfect positive  (1.0 + 0.0) among l o n g e v i t y t r a i t s  yields  selection,  since  p e r d a y h a v e r e l a t i v e l y h i g h e r g e n e t i c component  2 (h (h  2  = .21 t o .25) t h a n o t h e r m e a s u r e s o f l i f e t i m e p r o d u c t i o n 2 = .11 t o .12) a n d l o n g e v i t y (h = .09 t o . 1 0 ) .  - 106  An a n a l y s e s on  important  limitation  lifetime traits  -  i n i n t e r p r e t a t i o n of  i s the i n a b i l i t y  e f f e c t s o f s e l e c t i o n on c o r r e l a t i o n s .  clearly  A c c o r d i n g t o Brown  Turner  can  lead to estimates of genetic c o r r e l a t i o n s nearer  Two  s e l e c t i o n on one  to assess  and  in  (1968),  the  trait,  theoretically zero  s e l e c t e d p o p u l a t i o n compared t o u n s e l e c t e d p o p u l a t i o n . s e t s o f g e n e t i c c o r r e l a t i o n e s t i m a t e s gave a chance t o  l o o k a t t h e c h a n g e s i n g e n e t i c c o r r e l a t i o n s i n more s e l e c t e d m u l t i p l e l a c t a t i o n cows  (Group 2) c o m p a r e d t o e s t i m a t e s  on c o m b i n e d s i n g l e and m u l t i p l e l a c t a t i o n g r o u p s .  based  In general,  t h e drop i n the g e n e t i c c o r r e l a t i o n e s t i m a t e s from combined groups t o m u l t i p l e l a c t a t i o n group were h i g h e r w i t h involving f i r s t and  lactation production  l i f e t i m e p r o d u c t i o n and  l i f e t i m e p r o d u c t i o n and  ( m i l k and  l o n g e v i t y than  longevity traits.  fat yields)  those This  involving provides  some i n d i c a t i o n t h a t d a i r y m e n w e r e s e l e c t i n g f o r l a c t a t i o n m i l k and  fat yields.  I t was  those  first  not c l e a r l y  evident  w h e t h e r t h e y w e r e p u t t i n g more e m p h a s i s on m i l k y i e l d yield,  t h o u g h t h e r e was  of f i r s t  a s l i g h t r e d u c t i o n i n the  than f a t  heritability  l a c t a t i o n m i l k i n the m u l t i p l e l a c t a t i o n group  w e l l as a d r o p i n t h e g e n e t i c c o r r e l a t i o n b e t w e e n t h e traits;  a l s o no c h a n g e i n h e r i t a b i l i t y o f f a t y i e l d  some i n d i c a t i o n o f more s e l e c t i o n e m p h a s i s on f i r s t milk.  as  two  provide lactation  - 107 -  R e l a t i o n s h i p s of Expected Breeding Values f o r F i r s t L a c t a t i o n Y i e l d s w i t h L i f e t i m e P r o d u c t i o n and L o n g e v i t y  The e x p e c t e d  breeding values  (EBV) o f 138 s i r e s f o r  p r o d u c t i o n and l o n g e v i t y t r a i t s w e r e e s t i m a t e d u s i n g  least  s q u a r e s i r e c o n s t a n t s o b t a i n e d f r o m a n a l y s i s on c o m b i n e d f i r s t and m u l t i p l e l a c t a t i o n daughters Equation  16.  The r e s u l t s  according to  are presented  i n the Appendix  Table  The e s t i m a t e d EBV's showed l a r g e g e n e t i c d i f f e r e n c e s i n t h e transmitting a b i l i t i e s  of the sires  and  The EBV's f o r M i l k 1 r a n g e d  longevity traits.  f o r a l l the production from  -811 k g t o 843 k g ; F a t 1, -30 k g t o 36 k g ; M i l k T, -12607 k g to  12159 k g ; F a t T, -498 k g t o 475 k g ; M i l k / D ,  2.22 k g ; F a t / D , -.096 k g t o .093 k g ; and P l i f e , to  20.33 m o n t h s .  S i r e s were r a n k e d  and l o n g e v i t y .  relationship  b e t w e e n t h e EBV's f o r f i r s t  I n g e n e r a l , t h e r e was a lactation  l i f e t i m e p r o d u c t i o n and l o n g e v i t y .  By f o r m i n g  as i n T a b l e  appear.  for  -23.30 m o n t h s  differently for various  yield traits  22, i n t e r e s t i n g  -2.37 k g t o  results  direct  yields,  groups of b u l l  The a v e r a g e  EBV'  l i f e t i m e p r o d u c t i o n and l o n g e v i t y o f s i r e s w i t h a M i l k 1  EBV's o f 0.0 k g o r g r e a t e r was h i g h e r t h a n t h a t o f n e g a t i v e EBV b u l l s .  The a v e r a g e d i f f e r e n c e s w e r e 3853 k g  M i l k T, 116 kg F a t T, 1.34 k g M i l k / D , 5.2 month P l i f e .  remaining  Similarly,  .026 k g F a t / D and  s i r e s w i t h 0.0 k g o r b e t t e r f a t  EBV's h a d h i g h e r EBV's f o r l i f e t i m e p r o d u c t i o n and l o n g e v i t y than n e g a t i v e f a t r a t e d b u l l s w i t h average d i f f e r e n c e s of 4764 k g M i l k T, 210 k g F a t T,  .85 k g M i l k / D ,  .057 k g F a t / D  Table 22.  Differences i n average expected breeding values (EBV) f o r various groupings of b u l l s .  Average expected breeding values f o r l i f e t i m e production and longevity — — ——Milk T  Fat T  Milk/D  Fat/D  Plife  Number of Sires  1. EBV Milk 1  0.0  1827.12  55.67  .6243  .0127  2.56  72  2. EBV Milk 1  0.0  -2050.52  -59.93  -.7190  -.0135  -2.62  66  Av. Difference 1 vs 2  3852.64  115.60  1.3433  .0262  5.18  —  3. EBV Fat 1  0.0  2435.65  108.46  .4181  .0295  4.06  67  4. EBV Fat 1  0.0  -2328.46  -101.60  -.4299  -.0275  -3.67  71  Av. Difference 3 vs 4  4764.11  210.06  .8480  .0570  7.73  —  5. EBV Milk 1 and EBV Fat 1 0.0  2867.09  106.69  .7477  .0285  4.29  49  6. EBV Milk 1 o r EBV Fat 1 0.0  -1602.47  -58.14  -.4398  -.0154  -2.24  89  4469.56  164.83  1.1875  .0439  6.53  Av. Difference 5 vs 6  a  Units are i n kilogram except P l i f e which i s i n months.  —  - 109  and  7.7  months P l i f e .  EBV  and  0.0  -  B u l l s w i t h 0.0  kg F a t 1 EBV  o r b e t t e r had  EBV's f o r l i f e t i m e p r o d u c t i o n and EBV  M i l k 1 or Fat 1 b u l l s .  g r o u p s w e r e 447 0 k g , respectively,  Vleck  substantially  l o n g e v i t y than  higher  negative  Average d i f f e r e n c e between  k g , 1.19  kg,  f o r t h e above t r a i t s .  (1974) and Van of daughters  165  kg o r b e t t e r M i l k 1  .04  kg and  6.5  S c h a e f f e r and  (1964) a l s o f o u n d  these  months, Burnside  higher s u r v i v a l  rate  o f s i r e s w i t h p o s i t i v e m i l k p r o o f s compared t o  sires with negative milk proofs. P r o d u c t - m o m e n t c o r r e l a t i o n s among t h e EBV's f o r p r o d u c t i o n and  longevity obtained  values of s i r e s f o r Breed and  in this  C l a s s Averages  f a t o b t a i n e d from the Report  s t u d y and  (BCA's) o f m i l k  (1976) on D a i r y S i r e A p p r a i s a l ,  D i r e c t C o m p a r i s o n , A g r i c u l t u r e Canada i s p r e s e n t e d Table  23.  T h e r e was  BCA  data  f a t (r =  .91 and  set used i n t h i s  in  a g o o d a g r e e m e n t b e t w e e n t h e EBV's f o r  M i l k 1 and F a t 1 w i t h c o r r e s p o n d i n g and  breeding  s i r e p r o o f s f o r BCA  .92), which i s expected  study  because  i s a subset of t h a t used  R.O.P. f o r t h e i r  sire appraisal.  C o r r e l a t i o n s of  interest  study were t h o s e  i n v o l v i n g EBV's o f  in this  l a c t a t i o n m i l k and p r o d u c t i o n and All (P  f a t y i e l d s w i t h EBV's f o r  longevity traits  Milk/D  (.89)  and  first  lifetime  h i g h e s t c o r r e l a t i o n f o r M i l k 1 was  F a t 1, t h e h i g h e s t c o r r e l a t i o n  by  w h i c h a r e shown i n T a b l e  lowest with # Lact (.88)  (.33). was  the  particular  c o r r e l a t i o n 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 <. . 0 1 ) . The  milk  zero with  Similarly  w i t h Fat/D  for  and  24.  T a b l e 23.  Product-moment c o r r e l a t i o n s  0  between b r e e d i n g v a l u e s o f s i r e s f o r l i f e t i m e p r o d u c t i o n and l o n g e v i t y t r a i t s .  a  EBV  b  CDA BV Trait  BCAF Milk 1 Fat 1 M i l k HYl Fat HYl Milk L Fat L LLL Milk T Fat T Milk/D Fat/D Cullage Plife « Lact  .65 .91 .57 .91 .57 .68 .39 .39 .47 .38 .81 .42 .37 .37 .34  .59 .92 .58 .92 .47 .71 .35 .46 .54 .52 . 84 . 42 .42 .40  66 .o 65 75 45 37 43 38 89 48 36 36 33  e  • e i.o .54 .77 .33 . 47 .54 .56 .88 .41 .41 . 39 6 5  e  .66 .74 . 45 .36 .48 . 38 . 89 .48 . 36 .36 .33  54 76 32 47 54 56 88 41 41 39  a  B r e e d i n g v a l u e s o f s i r e s o b t a i n e d from Report  b  Expected  c  A l l correlations significantly  d  BCAM and BCAF r e p r e s e n t b r e e d - c l a s s - a v e r a g e  e  Values  !  .79 . 53 .75 . 68 . 84 . 58 . 67 . 67 . 64  .48 . 72 . 78 . 55 . 8C . 69 .69 . 67  hO  1  .48 .47 .38 .34 . 46 . 46 .39  .93 . 58 . 57 . 98 . 98 . 97  !  .49 . 66 .97 .97 . 97  .60 . 44 .44 .42  .51 .51 .50  1.0 .99  .99  (1976), A g r i c u l t u r e Canada,  b r e e d i n g v a l u e s c a l c u l a t e d u s i n g e q u a t i o n 16. different  > .995 have been rounded t o 1.0.  f r o . zero  (P <  ^  m i l k and f a t , r e s p e c t i v e l y .  ^  d  e  f  i  n  e  d  p  a  g  e  s  2 8  ,  2  9  a  n  d  T a b  le4,  Table 24.  Product-moment c o r r e l a t i o n s between expected breeding values (EBV) f o r f i r s t l a c t a t i o n y i e l d s , l i f e t i m e production and longevity.  L i f e t i m e Production , and Longevity T r a i t s  F i r s t Lactation Yields Milk 1 Fat  Milk L  .75  .54  Fat L  .45  .77  Milk T  .48  .47  Fat T  . 38  .54  Milk/D  .89  .56  Fat/D  .48  .88  Cullage  .36  .41  Plife  .36  .41  # Lact  .33  .39  a  A l l c o r r e l a t i o n s s i g n i f i c a n t l y d i f f e r e n t from zero (P  b  T r a i t s are defined i n pages 28,  29 and Table 4.  .01).  - 112  lowest w i t h # Lact lower for  (.39).  -  These c o r r e l a t i o n s are  than the corresponding  these  traits  (Table 18).  daughters f o r each s i r e ,  genetic c o r r e l a t i o n s obtained Due  to the  fat  EBV's on  l a r g e numbers o f  t h e c o r r e l a t i o n s o f EBV's  l a r g e l y genetic plus the e r r o r s of T a b l e 25  shows p r e d i c t i o n e q u a t i o n s  l i f e t i m e production  The  s i r e EBV  for f i r s t  are  estimation.  and  of m i l k  and  l o n g e v i t y EBV's,  t h e p e r c e n t a g e o f v a r i a t i o n e x p l a i n e d by equation.  slightly  each  and  regression  l a c t a t i o n m i l k and  fat  y i e l d s a r e v e r y g o o d p r e d i c t o r s o f EBV's f o r m i l k and y i e l d s per  day,  r e s p e c t i v e l y accounting  f o r 73%  fat  of the  total  v a r i a t i o n s i n each case.  Adding a second v a r i a b l e , f i r s t  lactation fat with f i r s t  l a c t a t i o n m i l k or v i c e versa d i d  improve the p r e d i c t i v e v a l u e l a c t a t i o n m i l k and  22%  traits  First  f a t y i e l d EBV's a r e s e p a r a t e l y  g o o d p r e d i c t o r s o f EBV and  of the equation.  unexplained  a small extra reduction  variation.  equally  f o r l i f e t i m e milk, accounting  o f t h e t o t a l v a r i a t i o n , r e s p e c t i v e l y , and provides  First  (4% and  not  for  23%  using both  5%)  l a c t a t i o n m i l k i s not  the  i n the as  good  2 a p r e d i c t o r of t o t a l first  lifetime fat yield 2  lactation fat yield  milk after f i r s t  (R  = 29%),  and  l a c t a t i o n f a t does not  of the p r e d i c t i o n .  (R  = 1 4 % ) , as adding f i r s t  improve the  the lactation  efficiency  First lactation fat is a slightly 2 p r e d i c t o r o f t h e l e n g t h o f p r o d u c t i v e l i f e (R = .17) 2 f i r s t l a c t a t i o n m i l k (R = . 1 3 ) .  better than  Table 25.  Trait  Intercept  EBV M i l k T =  EBV F a t T- =  Ebv Milk/D =  EBV Fat/D =  EBV P l i f e  Regressions o f expected breeding value . (EBV) milk and/or expected breeding value f a t on expected breeding values f o r l i f e t i m e production and longevity.  =  22.78 -10.25 11.26  1.60 .6192 .76  .0053 .0170 .0050  b  (EBV M i l k 1)  + + +  7.25  +  .2297  +  .0296  +  .0024  +  .0025  .00049 .00027 .00017  .1316 .0879 .1088  x  4.48  +  b  2  (EBV Fat 1)  + +  178.06 104.81  23 22 27  + +  8.07 7.59  14 29 29  .0386 .0022  78 32 78  + +  .0026 .0029  23 78 79  + +  ,2786 .2073  13 17 18  .000056 .000021  +  .0098  +  .0044  Variation „ Explained (R )  - 114 -  The  regression coefficients  k g d i f f e r e n c e i n EBV o f s i r e  i n d i c a t e t h a t f o r each  forfirst  lactation milk,  there  was a d i f f e r e n c e o f more t h a n 7 k g i n a v e r a g e EBV f o r lifetime milk; fat,  and f o r e a c h k g d i f f e r e n c e i n f i r s t  lactation  t h e r e was a d i f f e r e n c e o f more t h a n 8 k g i n a v e r a g e EBV  for  lifetime fat.  for  first  F o r e a c h 1000 k g d i f f e r e n c e i n EBV o f s i r e  l a c t a t i o n m i l k t h e r e was a d i f f e r e n c e o f o v e r  9 months i n t h e l e n g t h  of productive, l i f e .  - 115  -  CONCLUSIONS  Genetic p r o d u c t i o n and  and  environmental  Estimates  heritabilities  and  estimated  and  o f t h e i n d i v i d u a l t r a i t s were o b t a i n e d ,  c a n be p r a c t i s e d .  The  no  effective  p r o g r a m was  f u r t h e r e v a l u a t e d by  among t h e s e  traits.  inclusion  estimation  Additionally  v a l u e o f s i r e p r o o f s f o r l i f e t i m e p r o d u c t i o n and s i m i l a r to those  since  selection  s u i t a b i l i t y of a t r a i t for  of g e n e t i c c o r r e l a t i o n s  traits,  in this  o f g e n e t i c components o f v a r i a n c e  i n the absence o f g e n e t i c v a r i a t i o n  in a selection  lifetime  l o n g e v i t y o f H o l s t e i n cows i n C a n a d i a n R e c o r d  o f Performance herds were e v a l u a t e d study.  parameters of  the  longevity  f o r m i l k and/or f a t y i e l d s  was  examined. T h i s r e p o r t i s now p o i n t s a r i s i n g from t h i s 1)  The  concluded  c o e f f i c i e n t s of v a r i a t i o n  s t u d i e s due  to  o f r e s t r i c t i o n s w h i c h w e r e i m p o s e d on t h e i r d a t a ,  as a r e q u i r e d number o f c o m p l e t e d l a c t a t i o n o r a age,  of  l o n g e v i t y t r a i t s d e r i v e d were r e l a t i v e l y  f r e e f r o m t h e b i a s e s f o u n d i n some p r e v i o u s nature  salient  research.  means and  l i f e t i m e p r o d u c t i o n and  w i t h t h e most  and  the  such  specific  b e c a u s e a l l cows w e r e known t o h a v e b e e n c u l l e d w i t h i n  the p e r i o d s t u d i e d . 2) factor it  H e r d e f f e c t was  affecting variation  a c c o u n t e d f o r b e t w e e n 5%  f o u n d t o be t h e m o s t  i n p r o d u c t i o n and (for Cullage)  and  important  longevity t r a i t s ; 37.6%  (for Fat/D).  - 116  Herd e f f e c t s f o r t o t a l lower  -  l i f e t i m e y i e l d s and  i n magnitude compared t o f i r s t  H e r d e f f e c t r e f l e c t e d any  lactation  from t h i s d a t a .  t h a t an i n t e r a c t i o n among h e r d ,  year  Due and  and  the g e n e t i c p a r a m e t e r s were e s t i m a t e d  3)  environmental  I n d i v i d u a l environmental  number o f h e r d s i n c l u d e d i n t h i s s t u d y  herd-year-season  yields.  g e n e t i c as w e l l as t h e  d i f f e r e n c e s between h e r d s . c o u l d n o t be e v a l u a t e d  l o n g e v i t y were  to the  effects large  also, recognising  season might  on t h e b a s i s o f w i t h i n  subclasses.  Yearly trends  in first  l a c t a t i o n m i l k and  y i e l d s were upward i n t h i s p o p u l a t i o n w h i c h r e f l e c t e d j o i n t e f f e c t s o f i m p r o v e d n u t r i t i o n and mainly  t o t h e e x t e n s i v e use  i n s e m i n a t i o n , . T h e r e was  completed, i n d i c a t i n g  the  genetic progress  of proven b u l l s through  life  and  due  artificial  i n t h e number o f l a c t a t i o n s  s l i g h t l y increased turnover  I t i s concluded  t h a t the year  showing y e a r l y t r e n d .  T h i s i s because the  production  i n c r e a s e i n the  rates  during  e f f e c t should  i n c l u d e d i n an a n a l y s i s f o r h e r i t a b i l i t y e s t i m a t e s  l e a d s t o an  fat  a s l i g h t tendency f o r a r e d u c t i o n i n  the l e n g t h of p r o d u c t i v e  the p e r i o d .  exist,  be  using  data  i n c r e a s e i n mean  s i r e component o f  variance at a r a t e s l i g h t l y f a s t e r than the i n c r e a s e i n residual variance,  thus, i n c r e a s i n g the h e r i t a b i l i t y  f r o m p a t e r n a l h a l f - s i b c o r r e l a t i o n s (Van V l e c k , the omission  of the year  c o n f o u n d i n g between year  estimated  1966).  Also  e f f e c t from the model might l e a d and  s i r e e f f e c t s and  thus could  to bias  - 117 -  the i n t r a c l a s s c o r r e l a t i o n upward. 4) to  Cows which f i r s t f r e s h e n e d d u r i n g September  February produced more m i l k and f a t i n t h e f i r s t  lactation  than those w h i c h f r e s h e n e d f i r s t d u r i n g March t o August; t h i s trend i s s i m i l a r t o the f i n d i n g s of other studies i n the n o r t h e r n hemisphere.  Hov/ever, l o n g e v i t y t r a i t s were n o t  s i g n i f i c a n t l y a f f e c t e d by t h e season o f f i r s t c a l v i n g . to presence  Due  o f a year by season i n t e r a c t i o n f o r some o f t h e  t r a i t s under study and s i n c e herds might d i f f e r i n s e a s o n a l e f f e c t s , a herd-year-season  c l a s s i f i c a t i o n was used t o e s t i m a t e  s i r e components f r e e from t h e independent and j o i n t of these  effects  factors. 5)  Cows w h i c h f i r s t f r e s h e n e d a t an o l d e r age  produced more m i l k and f a t d u r i n g t h e i r l i f e t i m e and a l s o p e r day o f p r o d u c t i v e l i f e , compared t o cows f i r s t c a l v i n g younger. On t h e o t h e r hand, younger c a l v e r s completed more l a c t a t i o n s and s t a y e d l o n g e r i n t h e herd.  T h i s may be due t o t h e reason  t h a t t h e l a t e c a l v e r s , h a v i n g h i g h e r l a c t a t i o n y i e l d s , have l o n g e r c a l v i n g i n t e r v a l s and might have been c u l l e d more f r e q u e n t l y f o r b r e e d i n g problems, thus r e d u c i n g t h e i r l e n g t h of p r o d u c t i v e 6)  life. High producers  i n the f i r s t lactation within  the herd had l o n g e r c a l v i n g i n t e r v a l s than t h e i r herdmates producing l e s s milk.  Higher t o t a l l i f e t i m e p r o d u c t i o n o f  cows w i t h l o n g e r c a l v i n g i n t e r v a l s was due t o more days i n p r o d u c t i o n s i n c e p r o d u c t i o n perday o f l i f e was n e g a t i v e l y  - 118 -  correlated with calving interval.  I t appears t h a t  consider production i n the current l a c t a t i o n , of l a c t a t i o n  farmers  irrespective  l e n g t h , when m a k i n g c u l l i n g d e c i s i o n s and a l s o  t h a t t h e y a l l o w more c h a n c e s f o r c o n c e p t i o n t o o c c u r y i e l d i n g cows l a t e r i n l i f e  than they permit  i n high  i n earlier  lactations. 7)  Genetic  t r e n d s i n p r o d u c t i o n and l o n g e v i t y  t r a i t s w e r e p o s i t i v e among t h e d a u g h t e r s 1946  through  first  o f s i r e s born  1960, though t h e r a t e o f p r o g r e s s  l a c t a t i o n m i l k and f a t y i e l d s were lower  during  per year i n than  other  estimates r e c e n t l y reported f o rd i f f e r e n t H o l s t e i n populations i n U.S. and C a n a d a .  These t r e n d s j u s t i f y t h e use o f s i r e  groups i n s i r e e v a l u a t i o n s as w e l l as i n g e n e t i c parameter e s t i m a t e s f o r p r o d u c t i o n and l o n g e v i t y t r a i t s .  Grouping  by  year o f s i r e ' s b i r t h defines s e v e r a l sub-population o f s i r e s w i t h d i f f e r e n t means a n d a l s o r e m o v e s b i a s due t o g e n e t i c trends. 8)  The h e r i t a b i l i t y  estimates obtained  for first  l a c t a t i o n y i e l d s a r e w e l l w i t h i n t h e range o f l i t e r a t u r e values.  Due t o t h e h i g h e c o n o m i c v a l u e a n d m o d e r a t e  heritability of f i r s t  lactation milk y i e l d ,  be m e a s u r e d e a r l y i n a n a n i m a l ' s advised to continue selecting yield.  This w i l l  life,  d a i r y m e n w o u l d be  f o r high f i r s t  lead t o simultaneous  and s i n c e i t c a n  lactation  milk  p o s i t i v e changes i n  l i f e t i m e p r o d u c t i o n and l o n g e v i t y t r a i t s .  - 119  9)  -  Selection for total  l i f e t i m e production  l o n g e v i t y m e a s u r e d e i t h e r as l e n g t h o f p r o d u c t i v e as number o f l a c t a t i o n s , w o u l d n o t be low h e r i t a b i l i t y these  of these  r e s u l t s i s t h a t any  traits.  life  e f f e c t i v e due  achieved  by  overall  improvements  other environmental  factors  w h i c h e x e r t an i n f l u e n c e on t h e w e a r a b i l i t y o f cows.  However,  w i t h i n t h e s e m a j o r i n f l u e n c e s , t h e cows w h i c h r e m a i n i n the herd w i l l thus w i l l  the  A f u r t h e r i m p l i c a t i o n of  o n l y be  i n n u t r i t i o n a l , p a t h o l o g i c a l and  or  to  marked improvement i n the  l o n g e v i t y o f d a i r y c a t t l e can  and  longest  n a t u r a l l y l e a v e t h e l a r g e s t number o f o f f s p r i n g  c r e a t i n g the opportunity  f o r automatic  selection for  longevity. 10)  S e l e c t i o n on p e r f o r m a n c e t r a i t s o f  first  l a c t a t i o n seems m o s t d e s i r a b l e f o r c h a n g i n g l i f e t i m e s i n c e s e l e c t i o n on  lifetime traits  postponement of s e l e c t i o n u n t i l  production  i s not p r a c t i c a l .  The  i n f o r m a t i o n i s a v a i l a b l e on  l i f e t i m e t r a i t s would g r e a t l y increase the costs of p o t e n t i a l replacement stocks u n t i l p r o g e n y a r e a v a i l a b l e , and per year.  records  life  F o r t u n a t e l y , the g e n e t i c c o r r e l a t i o n s of  a r e p o s i t i v e and  heritability  of f i r s t  than the h e r i t a b i l i t y for  on t h e dam  thus reduce the genetic  l a c t a t i o n m i l k w i t h l i f e t i m e m i l k and high ranging  m i l k p e r day  f r o m .56  lactation milk y i e l d of l i f e t i m e milk  l i f e t i m e milk using f i r s t  maintaining  to (.22)  .93.  or  sire's  progress first of  productive Since  i s much  the  higher  (.11), i n d i r e c t s e l e c t i o n  l a c t a t i o n m i l k as t h e s e l e c t i o n  - 120 -  c r i t e r i o n w o u l d be a b o u t 79% a s a c c u r a t e selection  f o r lifetime milk yield-  f o r m i l k p e r day o f p r o d u c t i v e  having  genetic correlation 11)  an e s t i m a t e  life  of  first  as d i r e c t  selection  due t o t h e v e r y  high  (.93) b e t w e e n t h e two t r a i t s .  The h i g h e r g e n e t i c c o r r e l a t i o n  l a c t a t i o n m i l k and t o t a l l i f e t i m e m i l k t h a t between f i r s t  selection  (.21) a s t h a t o f  l a c t a t i o n m i l k w o u l d be 9 5 % as a c c u r a t e f o r m i l k p e r day o f p r o d u c t i v e  direct  Indirect  life  h e r i t a b i l i t y o f s i m i l a r magnitude  as  between  last  (.87) c o m p a r e d w i t h  l a c t a t i o n m i l k and t o t a l l i f e t i m e  milk  (.56) s u g g e s t s t h a t f a r m e r s s h o u l d p a y a t t e n t i o n t o y i e l d in  the l a c t a t i o n  immediately  preceding  when m a k i n g a  culling decision. 12)  The r e s u l t s  o f t h i s study  l e n d no  whatsoever t o suggestions  that selection  lactation milk y i e l d w i l l  reduce the working l i f e  cattle;  r a t h e r they  point clearly  support  b a s e d on  first of dairy  i n the opposite  direction.  I n t h i s p o p u l a t i o n o f H o l s t e i n cows t h e c o r r e l a t i o n first  l a c t a t i o n m i l k y i e l d and t h a t i n t h e l a s t  ( b e a r i n g i n m i n d t h a t we a r e c o r r e l a t i n g with i t s e l f  lactation  the f i r s t  lactation  i n o n e - t h i r d o f t h e d a t a ) i s .83, w h e r e a s b e t w e e n  h e i f e r m i l k y i e l d and l e n g t h o f p r o d u c t i v e These r e s u l t s  indicate  production would r e s u l t produce w e l l  life,  i t i s .44.  that the evaluation of A . I . s i r e s  the b a s i s of t h e i r daughters f i r s t  will  between  lactation  on  l e v e l of milk  i n p r o v e n b u l l s whose d a u g h t e r s  i n later life  and r e m a i n i n t h e h e r d  longer.  - 121  13)  This study  has  -  shown t h a t t h e r e  r e l a t i o n s h i p between the b r e e d i n g l a c t a t i o n m i l k and  total  values  lifetime milk  is a  of s i r e  (.46).  close  for  first  T h i s means  t h a t the d i f f e r e n c e s between s i r e s i n t h e i r h e i f e r progeny test w i l l  be m a i n t a i n e d  production;  i n t h e i r daughter's t o t a l  t h i s combines l e n g t h of p r o d u c t i v e  l e v e l of production per difference  i n the breeding  m i l k , t h e r e was breeding  lactation.  value  value  For each  of s i r e  life  f o r l i f e t i m e m i l k ; and value  for f i r s t  a d i f f e r e n c e o f o v e r 9 months i n t h e b r e e d i n g  the  length of productive  i n d i c a t e t h a t the  rank high f o r m i l k  achieved  value  which  proof.  and  lactation yields  Because of  the g e n e t i c c o r r e l a t i o n s obtained selection intensity  this  gave a  for milk  production lifetime  T h e s e c o r r e l a t i o n s w o u l d a l s o be d e p e n d e n t on  i n t e n s i t y of i n v o l u n t a r y c u l l i n g production.  with  l o n g e v i t y a r i s e both from p l e i o t r o p y  the genetic a s s o c i a t i o n of m i l k production w i t h  traits.  for  and  by u s i n g b u l l s  from s e l e c t i o n f o r m i l k p r o d u c t i o n .  measure o f b o t h the  there  These f i n d i n g s c l e a r l y  c o r r e l a t i o n s of f i r s t  lifetime production  and  kg  improvement i n l i f e t i m e p r o d u c t i o n  l o n g e v i t y o f d a u g h t e r s can be  confounding,  the  lactation milk  was  and  lactation  f o r e a c h 1000  for first  life.  with  kilogram  a d i f f e r e n c e o f more t h a n 7 kg i n  difference i n breeding  Genetic  lifetime  for traits  other than  I f intense s e l e c t i o n for milk production  a sharp i n c r e a s e i n the r a t e of i n v o l u n t a r y c u l l i n g ,  the milk causes  the  - 122  -  i n t e n s i t y of s e l e c t i o n f o r p r o d u c t i o n c o r r e l a t i o n between m i l k p r o d u c t i o n h e r d l i f e w o u l d be  and  and  a l s o the  the  length  difficult  other  i n which there  i s no  culling  yield.  production exert  their  correlation  f r e e from s e l e c t i o n e f f e c t s .  i f p r a c t i s e d on  a few  for milk  give  S e l e c t i o n f o r long productive only  for milk  f a c t o r s s u c h as u d d e r b r e a k d o w n , w h i c h  e f f e c t s as l o w m i l k p r o d u c t i o n , w i l l estimates  generation  to o b t a i n these c o r r e l a t i o n s  f r e e from confounding w i t h s e l e c t i o n p r e s s u r e  and  of  expected t o decrease i n the next  However, i t w o u l d be  Populations  genetic  life will  be  s i r e s of young A . I . b u l l s ,  since  s i r e s a r e needed t o c o n t r i b u t e t o the n e x t  o f y o u n g s i r e s , and  generation  be m e a s u r e d e a r l y i n l i f e  on e a r l y p r o d u c t i v e  and  are  reproductive  l a c t a t i o n , and  found.  performances  s u c h as t h e p e r c e n t a g e s o f a s i r e ' s d a u g h t e r s n o t their first  only  only i f g e n e t i c a l l y variable predictors  o f l o n g e v i t y w h i c h can Information  feasible  completing  the percentages of a s i r e ' s  yearli  daughters f a i l i n g  to conceive  daughter's l i f e .  T h e s e c o u l d be v a l u a b l e i f s i g n i f i c a n t  d i f f e r e n c e s e x i s t i n these for  c o u l d be m e a s u r e d e a r l y i n  traits  example, have h i g h p r o d u c t i o n  percentages of daughters c u l l e d reproductive  and  proofs  and  S i r e s which,  relatively  f o r low p r o d u c t i o n ,  udder problems, should  percentage of p r o f i t a b l e progeny. c o n s i d e r a t i o n as  among b u l l s .  have a  These would  s i r e s o f young A . I . b u l l s .  the  low  or e a r l y  high merit  Thus, f u t u r e  - 123  research  on t h i s  -  s u b j e c t s h o u l d be  r e c o r d i n g i n f o r m a t i o n and e a r l y i n a cow's l i f e  d i r e c t e d towards  e v a l u a t i n g the t r a i t s  expressed  t o g e t h e r w i t h an e s t i m a t i o n o f  relations with lifetime production  and  longevity.  their  - 124 -  BIBLIOGRAPHY  Ahunu, B.K. 1 9 7 8 . G e n e t i c and e n v i r o n m e n t a l p a r a m e t e r s o f m i l k p r o t e i n y i e l d s i n H o l s t e i n s . M.Sc. T h e s i s , U n i v e r s i t y o f B r i t i s h Columbia, Vancouver. Allaire,  F.R. and C.R. H e n d e r s o n . 1966. S e l e c t i o n p r a c t i s e d among d a i r y cows. I I . T o t a l p r o d u c t i o n o v e r a sequence o f l a c t a t i o n s . J . D a i r y S c i . 49: 1435-1440.  Allaire,  F.R., H.E. S t e r w e r f and T.M. L u d w i c k . 1 9 7 6 . V a r i a t i o n s i n r e m o v a l r e a s o n s and c u l l i n g r a t e s w i t h age f o r d a i r y f e m a l e s . J . D a i r y S c i . 60:  254-267.  Amiel,  D.K. and E.W. M o o d i e . 1973. D a i r y herd wastage i n south e a s t e r n Queensland. Australian Veterinary J o u r n a l 4 9 : 69-73.  A n d r u s , D.F., A . E . Freeman a n d B.R. E a s t w o o d . d i s t r i b u t i o n and h e r d l i f e e x p e c t a n c y herds. J . D a i r y S c i . 53: 764-771. Annis,  1970. Age i n Iowa d a i r y  D . J . , R.E. E r b and W.R. W i n t e r s . 1959. I n f l u e n c e o f month and s e a s o n o f c a l v i n g on y i e l d s o f m i l k and fat. Washington A g r . Exp. S t a . , B u l l . 606.  Bakels,  F. 1 9 5 9 . R e l a t i o n s between m i l k y i e l d and l e n g t h of u s e f u l l i f e i n an A l l a n herd. Animal Breeding A b s t r a c t . 2 7 : No. 4, A b s t r . 1 7 5 4 .  Barker,  J . S . F . and A. R o b e r t s o n . 1 9 6 6 . G e n e t i c and phenotypic parameters f o r the f i r s t three l a c t a t i o n s i n F r i e s i a n cows. Anim. P r o d . 8: 2 2 1 - 2 4 0 .  Barr,  G.R. and L.D. Van V l e c k . 1 9 6 3 . R e g r e s s i o n and c o r r e l a t i o n among c o n s e c u t i v e and n o n c o n s e c u t i v e lactation records. J . D a i r y S c i . (Abstr.) 46: 628.  Bereskin,  Batra,  B. and A . E . Freeman. 1 9 6 5 . G e n e t i c and e n v i r o n m e n t a l factors i n dairy sire evaluation. I. E f f e c t s of h e r d s , months and y e a r - s e a s o n s on v a r i a n c e among l a c t a t i o n r e c o r d s ; r e p e a t a b i l i t y and h e r i t a b i l i t y . J. D a i r y S c i . 48:347-351.  T.R., E.B. B u r n s i d e and M.G. Freeman. 1971. Canadian d a i r y cow d i s p o s a l s . I I . E f f e c t o f h e r d s i z e and p r o d u c t i o n l e v e l on d a i r y d i s p o s a l p a t t e r n s . Can. J . Anim. S c i . 5 1 : 8 5 - 8 7 .  - 125 -  B e y n o n , V.H. 1978. The d i s p o s a l o f d a i r y cows i n E n g l a n d and W a l e s 1976-77. E x e t e r , U.K. A g r i c u l t u r a l Economics u n i t , E x e t e r University... Animal Breeding A b s t r a c t (1979). V o l . 47. A b s t r . ' 6 0 2 . B l a n c h a r t , R.P., A.E. Freeman and P.W. S p i k e . 1966. Variation i n lactation yield of milk constituents. J . D a i r y S c i . 49: 1 2 4 9 - 1 2 5 3 . B r a d f o r d , G.E. a n d L.D. V a n V l e c k . 1964. H e r i t a b i l i t y i n relation to selection differential i n cattle. G e n e t i c s 49: 819-827. B r o w n , G.H. a n d H.N. T u r n e r . 1968. R e s p o n s e t o s e l e c t i o n i n A u s t r a l i a n M e r i n o sheep. I I . E s t i m a t e s o f p h n e o t y p i c a n d g e n e t i c p a r a m e t e r s f o r some p r o d u c t i o n t r a i t s i n M e r i n o ewes and an a n a l y s i s o f t h e p o s s i b l e e f f e c t s o f s e l e c t i o n on them. Aust. J . Agr. R e s . 19: 303-322. B u r n s i d e , E.B. and J . E . L e g a t e s . 1967. E s t i m a t i o n o f g e n e t i c trends i n dairy c a t t l e populations. J . D a i r y S c i . 50: 1448-1457. B u r n s i d e , E.B. a n d J.W. W i l t o n . 1970. A n a t o m i c a l t r a i t s as t h e y r e l a t e t o p r o d u c t i v e u t i l i t y . J . Dairy S c i . 53: 837-846. B u r n s i d e , E.B., S.B. K o w a l c h u k , D.B. L a m b r o u g h t o n a n d N.M. M a c L e o d . 1 9 7 1 . C a n a d i a n d a i r y cow d i s p o s a l s . I. D i f f e r e n c e s b e t w e e n b r e e d s , l a c t a t i o n numbers and s e a s o n s . Can. J . Anim. S c i . 51: 75-83. E v a n s , D.L., C. B r a n t o n a n d B.R. F a r t h i n g . 1964. H e r i t a b i l i t y e s t i m a t e s and i n t e r r e l a t i o n s h i p s among p r o d u c t i o n p e r day o f p r o d u c t i v e l i f e , l o n g e v i t y , b r e e d i n g e f f i c i e n c y and type i n a herd o f H o l s t e i n cows. J . D a i r y S c i . ( A b s t r . ) 47: 699. E v e r e t t , R.W., D.V. A r m s t r o n g a n d L . J . B o y d . 1966. G e n e t i c r e l a t i o n s h i p between p r o d u c t i o n and b r e e d i n g efficiency. J . D a i r y S c i . 49: 879-886. E v e r e t t , R.W., J . F . Keown a n d E.E. C l a p p . 1976. R e l a t i o n s h i p s among t y p e , p r o d u c t i o n and s t a y a b i l i t y i n H o l s t e i n cattle. J . D a i r y S c i . 59: 1505-1510. Postage,  O.T. a n d H.K. Welch:. 1960. E f f e c t o f c e r t a i n e n v i r o n m e n t a l f a c t o r s upon m i l k p r o d u c t i o n i n Georgia. J . D a i r y S c i . ( A b s t r . ) 4 3 : 442.  - 126  -  F r a z e r , W.J. 1930. D a i r y Farming. New York, N.Y.  John Wiley  and  Sons,  Freeman, A.E. 1960. Genetic r e l a t i o n s h i p among the f i r s t three l a c t a t i o n s of H o l s t e i n cows. J . D a i r y S c i . (Abstr.) 43: 87 6. Gaalaas, R.F. and R.D. Plowman. 1963. R e l a t i o n s h i p between l o n g e v i t y and p r o d u c t i o n i n H o l s t e i n - F r i e s i a n c a t t l e . J . D a i r y S c i . 46: 27-33. Gacula,  M.C. J r . , S.N. Gaunt and R.A. J r . Damon. 1968. Genetic and environmental parameters of m i l k c o n s t i t u e n t s f o r f i v e breeds. I. E f f e c t of herd, year, season and age of cow. J . D a i r y S c i . 51: 428-437.  Gacula,  M.C. J r . , S.N. Gaunt and R.A. J r . Damon. 1968. Genetic and environmental parameters of m i l k c o n s t i t u e n t s f o r f i v e breeds. I I . Some g e n e t i c parameters. J . D a i r y S c i . 51: 438-443.  Gaunt, S.N., M.C. J r . Gacula and A.R. Corwin. 1966. V a r i a t i o n i n m i l k c o n s t i t u e n t s and m i l k y i e l d f o r f i v e breeds of d a i r y c a t t l e . 17th I n t e r n . D a i r y Congr. Sec. A: 1, p.29. Gill,  G.S. and F.R. A l l a i r e . 1976. Genetic and phenotypic parameters f o r a p r o f i t f u n c t i o n and s e l e c t i o n method f o r o p t i m i z i n g p r o f i t i n d a i r y c a t t l e . J . D a i r y S c i . 59: 1325-1332.  Gilmore,  L.O. D a i r y C a t t l e Breeding. J.P. L i p p i n c o t t Company, New York, N.Y. 1952.  Hargrove, G.L. and J.E. Legates. 1971. Biases i n d a i r y s i r e e v a l u a t i o n a t t r i b u t a b l e t o g e n e t i c t r e n d and female s e l e c t i o n . J . D a i r y S c i . 54: 1041-1051. Hargrove, G.L., J . J . S a l a z a r and J.E. Legates. 1969. R e l a t i o n s h i p among f i r s t - l a c t a t i o n and l i f e t i m e measurements i n a d a i r y p o p u l a t i o n . J . Dairy S c i . 52: 651-656. Harvey, W.R. 197 6. Mixed model l e a s t - s q u a r e s and maximum l i k e l i h o o d computer program (LSML 76). Ohio S t a t e U n i v e r s i t y , Columbus, Ohio. Harvey, W.R. 1968. Least-squares and maximum l i k e l i h o o d g e n e r a l purpose computer program (LSMLGP). Ohio State U n i v e r s i t y , Columbus, Ohio.  - 127 -  H a r v e y , W.R. 197 0. E s t i m a t i o n o f v a r i a n c e and c o v a r i a n c e components i n m i x e d model. B i o m e t r i c s 26: 485-504. Henderson, C R . 1975. Comparison o f a l t e r n a t i v e s i r e e v a l u a t i o n methods. J . A n i m . S c i . 4 1 : 760-770. H i c k m a n , C.G. and C R . H e n d e r s o n . 1955. Components o f t h e r e l a t i o n s h i p b e t w e e n l e v e l o f p r o d u c t i o n and rate of maturity i n dairy cattle. J . Dairy S c i . 38: 883-890. H i n k s , C.J.M. 1966. S e l e c t i o n p r a c t i c e s i n d a i r y h e r d s . II. Selection patterns i n the later lactations. A n i m . P r o d . 8: 481-488. H i n t z , R.L., R.W. E v e r e t t and L.D. V a n V l e c k . 1978. E s t i m a t i o n o f g e n e t i c t r e n d s f r o m cow a n d s i r e evaluations. J . D a i r y S c i . 61: 607-613. J o h a n s s o n , I . 1962. G e n e t i c a s p e c t s o f d a i r y breeding. O l i v e r and Boyd, E d i n b u r g h .  cattle  J o h a n s s o n , I . 1955. The f i r s t l a c t a t i o n y i e l d a s a b a s i s f o r s e l e c t i o n as compared w i t h t h e second and t h i r d lactation. P r o c . B r i t i s h S o c . A n i m a l P r o d . 1 9 5 5 : 102, J o h a n s s o n , I . and A. H a n s s o n . 1940. C a u s e s o f v a r i a t i o n i n m i l k and b u t t e r f a t y i e l d o f d a i r y cows. K u n g l . L a n t k r . T i d s k r i f t , 79: 61-2. J o h n s o n , L.A. a n d E . L . C o r l e y . 1 9 6 1 . H e r i t a b i l i t y and r e p e a t a b i l i t y o f f i r s t , second, t h i r d and f o u r t h r e c o r d s o f v a r y i n g d u r a t i o n i n Brown S w i s s c a t t l e . J . D a i r y S c i . 44: 5 3 5 - 5 4 1 . J o h n s t o n , J . E . , C. L e w i s , E . J . S t o n e and C. B r a n t o n . 1956. The i n f l u e n c e o f s e a s o n o f f r e s h e n i n g o n p r o d u c t i o n r e c o r d s o f J e r s e y a n d H o l s t e i n cows i n L u s i a n a . J . D a i r y S c i . ( A b s t r . ) 39: 9 3 3 . K e n n e d y , B.W. a n d J . E . M o x l e y . 1975. G e n e t i c t r e n d s among a r t i f i c i a l l y b r e d H o l s t e i n s i n Quebec. J . D a i r y S c i . 58: 1 8 7 1 - 1 8 7 5 . Lamb, R . C a n d D.V. K o p l a n d . 1963. I n f l u e n c e o f age a t f i r s t c a l v i n g a n d c a l v i n g i n t e r v a l on p r o d u c t i o n p e r day o f l i f e and t o t a l l i f e t i m e p r o d u c t i o n . J . Dairy S c i . ( A b s t r . ) 46: 62 0. L a r s o n , C . J . , A.B. Chapman a n d L . E . C a s i d a . 1 9 5 1 . B u t t e r f a t p r o d u c t i o n p e r day o f l i f e as a c r i t e r i o n of s e l e c t i o n i n d a i r y c a t t l e . J . D a i r y S c i . 34: 1163-1169.  - 128 -  L a s l e y , J . F . 1963. G e n e t i c s o f L i v e s t o c k I m p r o v e m e n t . P r e n t i c e - H a l l , I n c . , E n g l e w o o d C l i f f s , New J e r s e y . Lee,  J . E . , O.T. F o s g a t e a n d J . L . Carmon. ' 1961. Some e f f e c t s o f c e r t a i n e n v i r o n m e n t a l and i n h e r i t e d i n f l u e n c e s upon m i l k and f a t p r o d u c t i o n i n d a i r y c a t t l e . J . D a i r y S c i . 44: 296-299.  Lin,  C.Y. and F.R. A l l a i r e . 1978. E f f i c i e n c y o f s e l e c t i o n on m i l k y i e l d t o a f i x e d a g e . J . D a i r y S c i . 6 1 : 489-496.  L u s h , J . L . 1945. A n i m a l B r e e d i n g P l a n s . S t a t e C o l l e g e P r e s s , Ames, Iowa.  3 r d ed.  Iowa  Mao, I . L . , E.B. B u r n s i d e , J.W. W i l t o n a n d M.G. F r e e m a n . 1974. Age-month a d j u s t m e n t o f C a n a d i a n d a i r y p r o d u c t i o n records. C a n . J . A n i m . S c i . 54: 5 3 3 - 5 4 1 . Martojo,  H., C. B r a n t o n , B.R. F a r t h i n g a n d D.L. E v a n s . 1 9 6 3 . F i r s t and second v e r s u s a l l l a c t a t i o n r e c o r d s f o r selecting dairy cattle i n hot climate. J . Dairy S c i . ( A b s t r . ) 46: 620.  M i l l e r , P.D. , W.E. L e n t z a n d C R . H e n d e r s o n . 1970. J o i n t i n f l u e n c e o f m o n t h a n d age o f c a l v i n g o n m i l k y i e l d o f H o l s t e i n cows i n t h e n o r t h e a s t e r n U n i t e d S t a t e s . J . D a i r y S c i . 53: 351-357. Miller,  P.D., W.E. L e n t z and C R . H e n d e r s o n . 1969. C o m p a r i s o n of c o n t e m p o r a r y d a u g h t e r s o f young and progeny tested dairy sires. J . D a i r y S c i . ( A b s t r . ) 5 2 : 926.  M i l l e r , P.D., L.D. V a n V l e c k and C R . H e n d e r s o n . 1967. R e l a t i o n s h i p s among h e r d l i f e , m i l k p r o d u c t i o n , and c a l v i n g i n t e r v a l . J . D a i r y S c i . 50: 1283-1287. M o l i n u e v o , H.A. a n d J . L . L u s h . 1964. R e p e a t a b i l i t y o f f i r s t , s e c o n d and t h i r d r e c o r d s f o r e s t i m a t i n g t h e b r e e d i n g v a l u e o f d a i r y cows. J . D a i r y S c i . 47: 890-893. O ' B l e n e s s , G.V. and L.D. V a n V l e c k . 1962. Reasons f o r d i s p o s a l o f d a i r y cows f r o m New Y o r k h e r d s . J . Dairy S c i . 45: 1087-1093. O'Conner, L.K. a n d J o h n H o d g e s . 1963. W a s t a g e a n d c u l l i n g i n d a i r y herds. A n i m . P r o d . 5: 165^173. Parker,  J . B . , N.D. B a y l e y , M.H. Fohrman a n d R.D. Plowman. 1960. Factors influencing dairy cattle longevity. J . D a i r y S c i . 4 3 : 4 01-4 09.  - 129 -  Plowman, R.D. and R.F. G a a l a a s . 1960. Heritability estimates of longevity i n H o l s t e i n - F r i e s i a n cattle. J . D a i r y S c i . ( A b s t r . ) 43: 877. P i r c h n e r , F. 1969. Population Genetics i n Animal W.H. Freeman & Co., San F r a n c i s c o .  Breeding.  P o w e l l , R.L. a n d A.E. F r e e m a n . 1974. G e n e t i c t r e n d estimators. J . D a i r y S c i . 57: 1067-1075. P u r i , T.R. a n d K.N. Sharma. 1965. P r e d i c t i o n o f l i f e t i m e p r o d u c t i o n on b a s i s o f f i r s t l a c t a t i o n y i e l d and age a t f i r s t c a l v i n g f o r s e l e c t i o n o f d a i r y c a t t l e . J . D a i r y S c i . 48: 462-467. R e n d e l , J.M. and A. R o b e r t s o n . 1950. Some a s p e c t s o f l o n g e v i t y i n d a i r y cows. Empire J . E x p t l . Agr. 18: 49-56. R e n d e l , J.M., A. R o b e r t s o n , A.A. A s k e r , S.S. K h i s h i n and M.T. Ragab. 1957. The i n h e r i t a n c e o f m i l k production characteristics. J . A g r . S c i . 48: 426-432. Renkema, J.A. and J . S t e l w a g e n . 1979. E c o n o m i c e v a l u a t i o n of replacement r a t e s i n d a i r y herds. I . Reduction of replacement r a t e s through improved h e a l t h . L i v e s t o c k P r o d u c t i o n S c i e n c e 6: 15-27. R e n n i e , J.C. 1956. Causes of v a r i a t i o n i n c a l v i n g i n t e r v a l o f H o l s t e i n - F r i e s i a n cows. J . Dairy S c i . (Abstr.) 39: 932. Report.  1976. D a i r y s i r e a p p r a i s a l . A g r i c u l t u r e Canada.  Direct sire  comparison.  R o b e r t s o n , A. 1959. Experimental design i n the evaluation of g e n e t i c parameters. B i o m e t r i c s 15: 219-226. R o b e r t s o n , A. a n d J . S . F . B a r k e r . 1966. The c o r r e l a t i o n b e t w e e n f i r s t l a c t a t i o n m i l k p r o d u c t i o n and l o n g e v i t y in dairy cattle. A n i m . P r o d . 8: 2 4 1 - 2 5 1 . S c h a e f f e r , L.R. and C R . H e n d e r s o n . 1972. d r y and d a y s open on H o l s t e i n m i l k J . D a i r y S c i . 55: 107-112.  E f f e c t s o f days production.  S c h a e f f e r , L.R. a n d E.B. B u r n s i d e . 1974. S u r v i v a l rates of tested daughters of s i r e s i n a r t i f i c i a l insemination. J . D a i r y S c i . 57: 1394-1400.  - 130  -  S c h a e f f e r , L.R., M.G. F r e e m a n and E.B. B u r n s i d e . 1975. Evaluation of Ontario H o l s t e i n d a i r y s i r e s f o r milk and f a t p r o d u c t i o n . J . D a i r y S c i . 58: 1 0 9 - 1 1 5 . Seath,  D.M. 1940. The i n t e n s i t y and k i n d o f s e l e c t i o n a c t u a l l y p r a c t i s e d i n d a i r y herds. J. Dairy S c i . 23: 9 3 1 - 9 5 1 .  S m i t h , J.W. and J . E . L e g a t e s . 1962. R e l a t i o n o f days open and d a y s d r y t o l a c t a t i o n m i l k and f a t y i e l d s . J . D a i r y S c i . 45: 1192-1198. S p o o n e r , R.L. 1978. Reasons f o r c u l l i n g i n d a i r y herds. P r o c . of B r i t i s h C a t t l e B r e e d e r ' s c l u b m e e t i n g , C a m b r i d g e , J a n u a r y 197 8; pp. 4 3-4 8. S w i g e r , L.A., W.R. H a r v e y , D.O. E v e r s o n and K.E. G r e g o r y . 1964. The v a r i a n c e o f i n t r a c l a s s c o r r e l a t i o n i n v o l v i n g g r o u p w i t h one o b s e r v a t i o n . Biometrics 20: 818-826. Tallis,  G.M. 1959. Sampling e r r o r s of genetic c o r r e l a t i o n c o e f f i c i e n t s c a l c u l a t e d f r o m a n a l y s i s o f v a r i a n c e and covariance. A u s t . J . S t a t . 1: 35-43.  T r i m b e r g e r , G.W. and M.G. Fincher. 1956. R e g u l a r i t y of e s t r u s , o v a r i a n f u n c t i o n and c o n c e p t i o n r a t e s i n dairy cattle. New Y o r k A g r . E x p t . S t a . , B u l l . 911. TRP.  1977. T r i a n g u l a r Regression Package. Computing U n i v e r s i t y of B r i t i s h Columbia, Vancouver.  Centre,  Van  V l e c k , L.D. 1964. F i r s t l a c t a t i o n performance herdlife. J . D a i r y S c i . 47: 1000-1004.  and  Van  V l e c k , L.D. 1964. Genetic parameters of five-month l a c t a t i o n records. J . D a i r y S c i . 47: 421-425.  Van  V l e c k , L.D. 1966. Change i n v a r i a n c e c o m p o n e n t s a s s o c i a t e d w i t h m i l k r e c o r d s w i t h t i m e and i n c r e a s e i n mean p r o d u c t i o n . J . D a i r y S c i . 49: 36-40.  Van  V l e c k , L.D. , L.H. W a d d e l l and C R . Henderson. 1961. Components o f v a r i a n c e a s s o c i a t e d w i t h m i l k and fat records of a r t i f i c i a l l y s i r e d H o l s t e i n daughters. J . A n i m . S c i . 20: 812-816.  Van  V l e c k , L.D. and G.E. B r a d f o r d . 1965. Comparison of h e r i t a b i l i t y e s t i m a t e s f o r d a u g h t e r dam r e g r e s s i o n and p a t e r n a l h a l f - s i b c o r r e l a t i o n . J . D a i r y S c i . 48: 1372-1375.  - 131 -  V e r d e , O.G., C . J . W i l c o x , F.G. M a r t i n a n d C.W. R e e v e s . 1972. G e n e t i c t r e n d s i n m i l k p r o d u c t i o n i n F l o r i d a D a i r y H e r d Improvement' A s s o c i a t i o n h e r d s . J . Dairy S c i . 55: 1010-1012. W h i t e , J.M. and J.R. N i c h o l s . 1965. R e l a t i o n s h i p s b e t w e e n f i r s t l a c t a t i o n , l a t e r p e r f o r m a n c e , and l e n g t h o f herd l i f e i n H o l s t e i n - F r i e s i a n c a t t l e . J . Dairy S c i . 48: 468-474. Wilcox,  C . J . , S.N. G a u n t a n d B.R. F a r t h i n g . 1971. Genetici n t e r r e l a t i o n s h i p s o f m i l k c o m p o s i t i o n and y i e l d . S o u t h e r n C o o p e r a t i v e S e r i e s B u l l . 515. A g r i c . Exp. S t a t . U n i v e r s i t y o f F l o r i d a , G a i n s v i l l e , F l o r i d a .  Wilcox,  C . J . , K.O. P f a u and J.W. B a r t l e t t . 1957. An i n v e s t i g a t i o n of the i n h e r i t a n c e of female r e p r o d u c t i v e p e r f o r m a n c e a n d l o n g e v i t y , and t h e i r i n t e r r e l a t i o n s h i p s w i t h i n a H o l s t e i n - F r i e s i a n herd. J . D a i r y S c i . 40: 942-947.  W i l t o n , J.W., E.B. B u r n s i d e a n d J . C . R e n n i e . 1967. The e f f e c t s o f d a y s d r y a n d d a y s o p e n o n t h e m i l k and b u t t e r f a t production of H o l s t e i n - F r i e s i a n c a t t l e . Can. J . A n i m . S c i . 47: 85-90. Wunder, W.W. and L.D. M c G i l l i a r d . 1967. Seasons o f c a l v i n g and t h e i r i n t e r a c t i o n s w i t h age f o r l a c t a t i o n a l m i l k yield. J . D a i r y S c i . ( A b s t r . ) 50: 986.  5,  Appendix  1.  Year  least  square means f o r Group 1 cows.  L e a s t Square Means + SE m  „  2  Trait  No.of obs. Milk 1 Fat 1 Milk HYl Fat HYl LLL  1959  1960  1961  2482  2311  2751  2850  4253+22  4372+22  159+.9  158+.8  164+.8  168+.8  Milk/D Cullage  4627+21  4575+21  2625 4728+22  173+.8  176+.8  -1040+15  -1019+17  170+.8  Overall 23018 4456+16 166+.6 -989+8  -954+18  -933+19  -997+17  -992+17  -35+.3  -34+.7  -37+.6  -36+.6  -36+.6  -38+.6  -39+.6  -39+.6  -37+.3  340+1.6  344+1.5  345+1.5  346+1.4  347+1.4  355+1.6  345+.8  1  4921+20  M  341+1.7 4674+34  4659+32  4824+31  174+1.3  175+1.3  175+1.2  182+1.2  13.8+.07  13.7+.07  13.7+.07  14.0+.07  40.9+.05 11.2+.05  .51+.003 40.9+.06 11.2+.06  .51+.003  .53+.003  - 1013+16  1965  -996+16  .51+.003  Fat/D  3617  3307  3075  4272+23  1964  1963  4533+21  158+.9  4691+33  Fat T  1962  4286+23  340+1.6  Milk T  Plife  1958  5010+30  5071+30  5118+29  5318+32  187+1.2  190+1.1  193+1.1  200+1.2  14.5+.06  14.6+.06  14.7+.06  15.0+.07  .54+.003  .55+.003  .55+.003  .56+.003  184+.8 14.3+.05 .53+.002  40.9+.05  41.0+.05  41.0+.05  41.1+.05  41.1+.05  41.3+.05  41.0+.03  11.2+.05  11.3+.05  11.3+.05  11.4+.05  11.4+.05  11.7+.05  11.3+.03  1  Year o f f i r s t  2  U n i t s a r e i n k g , -except C u l l a g e , P l i f e  calving. a r e i n months and L L L i s i n days.  CO NJ  1  Appendix  2.  Year  l e a s t square means f o r Group 2 cows.  L e a s t Square Means +SE Trait  2  No.of o b s . Milk 1 Fat 1  1958  1959  1907  2424  4768+25 176+1.0  Milk HYl Eat HYl Milk L  -485+19  4706+23  1960  1961  3196  3759 4810+22  4707+22  1962  4228 4938+21  1963  4694 5052+20  1964  4678 5123+21  1965  3695 5180+21  175+.9  176+.9  181+.8  184+.8  188+.8  192+.8  194+.8  -515+17  -558+15  -596+14  -588+14  -579+13  -606+13  -605+14  -17+.7  -19+.6  -20+.6  -21+.5  -22+.5  -22+.5  5592+35  5640+32  5687+30  5753+29  5839+28  5923+27 222+1.1  -23+. 5 5953+27  -21+.3 5799+22  211+1.3  213+1.2  216+1.1  219+1.1  LLL  337+2.0  338+1.7  336+1.6  341+1.5  340+1.4  342+1.3  343+1.3  343+1.4  25551+299  26925+282  26129+286  25436+300  Fat T Milk/D Fat/D  25853+420  25563+370  25379+317  24770+337  970+16  961+14  937+13  960+12  14.4+.07  14.6+.07  14.8+.07  15.0+.06  .54+.003  .55+.003  .56+.003  .57+.002  964+11 15. 3+-. 06 .57+.002  1016+11 15.6+.06 .59+.002  226+1.1  992+11  962+11  15.7+.06  15.7+.06  .59+.002  183+.7 -567+8  — 23+.5  209+1.4  Milk T  28581 4911+18  6006+28  Fat L  225+1.1  Overall  .59+.002  217.5+.9 340+.7 25701+174 97 0+7 15.1+,05 .57+.002  Cullage  86.9+.77  85.2+.68  82.9+.62  83.6+.58  83.2+.55  84.9+.51  83.2+.52  81.2+.55  83.9+.31  Plife  57.7+.78  56.0+.68  53.7+.62  54.4+.58  53.9+.55  55.7+.51  54.0+.52  52.0+.55  54 .7+ 31  # Lact  4.4+.055-  4.3+.048  4.1+.044  1  Year o f f i r s t  2  U n i t s a r e i n kg except C u l l a g e , P l i f e  4.1+.042  4.1+.039  4.2+.036  4.1+.037  calving. i n months, L L L i n days and # L a c t i n numbers.  4.0+.039  %  4.2+.022  Appendix 3.  .. Season' ' l e a s t s q u a r e means f o r Group 1 and Group 2 cows. • 1  L e a s t Square Mean + SE GROUP 2  GROUP 1 Trait  8062  No.of o b s . Milk 1  Season 2  Season 1  4354+17  Milk HYl Fat HYl  9165  19416  285B1  4558+16  4456+16  4800+19  5021+18  4911+18  166+.6  179+.7  187+.7  -34+.4  -39+.4  Milk L  NA  NA  Fat L  NA  NA 347+0.9  343+1.0  LLL  -989+8  -18+.3  -21+.3  1 M  5781+24  5817+22  NA  217+.9  218+.9  217.5+.9  345+0.8 4921+20  Fat T  181+.9  184.5+.8  Milk/D  14.0+.05  14.5+.05 .54+.001  -477+9  NA  188+.8  .53+.002  -24+.4  183+.7 -567+8 5799+22  5027+21  Fat/D  • -656+10  -37+.3  4814+23  Milk T  Over.ill  23018  -909+9  -1069+11  Season 2  14956 169+.6  162+.7  Fat 1  Season 1  Overall  14.3+.05  342+1.0  339+0.8  340+0.7  25636+222  25766+185  2570i+174  970+.8  970+.7  970+.7  15.0±-05  15.3+.05  15.1+.05  .56+.002  .53+.002  .57+.002  .57+.002  Cullage  41.0+.03  41.0+.03  41.0+.03  84.1+.40  83.7+.33  83.9+.31  Plife  11.3+.03  11.4+.03  11.3+.03  54.9+.4  54.5+.33  54.7+.31  NA  NA  # Lact 1  Season  2  U n i t s a r e i n kg e x c e p t C u l l a g e ,  1 (March-August)  and s e a s o n 2 (September-February) o f f i r s t Plife  4.2+.029  NA  calving.  i n months, L L L i n days and $ L a c t  i n numbers.  4.2+.023  4.2+.022  LO •» 1  - 135 Appendix 4.  S i r e and e r r o r components o f v a r i a n c e  and c o v a r i a n c e .  Variance or Covariance Groups 1 and 2 Combined Group 2  a  Trait  3  Milk  1  Milk 1  (b)  Fat 1 M i l k HYl F a t HYl  Sire  Error  Sire  Error  27053  471748  21653  410766  534  14796  346  12439  27224  467832  21936  406638  539  14650  355  12282  18384  259502  122  7170  29169  423269  Fat L  540  13357  LLL  795  9705  242642  3733298  144380  2806065  7106  131382  2935  93380  Milk L  Milk T Fat T Milk/D Fat/D Cullage Plife # Lact  70.60  1034.98  1.13  31.42  604.24  55.82 .5739  7120.04  868.05 25.1422  333  5456  115.58  3169.84  338  5508  116.59  3168.26  21.76  369.03  6.10  202.57  661.02  38.57  Fat 1 Fat 1  (b)  43.65  14698  M i l k HYl  536  F a t HYl  43.77  Milk L  667  13309  50  608  Fat L LLL  24.27  Milk T Fat T  7303  37.42  378.57  21.66  242.59  129725  409  5301  290  31.24 1.4855  Cullage  13.77  203.52  Plife  13.92  205.35  # Lact  568.04  280  8289  0.1235  Fat/D  328.16  0.9354  13.8818  572.77 12330  39.12  4397  1.35  Milk/D  656.84  361  92601 3978  .8686  24.9327  .1086  1.2290  5.99. 6.03 .3738  119.25 119.00 7.7292  M i l k HYl M i l k HYl  (b)  27389  481258  22223  418779  541  15180  370  12760  29454  420880  18962  257789  Fat L  545  13312  LLL  787  9728  617  7033  247634  3724256  156387  2808380  7277  131214  3413  93666  Fat.HYl Milk L  Milk T Fat T Milk/D Fat/D Cullage Plife # Lact  71.22 1.14 342 346 22.44  1029.10 31.33  146.15  57.28 .6379  7134.67  864.26 25.0889  5442  133.76  3178.34  5491  135.02  3175.28  7.43  203.60  368.01  Cont'd  - 136 -  Trait  Error  Sire  Error  Sire  43.87  £79.34  39.64  588.48  Fat HYl Fat HYl  (b)  Milk L  678  Fat L  50.26 24.12  LLL  8507  Milk T  416.49  Fat T  1.3765  Milk/D  .1240  Fat/D  300.30  7244.61  606.26  38.30  377.46  329.63  22.09  239.68  13233  129925 5315.39 31.0347 1.4819  Cullage  14.13  203.96  Plife  14.29  205.69  .9633  # Lact  13.9203  4814  93218  306.68  4009.82  .9196  24.8318  .1111  1.2280  6.60 6.64 .4181  120.48 120.18 7.8451  Milk L Milk L  (b)  Fat L LLL Milk T Fat T  31212  1120792  45103  661  38701  27465  1077  32833  46124  1281499  1238 1345 492391  9990406  364642  6989656  16842  367824  11706  251243  Milk/D  92.4 5  Fat/D  2.18  1604 53.19  74.76 1.53  1423.83 46.45 10009 10023  Cullage  771  16779  488  Plife  778  16948  489  # Lact  52.18  1164.66  31.88  648.56  78.94  1928.18  61.17  1717.07  44.07  1003.95  37.61  1222.30  Fat L Fat L  (b)  LLL Milk T Fat T  17566  363312  12246  241882  791  14392  636  9957  1.98  Milk/D  .1695  Fat/D Cullage Plife # Lact  52.15 2.4266  1.29 .1519  44.95 2.1773  30.49  628.72  20. 07  364.58  30.74  635.12  20.11  364.93  2.10  43.64  1.35  23.46  LLL LLL Milk T Fat T Milk/D Fat/D Cullage Plife # Lact  (b)  80.64 16336  4991.48 186725  85.90 16689  605.04  7071.30  640.62  2.52  22.03  2.60  .0822  . 8729  .0992  5138.57 281266 10628.11 30.29 1.1758  313.58  25.81  476.73  27. 44  312.86  25.84  477.47  1.75  9.81  1.60  21.13  27.21  Cont'd  - 137 -  Trait  Sire  Error  Sire  Error  Milk T Milk T  (b)  Fat T Milk/D Fat/D Cullage Plife  6895357  238364462  5976508  .216881820  258369  8946578  223141  8104100  859.53  14148.41  786.68  15066.57  31.03  514.48  27.37  533.74  11857  443989  9574  390128  11931  446865  9554  390507  31936.28  652.87  27579.59  341654  9474  310425  824.25  # Lact Fat T Fat T  (bl  10420 27.09  Milk/D  23.56  505.72  531.33  1.51  20.95  1.49  22.00  Cullage  455.23  16781.99  374.80  14733.07  Plife  457.96  16890.28  373.91  14746.69  31.75  1206.15  25.68  1040.70  Fat/D  # Lact Milk/D Miik/D  (b)  Fat/D  3.9402  .2014  .0040  .1253  . 0037  .1131  19.37  .9262  19.2611  19.44  Cullage  1.22  Plife  1.23  # Lact  3.5783  .2146  .9275  19.2386  .0820  1.3621  .0589  1.3275  .00040567  .00608623  .00041307  .00546823  Fat/D Fat/D  (b)  Cullage  .0524  .7544  . 0421  .7365  Plife  .0529  .7573  .0421  .7353  # Lact  .0036  . 0529  .0028  . 0506  Cullage Cullage  (b)  Plife # Lact  21.13  865.51  16.55  745.74  21.25  871.07  16.50  746.22  1.47  62.25  1.14  52.70  21.38  877.16  16.46  747.26  1.48  62.67  1.14  52.74  Plife Plife  (b)  # Lact # Lact # Lact  (b)  .1035  4.5771  a  U n i t s a r e kg , e x c e p t C u l l a g e , P l i f e  b  V a l u e s a r e components o f v a r i a n c e .  .0794  i n month  3.8460  and L L L i n days .  Appendix  Traits  Milk  1  M i l k HYl Fat  HYl  Milk L  1  Fat  .92  Milk 1 Fat  E n v i r o n m e n t a l c o r r e l a t i o n s f o r Groups Group 2 (below d i a g o n a l ) cows.  5.  M i l k HYl  .98 .90  .91 .98  1  .89  .88  .97  .91  .34  .30  . 33  Fat  HYl  .89  1 and 2 combined  Milk L  Fat L  LLL  . 50  .46  . 17  Milk T  Fat T  .25  .25  .24  .69  .25  .25  .23  .71  .63  .25  .25  .23  .24  .24  .23  .31  .92  .49  .45  .17  .32  .31  .29  .31  .93  LLL  .13  .12  .13  .12  .42  .47  .16  .30  .31  .63  .68  .94  .32  .54  .53  .68  .63  .48  .48  .47  .51  .53  .62  .67  .46  .46  .44  .14  '.14  . 12  . 13  .12  .12  .03  .43  . 41  .98  .98  .97  .42  .42  .98  .98  .97  .89  .31  .30  .30  .30  .29  1.00  .99  .31 .41  Milk T  .29  .26  .28  .26  .41  .37  .24  Fat T  .27  .27  .27  .27  .40  .39  .24  .99  .99 .50  Milk/D  .69  .61  . 68  .59  .69  .61  .19  .52  Fat/D  .61  .65  .60  .64  .64  .68  .19  .49  .51  .91  .97  .97  .36  . 36  .30  Cullage  .18  .18  .18  .18  . 32  .30  .22  Plife  .18  .18  .18  .18  .32  .29  .22  .97  .97  .36  .35  .26  .12  .96  .96  .35  .34  # Lact  .17  .16  .16  .16  .29  « La(  .64  .16  .32  Plife  .65  .48  . 30  Cullage  .73  .46  Fat L  Fat/D  .32  .98  .29  Milk/D  .33  .32  .45  (above d i a g o n a l ) and  .99  1.0 .98  .98  Appendix 6.  Expected breeding values  (EBV)  of s i r e s  f o r p r o d u c t i o n and  longevity  traits.  Traits Sire I.D.  197003 197782 198507 199659 205583 205597 207873 212300 212665 212878 213155 213459 2137*9 214469 214704 215077 217549 218036 218115 219120 220731 221015 227079 228078 229203 229512 230488 231300 2)3108 233528 236866 236937  No. o f Daughters M i l k  135 74 120 87 300 245 150 92 32 51 373 52 786 350 87 120 174 654 106 101 241 173 618 121 397 1017 118 199 49 962 151 166  75.31 -649.20 -72.99 61.21 -424.47 52.22 -268.02 -810.53 -145.84 -529.44 -354.63 128.76 -114.49 351.77 38.47 -645.61 -251.92 180.70 -255.10 520.06 -159.05 -589.15 108.61 57.36 105.09 -68.73 319.2 6 -64.20 -173.28 488.28 184.95 268.94  1  Fat  1  -4.82 -17.78 4.74 -16.94 -3.80 6.53 -11.10 -17.70 -7.04 -24.82 -22.83 -11.97 -14.51 35.62 -8.85 -9.10 -5.4) -2.69 3.80 29.26 6.83 -17.3* 0.46 6.40 2.90 15.81 22.43 2.27 -20.5* 10.00 13.17 -*.49  Milk T  3566.61 -7404.72 945.89 -4366.87 -9916.21 4326.35 212.69 -2568.47 -1582.65 r8748.2 ) -6438.59 3766.48 5880.78 -838. 07 3925.58 -7479.14 1488.74 -61.52 -3098.27 6049.15 4885.82 -7959.94 -4632.40 -179.02 2033.87 7101.90 1967.79 -923.33 -1359.36 -426.83 7066.91 -7059.72  Fat  T  98.99 -257.92 73.26 -236.11 -329.38 172.26 -3.38 -47.18 -44.91 - 3 5 ) . 30 -272.55 108.83 177.86 41.12 126.71 -236.49 68.88 -38.88 -72.14 235.47 261.08 -303.68 -191.77 3.28 75.11 352.21 66.03 -15.6* -99.94 -54.1* 291.4* -30*.5*  Milk/D  0.1253 -1.1125 -0.37*1 0.2037 -1.501* 1.07*9 -0.7*71 -1.8331 -0.**90 -1.2971 -1.395* 0.4913 0.1*52 0.6591 0.2827 -2.3657 -0.8925 0.5751 -0.3899 1.7123 -0.6*63 -2.26*5 0.0562 -0.3915 0.0*19 0.5*61 0.90*4 -0.3901 -0.0995 1.0708 1.0195 -0.1331  Fat/D  Plife  7.8184 -0.0232 -0.0268 -14.6979 3.492fir 0.0088 -8.3686 -0.0505 -0.0254 -17.0079 5.0081 0.0494 I . 2729 -0.0317 -2.5372 -0.0272 -5.3717 -0.0152 -0.0704 -14.5088 -0.0853 -11.7525 6.5489 -0.0266 12.3800 -0.0237 -2.4207 0.0864 7.9115 -0.0102 -0.0436 -11.3617 4.9950 -0.0259 -1.911* -0.0076 -6.0609 0.0256 0.0649 4.7932 0.0205 9.7723 -0.0724 -10.9026 -0.0092 -8.5647 -0.0082 -0.77*1 -0.0017 4.4214 0.0802 11.8512 0.0512 1.4860 0.0009 -2.7704 -0.0533 -0.6894 0.0123 -2.4409 0.0618 I I . 7488 -0.0453 -12.6813  # Lact  0.5160 -1.0042 0.3299 -0.6960 -1.1326 0.2334 0.1562 -0.0821 -0.3864 -1.0550 -0.8399 0.4819 0.8476 -0.1563 0.4577 -0.6640 0.4)57 -0.2544 -0.41)6 0.2498 0.6182 -0.6985 -0.6600 -0.0467 0.3316 0.8768 0.1682 -0.1590 0.0336 -0.2560 0.8299 -1.0011 Cont'd  Traits Sire I.D.  237136 237445 237674 238433 239301 23974* 240227 2*1377 241845 241933 241947 241954 2*203) 242423 2*2 865 243319 243527 244044 244211 2**468 244626 2*519* 245 302 245456 245551 246338 246359 246610 248207 248598 248997 249631 2*9838 250051 250585 250 735  No. o f Daughters M i l k  1053 473 198 116 446 109 101 263 93 380 64 96 53 201 43 201 101 143 39 258 269 1*7 34 11*2 59 499 243 180 65 141 37* 118 167 101 77 562  1  109.92 276.97 -142.45 843.33 453.92 -418.03 -83.79 -454.80 336.41 220.52 •189.80 274.15 22.83 283.41 60.56 72.77 11.38 -139.11 -227.03 -301.52 181.39 -127.9* 350.53 -139.8* -302.20 443.11 353.46 -799.71 153.43 -352.81 -289.38 -8.86 -567.1* - 108.56 -*36.68 -31.02  Fat  1  Milk  T  -6*3.58 16.80 28.22 7748.00 -14.98 3010.01 34.10 -9083.49 0.72 5157.86 -30.46 -8426.75 -7.88 -12607.29 -6.51 -2301.23 8.39 1110.37 7.30 5113.76 -2.15 -3926.59 10.17 2.55 -13.67 -49.43 0. 78 6054.92 2*.)9 -1123.49 7.1* 404.44 -*.*6 818.05 -18.00 -2454.72 -1.46 1069.25 -10.97 -4423.90 -6.48 2456.96 2.83 -3*9.51 -10.26 -3050.56 -3.76 -3085.12 -15.74 -875.46 -0.47 4342.40 5.58 597.53 -28.62 -10894.63 5.67 1373.49 1.23 4016.80 -28.46 -115.88 -0.75 -4260. 76 -6.8* 866.80 8.65 -5907.50 -4.99 -1878.5* 16.51 6936.99  Fat  T  2*. 51 370.41 82.94 -373.09 113.11 -366.13 -497.88 -59.6* 50.38 178.*l -138.60 -7.19 -40.43 176.46 15.70 32.03 0.76 -126.13 80. 84 -164.42 16. 19 23.91 -184.24 -99.29 -47.95 91.75 9.36 -403.56 71.81 210.24 -71.67 -154.04 120.55 -189.01 -56.61 351.38  3  Milk/D  -0.1870 0.8536 -0.6599 1.0926 0.7675 -1.1726 -0.1*72 -1.6692 0.7208 0.538* -0.8552 0.2519 0.2643 1.5009 0.4)88 -0.2821 0.7201 -0.*185 -0.8768 -0.4407 0.7541 -0.3057 0. 5989 -0. 3*01 -0.7*73 1. )78) 0.6769 -1.7570 0.1996 -1.1654 -0.1942 -0.3826 -1.0937 0.2560 -0.07)9 0.6172  Fat/D  0.03)1 0.0889 -0.0*85 0.0326 -0.0238 -0.0960 -0.0262 -0.0352 0.0221 0.0211 -0.0227 0.0103 -0.02*9 0.0213 0.0870 0.0032 0.0093 -0.0488 -0.0087 -0.0150 -0.0219 0.0188 -0.0451 -0.0043 -0.0397 -0.0032 0.0051 -0.0667 0.0203 0.0002 -0.0611 -0.0090 0.0131 0.0406 0.03*) 0.0849  Plife  0.1901 13.5771 8.6150 -17.6157 10.1920 -15.3176 -23.3002 0.1593 0.6096 9.1113 -6.2746 -1.8393 -0.0478 8.4021 -2.0744 0.9598 -1.3202 -3.8227 4.)889 -8.6781 3.0675 0.8667 -8.1075 -4.8)35 0.6465 5.231) -0.8483 -19.7661 3.8876 11.9898 0.8616 -6.8075 3.4592 -13.7175 -).2))6 11.2272  #  Lact  -0.0809 0.9329 0.50*5 -1.3315 0.7479 -1.1076 -1.5912 0.1123 0.1168 0.6119 -0.4401 -0.2181 0.0149 0.6017 -0.1132 0.0827 -0.0881 -0.2217 0.3)07 -0.5623 0.1685 0.1832 -0.6530 -0.)7ll 0.0540 0.33)1 -0.1203 -1.3240 0.1322 0.8682 0.0102 -0.5453 0.2873 -0.8634 -0.163) 0.6524 Cont'd  Traits Sire I.D. 251054 251 647 251671 252189 252334 252697 254196 254293 254339 254 3 55 25444) 254568 255055 259163 255164 255165 255184 255362 255835 255838 255034 256075 256451 256645 256 960 257451 257571 258319 258330 258920 259176 259214 259542 259958 260 0 7 6 260293  No. o f Daughters M i l k 46 154 382 32 116 210 49 456 186 349 494 275 64 252 85 161 245 571 157 109 155 179 205 183 93 62 104 81 85 167 187 93 211 353 83 313  -243.28 141.42 215.53 443.17 -309.76 442.66 -285.99 -23.08 -377.97 -482.15 328.31 123.57 108.88 -299.75 437.10 16.67 122.01 -273.93 192.53 102.82 187.04 333.05 -707.29 -165.62 -107.31 5.32 267.84 -172.31 -509.50 -70.38 41.90 -201.88 -122.88 443.95 -219.85 -289.95  1  Fat 1  Milk T  -5283.66 -5.81 3300.87 1.14 92.60 -8.67 6846.71 13.35 25.92 -9.32 5581.74 10.21 -2555.76 -23.51 -10.34 -1445.86 -1006.59 9.31 -6720.33 11.67 1953.75 23.99 -3359.61 -2.91 -3296.28 3.01 8095.22 13.58 2247.32 9.01 -6441.40 -0.84 1369.25 -0.26 -8231.83 3.14 5164. 14 0.01 -11.22 -1329.61 -1543.24 -5.45 319).18 10.12 -5415.10 -28.12 775.26 -5.60 -9713.21 -9.97 -8607.17 -9.77 -2462.80 5.68 -12.32 -10031.78 956.85 -4.29 1122.58 -9.44 4174.77 -1.44 -17.90 -11136.98 859.74 4.10 12159.46 15.27 2675.52 -16.30 -7940.86 -9.09  3  Fat T  Milk/D  Fat/D  Plife  -164.85 112.31 -67.90 274.95 -1.48 19).87 -151.43 -89.76 31.99 -151.84 113.48 -120.73 -134.06 439.16 47.88 -242.11 32.82 -260.00 177.12 -87.83 -111.74 120.77 -222.93 31.38 -389.57 -390.82 -117.63 -456.86 79.88 23.81 169.12 -460.74 72.54 474.56 88.68 -287.64  -0.711) -0.1230 0.8350 2.0993 -1.1005 1.4858 0.5952 0.2016 -1.0755 -1.8675 0.6128 0.2386 -0.6887 -0.1504 0.5)67 0.2724 0.5417 -0.8708 1.2521 -0.2757 0.1349 1.2919 -1.8034 -0.2727 -0.1250 -0.0886 0.2919 -0.9176 -0.9847 -0.3292 0.7)55 -0.3792 -1.1314 1.5173 -0.6886 -1.4324  -0.0091 -0.0198 -0.0229 0.0825 -0.0311 0.0)85 -0.0104 -0.0220 0.0210 0.0262 0.0611 -0.0064 -0.0333 0.0839 -0.0147 0.0049 0.0014 0.0127 0.0316 -0.0504 -0.0363 0.04)8 -0.0707 -0.0124 -0.0244 -0.0492 -0.0023 -0.0560 0.0063 -0.0282 0.029) -0.0481 -0.0138 0.0577 -0.0307 -0.0376  -9.2757 6.1514 -1.8603 10.1281 2.9714 8.6644 -4.6955 -3.9817 0.4084 -8.0185 3.9296 -6.3766 -5.1216 15.3919 4.9958 -11.2 640 1.7296 -14.2376 6.8050 -0.3570 -2.7294 2.8303 -7.9902 0.7973 -19.7817 -17.3281 -4.9975 -17.2086 3.8119 3.1888 7.3152 -20.6640 3.)622 20.3350 6.7233 -11.4387  t Lact -0.7667 0.3487 -0.1469 0.7182 0.2138 0.6298 -0.2824 - 0 . )16) -0.0545 -0.5909 0.2085 -0.4069 -0.3080 1.0589 0.)7)) -0.8337 0.1)75 -1.0313 0.4939 0.0309 -0.2512 0.1604 -0.5454 0.1385 -1.3554 -1.0932 -0.3740 -1.3076 0.3664 0.0227 0.4202 -1.4071 0.1922 1.2915 0.5022 -0.7836 Cont' d  I  I  Traits Sire I.D. 250315 260599 261345 261442 261481 261594 261992 262153 262208 262241 262612 262688 263002 2630)8 263332 26)475 264804 265)01 266128 266752 267150 267260 267701 268043 2686)0 271386 272170 272270 273372 274043 274514 274558 275932 278746  No. o f Daughters M i l k 1 96 521 148 168 182 70 125 111 265 97 254 210 81 244 267 262 485 311 67 88 844 154 140 335 11) 118 190 67 136 82 80 183 141 246  -145.84 525.43 -296.2 7 723.41 401.89 71.33 171.18 -640.00 69.41 625.27 548.25 -53.98 -559.25 -85.99 211.45 393.52 -769.24 -331.91 177.77 40.90 422.90 281.65 -17.75 -218.02 503.82 55.20 626.64 318.53 -270.10 41.87 23.75 -199.50 746.30 96.64  Fat 1  Milk T  9.77 1.36 -6.93 20.83 17.64 2.75 6.00 -26.01 -7.53 29.15 9.38 -7.82 -17.48 14.15 8.84 2.66 -4.18 11.43 14.80 5.58 9.77 12.98 -2.16 10.44 9.93 -11.27 21.71 9.47 -11.77 -0.71 -11.96 -4.86 31.72 17.24  5891.37 10768.28 2486.55 6627.18 1991.40 753.49 4523.82 -9735.54 -2829.83 3824.69 -7671.55 -3647.38 2687.01 8023.93 9329.89 9568.40 -5981.13 306.53 3829.99 - 3806.08 8595.09 9906.30 2615.95 874.50 4038.60 4293.32 5422.99 -88.20 -384.01 2899.11 -1941.37 -270.18 4320.97 1784.16  U n i t s a r e kg, e x c e p t P l i f e  Fat T 335.99 329.52 118.65 209.65 84.10 36.68 175.68 -372.34 -153.94 157.02 -325.07 -156.95" 118.38 376.54 363.47 301.82 -141.40 98.61 182.20 -127.58 286.74 387. 72 82.54 100.58 134.33 124.45 188.31 -23.87 -22.52 96.47 -106.58 -15.14 189.21 103.84  3  Milk/D -0.10/5 1.6544 -0.4555 2.2201 0.5269 -0.1979 0.5892 -1.7027 0.488) 1.7502 0.8259 -0.6535 -0.6453 -0.4268 -0.0310 0.9554 -2.2472 -0.9433 0.3420 0.5)7) 1.5245 0.901) -0.3928 -0.1967 0.4539 0.3570 1.4783 0.6143 -0. 3248 -0.1139 -0.0775 0.1818 1.6301 -0.1425  Fat/D 0.0458 0.0126 -0.0034 0.0546 0.0227 0.0011 0.0267 -0.0763 -0.0177 0.0930 0.0049 -0.0438 -0.0138 0.0423 0.0021 -0.0050 -0.0095 0.0316 0.0348 0.0299 0.0436 0.0425 -0.0160 0.0502 -0.0014 -0.0237 0.0463 0.0136 -0.0141 -0.0174 -0.0423 0.0156 0.0741 0.0269  i n months and # L a c t i n numbers.  Plife 13.4921 16.4117 4.0853 9.4141 1.5307 1.8736 8.6523 -16.1687 -5.5324 3.5919 -15.5597 -6.3093 6.2376 18.4281 19.8826 17.7008 -6.9092 3.8296 9.4304 -7.1328 12.9490 16.2694 6.8734 2.2274 7.5595 8.9457 8.2085 -0.8970 -0.5158 6.4608 -3.1814 -0.3885 4.9519 3.7632  # Lact 1.0012 1.0866 0.3964 0.6745 0.0507 0.1914 0.5438 -1.0674 -0.4752 0.2093 -1.1606 -0.5500 0.4203 1.2562 1.3212 1.3081 -0.4577 0.1762 0.6937 -0.4525 1.0170 1.3209 0.4224 0.2282 0.5458 0.7140 0.6545 -0.1297 0.0299 0.3776 -0.1725 0.0275 0.2900 0.1956  PUBLICATIONS Hoque, M. 1968. Repeatability of semen characteristics of yearling beef b u l l s . An. S c i . J . of Pakistan 1:34. Hoque, M. and R . J . Cooper. 1968. Relationship between growth rate and semen characteristics in young b u l l s . An. S c i . J . of Pakistan. 1:58. Hoque, M. 1968. Heritability of semen characteristics of yearling beef b u l l s . Presented in 20th All Pakistan Science Conference. Proceedings, Section A, Pg. 132. Hoque, M., M.A. Hashem and Q.M.F. Rahim. 1970. A study on the seasonal variation in semen characteristics of Lohi ram under local environmental conditions of Bangladesh Agricultural University sheep farm. Bangladesh J . of An. S c i . 3:1. Huq, M.A., M. Hoque and Q.M.F. Rahim. 1971. A comparative study of l i v a b i l i t y , growth rate, age and weight at sexual maturity of the 4th generation graded Deshi x White Leghorn, Oeshi x New Hampshire and Deshi x White Cornish. Bangladesh J . of An. S c i . 4:13. Rahman, A.M.M., M. Hoque, W.O. Graves and M.A. L a t i f . 1968. Cost of producing broilers up to 12 weeks of age. An. S c i . J . of Pakistan 1:10?. Rahman, M.M., Q.M.F. Rahim and M. Hoque. 1968. A comparative study of the fleece y i e l d , staple length, percentages of different types of wool fibres and fineness of wool in Local x Lohi grade 1 and East Pakistan Indigenous sheep. An. S c i . J . of Pakistan. 1:52. Rahman, M.M., Q.M.F. Rahim and M. Hoque. 1971. A comparative study of wool quality of Local x Lohi grade 1 and grade 2. Bangladesh J . of An. S c i . 4:9. Huq, M.A., M. Hoque, Q.M.F. Rahim and M.A. L a t i f . 1968. A comparative study of egg production, egg s i z e , f e r t i l i t y and hatchability of the 3rd generation graded Deshi x White Leghorn, Deshi x New Hampshire, and Deshi x White Cornish. An. S c i . J . of Pakistan. 1:105. J a l i l , M.A., Q.M.F. Rahim and M. Hoque. 1971. S t a t i s t i c a l study of some economical t r a i t s of c a t t l e in Bangladesh. Bangladesh J . of An. Sci . 4:52. A l i , S . Z . , M. Hoque and M.A. Hasnath. 1 973. A study of the growth and reproductive performance of Black Bengal goats under farm cond i t i o n s . Indian Vet. J . 50:438. A l i . S.Z. and M. Hoque. 1974. Preservation of bovine semen at room temperature. Bangladesh J . of A g r i . S c i . 1. A l i , M.A. and M. Hoque. 1975. Heritability of body weight and shank length at 8 weeks of age in New Hampshire and R.I.R. chicks. Bangladesh J . of An. S c i . 5:71.. Hoque, M. and John Hodges. 1979. Genetic and phenotypic parameters of lifetime production t r a i t s in Holstein cows. Presented at the 74th Annual Meeting of the American Dairy Science Association, June 24-27, 1979, Utah State University, Logan, Utah. J . Dairy S c i . 62 (Abstract): 108. Hoque, M. and John Hodges. 1980. Genetic and phenotypic parameters of lifetime production t r a i t s in Holstein cows. Submitted for publication in J . Dairy S c i . Nov. 1979. Hoque, M. and John Hodges. 1980. Lifetime production and longevity of cows related to their s i r e ' s breeding values. Submitted for publication In J . Dairy S c i . Nov. 1979.  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0095413/manifest

Comment

Related Items