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A S T U D Y O F B I A S E S IN DAJR S I R E E V A L U A T I 0 ::\.
A the s i s pres ented in pa rtial fulfi lrr, ��nt
of the r equi r em ents fo r the degr""E' of M a s te r of Agriculture..!
S ci en c e in Animal S cience at M a s s ey Univ e r s ity
RO BE R T DONA L D A N DE RSO N 1 9 74
A B S T R A C T
A total of 8 , 6 84 fi r s t - lactation r e c o rds produced in thto .'\, ( .. :tr>it
r e gion in the dai rying s ea s on s 1 96 6 - 6 7 to 1 9 72 - 7 3 , inc lusivf- w, :r.c a s s embled. Ba s e d on weighted and unweighted intra - s J:: �
r e g re s s ions of progeny pe rfo rman c e (deviati on from withir- -, and within - y e a r c ontempora ry average) on time , a s e rie s ,-..
e s timates of the g enetic tr end in p roducti on for the periuc '..!J<:: •
obtained. V a riable es timates , allied with large s tanda !'c . , p r e c luded reliable conclus ion s on the nature of the gc�e· ·
By a pplying a mixed m odel s olution method of si::-e-e' :, · but only to a r e s t ricted s ub - s ample of the data ( 2, 155 rec.:·
b r e edin g value s of 47 s i r e s we re e s timated unbia s ed by :"
The numbe r s of r e c o rds involved w e r e too few to allow "
c om pa ri s on of the s e e s timate s with e s timates l)f th' l of the s am e s i res obta ined by the Farm ProC:t,dion D: · N . z. Dai ry Board us ing its m ethod of s i re ev&iuation
Ba s ed on variance com pon ent e s timates obtaint�d . of Hende r s on ' s M ethod I, he ritability of milk yield an:1 .1 wa s e s timated to be 0. 43 and 0. 36 r e s pe ctively. Th·. · · a g r e e well with e s timates repo rted els ewhe re .
A dditiona l estimates of the geneti c tr end w'�re ob· "-l r e gre s s ing the s oluti ons for the fixed effe ct� (s.:.re-gr,H . .::··
of the s i r e evaluation model on tim e .
A C K N O W L E D G E M E N T S
The autho r i s speci ally indebted to hi s s upe rvi s o r , Professor A. L . Ra e , fo r wi s e and invaluable gui dance and a s s 1 s tance in alJ a s pects of the s tudy.
S inc e r e thanks a re due to his c olleague , M r R . A . Ba rton for helpful c riti c i sm of the manus c ript and for a dvic e on many oc c a s i ons .
G rateful ac knowl edgem ent i s made to Dr C . R . Bos weli.
Dr G . A . Wi ckham and M e s s r s C . L . Read and D. J. W il s on fo:·
the i r a s s i s tanc e and guidance in c omputing matte rs .
G ratitude i s extended to M r J. W. Stichbury (N. Z. D;;
for hi s m a king available the data us e d in thi s s tudy and to Mis s V. Bri c kwedde for help in a s s embling the da L:.
It i s a pl ea s ure to a c knowledge M r s E. Ho r s fall io;·
s killed typing of the manus c ri pt .
F inally , v e ry s pecial thanks a r e due t o his wife, R : ':
he r unde r s tanding , s uppo rt and encouragement through(
C hapter
T A B L E O F C O N T E N T S
A B S T R A C T
A C K N O W L E D G E M E N T S L I S T O F T A B L E S
1 I N T R O D U C T I O N
2 R E V I E W O F L I T E R A T U R E
I . T HE IM PO R TANCE O F A C CURA TE SIRE E VA LUA TIO N
II. SIRE E VALUA TION IN NEW ZEALAN D UP TO 1 96 9
A . A g e - C o r r ection Fa cto r s
B . Intra - Si r e R e gres s i on o f Daughter P e rformanc e on Herdmate
P e rforman c e
C . Intra -Sire R e g re s s i on of Future Daught e r Producti on on E stimated T rue Daughter Level
D. New Z ea land Dai ry Board's S i r e Proving S c heme
Ill . SI RE E VA LUATIO N IN NEW ZEA LA N \
SINCE 1 96 9
IV . GENE TIC T RE N D
A . G eneti c T r en d a s a Bias in S i r e E valuation
B . M ethods for E s tim ating Genetic 1.-�.
( 1) Predi ction from the ory . ( 2 ) Es timati on us ix-.5 a control
popul ation .
( 3 ) Es timation in non - expe rimer.::-1-i data .
lL
7
C hapt e r
3 M E T H O D S 43
I .
II .
ES TIMA TIO N O F GENE TIC T RE N D A . Metho d One
B. Method Two
SI RE E VALUATION BASE D ON A MI XE D MO DE L
43 44 46
4 8
A . The Method o f Mixe d Model S oluti on 52 B . A da ptati on o f the Mixed Model Solution
E quations to the Sire Evaluation M odel 5o
C . Va riance C omponent E stimation :)8 ( l ) A pplicati on of Henders on ' s
Method I .
D. C omputation of the S olution to the
60
Mixed Model Equation s .:-.4
E . R e - definition o f the S i r e Evaluati on
Model 6 7
F . G enetic T r end E stimation Bas e d o n th
Mixed Model S olution , 7
4 D A T A
I . SOUR CE O F DA TA
II . DES C RI PTIO N O F DA TA
5 R E S U L T S
I . ES TIMA TES O F GENE TIC T REND A . E s timates Ba s ed on I ntra -Si re
Regr e s s ion
B. E s timates Ba s ed on Mixed Mode]
S olution
II. VA RIA NCE COMPONE N TS
I ll. ES TIMA TES O F SIRE BREE DING VALUE::. '1
C hapt e r Pag
6 D I S C U S S I O N 99
B I B L I O G R A P H Y 1 1 2
A P P E N D I X 1 24
Table 2. 1 2 . 2
4. 1
4. 2 4. 3 4. 4 5 . 1
5 . 2
L I S T 0 F T A B L E S
Relative c ontribution of the four geneti c pathway s to geneti c gain .
N ew Z ealand Da iry Boa r d ' s within - he r d p roduction compa ris on o f i dentified A . I . s i r e d c ows with othe r (non - A . I . ) cows in the 1 9 72 - 7 3 dai rying s ea s on .
C rite ria dete rmining the s uitability o f the lactation r e c o rds .
Statistical de s c ription of the c omplete data . Des c ription of the data when c la s s ifie d a c c o r ding to s i r e c ode .
Des c ription of the edited-A. ! . data m eans a nd standa r d e r ro r s .
E s timate s of gen eti c trend de rived fr om the application of the intra - s i r e r e g r e s sion m ethods of e s timati on .
E stimates of geneti c trend produc ed froP1 the a ppli cation of the mixed m odel s olution net hoc of estimation to the edited- A . ! . data .
5 . 3 Va riance component e s timate s obtaine d from the edite d-A.!. data .
5 . 4 V a rian c e c omponent e s timates r eported by t he N . Z . Dai ry Board.
5 . 5 5 . 6
V a rian c e c ompon ent e s timates (milkfat only) r eporte d by S ea rle ( 1 96 l b) .
E s timate s of va riance c omponent ratios and he ritabilities .
5 . 7 E s timate s of sire b r e eding value s .
5 . 8 Spea rman rank c o r r elation s amongst the b r e e d}I value e s timates given in Table 5 . 7.
Page
6
2 2
7 1 7 3 7 4 75
(' I
T a bl e 5 . 9
5 . 1 0
/ /
E s timated breeding value s of the s i r e s belon ging t o the N . Z . Dai ry Boa r d 1 s prov en bull team in the 1 97 3 mating s ea s on .
S pea rman rank c o r r elation c oefficients ba s ed on the e s timate s of b r e eding value for the s i re s of the N. Z . Dai ry Boa r d1s proven bull team in the 1 9 7 3 mating s ea s on .
Page
96
9 8
