private study only. The thesis may not be reproduced elsewhere without
the permission of the Author.
THE E STIMATI ON OF GENETIC AND P HENOTYPIC PARAMETERS FOR A S YNTHETI C LEAN MEAT
AND VOO L SHEEP BREED
A thes i s pres e n ted in parti a l fu f i lment of the requi�ements f o r a degree o f
M a s te r o f Agr ic u l tural S c i ence a t Mas sey U n i vers i ty .
BRUCE ROBERT SOUTHEY 1 9 8 9
ABSTRAST
A s tudy o f t h e i n h e r i t an c e and i n t e r r e l at ionsh i ps b e t ween wool , g r o w t h and c ar c as s t ra i t s was c a r ri ed o u t as par t o f t he d e v e l o pmen t o f
a l arge l e an whi t e- faced s i re breed . C r o s s -bred p rogeny , f ro m t h r e e s i re b reeds ( Romney , D o rs e t , and B o r d e r Le i ces t e r ) m at ed t o Romney ewes , prov i d ed i n forma t i on on carcass fa tness and c ompos i t i on , l i v ew e i gh t , u l t ra-s o n i c bac k f a t dep t h , f lee cewe i g h t and obj e c t i v e m e as u res o f f l e e c e charac t e r i s t i cs . An overall t o t a l �e-t a r o f 2 8 s i r e s and 7 6 5 p rogeny were u s ed t o c o l l e c t t h i s i n f o r ma t i o n .
The analys i s o f h al f -s i b reco rds was carr i ed ou t u n d e r an a s s u m p t i on of p o s i t i ve as s o r t ive ma t i ng on u l t ra- s on i c backfa t de p t h . I t w a s cons i d e r ed t h a t any b i as , rela t i ve t o random m a t i ng , was m i n imal d u e to in comp l e t e as s o r t m en t , dom i nance , ep i s t as i s and c r o s s b r ee d i ng i n f lu ences . I t was a s s umed t h a t t he progeny we r e only h a l f - s i b s i n r e la t i on t o breed , and t h u s t he be tween-b reed compon e n t o n ly e s t i ma t ed o n e - q u a r t e r o f t h e b e t we e n - b reed va r i ance . Fur t he r , t he s i re s we r e n e s t ed wi t h i n t he i r respe c t i ve breeds . The d at a c o r r e c t e d f o r t h e s i gn i f i can t non-gene t i c e f f e c t s b e f o r e t he v ar i an c e and cov ari an c e c o m po nen t s were e s t i ma t ed .
I n gener al , t he e s t i m at e s o f t h e Vi t h i n - b reed h e r i t ab i l i ty f o r t he woo l and grow t h t r ai t s r anged f rom 0.1 t o 0.6 and w e r e s i mi l ar t o l i t e r at u r e v alues . The c ar c as s e s t i m ates were h i g h e r t h an l i t er a t u r e v al u e s in mos t c as e s . The i n c o r po r at i on o f t he b e t w e en -b r eed compone n t res u l t ed i n t h e b e tween - b r e e d h e r i t ab i l i t y b e i ng l arger i n m agni t ud e .
i i i
T h i s ¥as may o f been due t o non-add i t i ve gene t i c e f fec t s , such a s
h e t e r o s i s , i n t h e be tween - b reed componen t . The r a t i o o f t h e b e t ween-b reed gene t i c v a r i an c e t o the t o t a l gene t i c v a r i an c e i nd i c a t ed
t ha t t he r e was l a rge be twee n - b reed vari a t i o n i n l i vewe i gh t and w o o l t ra i t s a n d s ma ll var i a t i o n i n t h e c a r c a s s t ra i t s .
T h e t o t a l gene t i c and t o t al pheno t y p i c correla t i on s p r e s en t e d here s ugges t that s e l ec t i on f o r l e a n grow t h and wool p ro d u c t i on can be a c c o m p l i shed by the j o i n t s e l e c t i on of l i vewe ig h t and greasy f l e e c ew e i gh t . Expec t e d c o r re l a t ed responses i n the o t he r t ra i t s w o u l d i n c l u d e: a ) i n c rease l i vewe i gh t a n d f lee cewe i gh t a t a l l ages , i n crease u l t r a - s on i c fa t dep t h , GR measuremen t , lean con t en t , c lean f l eecewe i gh t , s t ap l e leng t h , mean f i bre d i am e t e r , c lean s coured y i e l d , and b ) d e c rease t he carcass C measuremen t , decrease bone and f a t c o n t en t s , and l o o s e woo l bu l k .
S e le c t i on aga i ns t u l t ra- s on i c backf a t dep t h wou l d resu l t i n leaner a n i m a l s at a c o ns t an t we igh t . Bu t t he mod e r a t ely pos i t i ve c o r r e l a t i ons w i t h l i vewe i g h t and f l e e cewe i gh t would appear t o nega t e t h e a s s o c i a t e d a d v an t age o f a reduc t i on i n c a r cass f a t n es s .
ACKNOWLEDGEMENTS
My d e e pe s t g ra t i t u d e i s ex t ended t o my s u p e r v i so r s , D r . H . T . B l a i r a n d P r o f . A . L . Rae , f o r t he i r cons i de r a b l e t i me , e f fo r t and s u p po r t .
I am d ee p ly i n d e b t ed to Ca rol Bu r t f o r her exce l lent h el p . I a m a l s o i nd eb t ed t o Mr . J. Dobb i e . S pec i a l t h anks to Dr . A . C . P a r ra t t , D r C . A . M o r r i s , and t h e o t h e r peo p l e a t Ruakur a who have h e l ped . A l s o t h anks m u s t g o t o t h e f a r m s t a f f o f d a t a c o l l e c t i on a n d t o t h e s t a f f a t t h e w o o l labo ra t o r i e s .
I a l s o ex t end my t hanks t o the s t a f f i n t he Depa r t me n t o f An i ma l S c i en c e , par t i cu l a r ly P r o f . R . D . Anderson f o r the i r t i me , e f fo r t and h e l p i n v a r i ous ma t t er s. And a l so to t he pos tgradua t es i n An i ma l S c i en c e , espec i a l ly Car l o s S o s a , Meng J i ao Sh i and J o hn Rend e l , f o r t he i r f r i en d s h i p , h e lp and o t h e r ma t t ers d u r i ng my s t u d y . A s pe c i a l t hanks g o t o m y f r iend s M u r r ay , Jane , C i ndy and t h e o t h e r s f o r many t h i ngs .
F i na l l y , I ex t end a ext remely s p e c i a l thankyou ( t o say t he l e as t ) t o my p aren t s and f am i ly for t he i r suppo r t , encouragemen t e t c . in my s t u d i e s .
( And t o t h o s e I h ave forgo t t en T A . )
CHAPTER ONE CHAPTER TWO
TABLE O F CONTENTS
AB STRACT
ACKNOWLEDGEMENTS TABLE OF CONTENTS LI ST O F TABLES L I ST OF FIGURES I NTRODUCTION LITERATURE REVIEIJ 2 . 1 IJOOL PRODUCTI ON
2 . 2 G ROUTH AND MEAT PRODUCTION 2 . 2 . 1 Growth and the Ca r c ass
2 . 2 . 2 Se l e c t i on Ind i ces F o r Leanness 2 . 2 . 3 D i r e c t Se l e c t i on f o r l eanness 2 . 3 THE RELATI ONSHI P BETUEEN UOO L ,
M EAT AND GROWTH TRAITS
2 . 3 . 1 The Rela t i onsh i p B e tween Grow t h And Voo l T r a i ts
2 . 3 . 2 The R e la t i onsh i p Be tween Woo l And C a r c ass T r a i ts
2 . 3 . 3 S e l e c t i on For H i gh And Low Wean i ng W e i gh t
2 . 4 POSITIVE AS SORTATIVE MATI NG 2 . 4. 1 Bas i c Theo ry
2 . 4 . 2 Exper i men t a l Resul t s
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v i i i x i 1 3 3
1 2 1 2 2 2 2 4
2 6
2 6
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3 4 3 6 3 6 3 9
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CHAPTER T HR E E MATERIALS AND METHODS 3 . 1 THE DATA
4 2 4 2 4 2 4 3 5 1 5 1 5 1 5 6 5 7 6 1 6 5 7 0 7 0 7 3 7 7 8 4 C HAPTER F O UR
3 . 1 . 1 Background
3 . 1 . 2 The Da t a Used I n Th i s Analys i s 3 . 2 STAT I STICAL PROCEDURE
3 . 2 . 1 Background
3 . 2 . 1 . 1 Asso r t a t i ve M a t i ng
3 . 2 . 1 . 2 B e tween-Breed Parame t e rs 3 . 2 . 2 Analys is P rocedure
3.2 . 3 The Es t i ma t i o n O f H e r i t abi l i ty 3 . 2 . 4 Es t i m a t i o n o f t h e C o r r e la t i ons RE SULT S AND DI SCU S S I ON
4 . 1 Leas t Square Means o f t h e P rogeny
4 . 2 The Es t i ma t es o f t he Non-gene t i c E f fe c ts 4 . 3 The Es t ima t es of H e r i t ab i l i ty
4 . 4 The Gene t i c And Pheno typ i c Co rre l a t i ons
4 . 4 . 1 Be t ween t h e Li vewe i g h t and C a r c ass T r a i ts 8 4 4 . 4 . 2 Between T h e \.Too l T r a i ts 9 1 4 . 4.3 The C o r r e l a t i ons Be t ween L i v ewe i gh t
and F le e cewe i gh t 9 5
4 . 4 . 4 The C o r re l a t i on s B e t ween Fleecewe i g h t
and Carcass Tra i t s 9 9
4 . 4 . 5 The Co r r e l a t i on s B e t ween Ul t ra-son i c
Back f a t De p t h And The O ther Trai t s 1 00 4 . 4 . 5 . 1 Be t ween Ul t ra-so n i c Back f a t Dep t h ,
L i vewe i gh t and Carcass T r a i t s 100 4 . 4 . 5 . 2 Be t ween Ul t ra-sonic Backfa t Dep t h
A n d The Woo l Tra i t s 104
CHAPTER FIVE CONCLU S I ON BIBLIOGRAPHY
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L i s t o f T a b l es
T a b l e T i t l e
2 . 1 Es t i ma t es o f the E f f e c t s o f B i r t h Rank and Regress i on on Age f o r F leecewe i gh t in the New Zealand Romney .
2 . 2 Est i ma t es o f He r i t ab i l i t y o f F lee cewe i gh t and Woo l Qual i ty T ra i t s i n t h e N Z Romney
2 . 3 The G e n e t i c ( g ) and Pheno t yp i c ( p ) C o r r e l a t i ons of F l ee cewe i gh t and Wool Qua l i t y T r a i t s in t he NZ Romney
2 . 4 Her i t a b i l i ty Es t i ma t es o f L i vewe i gh t and U l t ra - s o n i c Backf a t Dep t h at D i f f eren t Ages i n the Romney o r Romney-Der i ved B r eeds
2 . 5 E s t i ma t es o f Gene t i c ( g ) and P h eno t yp i c ( p ) Co r re la t i ons Be t ween L i vewe i gh t Tra i t s i n
the N Z Romney
2 . 6 Some E s t i ma t es o f Nongene t i c E f fe c t s f o r the NZ Romney
2 . 7 Some E s t i ma t es o f H e r i t ab i l i t y o f car cass t ra i t s
5
6
8
1 3
1 5
1 6
17
2 . 8 The Est i ma t es o f Gene t i c and P h en o t y p i c Correla t i ons o f P a r ra t t e t al ( 1 9 8 7 a ) , and , �o l f e t al ( 1 9 8 1 )
2 . 9 Some Es t i ma t es o f t h e Gene t i c ( g ) and Pheno t yp i c ( p ) Cor re la t i ons of L i vewe i g h t and �oo l T r a i ts i n t h e N Z Romney
2 . 10 The Gene t i c Co r re l at i ons Be tween Fleecewe i gh t, L i v ewe i gh t and Carcass T r a i ts F r om
Bo t k i n e t al ( 1 9 7 1 ) .
2 . 1 1 The Gene t i c ( g ) and Ph enoty p i c ( p ) Co rrelati ons of Ultra-so n i c Backfat Depth w i th Li vewe i ght and Fleecewe i ght F r om McEwan et al ( 1 984 )
3.1 Detai ls o f the Numb e r of S i res and To t al P rogeny per S i re B reed and Source of Data
3 . 2 The L i s t o f T r a i ts and The i r Abb reva t i ons
3 . 3 The Coe f f i c i en t o f t h e Expe c t ed Mean Squares For the � o o l T r a i ts
4 . 1 Leas t Square Romney S i re Means and S t andard E r r o rs
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2 8
3 1
3 3
4 4
4 9
58
7 1
4 . 2 Es t i ma t es o f t he Non-Gene t i c E f f e c t s And S t andard E r rors
4 . 3 Var i an c e C omponen t s and the E s t i ma t es o f H e r i t ab i l i t y w i t h S t and ard E r r o r s
4 . 4 T h e Gene t i c and Phen o t y p i c Co rrel a t i ons Be tween the L i vewe i g h t Trai t s .
4 . 5 The Gene t i c and Pheno t y p i c Co rrela t i ons Be tween the Carcass D i mens i on Tra i t s
4 . 6 The Gene t i c and Pheno t y p i c C o r r e l a t i ons Be tween the Carcas s D i men s i on and T i s sue Componen t Tra i t s
4 . 7 The Gene t i c and Phen o t y p i c Co r r el a t i ons Be tween the Car cas s T i s sue Componen t T r a i t s .
4 . 8 The Gene t i c Co rre l a t i on s Be tween the L i vewe i gh t and Carcass T r a i t s .
4 . 9 The Gene t i c and Pheno typ i c Co r r e l a t i ons Be tween t he Wool T r a i t s .
4 . 1 0 The Gene t i c and Phen o t y p i c C o r r e la t i ons Be tween the Woo l a n d Li vewe i g h t Tra i t s .
4 . 1 1 The Gene t i c Correla t i ons Be tween the Wool and Carcass Trai t s .
7 5
7 9
8 5
8 5
8 6
8 7
8 8
9 2
96
97
L i s t o f F i gures
F i gu r e T i t le
3.1 The E f f e c t o f t h e Change i n the M i d - paren t Var i ance ( L ) o n the Her i t ab i l i ty ( h( ) o f an P os i t ively Asso r t a t i ve ly Ma ted T r a i t .
3.2 The P a t h A n alys i s D i ag r am o f the R e l a t i onsh i p Be tween t h e Two Data Se ts
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5 4
6 8
