RANKING OF SIRE PROOFS FOR FEMALE FERTILITY OF DAIRY CATTLE, USING DIFFERENT TRAITS, MODELS, AND DATA SETS

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1 SY-6a-36 RANKING OF SIRE PROOFS FOR FEMALE FERTILITY OF DAIRY CATTLE, USING DIFFERENT TRAITS, MODELS, AND DATA SETS J. Claus 1) E. Kalm 1) B. Drees F e d e r a l R ep u b lic o f Germany 1. In tr o d u c tio n S e le c t io n o f s ir e s i s m ainly based on f a t y i e l d in th e FRG. W ith r a is in g p ro d u ctio n l e v e l and h igh usage o f p roved b u lls, r e l i a b l e s i r e p r o o fs f o r so c a lle d secon d ary t r a i t s such as fem ale f e r t i l i t y become n ecessa ry. Female f e r t i l i t y i s a summarising e x p re s s io n f o r a s e r ie s o f d i f f e r e n t t r a i t s, d e s c r ib in g l i f e t i m e p erfo rm a n ce, c a lv in g p erform an ce, o r re p ro d u c tio n. T r a it s d e s c r ib in g re p r o d u c tiv e perform ance o f cows such as NCSN-Return (NR) o r NUMBER o f INSEMINATIONS p er PREGNANCY (N I) a re reco rd ed r o u t in e ly by th e A I in d u s try and by t h i s a v a ila b le w ith o u t e x t r a c o s ts f o r e s tim a tin g b re e d in g v a lu e s. H e r i t a b i l i t y e s tim a te s f o r fem ale f e r t i l i t y t r a i t s u s u a lly are in a range o f hz = o.o1 t o o.1 o. T h is le a d s t o a h igh number o f dau ghters ( app. 2oo ), i f s i r e p r o o fs f o r fem a le f e r t i l i t y should have same r e p e a t a b i l i t y as f o r m ilk t r a i t s. T e s t o f young s ir e s i s based on app. 1oo daughter re c o rd s in th e FRG. T h is s it u a t io n r i s e s the q u e s tio n, w eth er s e le c t i o n o f s i r e s f o r fem ale f e r t i l i t y may be based on p r o o fs w ith r a th e r low r e p e a t a b i l i t y. The paper a n a ly ses ranking o f s i r e p r o o fs betw een d i f f e r e n t t r a i t s, m odels, and d ata s e ts. 1 * I n s t i t u t e o f Animal B reed in g and Anim al Husbandry, C h r is t ia n - A lb r e c h t s - U n iv e r s it S t O ls h a u s e n s tr. 4o - 6 D34oo K ie l 26

2 2. Data and Method 42oo cow re c o r d s have been e x tr a c te d from a t o t a l d a ta s e t o f app. 15o.ooo records". Cows s e le c t e d are d au gh ters from 21 s i r e s, a l l h a vin g p o s i t i v e p r o o fs f o r f a t y i e l d (a v. : 24.3 k g ). Each s i r e was re p r e s e n te d by 2oo d au gh ters, d e v id e d in t o two b a tch es - f i r s t 1oo and f i r s t two hundred d a u gh ters. A I r e c o r d s a f t e r f i r s t c a lv in g w ere used o n ly, because th e s e cows a l l a re mated t o t e s t s i r e s, so t h a t d i r e c t s i r e e f f e c t s a re redu ced t o a minimum. Each r e c o r d had in fo rm a tio n on s i r e i d e n t i f i c a t i o n, d ate o f f i r s t c a lv in g, NON RETURN (checked by g e s t a t io n l e n g t h ), NUM BER o f INSEMINATIONS, m ilk y i e l d d u rin g f i r s t 1oo d a y s, and Non re tu rn o f th e HERD. Non re tu rn o f th e herd was p r e c a lc u la t e d as m oving a v e ra g e o f two y e a r s, u sing t o t a l d a ta s e t. S ir e p r o o fs a re c a lc u la t e d u sing th re e approaches : p (P) Y ±. =/U + s i + e ± j (s ir e s s i f i x ) P ( c > * i j k l = ^ + mi + hj + s i j k + ei j k l m. = m ilk y i e l d c la s s (i= 1 to 3 ) h. = herd non re tu rn c la s s (j= 1 to 3 ) s?..= s ir e s w ith in m, and h. a l l e f f e c t s f i x P(B ) Yi j k l = ^ + (mh)i + kj + s ik + e i j k l (m h ).= m by h - c la s s ( see P (C )) k. 1= month o f c a lv in g = 3 = s i r e w ith in (m h). as random e f f e c t lk 1 2 BLUP s o lu tio n to s.. w ith h = o.o 2 The approaches a re d i f f e r e n t w ith r e s p e c t t o the model and mathem a tic a l s o lu t io n. P (P ) i s the most sim ple p roced u re u sin g n o th in g e l s e but d au gh ter a vera g es ( a i has s c a le e f f e c t o n ly ). P(C ) may be c l a s s i f i e d as a Contemporary Comparison, whereas P(B ) may be re g a rd e d t o be a modern approach f o r s ir e e v a lu a t io n. Comparisons betw een t r a i t s, models (approaches) and d a ta s e ts a re based on PEARSON and SPEARMAN c o r r e la t io n c o e f f i c i e n t s r e s p. T a b le 1 c o n ta in s su b cla ss means m ilk y i e l d by herd non re tu rn f o r both fem a le t r a i t s regard ed - NR and N I. 27

3 TABLE 1 : Female fertility within milk yield and herd fertility classes Limits loo days lactation yield ( kg ) o o 58 2o o Herd class av. >» *» H h 5-63 *> u <U ~ loo 1 X * Oo 1.7o 2) o 5o.2o oo 6 6.ro 1.33 l.iio 1.1* Yield class av lo 52.i*o 1.5o R e s u lts ^NON-RETURN (NR*) 2)NUMBER OP INSEMINATIONS/PHEGN (NI) T a b le 2 shows 21 s i r e p r o o fs f o r two t r a i t s (NR and N I) based on 2oo d au gh ter re c o rd s p er s i r e. Both t r a i t s le a d t o a com parable ra n k in g. U sin g P (C ) p r o o fs, l i n e a r c o r r e l a t i o n comes o u t w ith r = o.9 1, rank c o r r e la t io n i s c lo s e t o th a t w ith r = o.9 o. TABLE 2 : Sire proofs based on 2oo dauhgter records, estimated by different approaches Approach Trait Sire code P(P) NR P(C) NR P(B) P(P) NI P(C) NI P( 3) H o.3o o K o.o9 I ol - o.o5 -.I4 J o.ll B - * o.l2 -.1*4 - o.l*» l.o o3 - o.ol -.*4 A o o.ol *4 P o M l.o o.o2. Q. - 2.* o.o2. N.5 - o.i o.o5 T * o.ol o.o C o.ol o.o9 P *4 o.o2 o.ol U 2.o 2.o o.ll L o.o2.o5 D 5.o * o.o9 a o.o7.3.*4 E *4 S lo.lo o.o7 R Sb.v NI 28 t

4 I r r e s p e c t i v e l y o f th e model used, a l l p r o o fs a re d is t r ib u t e d c lo s e t o n o rm a lity (T a b le 3 ). Ranking o f s i r e p r o o fs w it h in models shows v e r y s im ila r r e s u lt s (T a b le 4 ). Th is i s in p a r t ic u la r tru e f o r th ose b u lls w ith extrem e n e g a tiv e p r o o fs ( ranks 1 t o 4 ). C o r r e la t io n c o e f f i c i e n t s a re in a range from o.8 2 t o o.9 7. I f s e le c t io n o f t e s t s ir e s i s based on app. 1oo d a u g h ters, rank c o r r e la t io n o f p r o o fs f o r fem ale f e r t i l i t y betw een 1oo and 2oo daughters becoms im p o rta n t. T a b le 5 shows th e r e s u lt s f o r NR. In some cases d i f f e r e n t ran kin g o c c u rs, but in g e n e r a l a f a i r l y good agreem ent e x i s t s. T h is a ga in i s e s p e c i a l l y tru e f o r e x tre m e ly n e g a tiv e s i r e s. C o r r e la t io n c o e f f i c i e n t s a re r a th e r low w ith r =.71 t o.82. TABLE 3 : Distribution of sire proofs ( number of sires ) Approach p( p) P(C) P(B> p(p) PU- ) P(B) Trait expected!!r NR NR NI MI MI Range <-»b.v o.51 to - 1.5o o.5o to o.5o lo 9 7 o.51 to 1.5o > 1-51 s,v. 1 o 1 2 o o 1 TABLE 1 : Ranking of sires within different approaches ( 2oo daughters / sire Rank T. 8 ~ :19 2o 21 Approach (Trait) P< P) (NR) H K I J B O A P P U L D G E S R P(C) (HR) H I K B J Q A U L G R T D E S P(B) (NR) H I K B J M A N U T L G R D E S P(P) (NI) H K J B P I A L P G U S E R D P(C) (NI) H K B J P I A C P O T E R U S D P(B) (NI) H B J K C P I A N L P S D U T R Correlation coefficients Combination Trait PEARSON SPEARMAN?(P) - P(C) NR o.95 o.93 P(P) - P(B) NR o.95 o.95 P(C) - P(B) NR.97 o.97 P(P) - P(C> NI o.97 o.q3 P(P) - P(B) NI o p(c) - P(B) NI o.93 o.92 29

5 TABLE 5 : Ranking of Bires within different approaches and data sets (trait : NR) Rank a / H o 21 'Approach (Daughters) P(P) (loo) H K B J M Q P(P> (2oo) H K I J B P(C) (loo) H K Q B J M P(C) (2oo) H I K B J Q P(B) (loo) H K J B M N P(B) (2oo) H I K B J M P T A G U I S D E A F P U L D G E S R N F G C U A S T D E A U L G R T D E S Q F I R U A T S D E A N U T L G R D E S Combination P(P) (I /2 ) P(C) (loo/2oo) P(B) (loo/2oo) Correlation coefficients PEARSON SPEARMAN CO o.7 1 CO.82 o. K 4. D is c u s s io n and C on clu sion Near i d e n t i c a l r e s u lt s ga in ed f o r th e two t r a i t s used a re n ot v e r y much s u r p r is in g, because app. 6 % o f a l l cows need one in s em in a tio n and app. 85 % o f a l l cows need one o r two in s e m in a tio n s. That means both t r a i t s have two c a t e g o r ie s - /1 f o r NR and 1/2 f o r N I. S e le c t io n cou ld t h e r e fo r e be lim it e d t o one t r a i t. Under econom ic c o n s id e r a tio n s e l e c t i o n p o t e n t i a l f o r fem a le f e r t i l i t y i s lim it e d compared to th a t o f f a t y i e l d, g i v in g no room f o r e x p e n s iv e s i r e p r o o fs. The own r e s u lt s have shown t h a t a l l approaches used r e s u lt e d in t o v e r y s im ila r ra n k in g. T h is o b s e r v a t io n may be t y p i c a l f o r c a t e g o r i c a l l y s c o re d t r a i t s. VAN VLECK and KARNER (198o) fo r example a n a lysed s i r e e v a lu a lt io n by BLUP f o r ty p e s c o re t r a i t s. By in s p e c tio n o f th e u n ad ju sted dau ghter fr e q u e n c ie s o n ly s l i g h t d if f e r e n c e s t o BLUP p r o o fs are t o be f in d in t h e i r d a ta s e t. The com parison o f s i r e ra n k in g u sin g s i r e s ' f i r s t hundred and f i r s t two hundred dau ghters came o u t w ith r a t h e r low c o r r e la t io n c o e f f i c i e n t s. C o n s id e rin g a ga in th e lim it e d s e l e c t i o n p o t e n t ia l f o r fem a le f e r t i l i t y, s i r e p r o o f ra n k in g based on lo o dau gh ters may j u s t i f y t o w ithdraw s i r e s w ith e x tr e m e ly n e g a t iv e p r o o fs. 21

6 SUMMARY Due to low h o f fem ale f e r t i l i t y t r a i t s such as NON-RETURN (NR) or NUMBER o f INSEMINATIONS / PREGNANCY ( N i ), s i r e p ro o fs f o r fem ale f e r t i l i t y need app. 2oo daughters to have a r e l i a b i l i t y com parable to p ro o fs f o r m ilk t r a i t s. T e st o f young s i r e s however i s based on 1oo daughter re c o rd a t maximum in the FRG. The p resen t paper a n aly se s ran k in g o f 21 s i r e p ro o fs between two t r a i t s (NR 9o days, N i ), 3 models (d e v ia tio n fro m / ^ o p, CC, B LU P), and 2 data s e ts ( f i r s t hundred and two hundred d a u g h te r s ). Rank c o r r e la t io n between models a re above o.9 o, and between data se ts app. o.8 o. o.9 5, between t r a i t s app. I t i s concluded th a t p ro o fs o f young s i r e s based on 1oo daugh ters may be c a lc u la t e d by a sim ple model. I t is j u s t i f i e d to withdraw young s ir e s w ith extrem ely n e g a tiv e ly p ro o fs f o r fem ale f e r t i l i t y. R E S U M E N Debido a la baja de kxiitxkhlkiaiixfcex los caracteres femeninos de la fertilidad, tales como el'n o-retorn o'(n R ) o el "numero de inseminaciones/gestacion" (N i), se llevaron a efecto pruebas con los sementales en relacion con la fertilidad de las hembras en aproximadamente 2 hijas para poseer unos datos de confianza con destino a lbs controles lecheros. No obstante, la prueba de los novillos se baso sobre 1 hijas como registro maximo en 1 a Republica Federal Alemana. El presente trabajo analiza la oscilacion en 21 pruebas de sementales entre dos caracteres (NR 9 dias, N i), 3 modelos (desviacion de pop CC ^ B L U P ) y 2 lotes (prim er centenar y segundo centenar de hijas). La correlacion entre los modelos fue de mas de,95, entre los c a racteres de aproximadamente,9 y entre los datos aproximadamente,8. Se deduce que las pruebas de los sementales jovenes basadas en 1 hijas pueden calcularse por un modelo sencillo. Esta justificado eliminar todos los jovenes que demuestran caracteres extramadamente negativos para la fertilidad femenina. L it e r a t u r e c it e d : Van V le c k, L.D. and E a rn e r, P.J. 198o s J.D a ir y S ci 63,