Abstract

Data on daily dry matter intake(DMI),daily feed energy intake(DEI),daily feed crude protein intake(CPI),feed total energy efficiency(EFF),feed energy efficiency for milk(EFFM),feed energy for daily gain(EFFD),feed crude protein efficiency(ECP),ECP for milk(ECPM),ECP for body gain(ECPD), milk yield(MY),milk fat yield(FY),milk protein yield(PY),milk fat plus protein plus lactose yield(FPL),daily gain(DG) and mean liveweight(MLW) were obtained. These records, from 151 lactating daughters of 31 bulls,distributed over 5 selecting and breeding farms,which are all operated at principle as open nucleus breeding system(ONBS) by Chinese Simmental Assosiation,were analysed by iteration maximum quadratic variance unbiased estimation(I- MQVUE) fitting a sire model with farm,parity,calving season as fixed effects and sire as random effect.The animals were managed with half confined system in 1st,2nd,3rd and 4th farm while confined system in 5th farm and concentrates were given according to milk yield for all. When cattle in half confined system, DMI was measured with combined inner(ALA of feed and excrement) and outer (Cr203) indicator method. Heritability estimates for EFF, EFFM, EFFD, ECP, ECPM, ECPD, MY, FY, PY, PFL, DG and MLW were 0.56±0.16, 0.46±0.15, 0.12±0.13, 0.05±0.12,0.13±0.13, 0.41±0.15, 0.30±0.14, 0.73±0.17, 0.63±0.16, 0.20±0.14, 0.56±0.16 and 0.03±0.12 respectively. The genetic correlations between efficiency traits and intake traits were negative highly(-0.23~ -0.67) while that between efficiency traits and their respective output traits were high positive(0.10-0.99), and that between DG and milk output traits, MLW and all output traits ranged from -0.59 to -0.92,-0.02 to -0.60 respectively. The results indicate that the correlation response in efficiency may be higher and more suitable for dual purpose breeding objective had layed down when selection on an index including PY,FY and DG than on the index including MY and DG in effect now for Chinese Simmental.

Li JunYa, Chen Dequan, Xu ShangZhong

Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume 25: Lactation; growth and efficiency; meat quality; role of exotic breeds in the tropics; design of village breeding programs; n, , 133-136, 1998
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