Genetic Evaluation And Selection Index Construction Of Holstein Cattle In Ningxia Area

The genetic parameters of milk fat percentage,milk protein percentage,somatic cell score,milk yield of 305 days,age at first calving,calving interval and linear classification Scores was estimated by using the DHI data of 2008-2016 in Ningxia area of 29 358 Holstein cows.With the help of DMU V6.0 software,using AI-REML module combined EM algorithm based on multiple traits animal model,influence factors in field,year,season,parity and additive genetic effects for individual animal model,heritability,calculation of target traits genetic correlations and standard deviation.The marginal benefit of each target character was calculated by the difference method,and finally,the selection index model of the dairy cow in Ningxia was constructed.The main results are as follows:1.The heritability of milk fat percentage(FP),milk protein percentage(PP),somatic cell score(SCS),milk yield of 305 days(MYD),age at first calving(AFC),calving interval(CI)and linear classification score(LCS)respectively was 0.14,0.19,0.19,0.31,0.37,0.10 and 0.07,and then the breeding values and genetic correlation of this traits also were calculated2.The weight of MYD,FP,PP,SCS,LCS,AFC and CI respectively was 43,6,11,10,15,12,3.The proportion of production traits,body traits and reproductive traits was 14:3:3.The selected index model is:SINX=20×[43×EBMYD/1132.21+6×EBFP/0.32+11×EBPP/0.17-10×EBSCS/0.84+15×EBLCS/0358-12×EBAFC/56.42-3×EBCI/27.99]+1000...