宁夏地区荷斯坦牛青年牛繁殖性状遗传参数估计

旨在探究青年牛繁殖性状遗传能力群体遗传参数,评估不同配种季节间青年牛繁殖性状基因型与环境的互作效应(G×E).本研究利用宁夏地区12个牧场2007-2019年荷斯坦牛繁殖事件信息记录,计算青年牛繁殖性状包括:首配日龄(AFS)、初产日龄(AFC)、首次配种后56天不返情率(NRR56)、首末次配种间隔(IFL)、妊娠期...

Estimation of Genetic Parameters of Reproductive Traits of Holstein Heifers in Ningxia

The study aimed to explore the population genetic parameters of reproductive traits of heifers and evaluate the genotype-by-environment interaction(G×E)effect for heifer fertility between different inseminate seasons.The reproductive information of Holstein cows from 12 farms in Ningxia from 2007 to 2019 was used.Totally 30645-44888 heifer reproductive phenotypic records were obtained,including age at first service(AFS),age at first calving(AFC),56-days non-return rate of first insemination(NRR56),interval from first to last inseminations(IFL),gestation length(GL)and conception rate of first insemination(CR).Then,a single-trait animal model was used to obtain heritability of each trait and a bi-variate animal model was also applied to estimate genetic correlations between traits and G×E interaction degree between insemination seasons(genetic correlation of the same trait between different environments,r)with the DMUAI module of DMU.The results showed that the heritabilities and their standard error of heifer reproductive traits were:0.483±0.013,0.231±0.015,0.031±0.007,0.038±0.008,0.216±0.017 and 0.031±0.007 for AFS,AFC,NRR56,IFL,GL and CR,respectively.IFL and GL was significantly and positively correlated with AFC(IFL-AFC:0.812±0.019,P<0.05;GL-AFC:0.119±0.053,P<0.05);NRR56 and CR were significantly and negatively correlated with AFC(NRR56-AFC:-0.274±0.086,P<0.05;CR-AFC:-0.532±0.065,P<0.05).Except for IFL in summer-autumn pair and CR,NRR56,IFL in autumn-winter pair(r>0.8),CR,NRR56,IFL had G×E interaction effects(r<0.8)in other season pairs.For CR,the lowest correlation coefficient was observed for insemination between spring and winter,while the genetic correlation for insemination between spring and autumn was the lowest for NRR56 and IFL.The result indicate that the growth and pregnancy maintenance ability of heifers have preferential genetic selection potential,while the conception ability of heifer is affected largely by environment.It is necessary to take climate condition differences into consideration when heifer fertility traits are genetically evaluated due to the existence of G×E,and use more suitable models to improve the accuracy of genetic selection in breeding practices.