宁夏地区奶牛体型外貌性状遗传参数估计

Genetic Parameters for Conformation Traits of Dairy Cattle in Ningxia

【目的】体型外貌性状是奶牛育种中较早关注的一类性状,选育体型外貌性状对实现奶牛生产潜力非常关键。试验旨在揭示宁夏地区奶牛体型外貌性状的表型和遗传特征,为宁夏地区开展具有区域特色的奶牛育种提供数据支撑。【方法】本研究收集了宁夏地区32个牧场共32532头荷斯坦牛的体型外貌线性鉴定记录,利用SAS 9.2软件中mixed程序分析了宁夏地区奶牛体型外貌性状的影响因素;使用DMU软件中DMUAI模块估计了20个体型性状、5个部位得分及体型总分的遗传参数,包括性状的遗传力及性状间的遗传相关。【结果】宁夏奶牛各体型外貌性状平均表现与对应性状最优分离差在0.03(乳房深度)~3.73(中央悬韧带)之间,5个部位得分及体型总分平均值介于80.77(尻部)~87.02(体躯容量)之间。头胎产犊月龄、泌乳月份和胎次对宁夏奶牛5个部位得分均有影响。单性状动物模型估计结果显示,宁夏奶牛体型外貌性状具有低至高遗传力,各性状的遗传力估计值介于0.04(胸宽)~0.45(体高)之间;双性状动物模型估计结果显示,体躯容量系统各性状间的遗传相关介于0.04(胸宽和腰强度)~0.72(体高和体躯容量得分)之间,尻部系统各性状间的遗传相关介于0.32(尻宽和腰强度)~0.78(尻角度和尻部得分)之间,肢蹄系统各性状间的遗传相关介于-0.36(蹄踵深度和后肢后视)~0.78(蹄踵深度和肢蹄得分)之间,泌乳系统各性状的遗传相关介于-0.13(中央悬韧带和后乳房附着高度)~0.73(乳房深度和前乳房附着)之间,乳用特征系统各性状间的遗传相关介于0.54(骨质地和棱角性)~0.96(棱角性和乳用特征得分)之间。【结论】宁夏地区奶牛体型性状的表现总体较好,体型外貌性状遗传力介于0.04~0.45之间,遗传相关介于-0.36~0.96之间,相同系统的体型性状间大多存在中高遗传相关。研究结果为宁夏地区奶牛遗传评估提供了可用的遗传参数。

【Objective】Conformation traits have been the focus in dairy cattle breeding,and the selection of conformation traits is crucial for achieving production performance in dairy cattle.This study was conducted to reveal the phenotypic and genetic characteristics of conformation traits,and provide data basis for dairy cattle population in Ningxia.【Method】Conformation linear classification records of 32532 Holstein cows from 32 farms in Ningxia were collected.The mixed procedure of SAS 9.2 software was used to analyze the influencing factors of conformation traits of dairy cattle in Ningxia.The DMUAI module of DMU software was used to estimate the genetic parameters for conformation traits,including the heritability and the genetic correlations among 20 conformation traits,5 composite traits and final score.【Result】The deviations between the average score and optimal score for conformation traits in dairy cattle of Ningxia ranged from 0.03(udder depth)to 3.73(central ligament),and the average score of 5 composite traits and final score ranged from 80.77(rump)to 87.02(body capacity).The age of first calving,lactation month and parity had significant impacts on 5 composite traits of dairy cattle in Ningxia.The results of unisex animal model estimation showed that the conformation traits of dairy cattle of Ningxia had low to high heritabilities,ranging from 0.04(chest width)to 0.45(stature).The results of doublesex animal model estimation showed that the genetic correlations among traits related with body capacity ranged from 0.04(chest width and loin strength)to 0.72(stature and body capacity score).The genetic correlations among traits related with rump ranged from 0.32(rump width and loin strength)to 0.78(rump angle and rump score).The genetic correlations among traits related with feet and leg ranged from-0.36(heel depth and rear legs rear view)to 0.78(heel depth and feet and leg score).The genetic correlations among traits related with lactation system ranged from-0.13(central ligament and rear udder height)to 0.73(udder depth and fore udder attachment),and the genetic correlations among traits related with dairy character ranged from 0.54(bone consistency and angularity)to 0.96(angularity and dairy character score).【Conclusion】The conformation of dairy cattle in Ningxia performed well,with heritabilities ranging from 0.04 to 0.45 and genetic correlations ranging from-0.36 to 0.96.The genetic correlations among traits in a same body system were found to be medium to high.The results could provide genetic parameters for genetic selection of dairy cattle in Ningxia.