北京市荷斯坦牛头胎产奶量的遗传统计分析  

Genetic Statistical Analysis of First Lactation Milk Yield of Beijing Holstein Cattle

作　　者：张勤[1] 张沅[1] H.Haussmann 刘增廷 

机构地区：[1]北京农业大学动物科学技术学院,北京100094 [2]德国

出　　处：《北京农业大学学报》1995年第4期435-440,共6页

摘　　要：本研究对北京市47头公牛的约13000个女儿的头胎产奶量记录进行了系统的遗传统计分析。首先进行了305 d 奶量校正方法的研究。提出了用于从306～420 d 不同阶段的305 d 奶量校正的线性回归方程。同时分析了影响305 d 奶量的季节效应,根据305 d 奶量在各产犊月份的最小二乘均数和育种值估计及遗传参数估计的特点,建议将12个产犊月份划分为3个产犊季节。利用一公畜模型(考虑公畜间的血缘关系)和 REML 估计法的 EM 算法对遗传力进行了估计,估计值为0.11,低于文献中常见的报道。在取遗传力真值为0.10～0.35时,这个估计值的大样本标准误为0.03～0.08,说明估计值的精确性较低,亦即本资料样本对遗传力估计来说仍然偏小。Using about 13000 first lactation milk yield records of daughters of 47 AI bulls in Beijing, the method for estimation of 305-day milk yield from total milk yield,the effect of calving seasons on milk yield,and the heritability of 305-day milk yield were investigated.For method of estimating 305-day milk yield,the milking days from 306 to 420 were divided into three intervals and for each interval a linear re- gression equation was proposed.Based on the least squared means of the calving months a divison of a year into three seasons was suggested.Using a sire model(with herd-year-season effect and sire effect)the her- itability of 305-day milk yield was estimated with EM algorithm of REML method.The estimate turned out to be 0.11,which is lower than the estimates reported in most literatures.The large sample standard error of the estimate lies between 0.03～0.08,corresponding the true value of h^2 between 0.10～0.35, which indicates that the data set we used is still somewhat too small for estimation of heritability.

关 键 词：荷斯坦牛 产乳量 产犊季节 遗传力 牛 

分 类 号：S823.2[农业科学—畜牧学]