中国西门塔尔牛测定日产奶量性状协方差函数估计

Estimation of covariance functions for test day milk yield records of Chinese Simmental cows

利用第一泌乳期 5 70 0个测定日奶量数据 ,使用DFREML( 3 1)估计了测定日产奶量的方差协方差 ,得出方差 -协方差函数矩阵 ,发现勒让德多项式的协方差函数最佳配合阶数是 9,误差方差回归阶数是 5。第一泌乳期加性遗传协方差除泌乳初期约 40～ 60天内测定日产奶量协方差较大外 。

In estimating parameters,9 order of fit for Lengendre polynomial of Day in Milk is better in the model with DxMRR program in software DFREML 3 1 using random regression test day model with data of 5700 in first lactation Results were shown that the additive genetic covariance and permanent environment covariance turned up peaks at the D 40 ～D 60 while other test day covariance curved surface were equal