文献类型： 外文期刊

第一作者： Yang, RQ

作者： Yang, RQ;Ren, HY;Schaeffer, LR;Xu, SZ

作者机构：

期刊名称：JOURNAL OF ANIMAL BREEDING AND GENETICS （ 影响因子：2.38； 五年影响因子：2.54 ）

ISSN： 0931-2668

年卷期： 2005 年 122 卷 1 期

页码：

收录情况： SCI

摘要： A two-dimensional random regression model with regressions on days in milk (DIM) and parity number was applied to lactational milk yields in Chinese Simmental cattle. Random regressions were fitted for additive genetic and permanent environmental effects using a two-dimensional polynomial on DIM and parity number. A total of 4340 lactational milk yields from Chinese Simmental cattle which calved between 1980 and early 2000 were used in this study. Variance components were estimated using Bayesian methodology via Gibbs sampling. Variances of random regression coefficients associated with all terms of the polynomials were significant. A covariance function showed that heritabilities of lactational milk yields between 200 and 400 DIM over parities varied between 0.25 and 0.45. Heritabilities of 305-day milk yields from 1st to 6-8th parities were 0.28, 0.30, 0.32 0.32, 0.32, and 0.31, respectively. Ratios of permanent environment variances to total variances at each DIM were greater than corresponding heritabilities. Generally, genetic correlations were higher between lactational milk yields with similar DIM and parity number.

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