VARIANCE-COMPONENTS DUE TO DIRECT AND MATERNAL EFFECTS FOR GROWTH TRAITS OF AUSTRALIAN BEEF-CATTLE
VARIANCE-COMPONENTS DUE TO DIRECT AND MATERNAL EFFECTS FOR GROWTH TRAITS OF AUSTRALIAN BEEF-CATTLE
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DOI：
10.1016/0301-6226(92)90017-x
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发表时间：
1992-06-01
期刊：
影响因子：
--
通讯作者：
MEYER, K
中科院分区：
文献类型：
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作者：
MEYER, K
采用限制性最大似然法估计了澳大利亚赫里福德、安格斯和瘤牛的初生重、断奶重、一岁重和终重的方差分量。六种不同的动物模型适合每个性状和品种，从一个简单的模型，动物作为唯一的随机效应，最全面的模型，允许遗传和环境的母体效应和遗传之间的协方差直接和母体效应。最详细的模型通常提供最佳拟合的数据，虽然模型之间的差异至少有一个母体效应（遗传或环境）往往不显着。忽略母体效应，直接遗传力（h2）估计值被大幅夸大，特别是在断奶前的生长。除了安格斯的最终体重外，在所有分析中均发现了显著的母体效应。h2的相对大小、母体遗传力和直接-母体遗传相关（r（AM））在品种间存在显著差异。对于安格斯，r（AM）是低的，积极的，没有显着差异为零的所有性状。对于赫里福德和Zebu Cross牛，r（AM）为负值，对于断奶重为中等偏大（-0.59和-0.78），对于一岁重稍小（-0.48和-0.39）。对于赫里福德，母亲的环境影响始终比母亲的遗传效应更重要。
Variance components for birth, weaning, yearling and final weight in Australian Hereford, Angus and Zebu Cross cattle were estimated by Restricted Maximum Likelihood. Six different animal models were fitted for each trait and breed, ranging from a simple model with animals as the only random effect to the most comprehensive model allowing for both genetic and environmental maternal effects and a genetic covariance between direct and maternal effects. The most detailed model generally provided the best fit to the data, though differences between models with at least one maternal effect (genetic or environmental) were often not significant. Ignoring maternal effects, direct heritability (h2) estimates were inflated substantially, in particular for growth till weaning. Significant maternal effects were found in all analyses except for final weight in Angus. There were marked differences between breeds in the relative magnitude of h2 and the maternal heritability, and the direct-maternal genetic correlation (r(AM)). For Angus, r(AM) was low, positive and not significantly different from zero for all traits. For Hereford and Zebu Cross cattle, r(AM) was negative, moderate to large for weaning weight (-0.59 and -0.78) and somewhat smaller for yearling weight (-0.48 and -0.39). For Herefords, maternal environmental effects were consistently more important than maternal genetic effects.