Institute of Animal Husbandry and Breeding, University of Hohenheim, Stuttgart, Germany.
J Anim Breed Genet. 2012 Oct;129(5):380-9. doi: 10.1111/j.1439-0388.2012.00999.x. Epub 2012 Apr 28.
Reaction norm random regression sire models were used to study genotype-by-environment interactions (G × E) in the German Holstein dairy cattle population. Around 2300 sires with a minimum of 50 daughters per sire and seven first-lactation test day observations per daughter were analysed. Corrected test day records for milk yield, protein yield, fat yield and somatic cell score (SCS) were used. Herd test day solutions for milk traits, milk energy yield or SCS were used as environmental descriptors. Second-order orthogonal polynomial regressions were applied to the sire effects. The results revealed significant slope variances of the reaction norms, which caused a non-constant additive genetic variance across the environmental ranges considered. This pointed to the presence of minor G × E effects. The additive genetic variance increased when the environment improved, that is, higher (lower) herd test day solutions for milk traits (SCS). This was also influenced by pure scaling effects, because the non-genetic variance increased in an improved environment and the heritability was less influenced by the environment. The G × E effects caused very little reranking of the sires for the environmental range considered in this study.
采用反应规范随机回归种公牛模型研究了德国荷斯坦奶牛群体中的基因型-环境互作（G×E）。大约分析了 2300 头至少有 50 头女儿/头且每头女儿有 7 个泌乳期测试日观察值的种公牛。使用了校正后的产奶量、蛋白产量、脂肪产量和体细胞评分（SCS）的测试日记录。使用了乳用性状、乳能产量或 SCS 的群体测试日解决方案作为环境描述符。对种公牛效应应用了二阶正交多项式回归。结果表明，反应规范的斜率方差显著，导致在所考虑的环境范围内加性遗传方差非恒定。这表明存在较小的 G×E 效应。当环境改善时，即乳用性状（SCS）的群体测试日解决方案更高（更低）时，加性遗传方差增加。这也受到纯缩放效应的影响，因为在改善的环境中，非遗传方差增加，而遗传力受环境的影响较小。在本研究考虑的环境范围内，G×E 效应对种公牛的重新排序影响很小。
