Xu Lei, Luo Hanpeng, Zhang Xiaoxue, Lu Haibo, Zhang Menghua, Ge Jianjun, Zhang Tao, Yan Mengjie, Tan Xueting, Huang Xixia, Wang Yachun
College of Animal Science, Xinjiang Agricultural University, Urumqi 830052, China.
College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
Animals (Basel). 2022 Sep 15;12(18):2433. doi: 10.3390/ani12182433.
In this study, we estimated the genetic parameters for 6 composite traits and 27 body conformation traits of 1016 dual-purpose Simmental cattle reared in northwestern China from 2010 to 2019 using a linear animal mixed model. To integrate these traits, a variety of methods were used as follows: (1) genetic parameters estimates for composite and individual body conformation traits based on the pedigree relationship matrix (A) and combined genomic-pedigree relationship matrix (H); (2) factor analysis to explore the relationships among body conformation traits; and (3) genetic parameters of factor scores estimated using A and H, and the correlations of EBVs of the factor scores and EBVs of the composite traits. Heritability estimates of the composite traits using A and H were low to medium (0.07-0.47). The 24 common latent factors explained 96.13% of the total variance. Among factors with eigenvalues ≥ 1, F1 was mainly related to body frame, muscularity, and rump; F2 was related to feet and legs; F3, F4, F5, and F6 were related to teat placement, teat size, udder size, and udder conformation; and F7 was related to body frame. Single-trait analysis of factor scores yielded heritability estimates that were low to moderate (0.008-0.43 based on A and 0.04-0.43 based on H). Spearman and Pearson correlations, derived from the best linear unbiased prediction analysis of composite traits and factor scores, showed a similar pattern. Thus, incorporating factor analysis into the morphological evaluation to simplify the assessment of body conformation traits may improve the genetics of dual-purpose Simmental cattle.
在本研究中，我们使用线性动物混合模型估计了2010年至2019年在中国西北部饲养的1016头兼用型西门塔尔牛的6个复合性状和27个体型性状的遗传参数。为整合这些性状，采用了多种方法如下：(1)基于系谱关系矩阵(A)和基因组-系谱组合关系矩阵(H)估计复合性状和个体体型性状的遗传参数；(2)因子分析以探索体型性状之间的关系；(3)使用A和H估计因子得分的遗传参数，以及因子得分的估计育种值(EBV)与复合性状的EBV之间的相关性。使用A和H对复合性状的遗传力估计为低到中等(0.07 - 0.47)。24个共同潜在因子解释了总方差的96.13%。在特征值≥1的因子中，F1主要与体躯框架、肌肉度和尻部有关；F2与蹄腿有关；F3、F4、F5和F6与乳头位置、乳头大小、乳房大小和乳房形态有关；F7与体躯框架有关。对因子得分进行单性状分析得出的遗传力估计为低到中等(基于A为0.008 - 0.43，基于H为0.04 - 0.43)。从复合性状和因子得分的最佳线性无偏预测分析得出的斯皮尔曼和皮尔逊相关性显示出相似的模式。因此，将因子分析纳入形态学评估以简化体型性状的评估可能会改善兼用型西门塔尔牛的遗传学。
