Department of Animal and Dairy Sciences, University of Georgia, Athens, GA 30602.
Faculty of Agricultural Sciences and Food, University Ss Cyril and Methodius, 1000 Skopje, Macedonia; and.
Poult Sci. 2018 May 1;97(5):1511-1518. doi: 10.3382/ps/pex431.
Four performance-related traits [growth trait (GROW), feed efficiency trait 1 (FE1) and trait 2 (FE2), and dissection trait (DT)] and 4 categorical traits [mortality (MORT) and 3 disorder traits (DIS1, DIS2, and DIS3)] were analyzed using linear and threshold single- and multi-trait models. Field data included 186,596 records of commercial broilers from Cobb-Vantress, Inc. Average-information restricted maximum likelihood and Gibbs sampling-based methods were used to obtain estimates of the (co)variance components, heritabilities, and genetic correlations in a traditional approach using best linear unbiased prediction (BLUP). The ability to predict future breeding values (measured as realized accuracy) was checked in the last generation when traditional BLUP and single-step genomic BLUP were used. Heritability estimates for GROW, FE1, and FE2 in single- and multi-trait models were similar and moderate (0.22 to 0.26) but high for DT (0.48 to 0.50). For MORT, DIS1, and DIS2, heritabilities were 0.13, 0.24, and 0.34, respectively. Estimates from single- and multi-trait models were also very similar. However, heritability for DIS3 was higher from the single-trait threshold model than for the multi-trait linear-threshold model (0.29 vs. 0.19). Genetic correlations between growth traits and MORT were weak, except for maternal GROW, which had a moderate negative correlation (-0.50) with MORT. The genetic correlation between MORT and DIS1 was strong and positive (0.77). Feed efficiency 1, which was moderately heritable (0.25) and is highly selected for, was not genetically related to MORT of broilers and other disorders. Broiler MORT also had moderate heritability (0.13), which suggests that MORT and FE1 can be improved through selection without negatively impacting other important traits. Selection of heavier maternal GROW also may decrease offspring MORT.
四种与性能相关的特征[生长特征（GROW）、饲料效率特征 1（FE1）和特征 2（FE2）以及解剖特征（DT）]和四种分类特征[死亡率（MORT）和三种障碍特征（DIS1、DIS2 和 DIS3）]使用线性和阈值单因素和多因素模型进行了分析。现场数据包括来自科宝-凡特瑞斯公司（Cobb-Vantress, Inc.）的 186596 只商品肉鸡记录。平均信息限制最大似然和基于 Gibbs 抽样的方法用于在传统的最佳线性无偏预测（BLUP）方法中获得方差分量、遗传力和遗传相关的估计值。在最后一代检查了使用传统 BLUP 和单步基因组 BLUP 时对未来育种值的预测能力（以实现的准确性来衡量）。在单因素和多因素模型中，GROW、FE1 和 FE2 的遗传力估计值相似且适中（0.22 至 0.26），但 DT 的遗传力较高（0.48 至 0.50）。对于 MORT、DIS1 和 DIS2，遗传力分别为 0.13、0.24 和 0.34。单因素和多因素模型的估计值也非常相似。然而，来自单因素阈值模型的 DIS3 的遗传力高于来自多因素线性阈值模型的遗传力（0.29 比 0.19）。生长特征与 MORT 之间的遗传相关性较弱，除了母本 GROW 与 MORT 呈中度负相关（-0.50）外。MORT 与 DIS1 之间的遗传相关性较强且为正（0.77）。饲料效率 1 具有中度遗传力（0.25），且高度选择，与肉鸡和其他障碍的 MORT 没有遗传关系。肉鸡 MORT 也具有中度遗传力（0.13），这表明 MORT 和 FE1 可以通过选择得到改善，而不会对其他重要特征产生负面影响。选择较重的母本 GROW 也可能降低后代的 MORT。
