Department of Animal and Dairy Science, University of Georgia, Athens, GA, USA.
Poult Sci. 2013 Apr;92(4):923-9. doi: 10.3382/ps.2012-02649.
A multiple trait linear-threshold model was used to analyze data for BW, residual feed intake, breast meat yield (BMY), conformation score (CS), area (AR), tibial dyschondroplasia, valgus, varus, and rotated tibia. Leg soundness traits were considered as binary responses. At the liability scale, the model included the fixed effects of flock-week of hatch, and sex of the bird and the genetic additive effect, and the error terms as random. The random maternal effect was included in the model only for BW. A full Bayesian implementation of the model was straightforward even though large number of traits and missing records were present. As expected, binary traits have the lowest heritability. Heritability ranged from 0.12 for tibial dyschondroplasia to 0.44 for BMY. Genetic correlations between BW and conformation traits were moderate to high. Residual feed intake was negatively correlated with BW (-0.15), AR (-0.13), BMY (-0.04), and CS (-0.12). Genetic correlation between leg soundness traits were generally low and negative with the exception of the correlation between valgus and varus (-0.70) and between varus and rotated tibia (-0.39). Genetic correlations between BW, BMY, CS, and AR with leg soundness traits were in general negative and low in magnitude. Thus, selecting for improved leg soundness will have minimal effect on BW and carcass traits. Furthermore, genetic improvement in residual feed intake will result in improvements in carcass traits. Simultaneous genetic improvement in leg soundness and innovative husbandry practices should improve broiler welfare without significant adverse effects on production efficiency.
采用多性状线性阈值模型分析 BW、残饲采食量、胸肉产量（BMY）、体型评分（CS）、面积（AR）、胫骨软骨发育不良、内翻、外翻和胫骨扭转等性状的数据。腿部健全性状被视为二分类响应。在隶属度尺度上，模型包括孵化周群、鸡的性别固定效应和遗传加性效应，以及随机误差项。随机母体效应仅包含在 BW 模型中。尽管存在大量性状和缺失记录，但该模型的全贝叶斯实现非常简单。正如预期的那样，二分类性状的遗传力最低。遗传力范围从胫骨软骨发育不良的 0.12 到 BMY 的 0.44。BW 和体型性状之间的遗传相关性为中等到高度。残饲采食量与 BW（-0.15）、AR（-0.13）、BMY（-0.04）和 CS（-0.12）呈负相关。腿部健全性状之间的遗传相关性通常较低且为负，除了内翻和外翻（-0.70）以及外翻和胫骨扭转（-0.39）之间的相关性为正。BW、BMY、CS 和 AR 与腿部健全性状之间的遗传相关性通常为负且程度较低。因此，选择改善腿部健全状况对 BW 和胴体性状的影响很小。此外，残饲采食量的遗传改良将导致胴体性状的改善。同时进行腿部健全状况和创新饲养实践的遗传改良，应该可以改善肉鸡福利，而不会对生产效率产生显著的不利影响。
