Institute of Animal Science, PO Box 1, CZ 10401 Prague Uhříněves, Czech Republic.
Animal. 2013 Sep;7(9):1401-13. doi: 10.1017/S1751731113001018. Epub 2013 Jun 18.
The objective of the present review was (i) to survey different approaches for choosing the complex of traits for which economic values (EVs) are calculated, (ii) to call attention to the proper definition of traits and (iii) to discuss the manner and extent to which relationships among traits have been considered in the calculation of EVs. For this purpose, papers dealing with the estimation of EVs of traits in livestock were reviewed. The most important reasons for incompatibility of EVs for similar traits estimated in different countries and by different authors were found to be inconsistencies in trait definitions and in assumptions being made about relationships among traits. An important problem identified was how to choose the most appropriate criterion to characterise production or functional ability for a particular class of animals. Accordingly, the review covered the following three topics: (i) which trait(s) would best characterise the growth ability of an animal; (ii) how to define traits expressed repeatedly in subsequent reproductive cycles of breeding females and (iii) how to deal with traits that differ in average value between sexes or among animal groups. Various approaches that have been used to solve these problems were discussed. Furthermore, the manner in which diverse authors chose one or more traits from a group of alternatives for describing a specific biological potential were reviewed and commented on. The consequences of including or excluding relationships among economically important traits when estimating the EV for a specific trait were also examined. An important conclusion of the review is that, for a better comparability and interpretability of estimated EVs in the literature, it is desirable that clear and unique definitions of the traits, complete information on assumptions used in analytical models and details on inter-relationships between traits are documented. Furthermore, the method and the model used for the genetic evaluation of specific traits in a certain breeding organisation are important for the exact definition of traits, for which the economic values will be calculated, and for the inclusion or exclusion of relationships among traits in the calculation of the EVs in livestock breeding.
(i) 调查用于计算经济价值 (EVs) 的性状复合体选择的不同方法；(ii) 提请注意性状的正确定义；(iii) 讨论在计算 EVs 时，性状之间关系的方式和程度。为此，对涉及家畜性状 EVs 估计的论文进行了回顾。发现不同国家和作者估计的相似性状的 EVs 不兼容的最重要原因是性状定义不一致，以及对性状之间关系的假设不一致。确定的一个重要问题是如何选择最合适的标准来描述特定动物类别的生产或功能能力。因此，本综述涵盖了以下三个主题：(i) 哪些性状最能代表动物的生长能力；(ii) 如何定义在繁殖雌性后续生殖周期中多次表达的性状；(iii) 如何处理在平均值上存在性别差异或动物群体差异的性状。讨论了用于解决这些问题的各种方法。此外，还回顾和评论了不同作者从一组替代性状中选择一个或多个性状来描述特定生物学潜力的方式。还检查了在估计特定性状的 EV 时包括或排除经济上重要性状之间关系的后果。综述的一个重要结论是，为了提高文献中估计的 EV 的可比性和可解释性，最好清楚而独特地定义性状，完整地记录分析模型中使用的假设信息，并详细说明性状之间的相互关系。此外，在特定育种组织中特定性状的遗传评估中使用的方法和模型对于准确定义将计算经济价值的性状以及在计算家畜育种中的 EV 时包括或排除性状之间的关系非常重要。
