期刊
THERIOGENOLOGY
卷 108, 期 -, 页码 81-87出版社
ELSEVIER SCIENCE INC
DOI: 10.1016/j.theriogenology.2017.11.035
关键词
Beef cattle; Cows' productivity; Genetic correlations; Reproductive performance; Zebu
资金
- National Council of Technological and Scientific Development (CNPq) [303259/2016-7]
The female reproductive performance, productivity and size are strongly associated with production efficiency of herds raised in a tropical environment. The age at first calving (AFC), accumulated productivity (AP), stayability (STAY) and mature weight (MW) could be used as indicators of these traits. In this study, the genetic parameters and correlations between AFC, AP, STAY and MW measured in Nellore females were estimated, in order to provide support for the beef cattle evaluation programs. In addition, the genetic changes for these traits were obtained. The (co)variance components were estimated by Gibbs sampling by four-trait multivariate analysis, using a threshold animal model for STAY and linear animal model for the other traits (AFC, AP and MW). Heritability of AFC, AP and STAY showed low values, with posterior means of 0.13 +/- 0.02, 0.14 +/- 0.01 and 0.19 +/- 0.03, respectively. On the other hand, for MW were estimated mean heritability of 0.44 +/- 0.03 and repeatability of 0.77 +/- 0.03, demonstrating the importance of genetic and permanent environmental effects for the expression of beef cows' size. The AFC showed null genetic correlation with AP (-0.06 +/- 0.12) and MW (0.01 +/- 0.09) and low and negative with STAY (-0.15 +/- 0.11). The AP showed high genetic correlation with STAY (0.86 +/- 0.03) and weak with MW (0.23 +/- 0.09). Positive and moderate genetic association was estimated between STAY and MW (0.66 +/- 0.05). Annual direct genetic trends of 0.19 kg, 0.30 units and 0.10 kg were estimated for AP, STAY and MW, respectively, and were significant (P < 0.05) for STAY and MW. For AFC, negative and favorable annual genetic change was estimated (-0.08 months, P < 0.05). In this population, the selection of heifers for an early reproductive age should have little influence, however favorable, in the time that the cows remain in the herd. The use of AP as a selection criterion should result in smaller changes in the females' mature weight when compared to selection based on STAY. (C) 2017 Elsevier Inc. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据