Southern Agricultural Research Institute (SARI), PO Box 05, Hawassa, Ethiopia.
International Center for Agricultural Research in the Dry Areas (ICARDA), PO Box 5689, Addis Ababa, Ethiopia.
Trop Anim Health Prod. 2020 Nov 24;53(1):42. doi: 10.1007/s11250-020-02445-w.
Investigation was carried out to assess the effects of environmental factors and to estimate genetic parameters and trends for reproductive traits in Bonga sheep, Ethiopia. Animals used in this study were managed by two communities involved in a community-based breeding programs (CBBPs) from 2009 to 2018. The database consisted of 15,595 individual phenotypic information from about 1500 ewes with variable number of records for each trait. The traits analyzed were age at first lambing (AFL), lambing interval (LI), and litter size (LS). Fixed effect analysis was done using the general linear model procedures of SAS. The Average Information Restricted Maximum Likelihood method of WOMBAT, fitting univariate animalmodel, was used to estimate heritabilities, repeatabilities and breeding values. Results showed that Bonga sheep had overall mean AFL, LI, and LS of 453 ± 109 days, 254 ± 51 days, and 1.43 ± 0.008, respectively. All traits were influenced (p < 0.01) by lambing year, lambing season, breeder communities, and parity of ewes. Estimates of heritability for AFL, LI, and LS were 0.015 ± 0.143, 0.009 ± 0.070, and 0.085 ± 0.110, respectively. The low heritabilities for the traits are expected and indicate low possibility of achieving rapid genetic progress through phenotypic selection. The repeatability estimates for LI and LS were low (0.109 and 0.196, respectively) indicating that non-genetic factors had significant influence to the variation in these traits among parities; therefore, selection decision on ewes should consider repeated records. The genetic trend for AFL, LI, and LS over the years was significant (p < 0.01). Positive values for LS and negative for AFL and LI were recorded, implying that the well-structured CBBPs have resulted in measurable genetic gains for the reproductive traits.
本研究旨在评估环境因素的影响，并估计博加绵羊的繁殖性状的遗传参数和趋势。这些动物是 2009 年至 2018 年期间，由参与基于社区的繁殖计划（CBBP）的两个社区管理的。该数据库包含了 15595 头个体的表型信息，涉及约 1500 只母羊，每个性状的记录数量不等。分析的性状包括首次产羔年龄（AFL）、产羔间隔（LI）和产羔数（LS）。使用 SAS 的一般线性模型程序进行固定效应分析。使用 WOMBAT 的平均信息限制最大似然方法，拟合单变量动物模型，估计遗传力、重复力和育种值。结果表明，博加绵羊的 AFL、LI 和 LS 的平均值分别为 453±109 天、254±51 天和 1.43±0.008。所有性状均受产羔年份、产羔季节、繁殖者社区和母羊胎次的影响（p<0.01）。AFL、LI 和 LS 的遗传力估计值分别为 0.015±0.143、0.009±0.070 和 0.085±0.110。这些性状的低遗传力预计表明，通过表型选择实现快速遗传进展的可能性较低。LI 和 LS 的重复性估计值较低（分别为 0.109 和 0.196），表明非遗传因素对这些性状在胎次间的变异有显著影响；因此，对母羊的选择决策应考虑重复记录。AFL、LI 和 LS 的遗传趋势多年来一直很显著（p<0.01）。LS 的值为正，AFL 和 LI 的值为负，这表明结构良好的 CBBP 已经为繁殖性状带来了可衡量的遗传增益。
Zotero 插件