Department of sheep and goats, Animal Production Research Institute, Agriculture, Research Center, Giza, Egypt.
Department of Animal Breeding and Genetics, Federal University of Agriculture, Abeokuta, Nigeria.
Trop Anim Health Prod. 2021 Apr 24;53(2):286. doi: 10.1007/s11250-021-02721-3.
Data of 475 goats (242 Zaraibi, 84 Baladi, and 149 Damascus) kept at Sakha Farm, belonging to Animal Production Research Institute (APRI), Ministry of Agriculture, Dokki, Cairo, Egypt, from the period of 2011 to 2017 were used to estimate direct (additive) and maternal genetic effects for litter size at birth (LSB). Three animal models were used. Model 1 includes the fixed effects of breed, season, year of kidding, age of doe, and direct genetic effect. Model 2 is similar to model 1 beside the permanent environmental effect. Model 3 is similar to model 2 and includes the maternal genetic, covariance between direct and maternal genetic effects. The effects of breed, season, year of kidding, and age of doe were significant on LSB. Heritability estimates for LSB are 0.19±0.050, 0.19±0.160, and 0.06±0.007, as estimated from models 1, 2, and 3, respectively. Maternal heritability estimate using model 3 was 0.05±0.006. The removal of additive genetic maternal effect and covariance between direct and maternal effects from the model increased heritability of direct genetic effect by 0.13. Annual phenotypic trends for LSB in Zaraibi, Baladi, and Damascus goat breeds are negative. Annual genetic trends for LSB for the three breeds of goats are positive, significant, and being 0.10±0.01, 0.25±0.02, and 0.01±0.001 litter/year for Zaraibi, Baladi, and Damascus, respectively. The present results indicated that selection for LSB will take a long time. The speed and efficiency of selection is expected to increase by use of molecular markers in selection.
利用 2011 年至 2017 年期间在埃及农业部农业生产研究所的 Sakha 农场保存的 475 只山羊（242 只 Zaraibi、84 只 Baladi 和 149 只 Damascus）的数据，估计出生时产仔数（LSB）的直接（加性）和母体遗传效应。使用了三种动物模型。模型 1 包括品种、季节、产仔年份、母羊年龄和直接遗传效应的固定效应。模型 2 与模型 1 相似，除了永久环境效应外。模型 3 与模型 2 相似，并包括母体遗传、直接和母体遗传效应之间的协方差。品种、季节、产仔年份和母羊年龄对 LSB 有显著影响。模型 1、2 和 3 估计的 LSB 遗传力估计值分别为 0.19±0.050、0.19±0.160 和 0.06±0.007。使用模型 3 估计的母体遗传力估计值为 0.05±0.006。从模型中去除加性遗传母体效应和直接和母体效应之间的协方差，使直接遗传效应的遗传力增加了 0.13。Zaraibi、Baladi 和 Damascus 山羊品种的 LSB 年表型趋势为负。这三个山羊品种的 LSB 年遗传趋势为正，显著，分别为 0.10±0.01、0.25±0.02 和 0.01±0.001 只/年。本研究结果表明，对 LSB 的选择需要很长时间。通过在选择中使用分子标记，预计选择的速度和效率将会提高。
