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Abstract：
The aim of this study was to analyze suitable genetic models and selection indices to estimate the genetic parameters and breeding values of native Thai roosters. A total of 3475 records of seven semen traits (mass movement, semen pH, semen color, volume, sperm viability, sperm abnormalities, and sperm concentration) from 242 Thai native grandparent roosters were analyzed. Multiple-trait random regression test-day models with five covariance functions were used to analyze the variance components, genetic parameters, and breeding values. The selection index (SI) was calculated to determine the optimal genetic value for different selection percentages. The results showed that a multiple-trait random regression test-day model with a second-order Legendre polynomial function was the most appropriate genetic model for this population. The estimated heritability values were low to moderate, ranging from 0.110 to 0.112 (mass movement), 0.040 to 0.051 (semen pH), 0.092 to 0.097 (semen color), 0.220 to 0.225 (semen volume), 0.067 to 0.083 (sperm viability), 0.086 to 0.099 (sperm abnormalities), and 0.134 to 0.138 (sperm concentration). The repeatability values exceeded the heritability values and were within the range of 0.133 to 0.688. The genetic correlations among semen traits ranged from -0.332 to 0.677, and phenotypic correlations ranged from -0.260 to 0.460. When considering heritability and genetic correlation values, semen volume, sperm concentration, and mass movement were the top three priority semen traits calculated as selection indices. Finally, the top 10% of the selection index was recommended for creating the next generation. Our findings provide useful information on genetic parameters and an appropriate selection index of semen traits for selecting the genetics of individual Thai native grandparent roosters. The heritability estimates for semen traits reported here suggest an adequate response to selection through a genetic evaluation approach. Our results indicate that it is possible to select grandparent roosters with better reproductive performance.
摘要：
这项研究的目的是分析合适的遗传模型和选择指数，以估计泰国本地公鸡的遗传参数和育种值。共有3475个精液性状的记录(群众运动，精液pH值,精液颜色,volume,精子活力，精子异常,和精子浓度）分析了242只泰国本地祖父母公鸡。使用具有五个协方差函数的多性状随机回归测试日模型来分析方差分量，遗传参数，和育种价值。计算选择指数（SI）以确定不同选择百分比的最佳遗传值。结果表明，具有二阶Legendre多项式函数的多性状随机回归测试日模型是最适合该种群的遗传模型。估计的遗传力值是低到中等，范围从0.110到0.112(质量运动)，0.040至0.051（精液pH），0.092至0.097（精液颜色），0.220至0.225（精液体积），0.067至0.083（精子活力），0.086至0.099（精子异常），和0.134至0.138(精子浓度)。重复性值超过遗传力值，在0.133~0.688范围内。精液性状之间的遗传相关性在-0.332至0.677之间，表型相关性在-0.260至0.460之间。当考虑遗传力和遗传相关值时，精液体积,精子浓度,和群众运动是作为选择指数计算的三大优先精液性状。最后,推荐选择索引的前10%用于创建下一代。我们的发现提供了有关遗传参数的有用信息以及精液性状的适当选择指数，可用于选择泰国本地祖母鸡的遗传。此处报道的精液性状的遗传力估计表明，通过遗传评估方法对选择有足够的反应。我们的结果表明，有可能选择具有更好繁殖性能的祖父母公鸡。
