Estimation of the genetic parameters of semen quality in Beijing-You chickens

By estimating the genetic parameters of various semen quality traits in Beijing-You chickens, this study aims to elucidate the inheritance patterns of these traits and the correlations between them to facilitate setting up appropriate breeding strategies for enhanced semen quality. Semen samples were collected from 518 Beijing-You roosters at 43 wk of age from 3 selection lines related to meat flavor traits. Seven semen quality traits, consisting of semen volume, pH, and color, and sperm viability, motility, percent deformity, and concentration, were determined. Sizeable variations (18-24% CV) were observed for all traits, except for semen pH. The effects of semen collection time and origin of the chickens (line) were analyzed to optimize the proper models for estimating genetic parameters for each trait. The multiple-trait derivative-free restricted maximum likelihood method was used for estimating variance components. The results revealed that sperm viability, motility, and percent deformity exhibited high heritabilities (h(2) = 0.52, 0.85, and 0.60, respectively). Semen volume, semen color, and sperm concentration had moderate heritabilities (h(2) = 0.28, 0.19, and 0.12, respectively). Semen pH showed low heritability (h(2) = 0.03). Genetic and phenotypic correlations between sperm motility and viability were positive and high (rA = 0.88 and rP = 0.59). In addition, these 2 traits were genetically negatively correlated with percent deformity. This implied the possibility of reducing sperm deformity, which is difficult to measure, by indirect selection. It is concluded from this study that semen quality can be improved by selection. The traits with high variations and heritabilities such as semen volume are promising traits for selection to improve semen quality and likely reproductive performance of native chicken breeds.