Genetic parameter estimation of semen characteristics and sire selection traits for Bonga sheep under the community-based breeding program

Pursuing the community-based breeding program (CBBP) selection of the breeding sire for Bonga sheep estimated breeding value by six months body weight, testicle size, and physical characteristics were used as selection criteria. A study was conducted to investigate the association of sire selection traits with semen characteristics and to estimate their heritability. Data were collected from a total of 101 adult breeding sires of Bonga sheep. Semen was collected using artificial vagina and processed for semen qualities. The variance components and genetic parameters were estimated using multivariate analysis of animal model using restricted maximum likelihood method of WOMBAT software. Six different animal models were compared for the dataset and best-fit model was selected using Akaike information Criteria (AIC). Direct additive effect (model 1) was the best-fit model for the current dataset. The direct heritability for studied traits were 0.23 ± 0.122, 0.13 ± 0.129, 0.13 ± 0.110, 0.09 ± 0.036, 0.37 ± 0.155, and 0.11 ± 0.162 for semen volume, mass motility, concentration, total spermatozoa, six months body weight, and scrotum circumference, respectively. Moderate heritability of six months body weight and semen volume indicated that further breed improvement through selection is possible. Low heritability of semen characteristics traits indicated that good semen quality could be obtained by improving environmental management of the sire. Both six months body weight and scrotum circumference have high and positive correlation with sperm mass motility, and concentration but negatively correlated with semen volume and total spermatozoa production. Given the strong correlation between semen characteristic qualities, the associated response was anticipated.