Main and reciprocal crossbred cocks from a population of ۵۳۱ day-old chicks were used to study
heritability of
semen volume (SV), sperm motility (SM), sperm concentration (SC) and live sperm (SP) at ۳۶ and ۴۰ weeks of age. Analysis of variance was performed for unbalanced nested design. The analysis yielded
variance components of sire ( ), dam ( ) and sire plus dam ( ), and
heritability (h۲) of the traits was estimated therefrom. The estimates ranged from ۱.۳۳ to ۰.۰۲ and ۱.۴۸۱ to ۰.۰۳; ۱.۴۸ to ۰.۱۰ and ۰.۹۶ to ۰.۰۸; ۰.۹۷ to ۰.۱۲ and ۰.۸۹ to ۰.۰۴ at ۳۶ and ۴۰ weeks for SV, SM, SC and LS, respectively. Estimates from , and ranged from ۱.۴۸ to ۰.۰۲, ۱.۰۴ to ۰.۰۳ and ۰.۸۵ to ۰.۰۶ ; ۱.۱۰ to ۰.۰۴, ۱.۲۱ to ۰.۱۸ and ۰.۹۰ to ۰.۰۵; ۰.۹۶ to ۰.۰۹, ۱.۴۸ to ۰.۰۱and ۰.۷۶ to ۰.۱۰; ۰.۹۷ to ۰.۰۴, ۰.۸۹ to ۰.۱۲ and ۰.۶۹ to ۰.۰۸ for the four traits, respectively. Large additive genetic variances existed for most of the
semen quality traits, especially the live sperm from sire and sire plus dam
variance components of the reciprocal
crosses at ۴۰ weeks. These traits were highly heritable and could be improved by individual selection.Main and reciprocal crossbred cocks from a population of ۵۳۱ day-old chicks were used to study
heritability of
semen volume (SV), sperm motility (SM), sperm concentration (SC) and live sperm (SP) at ۳۶ and ۴۰ weeks of age. Analysis of variance was performed for unbalanced nested design. The analysis yielded
variance components of sire ( ), dam ( ) and sire plus dam ( ), and
heritability (h۲) of the traits was estimated therefrom. The estimates ranged from ۱.۳۳ to ۰.۰۲ and ۱.۴۸۱ to ۰.۰۳; ۱.۴۸ to ۰.۱۰ and ۰.۹۶ to ۰.۰۸; ۰.۹۷ to ۰.۱۲ and ۰.۸۹ to ۰.۰۴ at ۳۶ and ۴۰ weeks for SV, SM, SC and LS, respectively. Estimates from , and ranged from ۱.۴۸ to ۰.۰۲, ۱.۰۴ to ۰.۰۳ and ۰.۸۵ to ۰.۰۶ ; ۱.۱۰ to ۰.۰۴, ۱.۲۱ to ۰.۱۸ and ۰.۹۰ to ۰.۰۵; ۰.۹۶ to ۰.۰۹, ۱.۴۸ to ۰.۰۱and ۰.۷۶ to ۰.۱۰; ۰.۹۷ to ۰.۰۴, ۰.۸۹ to ۰.۱۲ and ۰.۶۹ to ۰.۰۸ for the four traits, respectively. Large additive genetic variances existed for most of the
semen quality traits, especially the live sperm from sire and sire plus dam
variance components of the reciprocal
crosses at ۴۰ weeks. These traits were highly heritable and could be improved by individual selection.