Non-genetic factors analysis and genetic parameter estimation of sperm motility parameters in Duroc pigs

【Objective】The non-genetic factors analysis and genetic parameters estimation of sperm motility parameters of Duroc pigs were carried out to provide reference for improving semen quality of Duroc boars and breeding level of sows.【Method】A total of 178706 sperm motility parameters［sperm concentration（SC），sperm straight-line motility rate（SLMR），curvilinear distance（DCL），average path velocity（VAP），curvilinear velocity（VCL）and straight-line velocity（VSL）］were collected from 570 Duroc boars from 2016 to 2023. The analysis of fixed effect variance，statistical analysis，non-genetic factor analysis，estimated variance component analysis，genetic correlation analysis and phenotypic correlation analysis were performed for different motility parameters of Duroc porcine sperm.【Result】The kinetic parameters of sperm were extremely significantly affected by month of age at sperm collection，year of birth，birth parity，year of sperm collection，litter size and season of sperm collection（P<0.001）. The variation coefficient of SLMR was the smallest，6.20%，and its average was 91.49%. The variation coefficient of SC was the maximum，being 51.99%. The DCL，VAP，VCL and VSL of Duroc boars of >24 months of age were significantly higher than those of other Duroc boars of other months of age（P<0.05，the same below），and the SC of Duroc boars born in 2022 and 2021 was significantly higher than that of other birth years. The SLMR，DCL，VAP，VCL and VSL of Duroc boars at 3 to 4 parities were significantly higher than those of other parities. The SC，SLMR，DCL，VAP，VCL and VSL of Duroc boars with > 16 litter size were significantly higher than those of other litter sizes. SLMR，DCL，VAP，VCL and VSL of Duroc boars were significantly higher in winter than in other seasons，and significantly lower in summer. The heritability of each motility parameter of Duroc boar sperm ranged from 0.040 to 0.240. The repetition force was 0.26-0.38. The heritability of SC and SLMR was <0.100，belonging to low heritability trait，and the repeatability of VAP and VSL was higher，being 0.33 and 0.38 respectively. The genetic correlation coefficients between SLMR and DCL，VAP，VCL and VSL were 0.38，0.51， 0.41 and 0.41 respectively. Phenotypic correlation coefficients were 0.29，0.30，0.25 and 0.26 respectively. The reliability of the estimated breeding values of SC，SLMR，DCL，VAP，VCL and VSL of Duroc boar sperm were 0.79，0.59，0.73， 0.80，0.75 and 0.82 respectively，and the reliability of each motility parameter was high.【Conclusion】Sperm motility parameters are significantly affected by month of age at sperm collection，year of birth，birth parity，year of sperm collection，litter size and season of sperm collection. Sperm concentration and sperm straight-line motility rate are low heritability traits，and sperm straight-line motility rate，curvilinear distance，average path velocity，curvilinear velocity and straight-line velocity have high genetic correlation.