The effect of season on semen parameters in crossbred boars and phenotypic correlations between semen characteristics in different seasons

Abstract

The study evaluated ejaculates of cross-bred boars produced by reciprocal crossbreeding of the breeds Duroc and Pietrain, as well as the effect of the season of the year on qualitative and quantitative parameters of the semen of these boars. Phenotypic correlations between semen characteristics in particular seasons of the year were estimated as well. The analysis included a total of 1156 ejaculates from 2-year-old boars, collected manually at 3-4-day intervals. The following traits were evaluated: ejaculate volume (ml), sperm concentration (x106 x ml-1), percentage of live sperm (showing progressive motion) (%), total number of live sperm in the ejaculate (in billions), number of sperm per insemination dose, and the number of insemination doses obtained from one ejaculate. No significant differences were noted in the semen characteristics of boars produced by reciprocal cross-breeding of the Duroc and Pietrain breeds. The season of the year significantly affected the characteristics of the ejaculates. Ejaculates collected in the spring had the greatest volume, while the highest sperm concentration and sperm count were noted in the ejaculates collected in the autumn and winter. The volume of the ejaculates decreased substantially in the summer, together with the sperm count, resulting in fewer insemination doses obtained per ejaculate. The value of the phenotypic correlations between semen characteristics was not significantly affected by the season of the year.