Fertility of deep frozen boar spermatozoa at various intervals between insemination and induced ovulation: influence of boars and thawing diluents.

TLDR: The present results indicate that spermatozoa with low resistance to freezing-thawing have a short fertile life in the female genital tract after insemination.

Abstract: The fertilizing ability of deep frozen boar spermatozoa was assessed after artificial insemination at various intervals after human chorionic gonadotropin (HCG) induced ovulation in gilts. Boar seminal plasma and OLEP were used as thawing diluent agents. The fertilization rates were similar when insemination was performed 2 or 6 hours before the time of estimated ovulation (40 hours post-HCG administration). However fertility rates markedly declined when insemination was performed earlier than 6 hours before expected ovulation. In inseminations performed 2 hours before ovulation the fertility rate was higher with specimens treated with boar seminal plasma diluent than with OLEP. As the difference between the time of insemination and that of ovulation increased the difference in fertilizing ability of spermatozoa from the 2 boars used also increased. The results show that spermatozoa which have a low resistance to freezing-thawing also have a diminished fertile life in the female genital tract.