Hyaluronidase Relationships in Dairy Bull Semen

Abstract

Summary One hundred semen samples from 22 dairy bulls (including Guernsey, Brown Swiss and Holstein) were assayed for hyaluronidase within 1hour after ejaculation and again after incubation for 24 hours at 37° C. Analysis of variance indicated that, although there were no significant differences among the breeds in hyaluronidase levels (either initial or after 24 hours), there were highly significant differences among individual bulls. However, when adjustment was made for the effect of sperm concentration through the analysis of covariance, there were no significant differences among bulls in respect to the 24-hour hyaluronidase levels, whereas the initial hyaluronidase levels still showed highly significant differences. Correlation coefficients between seminal hyaluronidase levels (both initial and 24-hour assays) and the following semen characteristics were determined: undiluted semen: sperm concentration, sperm per ejaculate, semen volume, initial motility, duration of 2 motility and total duration of motility; diluted semen: total duration of motility, initial percentage live sperm and percentage live sperm surviving cold shock. Although many of these zero order correlations were significant or highly significant, when first order partial correlations (independent of sperm concentration) were used, only the negative partial correlations of initial hyaluronidase with initial percentage live sperm and with percentage live sperm surviving cold shock retained significance.