Hyaluronidase Relationships in Dairy Bull Semen

Abstract

100 semen samples from 22 dairy bulls (including Guernsey, Brown Swiss and Holstein) were assayed for hyaluronidase within 1 hr. after ejaculation and again after incubation for 24 hrs. at 37[degree]C. Analysis of variance indicated that, although there were no significant differences among the breeds in hyaluronidase levels (either initial or after 24 hrs.), there were highly significant differences among individual bulls. However, when adjustment was made for the effect of sperm concn. through the analysis of covariance, there were no significant differences among bulls in respect to the 24-hr. hyaluronidase levels, whereas thd initial hyaluronidase levels still showed highly significant differences. Correlation coeffs. between seminal hyaluronidase levels (both initial and 24-hr. assays) and the following semen characteristics were detd.: undiluted semen: sperm concn., 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 concn.) 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.