Seasonal changes in sperm parameters of British milk rams.

Seasonal changes in the sperm parameters of British Milk rams were studied at weekly intervals over a period of 12 months. By comparing the seasonal averages of the test parameters, significant differences were determined in several cases. Substantial differences were found in the averages of quantitative parameters between autumn and the other seasons. As regards the qualitative parameters, the results obtained in summer and autumn were significantly different from those measured in winter and spring. The ratio of deformed spermatozoa was outstandingly high (22.72%) in August. A close negative correlation was established between sperm motility and the incidence of acrosomal defects (r = -0.52; P < 0.1%). The length of natural daylight and daily average temperature were found to exert an influence on the sperm parameters. In autumn, the combined effect of the two weather parameters shows a significant correlation with the concentration of spermatozoa (r = -0.62; P < 0.1%). As British Milk rams show well-balanced sperm production throughout the year with only minor fluctuations, they can be used for reproduction all the year round.