Seasonality and freezability vs routine parameters in stallion semen

Abstract

The fertilizing ability of stallion semen was analyzed using fresh and frozen samples, obtained before (June-July) or during (October-November) the breeding season. Thirty ejaculates obtained from 4 stallions, were used. The analysis comprises routine seminogram; ATP concentration (Comhaire et al., 1983); subjective and objective motility and sperm velocity (Makler, 1980). Freezing was done following the technique of Martin et al. (1979). Sperm velocity, ATP content and objective motility in ejaculates of subjective motility >50% show values of 14.0 ± 0.84 μm s-1; 4.8 ± 2.7 x 10-7 M and 54.0 ± 7.4%, respectively. For ejaculates with subjective motility <50%, these values are 8.4 ± 2.4; 0.74 ± 0.36 x 10-7 M and 27.0 ± 0.8%. No significant changes in these characteristics were elicited by freezing, though ATP content dropped to 50% after thawing. These characteristics are highly associated between them (p < 0.05) and with some conventional parameters of the routine seminogram such as spe