Effect of seminal plasma, egg yolk, and season on the freezability of Saanen buck semen

Abstract

This study was to find out whether removal of seminal plasma and different egg yolk concentrations in a freezing extender reveals any effect of season on the freezability of Saanen buck semen, Semen was collected from four Saanen bucks during the breeding and non-breeding seasons. Ejaculates (more than 1 ml) with three or more mass motility, >70% initial motility, and at least >2x10(9) spermatozoa/ml were pooled. The pooled semen was firstly divided into two main groups according to removal and not removal of seminal plasma. Then each main group was divided into three subgroups according to different egg yolk concentrations. The semen was used in a Tris-based freezing extender with 6%, 12% or 18% egg yolk. 0.25 ml of straws were frozen in liquid nitrogen vapour. Motility, dead spermatozoa, defected acrosome, and other morphological defects (OMD) were evaluated in equilibrated at 5 degrees C and post-thawed semen. There were seasonal differences in the semen for motility, dead spermatozoa, and OMD. For 5 degrees C equilibrated and post-thaw semen, the presence of buck seminal plasma had a detrimental effect on motility and dead spermatozoa. On the other hand, 18% egg yolk concentration affected post-thaw semen motility (P<0.05). In conclusion, the removal of seminal plasma improved motility following the freezing-thawing procedure in the breeding and the non-breeding seasons. The results of this study showed that the breeding season and removal of seminal plasma had beneficial effects on the freezability of Saanen buck semen.