Glycerol Concentration Effects on Quality and Longevity of Post-thaw Goat Semen

This study determined the effects of glycerol concentration (7, 10 and 14 % (v/v)) supplemented into freezing medium on post-thaw sperm qualities. Semen was collected from 3 Black Bengal bucks and then pooled to reduce individual variation. Motility, viability, morphology and acrosome integrity were evaluated before and after cryopreservation. Computer-assisted semen analysis was used to assess sperm motion patterns at 0, 1, 2 and 3 hours post-thawing. The laparoscopic artificial insemination was performed to test the fertilizing ability of frozen-thawed semen. The spermatozoa cryopreserved with 10 % glycerol tended to have a higher percentage of motility, progressive motility, spermatozoa with intact acrosome membrane and live spermatozoa especially when examined at 1 hour after thawing. Motion characteristics in all groups were similar except that the beat cross-frequency of spermatozoa frozen with 14 % glycerol was significantly lower than the 10 % glycerol group (p = 0.0211). The laparoscopic AI using frozen-thawed semen obtained from 10 % glycerol group yielded 60 % (3/5) conception rate and three live offspring. In conclusion, glycerol concentration affects the qualities and longevity of post-thaw goat semen. The freezing medium containing 10 % glycerol sufficiently protected goat spermatozoa against cryoinjury during freezing an