Effects of seasons on enzymatic changes and cholesterol efflux in relation to freezability in Tharparkar bull semen

To assess the effect of different seasons on sperm motility, viability, total sperm abnormality, acrosomal and plasma membrane integrity, antioxidant profiles such as superoxide dismutase (SOD) and catalase (CAT), enzymatic profiles such as aspartate amino transaminase (AST), lactic acid dehydrogenase (LDH) and biochemical profiles such as total cholesterol in Indian breed, Tharparkar bull. Total numbers of 60 ejaculates from 3 bulls were collected through artificial vagina method twice a week during summer and winter season (30 ejaculates from each season). The semen samples were pooled and diluted with the standard TEYC extender and these seminal, biochemical parameters were studied at fresh, pre- freeze and post thaw stage of semen cryopreservation. Seminal parameters such as volume, plasma membrane integrity and biochemical parameters such as SOD at fresh semen, acrosomal integrity, LDH, AST and total cholesterol at pre–freeze level and acrosomal integrity, SOD at post thaw stage of cryopreservation were differed significantly (P< 0.05) between the seasons. But most of other seminal, biochemical parameters showed no significant difference between the seasons in this pride bull. Forward progressive motility was positively correlated significantly with livability (P< 0.01), acrosomal (P< 0.01) and plasma membrane (P< 0.01) integrity and negatively correlated significantly with total sperm abnormality (P< 0.05) at fresh, pre- freeze and post thaw stage of cryopreservation of semen in both winter and summer seasons. Similarly Forward progressive motility was positively correlated significantly with SOD (P< 0.05) at pre- freeze level in winter season and at fresh semen in summer season and negatively correlated significantly with AST (P< 0.05) at fresh semen in winter season. It can be concluded that cryopreservation of Tharparkar bull semen in summer and winter season do not show any definite pattern in relation to seminal and biochemical profile changes and the semen can be cryopreserved in both seasons throughout the year in this prestigious Indian breed of cattle.