Indian Journal of Small Ruminants (The)

A study was carried out to evaluate the effect of different equilibration periods on the postthaw seminal traits of buck semen collected at weekly intervals from the adult Jamunapari bucks (2–3 years old), maintained under intensive system of management at Central Institute for Research on Goats, Makhdoom. A total of 17 ejaculates were processed for freezing having the volume ≥ 1.0 ml and mass activity of +4.0 and above. The ejaculates were processed for conventional freezing in two step dilution to maintain the final dilution rate of 1: 10 having 6% glycerol and 10% egg yolk levels. The samples were kept for 4 h in cold handling cabinet and at each hour of equilibration period (1, 2, 3, 4 h), samples were packaged in 0.25 ml French mini straws and frozen in horizontal vapour freezing. Pre-freeze/equilibration progressive motility, live and total abnormal sperm count were done at the end of each h of equilibration period. Then samples were thawed at 40°C for 45 sec after 24 h of storage and the post-thaw progressive motility, live and total abnormal sperm count were carried out. The pre-freeze and post-thaw progressive motility at 1, 2, 3 and 4 h of equilibration periods were 83.24±1.05 and 30.59±2.42, 81.76±0.85 and 31.47±1.76, 74.71±1.39 and 33.24±2.10, 70.59±1.28 and 28.82±1.99%, respectively. The respective values for live sperm count were 88.44±1.21 and 46.02±2.83, 80.85±5.36 and 41.95±1.56, 81.90±2.06 and 43.57±3.53, 80.37±2.32 and 41.01±3.02%. The total abnormal sperm ranged from 0.91 to1.74% before freezing and 2.18 to 2.84% after freezing at different hours of equilibration periods. The pre-freeze progressive motility up to 2 h of equilibration period varied significantly (P<0.05) with 3 and 4 h of equilibration periods. The remaining characteristics did not show any significant variation between different hours of equilibration periods. Therefore, equilibration period of 3 h may be followed in the freezing protocol used for buck semen cryopreservation as equilibration period of 2 or 3 h showed superiority over 1 or 4 h in terms of post-thaw spermatozoan characteristics in frozen-thawed Jamunapari buck semen.