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Aim:To evaluate different thawing temperatures and duration on the post-thaw semen quality of Indian yaks bulls.Materials and Methods:Semen ejaculates from four different yak bulls were collected using artificial vagina method and extended with tris extender containing 6.4% glycerol at 35°C, cooled gradually from 35°C to 5°C at 1°C/3 min and equilibrated at 4-5°C for 4 h and frozen in French mini straws using a programmable bio-freezer and finally stored in liquid nitrogen. Thawing of frozen semen straws was carried out using three methods i.e., 35°C for 60 s (thawing method I), 37°C for 30 s (thawing method II) and 75°C for 9 s (thawing method III). The post-thaw semen quality parameters assessed were sperm motility, percent live sperm, hypo-osmotic swelling test (HOST)-reacted sperm, acrosomal changes, and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in the extracellular media.Results:The percent sperm motility, total incidence of acrosomal changes, and extracellular release of AST varied significantly (p<0.01) between thawing methods but live sperm and HOST-reacted sperm did not vary significantly between thawing methods. The percent sperm motility of frozen yak semen for thawing method III was significantly (p<0.05) higher than that for thawing methods I and II, the difference between thawing methods I and II being non-significant. The critical difference test revealed that the total incidence of acrosomal changes and extracellular release of AST were significantly (p<0.05) lower when thawing was done using methods I and II than in method III.Conclusion:On the basis of the present experiment, we can conclude that barring the post-thaw sperm motility, thawing of frozen yak semen in water either at 35°C for 60 s or 37°C for 30 s gives better post-thaw semen quality than at 75°C for 09 s.

The aim of this study was to evaluate heparin-induced in vitro capacitation-associated changes in spermatozoa of swamp buffalo. Therefore, freshly ejaculated and washed spermatozoa of 8 swamp buffalo bulls were capacitated in vitro in TALP medium supplemented with BSA, heparin, and HEPES buffer at a concentration of 6 × 10 9 spermatozoa/mL at 37 °C for 6 h. Capacitation status of spermatozoa in terms of the hyperactivated motility, acrosome membrane integrity, total hypoosmotic swelling test (HOST), activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and sperm membrane protein (SMP) and cholesterol content were estimated for each ejaculate at 1-h intervals from 0 to 6 h of incubation. The results revealed that the highest hyperactivation of spermatozoa (74.50 ± 1.78%) and live acrosome reaction (56.92 ± 1.88%) was recorded at 4 h of incubation while the total HOSTreacted spermatozoa and SMP and cholesterol levels decreased significantly (P < 0.01) with increasing period of incubation. The AST and ALT activities increased significantly (P < 0.01) as incubation period increased. In conclusion, heparin induces in vitro capacitation changes in swamp buffalo spermatozoa as evidenced by the highest hyperactivation of spermatozoa and live acrosome reaction at 4 h of incubation.

Assam Hill goat (AHG) is an important goat germplasm found in Assam and its adjoining areas of India. The study was designed with an objective to study the semen characteristics and freezability of AHG buck semen using Tris -Egg yolk-Citrate-Fructose diluent. The mean values of fresh semen characteristics in AHG bucks viz., ejaculate volume (ml), initial sperm motility (%), sperm concentration (x106/ml), live sperm (%), sperm abnormality (%), HOST-reacted sperm (%) and intact acrosome (%) recorded were 0.39 ± 0.01, 77.97 ± 0.73, 3201.00 ± 143.78, 83.02 ± 0.65, 7.66 ± 0.73, 66.95 ± 0.74 and 93.34 ± 0.51, respectively. Mean values for post-thaw semen characteristics i.e., sperm motility (%), live sperm (%), HOST-reacted sperm (%) and intact acrosome (%) were 55.39 ± 0.97, 71.01 ± 0.78, 54.77 ± 0.55 and 82.16 ± 0.43, respectively. It can be concluded that AHG bucks donate acceptable quality of semen which can be frozen successfully in Tris-Egg yolk-Citrate-Fructose diluents for using in Artificial Insemination.