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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.

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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.

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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.

Artificial insemination (AI) was developed as a technique for effectively distributing gametes from males of high genetic merit while avoiding movement of animals between herds, and inter-animal contact. However, potential pathogens can be spread between animals in semen. Semen from healthy animals frequently contains bacteria that contaminate the ejaculate during semen collection and processing. Antibiotics are added to semen extenders used to prepare semen doses for artificial insemination (AI), to

A study was carried out to study the effect of freezing on cryosurvival of yak semen. Artificial insemination in yak is still in infancy. Semen cryopreservation and use of artificial insemination can be applied in yak husbandry for conservation and rapid multiplication of superior germplasm. Semen was collected from four adult yak bulls using artificial vagina method managed under uniform conditions. A total of 40 ejaculates comprising of 10 ejaculates each bull were collected following twice a week schedule and evaluated for fresh semen characteristics. The fresh yak semen characteristics viz. ejaculate volume (ml), mass activity (0-4), initial sperm motility (%), sperm concentration (x 10 6 /ml), live sperm (%), sperm abnormality (%) and intact acrosome (%) were 3.10 ± 0.18, 3.53 ± 0.96, 83.89 ± 2.87, 1180.22 ± 42.32, 77.63 ± 4.23, 8.45 ± 3.33 and 93.61 ± 3.78 respectively. The ejaculates were diluted (1:10) with Tris extender consisting of 6.4 ml glycerol and 20 ml of fresh egg yolk. Straws were equilibrated at 5°C for 4 hours followed by exposure to liquid nitrogen vapour for 10 minutes and finally transferred to liquid nitrogen container for storage. The cryosurvival rate was studied after 7 days of storage in liquid nitrogen. The frozen semen was thawed in warm water (37°C) for 30 seconds for evaluation. Mean values of postthaw sperm motility (%), live sperm (%) and intact acrosome (%) in yaks were 55.67 ± 4.67, 65.62 ± 3.23 and 89.26 ± 3.67 respectively. In conclusion, yak semen has a better cryosurvival while freezing in tris extender with 6.4 per cent glycerol and 20 per cent egg yolk following an equilibration period of 4h.