Discipline: Veterinary Medicine
This study was undertaken to examine the morphology of frozen bubaline spermatozoa subjected to different equilibration time and then thawed at various thawing temperature and time. Four semen samples collected from each of three Murrah buffalo bulls were diluted in a Tris-egg yolk extender with 7% ethylene glycol. The diluted samples were equilibrated at 20, 40 and 60 min, packaged into 0.5 ml French straws, suspended in liquid nitrogen vapor for 7 min, then stored in liquid nitrogen at -196°C for 7-14 days. After storage, the spermatozoa were thawed at 37°C, 41°C or 45°C for 12 or 17 sec. Semen subjected to 40 min equilibration time and thawed at 37°C for 17 sec or at 41°C for 12 sec had lower total sperm abnormality percentage than semen equilibrated for 20 and 60 min and subjected to the same thawing temperature and time. A comparable low abnormality percentage was also observed for semen equilibrated for 20 min thawed at 41°C for 17 sec. There was a significantly higher percentage of tertiary sperm abnormality for semen equilibrated for 20 min and thawed at 37°C for 12 sec compared to other treatment groups. Shortening the equilibration time to 40 or 20 min and thawing at 41°C for 12 or 17 sec generally resulted to low total percentage sperm abnormality.