Effect of thaw rates on survival of buffalo spermatozoa frozen straws.

Eighteen ejaculates from three buffalo bulls of Nili-Ravi breed were tested in a 3 X 6 X 3 factorial experiment. Semen was extended in lactose-fructose-egg yolk-glycerol extender containing penicillin (1000 IU/ml) and streptomycin (1000 micrograms/ml). Semen was frozen in .5-ml polyvinyl chloride straws in liquid nitrogen vapor and stored in liquid nitrogen for 24 h. Straws were thawed at water bath temperatures of 0, 37, or 75 degrees C for 2 min, 15 s, and 9 s, respectively. At thawing bath temperature of 0, 37, or 75 degrees C, percentage of motile spermatozoa averaged 30, 40, and 50%. Differences were significant between thaw rates for initial postthaw motility, postthaw sperm survival at 37 degrees C, and absolute index of survival of spermatozoa. Bulls were also different for initial postthaw motility, postthaw sperm survival at 37 degrees C, and absolute index of survival of spermatozoa. Thaw rate of 75 degrees C for 9 s was superior to other rates.