Twelve sexually mature buffalo bulls, were used in the present study. The experimental work was carried out to study the effects of removal of seminal plasma by centrifugation and addition of different concentrations of caffeine (0,2,4 and 8mM/100ml) to the extended cooled buffalo semen with lactose-yolk citrate (LYC) extender on biophysical (percentage of sperm motility, dead spermatozoa, sperm abnormalities and acrosomal damage) and biochemical (aspartate-aminotransferase: AST, alanine-aminotransferase: ALT and alkaline phosphatase: ALP) changes, during chilled storage at 50C for up to 6 days and incubation at 370C for up to 2 hours. The conception rates of buffalo-cows artificially inseminated with fresh semen and washed cooled semen supplemented without or with 2mM caffeine, were also assessed.
The results showed that, removal of seminal plasma by washing of buffalo semen showed significantly (P<0.05) higher the percentage of sperm motility and significantly (P<0.05) lower the percentages of dead spermatozoa, sperm abnormalities and acrosomal damage of spermatozoa than the non-washed semen. Supplementation of 2 or 4mM caffeine to the extended cooled semen either washed or non-washed increased significantly (P<0.05) the percentage of sperm motility, while decreased significantly (P<0.05) the percentages of dead spermatozoa, sperm abnormalities and acrosomal damage of spermatozoa as compared to 8mM caffeine or free-caffeine medium. The storage at 50C for up to 6 days or incubation at 370C for up to2 hours of the extended cooled buffalo semen either washed or non-washed decreased significantly (P<0.05) the percentage of sperm motility, while it increased significantly (P<0.05) the percentages of dead spermatozoa, sperm abnormalities and acrosomal damage of spermatozoa. Removal of seminal plasma by washing of buffalo semen the extended decreased significantly (P<0.05) the leakage of AST, ALT and ALP enzymes into the extracellular medium as compared to the non-washed semen. Supplementation of 2, 4, or 8mM caffeine to the extended cooled either washed or non-washed buffalo semen decreased significantly (P<0.05) the amounts of AST, ALT and ALP enzymes released into the extracellular medium as compared to free-caffeine medium. The storage at 50C for up to 2 days or incubation at 370C for up to 2 hours of the extended cooled buffalo semen either washed or non-washed increased significantly (P<0.05) the amounts of AST, ALT, and ALP released into the extracellular medium. The conception rates of the buffalo-cows artificially inseminated with fresh extended semen with LYC extender or washed cooled semen supplemented with 2mM caffeine was insignificantly higher than the washed cooled semen free-caffeine.