Abstract: It was aimed to investigate the effects of different concentrations (0.05,0.1,0.2,0.5,1,5,10 μmol/L) of calcium ionophore (A23187,IA) and 2 mmol/L caffeine on the ovine sperm capacitation in vitro.The results showed that the higher rate of capacitation in vitro， lower the rate of acrosome reaction(AR), and the lower sperm motilily were induced by the high concentration of IA, but the dead sperm could be increased. The capacitation and AR of ovine sperm in vitro were not affected even delaying time. Caffeine could promote IA to induce AR. Collectively, this might be recommol/Lended that it be applicable for improving ovine capacitation in vitro with 0.05 to 0.2 μmol/L IA for 1 min. 

Key words: ovine sperm; capacitation in vitro; calcium ionophore; caffeine