Effect of different thawing methods on post-thaw motility of cow semen in cryopreservation straws

The study compared the effects of different thawing temperatures(5,15,40,75,90℃) and times(1120 s) on properties of post-thaw cow semen by detecting frozen-thawed semen motility,acrosome integrity and tail membrane integrity.The results showed that motile spermatozoa rate of frozen semen thawed at 75℃ for 3 s was the highest.A similar result was observed under thawing at 40℃ for 20 s.Under 5℃ and 15℃ thaw sperm motility was lower.Sperms defrosted at 90℃,the acrosome integrity and tail membrane integrity were significantly lower than those at 40℃(P 0.05) and 75℃(P 0.01),and the sperm deformity rate was significantly higher than that treated at 40℃ and 75℃(P 0.05).With the increasing of thawing temperature,the sperm effective survival time at 37℃ showed significant difference as 40℃ 75℃ 90℃.In conclusion,it was recommended that the frozen semen thawing at 75℃ for 3 s could be used for artificial insemination immediately.When a large number of cows need to be inseminated or thawed semen could not be inseminated immediately,in order to keep the sperm vitality for a longer time,the frozen semen thawing at 40℃ for 20 s would be suitable.