Effect of Different Freezing Frequency and Thawing Temperature on Cryopreservation of Boar Semen

For improving the freezing and de-freezing methods for boar semen further,it was aimed to investigate the effect of different freezing frequency(-100 ℃ 10 min,-120 ℃ 10 min,-140 ℃ 10 min) and thawing temperature(37 ℃ 30 s,45 ℃ 30 s,52 ℃ 30 s,60 ℃ 30 s) on cryopreservation of boar semen.The results showed that the sperm motility,plasma integrity,normal acrosome rate by freezing treatment with-120 ℃ 10 min,were all significantly higher than those of the other three groups respectively(P0.05).The sperm motility,plasma integrity,normal acrosome rate by thawing treatment with 37 ℃ 30 s,were not significantly higher than those of the other three groups respectively(P0.05),but the difference of the sperm abnormality in the treatment with 60 ℃ 30 s was significant(P0.05),but with 45 ℃ 30 s and 52 ℃ 30 s were not significant(P0.05).Therefore,it could be concluded that the combination of freezing by-120 ℃ 10 min and thawing by 37 ℃ 30 s were appropriate to frozen-thawed 0.25 mL pipettes of boar semen.