Effect of low temperature thawing procedure and post-thaw cold shock on frozen bull semen

Abstract

The objective of this study was to investigate the effect of low temperature thawing and post-thaw cold shock application on sperm motility, as well as acrosomal and plasma membrane integrities of cryopreserved bull semen. Frozen semen was thawed in a water bath at 5-7 degrees C for 30, 60 or 90 s (low thawed groups), cold shocked (at 5-7 degrees C for 30, 60, 90 s) after thawing at 37 degrees C for 30 s (cold shocked groups), cold for 30 s (control group). The thawing procedure affected the percentages of motile spermatozoa (P < 0.001)and damaged acrosome (P < 0.001) while the bull factor affected the percentages of motile spermatozoa (P < 0.01) and damaged acrosome (P < 00.01). However, swollen tail spermatozoa rates were not affected by the the two factors. There was a significant interaction between thawing procedures and bulls in terms of the studies sperm parameters (P < 0.001). In conclusion, the percentages of motility, intact acrosome and swollen tail spermatozoa of the control group were higher than low-temperature thawed and post-thaw cold-shocked groups. These results indicate that frozen spermatozoa are significantly sensitive to lower temperature not only before but also after thawing.