Impact of three field-practical thawing methods on bovine semen motility, viability, and membrane and acrosome integrity at 0 and 2 hours post-thaw

Abstract

The effectiveness of artificial insemination with frozen semen depends largely on semen quality, which can be influenced by the thawing method. This study evaluated the effect of three field-practical semen thawing methods on bovine sperm motility, viability, and plasma membrane and acrosome integrity at 0 and 2h post-thaw. The treatments were: T1 (water at 37 °C), T2 (axilla at 36.1°C), and T3 (room temperature at 23.4 °C). A total of 42 frozen semen straws was analyzed. Motility was assessed using a CASA system, viability was evaluated with Hoechst/propidium iodide staining, and plasma membrane and acrosome integrity were examined using the hypoosmotic swelling (HOS) test and Coomassie blue (CB) staining, respectively. Statistical analysis included ANOVA and t-tests. At 0h, thawing using a water bath (T1) or the axilla (T2) resulted in higher (P < 0.05) total motility, progressive motility, rapid motility, and number of rapidly motile sperm compared to thawing at room temperature (T3). Thawing using a water bath also resulted in higher (P<0.05) sperm viability and percentage of HOS+/CB+ cells at 0h than thawing with T2 or T3. At 2h, post-thaw, T1 resulted in superior (P<0.05) total motility, progressive motility, rapid motility, and viability compared with T2 and T3 thawing methods. Holding samples from 0 to 2h reduced sperm quality parameters in all three thawing methods. In conclusion, thawing semen in warm water at 37 °C yielded better sperm quality parameters at both 0 and 2h post-thaw than thawing in the axilla or at room temperature.