Abstract
The aim of this study was to assess the effect of cooling on sperm motility before and after frozen-thawed stallion semen. Fifteen ejaculates of three stallions were collected with artificial vagina. The progressive motility was determined under microscope immediately after collection, cooling (5°C for 0, 2, 7 or 24 h) before frozen-thawed and cooling (5°C for 0, 2, 7 or 24 h) after the semen was frozen-thawed. Sperm progressive motility (83.1, 78.7, 74.8 or 70.3%, respectively) was significantly different (P<0.05) at different hours of cooling before freezing. Similar pattern was found when semen was subjected to cooling, frozen-thawed and cooling time resulted in a progressive reduction in motility from 39.4 to 26.9%. The motility of semen subjected only to cooling for 24 h before freezing was optimal (70.0%) for artificial insemination. Moreover, semen subjected to cooling for 7 or 24 h before and after frozen-thawed could be used still with some considerations for artificial insemination.
Key words: Stallion, semen, motility, cooling, frozen-thawed
