Effect of carbon dioxide on the survival of ram spermatozoa frozen by the pellet method.
Two experiments were conducted to examine the effect of carbon dioxide (CO2 gas) on the survival of ram spermatozoa frozen by the pellet method. Frozen-thawed semen was flushed with CO2 gas for various periods and the motility of spermatozoa after thawing was investigated. The longer periods for more than 135 seconds of CO2 gas treatment significantly (P<0.01) depressed the motility of spermatozoa after thawing. However, flushing with CO2 gas for less than 90 seconds did not affect the motility. It appears that flushing with CO2 gas for a limited time, 90 seconds at the time of insemi-nation could be effectively utilized for the rapid method of non-surgical intrauterine in-semination with frozen-thawed semen in sheep.