The effect of heat stress on sperm parameters and sex ratio of Y or X- bearing spermatozoa after goat semen cryopreservation

Pre-sex selection is the process by which Y or X-bearing spermatozoa are used to produce the desired sex in the offspring. X-bearing spermatozoa are believed to have a longer lifespan, and are more resistant to acidic conditions, temperature changes, and even oxidative stress compared to Y-bearing.

The present study was aimed to investigate the effect of heat stress on sperm parameters and sex ratio of sperm containing X or Y chromosome after freezing-thawing of goat semen. The diluted semen of the heat stress group was first placed at 43 ° C for 30 minutes and then frozen-thawed as in the control group.

The results showed that heat stress led to a significant reduction in the overall sperm motility, viability and sperm cell membrane integrity compared to the control group. Also, in the heat stress group, the mean Y to X ratio was 94.4%, which showed a significant difference (p <001) compared to the expected Y to X ratio of 1.

Applying heat stress to sperm in vitro can lead to a significant reduction in sperm parameters. In addition, the decrease in the number of Y-bearing spermatozoa in the survived population post thawing, may indicate that the Y-bearing spermatozoa are more sensitive and fragile compared to X-bearing spermatozoa in goat species. Keywords: Sex determination, Cryopreservation, Heat stress, Goat sperm