Comparison of extenders and storage temperature in chilling canine semen

Abstract

This study aimed to compare the effects a commercial milk-based extender and a self-made egg yolk extender had on the quality of canine semen stored at two different temperatures, 5ºC or 15ºC. The ejaculate obtained was split into two aliquots of equal volume and diluted with the milk or egg yolk extender. The final concentration was 100×106 spermatozoa/mL. Diluted semen was placed in transport containers and maintained at final storage temperatures of 5ºC and 15ºC. The quality of the chilled semen was assessed 12, 24, and 36 hours after storage. Semen diluted with the milk extender had higher motility, vigour, and plasma membrane integrity (p<0.05) of the spermatozoa than that diluted with the egg yolk extender. No difference in the semen quality was observed between the stored temperatures in both the groups. The difference observed between the extenders could be due to the standard formulation of the commercial milk extender and the presence of glucose in the mixture. In conclusion, the milk extender was better than the egg yolk extender at preserving the motility, viability, and membrane integrity of chilled canine semen for up to 36 hours. The storage temperature did not seem to affect the semen quality, suggesting that canine semen can be refrigerated at 15ºC.

Semen extenders: An evaluative overview of preservative mechanisms of semen and semen extenders

“…Temperature is decreased to induce sperm inactivity during storage in liquid form. The globally accepted cooling temperature is between 4°C and 5°C to maintain semen quality and reduce gamete metabolism in dogs [16], stallions [17], bulls [18], goats [19], and rams [20], whereas in boars, the diluted liquid semen must be kept between 15°C and 17°C [21]. Mammalian sperm cells, especially for rams [22], boars [23], bulls [24], stallions [12], and men [25], are damaged by rapid temperature drop.…”