Comparison of extenders and storage temperature in chilling canine semen

The objective of this study was to evaluate the influence of a commercial milk-based extender compared with a self-made egg yolk extender in the quality of canine semen, stored with two different temperatures (5°C or 15°C) for short-term cooling. The ejaculate obtained was divided into two aliquots of equal volume, that was diluted with Milk extender or Egg Yolk extender, presenting a final concentration of 100 x 106 spermatozoa/mL. Diluted semen was placed into transport containers, maintaining final storage temperatures of 5°C and 15°C. Quality of chilled semen was assessed after 12, 24 and 36h of storage. Semen diluted with Milk extender resulted in higher motility, vigor and plasma membrane integrity (P<0.05) of spermatozoa than Egg Yolk extender. Inside each group, no influence of stored temperature was found concerning semen quality. The difference observed between extenders, could be due to the standard formulation of the commercial Milk extender, besides the presence of glucose in its composition. In conclusion, Milk extender presented a superior preservation of motility, viability and membrane integrity of chilled canine semen up to 36 hours of storage than Egg Yolk extender, and the temperature of storage did not interfere in semen quality, suggesting that 15 °C could also be used for canine semen refrigeration.