Use of milk with different fat concentrations as extenders for equine cooled semen

Abstract Two trials were performed to verify the viability of extenders equine cooled semen. The objective of the first trial was to verify the efficacy of whole and semi-skimmed UHT milk compared to skim milk. Fresh semen samples were analyzed and later diluted in UHT whole milk, semi skimmed and skimmed milk. Sperm motility and vigor, CFDA / PI and HOST tests were performed post-dilution (0h), and in semen cooled at 5oC after 24 and 48h. There was no difference between the 3 extenders, for sperm motility (p = 0.9880), vigor (p = 0.7249), CFDA / PI (p = 0.3882) and HOST (p> 0.01). There was a decrease in semen quality over time (p <0.01), regardless of the extender used. It can be stated that in the absence of skimmed UHT milk, semi-skimmed and whole milk can be used since they do not impair the quality of refrigerated semen stored for up to 48 hours. In the second trial the objective was to verify the efficacy of the skim milk compared to commercial extenders (Botusemen® (BS) and Botusemen Special® (BSS)). Soon after semen collection, the samples were diluted with UHT skim milk (LD), Botusemen® (BS) and Botusemen Special® (BSS). Semen analysis followed the same protocol as the first experiment. BSS-cooled semen showed higher HOST and CFDA / PI (p <0.001) in 24h and 48h indicating that BSS diluent promotes increased sperm longevity compared to the others analyzed.