Effect of fractioned collection on sperm kinetics and viability of cooled and frozen stallion sêmen

Abstract

Several studies have been conducted and questioned about the real need of the seminal plasma on fertilization process. The existence of a significant variation in the refrigerated semen motility among stallions may in part be due to the different compositions of the seminal plasma. The seminal plasma is removed during the cryopreservation equine semen process due its negative effect on sperm viability. However most studies that relate to sperm survival during storage have been performed with whole ejaculate and there are few studies that assess the individual influences of the fluid produced by accessory sex glands on semen. The aim of this study is to evaluate and to compare the effects of fractionated semen collection on stallions classified as bad coolers and bad freezers and good coolers and good freezers on the survival, motility, plasma membrane integrity and mitochondrial activity of equine sperm before and after the cryopreservation process of cooling and freezing and to compare these data to conventional collection (whole ejaculate). Therefore is expected an improvement in the sperm quality on the sperm rich fraction when compared to the others, especially on the semen samples from stallions classified as bad coolers and bad freezers. (AU)