Sperm Transport in the Mare Reproductive Tract: A Review

The objective of this study was to review the literature on sperm transport in the mare. During this process the sperm cells must reach the oviducts in order to fertilize the oocyte, but before reaching this site it must go through the uterus that is a hostile environment at this moment since there is an inflammatory reaction in this location that aims to eliminate excess spermatozoa and bacterial contaminants. Sperm cells can be ob-served 30 minutes after artificial insemination and remain in the uterine tubes for at least 24 hours. It was found that the sperm cells can be observed in 62.6% of the mares after insemination when using light mi-croscopy, both in the uterine glands and the epithelium of the uterus. Uterine glands may act as a reservoir for sperm. After artificial insemination the number of mares with spermatozoa in the uterine epithelium, glands and utero-tubal junction decreases over time