Artificial insemination with frozen equine semen

inflammatory reaction, sperm transport and insemination technique

Abstract

This manuscript presents a brief historical review of investigations related to equine artificial insemination with frozen semen. The sperm-uterine interaction can be modified by the type of the insemination: concentration, total sperm numbers, motility/viability of sperm, volume, frequency and timing of AI. The frozen semen AI is widely used in the equine industry. The minimum recommended dose of spermatozoa has been established in 250 x 10⁶ progressive motile sperm for uterine body insemination. However, the minimum dose required for maintaining the highest fertility for each stallion may differ greatly and therefore is determined by individual variation of intrinsic stallion fertility as well as with the insemination site. Deep intra-uterine insemination is commonly accepted as a routine procedure for AI with low doses. The number of AIs per cycles does not seem to be a factor affecting the final outcome of pregnancy as long as the last AI is performed within 12 h before and 12 h after the ovulation. Contrary to the common belief, the mare’s oocyte remains viable and fully capable of fertilization for 12-15 h, and the embryo loss rate after post-ovulatory insemination does not begin to increase until 12 h post-ovulation. Therefore, in a postovulatory insemination regime, examination of mares at intervals of any less than 12 h does not improve pregnancy or embryo loss rates.