Frozen semen management in equine breeding programs.

Success with frozen semen requires attention to detail and a basic understanding of the techniques for properly handling and thawing and inseminating frozen semen. Practitioners should also be familiar with strategies used for managing mares for insemination with thawed semen. This manuscript will review those techniques and also present fertility data collected in a commercial setting. Factors that affect pregnancy rates for mares inseminated with frozen-thawed semen such as timing and frequency of insemination were examined for two separate data sets consisting of 332 and 536 mare cycles collected during the 2002 and 2003 breeding seasons. There were no differences observed in pregnancy rates for mares inseminated once or multiple times in a given cycle (51.5% versus 51.7% for data set 1 and 47.1% versus 46.1% for data set 2). Mares inseminated twice on a cycle, once before and once after ovulation, became pregnant at a rate similar to mares inseminated once within 6h post-ovulation (48.1% versus 47.3%).