Superovulation, embryo recovery, and pregnancy in seasonally anovulatory mares treated with recombinant equine FSH

PABLO J. ROSS, MARIA V. ETCHARREN, MARCELO H. MIRAGAYA, ADRIAN MUTTO, MARK COLGIN, JANET F. ROSER1, LUIS LOSINNO2

Vancouver

Congreso; ICAR 2012; 2012

ICAR

We evaluated the effectiveness of different treatments with recombinant equine FSH (reFSH) to stimulate follicular growth, multiple ovulations and embryo production in seasonally anovulatory mares. During winter (July-August in Argentina, South America) forty light breed donor mares, selected based on their reproductive records to have no more than 20% multiple ovulations per season, and presenting follicles 35 mm). Ovulations were detected in 80% of mares in Groups 1 and 2, 50% of mares in Group 3 and in none of Group 4 (Control). Among ovulating mares, no differences in number of ovulations, number of embryos recovered, or pregnancy rates were observed among reFSH treatments. Overall, a 59% pregnancy rate was achieved with embryos collected and transferred during the anestrus season. These results indicate that treatment with reFSH during deep anestrus results in follicular development, ovulation of fertile oocytes, and production of embryos that established viable pregnancies after transfer. Also, a single daily administration of reFSH was as effective as two daily administrations, which allows for a simplified administration regimen. In conclusion, reFSH treatment of seasonally anovulatory mares allows production of viable embryos during the winter season