Superovulation, embryo recovery, and pregnancy rates from seasonally anovulatory donor mares treated with recombinant equine FSH (reFSH)

ETCHARREN, MARIA V.; COLGIN, MARK; MIRAGAYA, MARCELO H.; LOSINNO, LUIS; ROSER, JANET F.; MUTTO, ADRIAN; ROSS, PABLO J.

THERIOGENOLOGY

ELSEVIER SCIENCE INC

Año: 2020 vol. 142 p. 291 - 295

0093-691X

The effectiveness of different treatments with recombinant equine FSH to stimulatefollicular growth, multiple ovulations and embryo production in seasonally anovulatorymares was evaluated. During mid-winter season (July-August in Argentina, SouthAmerica) forty light breed donor mares, presenting follicles 35 mm).Ovulations were detected in 80% of mares in Groups 1 and 2, 50% of mares in Group 3and in none of Group 4 (Control). Among ovulating mares, no differences in number ofovulations, number of embryos recovered, or pregnancy rates were observed among reFSH treatments. Of treated mares, 6, 7, and 5 produced embryos in Groups 1, 2, and3, respectively. The average embryo recovery rate per ovulated mare was 88%. Theaverage embryo recovery rate per ovulation was 43%. Overall, a 59% pregnancy ratewas achieved. These results indicate that treatment with reFSH during deep anestrusresults in follicular development, ovulation of fertile oocytes, and production of embryosthat established viable pregnancies after transfer. Also, a single daily administration ofreFSH was as effective as two daily administrations, which allows for a simplifiedadministration regimen.