SUPEROVULATION: The Future is Now Patrick M. McCue DVM ...

ovulates, while the remainder of thefollicles regress and are permanently lost.Administration of eFSH twice beginning 5or 6 days after ovulation, followed byprostaglandins one day later to eliminate thecorpus luteum, will result in continueddevelopment of multiple follicles infollicular wave. Administration of hCG isrequired to induce a synchronized ovulationof most or all of the large follicles.Embryo collection should be performed 7 or8 days after ovulation of the first detectedovulation. Previous research studies havenoted that embryo collection successincreases as the number of ovulationsincrease in mares. This is especially true foryoung reproductively healthy horses. Oldermares may have a decreased response tosuperovulatory hormones and embryocollection success may be further limited ifthe uterine environment is compromised. Ingeneral, however, superovulation shouldincrease the efficiency of embryo transfer inmares.Clinical uses for eFSH in addition tosuperovulation include advancing the firstovulation of the year in transitional maresand enhancing pregnancy rates in maresbred to subfertile stallions. Researchperformed in the spring of 2003demonstrated that administration of eFSH tomares in the spring transition period resultedin ovulation after approximately 6 to 8 daysof treatment. Consequently, eFSH may bean effective management technique to getmares bred early in the season that are slowto respond to an artificial photoperiod orhave not maintained under lights at all.Additional research in the use of eFSH toimprove pregnancy rates is ongoing.Multiple embryos collected from asuperovulated mareEquine follicle stimulating hormone(eFSH) preparation2