Shorten cycling with prostaglandins

Many hormonal techniques can bring in various desired results. They allow spreading or grouping of mares for breeding, and shortens the waiting period due to missed ovulations. Prostaglandin administered to an diestrus mare lyses the CL causing return to estrus. Inject IM 5-10 mg dinoprost tromethamine (Lutalyse).The CL resists prostaglandin in the first 4-5 days post ovulation, but becomes responsive afterwards. Response depends on degree of follicular development at the time of injection.

In the absence of a dominant follicle, prostaglandin leads to estrus in about 2-4 days and ovulation in 6-12 days. Palpation of mares before prostaglandin injection, and teasing is necessary to cope with variable responses.