From The Chronicle of the Horse

It was just another afternoon at the barn for assistant trainer Sara Greene.* The head trainer was out of town, and Greene was following her normal routine, which included administering medroxyprogesterone acetate, the compounded form of Depo-Provera, to several horses. She injected the last horse on her list and then left his stall to put away the bottle. READ MORE...

From US Equestrian

As a result of a number of recently reported equine fatalities associated with the use of Medroxyprogesterone (MPA), US Equestrian will reconvene its MPA Panel to further analyze the use of this substance in horses competing at USEF-licensed competitions. 

This latest information on equine fatalities associated with the use of MPA underscores the need for the MPA Panel to meet and review the critical information about this substance in order to provide our members with the information they need to protect their equine partners.  READ MORE...

Medroxyprogesterone acetate (MPA) is a synthetic progestin hormone administered to mares off-label in an attempt to suppress behavioral estrus. However, a controlled research study found that MPA was not effective at suppression of behavioral estrus.¹ Many veterinarians believe MPA modifies behavior by producing a calming effect in the horse and does not have a therapeutic benefit that goes beyond this behavior modification. Therefore, the AAEP recommends that MPA should not be administered to horses in competition.

¹ Gee EK, C DeLuca, JL Stylski, PM McCue. Efficacy of medroxyprogesterone acetate in suppression of estrus in cycling mares. J Equine Vet Sci 2009;29:140-145.