Some veterinarians and horse owners use MPA, a synthetic progestin, in an attempt to suppress or control estrus and related behaviors in mares. | Photo: Anne M. Eberhardt/The Horse

US Equestrian (USEF) has announced that, beginning June 15, all medroxyprogesterone acetate (MPA) disclosure forms must be submitted electronically.

Currently, USEF accepts both electronic and paper disclosure form submissions. More information on how to submit the electronic form is available on the USEF website.

Some veterinarians and horse owners use this synthetic progestin, also known as the human product Depo-Provera, in an attempt to suppress or control estrus and related behaviors in mares. Its use is currently is permitted at USEF-licensed national competitions; it is not permitted for use in Fédération Equestre Internationale (or FEI) competitions. Officials are working to better understand MPA use in horses competing at USEF competitions, and the disclosure forms will continue to allow them to gather pharmacokinetic data in relation to MPA administration, including how long it lasts in horses’ systems