Member News
Free Registration Now Open for 2021 US Equestrian Annual Meeting | January 13-17, 2021
US Equestrian offices will be closed Monday, January 18th, 2021 in observance of Martin Luther King Jr. Day.
As a part of our efforts to protect the health of our employees, US Equestrian is working under a flexible work plan for our staff. As we transition to this modified format, there may be interruptions to service. We will do our best to have all services fully functioning as quickly as possible. Customer Care can be reached by emailing [email protected], online chat or leave a voicemail by calling (859) 258-2472. Thank you in advance for your understanding and patience.

On December 1, 2019, medroxyprogesterone acetate (MPA) became a prohibited substance under USEF Equine Drugs and Medications Rules.  Due to the length of time MPA may stay in a horses system, the enforcement for this substance will begin on June 1, 2020.  This delay in implementation will allow for horses to be withdrawn from the substance, as it can be detected for an extended period of time.  The USEF recommends that no horse be administered MPA following December 1, 2019 to ensure compliance with the June 1, 2020 enforcement date. 


For additional information, please contact the Equine Drugs and Medications Program at 800-633-2472 or by email:  medequestria[email protected]


Forms and Publications

Basic MPA explanation

Slides describing what MPA is.

Letter from Veterinarians RE: MPA

Letter received from 23 equine veterinarians to Mr. Murray Kessler, President of USEF and Dr. Stephen Schumacher, Chief Administrator of the Equine Drugs and Medications Program.

Addendum to Veterinary Letter; MPA related horse reactions

List of MPA reactions from veterinary group

American Association of Equine Practitioners Statement on the Use of Medroxyprogesterone Acetate in Competition Horses

American Association of Equine Practitioners Statement on the Use of Medroxyprogesterone Acetate in Competition Horses (2019)

Side Effects May Include: Sudden Death

Chronicle of the Horse Article 10.11.19

Sport Horse World Questioning Use of Compounded Drug After Reports of Sudden Death

Horse Racing News Paulick Report

Efficacy of Medroxyprogesterone Acetate in Suppression of Estrus in Cycling Mares

Peer reviewed research

Lay Summary for Depo-Provera(R) (medroxyprogesterone acetate); Does this Medication Block Estrus in Mares?

Lay Summary

The inability of some synthetic progestagens to maintain pregnancy in the mare

Peer reviewed research

Prevalence of Low Bone Mass and Osteoporosis in Long-Term Users of the Injectable Contraceptive Deport Medroxyprogesterone Acetate

Peer reviewed research