The United States Equestrian Federation (USEF) issued a statement regarding the use of equine nutritional supplements on April 1:

The United States Equestrian Federation does not certify, endorse, nor approve specific equine nutritional supplements as safe for use during recognized competitions.

As a service to USEF Members, and upon request, the USEF Drug and Medication Program office will review product labels to determine if forbidden substances are amongst the specific ingredients listed. However, all competitors are advised that the manufacture of equine nutritional supplements is not currently subject to formal regulation by any government agency; therefore the proportions, source, and quality of their ingredients may not be consistently controlled during the production process and may be highly variable from manufacturer to manufacturer.

In the unfortunate event that a forbidden substance is present in a sample collected by the USEF Drug and Medications testing program, the owner and trainer will be subject to the provisions outlined in GR 404 and GR 406 and will be held accountable as defined in Chapter 4 of the USEF Rule Book