MRC issues advisories for horsemen

The Maryland Racing Commission has re-issued advisories on use of thyroid supplements and substances containing CBD, and also a reminder regarding horses on the vet’s list.

Thyroid supplementation is prohibited, and trainers may not have thyroid supplements in their premises on the racetrack or training centers, nor may they administer such supplements, unless the following conditions are met:

  • The horse has been diagnosed with hypothyroidism pursuant to a thyroid releasing hormone stimulation test (TRH). A T3 or T4 test without stimulation of the thyroid is insufficient to diagnose hypothyroidism.
  • The results of the TRH stimulation test must be submitted to Dr. Libby Daniel, the MRC Equine Medical Director.
  • If approved by the Equine Medical Director, the horse may be treated with only Federal Drug Administration-approved medications for hypothyroidism prescribed by a veterinarian. Possession of any thyroid supplements that are not pursuant to a veterinary prescription under this directive is prohibited and will result in strict disciplinary action.
  • If a horse is currently being administered a thyroid supplement, administration of the supplement should be discontinued and a TRH test conducted after a 30-day washout period.

Cannabidiol (CBD), a constituent of cannabis, is not permitted for use in horses. It is available in many over-the-counter nutritional supplements and in one FDA-approved prescription drug use to control childhood epilepsy.

The Racing Medication and Testing Consortium in an advisory noted there is risk of contamination in CBD products given the lack of regulatory oversight for extraction of CBD from the cannabis plant. There is no withdrawal guidance for the substance, which can and has produced positive test findings from racehorse samples.

CBD is categorized by the Association of Racing Commissioners International as a Class 2 substance in the Penalty B category. However, should a CBD product contain more than 0.3% tetrahydrocannabinol—commonly known as THC—it is a Class 1 substance in the Penalty A category on the ARCI list.

Regarding the vet’s list, horsemen are reminded that when they obtain a racehorse from another party, it is their responsibility to check with the Racing Office and/or regulatory veterinarians to ensure the horse is not on the vet’s list or any other list that would make the horse ineligible to run.

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