The Latest News on the Use of Cannabis in Horses

Both USEF and FEI list natural cannabinoids, synthetic cannabinoids, and other cannabimimetics as prohibited substances. USEF Equine Drugs and Medications Rules prohibit CBDs and their metabolites in show horses, which are likely to effect the performance of a horse due to its reported anxiolytic effects. This substance is no different than legitimate therapeutics that effect mentation and behaviour in horses.

Horses competing under USEF rules who test positive for CBD will be considered in violation beginning Sept. 1, 2019. As published literature does not exist noting detection times of these substances in the horse, and because products can widely vary in their compositions and concentrations, detections prior to Sept. 1 will receive warnings and will be considered to be in prior violation if there are additional CBD detections following that date.

Regarding CBD legalization for use in Canada, Jean Szkotnicki, president of the Canadian Animal Health Institute, explained, “Health Canada’s Veterinary Drugs Directorate is responsible for the review of data in support of a Drug Identification Number (DIN) being issued for a product,” she explained. “A DIN gives a company the right to market a product. Then the Regional Operation and Enforcement Branch has to ensure the product meets quality standards once in the marketplace.”

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But before a company can apply for a DIN for their product, they must first provide proof of efficacy. “The technical requirements that need to be met depend a lot on the nature of the health claims being sought for a veterinary drug,” said Szkotnicki. “Trials addressing human and animal safety would have to be conducted as well as clinical efficacy and quality trials.”

Dr. Wendy Pearson, a professor of equine physiology in the department of animal biosciences at the University of Guelph who has been involved in many efficacy trials for equine products, says she’s looking forward to researching the use of CBD for horses. “We don’t really have a scientific basis from which to make recommendations for horses. To my knowledge, there are exactly zero studies evaluating any kind of effect of CBD on horses.”

Dr. Pearson said the types of studies that would be required before equine health care professionals have any kind of basis for recommendations should include, as a minimum, “safety titration of dose.” This study (or series of studies) would seek to determine the safe range for a horse and once established, an effective dose would need to be determined. This will likely vary depending on the outcome measures researchers are looking for (i.e. lameness vs skin health vs cancer etc.).

“This is a huge task that would require significant investment to tackle,” said Dr. Pearson. “My feeling is that if we can get CBD for horses manufacturers to step up and contribute to the cost of some of these studies, we will be able to accelerate the timeline for legalization. But as long as there is no investment from the industry, it’s unlikely that we will get a lot of legalization support from the government.”

At this stage, it is very much a ‘buyer beware’ situation and horse owners should exercise caution when using any untested drug or supplement.