Cannibidiol (CBD) supplementation in horses: A pilot study

Cannibidiol (CBD) is sold for various uses in humans and animals. Thus far, CBD has not demonstrated effects similar to delta-9 tetrahydrocannabinol (THC), the psychoactive component of marijuana. While some animal species have demonstrated responses to CBD supplementation, published literature on equines is absent. The lack of FDA approval and studies to support claimed benefits make regulating product quality and recommending dosages difficult. The objectives of this project were to: 1) determine dosages that allowed for CBD detection in equine blood; and 2) evaluate time required for the appearance of maximum concentration and half-life of CBD in equine blood. Two mature Quarter Horse geldings were used to address objective 1. Two products currently available for sale were evaluated, a pellet (PEL, 25 mg/serving) and an oil (OIL, 25 mg/ml), with one horse receiving each treatment. Manufacturer recommended doses were 25-50 mg/d. Each horse was provided one 50 mg dose. At 1 and 2 hr post administration, blood samples were collected via jugular venipuncture. Samples were centrifuged before serum was collected and analyzed. There was no CBD reported in any sample. Unpublished data in horses and published data in canines have reported the presence of CBD after supplementation. It is possible that the time of appearance of CBD in equine serum is outside the sampled time frame. It is also possible that the concentration of CBD used was not sufficient to result in a positive test. Finally, improper handling of the samples may have resulted in degradation of CBD before analysis. Continuing studies are being conducted to address the objectives, and studies are scheduled to end December 2019. Results from these pilot projects can be used to design future studies of CBD supplementation in horses and other animals