Date on Honors Thesis



Animal Tech/Animal/Equine

Examining Committee Member

Shea Porr, PhD, Advisor

Examining Committee Member

Megan Taylor, PhD, Committee Member

Examining Committee Member

Lauren Willett, Committee Member


Research about supplemental feeding of cannabidiol (CBD) to horses is still in its early stages, but many horse owners are feeding CBD supplements for supposed benefits, including behavior and pain management. Cannabinoids work through the endocannabinoid system to modulate nervous and hormonal actions in the body, working to maintain a healthy homeostatic balance. Safety and efficacy have been tested for dosages of up to 500 mg of CBD per day for horses, but further research about the pharmacokinetics based on dosage amount and form of CBD are still needed. The objectives of this study were to evaluate the pharmacokinetics of single dose versus long-term feeding of a pelleted CBD supplement. In Project 1, eighteen Quarter Horse geldings were given a single dose of 50 mg (n=6), 100 mg (n=6), or 250 mg (n=6) of pelleted CBD. Blood samples were collected before treatment (0 hrs), and at 0.5, 1, 2, 4 and 12 hrs post treatment. The highest concentration of CBD in the blood was seen in the 250 mg group at 4 hrs post-treatment. The highest concentration of the metabolite 7-COOH CBD was again seen in the 250 mg group at 4 hrs post-treatment. However, both CBD and 7-COOH CBD concentrations appeared to still be rising at 12 hrs in the 50 mg group while they were decreasing in the other two groups. Project 2 utilized 24 horses (12 CON and 12 TRT), where TRT horses were fed 100 mg of CBD once a day for 8 weeks (wks). Blood samples were collected pre-treatment (0), and at 2, 4, 6 and 8 wks. The highest CBD concentrations were seen at 2 wks, but concentrations decreased at 4 wks before increasing again at 6 wks and remaining elevated at 8 wks. Results from these projects agree with some publications but differ from others, though no negative side effects were noted in any horse. More research is needed to better understand CBD metabolism and its effect in horses.