Pharmacokinetics of single feeding of cannabidiol in cattle: A pilot study

Haley Cornette


Cannabidiol (CBD) is a substance that has been used in complementary medicine for many years. However, modern medicine has little knowledge of how this substance is utilized and metabolized in ruminant animals. Regulations on quality assurance and use in animals are lacking, and CBD supplementation in livestock is not approved. If CBD supplements can be shown to be safe and effective, detection in the animal will be important for determining regulation of use. A withdrawal period can then be established to allow time for deterioration of product to safe levels before livestock products enter human markets. This study sought to determine the pharmacokinetics of an oral CBD supplement in cattle. An oral gel cannabinoid-containing product, formulated for equine, designed to be absorbed through mucosal membranes was used in this study. Based upon current knowledge, appearance of cannabinoids in plasma should occur at one-hour post administration and increase to peak concentrations at approximately ten hours. Blood collections from the jugular vein of two mature cows occurred at 0 (post-treatment), 0.5, 1, 2, 4, 8, 12, 16, and 24 hours. Subjects were housed in outdoor working pens for the duration of the study, with free access to water and hay. Multiple cannabinoids were detected, which aligned with the guaranteed analysis stated by the manufacturer. Though the product was labeled as containing no tetrahydrocannabinol (THC), laboratory analysis also detected THC within the sample. Detection of cannabinoids was inconsistent between subjects. Cannabinoids were first detected in plasma at 1-hour post treatment in one subject, and at 12 hours post treatment in the other. Only CBD and 7-hydroxy cannabidiol (CBD-7 acid) were detected during the collection period. Plasma cannabinoid concentrations were still rising at the end of the collection period, indicating that peak concentrations had yet to be reached. Appearance of cannabinoids in plasma indicated that oral gel cannabinoid product was able to be metabolized and absorbed by the ruminant animal. A half-life of the product was unable to be determined. Future studies should consider expanding sampling numbers and extending collection period.