Cannabinoid transference and retention in tissues of beef steers fed hemp leaves

Hemp, <i>Cannabis sativa</i> L., is approved for production in the United States. Research has demonstrated that hemp leaves are viable as feed for ruminant livestock. However, cannabinoids restrict the integration of hemp leaves into livestock systems as these compounds accumulate in edible tissues of animals and are transferred to the humans consuming animal source products. The objective of this study was to analyze the presence of cannabinoids within rumen fluid, blood plasma, adipose tissue, and feces of beef steers consuming hemp. The trial included two 14-d periods followed by a 45-d monitoring period. In period 1, five ruminally cannulated steers were fed <i>ad libitum</i> hay. In period 2, steers continued to consume hay and were also supplemented hemp leaves at 3.9 mg/kg body weight (BW) cannabidiolic acid (CBDA) mixed with alfalfa cubes. Cannabinoid accumulation, including cannabidiol (CBD) and delta-9 tetrahydrocannabinol (Δ⁹-THC), was measured in tissues at various timepoints. Hemp consumption resulted in prolonged accumulation of cannabinoids in beef cattle tissues - at least 96 h in blood and 6 weeks in adipose tissue. Future research should determine a safe level of accumulation for and/or appropriate withdrawal time of cannabinoids in animals fed hemp before it may be utilized as a feed.