USDA Cattle Study Finds Minimal Cannabinoid Residues After Hempseed-Cake Feeding
A 2023 USDA and North Dakota State University study found that cattle fed a low-cannabinoid hempseed cake retained measurable THC and CBD primarily in body fat, while levels in muscle, liver and kidney remained below detection limits.
The research, published in Food Additives & Contaminants, examined 32 crossbred heifers. Sixteen animals received a ration containing hempseed cake at 20% of dry matter for 111 days, while the remaining cattle received a control diet. The researchers then tested urine, plasma and edible tissues after withdrawal periods of zero, one, four and eight days.
Hempseed cake is the protein- and fiber-rich byproduct left after oil is extracted from industrial hemp seeds. It is not the same as CBD-rich hemp biomass or a product formulated to deliver cannabinoids. In the study, the cake contained an average of 1.3 milligrams per kilogram of combined CBD and THC.
Researchers detected combined CBD and THC in adipose tissue at concentrations of roughly 6.3 to 10.1 nanograms per gram, including in cattle harvested without a withdrawal period. The compounds were not detected in skeletal muscle, liver or kidney. Some cannabinoid acids were found sporadically in blood and urine, and trace residues remained in the kidney of some animals at the eight-day withdrawal point.
Using a conservative dietary exposure threshold, the scientists estimated that the likelihood of a person consuming enough beef fat from the hempseed-cake-fed cattle to reach an acute reference dose for THC was remote. The findings suggest that meat from cattle fed this particular low-cannabinoid ingredient would contribute very little dietary THC exposure under the study conditions.
The results do not amount to a blanket determination that all hemp-derived feed ingredients are safe, nor do they establish that hempseed cake is approved for use in cattle feed. The study involved a specific formulation, feeding level and cattle population, and it measured residue transfer rather than long-term effects in humans.
The research also supports earlier work indicating that hempseed cake can provide adequate nutrition for finishing cattle, although its energy value and performance may differ from conventional feeds such as dried distillers grains. A companion cattle-nutrition study found that animals could maintain acceptable performance when hempseed cake was included in a balanced finishing diet.
Under current FDA guidance, hemp-derived substances still must meet the legal requirements that apply to animal-food ingredients. The agency says there are currently no approved food-additive petitions, AAFCO ingredient definitions or recognized GRAS conclusions covering hemp-derived substances for animal food. That regulatory status remains separate from the USDA study’s scientific finding that cannabinoid residues were very low in the tested cattle.
