Abstract
The industrial hemp sector is growing and, in recent years, has launched many novel hemp-derived products, including animal feed. It is, however, unclear to what extent individual cannabinoids from industrial hemp transfer from the feed into products of animal origin and whether they pose a risk for the consumer. Here we present the results of a feeding experiment with industrial hemp silage in dairy cows.
Hemp feeding included changes in feed intake, milk yield, respiratory and heart rates, and behaviour. We combined liquid chromatography–tandem mass spectrometry-based analyses and toxicokinetic computer modelling to estimate the transfer of several cannabinoids (Δ9-tetrahydrocannabinol (Δ9-THC), Δ8-THC, Δ9-tetrahydrocannabinolic acid, Δ9-tetrahydrocannabivarin, 11-OH-Δ9-THC, 11-nor-9-carboxy-Δ9-THC, cannabidiol, cannabinol and cannabidivarin) from animal feed to milk. For Δ9-THC, which has a feed-to-milk transfer rate of 0.20% ± 0.03%, the acute reference dose for humans was exceeded in several consumer groups in exposure scenarios for milk and dairy product consumption when using industrial hemp to feed dairy cows.
From Conclusion: Our study shows that feeding cannabinoid-rich industrial hemp silage made from leaves, flowers and seeds leads to a decrease in feed intake and milk yield in dairy cows. Heart rate, respiratory rate and animal behaviour were also negatively affected… due to the high feed intake, cow’s milk reached substantial levels of Δ9-THC such that the exposure might exceed ARfD in some population groups in our exposure scenario based on the transfer properties presented here. For other cannabinoids, in particular for CBD, which was present in high amounts in industrial hemp (and thus also in cow’s milk after feeding), the data are currently insufficient, thereby preventing an assessment of possible health risks.
