Cows getting stoned on hemp have shown that certain feeds for livestock contain enough cannabinoids to have a profound effect on dairy cows. Their red eyes and unsteady gaits, not unlike those of stoned humans, are raising questions about whether or not the cows may puff-puff-pass the psychoactive effects on to human consumers drinking their milk.

Hemp is a cost-effective crop because it’s cheap to buy, quick to grow, and is nutritious for farm animals. However, as a relative of the Cannabis sativa plant, hemp also contains tetrahydrocannabinol (THC), which is the thing that gets you high when you smoke or ingest cannabis.

While the concentrations of THC are far less compared to that of C. sativa, hemp instead boasts a large volume of cannabidiol (CBD). You’ve likely heard a lot about the potential benefits of CBD in the media, which include the management of treatment-resistant anxiety, addiction, and possibly even the treatment of some tumors.

To see how hemp impacted the behavior of dairy cows, researchers at the German Federal Institute for Risk Assessment fed crops containing varying CBD concentrations to 10 lactating Holstein Friesian cows. They were given the feed across several weeks, during which time samples of their milk and feces were collected.

The results showed that the extent to which a cow’s behavior was affected depended on what parts of the hemp plant were used, and how they were treated, as these variations influenced the CBD and THC concentrations. Lower concentrations in fermented whole plant hemp feed didn’t affect the cows all that much, but cows on the higher concentration feed made from leaves, flowers and seeds had a very different experience.

As it happens, cows fed high levels of CBD and THC react fairly similarly to humans under the influence. These cows had red eyes, unsteady gaits, yawned more often and also started waving their tongues all over the place. The cow’s behavior normalized after they were no longer on the hemp feed, but that they were so affected raises ethical questions about the impact of this feed on captive animals.

A lasting effect of a diet rich in CBD and THC also has implications for the way some humans consume dairy products, as both compounds were found to linger in the milk for weeks after hemp feed was stopped. Furthermore, the cows’ food intake and milk output fell while under the influence.

As for whether the resulting milk could make you high after a bowl of Special K, it’s possible but not certain. Analyses of milk samples appeared to indicate that levels of THC could exceed the acute reference dose for humans were it rolled out to consumers. 

Hemp has many benefits in terms of cost and nutrition, and the downsides only apply to feed combinations in which the high cannabinoid concentrations are being fed to food-producing animals. However, while it’s not certain if this would get you high, and there was insufficient data to draw firm conclusions on CBD concentrations, it raises questions about the capacity of a hemp diet to trickle through the dairy chain.

The study was published in Nature Food.

[H/T: Science]