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Cows Given Hemp Feed To Produce Milk With THC

German researchers have found that industrial hemp-fed dairy cows produced detectable levels delta-9 THC. The compound that is most closely linked to the effects of marijuana has been discovered in a new study. The behavior changes in cows could be a result of cannabinoids being ingested by the feed.

“This is important, as we had no data to know to what extent cannabinoids entered the milk of dairy cows,” Michael Kleinhenz, an assistant professor in beef production medicine at Kansas State University College of Veterinary Medicine who was not involved in the research, told NewScientist.

The German Federal Institute for Risk Assessment provided 10 lactating milk cows with hemp feed that contained varying levels of cannabinoid content. The cows were studied over a period of weeks, with researchers collecting data on the animals’ behavior and conducting lab analysis on blood, milk, and fecal samples.

Research showed that feed type played an important role in the effects of the hemp feed on dairy cows. Fermented feed from whole hemp plants was less effective than traditional corn feed for dairy cows. 

The cows who were fed feed made with cannabinoid rich hemp flowers, leaves and seeds showed noticeable behavioral changes. The milk of the cows contained detectable amounts of cannabinoids, including delta-9 THC. According to the researchers’ calculations, these cows consumed up to 86 times the amount of THC that is required to get humans high.

The effects observed by the researchers included slower heart rate and breathing, “pronounced tongue play, increased yawning, salivation, nasal secretion formation,” and reddening of a portion of the eyes, the report states. Some animals “displayed careful, occasionally unsteady gait, unusually long standing and abnormal posture.”

Robert Pieper (head of the German Institute’s department of food safety and coauthor of the study) stated that cows fed hemp feed also had lower milk production and ate less.

“That is a strong effect on animal health,” Pieper said, according to a report from The Washington Post. “Not a positive effect.” 

Kleinhenz’s research has shown that steers who were given hemp from Kansas State University had a tendency to be calmer.

“We don’t know if they have that buzz or whatnot,” Kleinhenz said. Kleinhenz said the cattle had lower stress hormones. He believes that the cannabinoids in the feed reduce stress, but “we still have to figure out that mechanism in animals.”

With the passing of the 2018 Farm Bill, hemp was made legal in the United States. The Food and Drug Administration (FDA) has not yet allowed cannabinoids, including CBD, into U.S. food supplies. Federal regulators also have yet to approve animal feed made of hemp.

We need to do more research

Jeffrey Steiner, director of Oregon State University’s Global Hemp Innovation Center, has experimented with hemp as a feed supplement for dairy cows, sheep, and poultry. However, he said that research on hemp as a feed supplement for dairy cows and sheep began only in 2019. He added that more study is needed to approve hemp animal feeds by regulatory agencies.

“You’re not going to see CBD-enhanced milk on the shelf for a long time,” said Steiner, who did not have a role in the German study.

Serkan Ates is an Oregon State University Corvallis agronomist who has researched hemp consumption among chickens, sheep, and lambs. He says that because of the potential to pass on cannabinoids in milk, “it may not be possible to feed this to high-yielding dairy cows.”

“But there is plenty of low-hanging fruit to explore, like feeding hemp to non–food-producing animals like heifers or young lambs,” Ates said.

Erica Stark is the executive director at the National Hemp Association. She stated that hemp can be used to make high quality animal feed if the regulators allow it.

“It’s going to be such a really large market,” Stark said. “There’s actually animal feed shortages in this country right now, ramifications of what’s happening in Ukraine, droughts and other crop failures.”

The study, “Transfer of cannabinoids into the milk of dairy cows fed with industrial hemp could lead to Δ9-THC exposure that exceeds acute reference dose,” was published online on November 14 by the peer-reviewed journal Nature Food.