The peer-reviewed study, conducted on Holstein cows in Berlin and published Monday in the journal Nature Food, is one of the first major investigations into the use of industrial hemp as a potential supplement in animal feed.
For now, such use is illegal under US law, which does not allow THC in the food chain. But the new research comes as hemp, which has many industrial uses, continues to emerge from an agricultural exile that dates back to the “refrigeration madness” hysteria of the 1930s.
Hemp is the common name of the plant Cannabis-sativa. Humans have cultivated it for thousands of years. Its fibers are prized in making ropes, among many other uses. George Washington grew it at Mount Vernon in the late 1700s, and in recent years the estate has grown it again.
The flowers of the cannabis plant have high concentrations of delta-9-tetrahydrocannabinol — THC. It is the molecular compound that provides a high to someone who smokes or consumes it. Hemp with high levels of THC is called “marihuana” in the curious federal spelling, and remains a Schedule 1 substance under the Controlled Substances Act of 1970.
Industrial hemp is not the potted plant grown by people hoping to grow their own weed. Under the 2018 Farm Bill, industrial hemp is no longer listed as a controlled substance as long as it contains no more than 0.3% THC.
One of the byproducts of this change in the law is the booming market for another hemp-derived molecular compound, cannabidiol or CBD. It is generally marketed for its purported health benefits. You can get a shot of it in your coffee if you go to the right cafe.
The claimed health benefits of CBD for the most part lack the imprimatur of the Food and Drug Administration. The FDA has only approved a few hemp-derived products and sent warning letters to some companies making scientifically unclear claims about CBD products.
While all of this is ironed out by scientists and regulators, the hemp industry continues to grow. It’s still a tiny part of the agricultural products market, but that could change. Hemp could be a great source of animal feed if government regulators approve it, said Erica Stark, executive director of the National Hemp Association. Hemp seeds contain no THC, she said, and are high in protein.
“It’s going to be a very big market. There are actually feed shortages in this country right now, ramifications of what is happening in Ukraine, droughts and other crop failures,” Stark said.
Researchers from the German Federal Institute for Risk Assessment found no behavioral changes in the cows given the whole hemp plant, which contained very low levels of THC. According to the study, it was only when fed only the parts of the hemp plant with higher THC concentrations – including the flowers and leaves – that the behavioral effects appeared.
These effects included slower heart rate and breathing, “pronounced tongue play, increased yawning, salivation, formation of nasal secretions” and redness of part of the eyes, the report said. Some animals “displayed a cautious, sometimes unsteady gait, unusually long and abnormal stance.”
The animals also ate less and produced less milk, according to Robert Pieper, head of the institute’s food chain safety department and co-author of the new paper.
“It’s a big effect on animal health. Not a positive effect,” he said. But he didn’t predict how it would play out in the political world.
Industrial hemp has been gradually legalized in the United States through the 2014 and 2018 Farm Bills amid a general but patchwork relaxation of laws against marijuana use.
However, this legalization has regulatory limits. The FDA continues to consider THC, CBD and other cannabinoids as contaminants in the food supply.
“You’re not going to see CBD-enriched milk on the shelves for long,” said Jeffrey Steiner, director of the Global Hemp Innovation Center at Oregon State University.
Steiner, who was not part of the recently published research, experimented with hemp as a feed supplement for dairy cows, sheep and poultry. But his team has only had permission to study hemp since 2019, and he stressed that a lot more research needs to be done before the plant is likely to gain regulatory approval as a food. animals.
The plant was stigmatized and caught up in racist and chauvinistic ideology in the 1930s, when allegations of marijuana use were among rhetorical attacks on Mexican immigrants. Steiner said a 1937 federal marijuana tax essentially shut hemp out of the market. During World War II hemp was again used in the war effort, and Henry Ford even exhibited a car made partly from hemp, but the reprieve was brief and the Substances Act of 1970 controlled prohibited the cultivation of the plant.
“All this time hemp was stuck in the time capsule and there was nothing you could do with it,” Steiner said. “Now it’s about catching up, letting hemp enter the market, and letting science inform decision-making.”
The dairy industry will likely want to use hemp as a food additive if it gains federal approval and is competitive with other protein sources, said Jamie Jonker, science director for the National Federation of Dairy Producers. The industry, he said, has struggled with rising feed and energy costs, although some of that pressure has been eased by high milk prices.
Another possible use of hemp in livestock is as a stress reducer, such as when cows are transported, said Michael Kleinhenz, assistant professor of cattle production medicine at Kansas State University. He conducted research on hemp-fed steers and the animals tended to become calmer, he said.
“We don’t know if they have this buzz or something,” Kleinhenz said. But they have lower levels of stress hormones, he said. Cannabinoids reduce stress, he thinks, but “we still need to understand this mechanism in animals.”
Jonker said he’s heard of CBD-enriched dairy products, such as ice cream, being marketed in the Pacific Northwest in recent years. But any innovation in milk marketing must be cautious, he said.
“Milk has an incredible halo in the average person’s mind of being pure,” Jonker said. “There’s always a careful approach in innovation to make sure you don’t cause image problems with that halo.”