Kansas researchers find that feeding hemp to cattle mellows the herd

By Suzanne Perez ksnewsservice.org

WICHITA, Kansas — A new study suggests that feeding cattle industrial hemp — a horticultural cousin of marijuana — reduces their stress levels and encourages them to lie down more.

This could prove beneficial for ranchers as relaxed steers tend to be healthier. Researchers from Kansas State University said hemp could be a natural way to reduce stress-related respiratory infections and other ailments when cattle are transported or weaned from their mothers.

Mike Kleinhenz, assistant professor of beef production medicine at K-State College of Veterinary Medicine, recently published the study’s findings in Scientific Reports.

“We may have a more natural way to reduce stress in cattle,” he said. “And for some of the benefits, we’re just scratching the surface.”

16 Holstein oxen took part in the Kleinhenz study. For two weeks, half of the oxen ate conventional feed and the other half a feed mixture containing hemp. It’s a cannabis strain that contains the chemical compound CBD with smaller amounts of the psychoactive component THC – the stuff that gets you high.

CBD is a popular remedy for relieving pain and anxiety.

Kleinhenz and his team tracked the cattle’s movements and also monitored their blood for cortisol and prostaglandins, which are biomarkers of stress. Compared to the control group, the hemp-eating oxen spent more time lying down and had fewer stress hormones.

The team also found that the hemp was absorbed but did not accumulate in the oxen’s systems, Kleinhenz said.

“It was kind of an exploratory study that produced some really interesting results,” he said. “You don’t usually go fishing and find stuff like that.”

Cattle that are more relaxed could benefit ranchers when it comes time to wean them or take them to foraging areas when the stress of being in close quarters sometimes leads to respiratory infections or other ailments.

After the 2018 Farm Bill legalized hemp production in the United States, interest in hemp as an agricultural commodity, including animal feed, grew. But before hemp could be fed to livestock or pets, approval from the US Food and Drug Administration would be required.

In 2020, the K-State team received a $200,000 research grant from the US Department of Agriculture to analyze the safety of industrial hemp as animal feed.

Currently, growers trading in the CBD oil market hire processors to extract the oil from hemp seeds or flowers. The process leaves behind large amounts of plant material of little value.

If these byproducts, which contain trace amounts of CBD or THC, could be used to feed livestock, it would benefit ranchers and keep waste out of landfills, Kleinhenz said.

“Basically, it’s the old cow recycling system,” he said. “Similar to the ethanol story where cattle are fed grain from ethanol production.”

Follow-up studies will look at how cattle absorb CBD compounds and what effects they may have on food.

“We want to understand the entire time frame from when an animal last consumes (hemp compounds) to when it can safely enter the food chain and not have those compounds in the system,” Kleinhenz said.

Suzanne Perez reports on education for SMEs in Wichita and the Kansas News Service. You can follow her on Twitter @SuzPerezICT.