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The research on cannabinoids is constantly expanding, but generally, as humans, we think in anthropocentric terms when it comes to research. Primarily, we care about how cannabinoids affect us (and maybe our pets). But hemp has widespread uses, and its potential as a feed source is widely touted.

But what happens when cows are given industrial hemp as feed? Does it cause physiological changes, either positive or negative? And importantly (for people who eat cows), would cannabinoids build up in animal tissues to be passed on to humans? These are some of the questions that Kansas State researchers set out to answer in their recent research, according to the opening paragraphs of the study:

“If hemp is to be utilized as an ingredient in the ration of cattle, it is prudent to know and understand the pharmacokinetics and potential biological effects of cattle exposed to repeated doses of cannabinoids present in industrial hemp,”

For the study, sixteen male Holstein cattle were divided into two treatment groups. The first group was fed industrial hemp (infused with CBDA, the acidic precursor of CBD) mixed with grain for two weeks. The second group of cows was the control, which was fed only grain.

The first discovery was that, as it turns out, cows don’t dig the taste of hemp. According to  Michael Kleinhenz, assistant professor of beef production medicine at the K-State College of Veterinary Medicine, the cows “didn’t find the plant particularly palatable. We had to grind it down and mix it with something sweet like molasses to get cattle to consume it.”


That hurdle accomplished, researchers began to notice over the course of the study that there were significant behavioral differences between the two groups. They observed that the cows that ate hemp feed spent more time lying down and generally showed fewer signs of stress.

This kind of chilled out behavior seems to be explained by what researchers observed in the cows’ pharmacology regarding stress hormones, namely that cannabinoids decreased the stress hormone cortisol as well as the inflammatory biomarker prostaglandin E2.

According to the study authors, this is evidence that “hemp containing cannabidiolic acid, or CBDA, may decrease stress and inflammation in cattle.”

You might imagine when you drive by a field of cows chewing their cud, that the life of a cow would not be particularly stressful – but apparently, that would be wrong. In fact, cows experience a lot of stress throughout their life span. And whether that stress comes from weaning, transportation, or the close quarters of feedlots, stressed-out cows are not healthy cows.

That cows feeding on hemp are more relaxed was not an expected outcome of the study –  but could be good news to ranchers who would rather not deal with stress-induced illness in their cows. (Respiratory infections are common among stressed cattle.)

But further, the researchers gleaned vital information about whether cannabinoids like CBDA accumulate in cow tissue – obviously a huge issue if hemp is to be used as feed for cattle that will be consumed by humans:

“Our new research helps us better understand how cannabinoids present in industrial hemp interact with bovine physiology and pharmacology,” Kleinhenz said. “For instance, we now know that repeated daily doses of CBDA via feeding hemp does not result in accumulation of cannabinoids in the blood. Additionally, it …shows that each cannabinoid has its own absorption and elimination profile.”

Depending on what cannabinoids are present in a specific crop of hemp, researchers will need to verify those findings for other cannabinoids as well.

But one of the potential outcomes of the research is increasing the sustainability of hemp. For example, the ability to use the hemp biomass that is left behind after cannabinoids have been extracted would add stability to the hemp market for farmers, providing a market for what is currently considered waste.

Another study, currently taking place at Oregon State University, is looking specifically at post-extracted hemp biomass and that study will also be looking closely at what happens to leftover cannabinoids like THC. But according to a recent interview with OSU’s Massimo Bionaz, co-investigator on the research, there’s still a long way to go before industrial hemp is approved as feed for livestock:

“Considering the data we’ve gotten so far, yes, there is cannabinoid [left in the biomass]. Is that significant for the human? I don’t think so. However, it’s the FDA deciding it, not us.”