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Researchers analyze safety of industrial hemp as cattle feed

A pair of studies at Kansas State University is bringing new insight to farmers and producers seeking to incorporate industrial hemp in cattle feed.

After the 2018 Farm Bill legalized hemp production in the U.S., interest has grown in industrial hemp as an agricultural commodity, including as feed for animals. FDA approval, however, through the Association of American Feed Control Officials would be required before hemp could be fed to livestock or pets.

“Although hemp can be legally cultivated under license in Kansas, feeding hemp products to livestock remains prohibited because the potential for cannabinoid drug residues to accumulate in meat and milk has not been studied,” said Hans Coetzee, professor and head of the anatomy and physiology department in the College of Veterinary Medicine.

A team of K-State researchers recently received a $200,000 Agriculture and Food Research Initiative Competitive Grant from the U.S. Department of Agriculture’s National Institute of Food and Agriculture to establish concentrations of cannabinoids in livestock after exposure to industrial hemp.

“Industrial hemp is typically grown to produce oil, seed, fiber and medicines,” said Michael Kleinhenz, assistant professor of beef production medicine. “While varieties of hemp may be planted for a single or dual purpose, such as for seed and fiber, byproducts consisting of leaves, fodder and residual plant fibers remain after harvest. These byproducts could serve as potential feedstuffs for animals. Because these are predominantly cellulose-containing plant materials, the ideal species for utilizing these feeds are ruminant animals, specifically cattle.”

While there is interest in the use of hemp for cattle feeds, there are questions about whether the feed can be used safely because of concerns about tetrahydrocannabinol, or THC, intoxication and the presence of other bioactive cannabinoids. Kleinhenz noticed that most research was focused on humans, mice and swine, but not on cattle.

“This is surprising because cattle can readily utilize industrial hemp byproducts as they can digest cellulose plant materials in their rumens,” Kleinhenz said.

Kleinhenz is part of a multidisciplinary research team consisting of pharmacologists, toxicologists, analytical chemists and horticulture experts. The hemp used in the studies was grown at K-State’s John C. Pair Horticultural Center near Wichita. Other K-State researchers involved include Geraldine Magnin, Zhoumeng Lin, Steve Ensley, Jason Griffin, Katie E. Kleinhenz, Shawnee Montgomery, Andrew Curtis, Miriam Martin and Coetzee. The research team also included John Goeser and Eva Lynch, Rock River Laboratories.

“We observed that the acidic cannabinoids, such as CBDA and THCA, are more readily absorbed from the rumen than other nonacid cannabinoid forms, such as CBD and CBG,” Kleinhenz said. “Now that we have found that some cannabinoids are readily absorbed from the rumen, the next steps are to study the tissue and milk residue depletion profiles of these compounds after animal feeding experiments. The effects of cannabinoids on cattle are also unknown.”

Follow-up experiments will include pilot studies to examine the effect of feeding hemp on animal behavior and immune function.

“Our goal is to fill in the knowledge gaps,” Kleinhenz said. “Until feedstuffs containing hemp are established as safe in animals, our data will assist producers in managing situations involving intentional or unintentional hemp exposures.”

The two published studies are “Nutrient concentrations, digestibility, and cannabinoid concentrations of industrial hemp plant components,” which can be found in the journal Applied Animal Science, and “Plasma concentrations of eleven cannabinoids in cattle following oral administration of industrial hemp (Cannabis sativa),” which was published in Scientific Reports.

Michael D. Kleinhenz et al. Plasma concentrations of eleven cannabinoids in cattle following oral administration of industrial hemp (Cannabis sativa), Scientific Reports (2020). DOI: 10.1038/s41598-020-69768-4

Researchers analyze safety of industrial hemp as cattle feed A pair of studies at Kansas State University is bringing new insight to farmers and producers seeking to incorporate industrial hemp

Should Farm Animals Be Eating Hemp?

An industry holds its breath as it works with regulators to approve hemp in animal feed.

Published on Dec 16, 2019 6:55AM EST Hemp

Sophie’s work has appeared in the Wall Street Journal, Atlas Obscura, City Limits, Edible publications, and more.

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Ever since the 2018 Farm Bill legalized hemp in the United States, there has been rising interest in hemp-derived products, including those that can be consumed. Regulators at the US Food and Drug Administration are racing to roll out regulations for these products that human consumers increasingly demand. But hemp in feed for cows and chickens on the farm? That’s a different story.

Because humans sometimes eat the food that comes from livestock, hemp-based animal feed will require a greenlight from federal regulators. Still, there is significant interest from those in the hemp industry who argue that hemp as an addition to animal feed is a no brainer: It’s easy to grow, an effective cover crop, and high in nutrients.

“Why wouldn’t I use that?”

Ethan Vorhes, an Iowa cattle farmer and director of the Iowa Hemp Association, said that when he first learned about the plant’s many uses, “I fell like a fish—hook, line, and sinker.” His family had grown hemp during World War II, he said, adding, “I got stuck on the notion that it gives me everything I need to accomplish making the meat healthier, and it helps with the soil in the crop rotation.”

He thought it would make sense to feed hemp to his own cattle. But it soon became clear to Vorhes that, despite hemp legalization, hemp products not yet approved for this use.

The FDA has raised questions about whether it’s safe for humans to eat meat, eggs, and dairy from production animals that ate hemp. In a speech about hemp and CBD at the National Industrial Hemp Council’s 2019 Hemp Business Summit in August of this year, Lowell Schiller, the Principal Associate Commissioner for Policy of the FDA, said, “When it comes to food-producing animals, we also need to think about how the ingredient might be passed through to meat, dairy, or eggs that humans might consume.”

In other words: Could cannabinoids show up in the food we eat from animals eating hemp? If so, what are the implications for regulating these animal products?

Though few US studies have assessed the risks of cannabinoid transfer in hemp to livestock, one conducted by the European Food Safety Authority in 2011 determined that hemp seed-fed cow’s milk to be safe, but warned of allowing whole hemp-fed cow’s milk on the market. THC levels in milk from cows fed whole hemp plants was considerably above the Provisional Maximum Tolerable Daily Intake (PMTDI). But when the cows were fed hemp-seed material in the same study, the THC transfer was well below the PTDMI. Its recommendation was “to put whole hemp plant-derived feed materials [on a] list of materials whose placing on the market or use for animal nutritional purposes is restricted or prohibited,” but to allow for a maximum THC level in “hemp-seed derived feed materials.”

Vorhes described his early thinking as “there’s a waste product going into dumpsters and it’s perfect for my cattle, so why wouldn’t I use that?” But, he said, “It’s hard to jeopardize something like a $10,000 animal over a feedstuff.”

“They aren’t hard to find”

Since the passage of the 2018 Farm Bill, which legalized cannabis containing less than 0.3% THC, the rush to make big business out of hemp has exploded. The United States Department of Agriculture estimates, according to its interim final rule establishing the US Domestic Hemp Production Program released in October, that there were 77,844 acres of hemp planted in the United States in 2018; the USDA expects that number to double for 2019.

Hunter Buffington, program director for the Hemp Feed Coalition, told Cannabis Wire that hemp is already ubiquitous in animal products: “It’s everywhere,” she said. “It’s in dog food, in horse food, in cattle feed. Everyone’s eating it, it’s just not gone through the approval process.”

From an economic standpoint, the benefits for farmers are clear, Buffington said: After hemp seeds are processed for oil for human use, for example, the leftover material can retain 20 percent of its fat, including fatty acids, and an average of 30 percent of its protein.

With hemp’s approval as an ingredient in feed, this material could be repurposed for a profit, providing an additional revenue stream for farmers. “We have farmers in general that are struggling to find a cash crop that is reliable and provides them with enough income to continue to farm,” Buffington said. “Utilizing hemp is definitely going to help stabilize our farm economy.”

Regulation and risk

A number of regulatory pathways exist for hemp to be approved for animal feed. One is a food additive petition, which must be submitted to the FDA’s Center for Veterinary Medicine by a manufacturer or “other sponsor.” Another is a “new ingredient definition” submission to the Association of American Feed Control Officials (AAFCO), which still requires a review from the FDA’s Center for Veterinary Medicine Division of Animal Feeds. AAFCO’s Guide to Submitting New Ingredient Definitions notes, “Some ingredients may have animal and or human health concerns and these ingredients are not appropriate for review by AAFCO but need to be submitted through the Food Additive Process to FDA.”

The FDA and AAFCO recommend that both routes include data from controlled feeding trials that show the feed’s safety, and, according to the FDA’s guidance for animal food additive petitions, “scientific data necessary for demonstrating that the residues of the food additives are safe to humans consuming edible products of animals fed the food additive.”

In a statement to Cannabis Wire, the FDA said, “At this time, there are no approved food additive petitions or ingredient definitions listed in the AAFCO [official publication] for any substances derived from hemp” and that they hadn’t received “any Food Additive Petitions or GRAS [Generally Regarded as Safe] notices for any ingredient derived from hemp in animal food.”

Industry groups pursuing paths to legality say there’s no time to spare. At the Hemp Feed Coalition, Buffington said she is working simultaneously on a “new ingredient definition” for hemp seed meal and a Food Additive Petition for hemp seed oil in partnership with a manufacturer, High Plains Nutrition.

One other remaining obstacle to hemp for livestock is a lingering fear among some farmers that conflates hemp with drug use. “There is still a marijuana stigma that comes along with hemp,” Vorhes said. “I would say in my old community, my next door neighbors—they’ll probably never grow hemp because they still think it’s the devil’s lettuce.”

The path ahead

Building on the limited existing studies on hemp feed, Buffington said she is collecting proposals for new research on hemp seed meal, hemp seed cake, and hemp seed oil to generate more data for the Hemp Feed Coalition’s new ingredient definition and food additive petition. She’s received fourteen project proposals thus far, including eight from universities, for six different animal species. Buffington said Wenger Feeds, a poultry and swine-feed manufacturer based in Pennsylvania, has already partnered with the Hemp Feed Coalition to conduct a “full life cycle” study using hemp seed meal fed to poultry for protein, including both broilers and egg-laying hens.

The studies will mount a case for hemp seed meal in poultry feed. Buffington ultimately wants to build evidence, with additional studies and ingredient definitions, that hemp feed is safe for milk-producing cows, beef cattle, and swine.

For now, products like hemp seed meal and hemp seed cake must wait for the regulatory go-ahead. “Because there’s not an approved market for it,” she said, “it very much sits in the warehouse with nowhere to go.”

An industry holds its breath as it works with regulators to approve hemp in animal feed.