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Student research looks at digestibility of industrial hemp cake in cattle

Aletta Husmann is an undergraduate Animal Science major at South Dakota State University.
Courtesy photo
Aletta Husmann is an undergraduate Animal Science major at South Dakota State University.

Hemp processing also creates a byproduct. And a South Dakota State University student wonders if there’s a use for that byproduct in agriculture.

Hemp is newly legal in South Dakota, and demand is growing. The non-intoxicating cousin of marijuana is useful in human food, fiber and other products.

It all began with a question no one could answer.

“I asked what people were doing with it, and nobody could really give me an answer, so that provoked my own research about what hemp was good for,” explained Aletta Husmann

That’s undergraduate Animal Science major Aletta Husmann. She became curious about the uses for industrial hemp when she learned an industrial hemp processing plant was being constructed near Willow Lake, South Dakota.

Through online research Husmann learned about hemp cake. Hemp cake is a byproduct from industrial hemp processing that can contain between 20 and 40 percent crude protein. And this fact gave Husmann an idea.

“I thought, you know, this may make a good feedstuff,” Husmann said.

After a bit more digging she learned there wasn’t much research on hemp cake as a livestock feed. The reason? Let’s have Husmann’s Animal Science Professor Cody Wright explain.

“Industrial hemp and hemp byproducts have not been approved by either the FDA, the Food and Drug Administration’s Center for Vet Med or an organization called AFCO, The Association American Feed Control Officials,” Wright said.

Wright said that the approval process is extensive and can take years.

“You have to essentially provide evidence that the product is not going to harm the animals. There’s not going to be residue that going to affect humans. All those kinds of things. So, I think it’s just a matter of time before somebody can provide that evidence so they can make an informed decision,” Wright said.

Eager to find an answer to her question – does hemp cake make a good feedstuff – Alletta Husmann wants to help out. She is in the preliminary stages of her own research project.

“I am researching the effects of industrial hemp cake on rumen microbiology in cattle,” Husmann said.

Now in case you are wondering what a rumen is – it’s the name for the uniquely designed stomach of some animals, like cows and sheep.

Cody Wright.

“A lot of people will have heard at one point in time that a cow has four stomachs. And that’s really not true. They have one stomach. It just has four compartments. In the first two chambers in particular there’s a substantial microbial population. They reside there and what those bacteria and protozoa enable the animal to do is utilize fiber from various feeds they consume like grass or hay or silage. Those feeds would not be useful for non-ruminant. That’s why we don’t feed hay to pigs,” Wright said.

To better understand how the rumen’s microbial population will react to industrial hemp cake, Husmann will actually collect fluid samples full of these microbes from the stomach chamber of a cannulated cow.

“A cannulated cow is a cow that has a surgical passageway connected from the outside world into the rumen. So, it’s kind of like a little portal. … Then I’m going to feed the rumen microbes and assess the changes in the microbial populations before and after eating the cake,” Husmann said.

Husmann says she is eager to learn what her research says about digestibility of hemp cake.

“If the demand for hemp seed oil is on the rise, this byproduct is going to need a home and a use. And the surplus will hopefully make it cheap enough for farmers and rancher to feed hemp in place of other feedstuffs – or just as good quality protein,” Husmann said.

If the FDA approves industrial hemp cake based on research that shows it is a safe feed option, this could have a positive impact on the more than 16,000 South Dakotans who raise cattle explains Cody Wright.

“Ultimately it comes down to cost of production. Cost of gain, types of factors, and if we can identify a feed stuff a feed ingredient that we can utilize and it helps us save a few dollars per ton, even 10s of dollars per ton, that’s just a benefit to the producers. So hopefully, you know that byproduct feed that comes out of the industrial hemp industry is something that is usable. Man, if its fairly inexpensive, all the better,” said Wright.

Husmann is currently seeking funds to support her research. She hopes to finally have some answers by the end of this summer.

Lura Roti grew up on a ranch in western South Dakota but today she calls Sioux Falls home. She has worked as a freelance journalist for more than two decades. Lura loves working with the SDPB team to share the stories of South Dakota’s citizens and communities. And she loves sharing her knowledge with the next generation. Lura teaches a writing course for the University of Sioux Falls.