Can hemp industry by-products provide viable animal feed?
Industrial hemp is showing promise as a sustainable animal feed, but its journey to widespread use is a tricky one.
The shift towards the legalization of cannabis and growing demand for cannabinol (CBD) products means the market for industrial hemp (Cannabis sativa) is one of the fastest-growing in the world.
With its ability to sequester carbon in the soil, resilience to pests and multiple uses, and spent hemp biomass being used for fuel, medicines and fibres, the crop has been identified as a promising renewable resource. And now, a growing body of research suggests the crop has potential to be a sustainable source of commercial feed for livestock production too.
Hemp helps lambs’ digestion
Work led by agricultural scientists at Oregon State University showed that including a proportion of hemp biomass in the diets of finishing lambs has no effect on production, meat quality or the health of the animals.
The nutrient content of hemp is comparable to alfalfa, the researchers found, making it a viable alternative, while other benefits were noted including an antioxidant effect and improved digestibility.
“Based on our initial data, while on paper [spent hemp biomass] is an excellent feed, it is not as palatable. This is an important limitation that likely would affect the market for the biomass,” said Massimo Bionaz, one of the authors of the work.
“However, it is also possible that we will solve the palatability issue and, if so, it can become a great alternative to alfalfa.”
At present, many processors are willing to provide spent hemp biomass at almost no cost, Bionaz explained, but once it becomes a “legitimate feed”, market forces will decide its value.
Exploring potential for cattle
Researchers at North Dakota State University have also been focused on the effects of feeding hempseed cake to young cattle.
In work published in 2022, the researchers showed that including 20% hempseed cake in a corn-based finishing diet for heifers decreased growth performance compared to a diet using 20% distillers’ grains. However, the diet did provide adequate nutrition and satisfactory performance overall, and offers an option for producers, dependant on availability and cost, they said.
In follow-up research, the team fed similar diets, plus a control, to finishing steers to establish the effects of hempseed on the use of nutrients by the animals. They found that the hempseed diet reduced digestion of organic matter compared to the other diets, but improved nitrogen digestibility.
“Although these data may suggest that feeding hempseed cake could increase nitrogen balance, further research is needed in diets differing in dietary crude protein, ruminally degradable protein, and starch concentrations,” they concluded.
“Overall, these data suggest that hempseed cake is a potentially useful alternative feed ingredient for finishing cattle diets.”
Battling political blockades
Despite promising results, legislation is currently lagging behind. In the US, despite industrial hemp no longer having the status of a controlled drug, the Food and Drug Administration (FDA) has banned its use as animal feed or pet food. Industry body the Hemp Feed Coalition is piling on the pressure, however.
In a letter to FDA advisors the Association of American Feed Control Officials (AAFCO) has called for hemp to be ‘grandfathered’ into the 1958 Federal Food, Drug and Cosmetic Act, due to evidence suggesting that hemp products have been safely used in feed products from the early twentieth century.
Without such an intervention, they said, at the current rate of approval “it will be millions of dollars and decades before the hemp industry even has a chance to compete in the greater feed market.”
Going beyond hemp ‘waste’
The situations is slightly different in Australia, where hemp stalks and denatured industrial hemp seed can be used as feed for livestock. For some, though, the feeling is that things could go further.
Proof-of-concept research is being publicly funded in Western Australia, which moves beyond a focus on spent hemp biomass, to consider the impact of ruminants feeding on the whole plant, either through direct grazing or use as forage.
In the first phase of the work sheep were fed all parts of hemp plants left over after the crop had been harvested for its seed, with performance compared to oaten straw and cannabinoid residues in the animals’ tissues recorded.
The data found a hemp diet wasn’t detrimental to any performance metrics, with liveweight gain slightly improved. Residues of tetrahydrocannabinol (THC), the psychoactive substance found in Cannabis sativa, were found in animal tissues, but at very low levels; the researchers suggested that management practices, such as a clearance period, could allow animals to go to market meeting the zero-THC requirements regulators demand.
“There may also be scope for Food Standards Australia New Zealand to set a maximum allowable limit for THC in animal products in the future as more data becomes available,” they added.
The next phase of the research aims to add greater understanding around nutritional value, cannabinoid half-life in sheep and cattle, as well as clearance pathways and timing.
Green lights ahead?
Feeding livestock hemp, like many seemingly-radical ideas in farming, is less a brand-new concept and more a revival of a practice carried out without much analysis in years gone by.
Regardless of the idea’s origins, though, concerns about THC in food aren’t looking likely to go away any time soon. This view is the driving force behind why the situation in Europe regarding hemp-based feed looks much the same as the US.
While research to date has demonstrated hemp’s promise, it has not showed it to be essential for inclusion in animal diets, either from a point of view of nutrition or economic necessity. It may be that this contributes to the seeming lack of urgency around bringing this useful feed to new markets.
But assuming more data pours in, the hemp industry at large continues its upwards trajectory, and persuasive arguments keep being made, it remains an alternative feed to watch in coming years.
This article first appeared on Farming Future Food
