Recently, research conducted by Oregon State University showed promising results when feeding spent hemp biomass to cows.
The nutritional profile of hemp can be used to make stock feed after the extraction process. The waste is high in protein and contains essential fatty acids. It could be used to replace soybean or alfalfa, as it has a similar amino acid profile. This waste contains phytochemicals that have antioxidant, antiinflammatory and antimicrobial qualities.
But in many jurisdictions use of spent hemp biomass in such a way is still banned; primarily due to concerns about the potential presence of delta-9 tetrahydrocannabinol (Δ9-THC) winding up in products such as meat and milk. As a feed component, hempseed meal has been legalized in only a few nations.
Oregon State University researchers have studied the amount of cannabinoids that accumulate in the milk and tissue of dairy cows who are fed with spent hemp biomass. The project included 18 Jersey cows. Nine of them were given a diet that contained 13% spent cannabis biomass and nine others received an alfalfa-based control diet. All cows were then given the control diet for a period of four weeks.
In the first few days after the withdrawal of the cannabinoids, cannabinoids were detected in tissues and the milk of the dairy cows. However, less than 1% of the cannabinoids transferred into the milk. However, a high accumulation of THC was detected in adipose tissue (fat).
But twelve days after withdrawing spent hemp biomass as feed, Δ9-THC in milk was undetectable. It was detectable at this stage in the adipose tissues, but it didn’t disappear until 30 days following withdrawal.
Researchers also found that CBD-acid and CBD in plasma from cows 90 days post-calving.
This study provides the necessary data for FDA approval for spent hemp biomass to be used as an animal feed supplement. said Massimo Bionaz is the lead author.
This research was published in May 2025 Journal of Agricultural and Food Chemistry
Currently, spent hemp biomass has little to no economic value for hemp producers — allowing it to be fed to cows could be a game-changer and a win-win for all.