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Study: Spent Hemp Biomass Safe For Dairy Cows

A recent study has found hemp biomass left behind after extraction of cannabidiol (CBD) is safe for consumption by lactating dairy cows – although the taste may be a little off-putting to the cows initially.

Spent hemp biomass, like other hemp waste products, retains significant nutritional value. But the use of this waste to feed animals still isn’t permitted in many jurisdictions.

There has been increasing research in recent years focused on safety and efficacy to convince regulators to allow it. Just recently in the USA, feeding hemp seed meal to laying hens received tentative approval at the mid-year meeting of the Association of American Feed Control Officials (AAFCO).

Massimo Bionaz, PhD, from the Department of Animal and Rangeland Sciences, Oregon State University led a team studying spent hemp biomass with measurable levels of cannabinoids on the productivity and health of dairy cows.

18 late-lactation Jersey cows were involved in the eight-week study. After being fed the same diet to establish baseline, the cows were split into two groups – one fed increasing levels of feed supplemented with spent hemp biomass and the other a control group receiving alfalfa meal. Both groups had a maximum of 13% dry matter in their feed and the hemp-fed cows were subjected to a 4-week period where the hemp was tapered off.

Measurements taken during the study included:

  • Dry matter intake
  • Body weight and body condition score
  • Milk yield
  • Milk components and fatty acid profiles
  • Blood parameters
  • Nitrogen metabolism,
  • Methane emission
  • Activity levels.

Results indicate that as well as spent hemp biomass being safe as a potential feed ingredient for lactating dairy cows, it did not negatively affect lactation performance or the health of the animals.

But it seems this hemp waste may be an acquired taste as there was a decrease in feed intake observed for the cows in this group.

“Dairy cows are creatures of routine and are likely not accustomed to the characteristic ‘skunk’ smell from spent hemp biomass, especially in its concentrated pelletized form,” said Dr. Bionaz.

However, milk production was unaffected and in what came as surprise to the researchers, it increased compared with the control group after the hemp was removed from the cows’ diets. Another issue identified was spent hemp biomass might compromise liver clearance capacity of dairy cows, but it did not affect the immune system or any other health-related parameters measured except for a possible low-grade inflammation.

The study has been published in the Journal of Dairy Science.

Learn about other agricultural uses for hemp.

Steven Gothrinet
Steven Gothrinet has been part of the Hemp Gazette in-house reporting team since 2015. Steven's broad interest in cannabis was initially fueled by the realisation of industrial hemp's versatility across multiple sectors. You can contact Steve here.

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