Can Hemp Hay Work as Sheep Feed? New Research Offers Clues

Could industrial hemp become a useful feed crop for sheep? Answering that question requires looking beyond the nutrients listed in a laboratory report. Sheep depend on microbes to turn plant material into usable energy, so a promising feed ingredient must work with that living digestive system.

A new study accepted in Small Ruminant Research examines what happens to those microbes when sheep eat pellets containing industrial hemp hay.¹ Researchers found changes in microbial community composition, although overall microbial diversity within samples did not significantly change.

The findings offer a more detailed picture of hemp’s agricultural potential. They also suggest that developing successful hemp feeds will require matching the plant material, inclusion rate, and overall diet to the animal’s digestive needs.

Why Sheep Feed Depends on Gut Microbes

Sheep are ruminants, animals whose digestive systems include a fermentation chamber called the rumen. Microorganisms there help break down plant material that the animal could not efficiently digest alone. Their activity produces volatile fatty acids, which provide usable energy.

Think of the rumen as a workshop staffed by different specialists. Some microbes help dismantle fibrous plant structures, while others process the resulting compounds. Changing the incoming material can change which specialists thrive and what the workshop produces.

Hemp makes this especially interesting because its potential feed ingredients vary substantially. Hay containing harvested plant material differs from hempseed cake, the residue left after oil extraction, and from biomass remaining after cannabinoid extraction.

MyCannabis’s recent coverage of hempseed and livestock reproductive health illustrates another dimension of this research. Different materials and biological outcomes require their own evidence. A promising result for one hemp ingredient does not establish the value of every other form.

How the Hemp Hay Feeding Study Worked

The researchers used 12 approximately two-year-old Merino ewes from the same flock. They assigned six to a control diet and six to a pelleted diet containing 42% industrial hemp hay.

After a six-day transition, the sheep received their assigned diets for 21 days. Pelleting prevented selective eating, helping ensure that the animals consumed the complete formulation rather than choosing particular ingredients.

The diets were formulated to provide similar energy and protein, but they were not otherwise identical. The control contained barley straw, while the hemp diet included hemp hay and different proportions of other ingredients.

On the final day, the team collected rumen fluid and faecal samples after feeding. They used 16S rRNA gene sequencing, a method that identifies microbial groups from characteristic genetic sequences.

This provided a snapshot of which microorganisms were present and their relative abundance. It did not directly measure everything those organisms were doing, and sampling only at the endpoint could not reveal how the communities changed throughout adaptation.

What Changed in the Sheep Gut Microbiome?

The researchers examined two kinds of diversity. Alpha diversity describes the richness and distribution of microbes within a sample. Beta diversity compares community composition between samples.

Neither rumen nor faecal samples showed a significant difference in alpha diversity between diets. However, community composition differed. Returning to the workshop analogy, the range of specialists remained broadly comparable, while the balance of workers changed.

In faecal samples, the hemp diet was associated with a higher relative abundance of Firmicutes and lower relative abundances of Bacteroidota and Spirochaetota. In the rumen, differences appeared among narrower microbial groups, including increases in Olsenella and Eubacterium_hallii_group.

These names describe organisms, not a scorecard of animal health. An increase in a microbial group does not automatically establish better digestion, stronger immunity, or improved production. Relative abundance also describes proportions, rather than proving an increase in the absolute number of organisms.

The digestibility measurements above are reproduced in the paper from the team’s earlier 2022 feeding study. They provide context for the new microbiome analysis and should not be presented as newly generated findings. The fibre digestibility differences were statistically significant; the dry matter digestibility difference was not.

Why Fibre Digestion Matters for Hemp Feed

The earlier results reveal an important distinction. The sheep digested a similar proportion of the complete diet’s dry matter, yet digested less of its measured fibre fractions when receiving the hemp formulation.

Neutral detergent fibre and acid detergent fibre are laboratory measures of plant cell-wall material. Their lower digestibility means that less of those fractions was broken down. It does not mean that digestion of the entire ration declined by the same amount.

One possible explanation involves changes in microbial activity, but the experiment cannot isolate that mechanism. The formulations also differed in starch, fibre, polyphenolic compounds, and other ingredients. Those differences could influence both digestion and microbial composition.

A separate 2026 laboratory study of cannabinoids and rumen fermentation found that THC and CBD impaired some digestibility measures under its experimental conditions. That supports investigating cannabinoid exposure more closely, but a laboratory incubation cannot establish the effects of a complete ration in a living sheep.

The practical opportunity is therefore to improve formulation. A lower inclusion rate, different harvest stage, or different balance of accompanying ingredients could produce another outcome. This study did not test which option would work best.

Hemp Feed Needs Ingredient-Specific Evidence

The broader lesson is that “hemp feed” is too broad a label to predict performance. Seed-derived ingredients, flowering hay, and extraction residues can differ in nutrients and cannabinoid content.

A 2026 study evaluating hemp hulls and screenings as ruminant feed examined animal performance and cannabinoid residues. It found residues in some sampled tissues despite their absence in others. That makes an important point: microbial compatibility, animal performance, and food-product residues are separate questions requiring separate measurements.

Likewise, MyCannabis’s reporting on hemp variety and row spacing shows why the agricultural starting material matters. Growing decisions influence the crop available for processing. Feed development must account for that variability rather than assume every batch of hemp hay has the same properties.

There is a useful parallel in research on sugarcane compost for hemp cultivation: replacing an established input requires evaluating the whole system. An alternative can offer value while still requiring changes in management.

Turning Microbiome Findings Into Practical Feed Research

For hemp growers, livestock feed could eventually provide another agricultural outlet. This experiment does not establish the economics of that market, but it helps identify what a dependable product would need to demonstrate.

The commercial question is not simply whether sheep will eat hemp. It is whether a defined ingredient can deliver predictable nutrition and acceptable outcomes at a useful cost. Consistent composition may ultimately matter as much as total biomass yield.

The next research priorities are straightforward:

• Test several hemp inclusion rates in more closely matched diets.
• Follow larger groups for longer, with repeated microbial sampling.
• Measure digestion, animal performance, health, and residues together.

These steps would help separate adaptation from persistent effects and show whether microbial changes explain meaningful differences in production. They would also clarify whether the 42% formulation studied here represents an appropriate target or simply one experimental starting point.

The encouraging contribution is greater precision. Hemp is becoming a crop whose different uses can be evaluated through specific biological questions. For sheep feed, the next question is which combination of hemp material and diet supports reliable digestion over time. Answering it would move the discussion from potential toward a genuinely useful agricultural ingredient.

References:

¹ Stevens, S. A., Pant, S. D., Blake, B. L., Dods, K. C., & Krebs, G. L. (2026). Investigation into the influence of feeding a pelleted diet containing industrial hemp (Cannabis sativa L.) hay on the ruminal and faecal microbiota of sheep. Small Ruminant Research. Advance online publication. https://doi.org/10.1016/j.smallrumres.2026.107936