Hempseed for Horses: Definition,
Nutrient Composition, & Evidence
Written by Isabelle D’Costa, Equine Nutritionist MSc, of Honos Nutrition Co.
Hemp is one of the most ancient cultivated crops, grown for years for uses such as textile fiber and hempseed (CFIA, 2019). Recently, it has been gaining attention due to the nutritional value of hempseed (Farinon et al, 2020). Hempseed ingredients boast high levels of protein, fat and digestible fiber, and with a unique fatty acid profile, these may have great potential for both livestock and human nutrition! Ingredients of interest for animal nutrition include hempseed oil, hempseed cake/meal, hempseed fines, and hempseed hulls. Research in various animal species has reported beneficial effects on cardiovascular and kidney biomarkers, reduced intestinal permeability, improved nutrient profile of milk, eggs, and offspring health, and changes in tissue fatty acid composition (Richard et al, 2007; Vastolo et al, 2021; Ely et al, 2023; Lanzoni et al, 2024). As more research emerges on this crop for use in nutrition, hempseed ingredients are now becoming increasingly available as supplement options for use in the equine diet.
What is hemp?
Hemp is a cultivar of the C. sativa L. plant, and is commonly confused with drug-type hemp, cannabis, despite distinct differences. Cannabis that contains high cannabinoid content, which elicits psychoactive effects, and makes up what is commonly known as marijuana. Industrial hemp, commonly used for fibers, is genetically different from drug-type hemp, also called cannabis, and as a result, cannabinoid levels in industrial hemp are extremely low.
Industrial hemp must contain less than 0.3% THC in North America (CFIA, 2019). To enforce this, industrial hemp crop is regulated by Health Canada, and producers have regulations to follow, such as a required crop sampling
and testing for THC concentration (Government of Canada, 2018). It is important to distinguish that the hempseeds themselves do not contain any cannabinoids, as these compounds are only present in leaves and stems, not seeds. As such, the only exposure that hempseed has to cannabinoids is during harvesting and the cleaning process of the seed (Farinon et al, 2020).
Since industrial hemp already has low levels of THC due to further selective breeding (Richard et al, 2007), contamination of the hempseed is even less likely, and proper practices should protect against contamination of hempseed.
Research conducting cannabinoid analysis of the serum and synovial fluid of horses consuming hempseed oil reported that cannabinoids were undetectable to 50 parts per billion (Ely et al, 2023). While assessing palatability, Springer et al (2023) reported that feeding 1 kg/day was safe in horses, which is a suitable maximum feeding rate when fed as a supplement in the diet. As with any feed ingredient or supplement, selecting a company with high quality standards, certifications and transparency regarding detectable levels is strongly recommended.
Nutrient Composition of Hempseed Supplements for Horses
Some hempseed ingredients are very nutrient dense, and the nutrient profiles can vary depending on the form. A versatile feedstuff, it can be consumed as whole hulled seed, or dehulled (hemp nuts, hemp fines), or in further products such as oil, flour and protein powder (Farinon et al, 2020). Hemp nuts are the soft insides of hemp seed, while hempseed fines are produced by dehulling hemp seeds, and are small pieces of hempseed and hemp shells. Similar to hemp nuts, this feedstuff is high fat and protein, but contains 5-10% fiber compared to hemp nuts. These feedstuffs also offer a concentrated source of digestible energy, ranging from 4.7 to 5.0 Mcal/kg, due to the high concentrations of fat found in the seed.
Hempseed products can contain high fiber depending on the inclusion of hempseed hulls (the outer coating of the seed), and based on existing data, this fiber fraction is similar to good quality hay. NDF, a common measure of plant digestibility in horses and other livestock, is reported to range from 29.7 to 44% in hempseed products. With the typical hay ranging from 40-65%, hempseed presents a digestible fiber portion for livestock species, with the
potential to offer an alternative fiber source in the diet as well (Bailoni et al, 2021; Springer et al, 2023;Springer et al, 2023b). Existing qualities of hempseed products suggest that the fiber content is comparable to commonly fed feedstuffs, and could suit the equine digestive system.
Fat content in hempseed ingredients can range from 10.7-99% fat, depending on physical form and processing (Bailoni et al, 2021; Springer et al, 2023). Hempseed is a rich source of omega-3 fatty acids (Necib et al, 2022), and supplementation in other species has also been reported to significantly increase total plasma levels of essential fatty acids ALA and LA (Richard et al, 2007). Also of interest, hempseed has an omega-3:6 ratio of 1:3, which is a better source of omega-3s than many other plant-based alternatives. In addition, hempseed is well-known for containing GLA, an omega-6 fatty acid with anti-inflammatory properties – this unique fatty acid is not supplied by other common plant omega-fatty acid sources in the equine diet (Farinon et al, 2020). While omega-6 fatty acids are commonly thought of as inflammatory, they are still essential, and GLA may be a useful example of how much so!
GLA is more efficiently converted into anti-inflammatory fatty acid forms than the omega-3 fatty acid ALA and omega-6 fatty acid LA, which are present in high levels in oils such as flax and camelina. This efficient conversion is incredibly important – to promote reduced inflammation in the animal via dietary fatty acid supplementation, alterations in tissue fatty acid profiles are needed (Ely et al, 2023). Existing research on GLA in equine nutrition has been promising. A 2023 study feeding hempseed oil to mature horses reported that GLA was detected in synovial fluid of joints after 28 days of supplementation, and that its converted form, DGLA, was also significantly higher than unsupplemented horses (Ely et al, 2023). Pagan et al (2022) reported that feeding an omega-3 supplement containing GLA resulted in reduced prevalence and severity of ulcers in horses, compared to a fatty acid supplement containing only ALA and LA.
Research has suggested that some omega fatty acids are better than others at modifying these tissue profiles. Supplementation with flax for 90 days did not modify fatty acid composition as thoroughly or efficiently as marine- sources of omega-3s, which require less conversion than the fatty acids in flax (Ross-Jones et al, 2014), so all fatty acid supplementation is not considered equal.Marine-sourced omega-3 fatty acids, containing long-chain fatty acids EPA and DHA, have more evidence in eliciting an anti-inflammatory benefit.
As short-chain fatty acids such as ALA and LA from flax, camelina, and other commonly fed plant-based oils are not as efficiently converted to elicit mediators associated with anti-inflammatory properties, GLA is an exciting alternative, especially for horse owners who are not comfortable with marine sources, or for horses who do not find marine-sources palatable.
Hempseed has also been described as a high quality protein source. With crude protein ranging from 24.8-34.9%, and the presence of all essential amino acids, hempseed ingredients may have potential as protein supplements as well. Studies have reported that hempseed also contains an amino acid composition similar to mainstream quality protein sources for livestock, such as soybean (Bailoni et al, 2021). Soybean meal is commonly considered one of the best quality protein for horses due to its amino acid composition, and hempseed compares well, with similar or higher concentrations of most amino acids, with the main exception of lysine (Bailoni et al, 2021; Farinon et al, 2020). As lysine concentrations can be low in grass hays, but more than sufficient in legume hays such as good quality alfalfa, thoughtful ration formulation is key when incorporating hempseed products into the equine diet. Nonetheless, with strategic use in the diet, hempseed may be a useful feedstuff to supplement protein to horses.
Emerging research in horses has established good palatability when compared to other common, mainstream feedstuffs. A 2023 study (Springer et al, 2023) investigating the palatability of a hemp product compared to rice bran pellets, beet pulp pellets and soybean meal reported that consumption of the hemp product was higher than both beet pulp pellets and soybean meal, but not different than rice bran meal. However, rice bran meal can hold high NSC (sugar + starch) content, yielding it unsuitable for horses requiring low- NSC diets due to existing health concerns. Hempseed products have been reported to have NSC content of 6.5% on a dry matter basis (Springer et al, 2023), and could offer a palatable, safer alternative for horses with metabolic disorders or requiring a NSC-controlled ration. Based on this study, as a feed ingredient, hempseed seems to offer a palatable option for equine diets, with a reduced NSC content compared to other highly palatable ingredients.
Considerations for selecting and using hempseed in your horse’s diet
When considering hempseed ingredients for your horse, use the same careful selection process you would any time you are adding a supplement to your horse’s diet: consider the source, suitability, and stay mindful of overall diet balance.
Hempseed ingredients are not approved for use in equine feeds, and instead are only allowed as supplements under Health Canada, as a Veterinary Health Product (supplement). A veterinary health product can be used to maintain or promote health, but not for use to treat, prevent or cure disease (CFIA, 2019). Be wary of any product which claims to be anything other than a VHP, as this indicates that they are not operating within regulations.
These products must also follow Good Manufacturing Practices, follow Food and Drug Regulations, and contain ingredients from a permitted list.
Hempseed, hempseed oil and hempseed protein are all permitted in VHP, as long as they contain <10 ppm THC, zero detected CBD and produced in compliance with the Industrial Hemp Regulations (Government of Canada, 2024).
Hempseed is a natural source of the following minerals, as well as natural forms of Vitamin E (Farinon et al, 2020):
● Phosphorus: 890-1170 mg/100g
● Potassium: 252-2821 mg/100g
● Magnesium: 237-694mg/100g
● Calcium: 9 – 955 mg/100g
● Zinc: 4-11 mg/100g
● Iron: 4-240 mg/100g
● Manganese:4-15mg/100g
● Copper: 0.5-2 mg/100g
● Alpha-tocopherol: 5mg/100g
Depending on soil trends and growing conditions, hempseed may contain some mineral imbalances (Farinon et al, 2020). This is the case for many forage, plant-based or unfortified supplements, so maintaining careful consideration of overall diet balance is recommended. Ensuring the presence of adequate mineral fortification in the diet through using a well-formulated vitamin/mineral source can help correct many common imbalances present in equine diets!
Summary
In summary, hempseed ingredients can offer a palatable, low-NSC option for supplementing fatty acids and protein into your horse’s diet. Researchers have compared hempseed products nutritionally to flaxseed (Lanzoni et al, 2024), with the added potential benefit of GLA content.
Driving calories through low-NSC fiber and fat pose less risk for digestive disturbances than high-NSC calorie sources, which can promote the maintenance of digestive health. While more research is required to fully understand the potential of the anti-inflammatory fatty acid GLA in supporting equine digestive health, the anti inflammatory and bioavailable properties observed with GLA may offer additional benefit.
When considering adding a supplement to your horse’s diet, be sure to consider supplement source and stay mindful of total diet balance. Selecting a product with high quality standards, and transparency regarding detectable levels can help you ensure you are providing a quality supplement to your horse!
References
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Written by: Isabelle D’Costa, MSc
Isabelle is an independent equine nutritionist who owns Honos Nutrition Co., and is based in Ontario, Canada. Honos Nutrition Co has supported horses and their humans all over North America. With a Master of Science in Equine Nutrition, Isabelle is passionate about connecting equine caretakers with applicable evidence-based solutions and tools for improving the lives of horses.