Feeding Flaxseed to Horses: New Research

Long ago, horsemen fed linseed, now commonly known as flax or flaxseed, to their horses as a way to improve skin quality and to achieve a glossy coat. While studies have delved deeper into the use of linseed oil in equine diets, little time has been spent on researching linseed meal and other by-products of oil production.

Because of this, researchers set out to determine the digestibility and safety of two diets that contained linseed groats.^* Groats are hulled, and sometimes crushed, grains or seeds, such as oats, wheat, and linseed.

In this study, two different supplements were formulated with linseed groats: (1) 70% linseed groats, 15% dehydrated carrot, 10% dried garlic, and 5% molasses, and (2) 65% linseed groats, 15% molassed sugar beet pulp, 10% dried garlic, 5% dehydrated carrot, and 5% molasses.

Horses were fed at a maintenance energy level, with a forage-to-concentrate ratio of 70:30. Oats comprised the majority of the concentrate portion, though about 8% of the oats was substituted with the experimental supplements in the treatment diets. All diets contained the same amount of energy.

Blood samples were collected from the jugular vein to evaluate the possible effects of the supplemented diets on the health of the horses. Blood was analyzed for red blood cells, white blood cells, hemoglobin, hematocrit, and fibrinogen. Liver enzymes were assessed to measure the possible harmful effects of cyanogenic glucosides, which are naturally found in linseed and have kept horsemen from feeding linseed in the past.

Compared to the control diet, researchers found the supplemented diets had higher digestibility of crude protein. There were no differences in the blood parameters between the treatments. Therefore, they concluded that linseed by-products combined with other fiber sources can be used for horses, especially when the intent is to reduce starch content.

Most modern feed manufacturers include high-fat and high-fiber ingredients in their low-starch feeds. Rice bran and vegetable oil are used to increase fat content, while beet pulp and soy hulls boost fermentable fiber.

“To ensure your horses are optimally nourished, choose an expert-formulated feed from a reputable feed manufacturer,” said Catherine Whitehouse, M.S., a nutrition advisor for Kentucky Equine Research. “Coupled with forage, these feeds supply all of the necessary nutrients for peak health and feature top-grade ingredients.”

Linseed is rich in the omega-3 fatty acid alpha-linolenic acid (ALA), which is synthesized to longer-chain polyunsaturated fatty acids, such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Both DHA and EPA have multiple health benefits to horses.

“For optimal supplementation of DHA and EPA, choose a marine-derived supplement such as a research-proven fish oil,” Whitehouse recommended.

^*Saastamoinen, M., and S. Särkijärvi. 2020. Effect of linseed (Linum usitatissimum) groats-based mixed feed supplements on diet nutrient digestibility and blood parameters of horses. Animals 10:272.