You’ve probably heard about the health benefits of omega-3 fatty acids from fish oil, but does this supplement work for horses?

Fish oil is often added to diets, both human and animal, as a source of the essential omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA).

These two omega-3’s have gained a lot of attention because they can promote beneficial physiological changes in horses including: [1]

  • Improved skin and coat quality
  • Reduced inflammation
  • Weight management
  • Support for joint health
  • Improved respiratory health

Omega 3’s are a type of long-chain poly-unsaturated fatty acid (PUFA) that play an important role in equine physiology. Compared to pro-inflammatory omega 6’s like linoleic acid (LA), omega 3’s have an anti-inflammatory effect within the horse’s body.

If your horse’s diet is too high in omega 6’s, feeding fish oil could improve the omega 3:6 ratio and support a healthy inflammatory response. However, some question whether horses should be fed fish oil because they are herbivores and would not naturally eat fish.

Should You Give Fish Oil to your Horse?

Horses naturally obtain another omega-3 fatty acid – alpha linolenic acid (ALA) – from their forages and grains like flaxseed. But in order to have a beneficial effect, ALA must first get converted into EPA or DHA.

Horses can convert ALA to DHA and EPA, but this process is inefficient and does not produce sufficient DHA and EPA to confer the purported health benefits. For this reason, directly supplementing the equine diet with DHA and/or EPA is preferable.

Feeding your horse fish oil is one way to supplement their diet with DHA and EPA. Compared to plant sources which contain minimal or no DHA and EPA, fish oil is rich in these beneficial fatty acids and provides a favourable ratio of omega-3 to omega-6 fats.

However, fish are not naturally a part of the equine diet and fish oil can have a strong odor which raises palatability issues for some horses. Fish oil also has a higher cost per serving compared to other fat sources used in the equine diet.

Other marine sources, such as microalgae, are an alternative that provide high levels of DHA without the adverse odor. Microalgal DHA can be top-dressed on the horse’s feed with minimal palatability concerns.

Mad Barn’s W-3 oil provides 1,500 mg of microalgal DHA and 1,000 mg (1,500 IU) natural vitamin E in a typical serving. This supplement is a good choice for horses that require more energy in their diet to support exercise performance or healthy weight gain.

As with all dietary changes, we recommend consultation with an equine nutritionist to determine what is best for your horse. You can submit your horse’s diet and one of our equine nutritionists will provide a complementary assessment.

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Effects of Fish Oil in Horses

Feeding DHA and EPA can support numerous benefits in horses, including promoting skin and coat health, enhancing joint comfort and improving performance.

Fat is a denser energy source compared to carbohydrates and is metabolized more efficiently. Fat is considered a “cool” energy source, as it has a lower heat of digestion compared to protein and doesn’t promote hot or reactive behavior like starches/sugars.

Before we consider the known palatability issues of fish oil, let’s take a look at the proposed benefits of fish oil supplements in horses.

Improved Exercise Performance

In one study, 10 horses (a mix of Thoroughbreds and Standardbreds) were given either fish oil (containing 8% DHA and 10% EPA) or corn oil (containing 0.3% DHA and 0.05% EPA). The oils were given at a rate of 324 mg per kg of body weight for nine weeks. [3]

The horse’s daily exercise intensity increased over the nine-week period, leading to a final exercise challenge day when horses were assessed while at a moderate gallop on a treadmill.

During exercise