A closer look at the effects of feeding oils to horses.

Horse diets have always contained small amounts of oil. But plenty of research and anecdotal evidence suggests horses can utilize higher levels of oil than what they’ve traditionally received.

Horses that are adapted to higher-oil diets are able to digest and transport this extra oil. The evidence lies in increased bile production and elevated levels of lipoproteins in their blood serum (lipoproteins are the proteins in blood that carry oil molecules). Unlike other animals, a horse’s bile is secreted fairly continuously from the liver and passes via a bile duct directly into the duodenum (bile is a salt solution that helps in the digestion and absorption of oils). Horses can then metabolize oils as an energy source through a process called fatty acid oxidation. Hence, horses can efficiently digest, metabolize and utilize quite high levels of oils.

So, what are the effects of oil supplementation in horse diets?

1. Oil is energy dense

Oil is very energy dense. It yields about 2¼ times more energy than starch or protein. This may be useful for a number of reasons, including reduction in gut fill and the reduction in feed intake required to sustain maintenance and exercise.

2. It benefits horses in hot climates

The total amount of heat waste produced per unit of energy is different for different feeds, with oils producing significantly less heat waste than fermentable carbohydrates, roughages and proteins. Oil-supplemented horses in hot conditions have been reported to have lower mean body temperatures than those consuming high roughage and high grain diets.

Further, oil metabolism yields almost twice the water of protein and carbohydrate metabolism. This may benefit horses that sweat profusely.

The combined effects of oil feeding involves reducing thermal load and increasing water production in horses working in hot environments.

3. Oil is a “non-fizzy” feed

When starch (typically in the form of grain) is fed to horses in large quantities, there is a risk of starch overload into the hindgut. This can culminate in “fizzy” or “hot” behavior, which can result in stressful and dangerous situations for both the horse and rider. Replacing some of the grain in feed with oil to provide energy can minimize the risk of starch overload. Oil provides a source of “cool” energy, which is not associated with “fizzy” behavior.

4. It helps in the management of equine rhabdomyolysis (tying-up)

Equine rhabdomyolysis (tying-up) is a broad term used to describe muscle disorders including EPSM and RER. Equine polysaccharide storage myopathy (EPSM) has been associated with dysfunctional carbohydrate metabolism. Horses suffering from this condition must be provided with non-carbohydrate energy sources such as oil. Results indicate a reduction in clinical signs in EPSM horses consuming a high oil, low carbohydrate diet.

Recurrent exertional rhabdomyolysis (RER) is another form of tying-up. Sufferers are frequently fillies, and tend to be nervous. Starch feeding and excitement are both implicated as “triggers” in RER; the partial replacement of grains with oil in the diet may aid in the management of this condition.

5.     Oil positively affects glycogen stores

Once adapted to higher levels of dietary oil, horses can utilize oil for energy during submaximal/aerobic exercise. This is achieved via fatty acid oxidation and has the effect of sparing muscle glycogen stores.

Subsequently, horses appear able to utilize the greater muscle glycogen stores during high intensity/anaerobic activity. This phenomenon has positive implications, such as delaying time to the onset of fatigue and increasing the horse’s capacity for high intensity exercise.

 Coconut or soy oil?

Coconut and soy oils are both “cool and safe” sources of concentrated energy and are fed for conditioning, coat shine and weight gain, or to supply extra energy to the diets of hardworking horses.

Coconut oil

Coconut oil is a highly stable tropical oil, meaning that it’s not prone to rancidity and maintains its nutrient status over long periods. It contains mainly saturated fatty acids of short and medium chain length, which are quickly metabolized and available for use as ready energy for high intensity work. Lauric acid (the main fatty acid in coconut oil) is also associated with having antiviral, antibacterial and immune-boosting properties.

Soy oil

Produced from soybeans, commercially available soy oils are often highly refined and have usually been chemically extracted. Soy oil is rich in long chain fatty acids and contains predominantly polyunsaturated fatty acids, making it prone to rancidity. Most sources of soy oil are derived from GMO soybeans. Soy oil provides a high ration of Omega 6 to Omega 3.

In summary

Both oils are used to maintain condition, encourage weight gain and improve coat condition without making horses “hot or fizzy” in temperament. The composition of coconut oil is very different to soy oil. Where coconut oil is rich in saturated, short and medium chain fatty acids (which are stable and can be rapidly metabolized), soy oil contains higher levels of polyunsaturated, long chain fatty acids (which are less stable and more slowly metabolized).

Both soy and coconut oil can be fed with other hard feeds (i.e. grains). However, they should always be fed in conjunction with ample fiber/roughage feeds (feed at least 1% of bodyweight/day of hay, chaff, etc.).

The benefits of supplemental oil for horses extend beyond their use as a grain alternative. Oil supplementation can help prevent fizzy behavior and various types of tying-up, and reduce the thermal load on horses in hot climates. It can even provide energy for submaximal work and may increase capacity for high intensity exercise. High oil feeds such as Cool Stance are a palatable and no-mess way of providing horses with supplemental oil and gaining the subsequent advantages associated with oil feeding.


Dr. Kempton is a nutritional biochemist and an equine enthusiast who understands the practical aspects of the effect of a good diet on performance horses. His philosophy is that since horses don’t read nutrition books, they can only eat what humans think they need. Horses can tell us if their diet is suitable through their coat, eyes, behavior, performance, and onset of more serious metabolic disorders. Grain based feeds with a high sugar and starch content may be convenient for us, but they are not suitable for horses. Dr. Kempton pioneered the development of equine feeding systems based on the unique benefits of coconut oil. stanceequine.com

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