This is the seventh article in the “Fix It With Feed” series. Check back every Wednesday for more articles on nutrition and how it affects performance.

In the world of human nutrition, fat is usually a bad word. However, for horses, a high-fat diet can help solve a myriad of issues. Not only will additional fat aid with the obvious issue of weight gain, but it’s also a good source of “cool” energy, may improve skin and coat quality and can even help prevent tying up.

“There are no real negatives to feeding a high-fat diet except the possibility of feeding too many calories,” said Olivia Martin of Performance Feeding. “Feeding a horse to be overweight can trigger other problems such as metabolic disorders and unneeded stress on joints and other structures. However, hard-to-keep horses and highly strung/excitable horses benefit from high fat diets. Horses suffering from conditions such as chronic tying up and Polysaccharide Storage Myophathy also benefit from a high-fat diet.”

Why Feed Fat?

One of the first questions people ask about a high-fat diet for horses is: Is it natural? The answer is no, but that’s no reason to avoid fat.

In the wild, horses would get all the calories and nutrients they needed from grass and other forages. However, today’s sport horses have decreased access to forage and increased caloric demands due to exercise, so they need supplementation in the form of concentrates.

“They aren’t designed to eat fat, but they can cope with it,” said Tania Cubitt, Ph.D., a nutritionist with Performance Horse Nutrition LLC. “Horses don’t have a gall bladder, and in humans, the gall bladder stores bile, which breaks down fat. The liver in the horse produces some bile to break down fat. We have determined through science that they can deal with fat in their diet, and it’s better than feeding high amounts of sugars and starches.”

Fat contains 2.25 times more energy than cereal grains such as corn or barley, so when you increase fat in the diet, you can feed fewer pounds of feed. However, if you’re supplementing fat to your horse’s regular feed, be careful not to cut back too much on his concentrate ration. Commercially formulated feeds only provide your horse with the nutrients he needs if you follow the manufacturer’s recommendations at mealtime.

The digestion of fats does not increase blood sugar, and horses digest fat very efficiently in the small intestine. Given two to three weeks to adjust, horses can digest up to 20 percent fat in their total diet, although it’s only practical to feed them that much in a research setting. (That’s why it’s OK for horses to eat high-fat diets and not humans—a high-fat diet for a human might consist of 60-70 percent of total calories from fat or more!)

In the past, pre-formulated high-fat feeds weren’t as readily available, but today we have many more options. A concentrate ration with 3-4 percent fat may be perfectly appropriate for an easy keeper in light work, but many performance horses benefit from more fat in their diet.

“Fat gives the horse physical energy without increasing mental energy. Feeding fat can also benefit a horse’s skin and coat condition,” said Martin. “The fat content of the ration does not affect the protein needed by the horse. Fat is an energy source only.”

High-fat diets enable horses in intense situations, such as pregnant or lactating mares, or horses working at high levels, to safely and more efficiently meet their energy requirements. In the case of hard-working horses, a horse can use fats to help keep their muscles working during stressful situations.

However, it’s important to remember that horses need time to adjust before they can digest fat easily. If you choose to switch your horse to a high-fat diet, do so slowly and well before a competition so his muscles can use the new source of energy efficiently.

The Omegas

Another benefit of feeding fat is the addition of omega fatty acids into the diet. Omega fatty acids have been shown to benefit humans and other animals in a variety of ways, and studies are just starting to come out that show the benefits for horses.

Benefits may include:

• Increased plasma and red blood cell levels
• Increased semen quality post freezing or chilling in breeding stallions
• Reduction in inflammatory response to exercise
• Improved vitamin E status in horses fed supplemental vitamin
• Reduction in inflammation caused by arthritis

Omega 3 and Omega 6 are essential fatty acids—nutrients that a horse must get from feed rather than producing internally. The horse needs a balance of Omega 3s to Omega 6s, but we don’t yet know what the best ratio is.

“The natural diet of horses—primarily fresh and dried forages—contains more Omega 3 fatty acids than diets consisting of a mixture of forage and cereal grains,” said Martin. “Domesticated horses are often fed concentrated sources of energy in the form of grain meals. Grains possess more Omega 6 fatty acids than forage, creating a balance of Omega 3 to Omega 6 fatty acids that may be inappropriate, especially when diets are high in grain.”

Omega 3s are thought to be anti-inflammatory in the body, and Omega 6s are thought to be pro-inflammatory, and both are necessary. So the idea is not to eliminate Omega 6s from the diet, but to look for ways to supplement Omega 3s, especially for horses with less access to good pasture.

Percentage Of Omega 3s And Omega 6s In Common Fat Supplements
Chart courtesy of Tania Cubitt, Ph.D.

Fish oil is another excellent source of Omega 3s.

Fat Sources 101

Most commercial feeds already have some amount of fat in them, but the level varies greatly depending on the product.

Cereal grains, such as corn and oats, are high in carbohydrates but low in fat.

Oils, on the other hand, are 99 percent fat. Therefore, adding oil to your horse’s diet is one of the easiest methods for increasing fat intake.

Flax seed is another source of fat and may be fed as an oil or ground meal. There are, however, some drawbacks to flax.

“Large amounts of flax aren’t palatable,” said Cubitt. “I recommend it a lot, but more for the Omega 3 fatty acids. For sheer weight gain, you need to feed two to three cups of oil a day on top of a high-fat ration, and for some reason they don’t like the taste of it. And it can be quite costly.”

Another issue with flax is that the seeds must be ground for horses to get the benefit, as they can’t digest the seed coating. “As soon as you grind it, you expose the inside to oxidation and hence rancidity. That’s why you have to put it in the fridge,” said Cubitt. “If you’re going to buy it in bulk, keep the seed in a cool dry place and grind it as needed. Ground flax is not as potent as straight flax oil for calories because it’s got the fiber in there.”

Rice bran is another option for additional fat, and it comes in pelleted or extruded versions. However, it only contains 20 percent fat.

There are also numerous fat supplements on the market. However, it’s important to read the ingredients list. Fat can come from a vegetable or animal source, but animal fat is not as palatable to horses.

Animal fat is only about 75 percent digestible, whereas vegetable fat is 95 percent. In small intakes of fat, the digestibility is insignificant, but when a horse consumes a large amount, such as when he is on a high-fat diet, the fat that isn’t digested can upset the balance of microbes in the hindgut.

It’s fine to feed a small amount of fish oil in order to add Omega 3s to your horse’s diet, but look to the vegetable fats to add substantial amounts of fat.