Nutrition Part 2: Fat
What role do omega-3 and omega-6 fatty acids play
in your horse’s diet?
Feeding fats has become a hot topic in equine nutrition over the last several years. This began when scientists identified the role of nutrition in the muscle
disorder PSSM (Equine Polysaccharide Storage Myopathy) and other related conditions. Fat has been touted as a source of “calm energy,” weight gain, and shiny hair. Recently, omega-3 and omega-6 fatty acid ratios have also been in the news for horses as well as humans. In order to understand this evolving facet of equine nutrition, we need to review some basics.
Fat is not a large component of forages, so it is not truly a natural feed for a grazing herbivore like the horse. However, it is easily digested and, if added gradually, can be fed in quantities as high as 20% of the total ration. Fat undergoes
enzymatic digestion in the small intestine of the horse and is broken down into its components, fatty acids. In humans, high-fat diets have been associated
with coronary heart disease and other health problems, but these types of problems have not been seen in horses.
Fat has several advantages as a feed for horses. It is extremely calorie-dense and can be used in place of heavy grain feeding for weight gain or maintenance.
By decreasing sources of grain and carbohydrates in feed, you can avoid resultant digestive upsets and colic. High fat diets also tend to keep horses quieter than starch- or sugar-based diets. Added oil in feeds may increase the amount of oil secreted by sebaceous glands in the skin, resulting in an oilier (glossier) coat.
Sources of dietary fat are very similar in terms of the energy they provide, because all fats are extremely high in digestible energy (almost twice that of carbohydrates). However, fat sources vary in their content of omega-3 and omega-6 fatty acids. Some oils, such as corn oil and sunflower oil, are high in omega-6 fatty acids but lower in omega-3. Others, like flaxseed or fish oil have higher omega-3 content than omega-6. In humans and other animals, increasing
the ratio of omega-3 to omega-6 fatty acids decreases inflammation. This is now being studied in horses, with the hope that it could help us treat many inflammatory conditions such as laminitis, arthritis, and others. Although there has been little conclusive evidence for the value of omega-3 feeding, it is being used in many new supplements and grains. Related research has shown that higher-fat diets increase a horse’s requirement for the antioxidant vitamin E.
Here are a few practical tips for feeding fat:
• It may be easiest to use a commercially available high-fat feed.
• If adding fat separately:
• stick with vegetable fats, as animal fats or tallow is unpalatable to horses;
• Feed fat at no more than 20% of diet on a dry matter basis (2 cups of oil per day for a 1,100 lb. horse).
• canola oil won’t solidify at cold (barn) temperatures, but corn oil will;
• add fat gradually—start with ¼ cup and increase to the desired amount over a 2-week period;
• increase the vitamin E of the diet in proportion to the amount of fat (add 200 to 250 international units [IU] per cup of added oil); this is available at health food stores.
• Get advice from your vet about feeding to manage a specific disease or condition.