Fat is often considered a bad word when it comes to considering our own diets but lately there has been growing interest in the horse world about fat. We should remember that in the case of our own diets and that of horses, some fats are necessary and healthy.
There are many reasons to feed horses added fat. The questions are: what kind of fat and what fat sources should be used?
The best reason for using added fat is for an energy (calorie) source. The primary purpose for extra feeding is to provide energy for maintenance, performance, growth and reproduction. Horses can use fat as a calorie source efficiently. Fat also lowers the risk of colic and laminitis by reducing the amount of starch (carbohydrates) in the ration especially in the case of horses feed a high cereal diet such as performance horses. Cereals have a high starch content which can have a negative effect on the horses digestion system resulting in a cascade of events that may include colic, laminitis and death.
When horses eat a high starch feed equivalent to 0.5percent body weight per meal there is a risk of starch entering the cecum. This translates into 2kg per meal on a 500kg horse. Thus adding fat makes a ration safer and feed intake can be lowered because fat has more than double the calories than starch.
Other reasons for adding fat to a feed ration are to improve endurance, heat tolerance, hair coat and attitude. Horses on fat supplemented diets experience increased endurance because of a glycogen sparing effect. Glycogen is the fuel for muscular activity that is stored in the muscle cells. Horses that are on high fat diets conserve glycogen, which can help them finish a performance event stronger. This is particularly important in racing, eventing, cutting and other activities that require high performance over time.
Horses trained in hot, humid environments show improvement to heat tolerance because fat supplemented rations generate less heat as a by-product of digestion. A shiny hair coat is important to horse owners who are showing or selling horses. Higher fat levels, especially those that contain a balance of omega three and omega six fatty acids, are good choices for those in the show ring or sale ring business. Horse owners often report that horses that are fed lower-starch diets with added fat have a calmer attitude than those that are fed a conventional high starch and forage diet.
Corn oil, soy oil, rice bran and flax seed (linseed oil) are the most popular fat sources for horses. There are advantages and disadvantages of each.
Corn oil is palatable and digestible, but it does not have a favorable balance of omega three and omega six fatty acids compared to soy oil or flax seed. Soy oil may not be as palatable as corn oil, however.
Raw rice bran is unstable and becomes rancid quickly, especially in hot weather. This is due to the enzyme lipase, which is present naturally. Rice bran can be stabilized by heat treating, which deactivates the lipase. During storage, raw rice bran progresses rapidly to rancidity and palatability suffers unless it’s processed quickly. Rice bran also has low calcium and a high level of phosphorus. This inverted calcium to phosphorus ratio can be detrimental for both young and high performance horses.
Most livestock fitters know that flax seed and the linseed oil that it contains produce a shiny hair coat. It’s also known widely that flax seed contains a high proportion of omega three fatty acids to omega six fatty acids. The process of extrusion during feed manufacturing stabilizes rice bran and flax seed, increasing shelf life with resultant increases in palatability and digestibility.
Indiscriminate fat supplementation can create deficiencies of other nutrients. This is known as empty calories; where energy levels are adequate, but protein, lysine and mineral levels are not. Developmental bone problems can result which may precipitate injuries in young horses.
There also is a period of adjustment of about three to four weeks for horses to receive benefits from added fat. Any change in diet should be done gradually over seven to10 days to avoid the possibility of digestive upsets.
A balanced diet, tailored to the use and age of the horse, is the most important consideration. A trained nutritional consultant can make recommendations that will best fit your horse and the activity involved.