Five Equine Nutrition Myths Debunked

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There are many time-honored and tried-and-true methods to properly feed horses, but unfortunately, there are just as many myths and fallacies that have made their way into common belief today. Kathleen Crandell, PhD, a nutritionist with Kentucky Equine Research, addresses five common nutritional myths.

Myth #1 Concentrates or grains should form the foundation of a horse's diet, and hay is secondary.

Horses evolved on grasslands; wide-open spaces that offered a variety of vegetation from which to pick and choose. As such, their digestive tracts are designed to break down forages and to derive energy from the digestion of those plants.

The energy needs of certain horses, particularly members of breeds known to have low metabolic rates, can be met by forage alone.

“Most horses will eat somewhere between 1.8-2.2% of body weight per day," explained Crandell. "Forage should make up the majority of that amount. The absolute minimum forage requirement for any horse is 1% of its body weight. Therefore, an 1,100-pound (500-kilogram) horse would require 11 pounds (5 kilograms) of forage daily. Only a few circumstances require such a minimal forage intake, so a more reasonable recommended forage minimum is 1.5% of body weight daily.”

 Certain classes of horses might consume more. Lactating mares, for example, may eat 3-5% of body weight at peak milk production. As the total amount fed by body weight increases, so should the percentage of that amount made up by forage. A general rule of thumb would be to feed at least 50% of the weight of the diet in forage.

Concentrates should not be neglected for those horses that require them. Selection of the right concentrate for the individual can be key to making effective use of forages and balancing the diet.

Myth #2 Alfalfa (lucerne) hay is best left for dairy cows, not horses.

Alfalfa (lucerne) hay is a useful forage in the management of horses, and in some parts of the world it is a staple feedstuff. The advantages of alfalfa hay are numerous: most horses like the flavor, so they are apt to clean up a serving; it is packed with energy; it has ulcer-calming properties; and it comes in convenient alternative forms such as cubes and pellets.

Crandell said, “Compared to grass hay, alfalfa hay is richer in energy, protein and certain minerals, mainly calcium. Specific classes of horses benefit from being fed alfalfa, including those with increased calorie needs such as youngsters, lactating mares, aged horses and some performance horses. Because of its palatability, it is usually fed to horses recuperating from illness or those that have a limited appetite.”

As with all hays, a considerable range of alfalfa quality exists. Most horses do not need the top-quality alfalfa grown for high-producing dairy cows, and they can reap the benefits just as well from an average-quality alfalfa.

Alfalfa may not be the right fit for every horse, but concerns of alfalfa being too rich for all horses are unfounded, as many horses require the nutrient boost this legume provides, remarked Crandell.

Myth #3 Corn is a heating feed and will keep my horse warm in the winter.

Although corn is a useful ingredient in horse feeds, it is fundamentally no different than other cereal grains, such as oats or barley. The energy source in all cereal grains is starch, and once starch is broken down and absorbed into the bloodstream, the body does not differentiate starch based on source.

There are, however, differences among cereal grains in the amount of starch they contain. “Corn is higher in starch than oats," explained Crandell. "Corn may be about 67-77% starch, whereas oats may be 34-54% starch. Corn is heavier, too, so that when the energy content of an equal volume is compared, corn will have about 30% more calories than oats. And, when an equal weight is fed, the difference in calories is around 15%. Thus, when feeding corn, horse owners might be offering more calories than they realize, which may account for the impression that it makes horses more excitable.”

Consuming corn does not noticeably increase body heat any more than consuming other cereal grains. The majority of internal heat produced by horses is due to fermentation of forages in the hindgut. If corn reaches the hindgut and gets fermented, the amount of heat it produces is minute in comparison with the fiber fermentation from forage. 

Ideally, corn fed to horses should be heat-treated (pelleted, steam-flaked, micronized, extruded) to improve digestion of starch in the small intestine to avoid fluctuations in the microorganism population in the cecum.

Myth #4 Protein is the root of all evils, and every precaution should be made to rid a diet of excessive protein.

Protein is a vital nutrient for all horses, and its functions in the body are numerous. Protein deficiency can be caused by a diet of poor-quality hay with little or no concentrate. Deficiency is characterized by muscle wasting, difficulty staying focused and a general lack of energy. Some protein-deficient horses have a distinct loss of muscling over the topline, with protruding backbone and hipbones.

“Protein is not an efficient energy source," said Crandell. "When given a choice, the body would rather use other nutrients for energy such as carbohydrates and fats."

In an energy-deficient diet, the body will break down muscle tissue to use the protein for energy to fuel the body.

Horses are adept at processing protein, so there is no need to worry about adversely affecting kidney function. Nitrogen is a byproduct of protein digestion, and it is filtered by the kidneys and excreted from the body. Because of excessive nitrogen secretion in the urine, a strong ammonia smell might accompany a high-protein diet. Many horses that consume high-protein diets will also drink more water than usual, which increases urination.

“On the growth front, there is no evidence that developmental orthopedic disease is brought about in young horses by too much protein,” commented Crandell. A balanced diet reviewed by an equine nutritionist will ensure that young horses are properly nourished for steady and safe growth.

Myth #5 Feeding rates on feedbag tags are exaggerated, and my horse is fine with just a handful of feed each day.

Manufacturers design feeding rates to reflect the level of fortification in the feed. Fortification is the amount of protein, minerals and vitamins added to a feed to make it nutritionally appropriate for the class of horse it's intended for. Giving just a handful of feed will supply few calories and few nutrients.

“If horses are not fed the minimum recommended amount per day, they will not get an adequate supply of nutrients," stressed Crandell. "For instance, suppose a horse requires 2 milligrams of selenium each day. The recommended feeding rate for a particular feed is 4 pounds (1.8 kilograms) daily, and this quantity supplies the required 2 milligrams of selenium. If only a pound (or half a kilogram) is fed, the horse will receive just one fourth of its selenium requirement per day.”

If a horse becomes obese by feeding the minimum requirements, it is possible to limit caloric intake and still supply vital nutrients by replacing the concentrate with a ration balancer pellet or a well-formulated vitamin/mineral supplement in conjunction with appropriate forage.

Separating fact from fiction is sometimes difficult when horsemanship folklore is passed from one generation to the next. When in doubt about feeding management, ask an equine nutritionist for clarification.