Traditional Horse Feeding Practices
Recently, equine nutrition research has revealed a link between traditional (grain-based) horse feeding programs and many health-related disorders in horses. Traditional horse feeding programs generally contain large amounts (over 6 lbs./day) of cereal grains (oats, corn, barley), poor-quality forages (less than 8 % protein and 0.8 Mcal digestible energy/lb), and salt, but not many other important vitamins and minerals. Also, many horse owners top-dress several different specific nutrient supplements like biotin, Vitamin E, and iron.

Unfortunately, these programs have led to a 'normal' state where horses are deficient in some nutrients and overfed others. And, horses fed these rations often suffer from disorders such as colic, founder, gastric ulcers and tying-up and have poor-quality hooves, skin and hair. In fact, data from surveys reveal that the main concerns of horse owners are colic, founder and poor hoof quality. This is because horses have digestive tracts that are designed to process good-quality grasses and hays, but do not do a good job of processing poor-quality hays or cereal grains.

Digestible Energy Requirements of Horses
Horses require between 14 and 32 Mcal of digestible energy (DE) per day, depending on the size, class and workload of the horse (Table 1). Horses are expected to consume about 1.5-3% of their body weight in feed per day. So, for example, an 1100 lb. horse can eat between 16.5 and 33 lbs. of feed per day. Since forages contain 0.6 to 1.0 Mcal DE /lb., a horse eating 25 lbs. of hay with a DE of 0.9 Mcal/lb. can easily consume enough hay in a day to provide 22.5 Mcal of DE. That much energy is enough for all but hard-working horses and lactating mares. In fact, many horses can get most of their required energy from good-quality forages alone.

Table 1. General Digestible Energy (DE) Requirements of Horses
adapted from NRC Nutrient Requirement of Horses, 1989

Digestible Energy Content of Horse Feeds
Horse feeds can be classified, according to their DE content, into four categories; hays, fermentable fibers, grains and fat supplements (Table 2). In cases where additional energy is needed beyond what forages provide, fermentable fibers and high-fat feeds can be used, so that less cereal grains are required. Cereal grains are the basis of many feeding programs because of tradition and because of very efficient marketing campaigns of feed manufacturers. Grains contain 15-40% more digestible energy (DE) per pound than hays (Table 2). However, their higher DE content is usually not necessary, since many horses can eat enough good-quality hay to meet a majority of their energy needs and fats can supply the rest of the needed energy.

Table 2. Digestible Energy Content of Horse Feeds
adapted from NRC Nutrient Requirement of Horses, 1989

New Forage-based Rations
Research has also shown that if we feed horses more like the grazing, fiber-fermenters they are, we can reduce the risks of many of the common digestive disorders. And, the equine digestive tract can digest and absorb more nutrients from forages when they are not fed with grains. It only makes sense that horses should be fed their natural feed as much as possible. Jet planes don't do well on gasoline fuel, and your diesel truck won't run on unleaded car fuel.

This means we must start with the forage, not with grains, when formulating rations. And, fortunately, we now have more choices of feeds available for horse rations. Instead of just forages and grains, we now also have fermentable fibers (beet pulp, soybean hulls) and high-fat supplements (vegetable oils and stabilized rice bran) at our disposal.

Newer feeding programs are based on good-quality forage. Ideally, forage should be analyzed for nutrient content. However, if you don't have a consistent source of forage, book values for energy, protein and other nutrients can be used. When selecting hay, avoid mature grass hays with less than 8% protein, which tend to be very high in undigestible fiber and low in energy. The best hays for horse rations are immature grasses with some legume content (10-40%). Alfalfa and other legume hays are too high in protein and calcium to be the only forage in most rations, even when their high DE content would be of benefit.

Regardless of the type of forage you feed, if it is of questionable quality, you should find better forage. Adding grain to poor-quality forage is like putting a band-aid on a broken arm. You have not fixed the original problem, so it will not get better. Remember, since all forages are deficient in some minerals and vitamins for horses, a complete, balanced vitamin/mineral supplement, including salt, should be provided.

In cases where more energy is needed than forages alone can provide, high-fat products and fermentable fibers should be included in the ration. Horses can digest and use up to 12% added fat in the total ration. Finally, horse rations should be finished with the inclusion of grains, only when needed (Table 3).

Table 3. Percentages of DE Provided Per Feed Category in Forage-Based Rations

Conclusion
In conclusion, traditional horse rations contain large amounts of cereal grains, which put horses at greater risk of colic, founder, tying-up and gastric ulcers. Most horse owners feeding traditional programs are very concerned about these digestive disorders. Forage-based programs can provide the nutrients required for optimum performance and reduce the risks of under-feeding, over-supplementing, and metabolic disorders associated with grain starch overload. The only requirement is that you turn your back on traditional feeding practices and start feeding your horse like a horse.