Horses by nature are grazing animals. This means that they naturally need forages as the mainstay of a healthy diet. Hay provides a perfect replacement for the grasses they may not have access to as stabled animals turned out in dirt paddocks or pastures that lack sufficient forage to maintain health.
The average mature horse generally consumes 2 to 2.5 percent of its body weight in feed each day. Ideally, at least half of that should come from hay or pasture for optimum growth and development.
Mature horses that are not working or being used as breeding animals can actually thrive on high-quality forages alone. However, those horses that are still growing, that are being used as breeding animals, or that are in athletic training programs usually require supplementation with grains and other concentrates to maintain optimum health.
Hay provides many nutrients. The exact nutrient value of any given sample of hay can only be determined through forage testing, which is available through your local extension office. Generally, hay is high in calcium and low in phosphorus. It often contains high levels of potassium and vitamins A, E, and K. If it is dried in the sun rather than via chemicals, it likely will have high levels of vitamin D. The protein content of hay varies almost too much to generalize. But some guidelines include the following: legume hays (such as alfalfa or clover) can provide as much as 20 percent crude protein; grass hays (such as timothy or bromegrass) average about 10 to 15 percent protein and can dip as low as 3 percent.
Production Methods and Protein Content
Hay production techniques largely determine protein content. Hay cut early has a higher protein content. Hay cut much past midbloom stage may offer inadequate levels of protein, so the horse must be fed protein supplements to maintain optimum health.
High-quality hay is the result of careful hay production methods. It is cut early and should appear leafy (if legume) or feel soft in texture (if grassy hay), and be free of mold, dust, weeds, and other undesirable matter. Its smell should be appealing, not musty. If you are unfamiliar with hay selection, it would be worth your time to visit with your local extension agent or agricultural education instructor to learn more.
Types of Hay
There are two main types of hay with which most horsemen are familiar. These can be fed singularly or in a mix known simply as "mixed hay."
A family of plants having root nodules that produce nitrogen; they also have stems that leaf out into leaflets as is typical of the clover plant. Legumes are the highest in protein of all hays; averages show they can contain two to three times the amount found in grass hays. They also are higher in calcium, beta-carotene, and vitamin E.
Some believe legumes are also the most palatable of grass hays. This is why many horsemen prefer alfalfa or alfalfa mix hays over grass hay for growing, breeding, or highly athletic horses. Still, their high protein content makes legumes potentially dangerous to feed to mature, idle horses. Be careful, and become knowledgeable about horse nutrition.
Alfalfa is the most commonly known and grown legume. Some estimates list alfalfa or alfalfa-mix as constituting more than half of all hay grown in the United States. Other legumes include clovers, bird's-foot trefoil, and lespedeza.
Grass hays come in a much wider variety than legumes, since numerous types of grass are native to each region of the United States. Grass plants grow with tall stalks and long, slender leaves that often wrap around the stalk, rather than branching out the way legumes do. This makes grass hay dry faster; as a result, mold is less of a problem. Grasses also don't have problems with blister beetles like alfalfa can. This means grass hay is often a better choice for horses with compromised breathing. Their lower protein and nutrient density actually makes grass hay more desirable as a feed for mature and idle horses that aren't used for breeding.
There are far too many varieties of grass hay to include here. But a few of the most common ones fed to horses are timothy, Bermuda grass, bromegrass, bluegrass, fescue, ryegrass, and orchard grass. Timothy is perhaps the most common and widely grown since it is easy to grow in a variety of soils and cold climates.
A combination of legume and grass varieties into one crop. Mixed hay provides the best of both types of hay. It is more appealing to horses because they often prefer the smaller leaves of legumes. The mix of nutrient values (high-protein legume and lower protein grass hay) makes this hay the choice of many professional stable managers because one type of hay can be fed to all types of horses.
See also: Feeding and nutrition; Feeding equipment