As nomadic grazing animals horses have evolved to rely of forage for the bulk of their daily dietary requirements. Although the living conditions of horses have changed dramatically since their domestication, their nutritional needs have remained much the same. High quality forage is still the most important part of a horse’s diet. Forages fall into two main groups: grasses and legumes.
Grasses include pasture, and a wide assortment of grass hays including: Bermuda grass, timothy, orchard grass, brome grass, orchard grass, fescue, prairie grass and twitch grass just to name a few of the many grasses that make excellent horse hays. Pasture is the ideal choice of forage for horses. A well established and properly maintained pasture will provide all the nutrients a mature horse needs. Nutritionally, grass hays are generally perfectly balanced for adult horses. Most contain 9-12% protein and have balanced calcium to phosphorus ratio. In addition, grass hays do not contain excess sugar or other nutrients that would encourage a horse to founder. Green pasture grass in the spring can cause foundering in horses that are at risk, and horses who have not been properly introduced to the pasture. Grass hays offer little to no risk of founder and can be fed free choice in order to maintain good gut motility. The only grass associated with problems in horses is certain species of fescue. Tall fescue across the US and Canada has become infested with a fungus that causes gestational problems in mares. There is inconclusive proof that entophyte (fungal) infested fescue may also cause problems in mature horses, and particularly in young growing horses. Horse owners and hay growers are encouraged to have their fescue grass tested and destroyed if it is infested. Infested fescue grass should not be fed to pregnant or lactating mares. Grass hay can be fed free choice, or at 1.5-2% of a horses body weight.
Legumes include alfalfa, clover and trefoil. Legumes are no longer recommended as an ideal food source for horses. They are generally extremely high in protein ranging from 12-18% or higher when an adult horse only needs about 10% protein in its feed. In addition, legumes have an extremely high calcium to phosphorous ratio. Ideal calcium to phosphorous ration is 1.5:1 to 2:1. While calcium should always exceed phosphorous, excessive levels of calcium can result in growth problems in younger foals and other miscellaneous health problems for older horses. Legume hays generally have a calcium to phosphorus ratio ranging from 5:1 to 8:1. The excess protein in legumes is converted to carbohydrates and thus to energy. Many horse owner find that horses on a legume diet tend to be ‘hot’, and when the excess energy is removed from their diet (by a change in feed) the horses become calmer. The benefit of legume hays is that they can be added as part of a horses overall diet to increase protein and nutritional content as more of a supplement than a complete forage source. This is especially helpful in the case of young growing horses that have higher protein requirements (12-14%) and pregnant or lactating mares. Horses should be fed nutrient rich legume hay as part of a diet that contains enough grass hay to balance out its high calcium and protein content.
A less known but increasingly popular source of forage, especially for older horses that are no longer able to eat traditional hays, is beet pulp. Beet pulp is a by product of the sugar beet processing industry. It is a highly palatable, low sugar feed that is moderately high in protein and generally has slightly inverted calcium to phosphorus ratio. It is most often fed soaked, and is extremely easy to chew and digest. It is high in digestible energy and generally needs to be fed at 1-2% of a horse’s body weight. Because of it’s inverted calcium to phosphorus ratio, it is best to combine beet pulp with a higher calcium feed such as a legume hay, or legume hay cube (which can also be soaked and made easier for older horses to eat).
Regardless of the form of forage you choose to feed your horse, make sure that it is high quality and healthy. Hays should be free of dust and mold. Beet pulp and hay cubes should be stored dry and fed promptly if dampened to avoid spoiling. If your horse is unable to hold weight on forage alone, a concentrate in the form of grain can be added to the help increase calories and digestible energy.
