Minerals for Horses are needed by the horse's body for various purposes, ranging from serving as components of the horses skeletal system to maintaining nerve conductivity, muscle contraction and electrolyte balance. Calcium and phosphorus comprise about 70% of the mineral content of the horse's body. Therefore these minerals need to be supplied to the horse in the greatest amount and are of most concern in formulating horse rations. Horses are more likely to suffer from a lack of calcium and phosphorus than from lack of any other mineral. Proper levels and ratios (calcium:phosphorus) of these 2 minerals are very important to normal development of bone, because if inadequate levels or improper ratios are supplied structural deformities may result. Ideally calcium and phosphorus should be fed at a 1.2-1.6: 1 ratio. However, ratios as high as 6:1 have been fed to mature horses and ratios of 3:1 have been fed to growing horses with no detrimental effects. Never feed an inverted calcium:phosphorus ratio because it may harm the horse.
Always provide salt to the horse free-choice. Salt is most commonly given by providing a trace mineralized salt block free choice. In addition to the block, include a trace mineralized premix in the ration at 1/2% of the concentrate mix. Salt is composed of sodium and chloride which are important in maintaining electrolyte and acid base balance. Over consumption of salt is usually not a problem if free choice, nonsaline water is available. The practice of providing trace mineral salt will not only meet the horse's sodium and chloride requirements but will also meet its needs for other trace minerals.
Copper and zinc have been implicated in metabolic bone disease. Although their exact role is not clearly
understood, it is recommended to include copper in the concentrate at 30-50 ppm and zinc at 80-120 ppm.
Selenium is also a trace mineral required by the horse. Most naturally occurring feedstuff will have enough selenium to meet the horse's needs. (Selenium is extremely toxic when fed in quantities above recommended levels.) However, Kentucky is a selenium marginal state and as such most commercial feeds will contain selenium at .1 ppm. Therefore, do not top-dress it as a mineral supplement.
Vitamins A, D and E are the most common vitamins added to horse diets. Although B complex vitamins may not be commonly supplemented, including them in performance horse diets may be necessary. It is a common practice to fortify diets with a vitamin premix like the one Vitamin A is the vitamin most likely to be marginal in
most horse diets. The natural source of Vitamin A is betacarotene which occurs in green forages and properly cured hays. As long as the hay source has a green color and is leafy, then it will probably be more than adequate to meet the horse's Vitamin A requirement. Vitamin A functions in the maintenance of epithelial integrity, normal bone metabolism and is very important for night vision. Therefore, a deficiency in Vitamin A may result in night blindness, upper respiratory infection, brittle bones and possibly many other deficiencies. One reason to supplement Vitamin A is that horses are not very efficient in converting beta-carotene to
active Vitamin A.
Vitamin D is very important in the normal absorption and utilization of calcium and phosphorus. It also functions in the absorption of several minerals for bone deposition. Vitamin D is converted from precursors through a series of reactions in the skin stimulated by sunlight. Rickets in young horses and osteomalacia in older horses are the two most common symptoms of Vitamin D deficiency. Giving large doses of Vitamin D should be avoided as toxicity may occur resulting in calcification of soft tissue. Natural sources of Vitamin D occur in sun-cured hay and cod liver oil.
Vitamin E is found in ample quantities in most natural feedstuffs to meet the horse's requirement. Roughages,
cereal grains and especially cereal germ oils are high in Vitamin E, particularly wheat germ oil. Vitamin E has been implicated in many physiological functions in the horse body. It maintains membrane stability and red blood cell integrity. Selenium and Vitamin E interactions may play a role in treating and preventing “tying up,” and possibly in assuring normal reproduction.
It is believed that the microflora in the cecum will synthesize adequate amounts of B vitamins for absorption
to meet the horse's requirement. Many of the B vitamins function as coenzymes in energy pathways and it is questionable whether adequate amounts of B vitamins are synthesized by the horse to meet the needs of young, rapidly growing horses and horses at high work levels.
Remember that horses need long stem roughage in their diet for normal digestive function. Horses fed hay or those on pasture are more able to maintain gastro-intestinal tract normalcy, experience less colic and are less prone to developing annoying stable vices when compared to horses not receiving a long stem roughage source. Feed horses a hay that is bright colored, leafy, harvested in an early stage of maturity and free from mold or foreign matter. Common hays fed include alfalfa, timothy, clover, orchardgrass, brome-grass, prairie hay and bermuda.
You can also combine these hays for feed. When timothy and alfalfa are used together, alfalfa will usually be fed as a nutrient source and timothy as the roughage source. Use pastures to their utmost in a feeding program. Many classes of horses can meet their nutrient requirements on pasture alone, if the pasture is managed and stocked properly. Mature, idle horses, barren mares and mares in the first 2 trimesters of gestation on well managed pasture should require little or no supplementation. Remember that horses are individuals and should be managed as such. By knowing the nutrients they need and their function, you will find the art of feeding horses much easier and simpler.