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Henderson County Horse Committee |
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NUTRIENT CONTENT AND PROBLEMS Dr. Doug Householder All horses require long-stemmed roughage in their daily diets. High quality roughage provides nutrients, satisfies a horses' urge to chew and helps maintain the activity and integrity of the digestive tract. Since roughage fulfills these most important functions, it serves as the foundation decision around which all other feeding decisions are made. Roughage can be provided to horses either in the form of pasture or hay with pasture being preferred. When pasture is not available and/or if horses require more intensive management, hay, (which is just processed dried forage), is normally fed in place of pasture. Hays basically are divided into two categories, grasses and legumes. With regard to energy, grass hays (i.e. coastal) generally range from .7-.8 Mcal DE/lb. while legumes hays (i.e. alfalfa) range from .8-1.0 Mcal of DE/lb. Practically, this means that grass hays cannot be used as the sole source of energy for horses, with high energy requirements (i.e. cutting horse) but is adequate for horses with lower energy requirements (i.e. mature idle horse). Legumes are higher in protein than grasses, legumes ranging from 12-16% CP (or higher) while grass hays generally range from 6-10% CP. Legumes and grasses differ little in their phosphorus content; however, legumes contain three to four times more calcium than do grass hays. It is obvious why legume hays are routinely used in feeding programs for horses with high energy, protein and mineral requirements. Hays that are green, leafy and fresh (not over 6 months old) will contain carotene which can be converted to Vitamin A by the horse. However, hays that are bleached, weathered, dark, or older than 6 months, will contain little carotene. Therefore the concentrate feed fed with this older type hay, must provide most if not all of the horse's Vitamin A requirements. Most hays are safe to feed to horses; however, certain species; and growing, baling and storing conditions; can cause problems for horses. For example, fescue hay is unpalatable regardless of when baled. While very rare, occasionally hybrid sorghum sudan hay will cause cystitis problems. Dallisgrass hay often contains a fungus that can cause incoordination problems in horses. Hay baled with too much moisture will mold as is evidenced by either white or black spots of mold or powdery dust accompanied by a musty odor. Rusted wires are a sign of moldy hay. The more mature forage is when baled, the lower its digestibility, due to a higher lignin content, and subsequently the slower its rate of passage. "Hay belly" in horses is often caused by poor quality hay, not too much hay. Alfalfa is the most popular legume hay for horses due to its sweet fragrance, palatability and high nutrient content. Myths about alfalfa are that alfalfa precipitates kidney problems, causes increased sweating and causes more digestive upsets than grass hays. Again remember alfalfa hay is high in protein content. When horses consume more protein than they require, they urinate more to rid themselves of the protein they don't need. Excess urination does not hurt a horse with healthy kidneys. What about excess body heat? The conversion of excess protein to energy produces a small amount of additional body heat; however, excess sweating in horses fed alfalfa is mainly due to increased fat deposition from increased energy intake. Horses abruptly provided large quantities of lush alfalfa will develop a loose stool, but this is temporary until the digestive tract adjusts to digesting rich hay. In short, alfalfa does not ruin kidneys and heat and, colic horses if it is fed properly. Of real concern in alfalfa hay; however, is the blister beetle problem. The scenario is that at certain times of the year blister beetles can be present in growing alfalfa and the beetles can be trapped up in the bales at baling time. When present in hay, blister beetles are difficult to detect. If ingested by horses, the beetle poison, called "cantharidin", blisters the lining of the gut severely, the pain often leading to death of the horse. Contrary to some hay grower's comments, beetles have been reported in alfalfa grown in virtually all alfalfa producing states within the U.S. When purchasing alfalfa, buy alfalfa 1) directly from alfalfa growers who perform a pre baling check on all fields for beetles and 2) purchase hay baled before mid June and after August, when beetles are not present. |