Equine U: Equine Nutrition 101


    The foundation for caring for your horse and keeping him healthy begins with what he eats. Nutrition is something every horse owner should take some time to learn about, since the digestive tract of a horse is very different from our own and requires some understanding.

    Horses are designed to eat large amounts of fiber-rich plant matter all day long. While this wouldn’t provide enough calories for a human, horses send their food relatively quickly through the stomach and small intestine to the large intestine, where the real work begins. In the large intestine, millions of microbes go to work consuming the plant fiber that can’t be digested by enzymes naturally produced by mammals. The products of the microbes’ activity are easily absorbed and converted to energy and even protein by the horse’s body. Feeding for the health of the horse and the microbes can help reduce the incidence of colic and other digestive problems.

    Frequent Feedings
    A horse’s digestive health is dependent on frequent meals to keep the stomach and hindgut busy throughout the day. An empty stomach is a major cause of ulcers in horses, which are very common. By feeding him three to four times a day (or more) instead of just one or two, you will keep his stomach full most of the time, and give the microbes in his large intestine constant work to do, which keeps his gut healthy.

    Feeding small meals is especially important when it comes to grain, which is consumed much faster than hay. A large amount will pass through the small intestine without being fully broken down, leaking starches and sugars to the large intestine. This overwhelms the microbes and creates toxic byproducts that can lead to colic or laminitis (founder).

    Hay and Pasture
    The simplest way to feed horses is by providing lots of high-quality forage, which includes either hay or pasture grass. Forage usually provides 100 percent of a horse’s calorie and protein requirements if he is only worked lightly. The time spent consuming forage is good for the horse, keeping him busy and less likely to develop vices such as cribbing, wood chewing, weaving or stall-walking.

    There are two types of forage: grass and legumes. Orchardgrass and timothy are two grasses often baled for hay. Clover and alfalfa are the two most common legumes fed to horses in hay or pasture form. Legumes are significantly higher in protein and calcium. However, horses do not need large amounts of protein unless they are lactating or young and growing quickly (particularly weanlings).

    Hay that is baled during early plant maturity will be richer in calories and lower in fiber than late-maturity cuttings. The more mature the plant, the woodier the stems become, which is also less palatable for horses and results in more wastage. Ask your hay grower if the hay is early or late maturity. Overweight horses may benefit from a higher-fiber hay, whereas a “hard keeper” needs a more calorie-dense, tasty meal.

    Care should be taken with any horse when introducing him to lush pasture. This should never be done suddenly or all at once. Instead, allow gradually increased periods of grazing time each day to allow the horse’s system to get used to the rich nutrients without developing colic or laminitis.

    The number of horses a pasture can support is usually no more than one per acre, and in arid conditions, this number can be as low as one horse per two to four acres (or more). Regular mowing should be a part of pasture care, as it controls weeds and keeps plants in an earlier maturity stage. As plants become mature and reach seed head, they contain less nutrients and are less palatable to horses. During the winter or in overgrazed pastures, hay (and possibly grain) must be provided to meet energy and other nutrient demands.

    Further Reading
    All About Hay
    Choosing Good Hay

    Although mixed grains are readily available in large quantities at most feed stores, they should never account for more than 25 to 50 percent of the diet (by weight). Be mindful that a scoop of one feed may not be equal in weight to a scoop of another, and always feed grain in small portions (less than 6 pounds). Grain mixtures specifically formulated for horses have the benefit of meeting a horse’s vitamin and mineral requirements. If a horse needs more calories even when consuming grain, other options are to upgrade forage quality or add fat to the diet.

    Further Reading
    Feed Labels: Analyzing the Nutritional Guarantee

    Overweight or Underweight?
    Most horses in light-to-average work can meet caloric and nutrient requirements solely from high-quality forage (hay or pasture) plus a trace mineral salt block. A general rule with hay is to feed 1.5 to 2.0 percent of body weight (purchasing a hay scale and body weight tape are good investments). For an average 1,000 pound horse, this equates to 15 to 20 pounds of hay per day.

    The easiest way to tell whether your horse is too fat, too thin, or just right is to assess his body condition with the commonly-used scoring system ranging from 1 (extremely emaciated) to 9 (extremely obese). Anywhere from a 4 to a 7 is considered an acceptable score for most horses. Generally ribs should be easy to feel, but not easy to see. If the horse is carrying a winter coat, use your hands to determine where fleshy or bony areas exist.

    If your horse appears too thin, you will want to increase his calorie consumption until he reaches a suitable weight. Particularly in cold weather and when exposed to wind and rain, horses must burn more calories to keep warm. Hay is the ideal winter feed, since digestion from microbe fermentation provides a “free” heat source when compared to grain, which does not.

    If a horse is overweight, high-calorie feeds should be removed from the diet, but roughage can still be fed free-choice. You may want to switch to more mature hay or one containing mostly grass if he has been gaining weight on alfalfa or alfalfa-grass mixture. Horses that gain excessive weight grazing may need to be moved to dry lots and fed carefully weighed amounts of hay, or wear grazing muzzles to lessen the amount of lush grass they can eat.

    Exercise is a much healthier way to help your horse shed pounds than starvation or skipping meals, which leads to ulcers, behavioral problems, and metabolic disorders.

    Further Reading
    Balancing Your Horse’s Diet
    Meeting Your Horse’s Nutritional Needs

    The importance of clean drinking water cannot be overlooked. In hot weather, water intake may quadruple. In winter, heaters may be needed in buckets or outdoor automatic waterers to ensure that horses keep drinking. Waterers should be checked every day, and buckets washed and refilled, to be certain that horses have free access to clean water at all times.

    Vitamins, Minerals and Supplements
    While many supplements exist on the feed store shelves, you must know what you’re putting in before adding it. Feeding vitamins and minerals beyond the horse’s requirement doesn’t usually help, and may be toxic in large amounts. Most commercial grains contain a full spectrum of balanced vitamins and minerals, so no other supplementation is necessary.

    Sodium (in the form of salt) is a very important mineral for horses, but the requirement can usually be met by providing free access to a salt block.

    Further Reading
    HorseChannel’s Guide to Supplements

    With a basic understanding of how your horse’s digestive system works and what his needs are, you should be able to walk into the feed store with confidence. When in doubt, always consult your veterinarian or an equine nutritionist. Finally, keep an eye on the horse himself, and you’ll know if your feed program is working or is ready for revision.

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    Holly Caccamise, Editor
    Holly Caccamise has been with Horse Illustrated and Young Rider magazines since 2007, and in 2019, she became Editor in Chief of both titles. Caccamise has a master's degree in...


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