Colic fits all varieties of abdominal distress our horses experience. The causes of gut pain range from the passing discomfort of excessive gas to life-threatening intestinal torsions. The majority of colics are mild, but they're still troublesome, causing horses to pace, paw and roll while their caretakers fret over their discomfort. In these cases, the digestive system rights itself, given a little time or minimal medical attention.
Major intestinal disruptions, including blockages, twists and ruptures, are usually fatal unless surgery to remove or repair the diseased area of gut succeeds. Each year, hundreds of horses die on the operating table or shortly after, due to the disease itself or to complications from it.
Researchers haven't found a magic serum to guarantee your horse a colic-free life, but their increased understanding of equine digestion has allowed them to identify many of the conditions that predispose horses to colic. Using this information as the basis for preventive action, horse owners can take control of the stabling, dietary and environmental conditions that influence equine digestion for better or worse. By adopting consistent, rational management practices and maintaining horses according to Nature's operating manual, you can minimize your horse's risks of digestive distress.
Steps to Feeding Right
Horses are designed to graze on an unvarying diet of fibrous, low-energy forages for 12 to 20 hours per day. Unfortunately, domesticated living usually challenges the horse's sensitive digestive tract with feedstuffs, feeding schedules and ration portions that are far outside the norm of the natural plan. One of the primary reasons horses colic is the disparity between what the digestive equipment is intended to process and what it actually gets. Start your anti-colic campaign by evaluating and, if necessary, revamping your feeding practices.
1. Feed your horse only what he needs.
When it comes to maintaining digestive health, the best thing your horse can put in his mouth is grass, a high-fiber, low-carbohydrate feed containing eight to 10 percent protein. The second-best horse feed is grass in its dried, stored form, otherwise called hay. The bulk delivered by a fibrous grass/hay diet is a key weapon in fighting the colic wars because consistent gut fill maintains a continuous level of digestive activity, free of feast-or-famine stresses. Additionally, horses usually chew hay twice as long as grain. The more they chew, the more saliva is generated and mixed in, which helps buffer the stomach against acids.
This near-perfect grass/hay diet may not provide sufficient energy and other nutrients for the daily demands placed on some horses. Enter concentrates, feeds that boost one or more of the tissue-building and fuel-supplying dietary components: protein, energy and fat. The grain mixes commonly fed to horses usually include some combination of corn, oats and barley in pelleted or sweet-feed form and coated with molasses to improve palatability. The simple carbohydrates provided by concentrates--sugars, starch and soluble fiber--are good horse fuel in moderation. But an excess of starches in a horse's ration can upset the gut's delicate bacterial balance.
The digestion and absorption of modest amounts of starch occur in the small intestine, then the ingesta enters the horse's cecum and large intestine where fibrous particles are broken down. If a glut of simple carbohydrates overwhelms the starch-converting enzymes available in the small intestine, the remaining undigested carbohydrates pass into the cecum and large intestine. Some microbes there prosper on the starch, producing a high level of lactic acid as they break it down. This lactic acid kills key microbial fiber digesters in the hindgut. The resulting by-product inflames the gut wall and opens the way for absorption of toxins into the bloodstream.
"Normally, during fiber fermentation, these microbes produce volatile fatty acid, which is good," says Stephen Duren, PhD, of the equine nutrition and conditioning consulting firm Kentucky Equine Research, Inc. "In this case, the bacteria are killed by their own end product."
To reduce the risk of intestinal distress, review your horse's diet and feeding schedule, particularly his grain intake. Do you feed him grain because his work demands it or simply because all the other horses in the barn get grain? If you have a few companion ponies or pensioners among a barn full of performance horses, for example, a handful of grain will keep the nonworkers content at mealtimes without placing undue strain on their digestion.
What is a justifiable reason for including grain in a ration, then? "Horses are made to eat grass and hay, and they supplement their food with a variety of plant material," says veterinarian Joyce Harman, DVM, MRCVS, of the Harmany Equine Clinic in Washington, Virginia. "The reason for adding grain is to make up the calorie difference. The goal is to feed to maintain good body weight." Depending upon the horse's age, level of activity, lactation status and innate metabolic rate, the additional grain required to maintain an ideal weight may range anywhere from one to possibly 15 pounds a day.
The generally accepted maximum for concentrates in a horse's diet is no more than half the total amount--by weight--of the ration fed. "If you've got a 1,000-pound horse consuming 30 pounds of feed, and he's eating 20 pounds of grain, then you're looking at a colic risk," says nutritionist Sarah Ralston, VMD, PhD, of New Jersey's Rutgers University.
When you feed grain, offer it in two- to four-pound mini-meals spaced evenly throughout the day. Mixing the grain with moistened, chopped hay or grass also prolongs the horse's intake and modulates the amount of starch entering the gut at any one time. Finally, oats are the safest of all the common horse grains because they are highest in fiber and contain the most digestible form of starch, making them the least likely to trigger a starch overdose.