Help prevent colic by:

• Feed the essentials. Give your horse the diet it needs—mostly grass and hay. Concentrates (grains), in moderation, can help boost protein, energy, and fat, but they can easily lead to a starch overdose, triggering colic. If you’re using grain, it’s best to feed your horse two to four miniature meals (2-3 pounds of feed per 1,000 pound horse) that are spaced evenly throughout the day.
• Follow a strict feeding program. The microbalance in a horse’s gut is very sensitive. Maintain a regular and unchanging feeding program to help your horse stay in balance. If you decide to change your horse’s feeding program, slowly switch their food during the course of 10 days by mixing old rations with the new rations.
• Facilitate foraging. Don’t give your horse large scoops of feed, as they will likely eat it all right away, which can disrupt their natural foraging and digestive processes. Give them smaller, equal-sized portions of feed more frequently throughout the day to allow steady digestion.
• Minimize sand ingestion. When horses eat sand, it settles in their large intestine. This can lead to colic, diarrhea, or a sand impaction. The most effective way to prevent sand colic is to prevent the ingestion of sand. Never put your horse’s food on the bare ground. Place feed in a tub, in hay racks with catch pans, or on rubber mats or concrete slabs that can be swept clean of sand. Always keep horses away from bare spots without turf. If your pasture is stressed, feed the horses hay until turf is reestablished.
• Minimize parasites. Parasites can cause colic in a number of ways like burrowing into tissue linings and intestines, releasing gut irritants, and damaging organs by traveling through the bloodstream. To fight against parasites, work with your veterinarian to develop a strategic deworming plan for your horse and farm, maintain good husbandry practices, such as removing manure from paddocks at least twice a week, dragging pastures on hot, dry days, and composting manure.
• Get active. Horses that stand still in their stall all day are more prone to colic. The turnout lifestyle is recommended, preferably with some companions. This keeps your horse moving in a social environment.
• Maintain a healthy weight.  Overly fat horses may be more prone to colic.