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Improving Intestinal Motility in HorsesBy Kentucky Equine Research Staff · March 9, 2017

Measuring 100 feet or more in the average mature horse, the equine gastrointestinal tract serves many functions, all neatly compartmentalized:

  • The mouth chops and grind feed and forage into manageable pieces;
  • The esophagus transports ingesta from the mouth to the stomach;
  • The stomach further breaks down ingesta into minute particles that pass into the small intestine;
  • Some types of nutrients in the feed, such as nonstructural or water-soluble carbohydrates, proteins, fats, vitamins, and minerals, are digested and absorbed in the small intestine;
  • The remainder of the feed, primarily structural carbohydrates or fiber, pass into the cecum and large intestine, where they are fermented to form volatile fatty acids, a primary source of energy for the horse.

Any alteration in the proper functioning of this system can quickly become life-threatening. A large variety of disorders can decrease the ability of the gastrointestinal muscles to contract appropriately, delaying the movement of ingesta. Decreased motility, or hypomotility, can occur in cases of equine grass sickness, gastroduodenal ulceration, colic (e.g., obstruction, impaction, excessive wall distention, strangulating obstruction), inflammation of various regions of the gastrointestinal tract such as peritonitis, duodenitis, proximal jejunitis, and colitis.

Drugs currently used in equine medicine to treat horses with hypomotility of the gastrointestinal tract are vast and varied, some more effective than others. Plus, many of the available drugs have important side effects to consider before administration.

One promotility agent used in human medicine, prucalopride, was recently examined by equine researchers. Prucalopride works by a completely different mechanism of action than other promotility agents currently approved for use in horses. Prucalopride activates a serotonin receptor called 5-HT4. In human patients, oral administration results in rapid absorption of the medication and reportedly helps motility disorders of the esophagus, stomach, and intestine.

Preliminary studies in horses* show that prucalopride appears to be safe and can effectively increase contractility of the duodenum, cecum, and colon following oral administration. Further research must confirm these findings; however, the researchers stated, “Prucalopride may be a useful adjunct to the therapeutic armamentary for treating hypomotile upper gut conditions of horses.”

According to Kathleen Crandell, Ph.D., a nutritionist for Kentucky Equine Research (KER), prevention of gastrointestinal disorders through proper nutrition and supplementation is always the best remedy.

“KER’s dietary supplement RiteTrac supports total digestive tract health. The fast-acting antacids and coating agents quickly neutralize excessive gastric acid and contains EquiShure, a time-released hindgut buffer to minimize hindgut acidosis. Such a product might be particularly beneficial for horses prone to hypomotility disorders, colic, gastric ulcers, or hindgut acidosis,” recommended Crandell. In Australia, look for these proven products.

*Laus, F., M. Fratini, E. Paggi, et al. 2017. Effects of single-dose prucalopride on intestinal hypomotility in horses: preliminary observations. Scientific Reports. 7:41526.