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Stomach Ulcers: Nutritional Factors, Treatment and Prevention

STOMACH ULCERS: NUTRITIONAL FACTORS, TREATMENT AND PREVENTION Excerpt from Horse Nutrition, a My Horse University online course

While gastric ulcers can occur in the esophagus and small intestines, the stomach is the most common site of gastric ulcer formation in the adult horse. Stomach ulcers most often affect the squamous mucosal cells of the lesser curvature of the stomach. Extreme ulceration in the stomach can lead to perforation of the stomach lining, a condition that is almost always fatal. Many forms of stress are linked to stomach ulcer formation as well as certain feeding management practices. Adult horses with stomach ulcers may appear lethargic, have a poor appetite, exhibit mild colic symptoms, have diarrhea, lose weight, exhibit a nervous or grumpy attitude, and show a decline in performance. Often, horses don’t exhibit any obvious symptoms but may just be “off” or are not reaching their full potential.

Diagram of a stomach highlighting the squamous region and the margo plicatus

Stomach ulcers are most common in the squamous mucosa cells adjacent to the margo plictaus of the stomach in adult horses.

The following are considered possible precursors to stomach ulcers in equine:

Exercise: Moderate to intense exercise is believed to be a contributing factor to ulcer formation in performance horses. It is theorized that the gastric emptying associated with exercise may increase the stomach acidity, a precursor to gastric ulcer formation. In addition, exercise causes the acid content in the lower part of the stomach to splash upward and potentially damage the squamous portion of the stomach. Maintaining forage in the stomach may help reduce the acid content coming in contact with the upper stomach. In a study involving Thoroughbred horses, stomach ulcers were found in all horses actively racing and in 90% of the horses in training (Murray et al., 1996).

Thorougbreds racing

Exercise intensity is directly related to gastric ulcer formation.

Housing: Stalling horses is also a contributing factor to ulcer formation. In one study, horses brought in from pasture and stalled developed lesions in the squamous mucosa within 7 days of being stalled (Murray and Eichorn, 1996). Potentially, isolation from other horses or the disruption of continuous feeding may trigger ulcer formation.

Stalled horses have a higher frequency of gastric ulcers than horses housed on pasture.

Transportation: Transporting horses as little as four hours may also predispose some horses to gastric ulcer formation. Again, the effect of disruptive feeding or the stress of hauling may all be factors.

Horse being loaded into a trailer

Stress associated with transportation for as short as four hours has been an indicator of ulcer formation.

Medications: Prolonged use of corticosteroids or non-steroidal anti-inflammatory medications can predispose a horse to gastric ulcers.

Feeding management also plays an important role in stomach ulcer formation.

Meal feeding: The practice of meal feeding may contribute to ulcer formation if the horse waits for long periods (over 4-6 hours) between meals. During this time, the stomach lining is not buffered by food contents and saliva. As the stomach acidity increases (pH decreases) for several hours, the stomach lining may be adversely effected. In contrast, horses on pasture grazing continuously have a more constant stomach pH (greater than 4) and a much lower incidence of gastric ulcer formation.

Grazing throughout the day decreases the risk of ulcer formation in adult horses.

Feed composition: There is still room for discovery on how the feed makeup affects gastric ulcers. In general, feeds that increase the acidity in the stomach and the production of volatile fatty acids through fermentation in the stomach are believed to increase the risk of ulcer formation. However, research in this area needs to be expanded to determine what feeds may be more problematic.

Ulcers can be diagnosed by examining the stomach through an endoscope. In some cases where stomach ulcers are suspected, a positive response to treatment is used as a positive diagnosis. Treatment of stomach ulcers involves reducing the acidity in the stomach as well as eliminating stress and changing management practices to promote a healthy stomach environment. Horses are often prescribed omeprazole, an antisecretory drug that acts by decreasing acidic secretions in the horse’s stomach. Omeprazole can be administered daily by an oral paste. In addition, horses are given a break from exercise and travel, and the forage component of their diet is increased.

Management practices that may help in the prevention of stomach ulcers include:

  • Provide free choice forage in the form of hay or pasture

  • Reduce time spent in the stall

  • Provide opportunities for turnout and grazing as much as possible

  • Reduce the amount of grain in the diet

  • Feed small meals of grain frequently

References and Additional Resources

Murray, M.J. and E.S. Eichorn. 1996. Effect of intermittent feed deprivation, intermittent feed deprivation with ranitdine administration, and stall confinement with ad libitum access to hay on gastric ulceration in horses. Am. J. Vet. Res. 57:1599-1603.

Murray, M.J., G.F. Schusser, F.S. Pipers, and S.J. Gross. 1996. Factors associated with gastric lesions in Thoroughbred racehorses. Equine Vet. J. 20:368-374.

Williams, Carey. 2008. MHU/HQ Webcast: Equine Stress.


Williams, Carey. 2008. Are You “Stressing Out” Your Horse?

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