Preventing Gastric Ulcers
Q. What is the best way to prevent gastric ulcers in horses? I know there are various treatments available for horses that have been diagnosed with ulcers, but can horse owners in general prevent ulcers, and what is the best method in that regard? My understanding is that I should offer my horse:

  1. Free access to grazing if possible;
  2. Free access to hay with little to no fasting, if stabled for long periods;
  3. Alfalfa/alfalfa chaff fed with hard feeds; and
  4. Minimal disruption to his routine.

Perhaps you can confirm or elaborate on these?

Emer Cooney, via e-mail

A. Gastric ulcers can affect upwards of two-thirds of all performance horses and can cause weight loss, colic, and poor performance. Ulcerogenic factors identified include low-forage diets, intense/increased exercise, high-concentrate diets, regular/prolonged transport, feeding at intervals, management/housing changes, water deprivation, weaning, moving to a new home, and prolonged stabling. Prevention is therefore key to keeping your horse healthy and at the top of his game. The most effective prevention strategy involves a comprehensive combination of feeding, management, and pharmacologic approaches.

By understanding the physiology of horses’ gastrointestinal systems, we can feed them in a manner that reduces their likelihood of developing gastrointestinal problems including gastric ulcers. Horses are by nature continuous grazers that eat coarse grasses 16 to 18 hours a day in natural settings. However, many performance horses have significantly restricted grazing access and often require additional caloric supplementation to meet their energy requirements.

This predisposes these horses to ulcer development. Feeding strategies veterinarians recommend to decrease ulcer incidence include allowing free access to or long periods of grazing; providing constant hay access during periods of confinement longer than six hours; using restrictor/slow feeders to promote “foraging” and saliva production; feeding frequent small grain concentrate meals; replacing simple carbohydrate calories with fats and fiber-based diets; offering alfalfa hay/cubes/pellets; and providing continual access to clean, fresh water. Of these feeding practices, maximizing consistent daytime fiber intake and providing free water access are the most important.

When used as part of a comprehensive approach, some oral supplements might be beneficial when administered longterm. Administration recommendations are directed at maximizing their effect (for example, when they are fed relative to known periods of gastric hyperacidity), but the scientific evidence of their efficacy is sparse, so ask manufacturers for published evidence before purchasing.

Minimizing stress relative to housing, common routines, and transport may also be beneficial. Horses housed permanently on pasture with light exercise are six times less likely to get ulcers than stalled, moderately exercising horses, and horses with constant access to forage are four times less likely to get ulcers.

Minimizing changes in routine and applying stereotypy-reducing strategies—particularly in young horses—may be beneficial, as these behaviors’ development is often associated with ulcers. Researchers have shown that installing mirrors in stalls and trailers can help reduce blood cortisol (stress hormone) levels and potentially lower ulcerogenesis.

Although these feeding and management changes can result in lowered ulcer incidences overall, these practices often cannot overcome the isolated, high-stress, ulcerogenic nature of showing/competing. Many horses in these circumstances benefit from pharmacologic acid reduction prior to and during competition. Owners can administer UlcerGard (omeprazole), the only FDA-approved and scientifically proven ulcer prevention medication in horses, as a once-a-day dose just prior to and during stressful events. Other unapproved medications (i.e., ranitidine) are used with varying success in treating ulcers—often combined with decreases in training/stress—but researchers have not extensively studied doses, dosing intervals, and length of administration for prevention.

The important thing to remember is that not all horses are the same, and they might respond differently to the recommended approaches. Consult your veterinarian when instituting comprehensive feeding, management, and medication programs to maximize your success and to help avoid any unforeseen complications.