Page 749 - The Veterinary Care of the Horse

to 16 hours a day, the acidity is reduced by the forage and also by bicarbonate in the saliva. If

horses are stabled, however, and fed high-concentrate diets with only limited access to hay
VetBooks.ir and grazing, the acidity in the stomach increases. Any period without forage intake, whether
due to management practices or illness leads to increased gastric acidity and risk of ulcers.

EXERCISE

Training and racing at fast speeds is associated with a high incidence of gastric ulceration.
This may be due in part to the various stresses associated with training. Another

consideration is that the high abdominal pressures that occur in the galloping horse may be
sufficient to squeeze the acid stomach contents into the upper, acid-sensitive non-glandular

portion of the stomach. Intensive exercise may have a number of adverse effects on gastric
physiology, e.g. by reducing blood flow to the stomach, increasing the acid secretion or
delaying emptying of the stomach contents into the duodenum. Training more than 4–5 days

a week has been shown to increase the risk of EGGD in racehorses.

STRESS

Stress factors that may play a part in the development of gastric ulcers include:

• Disruption to the horse’s normal routine, e.g. change of environment, companion, handler

or rider
• Travelling

• Intensive exercise

• Insufficient time in the field

• Injury
• Other illness

• Parasitism, e.g. Gasterophilus (bot) larvae

• Weaning

A combination of these predisposing factors can affect the gastric mucosa, allowing the acid

and enzymes to erode the stomach wall and form ulcers. The temperament of the horse is an
influential factor.

NON-STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS)

In some horses, as in humans, administration of non-steroidal anti-inflammatory drugs, e.g.
phenylbutazone and flunixin meglumine in high doses, is considered to increase the risk of

gastric ulceration, particularly in the glandular part of the stomach. They do this by