The technical definition of an ulcer means or wearing down in the lining of the oesophagus, stomach or small intestines. The deepness of the lesion, tells how severe the ulcer is. Stomach ulcers mostly occur in the non-glandular area of the stomach. Occasionally, ulcers can also occur in the glandular area of the stomach. Stomach ulcers occur in horses of almost every age and commonly found in foals and horses in strenuous exercise.
Stomach ulcers are widespread with studies indicating up to 90% of Standard bred and Thoroughbred horses who go through rigorous training suffer from ulcers. The clinical signs of stomach ulcers are not visible in most horses. The affected horses show the signs that include poor athletic performance, weight loss and colic. Horses also have a unthrifty appearance and mild diarrhea. In foals, suffering from ulcers teeth grinding and excessive salivation are common.
Stomach Ulcers are caused by the following:
Diet and feeding management – feeding high levels of concentrates, feed deprivation and changing types of feed.
Medications such as NSAID’s.
Unrelenting stress caused by training.
Changes to the bile Acid Reflux.
The horse’s hindgut is made up of the large intestine, comprised of the cecum and the colon. Unlike humans, horses are incapable of digesting fibre on their own. But in the hindgut of the horse, billions of bacteria and other micro-organisms ferment the structural carbohydrates that constitute fibre and convert them to Volatile Fatty Acids that the horse can digest. These acids are the primary source of energy for the horse.
Due to the presence of less fibre in their diet, and the presence of fed concentrates such as processed grain and pellets are the primary reasons for the hind gut ulcer. Due to the presence of the loose hay in the diet, to encourage chewing and salivation, the rapid ingestion of concentrates allows these to reach the hindgut undigested. Microorganisms in the cecum and colon transform a portion of these high-energy feeds and starches into lactic acid, which are the reason for the hind gut acidosis. This acidic environment shifts the equilibrium of normal microorganisms and pathogenic bacteria, which causes an inability to ferment forage into Volatile Fatty Acids and thus leads to hind gut ulceration.