Gastroscopy or Equine gastric ulcer syndrome (EGUS) is a common condition in the horse. It can affect both adults and foals and describes ulceration in the oesophagus, stomach and small intestine. The condition is common in many different horses and recent studies have shown that it can affect up to 50% of foals, 37% of leisure horse, 60% of competition horses (dressage, eventing, show jumping), and 90% of racehorses in training.
EGUS is classified according to which part of the digestive tract it affects and in the stomach it is divided into Equine Squamous Gastric Disease (ESGD) and Equine Glandular Gastric Disease (EGGD). ESGD occurs in the upper 1⁄2 of the stomach in an area lined by squamous epithelial cells. This area is designed primarily for mixing food when the stomach is full. It is not well equipped for resisting the effects of acid exposure as, under normal circumstances, the food would help to protect it.
EGGD occurs in the lower portion of the stomach. This area contains cells that produce gastric acid and is also lined by glands which secrete mucus and bicarbonate to neutralise the acidic contents of the stomach. Unlike the upper portion of the stomach, the glandular region is designed to withstand the acidic stomach contents.
These 2 types of ulceration can occur alone or as a mixed condition. When a diagnosis of gastric ulceration is made it should include a description of the severity and extent of ulceration in each of these 2 areas.
The primary cause of ESGD is prolonged exposure to gastric acid and a number of different factors such as stress, transportation, high grain diet, intermittent feeding, intense exercise, inappropriate management and concurrent illness can cause the disease. Causes of EGGD are far less clear currently but have some similarities with ESGD.