There has been a growing appreciation recently for how common gastric (stomach) ulcers are in trained horses and in the general horse population, and the huge impact that this has on the horse industry. The development and more widespread use of the 3-meter endoscope has allowed us a tool to visualize the inside of the horse’s stomach and has alerted us to how common the problem is. Excellent recent research has helped to explain the different ways that gastric ulcers are caused and shed some light on what we can do to prevent the problem.
Gastric ulcers are very common in the performance horse population. Endoscopic studies of horses in training have shown that up to 90% of horses stabled in a race barn have stomach ulcers. At least 60% of horses in other competitive disciplines have ulcers. The prevalence in horses that are not in training is lower but is still high. Gastric ulcers are also common in young horses, especially those that have other illness.
Clinical signs of ulcer disease
The classic signs of ulcer disease in the adult horse are poor appetite, decreased performance, attitude changes, poor body condition, rough hair coat, and low-grade or repeated colic episodes. In foals, the classic signs of gastric ulcers are colic, diarrhea, teeth grinding, salivation and poor body condition. Temperament and pain tolerance can determine whether or not an individual horse shows clinical signs. Some horses with mild lesions show obvious and “classic” clinical signs while others with more serious lesions may show very little sign of a problem.
Diagnosis of gastric ulcers
The definitive way to diagnose gastric ulcers is with the use of a 3-meter endoscope. These scopes have been used at veterinary schools for years, but are now becoming more common in progressive equine veterinary practices.
The procedure goes something like this: The horse is kept off feed for 12 hours prior to the exam. It is usually lightly sedated. The scope (which has a video camera at its tip) is passed through the nostril and into the stomach. The stomach lining is visualized on a television screen. Ulcers appear as erosions of varying size and depth in the surface lining. The severity of these lesions is recorded on a video tape, and this record serves as a baseline for studies performed during and after treatment.
We have a 3-meter endoscope in our practice and have found it to be a valuable diagnostic tool. It allows us to make a definite diagnosis of this common problem and to monitor the effectiveness of treatment. It also allows us to diagnose other problems of the stomach and esophagus, such as certain types of cancer.
Research is currently progressing on a blood test for equine ulcers that measures sucrose levels in the blood. As of the time of this writing, this test is not yet available. The standard diagnostic tool remains the 3-meter endoscope.
Understanding how equine gastric ulcers occur gives some insight into how to manage horses to prevent the problem.
-Horses, unlike humans, secrete stomach acid continuously and independent of a meal. The presence of food in the stomach buffers this acid and so helps protect the lining from damage.
-Horses, unlike humans, have an upper portion of the stomach that has an unprotected lining and is vulnerable to damage by acid. The lower portion is the acid-producing part and is more resistant to acid damage. Recent research has shown that when horses are exercised at a trot or gallop, the pressure in the abdomen (the space around the internal organs) increases. This raises the level of the “acid pool,” which normally lies down low in the more resistant portion of the stomach, to the more sensitive upper part. This favors the formation of ulcers in this area.
-There are several different and distinct ulcer “syndromes” in different classes of horses which affect either the upper or lower portion of the stomach, or both. The bacterial cause of ulcers that has been determined to be such an important causative factor in human gastric ulcers has not been found to date in horses.
-Nutrition plays an important role in determining how acidic the stomach fluid is. High grain diets cause more acidity than low grain diets. Alfalfa actually causes a lower acidity than grass hay.
-One of the most important points is that ulcer syndromes can be unapparent. Mild problems are often attributed to other causes.
Horses diagnosed with gastric ulcers can be treated and often make full recoveries. The most effective treatment for gastric ulcers in horses is the prescription drug Gastrogard (omeprazole). This is a specially formulated paste form of a drug developed to treat human ulcers. It acts by directly inhibiting acid production by the acid-producing cells in the stomach. It is highly effective but is also very expensive.
Other medications that have historically been used to treat gastric ulcers have been shown in general not to be as effective as Gastrogard. These medications act by a more indirect route. They include ranitidine (Zantac), cimetidine (Tagamet), and the ulcer coating agent sucralfate (Carafate). Antacid medications are marketed with great claims for success, but have been shown to be mostly ineffective at lowering acidity in the horse stomach at recommended doses.
Managing your horses to prevent gastric ulcer syndrome
-Awareness is the key to prevention. The more you know about the syndrome, the better you will be able to manage your horses to avoid it.
-Feed only as much high carbohydrate grain as is necessary for the intensity of training.
-Keep high bulk feed present for your horses. The less time a horse spends standing around with an empty stomach, the better.
-Consider the timing of feeding versus training. ”Don’t train on an empty stomach.”
-Be on the lookout for subtle signs and ready to change your management accordingly.
-Consult your equine veterinarian. He or she can help you to make the right diagnosis and management decisions.
[ Thal Equine ]