Gastric Ulceration in Adult Horses
Dr. Melissa Mazan
If you've ever had gastric ulcers or even just bad heartburn, you can sympathize with your horse when he has one of the most common health problems of the stabled horse – gastric ulceration. We humans have the luxury of a quick trip to the drug store for our favorite heartburn remedy, and we can call our physicians for a more in-depth diagnosis of why we experience such agonizing gastrointestinal pain. But horses can only show us by indirect signs that they are in chronic, debilitating pain. How can you understand the signals that your horse is sending you, and understand why he is sending you those signals? Recurrent colic
Gastric ulceration in any species refers to an erosion, or sloughing, of one or multiple areas of the surface layer of the stomach. Gastric ulceration is common in horses – in various studies, from 70 percent to 100 percent of horses examined had endoscopic evidence of gastric ulceration. This, however, does not mean that all of these horses had clinical signs of gastric ulceration.
Unlike people, who can develop gastric ulcers in response to a bacterial infection, no infectious cause of gastric ulceration has been identified in horses. In fact, few specific causes of gastric ulceration have been clearly identified. However, most practitioners recognize that stress seems to precipitate gastric ulceration in foals; and infrequent feeds of low-roughage, high carbohydrate foods and a high level of training have been implicated in adult horses.
Unlike humans, horses secrete gastric acid continuously, whether they are eating or not. In the wild, horses spend the majority of their days continually eating small amounts of relatively poor quality, high roughage food. Continual acid secretion accommodates this natural lifestyle perfectly. When horses are fed large quantities of high quality food infrequently, their stomachs empty rapidly, essentially leaving the stomach with nothing to do.
The stomach has a variety of protectant factors against the effects of gastric acid, but when the stomach is empty, the horse's ability to withstand the effects of gastric acid can be overwhelmed. If gastric ulceration becomes severe, the erosions may begin to bleed. Horses can eventually become anemic and low in protein due to losses through the gastric ulcers.
The use of certain anti-inflammatory drugs (such as phenylbutazone ('Bute') or flunixin meglumine (Banamine™) can also induce gastric ulcers in horses.
What to Watch For
Decreased manure production
Poor body condition
Your veterinarian will take a thorough history to try to identify any risk factors that may have contributed to your horse developing gastric ulceration. In addition, the following may also be necessary:
A thorough physical examination. Horses that exhibit symptoms of feed refusal, colic after feeding, weight loss, and do not have a fever, are the usual suspects.
A work-up for colic. If your horse has been showing signs of colic, your veterinarian may choose to perform a work-up for colic, including passing a nasogastric tube and performing a rectal examination to look for signs of intestinal distention or displacement.
Blood tests. Your veterinarian may also choose to take blood tests to make sure that your horse is not anemic or suffering from kidney problems.
Gastroscopy. This is the only way to definitively diagnose gastric ulceration. Gastroscopy refers to the use of a specialized endoscope – a fiberoptic instrument – that essentially allows the use of a camera to visualize the interior of the stomach. Your veterinarian will look for areas of the stomach lining that have an abnormal appearance – this may range from outright areas of bleeding to areas of eroded or thinned tissue.
If your horse has gastric ulceration, your veterinarian will choose to treat with one of a variety of drugs that decrease the acidity of the stomach. He or she will be able to make dietary and training recommendations.
It is important to follow all the instructions given by your veterinarian concerning length and frequency of administration of drugs. Make sure that your horse actually consumes the medications recommended by your veterinarian; it won't help if medications are left in a little pile in the bottom of the feed tub. For some picky eaters, it may be necessary to mix the medication with molasses or applesauce, and syringe it into the mouth.
It is important to monitor your horse's appetite, manure production, and attitude. Most horses will require a high roughage diet and plenty of turnout for best resolution of gastric ulceration.
Horses that have constant access to turnout and roughage in the form of hay or pasture, and horses that are not in training, rarely develop gastric ulceration.
Probably, the best prevention for gastric ulceration is to mimic, as best as possible, the life of a horse at free range. This translates into frequent small meals, a preponderance of roughage in the diet, and plenty of turnout.