Gastric Ulceration in Adult Horses
Dr. Melissa Mazan
As always, your veterinarian will take a thorough medical history. Remember that your veterinarian usually won't know at first that the problem is gastric ulceration – rather, she will be examining your horse because you have told her that your horse is showing one of the symptoms that are listed above. This means that your veterinarian is usually asking questions to figure out why your horse is showing intermittent signs of colic or isn't 'quite himself'. Your veterinarian will probably question you about your horse's work schedule, feeding schedule, and deworming schedule. If your horse has been colicky, your veterinarian will want to know how many times he has colicked, how long each bout lasted, how severe the signs of pain were, and what your horse was treated with.
Your veterinarian will always perform a good physical examination, including taking your horse's temperature, and listening to his heart and lungs with a stethoscope.
If your horse has been colicky, your veterinarian will extend the physical examination, and include palpation per rectum (a 'rectal'). When your veterinarian performs a rectal, she is looking for any abnormalities in the position, size, or consistency of the internal organs. She will be particularly alert for abnormalities that could explain intermittent colic, such as an enterolith (a stone that can form in the large intestines), or thickening of the bowel that might indicate inflammatory bowel disease. Your veterinarian may wish to pass a nasogastric tube to make sure that your horse doesn't have excessive fluid in his stomach.
Depending on the signs that your horse is showing, your veterinarian will pursue various diagnostic tests.
If your horse has lost weight or has chronic colic, your veterinarian will probably do a thorough oral examination to see if poor dentition is contributing to the problem. Your veterinarian will want to know how your horse's appetite has been, and will probably want to look at your hay, grain, and pasture. Your veterinarian will probably also perform a fecal float to determine if your horse is carrying a high parasite burden.
If your horse has been showing chronic signs – whether that be colic, poor performance, or weight loss – your veterinarian will probably want to do bloodwork. A complete blood count, or CBC, looks both for evidence of inflammation or infection, and for evidence of anemia. If your horse has a high white cell count, or a high fibrinogen level (this is a protein that is found in the blood in the presence of inflammation or infection), then your veterinarian might suspect an infectious or inflammatory process. If your horse has a low red blood cell count, then your veterinarian will diagnose anemia.
Anemia can have many causes: gastric ulceration can make horses anemic due to actual blood loss from the ulcerated areas. Anemia can contribute to poor performance by making your horse feel weak. The red blood cells carry oxygen, which is the body's ultimate fuel. If there aren't enough red blood cells to carry adequate amounts of oxygen, then your horse will start to feel as though he is 'out of gas' when he goes to exert himself.
Because horses have extremely long digestive systems (at least 72 feet of small bowel alone!), most veterinarians agree that there isn't much use in looking for traces of blood in the feces, or fecal occult blood.
If, after extensive examination, your veterinarian decides that the medical history and physical examination findings are very suggestive of gastric ulceration, the definitive way to diagnose gastric ulceration is with a very long endoscope, known as a gastroscope. This allows us to place a camera inside the horse's stomach, and thus get a close-up view of the stomach lining. The type of endoscope that is commonly used to look at a horse's upper airways simply won't do – it isn't long enough. In order to visualize the adult horses stomach, an endoscope that is at least 210 cm long is necessary. That translates to 6.9 feet! In order to obtain a good view of the stomach, it is important for the stomach to be empty. That's why your veterinarian will usually ask you to keep your horse from eating for 18-24 hours before the gastroscopic examination. Your horse will still be able to drink during this time.
Although most of the time, your horse will have to undergo gastroscopy at a hospital for specialists, more and more veterinarians in the field are purchasing the appropriate equipment to do so. The procedure will be the same either way.
In order to do a gastroscopic examination, your veterinarian must pass the scope through the nostrils, into the pharynx (area just before the esophagus, or swallowing tube), and then into the esophagus, and, finally, into the stomach. Although gastroscopy isn't painful to the horse, most horses do resent anything being passed through the nostrils. The anxiety can be diminished considerably by giving the horse a tranquilizer – usually xylazine or a combination of xylazine and another drug. Long 'scopes' with the ability to see all the way into the stomach are extremely expensive, and your veterinarian will be anxious to keep your horse from chewing on it in case it doubles up and goes back into the mouth (yes, this does happen!). For this reason, usually a short plastic tube (similar to, but much shorter than the tube that is used for deworming your horse), is first passed through the horse's nose and into the esophagus, and then the scope is passed through that shorter tube.
Gastroscopy itself doesn't take very long – only approximately 15-20 minutes. Because the stomach is a collapsible organ, it must often be pumped up with air during the examination so that every bit of the surface can be seen.
Typical findings include areas of the stomach that are eroded, thinning, bleeding, or have abnormal amounts of scar tissue.
After the gastroscopic examination is finished, all the air will be let out of your horse's stomach to avoid colic. Then, your horse will still be kept off any food until he seems to have fully woken from the tranquilizer.