Great Lakes Equine Wellness Center has a 3mm gastroscope capable of examining the esophagus, stomach and proximal duodenum. Equine gastric ulcers affect up to 90 percent of racehorses and 60 percent of show horses. Ulcers are the result of the erosion of the lining of the stomach due to a prolonged exposure to the normal acid in the stomach.

The only way to definitively diagnose ulcers is through gastroscopy, which involves placing an endoscope into the stomach and looking at its surface. To allow this, the stomach must be empty, so most horses are held off feed for six to 12 hours and not allowed to drink water for two to three hours. With light sedation, the endoscope is passed through the nostril and down the esophagus into the stomach. The light and camera on the end of the endoscope allows the veterinarian to observe the lining of the stomach.