A referred to the University of Pennsylvania, New Bolton Center, for evaluation of chronic weight loss. The donkey had a 3-week history of occasionally pawing and being mildly depressed.On initial examination, the donkey appeared slightly thin, weighing 174 kg (382 pounds). He was quiet, responsive, with a normal temperature and respiratory rate. The heart rate was moderately increased at 84 beats per minute. He had decreased gastrointestinal borborygmi and passed mucous-covered feces. Once placed in his stall, the donkey appeared mildly painful as he repeatedly flexed his neck, while backing up, and then he would lie in lateral recumbency. Subjectively, he appeared to be attempting to swallow or move a food bolus down the esophagus. A nasogastric tube was passed, without obstruction, into the stomach and no gastric reflux was obtained. Limited by his small size, rectal palpation was nonremarkable. Pain was not elicited on palpation of the cervical spine although he did appear more comfortable when his head was supported in a slightly extended position. Neurologic examination was nonremarkable. The repetitive neck movement was considered a manifestation of general discomfort. Hematologic abnormalities included increased glucose (240 mg/dl, reference range 72-1 14 mg/dl) and fibrinogen (533 mg/dl, reference range 150-375 mg/dl). The white blood cell count, packed cell volume, and serum total protein were within normal parameters. An increased y-glutamyltransferase (106 U/1, reference range 12-45 UA) was the only abnormality on the serum biochemical profile. Ketonuria and glucosuria were detected on urinalysis.Additional diagnostics performed included gastroscopy, abdominal ultrasonography, and abdominocentesis. During the first endoscopic examination of the stomach, the mucosa was not visualized due to food within the distal esophagus