A study to determine the clinical signs of gastrointestinal rupture during colic was done by researchers at the University of California, Davis, and results were presented by Diana Hassel, DVM, of UC Davis at the 2003 American Association of Equine Practitioners' convention. Results of the study could help veterinarians know what signs to look for to make a definitive diagnosis of intestinal rupture, thus allowing them to prevent prolonged suffering of the affected horse and additional expense to the horse owner, as euthanasia for a horse with a ruptured intestine is inevitable.

The medical records of 149 horses with gastrointestinal rupture admitted to the UC Davis veterinary teaching hospital from 1990 through 2002 were examined. Common clinical findings associated with acute intestinal rupture included depression, sweating, reluctance to walk, tachycardia (rapid heartbeat), fever, an increase in the concentration of red blood cells in the blood, an abnormally low number of white blood cells, abnormal mucous membranes, elevated peritoneal (abdominal cavity) fluid protein concentration, and abnormal peritoneal fluid color, said Hassel.

She said that four of those signs were key in determining colic severity–heart rate, peritoneal protein concentration, blood lactate concentration, and mucous membrane appearance. "Heart rate and mucous membrane color are important indicators of cardiovascular status, are signs of endotoxemia, and have prognostic value regarding subsequent survival," Hassel said.

She said that on physical exam, 47.8% of horses had an elevated temperature (above 101.5°F, or 38.6°C), 92% had an increased heart rate, 67.2% had rapid and shallow breathing, 69.7% had an increased capillary refill time (longer than two seconds), and 85.5% had abnormal mucous membrane color. In addition, 65.6% were "shocky" or "depressed" and 17.6% had severe pain. Hassel also reported that upon rectal examination, a gritty feeling was found on the connective tissue that lines the abdominal cavity or there was the palpable presence of free gas within the abdomen in 48.4% of those cases which underwent rectal examination