Intestinal obstruction in the horse. Physical signs and blood chemistry.

Physical signs and blood changes were studied in horses with artificially produced obstructions of the duodenum and the small colon and simulated volvulus of the ileum. Horses with obstruction of the duodenum had the most violent physical signs and the shortest survival time. Blood changes were an initial rise in pH followed by acidosis, hyperkalemia and a decrease in HCO3 minus, Na+ and C1 minus. Obstruction of the small colon resulted in mild physical signs. The blood parameters recorded were normal. Simulated volvulus resulted in continuous colic. Blood changes were acidosis and hyperkalemia with a continuous decrease in HCO3 minus and C1 minus levels.