[The use of ultrasonography for diagnosing the cause of colic in cows. A review].

Ultrasonography is a very useful technique for diagnosing the cause of colic in cows. It allows visualisation of abnormal reticular contour and occasionally of abnormal contractility in cows with reticuloperitonitis. In right-displaced abomasum, the dilated abomasum can be detected between the right abdominal wall and the liver. Fluid ingesta are seen ventrally and a gas cap of varying size dorsally. Dilated loops of small intestines that are almost always static are the main diagnostic criterion for ileus of the small intestine, but the cause of the ileus can only rarely be determined. Cholestasis can almost always be diagnosed by imaging a dilated biliary system. With obstruction at the level of the hepatic portal, only the intrahepatic biliary ducts are dilated, while a dilatation of the entire biliary tract, including the gallbladder, occurs in the case of an obstruction near the duodenal papilla. Urinary tract diseases cause colic in cows when concrement or inflammatory products become lodged in a ureter. The importance of ultrasonography in the diagnosis of diseases causing colic in cows varies. For example, with colic attributable to ileus of the small intestines, cholestasis or urinary tract disease, ultrasonography is a very useful diagnostic tool. On the other hand, for diagnosis of left or right displacement of the abomasum or caecal dilatation, ultrasonography is generally not required, but it is helpful in difficult cases to confirm or rule out a tentative diagnosis and to avoid an unnecessary exploratory laparotomy.