Gravel obstruction in the abomasum or duodenum of two cows.

Two Holstein cows from dry lot dairies were evaluated because of clinical signs of depression, anorexia, and decreased milk production. Bilateral abdominal distention and decreased fecal output were found on physical examination. Results of serum biochemical analyses indicated that the cows had severe hypochloremic, hypokalemic metabolic alkalosis. On the basis of physical examination and laboratory findings, an obstruction of the abomasum or cranial portion of the small intestine was suspected in these cows and abdominal exploratory surgery was performed. A mass of gravel was found in the pyloric antrum of the abomasum of 1 cow and the descending duodenum of the other cow. The duodenal obstruction was removed by enterotomy, and the pyloric mass was manually reduced during surgery. The cows were treated with antibiotics and isotonic saline solution (NaCl) supplemented with potassium chloride and recovered quickly after surgery.