Right displacement of the abomasum and abomasal volvulus in dairy cows: 458 cases (1980-1987).

Clinical and surgical findings in 458 dairy cows with right displacement of the abomasum or abomasal volvulus (AV) were analyzed to determine the association between these variables and the outcome (productive, salvaged, or terminal) of the affected cow. Heart rate at initial examination was higher in the salvaged and terminal groups of cows (P less than 0.0001) than in the productive group. The plasma Na+ concentration was lower in the salvaged and terminal groups of cows (P less than 0.0001) than in the productive group. The plasma C1- concentration was lower in the salvaged group of cows than in cows with either productive or terminal outcomes (P less than 0.0001). Anion gap was significantly higher (P less than 0.0001) in the salvaged and terminal groups than in cows classified as productive. On the basis of surgical findings, cattle with right displacement of the abomasum were more likely to survive than cows with AV. Cows that required fluid decompression of the abomasum via abomasotomy were less likely to survive than those in which gaseous decompression was performed. Cows with evidence of vascular compromise of the abomasal wall were less likely to survive than those with normal abomasal serosa. Preoperative heart rate and anion gap had positive correlations with the presence of abomasal necrosis, whereas temperature, venous blood pH, plasma bicarbonate, and base excess concentrations had negative correlations. Cows in terminal stages of AV were likely to have a mixed primary acid-base disturbance, consisting of metabolic alkalosis with superimposed metabolic acidosis. These findings were highly correlated with abomasal necrosis.