Venous and arterial ammonia in dairy cows with fatty liver and hepatic failure

In the present study we aimed to compare the arterial and venous plasma ammonia in dairy cows with fatty liver and hepatic failure. 75 Holstein-Friesian dairy cows were used in the investigation. Clinical examinations revealed liver failure in 14 cows (group LF). Diagnosis of hepatic failure was based on the clinical signs of hepatic encephalopathy, including anorexia, depressed consciousness, ataxia, somnolence, and coma, and on venous plasma ammonia >35 mumol/l. The other cows were divided according to their liver triglyceride content (wet tissue) into the following groups: low triglycerides (LT) <30 mg/g (n = 24), medium triglycerides (NIT) 30-100 mg/g (n = 31), and high triglycerides (HT) >100 mg/g (n = 6). Both arterial and venous plasma ammonia levels were highest in cows with hepatic failure (93.0 +/- 44.9 and 70.4 +/- 34.1 mumol/l, respectively). We observed that arterial ammonia was significantly higher than venous ammonia (P < 0.01) only in the dairy cows suffering from liver failure, implying a higher informative value of arterial ammonia in detection of liver function damage in cattle demonstrating signs of hepatic encephalopathy.