EVALUATION OF LIVER-FUNCTION TESTS IN NEONATAL CALVES

Objective-To evaluate the efficacy of tests for hepatic disease in you ng calves. Design-Prospective case-control study. Animals-28 clinicall y normal carves and 47 carves with histologically proven hepatic disea se. Procedure-Liver function tests and serum activity of liver-derived enzymes were determined on 28 clinically normal calves at birth and a t 2 weeks of age. These values were compared with the results from 47 calves with hepatic disease verified by histologic examination. Upper limit of confidence interval was determined for the results on the cli nically normal calves, and Student's t-test was used to identify signi ficant differences in the data from calves of various age-groups. Resu lts-None of the results of the common tests for liver damage or functi on (measurement of bilirubin, gamma-glutamyltransferase, glutamate deh ydrogenase [GMD], alkaline phosphatase, L-lactate dehydrogenase, aspar tate transaminase, or alanine transaminase) were clinically useful whe n used alone for detection of hepatic disease in calves less than 6 we eks old. Sensitivity of gamma-glutamyltransferase, GMD, aspartate tran saminase, and alkaline phosphatase as indicators of hepatic disease in this population of calves was 0, 59, 80, and 9%, respectively. Direct bilirubin (sensitivity, 87%) was more sensitive than total bilirubin (sensitivity, 66%). Serum enzyme activity of most enzymes (P < 0.01), total bilirubin concentration (P < 0.001), and sulfobromophthalein sod ium clearance half-life were significantly higher (P < 0.001) in newbo rn carves than in 2-week-old calves. Clinical Implications-Clinical fi ndings that indicate hepatic disease in carves that are less than 6 we eks old could be confirmed by measurement of serum activity of GMD Or concentrations of total serum bile acids or direct bilirubin. Percutan eous liver biopsy may still be needed and may provide the most informa tion.