Evaluation of aspartate transaminase activity and beta-hydroxybutyrate concentration in blood as tests for prediction of left displaced abomasum in dairy cows.

OBJECTIVE: To evaluate aspartate transaminase (AST) activity and beta-hydroxybutyrate (BHB) concentration in blood obtained during the first or second postpartum (PP) week as tests for prediction of subsequent left displaced abomasum (LDA) diagnosis in dairy cows. ANIMALS: 36 cows with LDA tested at a mean 3 PP days, which was 7 to 22 days prior to LDA diagnosis (25, 75% quantiles), and 28 cows with LDA tested at 10 PP days, which was 5 to 18 days prior to LDA diagnosis, were matched to 3 controls per case by herd and calving date. Data were available from a large field study. PROCEDURE: Odds ratio, sensitivity, specificity, and likelihood ratio were determined for various AST and BHB cutoff values.
RESULTS: AST, using cutoff values between 100 and 180 U/L, and BHB, using cutoff values between 1,000 and 1,600 mumol/L, were significantly associated with subsequent LDA diagnosis. When cutoff values were increased, odds ratio and likelihood ratio increased; however, sensitivity decreased and specificity increased. CONCLUSION AND CLINICAL RELEVANCE: AST activity and BHB concentration in blood obtained during the first or second PP week might be useful as predictors of subsequent LDA diagnosis.