title: Evaluation of aspartate transaminase activity and beta-hydroxybutyrate concentration in blood as tests for prediction of left displaced abomasum in dairy cows.
abstract: 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.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  AST activity and BHB concentration in blood obtained during the first or second PP week might be useful as predictors of subsequent LDA diagnosis.
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, Ontario, Canada.
authors.forename: T
authors.initials: T
authors.lastname: Geishauser
authors.forename: K
authors.initials: K
authors.lastname: Leslie
authors.forename: T
authors.initials: T
authors.lastname: Duffield
authors.forename: V
authors.initials: V
authors.lastname: Edge
mesh_terms: D020155:3-Hydroxybutyric Acid; D000018:Abomasum; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood*; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology; D005260:Female; D006885:Hydroxybutyrates / Q000097:blood*; D016014:Linear Models; D016017:Odds Ratio; D049590:Postpartum Period / Q000097:blood; D011237:Predictive Value of Tests; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013272:Stomach Diseases / Q000097:blood / Q000175:diagnosis / Q000662:veterinary*
chemical_list: D006885:Hydroxybutyrates; D001219:Aspartate Aminotransferases; D020155:3-Hydroxybutyric Acid