title: Association between β-hydroxybutyrate concentration at surgery for correction of left-displaced abomasum in dairy cows and removal from the herd after surgery.
abstract: OBJECTIVE
  To estimate the sensitivity, specificity, likelihood ratios, and predictive values of blood β-hydroxybutyrate (BHB) concentrations in dairy cows immediately prior to surgical correction of left-displaced abomasum (LDA) for determining associations between BHB concentration and removal from the herd ≤ 30 days after surgery and to evaluate postsurgical risk of removal for cows with the BHB concentration that had highest sensitivity and specificity for predicting this outcome.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  136 dairy cows with LDA diagnosed between 5 and 30 days in lactation (ie, days in milk).
  
  
  METHODS
  Blood BHB concentration was measured immediately prior to surgery. All cows underwent surgical correction of LDA while standing. Follow-up information was obtained ≥ 30 days after surgery. Receiver operating characteristic curves were used to estimate a critical threshold value for BHB concentration that was associated with removal from the herd, and this value was used in Poisson regression to estimate risk ratio for the same outcome.
  
  
  RESULTS
  While controlling for parity in the model, cows with a BHB concentration < 1.2 mmol/L at the time of LDA surgery were 2.5 times as likely (95% confidence interval, 1.3 to 5.0) to be removed from the herd ≤ 30 days after surgery, compared with cows that had a BHB concentration ≥ 1.2 mmol/L.
  
  
  CONCLUSIONS
  Results indicated that blood BHB concentration in dairy cows undergoing surgical correction of LDA may potentially be a useful prognostic indicator for the likelihood of removal from the herd ≤ 30 days after surgery. Further research is needed to evaluate other risk factors that may be associated with this outcome.
authors.affiliation: White Oak Veterinary Clinic, PC, 7631 Glades Pike, Berlin, PA 15530.
authors.forename: William S
authors.initials: WS
authors.lastname: Croushore
authors.forename: Paula A
authors.initials: PA
authors.lastname: Ospina
authors.forename: David C
authors.initials: DC
authors.lastname: Welch
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Zawisza
authors.forename: Daryl V
authors.initials: DV
authors.lastname: Nydam
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000097:blood*; D000018:Abomasum / Q000601:surgery*; D000822:Animal Husbandry; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood*; D015331:Cohort Studies; D003612:Dairying; D005260:Female; D007774:Lactation; D011379:Prognosis; D012307:Risk Factors; D013272:Stomach Diseases / Q000601:surgery / Q000662:veterinary*
chemical_list: D020155:3-Hydroxybutyric Acid