Preoperative and postoperative L-lactatemia assessment for the prognosis of right abomasal disorders in dairy cattle

Abstract

Background: Preoperative L-lactatemia and heart rate have been suggested as prognostic indicators of outcome for cows with right dilatation of the abomasum or volvulus (RDA/AV). However, postoperative L-lactatemia has not been assessed as a potential prognostic tool. Objectives: To determine the prognostic value of postoperative L-lactatemia (LAC2), duration of treatment (Dt), relative L-lactatemia difference (compared with preoperative L-lactatemia [LAC1]) ([LAC2 - LAC1]/LAC2) and change in L-lactate over time ([LAC2 - LAC1]/Dt) as compared to preoperative findings (LAC1 and heart rate [HR]) as prognostic factors in dairy cows with RDA/AV. Animals: A total of 41 dairy cows were included: 19 with AV and 22 with RDA; 11 cows had a negative outcome (NO) and 30 cows had a positive outcome (PO) based on telephone follow-up with owners 30 days after surgery. Methods: Prospective cohort study. Analysis was performed using logistic regression and comparison of area under the receiver operating characteristics curve (AUC) using nonparametric tests. Results: LAC1 > 1.4 mmol/L or LAC2 > 2.2 mmol/L had the same accuracy with sensitivity of 100% (95% CI, 75.1-100%) and specificity of 80% (95% CI, 61.4-92.3%) for predicting NO. The relative L-lactatemia difference ([LAC2 - LAC1]/LAC1) or lactate kinetics ([LAC2 - LAC1]/Dt) were not associated with prognosis. The AUC of the preoperative model (which included HR and lnLAC1) was 0.92 (95% CI, 0.83-1.0) and that of the postoperative model (including only lnLAC2) was 0.95 (95% CI, 0.88-1.0); these were not significantly different. Conclusions and Clinical Importance: Postoperative L-lactatemia is helpful to predict outcome in cows with RDA/AV. The short-term change in blood L-lactate is not a useful prognostic indicator, at least during the period of time spent on the farm for surgery and treatment.