Validation and prognostic value of plasma lactate measurement in bovine respiratory disease

The purpose of this study was to evaluate the accuracy of a portable blood lactate analyser for bovine blood and to study the relevance of plasma lactate concentration in the prognosis of bovine pulmonary disorders. Measurements with the portable analyser were highly correlated (R = 0.94, P<0.0001) with the measurements of the reference method but significantly different (P<0.0001). The portable apparatus slightly overestimated plasma lactate concentration compared to the reference method (bias = + 0.412). Plasma lactate measurements on 109 calves suffering from acute bronchopneumonia showed increasing lactate concentrations with severity of the disease. A plasma lactate concentration higher than 3.6 mmol/L or 4 mmol/L, measured with the reference method and the portable analyser respectively, appeared to be a reliable prognostic indicator for mortality within 24 h. Consequently, this measurement could be very helpful to decrease economic losses in cases of bovine respiratory disease, by avoiding unnecessary treatment costs on cattle with poor prognosis.