Relationship between bronchoalveolar lavage fluid and plasma endotoxin activity in calves with bronchopneumonia

The aim of this study was to investigate the relationship between the endotoxin activity in plasma and that in bronchoalveolar lavage fluid (BALF) in bronchopneumonia. Thirty-three calves were included in this study (17 healthy calves and 16 calves with respiratory disease). In the calves with bronchopneumonia, the median endotoxin activity in plasma (0.437 EU/ml, P<0.001) and BALF (29.45 EU/ml, P<0.001) was significantly higher than in the control calves. Plasma endotoxin activity was significantly and positively correlated with that in BALF (r(2)=0.900, P<0.001). Based on the receiver operating characteristics curves, we propose a diagnostic cutoff point for plasma endotoxin activity (0.104 EU/ml, AUC=0.914, P<0.001, Se 81.3% and Sp 82.4%) for identification of bronchopneumonia in calves which could die within a week.