Lung auscultation and rectal temperature as a predictor of lung lesions and bovine respiratory disease treatment outcome in feedyard cattle

Abstract

Studies were conducted to examine the use of lung auscultation to predict bovine respiratory disease (BRD) case outcome in feeder cattle. In the first study, lung sounds were obtained and lung auscultation scores (LAS) were assigned by trained personnel. Antemortem physical examination and LAS were correlated with lung pathology and lung lesion scores at harvest. A field study was then conducted to determine LAS and case outcome in 4,341 feeder cattle treated for BRD. Lung auscultation score (P<0.01) and rectal temperature (P<0.01) were predictive of cattle with increased risk for BRD retreatment and mortality. The model-adjusted probability of a calf with a LAS of 2 requiring retreatment was 13%, whereas the probability of retreatment for cattle assigned a LAS of 9 was 63%. An increase in rectal temperature from 100.0 to 108.0°F (37.8 to 42.2°C) was correlated with a 266% increase in likelihood for retreatment for BRD. Risk of death from BRD increased nearly 2,200%, from 1.7% to 39%, as LAS increased from a score of 2 to 9. Risk of death due to BRD increased 196% as rectal temperature proceeded from 100.0 to 108.0øF. These studies demonstrate that lung auscultation score and rectal temperature could be useful to better predict BRD case outcomes in feeder cattle, and to facilitate targeted management decisions.