Comparison of thoracic auscultation, clinical score, and ultrasonography as indicators of bovine respiratory disease in pre-weaned dairy calves

Abstract

Various strategies have been adopted to mitigate the impact of bovine respiratory disease (BRD) in dairy replacement calves. The diagnosis of BRD is challenging because there is no gold standard for its diagnosis on-farm. Several subjective scoring methods, such as the Calf Respiratory Health Score (CRHS) from the University of Wisconsin, which is based on rectal temperature, and subjective assessment of cough, ocular-nasal discharge and ear drooping, are available to help dairy producers identify calves with BRD. Additionally, practitioners can use thoracic auscultation, a fundamental part of the physical examination, to aid in the diagnosis of BRD. Recently, thoracic ultrasonography (TUS) has been used to detect calves with lung consolidation secondary to bronchopneumonia. The objectives of this study were to compare the different tools available for the diagnosis of BRD in preweaned dairy calves, and to assess the association of lung consolidation on the risk of dying within 30 days after the initial examination.