Evaluation of Thoracic Ultrasonography as a Diagnostic and Prognostic Tool for Early Bovine Respiratory Disease of Feedlot Calves in Western Canada

It is generally accepted that early recognition and treatment of bovine respiratory disease (BRD) improves both prognosis and outcomes, while delayed diagnosis and treatment may result in treatment failure. Methods used to detect BRD in feedlot cattle include the assessment of animal demeanor and behavior by trained feedlot workers ("pen checkers") and evaluation oftransrectal temperature. The serial use of these two methods is currently the most practical, economically feasible, and common means of detecting BRD in feedlot cattle. However, recognized limitations of these methods may result in cattle without BRD being treated unnecessarily, while animals with BRD may remain undetected or be subject to delayed detection, all of which have adverse animal well-being and economic implications. This project investigated the use of thoracic ultrasonography (US) as a diagnostic tool for the assessment of early BRD in feedlot cattle, and evaluated associations between US findings and subsequent animal health and production outcomes.