Bovine Respiratory Disease is the leading cause of morbidity and mortality in beef cattle, particularly in weaned calves. Understanding risk factors and welfare-positive management enables better outcomes.
BRD causes progressive respiratory compromise that is painful and debilitating. Affected calves experience fever, laboured breathing, and reduced feed intake; severely affected animals develop pleuropneumonia with fibrinous adhesions that permanently compromise lung function. The chronic poor-doer syndrome in survivors reflects permanent lung damage from inadequately treated early disease. The welfare case for prompt treatment is supported by evidence that early intervention (within 24 hours of first signs) significantly reduces lung pathology severity compared to delayed treatment. Daily welfare monitoring in high-risk groups - trained observation of respiratory rate, posture, and behaviour - enables the early detection that drives better outcomes. The tension between metaphylaxis (group antibiotic treatment at risk periods) and antibiotic stewardship requires careful case-by-case evaluation balancing immediate welfare benefit against resistance risks.