Bovine Respiratory Disease (BRD) complex is the leading cause of morbidity and mortality in beef cattle globally, causing profound welfare impacts and significant economic losses exceeding USD 2 billion annually in the US alone. BRD involves viral pathogens (BVDV, IBR, BRSV, PI3) predisposing cattle to bacterial pneumonia (Mannheimia haemolytica, Pasteurella multocida). Clinical signs include fever, nasal discharge, coughing, laboured breathing, and depression indicating significant distress. Welfare compromise begins early: subclinical BRD reduces growth and causes chronic lung damage detectable at slaughter in 30-40% of feedlot cattle. Prevention relies on vaccination protocols, metaphylaxis at processing, stress reduction during transport and mixing, and adequate nutrition. Early detection using automated health monitoring systems - including accelerometers, feeding behaviour sensors, and infrared thermometry - enables prompt treatment improving welfare outcomes.