Cattle Respiratory Disease in Feedlot Calves

Bovine respiratory disease complex (BRD) is the leading cause of death and suffering in feedlot cattle, causing significant suffering in millions of calves annually across North America and globally.

Key Facts

BRD accounts for over 70% of illness and 40% of deaths in North American feedlot cattle
It typically occurs within the first 45 days of feedlot entry when stress and mixing expose calves to pathogens
Mannheimia haemolytica, Pasteurella multocida, Mycoplasma bovis, and BRSV are primary causative agents
Lung damage from severe BRD causes permanent production impairment even in survivors
Visual assessment of clinical signs misses up to 60% of affected calves — electronic monitoring improves detection
Metaphylaxis — mass antibiotic treatment at feedlot entry — reduces outbreak severity but raises AMR concerns
The BRD Coordinated Agricultural Project has driven improved diagnostic tools and management protocols

Welfare Considerations

Feedlot calves with BRD experience fever, difficulty breathing, and the accumulated stress of transport, weaning, mixing, and dietary change all preceding the disease episode. The first days of feedlot entry are a compounding welfare insult in which respiratory disease emerges in an already stressed animal. Calves that develop severe pneumonia and survive may carry permanent lung scarring that impairs their breathing for life. The high proportion of subclinical BRD — missed by visual observation — means many calves suffer without treatment.

What You Can Do

Support farming practices that reduce transport stress and mixing of cattle before feedlot entry
Advocate for antimicrobial stewardship in feedlots that prioritises targeted treatment over mass prophylaxis
Choose beef products from producers with certified BRD management and low disease incidence rates
Support research into BRD vaccination protocols and electronic monitoring systems
Encourage feedlot operators to invest in twice-daily monitoring of newly arrived calves for early disease detection