Bovine Respiratory Disease (BRD)âcommonly called calf pneumonia or shipping feverâis the leading cause of disease and death in calves worldwide, causing enormous welfare harm and economic loss. BRD is a multifactorial syndrome involving pathogen exposure and the stress events that impair immune defenses, making prevention as much a management issue as a medical one.
BRD causes fever, labored breathing, nasal discharge, depression, and significant pain from lung inflammation. Calves with pneumonia experience respiratory distressâthe subjective experience of difficulty breathing is among the most aversive of welfare harms. Chronic cases develop scarred lung tissue, permanent respiratory impairment, and reduced productivity. Calves that survive severe BRD may never achieve full welfare or productive potential.
Weaning, transport, mixing with unfamiliar animals, and poor nutrition all suppress calf immune function through cortisol-mediated mechanisms. BRD outbreaks characteristically follow these stressful management eventsâparticularly weaning and market purchase. Low-stress weaning methods (fence-line weaning, two-stage weaning) significantly reduce BRD incidence by limiting immune suppression at this vulnerable transition.
Calves are born with no antibodies and depend entirely on colostrum for initial passive immunity. Colostrum failureâfrom inadequate quantity, quality, or timingâcreates immune-compromised calves highly susceptible to BRD and other diseases. Best practice: 4 liters of high-quality colostrum within 2 hours of birth. Colostrum management is the single most welfare-impactful intervention in early calf life.
Prompt antibiotic treatment with NSAIDs for pain relief, initiated within 24-48 hours of first clinical signs, dramatically reduces suffering duration and improves outcomes. Delayed treatment increases the likelihood of chronic lung damage. Early identification is the bottleneckâtwice-daily observation of calves, particularly during high-risk periods, is essential.
Part of the Animal Welfare Hub â 2365+ pages of evidence-based animal welfare information.