Porcine respiratory disease complex is a leading cause of illness and mortality in intensive pig production, with housing ventilation, stocking density, and pathogen control as primary welfare levers.
Porcine respiratory disease represents one of the most common causes of suffering in commercial pig production. The disease complex involves multiple interacting pathogens that cause pneumonia, pleuritis, and systemic illness in pigs that experience fever, respiratory distress, and loss of appetite for extended periods. Housing conditions — particularly poor ventilation and high stocking density — dramatically influence disease incidence by impairing the respiratory immune defenses that protect pigs from the pathogens ubiquitous in intensive environments. Management reforms that improve air quality and reduce pathogen pressure directly reduce the frequency and severity of individual pig suffering.