Porcine respiratory disease complex is the leading cause of production losses and significant suffering in commercial pig farms, with prevention through improved housing ventilation and management offering major welfare gains.
Porcine respiratory disease represents a widespread and persistent welfare problem in commercial pig production because the housing conditions that maximize production efficiency, including high stocking densities and continuous throughput, also create environments favorable for respiratory pathogen transmission. Ammonia from accumulated manure at concentrations routinely found in poorly ventilated pig buildings damages the respiratory epithelium, reducing its barrier function and creating opportunities for opportunistic pathogens. Pigs with respiratory disease experience the sustained discomfort of labored breathing, reduced activity, painful coughing, and systemic illness. The welfare benefits of good ventilation design, appropriate stocking density, all-in-all-out management, and strategic vaccination extend beyond respiratory disease to the overall health burden that determines daily welfare experience for pigs throughout their production lives.