Respiratory disease is endemic in intensive pig housing, causing chronic welfare harm that better ventilation, stocking density, and biosecurity can significantly reduce.
Enzootic pneumonia causes chronic welfare suffering: pigs with clinical disease show persistent coughing, reduced feed intake, retarded growth, and lethargy. Sub-clinical infection causes lung lesions visible at slaughter even when clinical signs were absent — indicating ongoing welfare compromise below the threshold of detection. The condition is largely preventable through air quality management and appropriate stocking density, making endemic respiratory disease in pig systems a welfare failure that farm management can address.