Respiratory disease is one of the most prevalent welfare problems in intensively housed pigs, with significant impacts on growth, comfort, and survival.
Respiratory disease in pigs is both welfare concern and productivity signal — sick pigs grow slowly, eat less, and experience chronic malaise. In conventional systems, high pig density in poorly ventilated buildings creates ideal conditions for airborne pathogen spread, making respiratory disease endemic rather than occasional. Preventive welfare — combining ventilation standards, stocking limits, all-in-all-out management, and vaccination — dramatically reduces disease burden. Higher welfare systems such as outdoor rearing show markedly lower respiratory lesion scores at slaughter, confirming that environment, not only genetics, drives disease prevalence.