Sheep pneumonia, caused by a complex of bacterial and viral pathogens, is a leading cause of mortality and welfare harm in housed sheep and lambs, preventable through vaccination, ventilation, and management.
Sheep pneumonia causes acute and chronic suffering that is often underappreciated in production systems. Acute bacterial pneumonia causes fever, laboured breathing, depression, and pain on palpation of the chest — affected sheep separate from the flock, stop eating, and deteriorate rapidly without treatment. Chronic pneumonia results in persistent coughing, progressive weight loss, and exercise intolerance that reduces quality of life over weeks to months. The housing environment is the single most controllable risk factor: sheep in poorly ventilated barns with high ammonia concentrations, excessive humidity, and high stocking density are dramatically more susceptible to respiratory pathogens than those in well-ventilated conditions. Natural ventilation through open ridges and adequate airspace per animal significantly reduces pneumonia incidence. Vaccination before housing provides immunological protection for the period of highest risk. Early identification of coughing animals and prompt treatment with antibiotics prevents spread and reduces individual animal suffering.