Brachycephalic obstructive airway syndrome causes chronic respiratory distress in flat-faced breeds; corrective surgery dramatically improves quality of life and welfare.
Brachycephalic dogs live their entire lives unable to breathe normally - a welfare compromise normalized by public familiarity with the breed. Many owners don't recognize their dog is struggling because they have never known the dog when it could breathe easily. After surgery, owners report dramatic improvements in activity level, sleep quality, and energy. The deeper welfare problem is continued selective breeding for these traits.