Selective breeding for extreme physical traits has caused a crisis of inherited disease in many purebred dog breeds, with welfare implications for millions of dogs and reform efforts targeting breed standards and health testing.
Brachycephalic obstructive airway syndrome (BOAS) causes lifelong breathing difficulty, exercise intolerance, and sleep-disordered breathing in severely affected dogs. Many owners fail to recognise laboured breathing as abnormal when the dog appears otherwise active. Hip dysplasia in German Shepherds, Labradors, and Golden Retrievers causes progressive joint pain from puppyhood. Hereditary cataract, dilated cardiomyopathy, and syringomyelia impose severe welfare costs on affected individuals. The fundamental cause is breeding for appearance over health — a system perpetuated by demand for visually distinctive dogs.