The closed studbook system used in pedigree dog breeding has created severe genetic bottlenecks in many breeds, causing inherited diseases and reduced immune competence that compromise welfare.
Inbreeding depression causes welfare harms that extend across the entire lifespan of affected dogs. Dogs with high inbreeding coefficients are more susceptible to infections, recover more slowly from illness, and are more likely to develop the breed-specific inherited conditions that require painful treatments or cause chronic discomfort. Many of these conditions have been known for decades but persist because breed standards and registration rules create perverse incentives against genetic diversification. Regulatory pressure on kennel clubs to open studbooks and mandate minimum diversity requirements is the most effective policy lever available.