The optimal timing of spay and neuter surgery in dogs is more nuanced than previously thought, with emerging evidence that early surgery may affect health outcomes in some breeds.
Spay and neuter timing is an area where welfare-optimal decisions require individualized veterinary guidance rather than a blanket protocol. The evidence now clearly shows that the welfare calculus differs between breeds, sexes, and individual circumstances. For large and giant breed dogs, delaying neuter until after growth plate closure may reduce joint disorder risk significantly. For shelter dogs placed in uncontrolled environments, early surgery prevents litter welfare problems at population scale. The welfare-optimal approach combines access to veterinary guidance on breed-specific timing with responsible ownership that prevents unwanted breeding in intact animals.