We searched long and hard to find the right vet for us and our program. The one that we found is the most knowledgeable and straight forward vet that we have ever met. He advises us to have our pups fixed around 6 months of age. This has proven to work out perfectly. Other vets say to wait until the pup matures. This is only a theory for now and has not been proven to make any type of difference. Pups that are fixed at an early age have turned out to be larger in size and have less health issues that could arise prior to fixing.