The Great Spay/Neuter Debate: Does Early Gonadectomy Prevent or Cause Disease in Dogs?

Traditionally, veterinarians have recommended that dogs be spayed or neutered at approximately 6 months of age. For most pet owners and veterinarians, this is a convenient time. It allows pets to complete their initial vaccine series while still performing the procedure prior to sexual maturity. After all, it is common to recommend spaying prior to a pet's first estrus period to help protect against mammary cancer. Likewise, it is common to recommend castration prior to the onset of undesirable behaviors, such as aggression and urine marking, which can be associated with male sexual maturity.
Source: Advances in Small Animal Medicine and Surgery - Category: Veterinary Research Authors: Tags: Guest Editorial Source Type: research