Why do we perform spay or castration at 6 months of age?
Most veterinarians in the United States recommend bitches and dogs be spayed or castrated between 6 and 9 months of age. This is not based in science; no one has performed a large-scale study in which bitches and dogs underwent gonadectomy at various ages and were tracked throughout life to determine what abnormalities developed relative to age at gonadectomy. It is thought that the current age recommendation arose after the World War II, when increasing affluence of American families first permitted them to treat animals as household pets and were, therefore, more interested in controlling manifestations of reproductive hormone secretion and very interested in making sure the animal survived surgery. Anesthetic and surgical techniques available at that time necessitated the animal be at least 6 months of age.
With current anesthetic agents, anesthetic monitoring equipment, and surgical techniques, it has been demonstrated in multiple studies that bitches and dogs can safely undergo gonadectomy when as young as 6 to 8 weeks of age. Surgical complication rate does not vary between groups undergoing surgery when very young compared to those undergoing surgery at the more traditional age, with overall postoperative complication rate reported as 6.1%. The vast majority of these post surgical complications are transient and do not require veterinary care.
- See more at:
Determining The Best Age At Which To Spay Or Neuter | AKC Canine Health Foundation 3