Dog neutering is a very popular practice in the United States. In doing so, people hope to avoid overpopulation or various unwanted behaviors. But is it a good choice for dogs, health-wise?

The UC Davis School of Veterinary Medicine conducted a study with hopes of determining whether or not neutering is detrimental to canine health, and chose Golden Retrievers and Labrador Retrievers as their subjects. The two breeds, which have been accepted worldwide as exemplary family pets and service dogs, are very similar in behavioral disposition, body size, and conformation, and were labeled as conducive to a comparative study.

“…The incidence rates of both joint disorders and cancers at various neuter ages were much more pronounced in Golden Retrievers than in Labrador Retrievers,” notes Benjamin Hart, DVM, Ph.D., a distinguished professor emeritus in the School of Veterinary Medicine.

The long-term effects mentioned included joint disorders like hip dysplasia and cranial cruciate ligament tears, and cancers deemed “devastating”.

A connection was also found between early sterilization—before the animal is 6 months old—and the appearance of joint disorders. About 5 percent of intact Golden and Labrador Retrievers of both genders suffer from a joint disorder, the researchers determined. The rate in dogs sterilized before 6 months old jumped to 10 percent of Labs and 20 to 25 percent of Goldens.

The removal of hormone-producing organs during the first year of a dog’s life leaves the animals vulnerable to the delayed closure of long-bone growth plates, explains lead investigator Dr. Hart.

“We found in both breeds that neutering before the age of 6 months, which is common practice in the United States, significantly increased the occurrence of joint disorders, especially in the golden retrievers,” says Dr. Hart.

While neutering doubled joint disorders in Labradors, neutered Golden Retrievers saw their rate of joint disorder jump to four or five times that of Goldens that had not been neutered. Golden retrievers also saw a similar discrepancy in cancer rates, but with only female Goldens significantly affected. The study found that female Goldens that had been neutered had their risk of cancer rise three to four times that of non-neutered females.

The researchers did not take a stand on spaying and neutering, which is done to an estimated 83 percent of all U.S. dogs to control the pet population and prevent unwanted behaviors. Instead, they stated that the study served to measure the long-term health effects of sterilization and to educate breeders and dog owners who are deciding when, and if, to spay or neuter their animals.