We've always followed the philosophy that you shouldn't neuter/spay until growth plates are completely closed. You would need to have x-rays to verify this if the dog is young.
Check out this article about neutering/spaying:
https://www.avma.org/News/JAVMANews/Pages/130401s.aspx
Article Snippet:
https://www.avma.org/News/JAVMANews/Pages/130401s.aspx"Neutering and the age at which a dog is neutered
may affect the animal’s risk for developing certain cancers and joint diseases, according to a study published Feb. 13 in the online scientific journal PLOS ONE.
An examination of health records of 759 Golden Retrievers by researchers with the University of California-Davis discovered
significantly higher incidents of hip dysplasia, cranial cruciate ligament tears, lymphosarcomas, hemangiosarcomas, and mast cell tumors among neutered dogs, compared with sexually intact dogs.
“The study results indicate that dog owners and service dog trainers should carefully consider when to have their male or female dogs neutered,” said the lead investigator, Dr. Benjamin Hart, a distinguished professor emeritus in the UC-Davis School of Veterinary Medicine.
“It is important to remember, however, that because different dog breeds have different vulnerabilities to various diseases, the effects of early and late neutering also may vary from breed to breed,” he said.
While results of the study are revealing, Dr. Hart said the relationship between neutering and disease risk is a complex issue. For example, the increased incidence of joint diseases among early-neutered dogs is likely a combination of the effect of neutering on the young dog’s growth plates and the increase in body weight that is commonly seen in neutered dogs."
Hope this helps!
