Traditionally, vets have advised de-sexing pets (both dogs and cats, male or female) at an average of 6 months of age. This is very much based on historical habit, rather than on any scientific facts. Due to the emergence of early de-sexing (as young as 12 weeks of age), there has been some good scientific research done on the effects of de-sexing, both at young ages (12 weeks), and at 6 months of age. The research information has given us reason to re-think our general advice on the age of de-sexing. Early de-sexing has been linked to an increased incidence of growth deformities like hip dysplasia and elbow dysplasia, particularly in the larger breed dogs. It has also shown an elevated risk of certain types of cancer – particularly Lymphoma, Osteosarcoma and haemangiosarcoma. All of these findings were still present when large breed dogs were de-sexed at 6 months of age. These findings have led us to now advise owners of large breed bitches to wait until they have their first season (age from 9 months up to 18 months) before desexing, and for male dogs, to wait until they reach sexual maturity (again, age is relative to breed size – 14-18 months old). Another more recent option available is to perform an ovary-sparing spey procedure, where the ovaries are left intact, and only the uterus is removed ( so performing a hysterectomy rather than a full ovarian-hysterectomy). In male dogs, you can also do a vasectomy, which leaves the testicles intact, but removes fertility, but this does leave dogs with some perhaps less desirable masculine traits – fighting, inter-dog aggression, wandering and escaping – as well as issues with both testicular and prostate cancer in later life. So, we do advise a full castration once the dog has reached full maturity.