Oh – I can just feel the controversy in the air rising! Can you? Okay, let’s just get right into it! We’ll tackle dogs first.
From the perspective of how small the incision is to how quickly they bounce back from surgery, 3-4 months of age is a great time for this procedure. For decades, veterinarians have talked about how just one heat cycle increases a female dog’s chance of mammary cancer 300%. And, of course, you can’t get testicular cancer if you don’t have testicles.
But, recent evidence shows dogs allowed to keep their parts until they are 2-3 years old are at lower risk of other types of cancer and won’t have really small vulvas which can happen to females spayed early.
So, there’s a trade off – the older a dog gets, the more her risk of uterine infection. (Note from my office: For any intact female who is ill, pyometra (uterus infection) is high on the list of possibilities!) For people who can control their intact male, there may be very little reason to have him neutered. Realistically, however, accidents happen all the time. And, intact males do tend to get perianal tumors (masses around the rectum) – a condition that is cured 70% of the time by castration.
For cats, there’s less controversy and little argument: Most people say fix em! Three pounds is the perfect size.