Castration!!

Question
I am considering having my 7 and a half year old Jack Russell castrated. He has a lovely temperament with people but does have a lot of aggression towards other dogs, mainly males, but generally to any big dogs. He will play nicely with smaller dogs, sometimes even males, but if he got the chance he would take on any big dog, regardless of whether they even take any notice of him! I am not expecting miracles from the castration, especially at his age, I just thought that if there was a slight improvement, that it would be worth it. However, if I felt it might make him worse, I would refrain from doing it. Can you offer me some advice?

Answer
Hi Jo,
It definitely won't make him worse, and is always a good thing to have done to eliminate the chance of unwanted puppies. When the testes are removed, testosterone is obviously not produced, and when testosterone is gone, that male "drive" aggression is significantly diminished.
I believe you will see a dramatic change in his temperament but he might always feel "threatened" by bigger dogs and flex his Jack Russell muscles. It's just part of who they are, but that strong "fight" drive will be markedly less intense. At least that has been my experience. Make sure he has a good physical before surgery as he is getting up there in age (almost 63 in dog years!) Get approval from your veterinarian as she will know best as to whether it would be worth it or not for your handsome hunk. Good luck!!