I think by nuetering him the marking will not be as much.
I believe if a male is nuetered by six months it is much better because the habit has not yet started. Buddy has never marked, however, when my daughter's pug visits he does and it makes me nuts! They are the same age 3 this month and were both fixed at 6mos. I guess it depends on the dog.
Good luck.
Carol & Buddy |