I have 3 dogs. When ever I take my dogs to the vet or groomers (and leave one at home), the 3 yr old one won't leave them alone when they get back for at least 2 weeks. Humping, guarding attempting to bite. If I get him fixed will this stop? One of my dogs is 15 and has hip problems, he is 50 lbs and the one humping him is 15 lbs. I think he is going to get hurt from this extra weight on his rear end. The more we try to stop the smaller dog, the more frantic he gets.

I think neutering is a good idea. It may not completely stop the humping, since he has learned the behavior. The other dogs smell different when they get home, and he is probably trying to reestablish the social order. Lower hormone levels usually translate into less anxiety.