We have a 10 yr old neutered male. He lost his brother 2 yrs ago. Last september we introduced another male Jack puppy. Introduction went great haven't had any problems. Got the new pup neutered in July and about 2 wks later old dog attacked pup viciously. Then nothing until this week. Older dog suffered from summer allergies with extreme rash on stomach so vet gave him a steroid shot. We have had 3 fights this week. Always different places and older dog is attacking and grabbing for pups neck. Pup fighting back/defending. Pup has longer legs and pushes older dog away his legs are chewed up bad. What is happening? Establishing alfa male even after this long? Why did it happen AFTER neutering? Steroids for allergies causing problems? Help!