Yesterday was the last straw, we were at the dog park and my sister brought her new puppy who he had never met. I thought a neutral place like the dog park would be a good place to introduce them and he lashed out at her. Again didn’t bit or scratch her just growled and went for the neck.
My dog is very socialized and very well behaved he loves kids and other dogs, he's a mutt and weighs about 90 lbs we were told bull mastiff, chocolate lab and German wirehaired. We have been going to the dog park since he was 4 mo. old. We also recently got a new dog in March who was 6 mo. old at the time and they get along great.
Sorry for the long post, any help/ advice/ experience with this would be greatly appreciated!
Re: Recent aggression with puppies, Please HELP!