my dog max is 13 months i adopted him at 10 months with no prior training (for the both of us)He has finished beginning training and has been neutered. Problem; when we are at the dog park he goes after the large breed puppies as they enter the park. He barks, growls and snips at them until they respond then he leaves them alone. If they are scared he will become more aggressive. This behavior is similar to how he plays for his tail is wagging and he never bits. I am not worried he will hurt the dogs but the owners do not know this and sometimes he gets so fixated on a dog he wont leave him alone and we have to leave. I have tried to hold on to him and Wait until the dog is in the park before i release him or even doggy time outs but it doesn't always work. He really loves the dog park and playing with the other dogs.What can i do to change this behavior.
find one sturdy, similar-tempered dog (with an understanding owner) that he likes to play with. Every 5 minutes or so, call him out of the play just because, reward him then let him back to play. If he starts bullying, the play ends IMMEDIATELY for that day.
Throughout any playtime, same thing. Call, reward and release if he's playing well. End it (not a time out, an immediate cessation) if he starts acting up. If he fixates on a smaller dog or whoever, same thing - end it.