I have a 3 year old Catahoula mix who is wonderful in the home and very obedient and submissive, but outside or on walks he completely ignores me when something distracts him. He is very agressive toward other dogs while on a leash, and sometimes at dog parks, although it seems to go up and down - some days he is very friendly and others he is aggressive toward multiple dogs. What can I do>? I got him from the pound and I know he wasn't socialized as a puppy but I am at my wit's end trying to walk him around other dogs!