I have a beautiful 2 year old neutered male Labrador. He's a lovely dog, good with the kids, plays nicely with other dogs. However he has had run ins with two dogs. Both of these dogs have issues and have been off the lead and had a go at him. Now when we see these dogs in the field he changes, hackles go up, barks, growls and if he is off the lead ( & I haven't seen these dogs to put him back on) he will chase after them. Usually he will get so far and then come running back. Today however he ran straight over to a little black dog. It all happened before I noticed the dog was so close. All recall training went out the of the door. To be fair, when I got a hold of my dog, she said it was her dogs fault for starting it. I avoid these dogs where possible but sometimes they just appear. Any advice? My dog is scared, but he reacts aggressively. He's a big dog.