Monty is a lovely dog, gentle and submissive. when it got towards around 13-14 months he started growing towards intact male dogs. Other dog walkers would say it’s normal and if he was off lead he probably wouldn’t react because he would have more space. Today is was off lead playing with another lab (female) and big german shepherd came into park without warning. Monty ran over befoyI could stop him and i’m sure it looked and sounded worse than it was and he didn’t bite but he was on top of the other dog growling and showing teeth. I managed to get him off and held his harness and I think we were lucky the other dog didn’t turn and bite him. He showed zero aggression until the last couple of months and has had no bad experiences that would have caused this. He is happy to play with figs he knows that are intact. we have he booked to be neutered next month do you think this will help. I am fully prepared to keep him on a training lead until we have confidence he won’t show aggression towards intact males. Do you think it’s a training issue or because he hasn’t been neutered. If it’s training what sort of things can I do to stop him. thanks for any advice or it would be great to hear any of your experiences.