Aggresion in male bulldog

Question
Good Day,

We have a male english bulldog who is a year and a half right now. When he was a puppy he was really good and never got into any fights with our other dog. Right before we got him neutered he started attacking our other dog and pinning her into corners, also he will bite my girlfriend for no particular reason and will terrorize my nieces. We jumped on the problem right away with correcting him and getting him fixed. Since being fixed and training with him we have seen no improvement, he has not even slowed down at all. Whenever he sees a bigger dog now he gets into fights with them as well. We have brought him back to the breeder and she is also baffled by his attitude. We have contacted a few other people and they are unsure of what to do. Currently he is on vallarium root to take off some of the edge on him and it does not seem to be making a difference either. Is their anything you can suggest to help him?  

Answer
I've seen this behavior, as far as dog aggression goes, in dogs who are neutered late and once the behavior has already started.  That's why I always recommend having males neutered no later than 6 months of age.

Now, the human aggression is another story. I wouldn't tolerate this behavior for a minute. If this continues, you have some hard decisions to make. No dog is worth the well being of a child.

Bad temperament is inherited. You can't beat a good tempered dog into biting a child usually.

The long shot diagnosis is perhaps a brain tumor that has caused a turn in his behavior.