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					Originally Posted by PennysMum  Hormonal changes don't kick in until several weeks after a neuter! It might take up to eight weeks for him to mellow if he is going to mellow-- one week is definitely not enough time to know if the surgery will help matters. | 
 
  Very true, it does take time for the neuter to work. And that is true with both male and females. 
And please no collars, will only make him mean.
You need to keep him away from all other animals for all their safety.
Good luck and if it doesn't work then give him to a rescue, as they will train him.