Dominant Male--fighting with strangers

Question
QUESTION: My 4 year old male lab is a very mellow easy going dog most of the time until an unfamiliar male dog is around, then he wants to show his dominance and fight, raise hair on neck, growl, show teeth, etc.
Is there anything that I can do to keep him from doing this, or at least not the growling and teeth showing?  I know that's his instincts and he knows that I'm alpha to him but other male dogs, he's the alpha.--He is not neutered, as he is a stud.
Thanks for your advice.

ANSWER: The solution is to quit using a dog aggressive dog as a stud. Get him neutered.  We have plenty of fine dogs to use for breeding.  There is no excuse for using one with behavior problems.  Sorry.

---------- FOLLOW-UP ----------

QUESTION: FIrst of all he has not been bred yet.  Secondly, this has just recently within the past 2 months started with the agression toward other dominant male dogs, not people.
Had hoped there may be a method to work with him to keep it from escelating, etc.  I don't think you can breed out some of the wolf traits such as alpha and beta dogs, in this case, I'll have to disagree and say that neutering is not the answer.

Answer
While breeding isn't an exact science, many dogs have temperaments much like at least one of their parents.  Any group of dogs put together will sort themselves out, each having a pack rank.  However, some dogs are much more aggressive about it.  Using a dog that is very aggressive about it for breeding stock risks perpetuating the problem.  We should only be using the very best.  I frequently see large gatherings of carefully bred, intact dogs, and seldom see any such problems.  Breeding out behavior problems can, and should be done.