Lefteye is dead on #1 buck or 0 if you can't get #1. Yes, a dove load will (probably stop) the threat at short distance. Why chance it though. I have put the load of shot and the wad of a dove load deep into the back of a rabid dogs head at about 3 yds. but you have let them get waaay to close if you are shooting at that distance. A docter brought in an x-ray to the gun shop a couple of years ago for us to look at. #4 lead at about 15 feet. He said the wound was gruesome, the guy's chest looked like hamburger but only one pellet entered his lung. The doc agreed that if he had been hopped up on drugs there is a good chance the wound would not have stopped him. Any buck is good but #1 is the perfect balance of payload and size of projectile.
"Suppose you were an idiot, and suppose you were a member of Congress, but I repeat myself." Mark Twain