Two questions - is it REALLY necessary to do this? and also, once they are removed, do the goats still butt each other as if they were there? 
Its really your decision!
Pygmies, Bagots, Old English goats aren't usually disbudded...
Done properly, its rare for problems to occur.. If you bear in mind that the vet is cutting a hole in the thin skull of a young animal, and scurs (regrowth) can happen if the whole horn bud isn't removed.
Any knocks while healing can bleed profusely.
And yes, they can still butt without horns. Its the action, playing or fighting, they don't mind whether there's anything on their head - its the body language!
Our Bagot billy has lovely horns - he's very gentle even if the girls are "butting" (and uses them mostly as a back scratcher!) as the girls are disbudded.