[quote=CatStamm]I think it's best to alter them right before there 1st heat cycle.[/quote]
Actually it isn't. Amanda is right. This might be of interest to you:
It doesn't only relate to canine athletes either. Personally I'm not at all in favor of spaying dogs before maturity.
Of course in certain cases it can't be helped, like for example when adopting from a shelter that won't release a pet until it's spayed/neutered, but as a whole the procedure is not as harmless as many of the animal rights people want to make pet owners think. That's why I am so vehemently against this whole "mandatory spay/neuter" bullshit - it's a major decision for a dog's life-long health, and should be up to the owner, not the government. (Sorry to be blunt! :p lol)