Agree with Dixie, 14 or more are preferable, though 12 is part of the saddleback standard.
I would typically look for 14 teats for a breeding female, but you can breed from a 12 teat - only a problem if they have large litters.
Boars are "half the young", so the number of teats on the boar affects the offspring, so you should look for a boar with 14 or more as well.