Huh? I've raised quite a few foals over the years and watched the moms "discipline" them. From what I have seen, in mare/foal behavior, and in general herd behavior, as well, is that discipline is only used when needed, and it's always appropriate. Lead, or dominant, mares, use body language and the "ugly face" a lot, to get their point across. They don't resort to actual "violence" very often. If people acted the same way, I think we'd have many less criminals and sociopaths - not more. And no child abuse.
I wish people were more like horses. Of course, I've always felt that way.