My father always explained that interest for rusty metall with the cows attempt to balance out a iron-deficiency. Could be wrong though.<p>Found there behaviour always fascinating. They internal groom-group friendships and the one or two weakest cows they would trash up to feed them too any predator(yes, they have a social life in that way).<p>Not happy how dairy farming selective breeding has crippled them. If you have to inject a hormon into a creature for milking, else it gets sick, you have overstreched it to the point of crippeling.<p>still like farmers though and without them cows would go the way of everything wild in that juicebox that is earth.