The Viking colony of Vinland goes as well as historically (not very), but the settlers leave behind some livestock. Smaller animals, either pigs, goats, or sheep. In the case of pigs, they're hardy enough to go feral on their own, and could prove to be useful game. But lets just assume that the natives manage to domesticate/keep domesticated whatever livestock is left behind.
With this new source of nutrition and, in the case of sheep (if we go down that route), wool, what might the impact be on the Americas?