I haven't mentioned cows, pigs, or any other earth animal being brought along by the colonists, other than dogs and cats. Cows and pigs and other animals have to eat, and so would need to be genetically altered, just like the humans, to eat plants grown on Benteen. Would the locals be eating siffle burgers if they had beef?
Still, since I didn't specifically address that issue, we can assume that the human tendency to 'find a way' would prevail here, too! Bring on the bacon!