[geoschmo]

This is an uneducated comment here, because I am by no means an expert. But I thought I read somewhere that the reason for feeding animal protein to animals has more to do with the cost of disposing of it by any other acceptable means then it has to do with the cost of animal protein relative to vegatable protein. Processing of animals into meat results in a lot of waste byproducts afterall. You can't exactly dump it down the drain.