As far as I can tell cows can still produce B12 with the help of their symbiotic bacteria and digestive tract, and humans can't. The point is that it takes a l

As far as I can tell cows can still produce B12 with the help of their symbiotic bacteria and digestive tract, and humans can't. The point is that it takes a lot of attention and artificial help to have a healthy vegan diet. That's not great for children or half-committed adults. Eating meat, or at least eggs or dairy, cuts out a lot of that effort. The animals have already done the work of turning a vegan diet into the large variety of nutrients that we need.