I just spent a half-hour reading this very well written article. Very cut and dry explanation of the livestock system. Highly recommend everyone to read.
Interesting tidbit: "But a lot of it has to do with the way we grow our food, and the fact that we mix 100 different cows in a single burger. We never used to do that. The butcher used to take the scraps from that one animal and make his hamburger right in front of your eyes. ... Now, you get one infected carcass, and that meat can spread all around the country, because we have this centralized national system."