Seriously, what is the basis for this idea?
AFIAK, live stock are not fed coal or petrol. So any carbon that they emit must come from the CO2 that was stored in te plants that they eat during there lifetime. So how does that add to global warming? If the plant material was not eaten by the live stock, it would have been eaten by other animals (like humans) or would have rotted away.
Humans can't directly digest most plant material so we have to burn fuel to cook it, thus producing CO2. Also raw plant material has less calories/kg then most meats, we would have to transport more to feed all people in the world. If other animals animals ate the plants I don't see why the would not produce the same amount of gasses compared to live stock. If it was rotting away, some of the material would eventually become coal, but most of it would enter the atmosphere as methane.
So how am I wrong here?