I: THE LAND I think that perhaps there is a point that is missed in this discussion. Cattle are one of the most distructive livestocks one can raise on land. They tear up the sod as they rip up the grass. Have you ever tried to walk across a pasture which has held cows for more than a month? It's pure muck. If there are any clean streams running through a pasture they ruin its flow, and turn it into a muddy mess.
This is why cattle ranchers need hundreds or thousands of acres to raise these beasts. Runoff, loss of topsoil and errosion are all effects of ranching.
II: ANTIBIOTICS/SUPER BACTERIUM
The over-use of antibiotics and their eventuall runnoff into the land and nearby streams are creating another hazard: Bacteria which are resistant to antibiotics. Bacteria are extremely agile lifeforms. When a bacterium is attacked it will shoot out "branches" to grab any available chromosomes and place it, seemingly at random, in its own to attempt to create a resistance to the invader. Often of course this fails. But when it does not, it can communicate, or "teach" other bacterium what it has learned. The result: Antibiotic resistant bacterium. This has come into the news slightly over the past few years but it isn't something people want to hear (especially the part about the drug companies not creating new antibiotics because "research costs too much", and what happens when it's "too late".
III. Land Use.
The land used to raise such a small percentage of the worlds food supply, could be used to feed ALL of the worlds population if it produced vegetables, grains, and soy products.
Just a few things to consider...
None.
