Feeding grain to cattle is an awful practice that needs to stop; the sooner, the better.
Re: grazing cattle, have you seen Allan Savory's TED talk? http://www.ted.com/talks/allan_savory_how_to_green_the_world_s_deserts_and_reverse_climate_change.html
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.