thatbags, the problem is that most meat doesn't come from animals grazing on less fertile, hilly areas, but from intensively reared livestock, which depend on the kind of imported feeds such as GM soy that are destroying forests and poisoning communities in places like South America. And even grazing animals have their environmental impacts - for example, if sheep didn't graze grassy uplands, there would be more vegetation on the hills which would absorb more water and reduce the risk of flooding.
DebnCreme, I think you misunderstood me - my whole point was that you do have the right to make an informed choice. And no-one's suggesting that we stop farming animals altogether, just that we do it as sustainably as possible, so as your grandchildren cycle past singing "Old MacDonald" they can see cows, sheep, chickens and pigs rather than a series of industrial facilities.
Mamie, you're right, if you do choose local, sustainably farmed meat, that's clearly going to have less of an impact than intensively reared beef or chicken. But you say the cattle near you still need fodder, so wouldn't it be more efficient (although perhaps less financially viable) for the farmers to grow crops for us to eat directly than it is to grow fodder to feed to the cattle so we can eat them or drink their milk?