[blacksmith_tb]

Certainly some cattle are grazed on land that would be too hilly / rocky etc. to farm. And that's not a terrible use of land, but enormous numbers of cattle are raised in feedlots, and fed cereal crops like corn (maize) which have to farmed on the better farmland, which is far less reasonable.

[hombre_fatal]

The non-arable land meme comes from a paper that considered land non-arable if it had 25% crop yield (due to things like bad soil or too rocky or too much of a grade). Yet the things that make land non-arable also reduce their yield for animal ag on that same land.