[teslabox]

I have an old book somewhere that said the dairy cow is the most efficient way to convert the grass on a rocky hillside into human-usable protein.

Meat is rather inefficient. Temple Grandin is an autistic woman who designed more humane slaughterhouse systems. A quote in the HBO movie about her sticks with me: "Nature is cruel, but we don't have to be."

https://m.imdb.com/title/tt1278469/?ref=m_nv_sr_1

[firethief]

Great. Where can I find milk from cows that live off the grass from rocky hillsides?

[davewasthere]

Switzerland/France. I've seen farmers take their mobile milk-carts up mountains to milk them in-situ. Not sure whether they do the same thing with calves or not though.

[microtherion]

So called "Mutterkuh-Haltung", where the calves are kept with the mother, is increasingly popular. This occasionally causes problems, as hiking paths often intersect grazing ranges, and cows will defend their calves aggressively from perceived threats.