The two situations aren't really comparable without more information. Clearly the people in A are still eating a craptonne of plants, and also have access to much more land per person than B, since they can afford to have a lot dedicated to very unproductive pasture.

Yeah, it's hard to compare and the greater yields of crops certainly bodes well for A.

Though the productivity differences aren't as large as one would think - protein conversion ratios for smaller animals tend to be 2-3. It's worse for beef (~10) but you have to consider that half the cows are creating milk which has a high protein conversion ratio. And it's potentially even better for animals when you consider the quality of protein - e.g. see https://onlinelibrary.wiley.com/doi/abs/10.1002/jsfa.8362

> It's worse for beef (~10) but you have to consider that half the cows are creating milk which has a high protein conversion ratio.

Half?

Only female cows produce milk.

Where do you get "half" from that? Female cows are economically productive and males are not. The ratio is not even close to half-and-half. Go look at a herd of cows sometime.

All cows are female.

In common parlance (rather than technical terminology), "cows" means "cattle".

Almost all cattle are female. aflag doesn't get less accurate if you interpret "cows" as the species term that it is.

Pastoral societies usually inhabit ecosystems that don't support human-edible crops

False dichotomy. Animal farming takes up nearly 80% of global agricultural land. Switching away from livestock would reduce the need for land clearing, not increase it.