I came across the following paper on social media:
The paper considers the the fact that animals are killed in the process of agriculture (15 / ha), whereas if one would use the same area as pasture for foragers, fewer animals would be killed (7.5 / ha). Using these numbers, the paper considers the land area of the US and counts the animal deaths using each approach (using the same land area for both) and suggests that having a diet with meat might actually lead to fewer animal deaths.
However, by using the same area for both the calculations, the paper seems to be implicitly assuming that the calorific value (i.e. number of people you can feed, which is probably the quantity that we want to keep fixed) of 1 ha crops is the same as the calorific value of foragers raised on 1 ha pasture, which seems like a sketchy assumption to make.
Are there studies giving approximate numbers for filling in the missing piece in the calculation?