Thank you, I actually didn't know this! I'd always heard about the proportion of animals that were raised on grain, as well as the percentage of crops used for

Thank you, I actually didn't know this! I'd always heard about the proportion of animals that were raised on grain, as well as the percentage of crops used for animal feed, and concluded that in the US at least the majority of cattle were raised in feedlots their entire lives. Turns out you're right, the majority start out on pasture and then are transported to feed lots to fatten up once they reach maturity. According to this[1], due to the fact that grass fed beef fatten up more slowly, end up at a lower overall weight at slaughter, and are kept alive and emitting longer, "a nationwide shift to exclusively grass-fed beef would require increasing the national cattle herd from 77 to 100 million cattle, an increase of 30%", and "the current pastureland grass resource can support only 27% of the current beef supply (27 million cattle)". Further - "Emissions of methane, a greenhouse gas with a large warming effect relative to carbon dioxide per molecule, come from beef cattle in the forms enteric fermentation and manure emissions. We calculated a 43% increase in methane from enteric fermentation (table 2), assuming that cattle finishing on grass had the same daily methane emissions as present-day stocker cattle, who have nearly identical ADG and are fed primarily on roughage." Either way it seems as if grain is an indispensable part of animal agriculture currently, so we have to take that into account when talking about what would happen to land use with or without the cows around. Additionally, it seems that moving away from grain would potentially have even worse impacts on the climate. [1]https://iopscience.iop.org/article/10.1088/1748-9326/aad401 https://iopscience.iop.org/article/10.1088/1748-9326/aad401