This document discusses the efficiency of dairy ruminants in utilizing land areas for food production. It notes that dairy ruminants are net producers of protein for human consumption, as they can utilize plant proteins that humans cannot eat. However, they do utilize significant agricultural lands, both arable and non-arable. The document outlines a methodology to determine the land area required to feed dairy cattle herds and whether the same land could potentially produce more plant proteins directly for human consumption instead of through animals. It notes that the results are variable depending on factors like the proportion of arable lands used and estimated long-term plant yields. Many questions remain around rotational crops, soil fertility impacts, and accounting for the nutritional quality difference between plant