Beef resource intensity reflects exceptional parental feed needs that resist technological improvement

Abstract

Beef is the most resource-intensive mass-consumed human food. This holds for greenhouse gas emissions, cropland, rangeland, and nitrogenous fertilizer use, and feed consumption per g meat, g protein, or calorie. Why is beef so exceptional, even compared to other meat producers like pork or poultry? Here we investigate this question by comparing beef, pork, and poultry production. We show that the resource intensity of beef production is primarily due to the feed requirements of its reproductive stock. While the share of total feed consumed by the reproductive stock is 3-8% for poultry, and 20-30% for pork, it is 50-60% for beef. This result has a simple, two-part explanation. First, cows birth rates are far lower than those of sows or hens (order 1, 10, and 100 young y-1 resp.), and calves take about 5-10 times longer to mature than piglets, so many more breeding animals are needed for a given meat output. Second, cattle are larger than these other common livestock, with correspondingly larger maintenance energy needed to sustain the reproductive stock. These results may motivate breeding smaller, more fecund, less carbon intensive cattle. We show that even if cattle fecundity is doubled, body size is halved, and cattle methane emissions are simultaneously biotechnologically cut in half, this hypothetical “perfected” beef is still no less resource intensive than pork, and much more intensive than poultry and plant based alternatives.