Meat Production Methods

Raising an animal for meat means feeding it grain or forage for months or years before you get any edible product back. The feed conversion ratio, FCR, tells you how many kilograms of feed it takes to produce one kilogram of live weight. Beef cattle run around 6 to 10 to 1, pigs around 3 to 1, and chickens around 2 to 1. Cattle are so inefficient partly because they're big, slow-growing animals, and partly because they're ruminants: bacteria in their stomachs ferment plant fiber and release methane as a byproduct, a potent greenhouse gas that pigs and chickens don't produce nearly as much of. Lower FCR means less grain grown, less land plowed, less irrigation water pumped, and less fertilizer runoff per kilogram of meat.

Land and water use stack on top of feed. Cattle need pasture for grazing or cropland for feed corn and soy, plus water for drinking and for irrigating that feed, so beef's land and water footprint per kilogram dwarfs chicken's. Concentrated animal feeding operations, or feedlots, pack thousands of cattle into small areas to fatten them quickly, which saves land but creates a new problem: waste. Manure and urine from thousands of animals can overwhelm a nearby stream's capacity to break it down, causing nutrient loading, eutrophication, oxygen depletion, and pathogen contamination downstream.

This all connects back to the 10 percent rule from energy flow through trophic levels: only about 10 percent of energy at one level transfers to the next, so eating meat means eating an animal that already burned 90 percent of the energy it ate. Growing grain to feed cattle, then eating the cattle, costs far more land and water than eating the grain directly.