> Those require processing, and often times the supplement industry isn't exactly that clean. (I'm looking at you cheap fish oil sups) B12 comes from bacteria,

> Those require processing, and often times the supplement industry isn't exactly that clean. (I'm looking at you cheap fish oil sups) B12 comes from bacteria, and is very frequently supplemented into cattle as well. Animals do not produce their own B12, it's from bacteria consumed in the soil. https://www.agric.wa.gov.au/livestock-biosecurity/cobalt-deficiency-sheep-and-cattle https://www.agric.wa.gov.au/livestock-biosecurity/cobalt-def... > Also you should consider the efficency of what the equillence of plans would take. (More plants requires more land+water, which requires more infrastructure, more transportation, etc). Also, don't forget about soil quality and erosion. You can't just grow infinitely on the same land. Let's not forget yield loss due to pests and diease. > Cows are huge and they feed a lot of people with very little waste. (Assuming you don't throw out the organs and bones) I am not sure what you think feeds animal agriculture. Huge amounts of plants (and therefore fossil fuel energy via fertilizer) are required to produce a much smaller amount of animal protein. With the size of animal agriculture, most are not roaming around grazing grass, they are eating farmed plants [1]. Because it takes many plant calories (I've seen estimates from 10-25 plant calories for one calorie animal) animals are using way more land, fertilizer, transportation, no matter how much of the animal is being used [1] https://sentientmedia.org/u-s-farmed-animals-live-on-factory.. https://sentientmedia.org/u-s-farmed-animals-live-on-factory.... >According to the latest Sentience Institute analysis, the percent of U.S. farmed animals living on factory farms is… * Broiler chickens (99.9%) live on factory farms * Turkeys (99.8%) live on factory farms * Egg chickens (98.2%) live on factory farms * Pigs (98.3%) live on factory farms * Cows (70.4%) live on factory farms https://www.smithsonianmag.com/travel/is-the-livestock-industry-destroying-the-planet-11308007/ https://www.smithsonianmag.com/travel/is-the-livestock-indus... > A 212-page online report published by the United Nations Food and Agriculture Organization says 26 percent of the earth’s terrestrial surface is used for livestock grazing. One-third of the planet’s arable land is occupied by livestock feed crop cultivation.