@itsveganjim Leaving aside the animal aspect and just focusing on the "efficiency" for a second - meat (and less for dairy) makes absolutely no sense from an economics standpoint.

60% of the US arable land grows feed for animals (domestic or export). Another 25% grows corn for ethanol for cars. Using this land for human crops would feed close to another billion people.

1 acre of corn feeds 70 ppl for a year. Or it feeds half a cow which feeds those 70 ppl for ... about a month.