GRASS-FED OR CORN-FED CATTLE?

 Meal conversion ratio is 8-10 to 1 for cattle, versus 4-5 for pigs, 3 for chickens, 1 for fish. The wonderful thing about cattle, though, is that it can be fattened on grass, thanks to their archaic digestive system. 

If corn is going to be transformed into meat at all (instead of being eaten directly, a feasible option for humans), using fish, chickens or pigs makes far more sense than using cattle.

Only a gross corn overproduction surplus allows it to be given to feeders, which can be fattened (to a healthier point) on grass, something humans cannot eat.