The bulk of the food cows are eating is unfit for human consumption. You couldn't feed it to people even if you wanted to. Our digestive system is completely different and can't be "upgraded" to work like that of a cow.
Calories are not all equals, otherwise we could just feast on corn sugar all day and be healthy.
If you want to be a vegan because you feel sad thinking about animals being slaughtered or because you have a craving for foliage, knock yourself out, but stop peddling that bullshit that's been around since the hippies.
Our digestive system can't digest corn and soy? That's what cows are fed in industrial agriculture. Get your facts straight and ease back on your venomous hate.
Most of their diet is grass while in pasture, hay over the winter, and grain when fattening them up for slaughter. Grass and corn grow very well with little help beyond planting and limited watering...the cows get most of that water from eating grass in their pasture and drinking from ponds in the pasture.
This is a romantic view of how cows are reared. The cows in our food chains are in fact fed almost entirely on corn and soy, and they don't have any pasture or ponds to drink from. Animal agriculture is in fact an industrial commodity produced using factory farming methods. The water problem lies in the fact that it takes all the fresh water that a cow drinks, plus all the water used to irrigate the 10-40 pounds of feed (for each pound of meat), plus the loss of fresh water in the supply that is polluted with their sewage. The EPA themselves estimate that 2,500 head of cattle produce the same amount of raw sewage as 411,000 people.
Recent investments will yield a slight profit.