Cows mostly. Like 60-75% of all ag land in the US is to grow feed for cows. Mostly in dry environments. This is because the old water rights were distributed o

Cows mostly. Like 60-75% of all ag land in the US is to grow feed for cows. Mostly in dry environments. This is because the old water rights were distributed on a "use it or lose it" basis which encourages wasteful use.