If you're feeding beef irrigated feed, that's crazy.

But normally beef are fed crops that are highly drought resistant, like grass, alfalfa and barley.

Human crops like wheat, rice and corn require a lot more water than feed crops.

So if your rainfall levels are less than what is required by human food crops, you have several options:

- irrigate - grow cattle feed without irrigation - idle the land

The 3rd option may be the most environmentally friendly, but it doesn't feed anybody.

Beef may require more water per calorie than other foods, but it may still be more efficient. It doesn't really matter how much water is required -- it matters how much irrigation is required. And for beef, that number can be "0" in areas where nothing else is.