Here is an interesting tidbit.
"According to previous research, it takes 226 more days for grass-finished cattle to reach market
weight than grain-finished cattle. More days on grass may mean greater environmental impact. For
example, compared to grass-fed beef, grain-fed beef uses 76 percent less water."
http://www.explorebeef.org/cmdocs/explorebeef/fact_sheet_beef%20and%20water%20use.pdf
Looks like industry propaganda. Farmers don't water their pastures so it must count rainwater. I think most agree that man-made irrigation has a different impact than rain. Also it probably doesn't take into account best practices of well managed small farms: they are rotating their herd on pastures and not applying chemicals. Factory farming relies on growing corn and soy with huge amounts of fertilizer, herbicides, and pesticides, clean cutting the fields leaving bare earth, then trucking that to feed lots where the cattle get antibiotics to counter act diseases caused by eating grains which they are not evolved to do and living in their own filth.
In my part of the country, corn and soybeans are what they call "dry farmed" in the west, i.e. no irrigation.
Factory farms are not pretty. I agree on that.
Edit - this was about the water usage of beer.
That's good anyway. Factory Farming is one of the few things I can get really pissed about so sorry if this all seemed a bit charged. Its just that its lose-lose-lose for everyone but the handful of big companies that make a killing. The animals are treated cruelly, the ones doing the actual work are treated poorly, its an environmental disaster, and the end product is, while cheap, unhealthy tasteless crap. And the cheap price isn't the real cost: its paid for by taxpayer's subsidies on corn and soybeans.