As farmers bear the brunt of historic water shortages in California and the wider south-western United States, the US industry publication Beef Magazine takes stock of recent studies on water usage in the beef sector.

According to US livestock columnist Steve Kay, "research reveals that it takes 226 more days for grass-finished cattle to reach market weight than grain-finished cattle. Compared to grass-fed beef, grain-fed beef uses 76% less water".

Kay also quotes from a study published in 2011 in the Journal of Animal Science, showing that the amount of water used to raise beef has dropped 12% in 30 years.

Another study by the University of California-Davis says it takes just 441 gallons of water to produce one pound of boneless beef. By comparison, more than 713 gallons of water go into the production of one cotton T-shirt.

Kay argues that while the US beef industry remains a large water user, it is getting better at managing this resource more efficiently.

Rain and grass boon for Ireland

While energy resources and cost have dominated the global debate, drought in the developed world reminds us just how big an issue water is. Beef production is typically highlighted as a luxury use of this precious resource that society will have to give up.

In many parts of the world that is true, but for countries like Ireland with high rainfall and a temperate climate, grass is often the only crop we can successfully grow - and converting this to beef and milk is the only way that this grass can be converted to a food that humans can utilise.