(CNN) -- Jersey, Guernsey, Holstein; the world's dairy cattle breeds bear the names of some of the wettest, lushest, and greenest places in Europe, testament to the fact that to produce milk you need a lot of water. Industry experts say one cow must consume three liters of water a day to produce one liter of milk. For high-performing cattle that's equal to 150 liters a day. Saudi Arabia --with an average annual rainfall of just 2.3 inches (59mm) -- might seem an unlikely candidate to be among the world's top 10 dairy producers, but its mega-dairy Almarai has grown to be one of the biggest food producers in the Persian Gulf.
@highlight
Saudi Arabian dairy has become one of the biggest in the region
@highlight
Almarai began as a small farm in 1970s with 300 cows
@highlight
Situated in one of world's most arid regions, indoor farms rely on 'California model'
@highlight
Critics point to high use of water and depletion of ancient underground water reserves
Persian Gulf
Almarai's fleet of 1,000 refrigerated tankers then deliver it to 55,000 stores in six @placeholder nations.
Persian Gulf
However, critics warn that the high yields of Almarai and other @placeholder dairies carry a cost.