It's tough being a dairy cow in the middle of the Arabian desert, so any perks are welcome. Especially air-conditioning.

Outside the temperature hits 44 degrees Celsius (110 degrees Fahrenheit), but under the 600-metre (yard) long shelter, dozens of "desert coolers" make life a little more tolerable.

"Forty-four degrees? That's quite cool for the summer," said Amr Ateia, one of 1,400 staff at the sprawling Al Safi farm 100 km (60 miles) southeast of Riyadh.

Set in unpromising territory, Al Safi has defied the elements to grow into the world's biggest integrated dairy farm - where thousands of litres of milk are produced and packaged every day.

"The challenges here start with the environment. It's arid, harsh and hot," said Ziyad al-Mirzam, acting farm manager. "The other challenge is finding water."

The desert coolers deal with the heat, while six wells sunk 1,850 metres (6,070 feet) below the desert sands pump up hot water for cleaning and drinking.

Each cow drinks up to 120 litres (26 gallons) a day and the farm as a whole consumes precious water on an industrial scale - 10 million litres daily in summer.

Feeding the herd is a further challenge. Another desert farm 200 km (125 miles) away, irrigated by water from aquifers deep underground, supplies hay and grass.

HEAT STRESS

Mirzam said that during severe heat waves, which can last from three days to a couple of weeks, cattle "feel stressed" and are reluctant to walk the short distance to their food.

"But they're the best creatures - they never complain or ask for a salary rise," he said.

In fact the 32,000-strong herd of black and white Holstein-Friesian cows, first imported from Europe and the United States 20 years ago, have thrived on land which before Saudi Arabia's oil boom was home only to camels and nomadic bedouin tribes people.

Russell Wards, a former New Zealand dairy farmer who has worked at Al Safi for 15 years, said the cooling systems meant conditions were no worse than the hot, dry states in America.

The desert climate even has one advantage.

"With the dry environment, it's probably an easier life for them here," he said. "Once we solved the cooling problem, we don't have the disease problem caused by the wet conditions in some parts of the United States."

Saudi Arabia, which spent billions of dollars subsidising domestic agriculture in the 1980s and 1990s, ended up with an wheat surplus which critics said had cost it dearly both in money and scarce water resources.

Mirzam said Al Safi was a profitable private business without government support. But he conceded there was a risk that it was depleting the kingdom's water reserves. "There is a risk in any type of operation like this," he said.

Everything at the farm, which produces 165 million litres (36 million gallons) of milk a year, is geared to maximise output.

In one of the milking parlours 120 cattle are milked by machine in 10 minutes - another record, the farm says - before they make their way along a shaded corridor back to the shed.

But the comfort comes at a price. Most cows produce an average of 35 litres (7.6 gallons) of milk a day, and monitors around their necks ensure that every drop is measured and recorded.