It may sound like a chapter out of the American Wild West, but Australian farmers say an explosion in cattle rustling is costing them millions of dollars a year. In a modern twist on a crime romanticised by artists and bush poets since the 19th century, today's rustlers use helicopters, light aircraft and motorcycles to round up thousands of cattle and sheep on remote Outback properties. In some cases rustlers - or 'duffers' as they are known in Australia - have stolen more than A$100,000 (HK$400,000) worth of livestock in one night, threatening owners with bankruptcy. Last year livestock theft amounted to A$2.3 million in New South Wales alone. Authorities say a lot more goes unreported. 'Farmers are losing thousands of dollars. It's a major problem,' said Sarah Dent, spokeswoman for the National Farmers' Federation. The recent upsurge in rustling has been driven by the high price of beef, with a calf now fetching around A$600, compared with A$300 three years ago. The value of sheep has also increased, with lambs selling for A$80 each - double their value a few years ago. 'Prices are good for all stock at the moment because of the weak Australian dollar and rising demand in our main export markets, the United States and Asia,' Michael Hartmann, deputy director of the Cattle Council of Australia, said. When farmer Peter Groegor checked his cattle herd on Boxing Day he found 130 animals had been stolen, taking the value of his losses in the past 14 months to A$300,000. Over the past two years theft has reduced his herd from 400 animals to just 96. 'I'm devastated, it's sending me broke,' he said. 'I've given up running cattle on my property because thieves would have stolen them all.' He has had to move his remaining livestock to a secret location 500km away. Professional teams of cattle thieves roam the Outback looking for likely targets. After rounding up the cattle or sheep with men on motorcycles and sheep dogs, they set up portable stockyards and load the animals into trucks. From there they are given new brands and ear tags and sold to abattoirs or at livestock markets, with no questions asked. Farmers say police are not doing enough to track down the criminals, with conviction rates as low as two per cent. But the police point to the enormous distances involved, and the fact that in many cases it is only months later that farmers come to muster their herds, that they realise their animals have been stolen. Farmers now hope that modern technology may succeed where traditional policing has failed. There are plans for a national livestock identification scheme, under which all cattle and sheep would have a microchip implanted in their stomach. Before being sold at market they would be led past an electronic scanner which would beep if they had been reported stolen.