Two days' drive from the Mongolian capital of Ulaanbaatar, 100 miles from the country's border with China, the foothills of the Altai Mountains slash a jagged brown line across the scrubby southern Gobi grasslands. Home to hungry wolves and snow leopards and brutal winters, it is rough country for herders such as 57-year-old Otgonbayar, a weather-beaten nomad who works his flock of 1,000-odd cashmere goats and two dozen sheep from the back of a 100-cc Chinese motorcycle.