 There are few things more Texan than a cowboy. But now, in the teeth of the worst drought that the Lone Star State can remember, cattlemen are leaving in droves. This year, Texas endured one hell of a summer - the hottest and driest on record. "There's been days when it's been 114 degrees [45.5C], with a 30mph wind," said Dennis Braden, the general manager of the Swenson Land &amp; Cattle Co, a ranch that has reared cattle since the 1850s. "Imagine a blow dryer in your face; I ain't never seen a summer like it." When there was no rain last winter, the ranchers sat tight for the spring deluge. When that failed, they started getting nervous. after the summer showed no respite, the Swenson ranch moved its cattle north, out of Texas for the first time. Last month more than 1,000 Black angus and Herefords were taken by rail to leased pastures in West Nebraska and Wyoming. "How long are they going to stay there? I don't have a clue," said Mr Braden.  In previous droughts, ranchers would have sold their h 