The U.S. government has the authority to bar meat companies from testing their animals for mad cow disease, a federal appeals court has ruled.  The Department of Agriculture’s failure to test more than a fraction of cows for the brain-wasting disease prompted one meat company to announce that it would test all of its bovines, the Associated Press reported.  But the government turned thumbs down on that request, from Kansas meat producer Creekstone Farms. Bigger meat packers feared the move would force them to employ the costly test on all of their cows, as well, the wire service said.  The U.S. Court of Appeals for the District of Columbia, in overturning a lower court ruling, upheld the government’s right to prevent Creekstone from testing its cows, the AP said.