The Agriculture Department said today that tests conducted on an animal that died in November, suspected of having mad cow disease, had turned out positive, confirming the second case of the disease to be found in the United States in the last two years. The tests for the brain-wasting disease, clinically known as bovine spongiform encephalopathy, were conducted at a laboratory in Weybridge, England, after officials at the United States Department of Agriculture were not satisfied with the results of previous tests on the same cow. These test results could raise fears that foreign countries will shun American beef again,...