WASHINGTON - The Treasury Department, trying to block an elaborate money-laundering scheme, has announced that two Mexican cattle companies are fronts for drug-trafficking cartels. The action means that cattle sold by the companies to Texas ranchers after Friday's announcement are subject to seizure by the federal government, said a high-ranking Treasury official who asked not to be named. "Cattle already purchased and owned before the companies were identified as tied to the drug cartels are not going to suddenly be blocked," the official said. The Treasury Department plans to inform cattle associations and other groups later this week of the...