WASHINGTON -- The Bush administration is urging a federal appeals court to keep meatpackers from testing all their cattle for mad cow disease.

Government lawyers told a three-judge panel today that hey should reverse a lower court ruling that allowed Kansas-based Creekstone Farms Premium Beef to conduct more comprehensive testing to satisfy overseas customers.

The Agriculture Department currently tests less than 1 percent of slaughtered cows for the disease. It argues that more widespread testing does not guarantee food safety and could result in a false positive that scares consumers.

Creekstone claims the Agriculture Department has no authority to prevent companies from using the test to reassure customers.