This is a very interesting battle:

The Bush administration on Friday urged a federal appeals court to stop meatpackers from testing all their animals for mad cow disease, but a skeptical judge questioned whether the government has that authority. The government seeks to reverse a lower court ruling that allowed Kansas-based Creekstone Farms Premium Beef to conduct more comprehensive testing to satisfy demand from overseas customers in Japan and elsewhere.

But Creekstone attorney Russell Frye contended the Agriculture Department's regulations covering the treatment of domestic animals contain no prohibition against an individual company testing for mad cow disease, since the test is conducted only after a cow is slaughtered. He said the agency has no authority to prevent companies from using the test to reassure customers.

Larger meatpackers have opposed Creekstone's push to allow wider testing out of fear that consumer pressure would force them to begin testing all animals too. Increased testing would raise the price of meat by a few cents per pound....read on