Is US Gov't covering up Mad Cow disaster?

I've been reading about the newest incident of mad cow disease in the United States. What's odd about it is that two days ago, the USDA was pushing to open imports of Canadian beef after they'd been cut off from the first incident of mad cow disease. That's after the initial tests showed positive for mad cow in the second case. Now I'm reading that they're testing suspected cases over and over and over again, totally unwilling to accept the fact that we might have a problem.

Considering the fact that Washington and Co. are totally in the pocket of big business, and the beef industry is as big as any other, could the government be covering up the extent of mad cow disease problems in the United States?

Since only a percentage of downer cows are tested to determine if they're infected, and NO non-downer cows are tested that I'm aware of, I'm somewhat concerned that this problem is a whole lot bigger than the government wants us to know.