Mad Cow: 2003 versus 2012 What a difference a decade makes. The discovery of a BSE-infected dairy cow in California, the fourth case in the U.S., this week is having relatively minimal impact compared to the 2003 case in the state of Washington. In 2004 the U.S. began its enhanced surveillance program for mad cow disease. Now, nine years later, the markets have worked their way through the shock and anxiety phases. There were 29 cases of mad cow disease found worldwide in 2011, down from more than 37,000 in the 1990s. The most recent discovery of BSE in the U.S. was an "atypical" case, with modified prions indicating that contaminated feed was not the source. The good news is top customers Canada, Japan and Mexico have given assurances...