Mad Cow Discovery? Chalk It Up to Pure Luck Infected cow showed no signs of the disease By Kate Seamons, Newser Staff Posted Apr 25, 2012 9:31 AM CDT 6 comments Comments Beef and dairy cows, not the mad cow one. (AP Photo/Jessica Hill) (Newser) – This may not help you sleep better tonight. The discovery of mad cow disease in California was the result of ... luck, reports the AP. It explains that the state's dead cows are transported to a central California facility, where a very small number of the carcasses are tested. Officials say the cow presented no indication that it may have had the disease: unsteadiness, lack of coordination, behavioral changes, or low milk production. But because it arrived soon after death and was more than 30 months old, it was eligible for USDA testing. "We randomly pick a number of samples throughout the year, and this just happened to be one that we randomly sampled," says the facility's VP, who echoed the fact that "it showed no signs." Samples were sent to UC Davis' food safety lab on April 18. Officials announced yesterday that the cow had atypical bovine spongiform encephalopathy, meaning it didn't contract the disease from what it ate, but from a random mutation. It's unclear whether this rare type of BSE ever has been transmitted from a cow to a human by eating meat. Still, some major South Korea stores are halting sales of US beef.