USDA quarantines 2 farms in mad cow investigation

Two farms have been quarantined by the U.S. Department of Agriculture as the agency continues to investigate last month's discovery of mad cow disease at a California dairy farm. Authorities also have launched an investigation at a calf ranch where the initial infected cow was raised 10 years ago, according to a statement released late Wednesday by the USDA. The farm where the cow was initially discovered has been under quarantine since the discovery, agriculture officials said. Wednesday's announcement of a second quarantine involves a farm closely associated with the dairy where the sick cow was discovered last month, the USDA said. The agency is still trying to determine if any at-risk cattle are present at either of the two farms. (more) May 3, 2012 CNN