` ` They 're not looking very hard for mad cow disease , '' says one of USDA . South Korea is the second - largest producer of beef from the United States . In people , symptoms of mad cow disease include psychiatric and behavioral problems .
`` They 're not looking very hard for mad cow disease , '' says critic of USDA . South Korea is the second-largest importer of beef from the United States . In people , symptoms of mad cow disease include psychiatric and behavioral changes .