The U.S. government announced rules intended to prevent outbreaks of mad cow disease in American cattle herds. No cases of Bovine spongiform encephalopathy (the scientific name for mad cow disease) have ever been detected in U. S. herds.

• 美国政府公布了旨在防治疯牛病在美国牛群中爆发的细则。美国的牛群中至今尚未发现牛海绵状组织脑炎(疯牛病的学名)病例