Mad cow disease is believed to have spread from Britain to other countries when the bones and other remains of diseased cattle were ground up for use in livestock feed.
Mad cow disease is believed to have spread from Britain to other countries when the bones and other remains of diseased cattle were ground up for use in livestock feed.
由于病牛的骸骨和病牛的残骸成为生物饲料中的主要构成成分，疯牛病被认为已经从英国蔓延到其他国家。