Farmers and ranchers will not be forced to register their cows, pigs and chickens in a nationwide database aimed at helping track the outbreak of disease, the Bush administration said Wednesday. Hoping to dampen widespread opposition to the animal tracking program, the Agriculture Department has decided it should remain voluntary. "Really embracing this as a voluntary program ... will help the trust issues that some farmers and ranchers have raised about the national animal identification system," said Bruce Knight, Agriculture undersecretary for marketing and regulation. "I'm certainly hoping to move beyond some of the very emotional debates on animal ID," Knight told The Associated Press in an interview. First promised in response to the discovery of mad cow disease in this country, the tracking system would pinpoint an animal's movements within 48 hours after a disease is discovered.