The regulations, which were laid out as proposals in August 2011, had their genesis in the handful of cases of mad cow disease, or bovine spongiform encephalopathy, in the United States dating back to 2003.

USDA's initial proposals were attacked by farmers and ranchers as burdensome and too expensive.

Under the final rule, unless specifically exempted, livestock moved across state lines would have to be officially identified and accompanied by an interstate certificate of veterinary inspection or other documentation, such as owner-shipper statements or brand certificates.

"The United States now has a flexible, effective animal disease traceability system for livestock moving interstate, without undue burdens for ranchers and U.S. livestock businesses," USDA Secretary Tom Vilsack said.

USDA made some changes to its original plan after receiving more than 1,600 comments from a wide variety of stakeholders on its proposals between August and December.

A coalition of more than a dozen organizations argued that the rules would cost the U.S. cattle industry more than $1 billion a year.

Vilsack told reporters on a conference call that the final plan contains specific exemptions for certain classes of animals and types of interstate movements.

"It doesn't require a specific identification tag or dictate a particular format for record keeping," he said.

Also excluded are most beef cattle under 18 months, unless they are moved interstate for shows, exhibitions, rodeos, or recreational events.

Animal disease traceability, or knowing where diseased and at-risk animals are located and where they have been, is seen by USDA as part of a safety net to ensure a rapid response to outbreaks of animal disease.

"It's going to help us move quickly to identify where diseased and at-risk animals are, as well as which animals do not need to be held or tested during a disease investigation," Vilsack said. "That will help to protect the integrity of our markets during an animal disease situation."

USDA's final rules will be published on December 28.

(Reporting By Ros Krasny; Editing by Peter Galloway and Andrew Hay)

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