Shannon Dininny, Associated Press
The Circle-V brand can be seen at Craig Vejraska's cattle ranch in Omak, Wash. on June 17, 2011.

SAN JOSE, Calif. — One of the West's most enduring symbols is fading like a red-hot branding iron cools to ashen gray.

With concerns over disease and global trade trumping tradition, federal regulators want ranchers to swap the old-fashioned cattle brand for electronic ear tags to quickly and reliably identify livestock.

Ranchers accept the inevitability but lament the passing of a ritual older than America — the smell of trampled sagebrush and burned hide, the sound of whinnying horses, songs around campfires and friendly boasts among friends.

"Cowboys are said to ride for the brand. It's hard to imagine anyone riding for an ear tag," said Jon Christensen, executive director of the Bill Lane Center for the American West at Stanford University.

The debate over the USDA proposal, with a final rule expected within months, "is not just a fight over the best way to identify, track and ensure the ownership and safety of cattle," said Christensen. "This is a battle over a powerful western icon."

But the discovery in late 2003 of a cow in rural Washington infected with mad cow disease inspired federal officials to find a better way to instantly track livestock. They feared that the U.S. could suffer the same fate as the United Kingdom, which quarantined and killed tens of thousands of animals after a foot-and-mouth disease outbreak, devastating its agricultural economy.

The USDA wants every cow to have a unique numerical ID, electronically embedded into an RFID ear tag, to make it easier to track animals from the ranch to feedlots and the slaughterhouse. Then, if a sick animal is found, the source of illness could be found — and isolated — within hours.

And lucrative global markets, like Japan, are now demanding that meat be proven safe and "traceable" before entering the country.

Once every cow has an RFID tag, the brand — as a vital identification mark — would become less critical.

"I see brands playing a smaller role as we move into this electronic age," said longtime Monterey County-based rancher Jim Warren, 70, a pioneer in early adoption of radio-tagging for 1,000 Central California cattle producers who sell through his 101 Livestock Inc. auction barn.

"We have to be forward thinking," said Warren, over a lunch of chili before Tuesday afternoon's busy bidding in the small town of Aromas. "Branding still has its place — it's a means to identify cattle within a state. But we are a global economy. We no longer have the luxury of saying we will only do business within our own borders."

Hot-iron brands have played an enduring and beloved role — they're family logos, like a ranching coat of arms — ever since they were introduced to the New World in 1541 by Spanish conquistador Hernan Cortes, whose cattle were singed with three crosses.

They landed in history books, films and TV shows after the great Longhorn trail drives out of Texas during the 1800s.

But with growing awareness of animal rights, critics have denounced the practice as cruel.

Still, no 15-character alphanumeric identification code can ever replace a "Lazy J," "Hanging R" or "Flying 45," said Bill Bullard of the Billings, Mont.-based Ranchers-Cattlemen Action Legal Fund, United Stockgrowers of America.

"The government is giving in to international pressure to adopt a one-size-fits-all system that replaces the American tradition of branding, which has been used for centuries successfully," he said.

Branding is the simplest and most efficient way to identify a cow, he said. He worries that cattle could lose their tags in fencing or trees. Rustlers could easily cut them off. And the cost of the RFID tag — $2 to $3 per animal — could add new economic hardship to small family ranchers, he said.

Facing outrage from cattle producers, the Obama administration ultimately scrapped an ambitious plan to track all livestock every time it was transported from birth to the slaughterhouse.

The new proposal is less sweeping because it applies only to animals being moved between states.