Federal policy is meeting Western reality on the rangelands of Idaho, where wide-open spaces, technological glitches and bitter cold all are potential obstacles to plans to track livestock and protect the food supply from disease and bioterrorism.

 The U.S. Department of Agriculture is trying to create a national network that would track, within 48 hours, every contact an infected animal has had in its life. The USDA says such tracking is necessary because it took only a single Holstein infected with mad cow disease last year to lead more than 30 countries to close their borders to U.S. beef.

As envisioned in Washington, D.C., the tracking network would cover not only cattle, but horses, poultry, bison, sheep, hogs and farmed fish. Farmers with a couple of milk cows would participate alongside ranchers with thousands of cattle. Even kids who raise and exhibit an animal as a 4-H project would be part of the network.

One of the chief ideas under consideration would involve electronic tags on animals' ears. USDA is funding testing of the technology in Idaho and other states. Industry analysts believe some type of mandatory national tracking system will be in place in three or four years.

But the vast scope of Western ranching is a problem in itself. Large herds mingle on thousands of square miles of public range for weeks or months on end. That could make it extremely difficult to tell which cattle a particular infected animal might have come in contact with and when.

Also, some ranchers' grazing allotments cross state lines, and some herds graze on both public and private land. That could greatly complicate the paperwork ranchers would have to fill out as part of the tracking network to show where their animals have been grazing.

"It's good that we're getting this started now, because there's going to be glitches," said Jim England, a University of Idaho veterinarian.

England, who was testing some tracking technology at a livestock sales yard in Emmett, found more practical problems. Trying to read electronic ID tags attached to the ears of calves, he discovered that the wand-like tag reader worked only within a foot of the tag. That could make it difficult to record large numbers of bunched-together animals; they might have to be sent through a chute one by one.

The tag reader is supposed to feed its data into a personal digital assistant, or Palm Pilot. But one electronic tag reader would not work in zero-degree weather, a not-uncommon occurrence on the range in some northern states. And England said the screen of his Palm Pilot shattered in the cold.

Julie Morrison, a cattle industry representative who is overseeing some of the testing, acknowledged the system won't come easily.

"We have a lot of cattle changing hands and moving around the region on any given day," she said. "I don't doubt the tracking technology is out there. But the bigger challenge is getting it up and running."

USDA spokeswoman Andrea McNally said the government has left it up to the industry to find what technology works best.

"We're technology-neutral," she said. "There's a bunch of different things out there. We want industry to use what's best for them. We just want it to be compatible with the national database."

On Thursday, USDA officials said a second case of mad cow disease may have turned up. They released few details and said conclusive tests could take four to seven days. If the system were in place now, government officials could track every cow that animal had contact with before the diagnostic tests were even finished.

Many ranchers seem reconciled to the idea of national tracking.

"It's something everybody knows they need to address," said Guy Colyer, owner of Colyer Herefords in Bruneau, a small town about 50 miles southeast of Boise. "It's going to be a complicated situation for most producers, but with the electronic system they're developing it's not going to be impossible. It's another tool to give the consumer more confidence that their beef is as safe as can possibly be."

Still, the notion offends some ranchers who hold dear the frontier ideal of independence and freedom from government control.

  Glenn Elzinga, the owner of Alderspring Ranch in Tendoy, is raising 440 cattle that are hormone- and antibiotic-free and are raised only on grass, grain and pasture, not commercial feed, which in other countries has been a source of mad cow disease.

"A national ID system is an unnecessary cost in a nation where most consumers don't even care," he said. "Most people aren't even concerned about the country of origin."