Inside the Interior Department, they refer to it as "the cow pie case." And frankly, they think it stinks.

But if the agency loses a case that a federal judge has ordered to trial, it soon may have to determine whether flatulent sheep, cattle and buffalo are contributing to global warming.The Washington-based Foundation on Economic Trends filed a lawsuit last year accusing the federal Agriculture, Interior and Energy departments of failing to measure how much flatulent livestock are contributing to global warming by pumping methane gas into the atmosphere.

"It is basically known as the cow pie case," said the Interior Department's top lawyer, Tom Sansonetti.

Sansonetti is taking the fragrant fracas seriously, especially after losing an early round in court. He has assigned a lawyer to the case full-time.

"We filed a motion to dismiss . . . and we lost. It's going to go to full trial on this issue," he told the Wyoming Stock Growers Association and Wyoming Wool Growers Association on Friday. "I couldn't believe it."

The foundation alleges that flatulent livestock could be producing up to 15 percent of atmospheric methane, believed by some scientists to be a contributing factor to global warming.

Scientists believe global warming, also known as the greenhouse effect, occurs when the layer of carbon dioxide and other gases accumulating above the Earth prevents the atmosphere from cooling. Scientists say it can lead to potentially catastrophic climate changes that can cause polar ice melting, a rise in the world's oceans and drought conditions.

If the foundation's lawsuit is successful, Sansonetti said the Interior Department's Bureau of Land Management would have to determine how much methane is generated by livestock grazing on public lands.

If a study is undertaken and it finds that the animals are indeed releasing too much methane, Sansonetti said farmers might be asked to "produce less windy cattle."

One way to do that, he said in an interview, would be to change the animals' feed.

Another alternative would be to reduce the number of animals allowed to graze on public land.