BILLINGS, Mont. — U.S. Agriculture Secretary Mike Johanns said yesterday it could be just days before the first shipment of U.S. beef in two years is on its way to Japan.

Johanns, who spoke to a convention of farmers and ranchers here, told reporters that he was optimistic about the prospect of beef trade resuming with Japan for the first time since a case of mad cow disease was discovered in this country in December 2003. Japan's Food Safety Commission yesterday said U.S. beef was as safe as that country's, a move that could clear the way for the Japanese government to at least partially lift the ban on U.S. beef shipments and allow in meat from younger animals.

"I said to people, 'The smile on my face, there's a good reason for it,' " he said.

Johanns said the process, while long, has been moving toward the resumption of beef trade though he didn't know for sure when the Japanese government would make that final decision.

"Now, I wish I could tell you that the bell will ring at noon on Monday or noon on Tuesday, or noon today," he said. "But the reality is, that we are really to a point where I think we're in the final piece of this."

The United States also is moving toward easing its ban on beef from Japan, Johanns said. Japan has reported 20 cases of mad cow disease, according to the U.S. Department of Agriculture.

"We've done our homework, we've done our analysis, and we'll be ready to go," Johanns said, noting the beef would be subject to certain restrictions. "Now, whether it will be absolutely, exactly simultaneous, that's something that today I just wouldn't commit to, in terms of giving you a time line for that, either."

Japan is looking at limiting U.S. beef shipments to products from cattle younger than 21 months, a cutoff that some agricultural leaders have said has no scientific basis. Still, Johanns said he would welcome even the more limited resumption of trade as a positive step and believed the U.S. cattle industry would also be encouraged by it, and adapt to it.

"We know U.S. beef is safe. They have found it is safe. But we have to work with consumers. We need to take the case to them now," Johanns said, noting that the United States would be pressing for fuller trade.

Steve Pilcher, executive vice president of the Montana Stockgrowers Association, said the resumption of beef trade with Japan would be significant, both as a morale booster and an opportunity to again get into what had been a prized, lucrative export market.