epublican Rep. Paul S. Trible and Democratic Lt. Gov. Richard J. Davis worked a crowd numbering more than 12,000 here today at an open-air country fair celebrating a principal local industry--pig farming--that served as the kickoff of their campaigns for the U.S. Senate.

True to tradition, the politicians showed up in droves at the Emporia Pork Festival to curry votes, pump hands and plaster the fair with hundreds of campaign lapel stickers.

"If you use these stickers as the gauge, I think I'm ahead by 10 percent," beamed an ebullient Trible.

For Davis, the soft-spoken millionaire mortgage banker from Portsmouth, the pork festival had special meaning. For his first public appearance since capturing the Democratic nomination on Saturday, he has journeyed to the heart of conservative Byrd country. It was thus the ideal setting to counter Trible's most serious charge yet: that he is a liberal.

"I resent that," Davis said. "The most conservative trade association in America is the mortgage bankers association and they've nominated me to be their next president . . . If we're going to use those terms, I'm going to call him a reactionary."

Trible refused to rise to the bait. Trailing Davis by about 100 yards on the 12-acre fairground, he repeated the same answers to a host of reporters' questions. "I really don't know where my opponent stands on the issues--national defense, foreign policy," he said. "I look forward to the opportunity to find out."

For all the campaigning, most spectators seemed more amused than excited. "Nobody cares about politics in June," sighed Del. Alson Smith of Winchester, a loyal Democrat and Davis backer. "It's just something you've got to do."