Conrad Burns, a former Montana livestock auctioneer who was catapulted from county commissioner to the United States Senate, where he was known for speaking plainly and for sometimes making derogatory remarks, died on Thursday at his home in Billings, Mont. He was 81.

His death was confirmed by Mark Baker, his former staff director and counsel in the Senate.

Mr. Burns served three terms in the Senate, where he worked on telecommunications legislation, focusing on access in rural areas, and influenced policies on energy and federal land management.

He went to the Senate after serving just two years as a commissioner in Yellowstone County, defeating an incumbent Democratic senator, John Melcher, in 1988. In 1994, Mr. Burns became the first Republican senator in Montana history to be re-elected.