WASHINGTON (Reuters) - An influential Democratic senator on Friday called for the Republican-controlled House of Representatives to vote on a new U.S. farm bill before the end of the year and thus avoid a potential spike in U.S. milk prices and other repercussions.

"Our rural economies will take a big hit if the House fails to pass a farm bill. Make no mistake, the farm bill is a jobs bill," Senator Max Baucus of Montana said during a Senate debate on Friday.

"There is absolutely no excuse for inaction. I call on the House to bring the Senate farm bill up for a vote immediately," said Baucus, chairman of the Senate Finance Committee.

The Senate passed a new five-year farm bill in June, and the House Agriculture Committee followed quickly in July, with its own version.

But the House bill, with large cuts in food stamp funding for lower-income Americans, has never been brought to a vote by the full House. The previous bill expired September 30.

U.S. milk prices at the grocery store could rise sharply in 2013, without a new bill or a specific patch to address dairy programs, because the government will have to revert to 1949 "permanent law" that requires USDA to buy milk at inflated prices.

It is unclear if the Senate or the House plans to act in the next few days, though.

"Our farmers and ranchers break their backs to put food on the table every day," said Baucus. "The least they deserve is an honest fair up-or-down vote on their jobs bill."

(Reporting By Doug Palmer; writing by Ros Krasny; Editing by Bob Burgdorfer)