As if Congress hasn't failed enough this year to ingratiate itself with the public, the price of a gallon of milk is at risk of doubling in early 2014 if lawmakers don't pass a long-delayed farm bill by year's end.

The 2008 farm bill expired last year without a replacement, though coverage for most Agriculture-related federal subsidy programs have been extended through 2013. But if a new farm bill isn't enacted by January, or at least gets a short-term fix, the federal Agriculture Department will end its current dairy price support program, ushering in higher prices for a gallon of milk.

If that happens, a gallon of milk likely would cost between $6 and $7, estimates the National Sustainable Agriculture Coalition, an alliance of grass-roots organizations that advocates for federal policy reform.

The House and Senate have passed competing farm bills, and negotiators have been meeting for weeks to hammer out a compromise. But with the two sides far apart, a new deal isn't expected to be done by Jan. 1.

House Speaker John Boehner, R-Ohio, on Thursday told reporters he hasn't seen "any real progress" regarding the farm bill talks and said he's prepared to offer a one-month extension.

Milk prices wouldn't rise immediately, as the Agriculture Department would have to write new rules before enacting them. But Agriculture Secretary Tom Vilsack has warned that it may not take long, saying his department was prepared to implement the new dairy law in "short order" if current law expires.

"Boy, I tell you, that's not something that I want to do," Vilsack said. "I'm reasonably certain that's not anything that anybody in Congress would want to have happen, and I'm sure that no consumer is anxious to see that happen. So hopefully we continue to see progress."

But a short-term extension isn't certain, as Senate Majority Leader Harry Reid, D-Nev., has said he doesn't want to extend the bill again after Congress already extended the bill at the beginning of this year.

While the milk subsidy program isn't controversial and is supported by lawmakers from both parties, other farm bill-related items -- particularly the Supplemental Nutrition Assistance Program, commonly called the food stamp program -- has stalled passage of a long-term farm since last year.

The Associated Press contributed to this article.