WASHINGTON — Agriculture Secretary Tom Vilsack on Friday urged the Republican-led House to vote on a longterm farm policy bill, saying failure to act could leave livestock producers exposed to disasters and other farmers uncertain about the future.

Vilsack, in an interview with The Associated Press, dismissed apparent concerns among House GOP leaders that the half-trillion-dollar farm and food bill could lead to an election-year rebellion among conservatives. “If they put it up on the board, there would be enough votes,” he said.

“It just needs to get done and there’s no excuse for it not to be done,” he said.

The former Iowa governor said he was particularly concerned about livestock producers now coping with fires in the West and drought in the Midwest. Federal livestock disaster programs ended last September and would not be renewed if the current farm bill, which expires Sept. 30, is extended because Congress is unable to pass a new bill.

The Senate last week voted 64-35 to pass a five-year bill. It ends direct payments to farmers regardless of whether they plant crops, sets up new crop support programs and reduces the federal deficit by $23 billion over the next 10 years.

Obstacles to passage are greater in the House, where conservatives are seeking deeper cuts in the federal food stamp program, which makes up about 80 percent of the nearly $100-billion-a-year spending under the legislation. The Senate bill targets $4 billion in savings from the expected $770 billion in food stamp costs over the next decade.

The chairman of the House Agriculture Committee told the AgriTalk radio show on Thursday that the House’s farm bill, which has yet to be introduced, would probably look for $14 billion or $15 billion in food stamp savings. Rep. Frank Lucas, R-Okla., aid the entire bill would reduce spending by about $30 billion.

Lucas has scheduled a committee vote on a farm bill for July 11, and said once the committee has acted, he will ask Republican leaders for floor time. “I don’t care if it’s 8 in the morning or if it’s 3 in the afternoon, or if it’s 10 minutes till midnight, just give me time.”

GOP leaders have not ruled out action on a farm bill, but have indicated they want to devote much of the House’s time to jobs and regulatory bills that draw a contrast with Obama administration policies and with 2013 spending bills.

Vilsack said he was confident that Lucas and the top Democrat on the committee, Rep. Collin Peterson of Minnesota, were committed to getting a bill passed. “I want to strengthen their hand as they deal with House leadership,” Vilsack said.

The secretary said that without a new farm bill in place, farmers would be unable to make decisions about future production, there would be a lack of clarity about trade promotion programs and uncertainty about conservation programs. He said the farm bill could become a part of expected yearend talks on how to handle expiring tax cuts and automatic cuts in defense and domestic programs, resulting in deeper reductions to farm programs.