Washington ? Galloping to the aid of the nation’s wild horses and burros, the House voted Friday to rescue them from the possibility of a government-sponsored slaughter and give them millions more acres to roam.

But the effort may get penned up in the Senate.

The bill passed the House, 239-185, with Republican opponents arguing that it underscored wrongheaded Democratic priorities by focusing on animals instead of people at a time when the nation’s unemployment rate is approaching double digits.

An estimated 36,000 wild horses and burros live in 10 Western states. Federal officials estimate that’s about 9,400 more than can exist in balance with other rangeland resources. Off the range, more than 31,000 other wild horse and burros are cared for in corrals and pastures.

The plan aims to reduce the number of animals kept in holding pens awaiting adoption and to reduce the stress on land set aside for them.

Supporters mobilized after the Interior Department announced last year that it might have to kill thousands of healthy wild horses and burros to deal with the growing population on the range and in holding facilities.

Republicans dismissed the measure as welfare for horses, but Rep. Nick Rahall, D-W.Va., said a majority of Americans would not support slaughtering healthy animals or keeping them in holding pens for years at a time.

“The status quo is a national disgrace,” said Rahall, chairman of the Committee on Natural Resources. “It is a disgrace to our heritage.”

However, no comparable bill has been sponsored in the Senate, which doesn’t bode well for final passage of the measure. Both houses would have to approve the legislation before it could be sent to the White House for President Barack Obama’s consideration.

Some lawmakers from Western states said Congress is mismanaging the nation’s wild horse population by preventing the Bureau of Land Management from keeping populations at a level that’s appropriate for the environment. They said more horses will just make the problem worse.

The Congressional Budget Office estimated that enacting the Restore our American Mustangs Act would cost about $200 million over the next five years. Currently, the wild herds roam over about 33 million acres of Western land.

To comply with the bill, the Bureau of Land Management would need to find an additional 20 million acres, primarily after 2013, at a cost of up to $500 million, according the CBO. But Rahall said those estimates don’t reflect new language in the bill that makes adding millions of acres of rangeland a goal rather than a legal requirement.