WASHINGTON (AP) - The House directed the Interior Department on Thursday to halt the sale of wild horses for slaughter, saying that was not the purpose of the program that makes the horses and burros available for adoption.

The measure, part of the department's spending bill for the 2007 budget year, prohibits the use of agency funds for the sale or slaughter of wild, free-roaming horses and burros.

It was approved unanimously by voice vote.

"We need to stop the slaughter of wild horses and burros not only because it is morally wrong, but also because the program itself is a failure," said Rep. Nick Rahal, D-W.Va., a sponsor of the provision.

He said the prohibition is needed to counter action by Congress in 2004 that eased animal protections that had been part of the horse and burro adoption program since its inception in 1971. Those changes opened the way for animals to be made available for commercial slaughter.

Since then, 41 wild horses have been slaughtered "and thousands more face an uncertain fate," Rahal said.

The Bureau of Land Management, the agency that manages the adoption program, has told Congress that in light of the changes made in 2004, it had little control over what happens to the animals after they are sold.

Last year there were an estimated 32,000 wild horses and burros on public lands.