Updated

Companies in New Mexico and Missouri could begin slaughtering horses within a few weeks after a federal appeals court removed a temporary ban that was preventing domestic horse slaughter from resuming for the first time since 2007.

The 10th U.S. Circuit Court of Appeals in Denver lifted an emergency injunction Friday that it had issued in November after animal protection groups appealed the ruling of a federal judge in Albuquerque. The judge said the U.S. Department of Agriculture followed proper procedure in issuing permits to Valley Meat Co. in Roswell, N.M., Rains Natural Meats of Gallatin, Mo., and Responsible Transportation in Sigourney, Iowa.

The appeals court's order Friday said the groups "failed to meet their burden for an injunction pending appeal."

Blair Dunn, an attorney for Valley Meat and Rains Natural Meats, said the order lifts the emergency status of the case, meaning it will likely be months before a final decision is issued.

Dunn said the plants are ready to open, although they could agree to remain shuttered if the plaintiffs agree to post a sufficient bond to cover the companies' losses should they ultimately prevail.

"They are getting ready to go as quickly as they can. It shouldn't take too long. Not more than two weeks," he said.

The Humane Society of the United States said, however, that "the fight for America's horses is not over."

"We will press for a quick resolution of the merits of our claims in the 10th Circuit," said Jonathan R. Lovvorn, the group's senior vice president of animal protection litigation and investigations.

The plants would become the first horse slaughterhouses to operate in the U.S. since Congress effectively banned horse slaughter by eliminating funding for inspections at the plants. Congress restored that funding in 2011, but the USDA did not approve the first permits for horse slaughterhouses until this summer.

The issue has divided horse rescue and animal welfare groups, ranchers, politicians and Indian tribes about what is the most humane way to deal with the country's horse overpopulation, and what rescue groups have said are a rising number of neglected and starving horses as the West deals with persistent drought.

The companies want to ship horse meat to countries where it is consumed by humans or used as animal feed.

Valley Meat and Responsible Transportation were set to begin horse slaughter operations in August, but U.S. District Judge Christina Armijo blocked their plans while she heard the lawsuit by The Humane Society of the United States, Front Range Equine Rescue and others. The groups claimed the plants should have been forced to undergo environmental reviews under provisions of the National Environmental Policy Act.

Responsible Transportation abandoned its horse slaughter plans and converted its plant to cattle before Armijo dismissed the lawsuit in November.

Attorneys for the plants have argued that the plaintiffs are simply in court because they are morally opposed to horse slaughter and are looking for a way to delay the plants while they lobby Congress for a ban.

Proponents of a return to domestic horse slaughter point to a 2011 report from the federal Government Accountability Office that shows horse abuse and abandonment have increased since domestic horse slaughter was banned. They say it is better to slaughter the animals in humane, federally regulated facilities than have them abandoned to starve across the drought-stricken West or shipped to inhumane facilities in Mexico.

Wayne Pacelle, president and CEO of The Humane Society of the United States, calls the practice barbaric and has said blocking a return to domestic horse slaughter "is an issue of national importance and scale."