BILLINGS – A Montana rancher illegally used tissue and testicles from wild sheep killed by hunters in central Asia and the U.S. to breed “giant” hybrids for sale to private hunting preserves in Texas, according to court documents and federal prosecutors.

Arthur “Jack” Schubarth, 80, of Vaughn, Montana pleaded guilty to felony charges of wildlife trafficking and conspiracy to traffic wildlife during an appearance Tuesday before a federal judge in Missoula. Each count carries a maximum penalty of five years in prison and a $250,000 fine.

Beginning in 2013 Schubarth conspired with at least five other people in “a decade-long effort to create giant sheep hybrids” that would get higher prices from hunting preserves that allow people to kill captive trophy game animals for a fee, prosecutors said.

Schubarth used flesh obtained from a hunter who had killed a sheep in Krgyszstan belonging to the world’s largest species of the animals — Marco Polo argali sheep — and used the genetics to procure cloned embryos from a lab, according to court documents.

The embryos were later implanted in a ewe, resulting in a pure Marco Polo argali sheep that Schubert named “Montana Mountain King,” the documents show. Semen from Montana Mountain King was then used to artificially impregnate other ewes to create a larger and more valuable species of sheep, including one offspring that he reached an agreement to sell for $10,000, according to the documents.

Male argali sheep can top 300 pounds with horns up to 5 feet long, making them prized among some hunters.

In 2019, Schubarth paid $400 to a hunting guide for testicles from a trophy-sized Rocky Mountain bighorn sheep that had been killed in Montana. Schubarth extracted the semen from the testicles and used it to breed large bighorn sheep and sheep crossbred with the argali species, the documents show.

Assistant U.S. Attorney General Todd Kim described Schubarth’s actions as “an audacious scheme to create massive hybrid sheep species to be sold and hunted as trophies.” Kim said the defendant violated the Lacey Act that restricts wildlife trafficking and prohibits the sale of falsely labeled wildlife.

Schubarth said when reached by telephone on Wednesday that his attorney had advised him not to talk about the case.

“I would love to talk about it but can’t do it now,” he said. His attorney, Jason Holden, did not immediately respond to telephone messages seeking comment.

Authorities agreed under the terms of a plea deal not to pursue further charges against the defendant pending his cooperation in the government’s ongoing investigation in the wildlife trafficking case.

Montana Mountain King is in the custody of the U.S. Fish and Wildlife Service, according to Department of Justice spokesperson Matthew Nies. As part of the plea deal, Schubert agreed to quarantine any other sheep containing Marco Polo argali genetics and any bighorn sheep that were harvested from the wild.

The deal also allows federal wildlife officials to inspect and, if needed, neuter the animals.

Captive animal facilities where game species can be raised and hunted were banned in Montana under a 2000 ballot initiative. But they remain legal in some other states.

Schubarth’s 215-acre ranch is state licensed as an alternative livestock facility, said Montana Fish, Wildlife and Parks spokesperson Greg Lemon. It was grandfathered in when the 2000 ballot initiative passed and has continued to operate, although hunting is prohibited, Lemon said.