RENO, Nev. (AP) — Wild horse advocates have dropped a lawsuit challenging roundups at a wildlife refuge on the Nevada-California line after federal officials severed ties with a contractor the critics claimed were allowing some mustangs that were gathered to be sold for slaughter.

Bonnie Kohleriter and Laura Leigh of the Nevada-based group Wild Horse Education said in a lawsuit filed in U.S. District Court in Reno the U.S. Fish and Wildlife Service couldn't account for the majority of the 140 horses J&S Associates of Mississippi rounded up last fall from the Sheldon National Wildlife Refuge.

They were scheduled to go before Judge Mirandu Du on Tuesday, but confirmed before a status hearing they were dropping the case after the service notified J&S on June 23 its contract had been terminated.