RENO, Nev. (CN) - Animal rights groups asked a federal judge to stop the "forced drugging of mares" and the planned removal of 332 wild horses from the Pine Nut Herd Management Area near Carson City.
Friends of Animals and Protect Mustangs sued the BLM Monday in Federal Court.
They claim that the BLM plans to round up the horses in late January or early February and administer a "fertility control drug, porcine zona pellucid (PZP), to all mares one year of age and older," then return them to the 90,000-acre herd management area.
Most of the horses will be removed permanently, but "the PZP-dosed mares" will be returned to the management area.
The groups say the BLM did not provide reasonable public notice of the removals or allow time for public comments, as required by the Administrative Procedure Act.
Nor did the BLM "evaluate the physical, behavioral and social impacts associated with the use of PZP on wild mares," as required by the National Environmental Policy Act, according to the complaint.
The BLM claims it fulfilled its obligations under the two acts when it published an environmental assessment for managing the Pine Nut herd and others in 2010.
But Friends of Animals says the bureau cannot fulfill its obligations to place "public and interested organizations on notice" of the "hasty roundup in 2015" by issuing a document more than four years ago.
The 2012 environmental assessment did not address the use of PZP, Friends of Animals says, and the drug "likely creates instability in wild horse bands, affects the health of the group members, and can increase wild horse mortality."
The groups want the BLM enjoined from carrying out the roundup and drugging, ordered to abide by federal laws, and attorney's fees and legal costs.
They are represented by Jennifer M. Spencer of the Cavanaugh-Bill law firm, in Elko.
Friends of Animals has a program for managing herds of wild horses and burros, which grows by about 20 percent each year, according to the BLM.
The BLM says it relocates wild horses primarily to large ranches in Kansas and Wyoming, where they have some 289,000 acres of grassland on which to roam and feed. Large herds can damage local ecosystems and face significant loss of habitat due to severe drought in many western states
The horses also are available for adoption .
Read the Top 8
Sign up for the Top 8, a roundup of the day's top stories delivered directly to your inbox Monday through Friday.