PORTLAND, Ore. (AP) – Advocates for wild horses have sought an injunction to stop researchers from surgically sterilizing more than 200 wild mares at a facility in Hines, Oregon.

The U.S. Bureau of Land Management has said the research would help determine whether the three methods to be studied could be safely used to control the wild horse population.

But the group Front Range Equine Rescue describes the experiments as unnecessary and barbaric.

Group president Hilary Wood says performing unproven surgeries is contrary to the BLM’s congressional mandate to care for wild horses, especially when an existing vaccine works as effective birth control.

The lawsuit seeking the injunction was filed Monday in Washington D.C.

The BLM did not have an immediate response the lawsuit Tuesday.