More than 30 wild horse advocacy groups are asking the Bureau of Land Management (BLM) to reduce the number of wild horse gathers and increase the use of the contraceptive vaccine porcine zona pellucida (PZP) to manage herd population growth.

The groups’ petition comes nearly one month after the BLM announced that the cost of caring for thousands of horses residing in long-term holding facilities is largely responsible for a more than $1 billion revenue shortfall.

On June 1, 34 wild horse advocacy groups—including the American While Horse Preservation Campaign (AWHPC), the Corolla Wild Horse Fund, Habitat for Horses, and the Salt River Wild Horse Management Group—called on the BLM to increase its use of PZP in wild herds. The groups maintain the expansion will reduce the need for horse gathers to maintain horses in holding facilities.

“America does not have a wild horse overpopulation problem, we have a mismanagement problem,” opined Suzanne Roy, executive director of the AWHPC. “The PZP fertility control vaccine (could help to) humanely manage wild horse populations in the west and beyond, and the BLM needs to step up the use of this available tool