A wild horse herd along the Montana-Wyoming border that traces its ancestry to the mounts ridden by Spanish conquistadors could be reduced through adoption by more than 35 percent under recommendations released Monday by federal officials.

The U.S. Bureau of Land Management says a decade-long drought – coupled with overgrazing by the herd–is severely degrading portions of the Pryor Mountain Wild Horse Range near Lovell, Wyo.

To reverse that trend, BLM officials in a new study recommended reducing the herd through adoption to as few as 92 adult horses. The herd currently numbers 143 adults and several dozen foals.

“There’s definitely drought, but having too many horses during drought years magnifies the situation,” said BLM Wild Horse Specialist Jared Bybee