A citizen advisory panel has recommended sterilizing some of the wild horses and burros that live on federal land in the West. The Bureau of Land Management already uses vaccines to slow down horse reproduction and rounds them up for adoption, but there are thousands of those horses in captivity.

Now, members of the Wild Horse and Burro Advisory Board also want the Bureau of Land Management to consider sterilizing horses. They say the move would protect rangelands and control booming mustang populations in 10 Western states.

BLM has also been criticized for selling hundreds of horses over the last few years to a proponent of horse slaughter. Earlier this week, the agency acknowledged its inspector general is investigating allegations the Colorado man purchased more than 1,700 horses for slaughter in Mexico.