Fewer Bureau of Land Management (BLM) mustangs will be removed from the range and more mustang mares will receive anti-fertility treatment under a new management strategy plan announced by agency director Bob Abbey on Feb. 24.

Under the plan, the BLM will reduce the number of wild horses slated for removal during the next two years from 10,000 to 7,600, unless conditions such as drought or other emergencies require removing more animals.

The agency also intends to treat more mares with the contraceptive porcine zona pellucida (PZP). Injected as a liquid or fed in pellet form to fertile mares aged 4 to 20 years, a single PZP vaccination renders treated mares infertile for 22 months.

Abbey said the plan will be put in place in advance of results from a National Academy of Sciences/National Research Council (NAS/NRC) review of the BLM's wild horse and burro management operations