Authorities to deliver birth control drug to Utah wild horse herd by dart gun

Free-ranging wild horses. © BLM/Utah
Wild horses in Utah. © BLM/Utah

Federal authorities in Utah will use a long-term birth-control drug delivered by dart guns to control horse numbers in the Onaqui Mountain Herd Management Area.

The Bureau of Land Management (BLM) had notified the proposal through formal channels and subsequently signed off on the plan on May 1.

The department intends to use the drug, Porcine Zona Pellucida (PZP) on selected mares within the herd management area through to 2020, with the aim of keeping the adult herd numbers between 121 and 210.

The drug would be administered through darting by trained BLM personnel or collaborating partners only.

All mares targeted for treatment would be clearly identifiable through photographs to enable darters and managers to positively identify the animals during the project, and at the time of any subsequent gathers, the BLM said.

If it is determined that a mare or mares cannot be approached within darting range on foot, then baiting (not trapping) will be used to treat the mares.

Baiting will be with salt, mineral, or weed free hay in areas that horses use in their normal movements throughout the herd management area.

The BLM says the expectations for the fertility control program include the short-term goal of bringing herd growth rates to less than 7 percent. The long-term goal is to reduce the need for gathers and removals, without jeopardizing the genetic health of the herd.

The use of PZP has divided wild horse advocacy groups. Some see it as a sensible way to control wild horse populations, while others are concerned about health effects and the drug’s influence on herd dynamics.

PZP has been shown to prevent pregnancy in mares for one year or more, after which horses must receive the drug again.

There are 19 formally designated wild horse herds in Utah.

The Onaqui Herd Management Area is 40 miles southwest of Salt Lake City, on 43,880 acres of federal, state, and privately owned land.

Wild horses have occupied the Onaqul Mountains since the late 1800s. Most of the horses are descendants of horses that escaped from local ranches.

The dominant colors within the herd area are brown and bay. Other colors found include sorrel, roan, buckskin, black, palomino, and grey.

One thought on “Authorities to deliver birth control drug to Utah wild horse herd by dart gun

  • May 6, 2015 at 8:58 am

    210 horses on 83,880 acres of land = 208 acres per horse. Not exactly an overpopulation, especially when compared to the thousands of head of domestic livestock that usually also populate these herd management areas. If you follow the money you will find out the real reason the BLM wants to decimate wild horse herds. Welfare ranching, oil and mining, solar facilities, just to name a few of the corporations that are lining the pockets of the BLM, as well as profiting from the use of public lands (at taxpayer expense). Continued use of PZP leads to sterility. 210 horses is not enough to keep the herds genetically viable. The BLM continues to round up and warehouse horses treated with PZP. Contrary to what they tell you, the BLM has sold thousands of horses to known killbuyers. Tom Davis has magically made at least 1700 wild horses disappear after purchasing them from the BLM. There is a reason that “real” advocates for wild horses and burros can see through the BS from the BLM regarding the use of PZP to help the herds. Apparently there is more profit to be made from the corporations than the millions they get from the American taxpayer to “manage” wild horses.


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