The Truth, PLEASE

“Three things cannot be long hidden: the sun, the moon, and the truth.”
~ Buddha

You may remember that long before we were Chasing Horses Wild Horse Advocates, we have been sounding the alarm about the use of GonaCon on our mares and our fears that this experiment was permanently sterilizing our horses.  We were also concerned about what the experiment happening in Theodore Roosevelt National Park would mean to wild horses everywhere.

You may also remember that on March 30, 2022, Theodore Roosevelt National Park held a “Civic Engagement Meeting” to discuss what was then the NEW “Livestock Management Plan” that included the proposed management of the wild horses that call Theodore Roosevelt National Park home. 

You may ALSO remember – and if not you can view the entire transcript of the meeting here:

– that Jenny Powers, then introduced as NPS Wildlife Health Branch Chief with our National Biological Resources division, answered a question about GonaCon and the permanent sterilization of mares in Theodore Roosevelt National Park.

“Is there actual proof to the public that any of the horses have been in any way sterilized by the GonaCon?”

To which Jenny Powers answered: “Good question. We do have a couple of published papers showing that GonaCon is reversible, meaning that animals return to fertility post vaccination. However, with any individual animal it is possible that they could be permanently sterilized, and it is unknown at this time if our current herd has sterilized individuals or not. We’d have to play out the rest of their reproductive lives to know that.”

You may ALSO remember that Blake McCann was asked a similar question at the January 12, 2023 Livestock Management Plan public meeting – you can also read that transcript here:

“So Blake, as a result of mares treated with GonaCon, and you might wanna define what that is for folks on the phone who may not know what that is, how many have become sterilized or not returned to fertility.”

To which Blake responded: “Yeah. Thank you, Renee. GonaCon is an immuno contraceptive. Basically it utilizes the animal’s immune system to attack or withhold hormones that allow them to be reproductive. So that’s an explanation for GonaCon As far as the specific question of sterility, I’m not aware of any animals that have been sterilized by GonaCon. And from our evaluation and published research, we believe that it is a safe agent to use for purposes of population control. I have observed that animals are released from the effects of the contraceptive and they require boosters, so that’s at least some indicator there that we have not a completely lasting effect forever, but it is something that has to be maintained over time. Similar to other contraceptives that are used for horses elsewhere.”

You may ALSO remember that if you check Theodore Roosevelt National Park’s website – there IS a Frequently Asked Question that was answered with regards to when this Colorado State University “study” was completed: (

 When did the contraception research project end?

A36: Field research ended in 2020. The park continues to track contraceptive efficacy for management purposes.

Well, that is all quite interesting, isn’t it?

It seems as if we DO NOT have to worry about GonaCon permanently sterilizing our mares AND it would seem that CSU packed their bags in 2020 and stopped experimenting on our mares.


In an article published in September of 2021, the following fact was stated: (Please note that this article is looking for a solution to fertility control for monkeys)

“immunocontraceptive research in the United States has focused on a vaccine that instead blocks the effects of sex hormones. GonaCon stops females from cycling. After an initial injection and a single booster shot, 92 percent of mares in North Dakota’s horse-dense Theodore Roosevelt National Park remain infertile seven years later. The study is ongoing, and the hope is that infertility will prove to be permanent.”

NINETY-TWO PERCENT OF OUR MARES!!!! AND “The study is ongoing.”!!

How is it that in 2021 this known by people like Jenny Powers and Blake McCann, who have been part of this ongoing experiment on our mares BUT when questioned by the public, they seemed to have “forgotten” that the study results have shown that NINETY TWO PERCENT of our mares have been permanently sterilized?

That makes this fact from the park’s website even more concerning:

“To reduce foaling rates and minimize the number of animals that must be captured and sold annually to manage the herd size, Theodore Roosevelt National Park is administering GonaCon™ Equine immuno-contraceptive vaccine to all female horses ≥8 months of age.”

How can we trust anything that we are being told by Theodore Roosevelt National Park management?

It would seem that the park is already carrying out their plans to eliminate the ENTIRE herd of horses from the park.  With all of the mares permanently sterilized, this herd WILL eventually die out and be lost forever. 

This brings us back to the root of the problems with the mismanagement of the wild horses in Theodore Roosevelt National Park.  They are NOT protected in any way.  In addition  to a solid management plan, this herd needs to be protected under public law similar to the way that the wild horses at Cape Lookout National Seashore are. 

Chasing Horses Wild Horse Advocates is committed to advocating for a wild horse management plan and protection for these unique wild horses that call Theodore Roosevelt National Park home!  We are fighting for a management plan that is guided by science especially when it comes to decisions regarding the removal of horses and the administration of birth control.  Many other wild horse management plans have proven to be successful with their science-based plans.  We are asking for the same for this amazing group of wild horses that call Theodore Roosevelt National Park home.

4 thoughts on “The Truth, PLEASE

  1. This has always been my fear. We WILL save the horses but we have not stopped any of the contraceptive methods that have been used and as the blog states it would seem that the park IS carrying out their plan. It’s all smoke and mirrors for the people who run the park. They may lose this battle but we better watch out or they will win the war.

  2. I feel that this was completely done in an underhanded way. They knew what they were doing. What’s so horrible is that as mentioned the herd will eventually die off. Then they can open the land to what? Beef cattle and sheep. Again this is a livestock management problem. The ranchers have plenty of land if they would use it properly. A rotation basis would work fine. I just feel sick right now thinking about what’s happening out there.

  3. To know what they in fact did know and lied. How can we ever trust this group to take care and support our horses. Just asking

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