Please write to OSU to oppose spaying experiments on feral mares and fillies in short-term holding

  • Check out this link for more details:

Below is the text of my email. Please consider writing,emailing or calling to oppose this unethical proposal. Contact information can be found in the link above.

“To the OSU Institutional Animal Care and Use Committee:

I urge you to reconsider involvement in the proposed sterilization experiments on captive mustang mares in Hines, Oregon. While I understand that population control is necessary, the surgical sterilization of mustang mares in holding and/or on the range is certainly not the answer.

There can be no doubt that the proposed research is inhumane. The BLM itself has acknowledged the risk to the individual mares, and of course any unborn foals. The risk will only increase for fillies selected to undergo surgical alteration.

I work in the veterinary field and am well aware of the follow-up and recovery period involved when spaying small animals like dogs and cats. These animals have at least a week long recovery period in order to minimize the risk of tearing their stitches and are given pain medication and antibiotics. The risk of complications, such as sepsis, in these formally feral mares is high.

Not only is the proposed research barbaric and cruel for the mares in holding, but it also opens a potential gateway for management to propose spaying mares on the range. Spaying is both dangerous (at the individual and population level) and unnecessary. PZP can be used successfully in both captive and feral populations. Once spayed, there is no undoing the potential genetic loss to a herd.

Finally, the spaying of mares in a population would likely disrupt the balance of bands and thus the herd at large. The mares’ behaviour would undoubtedly change, and it is unknown how this would impact the stallions and their relationships with now consistently anestrus mares.

It is for these reasons that I simply cannot condone the proposed surgical sterilization research on the mares and fillies in Hines, Oregon. I ask Oregon State University to please reconsider their support and involvement in this unethical study.

Thank you for your consideration”



2 thoughts on “Please write to OSU to oppose spaying experiments on feral mares and fillies in short-term holding

  1. I agree with you on the pzp and the horses they are removing. Can you please tell me or give me an idea of which mares have been given pzp or plan to be?


    1. Sure, the PZP plan got really complicated last year so I’ll do my best to try and explain! Based on last year’s Environmental Assessment, all mares except those between the ages of 5-9 years are given PZP. So, if the PZP has a 100% success rate, mares ages 6-10 are the only ones foaling. Fillies are not given a primer until they are 18-21 months old. Once the mare is over the age of 21, she will not be boostered.

      The really tricky part is that they introduced various Thresholds to the PZP plan, so any mares within the PZP-free “window” meeting any of the following criteria will be put back on PZP until they are 21:

      1. 2 or more offspring surviving to over 1 year of age UNLESS both offspring have been removed by the BLM. So in this case, if Demure was still in the PZP free window she would have met this threshold as Mandan is on the range and Kindra died when she was over a year of age.

      2. Mares that were not darted when they were younger (I think this means they are darting horses like Kitalpha as they did not vaccinate her when she was a yearling as she was presumed dead)

      3. The older mares in the PZP free window can be vaccinated if one of the younger mares hasn’t met a threshold if the population exceeds the AML.
      (So they could have darted Galena as a 9 year old last year as the herd is over the AML at the moment)


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