Why the sterilization of Oregon’s wild horses is a bad idea


Priscilla Cohn says the planned surgical sterilization of wild horses in Oregon by the BLM is neither humane, nor economical.

The Bureau of Land Management, charged with the care of our wild horses, plans to sterilize 225 wild mares surgically at its corral in Hines, Oregon, in cooperation with Oregon State University. Its stated goal is to reduce the number of wild horses in order to decrease the cost of managing them.

Is this a good plan: will it solve the problem? The answer is no.


The planned sterilization experiments are preliminary, so that even if judged successful, they would require further studies; thus any results could not be expected for years. Therefore, it is neither effective nor economical.

Nor is the plan humane. Horses are social animals, forming powerful bonds with each other.

Owners know that horses frequently refuse to eat if separated from a companion. Racehorses are often given companions to keep them calm. Wild horses may be even more vulnerable than domestic horses when separated from members of their band. Scientists have observed that a stallion driven from his herd of mares by a younger stallion is often found dead shortly thereafter. It is said these stallions die from loneliness.

As if to corroborate this interpretation, observers have noted that if the younger stallion is not very aggressive, the older stallion may be permitted to stay on the periphery of the herd although not as an actual member of it. Their very nature thus reveals the extreme stress wild horses experience when they are driven out of their range, separated from their companions and used in experiments.

Even before invasive surgeries are performed, the helicopter roundups cause immense suffering and death. A horse’s natural defense is to flee from danger: old and young terrified horses often suffer serious injuries or death as they run from the low-flying, noisy helicopters, the very young struggling to remain with the herd. If they are separated, they are defenseless and become the next meal for a predator.

Recently newspapers carried an account of a foal, galloping beside his mother that managed to stay with the herd but wore his hooves down so far that he had to be destroyed. The costs of these roundups or their consequences are not accounted for in the BLM’s plan.

Similarly, the proposed surgeries carry with them a risk of death and danger of infection since they are not performed under sterile conditions. For example, it is not known whether ovariectomy (the removal of both ovaries) will cause the premature death of a fetus at certain gestational stages. (The horses subjected to this experiment will include pregnant mares and fillies barely over 8 months old). Furthermore, this procedure includes a greater risk of hemorrhage and evisceration and is more painful than other methods.

Compare these dangers to the use of PZP, a contraceptive that the BLM has refused to consider. Years of published research in refereed journals shows that PZP is highly effective, reversible, can be delivered remotely thus reducing stress, does not harm pregnant animals, has neither short nor long-term significant health effects, no significant behavioral changes, no passage through the food chain, and is low cost.

To choose a method that is invasive, inhumane, wasteful and which carries a high risk of death as opposed to an alternative that has no serious downside is unethical, to say the least.

Priscilla N Cohn is professor emerita from Pennsylvania State University. She is also associate director of the Oxford Centre for Animal Ethics, Oxford, England and has published seven books on topics such as ethics, fertility control, and ethics and wildlife.



This article has been written by a contributor to Horsetalk.co.nz.

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