Wild horses at Bureau of Land Management corrals in Hines, Ore. BLM photo.
The Bureau of Land Management has proposed doing spay research on mares captured during an October 2018 roundup at the Warm Springs Herd Management Area in Oregon. BLM aims to determine the feasibility of performing ovariectomies via colpotomy.
This is a rare procedure which removes the ovaries by crushing and pulling them out with a looped-chain medical instrument called an ecraseur. This procedure opens the mares up to: serious risk from infection; evisceration (should intestines come through the incision); and hemorrhaging. There is a high frequency of post-operative complications affiliated with ovariectomy via colpotomy, some of which can be life-threatening.
BLM has gone down this road before: It's twice proposed sterilization studies on mares from Warm Springs only to drop the plan after a public outcry and lawsuits filed, or threatened, by advocacy organizations.