Why not spay wild horses? Technique has barely been tested

(Beth Clifton collage)

Bureau of Land Management backs away from proposed trial of equine colpotomy

            PORTLAND,  Oregon––Asked a lifelong horse advocate and high donor to  wild horse,  cat,  and dog sterilization projects,  by email to ANIMALS 24-7,  “Do you have any ideas as to a competent equine vet with relevant experience who might be able to opine on the merits of equine spaying?”

Prompting the question was the apparent decision of the U.S. Bureau of Land Management to “cancel plans to spay wild horses in an effort to address overpopulation on Oregon public lands,”  as reported on November 8,  2018 by Everton Bailey Jr. of The Oregonian/OregonLive.

(Beth Clifton collage)

Blocked by injunction

“The development comes,”  wrote Bailey,  “after U.S. District Court Judge Michael W. Mosman on November 2,  2018 issued a preliminary injunction that blocked a Bureau of Land Management experiment to sterilize mares from the Warm Springs Management Area,  at a horse corral facility in Hines,  about two miles southwest of Burns,”  in the eastern Oregon high desert.

In newly filed court documents,  Bailey said,  “attorneys representing the Bureau of Land Management say the agency plans to not move forward with its spay study,”  but would continue to “remove ‘excess’ horses from the range” as deemed necessary to protect the habitat.

(BLM photo)

Colorado State University withdrew

The Colorado State University veterinary school,  after bidding to participate in the mare spaying experiment in August 2018,  had already withdrawn from it,  amid a storm of opposition from national wild horse advocacy groups,  when the Animal Welfare Institute,  American Wild Horse Campaign,  the Cloud Foundation,   and Carol Walker,  director of field documentation for the Wild Horse Freedom Federation,  on September 21,  2018 filed the lawsuit that stopped it.

The plaintiffs alleged that the proposed horse spaying experiments would “involve performing an outdated surgical procedure called ovariectomy via colpotomy,”  described by the plaintiffs as “a blind surgery in which a veterinarian inserts his arm into a mare’s abdominal cavity through an incision in the vaginal wall,  manually locates the ovaries,  then twists,  severs and removes them using a rod-like tool with a chain on the end.”

Omitted from the plaintiffs’ description of the procedure was that the procedure is performed using sedation and,  usually,  local anesthesia.

Leon Pielstick, DVM, prepares to perform colpotomy.  (BLM photo)

What the National Academy of Sciences really said

Continued the plaintiffs,  “The National Academy of Sciences explicitly called the procedure “inadvisable” due to health risks in its comprehensive report on wild horse management.”

But that is not actually what the National Academy of Sciences said in the 399-page 2013 report,  entitled Using Science to Improve the BLM Wild Horse & Burro Program: A Way Forward.

What the National Academy of Sciences did say,  on page 98,  is that “Colpotomy,”  unlike traditional flank spaying,  “avoids an external incision and reduces the chances of surgical complications or infection.  The mare is sedated and tranquilized while standing but restrained;  a local anesthetic is sometimes used as well to reduce movement during surgery.  An incision is made through the wall of the vagina and then through the peritoneum to access the ovaries.

Leon Pielstick, DVM, performing colpotomy.
(BLM photo)

Monitoring for 24-48 hours recommended

“Although the risks are lower than with transabdominal surgery,”  the National Academy of Sciences advised,  “episioplasty (suturing to close the vulva) and stall restriction for 2-7 days are recommended to reduce the chance of evisceration,”  if the sutures dissolve prematurely.

“Monitoring for 24-48 hours for signs of hypovolemic shock due to internal bleeding is also recommended. The procedure is not without risk,”  the National Academy of Sciences cautioned.

The National Academy of Sciences used the term “inadvisable” with reference to colpotomy only once,  in one specific context,  a comparison of potential approaches to contracepting or sterilizing wild horses on the open range,  as opposed to having to gather and corral the horses first.

(Beth Clifton photo)

Not meant for “field application”

While some chemical contraceptives can sometimes be administered to wild horses by darting,  no contraceptive or sterilization method tested so far has proved to be consistently effective without gathering and at least temporarily confining the horses as part of the procedure.

In that context,  said Using Science to Improve the BLM Wild Horse & Burro Program: A Way Forward on page 130,  “The possibility that ovariectomy may be followed by prolonged bleeding or peritoneal infection makes it inadvisable for field application.”

The now canceled Warm Springs Management Area colpotomy experiment did not involve “field application.”

(Beth Clifton photo)

Effects on herd behavior

What it was designed to test,  primarily,  was the effects of colpotomy on wild horse herd behavior.

Observed the National Academy of Sciences report,  “Although the cyclic production of estrogen by the ovaries is required for stimulation of estrus and mating behavior in virtually all species,  the horse is an exception.  The full repertoire of courtship and mating behavior has been displayed by ovariectomized mares and by anestrous mares during the nonbreeding season,”  meaning that colpotomy could potentially be used to control wild horse reproduction without inducing the behavioral abnormalities,  including excessive fighting among stallions,  that have inhibited the introduction of contraception using chemosterilants such as PZP.

(BLM photo)

Sheldon National Wildlife Refuge experiment

U.S. Fish & Wildlife Service biologist Gail H. Collins stimulated interest in colpotomy with a multi-year test of three different horse sterilization methods run from 2008 to 2014 at the Sheldon National Wildlife Refuge in Nevada,  the results from which were published in the Journal of Wildlife Management.

Summarized Wildlife Society science writer Dana Kobilinsky,  “Collins and her colleagues removed 10 to 20% of the [wild horse] population each year and sent them to contractors for private adoption,”  a term in itself suspect,  since “private adoption” programs,  even when governed by the Wild Free-Roaming Horses & Burros Act of 1971,  have often turned out to be schemes for selling horses to slaughter.

Gail H. Collins
(USFWS photo)

“Immediate success”

“They spayed 114 of the remaining mares and performed vasectomies on 268 stallions,”  Kobilinsky continued.  “Collins said the combination of permanently sterilizing females and males was successful in decreasing the foaling rate from over 20% a year to less than 4%.”

Assessed Collins herself,  “It was a pretty immediate success.  And we didn’t have to treat all of the males or all of the females,  only a little more than a third of the total population.”

Had the fate of the horses removed from the range been clearly documented,  Collins’ findings might have been better accepted by wild horse advocates.

(Beth Clifton collage)

But study resulted in evicting all the horses

But the U.S. Fish & Wildlife Service all but defined Collins––at least in wild horse advocates’ eyes––in describing on a web page why she won the 2015 Rachel Carson Award for Exemplary Scientific Accomplishment:  “Conclusions from Gail’s investigations provided the strong biological support needed to scientifically justify the controversial and complex decision to remove the feral horse and burro population from Sheldon National Wildlife Refuge..All feral horses have subsequently been removed from the refuge, ahead of the 2017 goal outlined in the refuge’s Comprehensive Conservation Plan.”

In other words,  the scientist said to have developed an effective and humane way to keep wild horses on the range without stressing the habitat, as part and parcel of the same study engineered the eviction of an entire herd of 1,800 wild horses from their habitat.

Wild horses dig for water.  (BLM photo)

2% mortality

Wild horse advocates,  having fought schemes to extirpate and exterminate wild horses on any and all public lands for more than 60 years,  are understandably mistrustful of anyone whose major career accomplishment is described by her employers as having sent 1,800 horses down the road in trucks to an unknown fate.

The 2018 edition of the Spay Feasibility and On-Range Behavioral Outcomes Assessment and Warm Springs Herd Management Area Population Management Plan,  updated from a 2016 version,  acknowledged that “There is always a risk of mortality associated with surgical procedures and the handling of wild animals. The anticipated risk of mortality associated with this procedure [colpotomy] is less than two percent,”  a high risk compared to the present risk of mortality associated with dog-and-cat spaying,  but comparable to the risk reported in studies done during the 1970s and 1980s,  when spaying dogs and cats rose to popularity.

(BLM photo)

Surgical procedure

“The proposed surgical procedure,  ovariectomy via colpotomy,  has the potential to cause discomfort for each mare following surgery,  as does any surgery,”  the Spay Feasibility report added.  “Details are incorporated into the procedure protocol to address pain management and to reduce the risks to the mare and the veterinarian performing the procedure (e.g. fully padded chute,  only one internal incision,  removing contraindicated mares from the study,  padded bumper above rump of the mare, chlorhexidine soak and sterile saline rinse of instruments).

“The results of the research,  the Spay Feasibility report said,  “would provide a better understanding of the beneficial and adverse effects of the ovariectomy via colpotomy procedure,  both on- and off-range,  and allow for more informed decision making in the future regarding wild horse population management methods.”

(Beth Clifton collage)

100 mares

The now cancelled test was to involve 100 mares,  among “approximately 852 horses currently residing in” Warm Springs Management Area,  who are believed to be a little more than 1% of the “81,000 wild horses and burros on-range across the western United States,”  according to the Spay Feasibility report.

The Bureau of Land Management has long sought a means of stabilizing and reducing wild horse herds more acceptable to the public than just removal for indefinite holding,  pending adoptions that absorb only a small part of the population captured,  or covert sale to slaughter.

Twenty-one years after the late immunocontraception pioneer Jay F. Kirkpatrick began testing experimental versions of PZP on wild horses in 1975,  the Bureau of Land Management in 1996 became the first U.S. wildlife agency to accept immunocontraception as an approved-and-available tool,  ready for use wherever it might be deemed appropriate.

Background: BLM wild horse roundup; the late Jay Kirkpatrick, who developed the horse contraceptive ZonaStat-H; foreground, Friends of Animals president Priscilla Feral.  (Merritt Clifton collage)

Resistance to contraception

Twenty-two years after that,  though,  the Bureau of Land Management is holding more than four times as many wild horses removed from public lands as then,  and is increasingly frustrated that almost every attempt to contracept horse herds is blocked or delayed by advocacy group lawsuits.

Among the most litigious foes of wild horse contraception,  though not part of the most recent Warm Springs Management Area case,  has been Friends of Animals,  consistent with nearly 30 years of FoA opposition to contraceptives for dogs and cats.

Promoting surgical sterilization of dogs and cats,  meanwhile,  was the original purpose of Friends of Animals,  incorporated in 1957.  Selling spay/neuter coupons still accounts for more than 40% of FoA revenue,  according to the 2018 FoA filing of IRS Form 990.

(Beth Clifton collage)

Proposed Wyoming test cancelled

Possibly hoping to end-run Friends of Animals opposition,  the Rock Springs,  Wyoming office of Bureau of Land Management in June 2011 announced that it would spay some of the mares from a roaming herd of about 1,000 wild horses,  hoping to reduce the population to about 400.

Just a week later the plan was cancelled.

“To do that we would need a research proposal,  since it hasn’t been done before.  And the research proposal wouldn’t be done in time,”  Bureau of Land Management spokesperson Cindy Wertz told Mead Gruver of Associated Press.

Boyd Spratling, DVM

Boyd Spratling, DVM

A year later,  in 2012,  Boyd Spratling,  DVM,  a past president of the Nevada Cattlemen’s Association and then chair of the BLM Wild Horse & Burro Advisory Board,  suggested that he might deploy a mobile clinic to spay wild mares at temporary holding facilities on the range.

“Surgery is never 100% safe,  but this is considered to be effective and relatively safe and has long been used in the racehorse industry,”  Spratling told Shannon Dininny of Associated Press.

But spaying horses,  either by colpotomy as Spratling recommended,  or by the older flank spay method,  actually has little history of use in the horse racing industry.

(Beth Clifton collage)

“In a round pen in the dirt”

Responded Ginger Kathrens,  founder of the Colorado wild horse advocacy group The Cloud Foundation,  also a member of the BLM Wild Horse & Burro Advisory Board,  “It’s not been done successfully.  It’s a surgery in a field in a round pen in the dirt.  How will it affect the health of the mare and the dynamic of the horse’s family and the larger herd?  They don’t know.”

And “they” will not find out,  as regards colpotomy,  nor will anyone else,  until the method is actually tested with wild horses somewhere.

In April 2013,  reported Nancy Lofholm of the Denver Post,  the Bureau of Land Management “laid out steps to study what are called ovariectomies,”  by seeking “input from veterinarians about the best way to conduct field spayings.

“If those veterinarians give the idea a green light,”  Lofholm wrote,  “the BLM would try out the procedure in holding facilities,  followed by research in the field,  before implementing any widespread program.”

(Beth Clifton collage)

Stalled

By March 2014 the Bureau of Land Management had invited research proposals for “creating new or improving existing techniques,  and establishing protocols,  for the contraception or the spaying or neutering of both male and female wild horses and burros.”

Nearly five years later the colpotomy proposal remains stalled more-or-less at that point,  with the wild horse population still soaring,  both on the range and in holding facilities.

So,  circling back around to the original question,  what do competent equine veterinarians think of equine spaying,  based on relevant experience in other contexts?

Few equine vets seem to have enough experience with spaying horses to venture an opinion.

Standing eqine laparoscopic ovariectomy
[flank spay].  (American College of Veterinary Surgeons photos)

“May be an effective treatment”

One exception is Peter Knox,  DVM,  of Nampa,  Idaho,  who advised in the June 2,  2015 edition of Practical Horseman that “Spaying,  also known as an ovariectomy,  may be an effective treatment” for “irritability, aggressiveness and pain linked to sex hormones released by the ovaries during heat cycles.”

Explained Knox,  “Ovariectomies reduce hormone levels by removing one or both ovaries.  Unlike dog and cat spays, the equine procedure does not remove the uterus.

“The safest ovariectomy procedure is done laparoscopically,  much like a human gall bladder surgery,”  Knox advised.  “It takes only about an hour with the horse standing in restraints under heavy sedation,”  or about four times as long,  as Knox would do it by the flank spay method,  as the colpotomy procedure recommended by the Bureau of Land Management.

Peter Knox, DVM

Does not recommend colpotomy

“Although there is some inherent risk in any surgery,”  Knox wrote,  “it is very low in this case because the surgeon can visualize the entire procedure and avoid or stop any bleeding.

“The most common postsurgical complications,”  Knox said,  “involve swelling and tenderness around the incision sites.  Mares usually experience minimal pain upon recovery from sedation and are administered an anti-inflammatory,  and a brief course of antibiotics to reduce risk of infection.  They can go home the following day, have the external sutures removed two weeks later,  and resume light work after about three weeks.

“I do not recommend an ovariectomy procedure called a colpotomy,”  Knox said.  “Even when performed by very experienced surgeons,  it has an increased risk of accidental injury to other organs,  bleeding and post-surgical colic.”

Rebecca Gimenez Husted.
(Facebook photo)

Second expert approves of flank spay

Rebecca Gimenez Husted,  who specified that she is “an animal physiologist PhD.,  not a vet,”  told ANIMALS 24-7 that earlier in her career,  as a vet technician,  she had “been privy to spaying two mares.  Both recovered nicely from the flank incisions.”

After “standing in the stocks for restraint under sedation and locals,”  Rebecca Gimenez Husted said,  the mares “walked out a few minutes after being stitched up,  no worse for wear.”

View from Australia

“Most techniques describe ovariectomy by a ventral midline approach with ovarian pedicle ligature prior to excision,”  offers the web site of the 15-veterinarian Goulburn Valley Equine Hospital,  operating since 1989 in Shepparton, Victoria state,  Australia.

“However,”  the Goulburn veterinarians advise,  “this is expensive and in our experience occasionally unnecessary.  Ovariectomy by colpotomy is an approach not often utilized,  despite being described centuries before the advent of powerful restraining pharmaceuticals.  We have used this technique in many mares without complication.

Safe as castration

“Clearly the technique has potential drawbacks,”  the Goulburn veterinarians acknowledge.  “However the procedure is safe and efficacious in many instances and able to be performed expediently by personnel experienced with examination of the female reproductive tract.

“Occasionally some mares strain during the procedure,”  says the Goulburn web site.  “Allowing more time for improved analgesia or additional analgesia appears effective.  Many of the complications such as evisceration and infection appear to be minimized by pre-surgical administration of IV phenylbutazone and prophylactic antibiotics.”

Overall,  the Goulburn Valley Equine Hospital staff believes,  “The [colpotomy] procedure is safe, expedient and efficacious,  and complication rate is similar to male castration.”

See Feline Fix by Five: the F-word campaign.  (Beth Clifton collage)

Changes in dog/cat spay procedure

Lack of current veterinary experience with equine colpotomy is not necessarily a strike against the procedure.

As recently as 1990 very few dog-and-cat veterinarians had any experience with small-incision spaying,  using a spay hook instead of their fingers to locate the animal’s uterus,  completing the procedure in the now standard 15 minutes to half an hour.

Spaying dogs and cats before their first heat was still controversial as recently as 1993.  Today dogs are commonly sterilized at six months or younger;  the optimal age for sterilizing cats is now five months or younger.

Beth & Merritt Clifton

That equine colpotomy has not yet been done much,  and has perhaps not yet been procedurally perfected,  does not mean that it should not be tested and improved,  especially if the most likely alternative is animals starving or dying of thirst on a depleted range,  or being sold to slaughter.

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