I don't mean doing a full geld. More like a vasectomy. They still act like and think they are studs and can hold a herd because the hormones, and fend off bachelors. They just can't have babied. Coupled with fertility drugs it could help. They could also geld the less substantial colts and bachelor's too. That way better stock is left to breed.
We have the opportunity in the South Steens herd management area of Oregon, to observe what gelding/sterilization of stallions does for individual horses, the range, and the herd in general, measuring if there is benefit gained. This is one of several options of herd manipulation tactics for wild horse population growth suppression. In this particular herd area, 15 stallions were gelded at the time of the 2009 gather, translating to conservatively about 22% of male horses returned to the range- sterile- 15 out of about 65-70 males released post-gather operations, permanently altered. On the herd-level, while physically altering nearly a quarter of the stallions, it has made no apparent difference in population growth/suppression in 2012, however, on a micro-level in terms of the band social structures and order, range conditions, and effects on the individual animals, some adverse results have been realized.
We’ve found as costly and deadly as the procedure is even with skilled veterinarians (example, Calico Complex gather of 2010 - 30 gelded horses died as a direct result post procedure from infection and traumatic injuries), gelding the males has no overall benefit, simply because even one intact stallion can service receptive mares in season within the herd area- thereby the male sterilization option is an ineffective, expensive, and dangerous procedure or tool in herd management. To reiterate, here on South Steens, 15 males were gelded during the 2009 gather and released to the herd area- in other words, nearly a quarter of the returned male population was sterilized. While it had no bearing, a null effect on population growth, it has however, been observed to have an adverse effect on social order and natural behaviors of the horses. Gelded animals behave neither like mares or stallions, but rather a "well-mannered sub-species" if you will, and consequently, some apparent confusion among the animals. It has also been noted that there is a higher percentage of these gelded animals (which no longer "speak the same language" as their unaltered counterparts) in closer association with one another in their own micro-bands. In addition, permanent sterilization of wild horses does not follow the "policy of Congress that wild free-roaming horses and burros shall be protected from capture, branding, harassment, or death".
As for the individual sterile animal, there are body condition concerns which also come into question. It has been found that little motivation in movement cause altered animals to become overweight - and they are easily identifiable even from a distance simply by body shape and lethargy- much like a domestic without an exercise routine, however, this may cause considerable health risks. Gelded horses have no apparent regular/natural ambitions as the intact animals driven by hormones- hormones resulting in more mobility on the range, and like domestic animals will habituate to a specific area/location, the same is true for wild horses, causing over-grazing (further effect on localized wildlife habitat), leading to range damage. Quite opposite is true of intact stallions and mares which keep the bands mobile- movement throughout the HMA, attributed to natural hormones, causing less degradation on the range through what otherwise would be overgrazing a habitual or favored section.
Additionally, the practice of sex skewing, in favor of more males to females in a herd area (ie 60:40) does little to effect growth as well, however, adverse effects are also easily observed and on South Steens have been realized, following the injury and death of three known band stallions in less then a year as a likely result of more stallions to an area. Adverse and obvious in terms of increased and more intensive fighting of stallions, greatly resulting in high agitation, risk, and injury to the horses, including young foals which may be caught in the crossfire due to desperate and frustrated fighting stallions, either attempting to acquire mares, or defend their band from an unnatural increased amount of opportunistic bachelor stallions. A natural gender ratio of about 50:50 is ideal for a natural, balanced, and more harmonious mustang society.
While this is a brief and general outline highlighting merely a few simple effects easily identified by observers on the range, however, it is a complex issue in an equally complex ecosystem in terms of finding ways to preserve and protect the natural order of the range, mustang society, including other wildlife, in a multi-use model- Quite simply, a balancing act. It is a big job to effectively manage wild horse herds, maintaining them as natural and free of human interference as possible- as legally stipulated in the 1971 Wild Free Roaming Horses and Burros Act. However, we do also have to play the balancing game on the lands, as allotted areas for management are only so big. In my opinion, of all our options, “temporary” wild mare contraception is the key while permanent sterilization should not be part of the equation for appropriate wild horse management (side note: possibly a consideration for only aged mares, who have contributed to the gene pool- ie SpayVac injection).
The temporary (2 year) injectible PZP is simply administered every couple years to a percentage of mares on each HMA, through comparatively gentler methods of bait-trapping and/or remote darting- A process which is less costly to taxpayers and least invasive to the wild horses. This is an opportunity to responsibly manage wild horses and burros on the range with minimal impacts, costs, and trauma, potentially eliminating or minimizing the need for expensive roundups, while also reducing the cost of stockpiling/adding to the 50,000+ mustangs currently in government holding facilities (at taxpayer expense). PZP-22 has been tested successfully for over 20 years, with minimal side-effects, and offers about 2 years on average (+/- based on individual animal) of a reproductive block, helping to suppress overall population growth. In 2009 on South Steens, 59 mares were given the drug administered by injection, and as a result observed minimal births in years 2010 and 2011. In 2012 normal levels of birth rates resumed.
Wild mare contraception methods being ‘temporary’, we are able rotate use among the horses, assuring each can contribute to the genetic pool while at the same time keeping a population growth suppressed. Temporary wild mare contraception is a responsible opportunity to keep the population in check, while maintaining the bands in their natural structures, as well as less degradation to the lands. But moreover, we keep the integrity of our wild herds, with less intrusion to the natural horse, assuring genetically healthier and more viable bands- in turn thriving herds, and healthy ranges-
A balancing act- A benefit for all.
Sonya, aka Mustang Meg
follow on fb www.mustangmeg.com
PO Box 785
Lebanon, OR 97355