Gelding

A gelding is a castrated animal—in English, the term specifically refers to a castrated male horse. The word comes from the Old Norse geldr ("barren")^[1].

A male horse is often gelded to make him more well-behaved and easier to control. Gelding also removes lower quality animals from the gene pool.^[2] Horse breeders choose to leave only their best animals as stallions; lesser specimens are gelded, to improve the overall quality of the breed.

To allow only the finest animals to breed on, while preserving adequate genetic diversity, it is recommended that only a small percentage of all male horses should remain stallions. Some sources place the percentage of stallions considered unacceptable breeding stock at about 90%.^[3], while others would be more radical and state that only 0.5% should be bred.^[4] In wild herds, the 10% ratio is largely maintained, though via a different mechanism, as a single stallion usually protects and breeds a herd of up to 10 or 12 mares.^[5]. (There are more males than this, but unattached male horses group together for protection in small "bachelor herds," an all-male group. See horse behavior and Horse breeding for more details).

Geldings are preferred over stallions for working purposes because they are calmer, easier to handle and more tractable^[6]. Geldings are therefore a favorite for many equestrians, especially amateurs. In many horse shows, due to the dangers inherent in handling stallions, requiring experienced handlers, youth exhibitors (and occasionally, women) are not permitted to show stallions in classes limited to just those riders^[7].

Geldings are often preferred over mares, because some mares become temperamental when in heat. Also, the use of mares may be limited during the later months of pregnancy and while caring for the young foal.

In horse racing, castrating a stallion may be considered worthwhile if the animal is easily distracted by other horses, difficult to handle, or otherwise not running to his full potential due to behavioral issues^[8]. While this means the horse loses any breeding value, a successful track career can often be a boost to the value of the stallion who sired the gelding, and the horse himself may win substantial purse money on the track, as he is apt to race for many more years than would a stallion, who is often retired to stud immediately following a short but successful track career.

Under British National Hunt racing (i.e. Steeplechase) rules, to minimize the health and safety risk for horses, riders and spectators, nearly all participating horses are geldings.^[9] On the other hand, in Europe, geldings are excluded from many of the most prestigious flat races including the Classics and the Prix de l'Arc de Triomphe^[10].

A horse may be gelded at any age; however, if an owner knows that he or she intends to geld a particular foal, it is now considered best to geld the horse prior to becoming a yearling^[11], and definitely before it reaches sexual maturity. While it was once recommended to wait until a young horse was well over a year old, even two, this was a holdover from the days when castration was perfomed without anesthesia and was thus far more stressful on the animal. Modern veterinary techniques can now accomplish castration with relatively little stress and minimal discomfort, so long as appropriate analgesics are employed^[12]. A few horse owners delay gelding a horse on the grounds that the testosterone gained from being allowed to reach sexual maturity will make it larger. However, recent studies have shown that this is not so: any apparent muscle mass gained solely from the presence of hormones will be lost over time after the horse is gelded, and in the meantime, the energy spent developing muscle mass may actually take away from the energy a young horse might otherwise put into skeletal growth; the net effect is that castration has no effect on rate of growth (although it may increase the amount of fat the horse carries)^[13].

Many older stallions who are no longer used as stud due to age or sterility can benefit from being gelded. Modern veterinary techniques make gelding even a somewhat elderly stallion a fairly low-risk procedure^[14], and the horse then has the benefit of being able to be turned out safely with other horses and allowed to live a less restricted and isolated life than was allowable for a stallion.

There are two major techniques commonly used in castrating a horse, one requiring only local anaesthesia and the other requiring general anaesthesia. Each technique has advantages and disadvantages.

Standing castration is a technique where a horse is sedated and local anaesthesia is administered, without throwing the horse to the ground or putting them completely "under." It has the benefit that general anaesthesia (GA) is not required. This method is advocated for simple procedures because the estimated mortality for GA in horses at a modern clinic is approximately 1 - 2/1000, and mortality in the field (i.e. where most horse castrations are performed) is probably higher due to poorer facilities.^[15]

For standing castration, the colt or stallion is sedated, typically with detomidine with or without butorphanol, and often physically restrained. Local anaesthetic is injected into the parenchyma of both testes. An incision is made through the scrotum and the testes are removed, then the spermatic cord is crushed, most commonly with either ligatures or emasculators, or both. The emasculators are applied for 2 - 3 minutes, then removed, and a careful check is made for signs of haemorrhage. Assuming that bleeding is at a minimum, the other side is castrated in the same manner. Most veterinarians will remove the testis that is held most "tightly" (or close to the body) by the cremaster muscle first, so as to minimise the risk of the horse withdrawing it to the point where it is inaccessible. The horse, now a gelding, is allowed to recover.

Standing castration can be performed in more complicated cases. Some authorities have described a technique for the removal of abdominal retained testes from cryptorchid animals^[16], but most surgeons still advocate a recumbant technique, as described below.^[17] The other drawback to standing castration is the risk that, even with sedation and restraint, the horse may object to the procedure and kick or otherwise injure the individual performing the operation.

Putting a horse under general anaesthesia for castration is preferred by some veterinarians because "surgical exposure is improved and it carries less (overall) risk for surgeon and patient"^[18] For simple castration of normal animals, the advantages to recumbant castration are that the horse is prone, better asepsis (sterile environment) can be maintained, and better haemostasis (control of bleeding). In addition, there is significantly less risk of the surgeon or assistants being kicked. In addition, in a more complex situtation such as castration of cryptorchid animals, the inguinal canal is more easily accessed. There are several different techniques (such as "open", "closed", and "semi-closed") that may be employed, but the basic surgery is similar. However, general anaesthesia is not without risks, including post-anaesthetic myopathy (muscle damage) and neuropathy (nerve damage),^[19] respiratory dysfunction (V/Q mismatch), and cardiac depression.^[20] These complications occur with sufficient frequency that castration has a relatively high overall mortality rate^[21]. To minimize these concerns, the British Equine Veterinary Association guidelines recommend two veterinary surgeons should be present when an equine general anaesthetic is being performed.^[22]

With either castration technique, the wound should be kept clean and allowed to drain freely to reduce the risk of hematoma formation, or development of an abscess. The use of Tetanus antitoxin and analgesics (painkillers) are necessary, and antibiotics are also commonly administered. The horse is commonly walked in hand for some days to reduce the development of edema (UK: oedema)^[23].

Complications following gelding are uncommon - according to one in-depth study, for standing castration the complication rate is 22%, while for recumbant castration it is 6% (although with a 1% mortality).^[24] The more common are:

• Post-operative swelling (edema) - minor and very common^[25]
• Scrotal/incision infection - either local or peritonitis have been reported. Chronic infection leads to a Schirrous cord - the formation of a granuloma at the incision site, that may not be obvious for months or even years^[26]
• Haemorrhage (bleeding)
• Evisceration (a condition where the abdominal contents "fall out" of the surgical incision - fortunately, this is uncommon,^[11], and has a survival rate of 85 - 100% if treated promptly.^[26]

The Scythians are thought to have been the first people to geld their horses^[27]. Geldings were once prized by classical steppe warriors for their silence; without mating urges, they were less prone to call out to other horses, easier to keep in groups, and less likely to fight with one another. These qualities are still valued today, particularly on modern cattle ranches where working horses are most easily kept in groups and also need to be ready to go at a moment's notice.

However, some cultures historcally did not and still seldom geld male horses, most notably the Arabs.^[28] These people usually used mares for everyday work and for war. Stallions used for ordinary riding are kept only with or near other male horses in a "bachelor" setting which tends to produce calmer, less stallion-like behavior in the animals, and culled males were usually sold away to those in other cultures, who lacked the cultural taboos against gelding them.^[29]

Famous racehorse geldings include the British Red Rum and Desert Orchid, the Irish Arkle, Australian Phar Lap, and American geldings Exterminator, Kelso, Forego, John Henry, Lava Man, and the 2003 Kentucky Derby winner, Funny Cide. Famous geldings in movies and television include Mr. Ed (Bamboo Harvester), and the two geldings who played the Lone Ranger's horse "Silver."

• Horse
• Stallion
• eunuch, ridgling, wether, and steer
• Spaying and neutering (for animals)
• Horse behavior
• Horse breeding
• Castration