GELDING for the Greater Good - Vol 28 No 6

by Dr Barry Smyth
President,
Equine Veterinarians Australia

Management issues with colts and stallions are far greater than with geldings

Gelding, or castration of stock, is an important part of the breeding process, with many issues needing to be taken into account if a horse's usefullness, performance potential and health are to be maximised.

It could be said that the role that castration of a male horse - or gelding, as it is most commonly known - plays in the process of responsible and sustainable breeding is often not taken as seriously as it should be. Although castration is a relatively straight-forward and commonly performed type of surgery, there are many factors associated with the procedure that need to be taken into account if a horse’s health, welfare and future usefulness are to be maximised.

While male horses are usually gelded for management reasons - to prevent breeding or the development of stallion-like behaviour - there are other reasons for this type of surgery. Most of these relate to the correction of diseases specific to the male reproductive organs, including testicular torsion (twisting of the vessels and nerves), neoplastic (tumorous/cancerous) growths, inflammation (orchitis) and untreatable infertility. It may also be necessary in cases where there has been trauma inflicted on the inguinal area (between the hind legs) or as part of the surgery to repair an inguinal hernia.

Testicular Terms
Male horses have two testes where sperm are produced. The testes start as part of the embryonic (developing) tissues near the kidneys and migrate gradually down into the scrotum at or very soon after birth.

Sometimes, the migration of the testicles doesn’t happen in the normal way and either one or both remain within the abdomen - horses with this condition being known as cryptorchids. A horse may also have a testicle that is located somewhere between the abdomen and in the scrotum, in which case it is still regarded as a cryptorchid, but might also be referred to as a ‘high flanker’. In very rare individuals, only one testicle develops.

A cryptorchid poses a problem where castration is concerned as, in these cases, the gelding procedure becomes more complicated and therefore expensive - needing to be carried out under general anaesthetic and with the horse lying on its back, as opposed to the more usual side-lying or standing posture. The cryptorchid condition is thought to be hereditary. eg. colt foals sired by a cryptorchid stallion are more likely to be cryptorchids, however, definitive studies are lacking.

An interesting and unethical aside to the cryptorchid condition is that some owners have been known to request the insertion of a prosthetic testicle into the scrotum to give the external appearance that the horse is normal. Sadly, where this has been done, these horses often suffer prolonged problems because of infections or reactions against the implant.

Timing
Gelding can be carried out at any time after birth, provided that both testes have fully descended into the scrotum and can easily be felt, which has normally occurred by about three months of age. If there is any doubt about the presence of both testes in the scrotum, the vet due to perform the surgery should advise the owner of this so a decision to proceed, or to wait until a later time, can be made. Waiting will be of no use, however, if the horse is older than three months or so and its testicles aren’t descended properly, as they then are highly unlikely to do so.

The younger a horse is castrated, the fewer post-operative complications encountered. Mature stallions seem to take much longer to recover from the surgery and the local blood supply to the area surrounding the testicles is much greater than in a younger horse, which increases the chances of excessive post-operative bleeding. Between one to two years is usually the most appropriate time, as this is when a colt will begin to show masculine behaviour such as increased aggression and mounting other horses. The majority of a horse’s growth has been completed by then but, of course, it will still be another two or three years before a fully mature size is reached.

There is no evidence to suggest that the gelding of colts at an early age ‘stunts’ their growth - just that they won’t develop the same level and type of masculine traits that can usually be seen in those castrated after puberty (that is, after three or four years of age). For example, horses gelded later have a more ‘masculine’ head and jowl with increased muscling of the neck and rump.

To Geld or Not To Geld
The issue of which male horses should be kept entire and which should be gelded is a contentious one, as this decision is not always made in an objective manner nor in the best interests of the breeding industry as a whole. Also, what is a ‘desirable’ trait in some breeds would not be acceptable in another and, especially when it comes to temperament, there is a large variation in what individual owners are willing to tolerate in their horses.

Often, the decision to castrate a horse is delayed far too long, as many owners like to ‘see how he will turn out’ before deciding on whether to keep a colt entire. If the length of time for the decision-making process turns into a matter of years, however, the horse will then have matured into an adult stallion, with all the accompanying management issues to deal with.

Something that always should be kept in mind, however, is that uncastrated horses should be used for breeding only if they are ‘superior’ individuals capable of passing on desirable attributes. In particular, there is little room for sentiment if a colt displays conformation or other faults that are known to be genetically based, as these undesirable characteristics can then be passed on to future generations. On the other hand, however, horses carrying an undesirable trait often also have other characteristics that are highly desirable and sought-after in the breed.

An interesting sideline to this debate is the fact that progeny testing, as undertaken in other animals to select breeding stock for particular traits, has not been done commercially in horses. This appears to be due largely to the reluctance of the equestrian industry to define specifically what is acceptable ‘across the board’ or to determine the genetic basis of desirable traits. Curiously, it seems that stallion owners (and mare owners) are more than willing to embrace the technologies that increase the number of offspring (like semen processing and embryo transfer techniques, for example), but are reluctant to pursue those investigations where the information gathered might impact negatively on the ‘bloodlines’ of their horses.

There is some evidence that this selective attitude to ‘better’ breeding is changing on a global basis, especially in Britain, where an industry-wide plan has been adopted to, in part, ‘increase the quality’ of British horses. Breed societies also have an important role to play in the identification of undesirable faults and in the decision-making process as to whether such affected animals should be part of the breeding herd.

Obviously, this is a very complex issue and there are no easy answers, which is why the topic of whether to ban breeding of animals with known genetic defects is currently a subject of much angst and discussion among the animal welfare community around the world. Read what has been happening in England at the following links:

Companion Animal Welfare Council (May 2006) Report on Breeding and welfare in companion animals at http://www.cawc.org.uk/documents/CAWCModifications.pdf

Farm Animal Welfare Council (June 2004) Report on the welfare implications of animal breeding and breeding technologies in commercial agriculture at http://www.fawc.org.uk/pdf/breedingreport.pdf

Twisty cats - the ethics of breeding for deformity by Sarah Hartwell at http://www.messybeast.com/twisty.htm

Castration In Close-up
Castration, in relation to a male horse, is a type of surgery whereby the testes (or testicles) are removed - a process also commonly referred to as orchidectomy, emasculation, gelding or cutting. It can be carried out while a colt or stallion is standing, but is more often done under general anaesthesia in a lying position - especially if the patient is less than 12 hands high (too hard for the vet to easily gain access to the testes). Due to their reputation of kicking out, even when heavily sedated, donkeys and horse cross-breeds like mules are also not suitable candidates for a standing procedure.

If gelding is to be carried out at a horse owner’s property, a suitable place needs to be chosen and prepared prior to the veterinarian’s arrival. Ideally, an outside area should be as clean as possible, preferably well grassed, free from dust, away from fences, cleared of obstacles such as rocks and out of the wind. If the surgery is to be done in a stable, either a bare dirt floor or straw bedding is acceptable, but shavings and paper are not recommended, as these materials contain too much dust and other airborne particles that could be a source of contamination.

For castration while lying down (recumbent), the horse can be on either side then the upper rear limb is lifted away from the scrotum (pouch of skin that contains the testes) - usually by passing one end of a rope around the leg near the hoof then tying the other end securely to the neck.

If gelding is to be carried out while standing up, the horse must have a co-operative temperament and have been taught to remain still and relaxed while its abdomen and scrotal area are handled (palpated). Most importantly, the person holding the horse for a standing procedure needs to be very experienced and familiar with what is to be done and when, and to be aware of the horse’s likely reaction at every stage. This is not a task for the faint-hearted, it seems, with many a veterinarian having witnessed the disconcerting and potentially dangerous sight of the handler being overcome with nausea and even collapsing part way through the surgery!

Open vs Closed
After anaesthesia has been given, the scrotal area is thoroughly cleaned and scrubbed to remove dirt, sweat and any discharges. The first testicle to be removed is then held firmly against the skin and a cut is made so the testicle and all the other structures associated with it can be brought to the outside of the body. An emasculator (instrument designed to crush the tissues, thereby preventing excessive bleeding), is then used to clamp the blood supply to the area while the testicle is cut out and checked to ensure all relevant tissue has been removed. After a period of time, which varies according to the vet’s preference, the emasculator is taken off and the whole procedure repeated on the other testicle.

The method described above is known as the ‘open’ method because all testicular tissue is exposed before it is removed. ‘Half-closed’ and ‘closed’ surgery can also be carried out but, with these methods, more care and expertise is required to ensure the right tissues are removed and that there is no intestine trapped with the testicle. Laparoscopic (key-hole surgery) castration is another technique but this requires very expensive equipment and specialised training, so is usually only done in cases where a testicle is known to be within a horse’s abdomen.

Post-Operative Care
Full recovery from the sedation and anaesthesia takes a couple of hours so, during this time, the horse must be kept as quiet as possible to ensure it is fully awake before being left alone and to allow bleeding to stop. Light exercise can be resumed after this but the amount and type will vary depending on the environment the horse is kept in, with a large paddock often providing enough opportunity for self-exercise but those predominantly confined to a stable or yard may need to have a more structured program.

Most importantly, the horse should be carefully monitored for several days post-surgery and anything unusual in the recovery process, such as a persistent discharge, disinterest in feed, depressed outlook or change in exercise tolerance, reported to the vet who performed the surgery so treatment can be administered promptly if necessary.

Minor Complications
Complications such as swelling, superficial infections, pain, lameness, fluid accumulation, failure to remove all or part of a testicle, damage to surrounding tissues during standing castration and peritonitis (abdominal infection) can all occur in association with castration.

Although it is not unusual for some blood to be coming from the incisions for up to an hour post surgery, excessive, uncontrolled bleeding is not normal. In cases where large volumes of blood are being lost, a vet may clamp or ligate (tie off) the source of the haemorrhage or insert a sterile pack under pressure, leaving this in place for several days.

Swelling between the rear legs is very common after a horse has been gelded and is mostly only a few centimetres but can reach 30 to 40 cm in diameter if the skin wound closes over too quickly, preventing adequate drainage. Strict attention to post-operative exercise, hosing and cleaning the area are the most common treatments but anti-inflammatory and antibacterial or antibiotic drugs may also be prescribed to help control the problem.

In some horses, a piece of omentum (a thin, filmy, fat-filled tissue within the abdomen) can protrude through the open skin incision. Omentum acts as the ‘policeman’ of the abdominal cavity in that, if there is any problem in this area, it will migrate there either to fill a hole (such as left by castration), or to isolate an abnormality (such as an infection or damage to intestine). Protrusion of a piece of omentum can be a worrying sight because it can appear like the far more serious complication of evisceration (protrusion of the intestine) but, in fact, it can be easily treated.

Persistent ‘stallion-like’ behaviour is still seen in up to 30% of male horses after castration but this often settles down in time. If not, then there might be some remaining testicular tissue - a possibility that can be checked for with laboratory assays.Owners must remember that castrated horses will remain fertile for several days after the surgery and so should be separated from female horses for at least two to three weeks.

Serious Complications
Potentially the most serious post-operative complication is evisceration - that is, protrusion of a portion of the intestine from the wound site. This happens most commonly in the first 24 hours or so, but might not be encountered for up to a week afterwards.

If evisceration happens, the horse must be kept as quiet as possible and emergency veterinary attention called for, as this is a life threatening situation. A general anaesthetic is required to enable the protruding intestine to be thoroughly cleaned and replaced as quickly as possible. If this is not able to be done on the owner’s property, the site can be secured with drapes or skin sutures before the horse is transported to a surgery.

In many cases of evisceration, some of the intestine will need to be removed because it has become damaged during exposure to the environment. With prompt attention, however, most horses can be saved and go on to have productive careers.

The possibility of evisceration can be prevented by using a closed castration method (under general anaesthesia) and applying a suture (stitch) across the site of tissue removal. This closes off the communication with the abdominal cavity and prevents any intestine from reaching the external environment.

If there is a long-term, ‘pus-like’ discharge from the site of a castration, this may be due to a type of deep tissue infection that doesn’t respond satisfactorily to antibiotic or antibacterial treatment. Usually, the best option for this situation is for a vet to do a complete removal of the infected tissue under general anaesthesia.

Supplied by Equine Veterinarians Australia (EVA).
For information on EVA go to the web site: www.eva.org.au

ABOUT THE AUTHOR
Dr Barry Smyth is currently a Registered Specialist in Equine Surgery
in Victoria and President of Equine Veterinarians Australia, and has many years of experience in academia, research and clinical equine practice in Australia and overseas.