Ask the Vet: Castration

Question: What are the negatives to castration other than not being able to reproduce? Answered by Jennifer Reda, DVM, Steele Equine Veterinary Services, Zolfo Springs, FL and Stephanie Regan, DVM

Courtesy of AAEP.com 

Answer: Thank you for this great question. Many owners consider castration a routine procedure and expect that nothing could go wrong. In fact there are many complications that can occur, and the less severe of which are not infrequent. It is important to remember that whether it is performed in the field or in the hospital, whether standing and sedated or lying down under general anesthesia, castration is still surgery. As with any surgery, there is an inherent risk of complications, even when performed by experienced surgeons using proper techniques. It is estimated that about 10% of horses undergoing routine elective castration will experience complications related to the surgery, most of which are mild and can be resolved in the field with no long term effects.

Some complications that may occur after castration would be swelling or edema of the scrotum and surrounding tissues, bleeding, infection, or herniation of tissues or possibly even intestines through the castration sites. Some of these can be treated in the field—i.e. a swollen castration site can be manually reopened and then cold hosed and treated with anti-inflammatories, or bleeding from the spermatic cord may be able to be fixed by ligating the bleeding vessel in the field. Some complications may require referral of the patient to a hospital—such as if the bleeding cannot be stopped, or if the horse develops an infection of the spermatic cord develops that requires surgery to remove. A rare but serious complication is called eventration, where the intestine actually prolapses through the holes made to remove the testicles, and this would require immediate surgical referral. Certain breeds are more predisposed than others to this. Standardbreds and draft horses are good candidates for primary closure castrations at a referral setting for this reason. Any open castration, especially performed in the field, also has the chance of an ascending infection of the abdominal cavity, called peritonitis. This is also a serious, life threatening complication which may require hospitalization.

Other than surgical complications, there are no medical long-term negatives of being a gelding of which we are aware. Geldings live equally as long as stallions if not longer, they are fully athletic and capable of performing in every discipline, and they do not have some of the risks that stallions face for genital-related problems such as testicular cancers, scrotal hernias, and testicular torsions.

Don’t let these complications dissuade you from castration! Castration can be  a useful, vital procedure that creates healthy and happy geldings that will be serviceable to their owners for many years, if breeding is not a necessity. However, as your question so astutely points out, it is important to realize that there can be complications associated with castration, as there are with any surgical procedure. Below are some links to articles that may shed more light for you on the issue of castration complications and the statistics regarding their occurrence.


Question: I would like to know if the horse will really get bigger/muscular if he is castrated at an older age?

Answer: Thank you for the question. We see two aspects to your question here, the first being if the stallion gelded later would grow taller (bigger), and the second being if he would become more muscular.

To answer the first part of the question, we have seen research in multiple other species such as dogs, cats, cattle, and goats that castrating earlier actually enables them to grow taller. The theory behind this is that every animal has growth plates in each long bone in their body that close within a specific time window as the animal matures. When the growth plate closes, the animal’s growth in that long bone is completed. One factor influencing the timing of these closures is the presence of androgens, or sex hormones. In the other species, we have seen that early castration delays the closure of these growth plates, which causes the animals to grow taller than their intact counterparts.

The second part of your question is perhaps more difficult. We know that stallions that are allowed to remain stallions throughout their puberty age (12-18 months) do develop secondary sex characteristics such as a cresty neck. We see many muscular stallions in disciplines such as halter, Thoroughbred racing, and others. However, we have not found any research documenting that stallions are indeed more muscular than their gelding counterparts. In many disciplines, colts are left intact until management or performance is affected by undesired behaviors, but these horses are also generally wanted as breeding prospects if they are outstanding athletes. Further research is warranted on this topic.