Equine and Camelid Castration

Castration complications

With any surgery, there are standard complications:


Equine castrations are generally performed in a non-sterile environment with incisions left open; contamination is ensured. As long as the incisions stay open for drainage, infection doesn’t typically cause any problems. Issues with infection develop when drainage is impaired (as when the incisions close up too soon) or when chromic gut is used to ligate the vessels (since it is highly irritating). Gut is rarely used for castration now and other suture types seem much safer.

Infection at the castration site can potentially extend into the abdomen, causing peritonitis. Subclinical peritonitis definitely occurs after castration but rarely causes issues. Open castrations are potentially riskier in that they open the peritoneal cavity but closed castrations carry other risks.


The testicular arteries can bleed well. Generally hemorrhage is controlled by innate clotting mechanisms, ligation or by pressure.

It is close to impossible to apply effective pressure to the testicular arteries due to their location.

Many castrations are performed without ligation, using only crushing to stimulate natural clotting. If the crush is not effective, hemorrhage can be significant and potentially fatal. To ensure a good crush, the emasculators need to be assembled and used correctly so that the crush is proximal on the cord and the cut is distal. New emasculators can accidentally cut with the crushing part of the instrument. Many practitioners use the emasculators on rope a few times to dull the new metal in the crush section.

Ligatures can be used to control hemorrhage. Modified Miller’s knots are more effective than typical surgeon’s knots but both can be used successfully. Use material that will not cause long lasting irritation (eg not chromic gut).


Swelling is always an issue with surgery and is always exacerbated in ventral locations such as the scrotal area. Swelling will occur with your surgery and is typically the most severe at 2-3 days postoperatively. After that time it should decrease gradually; continued swelling can indicate infection.

Swelling can be decreased by pressure, cold hosing, NSAIDs and exercise. As applying pressure in the area is tricky, that is typically not used.

Cold hosing can be used if tolerated by the horse. The hose should not be directed up into the incisions since that would be aiming directly into the abdomen. Some horses will not tolerate cold hosing and it is not worth the risk to the owner or to the horse.

NSAIDs should be part of your protocol both for analgesia and control of swelling.

Exercise will help to minimize and reduce swelling by encouraging blood flow and lymphatic drainage.

Hydrocoele is another complication that can lead to swelling. The tunic closes and peritoneal fluid fills the tunic giving the appearance that the horse has regrown his testicles.

Poor healing

Poor healing is generally related to the factors listed above or to foreign material in the wound. If the incision continues to drain and does not close, it is likely that there is or was a foreign body in the wound. General anesthesia and wound exploration is indicated. Persistent infection can lead to spermatic cord infection. Spermatic cord infection can extend into the abdomen and require abdominal surgery to remove the infected cord.


Tetanus is uncommon but is life-threatening and horses are very sensitive to the bacterium. The vaccine works well and is highly protective. A booster is required for full protection. Since castration is an elective procedure, horses should receive their initial tetanus toxoid at least two weeks prior to castration and can receive their booster shot at the time of castration.  If a horse must be castrated in a shorter time frame, tetanus anti-toxin is recommended to provide immediate protection. Serum hepatitis is a risk with tetanus antitoxin.

Tetanus vaccines are widely available; however, cold storage is necessary to maintain efficacy. Clients may not be aware of the careful handling and storage needed.


Evisceration is a risk for any abdominal incisions or wounds. Intestines are slippery and can fit through small holes, particularly when the holes are ventral. Gravity works in most parts of the world and once the intestines start to slide out, the weight of the exposed intestines means more is likely to follow.

Postop complication flow chart – downloadable version



Use your search powers (see the resource page), your new knowledge base and the resources below to try and find answers to the questions below.

  • When is postoperative hemorrhage considered significant? What would the owner notice?
  • Why is it important to not have the cord stretched out when applying the emasculators?
  • What would you ligate a cord with? Hint: Gut is bad.
  • If hemorrhage is significant, would you manage the colt standing or recumbent? What do you do? What if you can’t do that?
  • What extra supplies should you bring with you for castrations, just in case of hemorrhage?
  • ***********************************************************
  • When is postoperative swelling excessive? What size fruit?
  • What is the association between postoperative swelling and drainage?
  • When and how do you open up the swelling to allow it to drain?
  • Should the horse be on antibiotics? How do you know?
  • How do you prevent issues with postoperative swelling?
  • What is the time frame for swelling after surgery?
  • ************************************************************
  • What structures could come out the scrotal incisions besides intestines? What would an owner be able to identify to tell you about?
  • Are certain breeds, ages or conditions more prone to evisceration (eventeration)? What would you do to prevent issues?
  • What is the time frame for risk of evisceration after castration?
  • The animal stands up and is eviscerating. Do you manage him standing or recumbent?  What do you do? What if you can’t do that?
  • What extra supplies should you bring with you for castrations, just in case of evisceration?
  • **********************************************************
  • What is schirrous cord/ Why does it develop?
  • Are certain breeds, ages or conditions more prone to schirrous cord? What would you do to prevent it?
  • What is the time frame for when schirrous cord is likely to happen after castration?
  • How do you diagnose schirrous cord?
  • How do you treat schirrous cord? What if you can’t do that?
  • What extra supplies should you bring with you for castrations, just in case?
  • *********************************************************
  • When does penile trauma happen and what is needed for treatment?
  • When does hydrocoele happen and what is needed for treatment?
  • What does peritonitis look like and what is the treatment?


Try these cases to see if you agree with my recommendations:



A review of prevention and management of castration complications. Equine Vet Educ. 2024;36:97–106.

A prospective multicentre survey of complications associated with equine castration to facilitate clinical audit. EVJ 2019- spoiler alert – they didn’t find many complications. And the Brits are way ahead of us with proper analgesia.

How to treat castration complications in the field – video CE, 2019 article

How I manage castration complications in the field, AAEP 2015 p 224.

Incidence, management and outcome castration complications, JAVMA 2013

Open standing castration in Hong Kong: prevalence and severity of complications, EVJ 2018



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Large Animal Surgery - Supplemental Notes Copyright © by Erin Malone, DVM, PhD is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.