Managing Post-Castration Complications in Horses

This article originally appeared in the Spring 2026 issue of EquiManagement. Sign up here for a FREE subscription to EquiManagement’s quarterly digital or print magazine and any special issues.

Equine castrations are common and perceived as straightforward elective procedures. However, 14.5% incur at least one complication. And according to Jesse Tyma, DVM, DACVS-LA, from Rhinebeck Equine in New York, the overall complication rate is anywhere between 10% and 60%.

“Veterinarians need to be aware of the potential complications in order to anticipate, recognize, and appropriately manage complications to optimize outcomes,” she explained.

Before beginning, ensure the horse is healthy with two testicles and no physical abnormalities, such as an inguinal hernia. She also advises clearly communicating the postoperative plan so clients know what to expect and when they should call with concerns. Potential complications and management strategies include the following:

Scrotal and Preputial Swelling

Some postoperative swelling is expected. “Get the horse moving,” said Tyma. “Administer NSAIDs, and use cold therapy. This typically resolves in days to a couple of weeks.”

Seroma

This can occur if scrotal skin at the incision is inadequately stretched or if postoperative swelling seals the wound prematurely. “Sterilely reopen and stretch the incision while the horse is sedated,” she said. “Again, exercise the horse, use NSAIDs and cold therapy. The seroma will take days to a couple of weeks to resolve.”  

Infection

Local infections can develop, typically presenting about two to six days postoperatively. Hallmarks of infection include swelling, purulent discharge, and possibly fever. “Treatment is the same as above, plus an antimicrobial, ideally guided by culture and susceptibility testing,” said Tyma. 

Scirrhous Cord (i.e., Septic Funiculitis)

Older horses and those castrated using the open technique are predisposed. Scirrhous cord can present weeks to months or even years later. 

“Clinical signs include swelling, failure to heal, a draining tract, and inguinal pain. The thickened cord can often be palpated inguinally and per rectum, and a transcutaneous and/or transrectal ultrasound can also aid in diagnosis,” Tyma explained. These horses should be referred to a surgical center to have the infected stump removed, as it can be a technically demanding procedure. With appropriate treatment the prognosis is good to excellent. 

Hemorrhage

This occurs uncommonly, in only 1.8-2.4% of cases. Older horses and poor surgical technique are predisposing factors. Bleeding stems most commonly from the testicular artery, but hemorrhage can occur at other sources.

“If the blood is dripping at one drop/second for more than 15 minutes, this is cause for concern,” said Tyma. “Try to identify and occlude the bleeding (Carmalt forceps are the hemostatic clamp of choice), ideally leaving them in place for 48 hours.” 

If this initial attempt is unsuccessful, pack the scrotum tightly with lap sponges or rolled or hemostatic gauze, and secure the scrotal skin. Leave packing in place for 48 hours. Keep the horse on strict stall rest and treat with antibiotics. 

If the horse has been bleeding for hours or at a steady stream, attempt hemostasis but also evaluate the horse systemically: Assess heart rate, mucous membranes, and jugular refill. Run a lactate, which provides more useful information about blood loss and shock than PCV/TS in cases of acute hemorrhage. If the horse is shocky without external bleeding, assess for hemoabdomen via abdominal ultrasound. Provide triage supportive care and refer immediately in cases in which hemostasis cannot be achieved and/or the horse is exhibiting signs of shock.  

“The prognosis is good as long as hemostasis can be achieved,” Tyma said. 

Septic Peritonitis

This is a rare but serious condition, usually secondary to an ascending infection. “These horses are sick. Conduct a thorough physical examination. Abdominal ultrasound, hematology, and abdominocentesis with cytology and culture are helpful in reaching this diagnosis. Refer these cases for intensive care,” emphasized Tyma. 

Eventration

Eventration is another very serious but rare complication, occurring in only 0.1-4.8% of cases. Standardbreds, draft horses, colts with large inguinal rings or hernias, and colts under 6 months of age are overrepresented. 

“This presentation requires rapid decision-making,” said Tyma. “The horse either needs surgical reduction and intensive hospitalized management or euthanasia.”

If referring, do your best to protect the prolapsed bowel, lavaging it to remove debris and reducing it into the scrotum, or sling it within a truss of a clean sheet or large towel secured over the hindquarters. Treatment includes surgical reduction of the bowel, ventral midline celiotomy, inguinal ring closure, peritoneal lavage, and possible resection and anastomosis, followed by intensive postoperative supportive care. Survival is fair at 44-77%. 

Omental Prolapse

Owners often mistake this complication for eventration. If it is just omentum, as assessed by close examination of the prolapsed tissue, then emasculate it and put the horse on antimicrobials. In age- and size-appropriate horses, palpation per rectum is recommended to ensure there is no bowel in the inguinal canal. If it happens again, then refer to close the ring. Outcomes for omental prolapse are good to excellent. 

Final Thoughts

To conclude, Tyma emphasized the importance of anticipation and early recognition of complications. She also said there is no shame in referral for castration in a more controlled environment, particularly for those predisposed to the more serious complications. 

Related Reading

• Disease Du Jour: Equine Castration Tips
• Tips on Performing Equine Castrations
• Equine Pain Assessment Tools and Techniques

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