Complications associated with closed castration using the Henderson equine castration instrument in 300 standing equids.

Objective: To describe a closed castration technique in standing equids, report associated complications, and identify potential risk factors.

Study Design: Prospective cohort study of 300 standing equids that were castrated with the Henderson Equine Castrating Instrument.

Methods: Thirteen participating veterinarians recorded intraoperative difficulties and postoperative complications. Descriptive statistics, univariate analyses with Fisher's exact tests, and logistic regressions were used to evaluate intraoperative difficulties and postoperative complications and to assess risk factors for postoperative complications.

Results: Data were collected on 300 equids (269 horses, 23 ponies, and 8 donkeys). Intraoperative difficulties were experienced in 39 of 300 (13%) procedures. Postoperative complications were reported in 69 of 300 (23%) equids, including excessive swelling (29, 9.67%), surgical site infection (SSI; 27, 9%), severe hemorrhage (3, 1%), and prolapse of the omentum (2, 0.64%). Donkeys were at increased risk of severe hemorrhage (2/8, 25%, P = .0019). Equids that were castrated in a hospital setting (83/300, 27.66%) more frequently developed excessive swelling (P = .0034, odds ratio [OR] = 3.20) and SSI (P = .0047, OR = 3.18) compared with equids that were castrated in a field setting (217/300, 72.33%). Prolonging antimicrobial prophylaxis or age of the equid at the time of castration had no effect on the prevalence of excessive swelling or SSI.

Conclusion: The method of castration evaluated here resulted in a similar prevalence of postoperative complications to that previously reported for castrations in standing horses but fewer SSI.

Clinical Significance: The described method provides a viable option for castrating horses and ponies, but is not recommended in donkeys.