Surgical Castration of Horses, Donkeys, and Mules

August 13, 2019


The Canadian Veterinary Medical Association (CVMA) considers castration of horses, donkeys, and mules a major veterinary surgery, which should only be performed by a veterinarian using appropriate surgical, anesthetic, and analgesic techniques.


  • Surgical castration is an elective procedure which can pose significant welfare risk to the animal.
  • Castration is a painful procedure which requires close peri-operative monitoring and can be associated with serious post-surgical complications including blood loss, evisceration, infection and death.
  • Donkeys, mules, and mature horses carry the greatest risk of complication from surgery.
  • The CVMA strongly recommends provincial regulatory authorities regard the castration of horses, donkeys, and mules as an act of veterinary practice and regulate accordingly.
  • Castration without anesthesia and analgesia results in significant preventable animal suffering; therefore, the CVMA considers it to be animal cruelty.


  1. In some horses, donkeys, and mules (equids) the testicles may not descend into the scrotum until several weeks after birth and one or both may be retained within the inguinal rings and may not descend into the scrotum for several months, precluding routine neonatal castration (1,2).
  2. Castration of equids is a major invasive surgical procedure with considerable risk of post-surgical complications. The risk is greatest in donkeys, mules, and mature horses. This surgery is often performed for the benefit of the owner and to facilitate management of the animal (1). Elective surgeries on animals for human benefit carry the highest moral obligation for professionalism and humane methods including pain mitigation (3,4).
  3. Veterinary examination to establish normal scrotal anatomy and locate testicles prior to surgery is essential and may require sedation and/or general anesthesia in fractious animals. The surgical procedure should be performed in a location that is suitable for the implementation of sterile surgical procedures and the patient should have appropriate pre-operative preparation (1,2). The use of physical methods or muscle paralytics as the only form of restraint, without appropriate sedation, anesthesia and analgesia, to perform equine castration is considered to be animal cruelty. Anesthesia (local or general) and peri-operative analgesics must be used for pain control (5,6).
  4. Because of the likelihood of post-operative complication, attentive post-operative monitoring is essential. This should include appropriate instruction and information to the owner on monitoring and aftercare
  5. Provincial jurisdictions have legislative authority for the protection of animals. Non-veterinarians performing equine castrations may be held accountable under animal protection laws if horses are put in distress by such individuals performing the procedure (7).


  1. Green P. Castration techniques in the horse. In Practice 2001;23:250-260. Available from: Last accessed September 12, 2018.
  2. Searle D, Dart AJ, Dart CM, Hodgson DR. Equine castration: review of anatomy, approaches, techniques and complications in normal, cryptorchid and monorchid horses. Aust Vet J 1999;77:428-434. Available from: Last accessed September 12, 2018.
  3. Mason BJ, Newton JR, Payne RJ, Pilsworth RC. Costs and complications of equine castration: a UK practice based study comparing standing nonsutured and recumbemt sutured techniques. Equine Vet J 2005;37:468-472. Available from: Last accessed September 12, 2018.
  4. Moll DH, Pelzer KD, Pleasant RS, Modranski PD. A survey of equine castration complications. J Equine Vet Sci 1995;15:522-526. Available from: Last accessed September 12, 2018.
  5. Muir WW. Pain therapy in horses. Equine Vet J 2005;37:98-100. Available from: Last accessed September 12, 2018.
  6. Love EJ, Taylor PM, Clark C, Whay HR, Murrell J. Analgesic effect of butorphanol in ponies following castration. Equine Vet J 2009;41:552-556. Available from: Last accessed September 12, 2018.
  7. Code of Practice for the Care and Handling of Equines. National Farmed Animal Health and Welfare Council 2013. Available from: Last accessed June 7, 2019.