Position Statements

Surgical Castration of Horses, Donkeys, and Mules

December 11, 2024

Position statements developed by the CVMA reflect current knowledge regarding animal welfare. While they are not legislative, they do represent CVMA’s ongoing commitment to the advancement of animal welfare.

Position

Castration is a surgical procedure which can pose a significant welfare risk to the animal. This should only be performed by a veterinarian using appropriate surgical, anesthetic, and analgesic techniques. It is routinely performed in animals up to two years of age, which is substantially older than other farmed animal species (1) and therefore poses higher risks of both intraoperative and postoperative complications.

Summary

  • Castration is an elective surgical procedure which can pose significant welfarerisk to the animal. It is routinely performed on animals up to two years of age,which is substantially older than other farmed animal species (1).
  • Donkeys, mules, and mature horses carry the greatest risk of complicationsfrom surgery.
  • Castration is a painful procedure which requires close peri-operative monitoringand can be associated with serious post-surgical complications including bloodloss, evisceration, infection and death.
  • The CVMA strongly recommends provincial regulatory authorities regard thecastration of horses, donkeys, and mules as an act of veterinary practice andregulate accordingly.
  • Castration without anesthesia and analgesia results in significant preventableanimal suffering; therefore, the CVMA considers it to be animal cruelty.

Background

  1. Castration of equids is a invasive surgical procedure with considerable risk of post-surgical complications. (1-4). The risk is greatest in donkeys, mules, and mature horses compared to neonates and horses younger than two years of age. This surgery is usually performed for the benefit of the owner and to facilitate management of the animal. It avoids unwanted pregnancies and reduces aggression towards humans and other animals (5). Elective surgeries on animals for human benefit carry the highest moral obligation for professionalism and humane methods including pain mitigation (6,7).
  2. Horse owners should be strongly encouraged or required to provide basic halter and handling training for their horses before the castration procedure (8,9). This reduces both risk and stress for the animal and personnel.
  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.
  4. 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 (1,5,10).
  5. The surgical procedure should be performed in a location that is suitable for the implementation of sterile surgical procedures and safe induction and recovery from general anesthesia and the patient should have appropriate pre-operative preparation (5,10). Because of the risk of post-operative complications, attentive post-operative monitoring is essential. This should include appropriate instruction and information to the owner on monitoring and aftercare including pain control and recognition of post operative complications such as infection.
  6. The majority of horses develop significant hypoxemia under field anesthesia conditions, particularly in dorsal recumbency. If available, pulse oximetry should be employed and supplemental inspired oxygen provided. (11)
  7. Castration of horses with a primary closure technique under general anesthesia in a surgical facility will reduce the risk of complications. It should be considered in mature animals, particularly in horses known to be at higher risk and/or those of high value (3,4) There are also benefits of performing routine castrations at a hospital or fixed facility as more rapid intervention is possible in case of complications.
  8. 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 (12).
  9. General anesthesia alone is not adequate for providing surgical analgesia. Anesthesia (local or general) and peri-operative analgesics must be used for pain control (12-14).
  10. Provincial jurisdictions have legislative authority for the protection of animals. CVMA encourages all veterinary regulators to consider equine castration as a surgical procedure and as such supports the position in the Position Statement on Surgical Procedures Performed in Animals that it should be performed by a licensed veterinarian (15). If a non-veterinarian performs an equine castration, they should be held accountable under animal protection laws if horses are put in distress by such individuals performing the procedure (8).

References

  1. Baldwin CM. A review of prevention and management of castration complications. Equine Vet Education.First published: 23 August 2023 https://doi.org/10.1111/eve.13880 Last accessed September 19, 2024.
  2. Castration: From Stallion to Gelding. AAEP. https://old.aaep.org/horsehealth/castration-stallion-gelding Last accessed September 19, 2024.
  3. Robert MP, Chapuis RJJ, de Fourmestraux C, Geffroy OJ. Complications and risk factors of castration with primary wound closure: Retrospective study in 159 horses. Can Vet J. 2017 May; 58(5): 466–471. https://pubmed.ncbi.nlm.nih.gov/28487590/ Last accessed September 19, 2024.
  4. Shoemaker R, Bailey J, Janzen E, Wilson DG. Routine castration in 568 draught colts: incidence of evisceration and omental herniation. Equine Vet Jour 05 January 2010 https://doi.org/10.2746/0425164044890625 Last accessed September 19, 2024.
  5. Green P. Castration techniques in the horse. In Practice 2001;23:250-260. https://doi.org/10.1136/inpract.23.5.250 Last accessed September 19, 2024.
  6. Mason BJ, Newton JR, Payne RJ, Pilsworth RC. Costs and complications of equine castration: a UK practice based study comparing standing nonsutured and recumbent sutured techniques. Equine Vet J 2005;37:468-472. https://www.ncbi.nlm.nih.gov/pubmed/16163951 Last accessed September 19, 2024.
  7. Moll DH, Pelzer KD, Pleasant RS, Modranski PD. A survey of equine castration complications. J Equine Vet Sci 1995;15:522-
    526.
    https://www.sciencedirect.com/science/article/pii/S0737080607804217 Last accessed September 19, 2024.
  8. Code of Practice for the Care and Handling of Equines. National Farmed AnimalHealth and Welfare Council 2013. https://www.nfacc.ca/codes-of-practice/equine  Last accessed September 19, 2024.
  9. Heleski C, Cinq-Mars D, Dowling T, Merkeis L, Stampfli H, Yue Cottee S, de Wit J.Code Of Practice For The Care And Handling Of Equines: Review Of ScientificResearch On Priority Issues. July 2012. Equine Code of Practice Scientists’Committee. https://files.thehorseportal.ca/portal/uploads/2024/08/Equine_SCReport_Aug23.pdf   Last accessed September 19, 2024.
  10. Searle D, Dart AJ, Dart CM, Hodgson DR. Equine castration: review of anatomy,approaches, techniques and complications in normal, cryptorchid and monorchidhorses. Aust Vet J 1999;77:428-434. Availablefrom: https://www.ncbi.nlm.nih.gov/pubmed/10451725  Last accessedSeptember 19, 2024.
  11. Coutu P, Caulkett N, Pang D, Boysen S. Efficacy of a portable oxygenconcentrator with pulsed delivery for treatment of hypoxemia during equine fieldanesthesia. Vet Anaesth Analg. 2015 Sep;42(5):518-26. https://pubmed.ncbi.nlm.nih.gov/25683480  Last accessed September 19, 2024
  12. CVMA Position Statement Pain Management in Animals. February 22,2022. https://www.canadianveterinarians.net/policy-and-outreach/position-statements/statements/pain-management-in-animals-previously-pain-control-in-animals/  Last accessed September 19, 2024
  13. Muir WW. Pain therapy in horses. Equine Vet J 2005;37:98-100. https://doi.org/10.2746/0425164054223831  Last accessed September 19,2024.
  14. Love EJ, Taylor PM, Clark C, Whay HR, Murrell J. Analgesic effect of butorphanolin ponies following castration. Equine Vet J 2009;41:552-556. https://www.ncbi.nlm.nih.gov/pubmed/19803050  Last accessed September 19, 2024.
  15. CVMA Position Statement Surgical Procedures Performed on Animals, January22, 2021. https://www.canadianveterinarians.net/policy-and-outreach/position-statements/statements/surgical-procedures-performed-on-animals / Last accessed September 19, 2024