CVMA-ACMV

Castration of Piglets – Position Statement

September 21, 2016

Position

The Canadian Veterinary Medical Association (CVMA) holds that surgical castration of piglets to prevent boar-taint and aggression in post-pubertal boars is a painful procedure at any age and effective anesthesia and analgesia is required for all ages of pigs. The CVMA encourages development and implementation of practical analgesic and anesthetic protocols for, and alternatives to, swine castration. 

Summary

  • Castration of piglets is used to help avoid unwanted behaviour and prevent some quality issues in pork.

    Castration is a painful procedure.

    Effective pain management involving analgesia and/or anesthesia is required.

    Veterinarians should provide training to producers.

    Alternatives to surgical castration exist.

Background

  1. In North America, hogs are marketed between 5 and 6 months of age at approximately 120 kg live weight (265 lb). Intact market weight boars are post-pubescent and sexual activity and aggression can cause injury, pain, and discomfort. Castration of piglets is a method of avoiding unwanted post-pubertal behaviour and controlling boar taint, an unpleasant odour and flavour of cooked pork.
  1. Commonly, surgical castration of piglets is performed by producers. This surgical procedure is acutely painful and involves the incision of skin and manipulation of sensitive tissues with subsequent inflammation (1-3). There is a risk of haemorrhage, infection, and evisceration (4).
  1. Discomfort post-castration can last for 2 days (5). Local anesthetic injected into the testis and subcutaneously into the scrotum reaches the spermatic cord within minutes (6) and can reduce some of the responses to castration (7,8).
  1. Although there is no effect of age on the responses of piglets to the pain of castration (9), the revised code of practice for producers requires the administration of analgesia for castration of all ages, and anesthesia and analgesia for piglets older than 10 days of age (10).
  1. Some non-steroidal anti-inflammatory drugs (NSAIDS) have been approved for use in piglets in Canada and can reduce post-operative pain responses (11). The CVMA recognizes that pig producers incur additional expense owing to the cost of pain medication and time taken to administer.
  1. The administration of only analgesia (rather than effective anesthesia and analgesia) is less time-consuming than administering local anesthesia and waiting for it to take effect (12). Although the strength of the evidence has been questioned (13) and there is stress associated with extra handling and the administration of the local anesthetic (2), the administration of both local anesthesia and analgesia is necessary to effectively reduce the pain response during and after surgical castration (14-16).
  1. Veterinarians should provide training to producers on the recognition of cryptorchidism and herniation, and appropriate handling, surgical procedures, and anesthetic and analgesia protocols to follow when undertaking castration.
  1. Alternatives to surgical castration exist in Canada, including immunocastration (12) and raising intact male pigs marketed prior to sexual maturation.
     

References

  1. Taylor AA, Weary DM. Vocal responses of piglets to castration: Identifying procedural sources of pain. Appl Anim Behav Sci 2000;70:17-26.
  1. von Borell E, Baumgartner J, Giersing M, et al. Animal welfare implications of surgical castration and its alternatives in pigs. Animal 2009;3:1488-1496.
  1. Rault J, Lay DC,Jr., Marchant-Forde JN. Castration induced pain in pigs and other livestock. Appl Anim Behav Sci 2011;135:214-225
  1. St Jean G. Male reproductive surgery. The Veterinary Clinics of North America. Food animal practice. 1995;11:55-93.
  1. Hay M, Vulin A, Génin S, Sales P, Prunier A. Assessment of pain induced by castration in piglets: Behavioral and physiological responses over the subsequent 5 days. Appl Anim Behav Sci 2003;82:201-218.
  1. Ranheim B, Haga HA, Ingebrigtsen K. Distribution of radioactive lidocaine injected into the testes in piglets. J Vet Pharmacol Ther 2005;28:481-483.
  1. McGlone JJ, Hellman JM. Local and general anesthetic effects on behavior and performance of two- and seven-week-old castrated and uncastrated piglets. J Anim Sci 1988;66:3049-3058.
  1. Kluivers-Poodt M, Houx BB, Robben SRM, Koop G, Lambooij E, Hellebrekers LJ. Effects of a local anaesthetic and NSAID in castration of piglets, on the acute pain responses, growth and mortality. Animal 2012;6:1469-1475.
  1. McGlone JJ, Nicholson RI, Hellman JM, Herzog DN. The development of pain in young pigs associated with castration and attempts to prevent castration-induced behavioral changes. J Anim Sci 1993;71:1441-1446.
  1. National Farm Animal Care Council. Code of practice for the care and handling of pigs. National Farm Animal Care Council, 2014.
  1. Dzikamunhenga RS, Anthony R, Coetzee J, et al. Pain management in the neonatal piglet during routine management procedures. Part 1: A systematic review of randomized and non-randomized intervention studies. Animal Health Research Reviews, 2014;15:14-38.
  1. de Roest K, Montanari C, Fowler T, Baltussen W. Resource efficiency and economic implications of alternatives to surgical castration without anaesthesia. Animal 2009;3:1522-1531.
  1. O'Connor A, Anthony R, Bergamasco L, et al. Pain management in the neonatal piglet during routine management procedures. Part 2: Grading the quality of evidence and the strength of recommendations. Animal Health Research Reviews, 2014;15:39-62.
  1. Keita A, Pagot E, Prunier A, Guidarini C. Pre-emptive meloxicam for postoperative analgesia in piglets undergoing surgical castration. Vet Anaesth Analg 2010;37:367-74.
  1. Hansson M, Lundeheim N, Nyman G, Johansson G. Effect of local anaesthesia and/or analgesia on pain responses induced by piglet castration. Acta Vet Sc 2011;53:34-34.
  1. Pig Code of Practice Scientific Committee. Code of Practice for the Care and Handling of Pigs: Review of Scientific Research on Priority Issues. Lacombe (Alberta): National Farm Animal Care Council, 2012.

 

(Revised July 2016)