Position Statements

Castration of Cattle, Sheep, and Goats

August 21, 2019

Position

The Canadian Veterinary Medical Association (CVMA) recommends that when castration of cattle, sheep, or goats is required, an appropriate technique with anesthesia and analgesia is used and that it is undertaken at a young age.

Summary

All methods of castration cause acute and chronic pain. This can be mitigated by the use of local anesthesia and an appropriate non-steroidal anti-inflammatory drug.

Background

  1. The CVMA encourages development and implementation of practical analgesic and anaesthetic protocols for ruminant castration that control acute and long-term pain, discomfort, and distress associated with this procedure.
  2. Castration of cattle, sheep, and goats has traditionally been a routine part of livestock husbandry. It avoids unwanted pregnancies and reduces aggression towards humans and other animals. Castration can improve meat quality by increasing the distribution of fat, improving tenderness (cattle and sheep) (1,2), avoiding undesirable odours and flavour (rams and goats) (3,4), and reducing the occurrence of dark-firm-dry meat (cattle) (5). However, intact animals are more efficient at converting feed into lean meat (6) and castration is not necessary for all systems of management, such as the rearing of lambs for slaughter before they reach sexual maturity and in veal cattle production.
  3. The development of alternative methods of castration, such as immunocastration, could potentially provide the production and meat quality desired in castrated ruminants without inflicting the suffering associated with current methods of castration (7,-9).
  4. Castration is performed by surgical removal of the testicles, or by techniques that cause restriction of the blood supply and testicular necrosis (e.g., rubber rings, bands, and Burdizzo/clamp) (10,11). Castration without anaesthesia and analgesia causes acute and chronic pain (12-14). Depending on the methods used, there is also a risk of complications, such as infection, fly strike, and haemorrhage (11). The risk of incomplete castration is lowest after surgery; it is intermediate after the use of a rubber ring, and greatest after the use of a Burdizzo/clamp (10).
  5. The sensory pain pathways and cortical centres necessary for pain perception are present at birth, and young ruminants show pain responses to castration (15-17). Although further research is required on the effects of age on the relative severity of pain experienced by young ruminants in response to castration (18), castration of young animals involves less tissue injury, methods of handling and restraint are easier, there is less reduction in growth rate, and some behavioural and physiological responses are lower than in older animals (16-21).
  6. Regardless of age and method of castration, all ruminants benefit from multimodal approaches to pain control involving the use of local anaesthesia to reduce acute responses, and non-steroidal anti-inflammatory drugs (NSAIDs) and analgesic drugs, to reduce longer-term responses (22-26) including post-castration anorexia (27). The use of a-2 agonists, e.g., xylazine, can provide beneficial sedation and a short period of analgesia (28,29).
  7. The administration of local anaesthesia to calves does not in itself cause a significant plasma cortisol response, whereas, castration without the use of local anaesthesia, clearly does (30). When there is a reluctance to use multimodal drugs, administration of an NSAID or if available, a topical anaesthetic is preferable to no pain control (31-33), but results are inconsistent (34-36), and these options do not provide optimal pain mitigation.
  8. Although not all National Farm Animal Care Council (NFACC) Codes of Practice (37) currently require the use of anaesthesia and analgesia for castration of all ages of ruminants, the CVMA holds that economic considerations (38), such as the costs of providing analgesic drugs, trained personnel and extra handling (24) should not influence the use of pain control for castration. When establishing a Veterinarian-Client-Patient-Relationship (VCPR) with a new client or reviewing castration procedures on an existing client's farm, the CVMA encourages veterinarians to (a) ensure that their clients are trained in the appropriate methods to use for castration (39), how to provide pain control, and how to recognize acute and chronic pain (14); and (b) make appropriate pain control drugs available for their clients to use when they themselves are castrating animals (40).
  9. Castration should only be carried out by competent personnel using appropriate, well-maintained equipment and accepted techniques with anaesthesia and analgesia, and subsequent monitoring for haemorrhage and infection.

References

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  13. Molony V, Kent JE, Robertson IS. Assessment of acute and chronic pain after different methods of castration of calves. Appl Anim Behav Sci 1995;46:33-48. Available from: http://www.sciencedirect.com/science/article/pii/0168159195006354 Last accessed October 30, 2017.
  14. Molony V, Kent JE. Assessment of acute pain in farm animals using behavioral and physiological measurements. J Anim Sci 1997;75:266-272. Available from: https://www.ncbi.nlm.nih.gov/pubmed/9027575 Last accessed October 30, 2017.
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  18. Johnson CB, Sylvester SP, Stafford KJ, Mitchinson SL, Ward RN, Mellor DJ. Effects of age on the electroencephalographic response to castration in lambs anaesthetized with halothane in oxygen from birth to 6 weeks old. Vet Anaesth Analg 2009;36:273-279. Available from: https://www.ncbi.nlm.nih.gov/pubmed/19397779 Last accessed October 30, 2017.
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