Pain Management in Animals (Previously Pain Control in Animals)

February 22, 2022


The Canadian Veterinary Medical Association (CVMA) holds that veterinarians have a duty to use appropriate pain management protocols for surgical procedures and for the treatment of medical conditions that result in or are likely to cause pain.


  • Animal pain and suffering are clinically important conditions that adversely affect health and quality of life.
  • The veterinary profession must apply the precautionary principle regarding an animal’s ability to experience pain and make recommendations regarding pain prevention and management accordingly.
  • The potential for pain in animals resulting from surgical procedures or medical conditions must always be considered, and pain must be prevented or treated as effectively as possible.
  • Veterinarians have the required knowledge and skill to prevent, eliminate, reduce, or mitigate pain.
  • Veterinarians must stay current in the recognition and management of pain in the species they treat.


  1. Pain is “an unpleasant sensory and emotional experience associated with actual or potential tissue damage” (1).
  2. Nociception is “a sensory ability to respond to damaging stimuli”. It is present in many species and can occur without an animal feeling pain.
  3. Many animals show physiological and behavioural responses to nociception similar to those that occur when humans experience pain. There is a lack of definitive evidence to determine the extent to which animals can experience pain; therefore, the ‘precautionary principle’ should be applied where the evidence leads to uncertainty (2). As a result, the veterinary profession must make recommendations regarding pain prevention and management as if all animals in their care are capable of experiencing pain.
  4. Pain and suffering are clinically important conditions that adversely affect an animal's health and quality of life, either in the short or long term (3).
  5. Veterinarians have a professional responsibility to be able to recognize pain and distress in multiple species and to stay current with new developments in pain prevention, recognition, and management (4,5). Species-typical responses to pain are increasingly well-described and the capacity of animals to experience pain should not be dismissed due to pain masking behaviour (6-19).
  6. Acute pain varies in severity from mild to severe, and can be induced by trauma, surgery, or disease. The intensity of acute pain following a tissue insult is usually greatest within the first 24 to 72 hours and frequently responds favorably to analgesic drugs (20).
  7. Chronic pain lasts from months to years and is pain that persists beyond the time usually required for an injury to heal and is associated with a chronic pathologic process.  It often requires long term administration of medication[s] as well as the modification of the animal’s environment, body condition, activity levels, and functional usage. Chronic pain may also respond favorably to non-pharmacological interventions (20).
  8. Neuropathic pain is chronic and originates from injury of the peripheral or central nervous systems.  Different causes include trauma (e.g., amputation and crushing injury), vascular injury (e.g., thromboembolic disease), endocrinopathy (e.g., diabetes mellitus), or infection (e.g., post-herpetic neuralgia) (21). Neuropathic pain often requires several classes of medications as it often cannot be adequately managed with a single pharmacological therapy (20).
  9. Successful management of surgical pain requires thoughtful planning of peri-operative analgesia to ensure effective pain relief is provided before, during, and after surgery. A multi-modal regimen may be required for higher intensity pain as a single class of analgesic may be inadequate. Sedation may be required to ensure stress and fear are minimised. While sedatives (e.g., phenothiazines, benzodiazepines) and general anesthetics (e.g., thiopental, propofol, inhalants) alter the perception of pain, they do not substantially alter nociceptive processing and should not be considered analgesic drugs (22, 23).
  10. The concurrent use of two or more pharmacologic classes of analgesic drugs (opioids, alpha-2 agonists, anti-inflammatories, local and regional anesthetics, dissociative anesthetics, and GABA analogues) generally provides more effective pain control, with fewer side-effects, than therapy with a single drug (24, 25). The potential for adverse side effects, which can occur when higher doses of a single agent are used, is also reduced (26, 27).
  11. Non-pharmacological pain management interventions should be implemented in addition to pharmacological interventions as part of a holistic pain management approach. These may include but are not limited to: environmental modification (e.g. access to conspecifics, quiet resting areas), rehabilitation therapy, manipulative medicine, cryotherapy, thermotherapy, acupuncture, therapeutic ultrasound and laser therapy.   The use of complementary and alternative medicine for pain control is considered in the CVMA Position Statement on Complementary and Alternative Veterinary Medicine (28).
  12. Currently, some anesthetic and analgesic drugs are licensed for use in companion animals, but fewer are licensed for use in livestock, research, or wild animals. The CVMA recognizes that there is an urgent need to approve anesthetic and analgesic drugs for food animal species, and to provide veterinarians and producers with appropriate withdrawal times for these drugs.  
  13. The CVMA supports quality assurance programs that promote humane treatment of all species through the prudent use of extra-label anesthetic and analgesic drugs. Given the current lack of anesthetic and analgesic drugs licensed for use in livestock and wild animals, the CVMA supports the responsible extra-label use of these drugs by veterinarians (29).  Additional information can be found on the CVMA Position Statement on Extra-label Drug Use (30)The CVMA also urges federal regulators to develop programs that facilitate approval of species-appropriate anesthetic and analgesic drugs, or to exempt most of these drugs from restrictions that unintentionally result in unnecessary animal pain.
  14. The CVMA holds that economic considerations, such as the costs of providing analgesic drugs, training personnel and extra handling must not influence the use of pain control for surgical procedures undertaken by producers and caretakers.
  15. The CVMA encourages veterinarians to (a) ensure that their clients or researchers who engage in approved potentially painful procedures on animals are fully trained in best techniques, how to provide pain control, and how to recognize acute and chronic pain; and (b) make appropriate pain control drugs available for their clients to use when clients are undertaking painful procedures (31).



  1. International Association for the Study of Pain, 2017. Available from: Last accessed September 2021.
  2. Sneddon LU, Elwood RW, Adamo SA, Leach MC. Defining and assessing animal pain. Anim Behav. 2014;97:201-212. doi:10.1016/j.anbehav.2014.09.007.
  3. American College of Veterinary Anesthesiologists. Position Paper on the Treatment of Pain in Animals (2006). Available from: Last accessed September 2021.
  4. Rollin BE.  Animal pain: What it is and why it matters. J Ethics. 2011; 15(4):425-437. Available from: p. Last accessed September 2021.
  5. Weary DM, Niel L, Flower FC, Fraser D. Identifying and preventing pain in animals. Appl Anim Behav Sci 2006;100:64-76.
  6. Diesch TJ, Mellor DJ, Johnson CB, Lentle RG. Responsiveness to painful stimuli in anaesthetised newborn and young animals of varying neurological maturity (wallaby joeys, rat pups and lambs). ALTEX 2007;14:549-552. Available from  logical_maturity_wallaby_joeys_rat_pups_and_lambs/links/00b7d528a7bc714e2d000000 /Responsiveness-to-painful-stimuli-in-anaesthetised-newborn-and-young-animals-of-vary ing-neurological-maturity-wallaby-joeys-rat-pups-and-lambs.pdf. Last accessed September 2021.
  7. Weber ES, 3rd. Fish analgesia: Pain, stress, fear aversion, or nociception? Vet Clin North Am Exot Anim Pract 2011;14:21-32.Weber ES, 3rd. Available from nalgesia-Pain-Stress-Fear-Aversion-or-Nociception.pdf. Last accessed September 2021.
  8. Evangelista, M.C., Watanabe, R., Leung, V.S.Y. et al. Facial expressions of pain in cats: the development and validation of a Feline Grimace Scale (2019). Available from: Last accessed September 2021.
  9. Langford, D. J. et al. Coding of facial expressions of pain in the laboratory mouse. Nat Methods 7, 447–449 (2010).
  10. C.Sotocinal, S. G. et al. The Rat Grimace Scale: A partially automated method for quantifying pain in the laboratory rat via facial expressions. Mol. Pain 7, 55 (2011). Available from: Last accessed September 2021.
  11. D.Keating, S. C. J., Thomas, A. A., Flecknell, P. A. & Leach, M. C. Evaluation of EMLA Cream for Preventing Pain during Tattooing of Rabbits: Changes in Physiological, Behavioural and Facial Expression Responses. PLoS One 7(9)(2012). Available from: Last accessed September 2021.
  12. E.Dalla Costa, E. et al. Development of the Horse Grimace Scale (HGS) as a pain assessment tool in horses undergoing routine castration. PLoS One 9, 1–10 (2014). Available from: Last accessed September 2021.
  13. F.McLennan, K. M. et al. Development of a facial expression scale using footrot and mastitis as models of pain in sheep. Appl. Anim. Behav. Sci. 176, 19–26 (2016).
  14. G.Hager, C. et al. The Sheep Grimace Scale as an indicator of post-operative distress and pain in laboratory sheep. PLoS One 12, e0175839 (2017). Available from Last accessed September 2021.
  15. H.Guesgen, M. J. et al. Coding and quantification of a facial expression for pain in lambs. Behav. Processes 132, 49–56 (2016).
  16. I. Di Giminiani, P. et al. The Assessment of Facial Expressions in Piglets Undergoing Tail Docking and Castration: Toward the Development of the Piglet Grimace Scale. Front. Vet. Sci. 3, 100 (2016). Available from Last accessed September 2021.
  17. J.Viscardi, A. V., Hunniford, M., Lawlis, P., Leach, M. & Turner, P. V. Development of a Piglet Grimace Scale to Evaluate Piglet Pain Using Facial Expressions Following Castration and Tail Docking: A Pilot Study. Front. Vet. Sci. 4, 51 (2017). Available from: Last accessed September 2021.
  18. K.Reijgwart, M. L. et al. The composition and initial evaluation of a grimace scale in ferrets after surgical implantation of a telemetry probe. PLoS One 12 (2017). Available from: Last accessed September 2021.
  19. L.Holden, E. et al. Evaluation of facial expression in acute pain in cats. J. Small Anim. Pract. 55, 615–621 (2014).
  20. World Small Animal Veterinary Association Global Pain Council Guidelines. Available from: Last accessed September 2021.
  21. Mathews, K., Kronen, P.W., Lascelles, D., Nolan, A., Robertson, S., Steagall, P.V., Wright, B. and Yamashita, K. (2014), Guidelines for Recognition, Assessment and Treatment of Pain. J Small Anim Pract, 55: E10-E68. Available from: accessed September 2021.
  22. Sandra Forsyth, BVSc, DACVA Perioperative Analgesia World Small Animal Veterinary Association World Congress Proceedings, 2003    Available from  Last accessed September 2021.
  23. Grimm, et al., 2015. Lumb and Jones’ Veterinary Anesthesia and Analgesia, Ames, Iowa, Wiley Blackwell publishing.
  24. Meintjes RA.  An overview of the physiology of pain for the veterinarian. Vet J. 2012; 193:3
  25. Coetzee JF. A review of analgesic compounds used in food animals in the United States. Vet lin North Am Food Anim Pract 2013;29:11-29.
  26. Dyson DH. Perioperative pain management in veterinary patients. Vet Clin North Am Small Anim Pract 2008;38:1309-1327.
  27. AAHA/AAFP Pain Management Guidelines Task Force. AAHA/AAFP Pain Management Guidelines for Dogs and Cats. J Amer Anim Hosp Asso 2007;43:235-248.2015. Available from: anagement_guidelines_for_dogs_and_cats.pdf. Last accessed September 2021.
  28. CVMA Position Statement on Complementary and Alternative Medicine (2019). Available from: icine-october-2019. Last accessed September 2021.
  29. Smith G.  Extralabel use of anesthetic and analgesic compounds in cattle. Vet Clin North Am Food Anim Pract 2013;29:29-45.
  30. CVMA Position Statement on Extra-Label Drug Use. Available from: CVMA | Documents | Off-Label Use of Drugs (UMDDE) – Position Statement ( Last accessed September 2021.
  31. Alsaaod M, Doherr MG, Greber D, Steiner A. Experience with the delegation of anaesthesia for disbudding and castration to trained and certified livestock owners. PMC Vet Res 2014;10:35. Available from: Last accessed September 2021.