CVMA-ACMV

Pest Control – Position Statement

July 16, 2014

Position

The Canadian Veterinary Medical Association recognizes that lethal and non-lethal pest control measures may need to be used against nuisance animals to reduce damage or conflict, promote sustainable agricultural production, control diseases, and/or to ensure the conservation of biodiversity.  Such measures should be humane, scientifically based, have minimal environmental or human health impacts, and abide by local legislative and municipal requirements.  

Background

  1. Historically, the welfare of nuisance animals has received little attention, while the economic and ecological impact has been more widely researched.   There is a greater shift globally to consider welfare implications of pest control measures on these animals (1-8).
  2. Nuisance animals include overabundant or unwanted wildlife or feral animals, and vertebrate and invertebrate pests, which are controlled for reasons related to the protection of humans, animals, and/or the environment (2,4,9).
    1. The Canadian Pest Control Product Act defines a “pest” as an animal, a plant or other organism that is injurious, noxious or troublesome, whether directly or indirectly, and an injurious, noxious or troublesome condition or organic function of an animal, a plant or other organism (9).
    2. Awareness and adherence to federal, provincial, and municipal laws is required when undertaking any control measures against nuisance animals.
  3. Integrative pest management (IPM) programs should be adopted as a first line measure to reduce the need for the control of nuisance species (10-12).  This includes, but is not limited to:
    1. Actively identifying potential pest problems before they become an issue, with proactive planning and management of environments to prevent or deter organisms from becoming nuisance animals or pests.
    2. Monitoring populations of nuisance and beneficial organisms, quantifying the damages done by them, and evaluating for ecological changes associated with them.
    3. Establishing threshold levels, including the risk of infectious diseases, through which pest control measures will be implemented to reduce pest populations to acceptable levels.  In rare cases this may mean extirpation of an invasive species.
    4. Continuous evaluation and refinement of pest management strategies based on humane and ethical considerations, health and safety considerations, environmental impact, and overall effectiveness.
    5. Evaluation of outcomes if pest management procedures were not implemented.
  4. Effective pest control utilizes strategies that may include a combination of biological, physical, mechanical, cultural, behavioural, and chemical controls. (2,4,7,8,10,13-20).
    1. The welfare implications, safety, and ecological impact of the chosen strategy should always be considered. 
    2. Non-lethal methods should be evaluated and implemented whenever feasible.
      1. Examples of non-lethal pest control methods include installation of physical barriers; elimination of food sources; harbourage removal; repellants and deterrents (biological, chemical, physical); fertility control; vaccination against infectious diseases; and use of humane live traps with subsequent release.
      2. Factors to consider when using non-lethal methods that may have a negative welfare impact include restraint time; the effects of exposure or dehydration; pain; anxiety, fear, and/or distress; the long-term impact of injuries; and inadequate or unfamiliar food resources or shelter in a translocation site. (14,16,18,20,21)
      3. The ecological impact of some non-lethal methods should be considered before implementation.  For example, disease transmission may result from trapping and translocation of nuisance species.
    3. When lethal methods are used, the most humane method(s) should be selected, and every reasonable effort made to limit adverse ecological impact(s).
      1. The CVMA holds that when animals are killed for humane reasons, death must be quick using a method that causes the least possible pain and distress (22).
      2. Examples of lethal pest control methods include shooting; hunting; electrocution; kill traps, nets, and snares; collapsing of burrows with explosives; introduction of predators or disease; and the use of chemicals such as poisons and gases (2,4,5,7,8,10,11,19,24,25)
      3. When chemical methods are used, the potential detrimental primary and secondary effects on non-target species need to be considered.  They may not always be directly lethal to non-target species but may otherwise compromise reproduction, immune function, overall fitness, and longevity. (9-11,18).
  5. The use of inhumane methods of pest control should not be condoned (3,4,7,11,18,26).
    1. Examples of physical methods include “denning” (pouring kerosene into a den and igniting) to control coyotes and wolves; drowning, and the use of sticky boards for rodent control.
    2. The ingestion of some pesticides [e.g., strychnine, Compound 1080 (sodium fluoroacetate), Avitrol (4-Aminopyridine), and Furadan (flowable carbofuran)], results in severe pain, uncontrollable seizures, and death by asphyxiation.
    3. Commonly used rodenticides (anticoagulants, zinc phosphide, cholecalciferol analogues) are not considered humane as they cause considerable direct physiologic damage, prolonged suffering, and/or pain.
  6. The CVMA advocates for the development of species-specific Codes of Practice and standardized operating procedures for pest control measures.   The CVMA supports further research and refinement of pest control measures, including objective model and matrices development to evaluate humaneness using available scientific information and informed judgment, to improve the welfare of nuisance animals when they are managed.

References

1. Bracke MBM. Providing cross-species comparisons of animal welfare with a scientific basis.  Njas-Wagen J Life Sc 2006;54:61-75.

2. Littin KE. Animal welfare and pest control: meeting both conservation and animal welfare goals. Anim Welfare. 2010; 19 (2):171-176.

3. Littin, KE, Mellor, DJ. Strategic animal welfare issues: Ethical and animal welfare issues arising from the killing of wildlife for disease control and environmental reasons. Rev Sci Tech Off Int Epi 2005;24:767-782.

4. Littin KE, Mellor D, Warburton B, Eason CT. Animal welfare and ethical issues relevant to the humane control of vertebrate pests. N Z Vet J 2004;52:1-10.

5. Marks CA. Ethical issues in vertebrate pest control: Can we balance the welfare of individuals and ecosystems? In: Mellor DJ, Monamy V,eds. The Use of Wildlife in Research 1999:79-89.

6. Mellor DJ, Littin KE. Using science to support ethical decisions promoting humane livestock slaughter and vertebrate pest control. Anim Welfare 2004;13:S127-132.

7. Mason G, Littin KE. The humaneness of rodent pest control. Anim Welfare 2003;12:1-37.

8. UFAW. Guiding Principles in the Humane Control of Rats and Mice. [Online]. Available from: http://www.ufaw.org.uk/rodents.php Last accessed August1, 2014.

9. Government of Canada. Pest Control Products Act.  Justice Laws Website. 2006. Available from: http://laws-lois.justice.gc.ca/eng/acts/P-9.01/page-1.html#h-1 Last accessed August 1, 2014.

10. Braysher M. Managing vertebrate pests: Principles and strategies. Bureau of Resource Sciences, Australian Government Printing Service. 1993:58pp.

11. Sharp T, Saunders G. A model for assessing the relative humaneness of pest animal control methods.  Australian Government Department of Agriculture, Fisheries and Forestry, Canberra, ACT. 2008. Available from: http://www.daff.gov.au/animal-plant-health/welfare/aaws/humaneness-of-pest-animal-control-methods  Last accessed August 1, 2014.

12. Broom DM. The welfare of vertebrate pests in relation to their management. In: Cowan DP, Feare CJ, eds. Advances in Vertebrate Pest Management. Fürth, German: Flander Verlag, 1999:309-329.

13. DEFRA (2005). Review of effectiveness, environmental impact, humaneness and feasibility of lethal methods for badger control. A report to European Wildlife Division, Defra, 20 October, 2005. Department for Environment, Food and Rural Affairs, UK, London, viewed 19th July, 2007. Available from:  http://www.bovinetb.info/docs/Review-of-effectiveness-environmental-impact-humaneness-and-feasibility-of-lethal-methods-for-badger-control.pdf Last accessed August 1, 2014.

14. Engeman RM, Krupa HW, Kern J. On the use of injury scores for judging the acceptability of restraining traps. J Wildl Res 1997;2:124-127.

15.  Gregory N. Assessing the humaneness of pest control methods. In: Jones B, ed. Solutions for Achieving Humane Pest Animal Control. RSPCA Australia Scientific Seminar.  Australian War Memorial, Canberra. 2003:66-85.

16. Iossa G, Soulsbury CD, Harris S. Mammal trapping: A review of animal welfare standards of killing and restraining traps. Anim Welfare 2007;16:335-352.

17. Marks CA, Allen L, Gigliotti F, et al. Evaluation of the tranquilliser trap device (TTD) for improving the humaneness of dingo trapping. Anim Welfare 2004;13:393-399.

18. O’Connor CE. Welfare assessment of vertebrate toxic agents.  Surveillance 2004;31:19-20.

19. Morriss GA, Warburton  B,  Ruscoe  WA.  Comparison of the capture efficiency of a kill-trap set for brushtail possums that excludes ground-birds, and ground set leg-hold traps. New Zeal J of Zool 2000;27:201-206.

20. Schutz KE, Agren E, Amundin M, Röken B, Palme R, Mörner T. Behavioural and physiological responses of trap-induced stress in European badgers. J Wildl Manage. 2006; 70: 884-891.

21. White, PJ, Kreeger, TJ, Seal, US, et al. Pathological responses of red foxes to capture in box traps. J Wildl Manage 1991;55:75-80.

22.  CVMA. Euthanasia. Position Statement. Canadian Veterinary Medical Association, Ottawa, Ontario, 2014.

23. Warburton B, Orchard I.  Evaluation of five kill traps for effective capture and killing of Australian brushtail possums (Trichosurus vulpecular). New Zeal J Zool 1996;23:307-314.

24. Warburton B, Gregory N G, Morriss G. Effect of jaw shape in kill-traps on time to loss of palpebral reflexes in brushtail possums. J Wildl Dis 2000;36:92-96.

25. Woodroffe R, Bourne FJ, Cox DR, et al. Welfare of badgers (Meles meles) subjected to culling: Patterns of trap-related injury. Anim Welfare 2005;14:11-17.

26. Sherley M.  Is sodium fluoroacetate (1080) a humane poison?  Anim Welfare 2007;16:449-458.

(Revised July 2014)