Register      Login
Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats
Shopping Cart: ( empty )
You are here: Home > Journals > WR > WR09009
RESEARCH ARTICLE
Contents Vol 36(8)

Behaviour and time to unconsciousness of brushtail possums (Trichosurus vulpecula) after a lethal or sublethal dose of 1080

Kate E. Littin A B F , Neville G. Gregory C , Andrea T. Airey D , Charles T. Eason D E and David J. Mellor A
+ Author Affiliations
- Author Affiliations

A Animal Welfare Science and Bioethics Centre, Massey University, Palmerston North, New Zealand.

B Present address: Animal Welfare Directorate, Ministry of Agriculture and Forestry, PO Box 2526, Wellington 6140, New Zealand.

C Royal Veterinary College, Hertfordshire, United Kingdom.

D Landcare Research, Lincoln, New Zealand.

E Current address: Lincoln University, PO Box 84, Lincoln, New Zealand.

F Corresponding author. Email: kate.littin@maf.govt.nz

Wildlife Research 36(8) 709-720 https://doi.org/10.1071/WR09009
Submitted: 26 January 2009  Accepted: 7 September 2009   Published: 16 December 2009

Abstract

Context. Sodium fluoroacetate (1080) is a vertebrate pesticide used in several countries, including New Zealand, where it is the main pesticide for controlling brushtail possums (Trichosurus vulpecula) – a significant agricultural and conservation pest. There is growing concern internationally about the impacts of vertebrate pesticides, including 1080, on pest animal welfare.

Aims. Behavioural changes and time to loss of consciousness of possums after 1080 ingestion in carrot baits were determined to compare the animal welfare impacts with other possum pesticides.

Methods. Eight lethally dosed possums and eight that consumed a dose intended to be sublethal were observed until death or recovery but not handled. Another nine lethally dosed possums were handled to determine responses to stimuli, indicating time to loss of consciousness.

Key results. Unhandled, lethally dosed possums died after 11 h 26 min ± 1 h 55 min (mean ± s.e.m.). Half had abnormal appearances and postures 1 h 50 min ± 9 min after consuming baits. Seven showed retching, and three vomited, over 27 ± 12 min from 2 h 53 min ± 13 min. Lack of coordination began 3 h 37 min ± 32 min after dosing, then possums spent most of the time until death lying, showing spasms and tremors. Five showed seizures while lying prostrate. Possums receiving a nominally sublethal dose all showed signs of poisoning, including abnormal postures, lethargy, lack coordination, retching, spasms or tremors, and a cessation of grooming, feeding and activity. One died 18 h 15 min after dosing, experiencing two seizures within 30 min of death. Response to handling, indicating total loss of consciousness, was lost in two possums before death.

Conclusions. Possums ingesting a lethal dose of 1080 experienced ~9.5 h of changed behaviour and lost consciousness close to death, although awareness was likely reduced sometime beforehand. Possums ingesting a nominally sublethal dose experienced some effects of poisoning.

Implications. These impacts are intermediate compared with other possum pesticides in New Zealand. Nevertheless, the potential for consciousness during and after retching and seizures is undesirable for animal welfare. Further work is encouraged on alternatives to 1080 and means of reducing its impact on animal welfare.

Additional keywords: animal welfare, brushtail possum, carrot bait, lethal dose, 1080, sodium fluoroacetate, sublethal dose.


Acknowledgements

This work was funded by the Agricultural and Marketing Research and Development Trust (AGMARDT) (9552), and the Foundation for Science, Research and Technology, New Zealand (CO9632). Lynne Milne made an invaluable contribution to the design and running of the experiment. The studies could not have been conducted without the support and assistance of Landcare Research Animal Facility staff.


References

Bell, J. (1972). The acute toxicity of four common poisons to the opossum, Trichosurus vulpecula. New Zealand Veterinary Journal 20, 212–214.
|  CAS | PubMed | Cooper D. , Larsen E. , and Shields J. (2007). 1080 and wildlife: scientific and ethical issues raised by its use on Australian animals. In ‘Pest or Guest: The Zoology of Overabundance’. (Eds D. Lunney, P. Eby, P. Hutchings and S. Burgin.) pp. 229–232. (Royal Zoological Society of New South Wales: Sydney.)

Cowan P. E. (2005). Brushtail possums. In ‘The Handbook of New Zealand Mammals’. (Ed. C. M. King.) pp. 56–80. (Oxford University Press: Melbourne.)

Cowled B. , and O’Connor C. (2004). A project that investigates current options for managing feral pigs in Australia and assesses the need for the development of more effective and humane techniques and strategies – Stage 3 Report. Pest Animal Control Cooperative Research Centre, Canberra.

Cowled, B. D. , Gifford, E. , Smith, M. , Staples, L. , and Lapidge, S. J. (2006). Efficacy of manufactured PIGOUT_ baits for localised control of feral pigs in the semiarid Queensland rangelands. Wildlife Research 33, 427–437.
| Crossref | GoogleScholarGoogle Scholar | DWRC (Denver Wildlife Research Center) (1989). Compound 1080 grain bait assay. Method No. 8B, May 1989. DWRC, Denver, CO.

Eason C. T. , and Wickstrom M. (2001). Vertebrate pesticide toxicology manual (poisons): information on poisons used in New Zealand as vertebrate pesticides. Department of Conservation Technical Series 23. Department of Conservation, Wellington, New Zealand.

Eason C. T. , Warburton B. , and Henderson R. (2000). Toxicants used for possum control. In ‘The Brushtail Possum: Biology, Impact and Management of an Introduced Marsupial’. (Ed. T. L. Montague.) pp. 154–163. (Manaaki Whenua Press: Lincoln, New Zealand.)

Fonnum, F. , Johnsen, A. , and Hassel, B. (1997). Use of fluorocitrate and fluoroacetate in the study of brain metabolism. Glia 21, 106–113.
| Crossref | GoogleScholarGoogle Scholar | CAS | PubMed | Gregory G. (1996). Perception of pain associated with 1080 poisoning. In ‘Humaneness of Vertebrate Pest Control – Proceedings of the Seminar Held 27th March, 1996’. Report series no. 2. (Eds P. M. Fisher and C. A. Marks.) pp. 62–64. (Victorian Institute of Animal Science: Melbourne.)

Gregory N. G. , Eason C. T. , and Warburton B. (1996). Welfare aspects of possum control. In ‘Improving Conventional Control of Possums’. The Royal Society of New Zealand Miscellaneous Series 35. pp. 18–21. (The Royal Society of New Zealand: Wellington, New Zealand.)

Gregory, N. G. , Milne, L. M. , Rhodes, A. T. , Littin, K. E. , Wickstrom, M. , and Eason, C. T. (1998). Effect of potassium cyanide on behaviour and time to death in possums. New Zealand Veterinary Journal 46, 60–64.
|  CAS | PubMed | Johnston S. A. (1996). Physiology, mechanisms, and identification of pain. In ‘Predictable Pain Management: New Approaches to Analgesia, Anesthesia, and Sedation. Proceedings of the North American Veterinary Conference, Orlando, FL’. pp. 5–11.

Largo, C. , Cuevas, P. , Somjen, C. G. , del Rio, M. , and Herreras, O. (1996). The effect of depressing glial function in rat brain in situ on ion homeostasis, synaptic transmission and neuron survival. The Journal of Neuroscience 16, 1219–1229.
|  CAS | PubMed | Littin K. E. (2004). The behaviour, pathophysiology and pathology of brushtail possums (Trichosurus vulpecula) poisoned with 1080 or brodifacoum, and the implications for possum welfare. Ph.D. Thesis, Massey University, Palmerston North.

Littin, K. E. , O’Connor, C. E. , Gregory, N. G. , Mellor, D. J. , and Eason, C. T. (2002). Behaviour, coagulopathy and pathology of brushtail possums (Trichosurus vulpecula) poisoned with brodifacoum. Wildlife Research 29, 259–267.
| Crossref | GoogleScholarGoogle Scholar | Morgan D. R. , and Hickling G. J. (2000). Techniques used for poisoning possums. In ‘The Brushtail Possum: Biology, Impact and Management of an Introduced Marsupial’. (Ed. T. L. Montague.) pp. 143–153. (Manaaki Whenua Press: Lincoln, New Zealand.)

Morgan, D. R. , and Milne, L. (2002). Cholecalciferol-induced bait shyness in possums (Trichosurus vulpecula). International Journal of Pest Management 48, 113–119.
| Crossref | GoogleScholarGoogle Scholar | CAS | Osweiler G. D. , Carson T. L. , Buck W. B. , and van Gelder G. A. (1985). Fluoroacetate and fluoroacetamide. In ‘Clinical and Diagnostic Veterinary Toxicology’. 3rd edn. pp. 340–344. (Kendall Hunt: Dubuque, IA.)

Pelfrene A. F. (1991). Chapter 19: synthetic organic rodenticides. In ‘Handbook of Pesticide Toxicology’. (Eds W. J. Hayes, Jr. and E. R. Laws, Jr.) pp. 1271–1316. (Academic Press: London.)

Peters, R. A. , Spencer, H. , and Bidstrup, P. L. (1981). Subacute fluoroacetate poisoning. Journal of Occupational Medicine 23, 112–113.
| Crossref | GoogleScholarGoogle Scholar | CAS | PubMed | Rammell C. G. , and Fleming P. A. (1978). ‘Compound 1080: Properties and Use of Sodium Monofluoroacetate in New Zealand.’ Ministry of Agriculture and Fisheries Animal Health Division, Wellington, New Zealand.

Reigart, J. R. , Brueggeman, J. L. , and Keil, J. E. (1975). Sodium fluoroacetate poisoning. American Journal of Diseases of Children 129, 1224–1226.
|  CAS | PubMed | Schimelpfenig T. , and Lindsey L. (2000). Cold injuries. In ‘Wilderness First Aid’. 3rd edn. pp. 132–159. (National Outdoor Leadership School/Stackpole Books: Mechanicsburg, PA.)

Sharp T. , and Saunders G. (2004). Model code of practice for the humane control of feral pigs. NSW Department of Primary Industries, Orange, NSW.

Sharp T. , and Saunders G. (2008). A model for assessing the relative humaneness of pest animal control methods. Australian Government Department of Agriculture, Fisheries and Forestry, Canberra, ACT. Available at www.daff.gov.au/__data/assets/pdf_file/0008/929888/humaneness-pest-animals.pdf [accessed 23 January 2009].

Sherley, M. (2004). The traditional categories of fluoroacetate poisoning signs and symptoms belie substantial underlying similarities. Toxicology Letters 151, 399–406.
| Crossref | GoogleScholarGoogle Scholar | CAS | PubMed | Williams D. (1996). Animal welfare aspects of the use of sodium monofluoroacetate to poison wild rabbits. In ‘Humaneness of Vertebrate Pest Control – Proceedings of the Seminar Held 27 March 1996’. (Eds P. M. Fisher and C. A. Marks.) pp. 37–42. (Victorian Institute of Animal Science: Melbourne.)