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Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats
RESEARCH ARTICLE

Performance and humaneness of chloropicrin, phosphine and carbon monoxide as rabbit-warren fumigants

F. Gigliotti A , C. A. Marks B C and F. Busana A
+ Author Affiliations
- Author Affiliations

A Vertebrate Pest Research Unit, Department of Primary Industries Research Victoria, PO Box 48, Frankston, Vic. 3199, Australia.

B Nocturnal Wildlife Research Pty Ltd, PO Box 2126, Wattletree Road Post Office, East Malvern, Vic. 3145, Australia.

C Corresponding author. Email: camarks@attglobal.net

Wildlife Research 36(4) 333-341 https://doi.org/10.1071/WR06020
Submitted: 24 February 2006  Accepted: 12 March 2009   Published: 1 June 2009

Abstract

Concerns about the humaneness and efficacy of chloropicrin (CLPN) and phosphine (PH3) as warren fumigants for the control of European rabbits (Oryctolagus cuniculus) prompted this investigation into the field performance and humaneness of carbon monoxide (CO) as an alternative fumigant. Comparative trials were performed in a naturally formed 1.3-m3 warren fitted with gas, temperature and humidity sensors as well as infrared cameras and microphones. Trials used concentrations of 5% and 6% CO introduced at 400 L min−1, and standard field practices for CLPN and PH3. Rabbits exposed to CLPN displayed signs of intense irritation and extreme distress during a lethal toxicosis lasting a mean of 82.5 min, supporting previous conclusions that CLPN causes suffering. Phosphine gas killed 10 of 12 rabbits, in a mean of 225.3 min. This relatively poor performance was attributed to the low rate of gas production and passive diffusion through the warren, reflected in highly variable warren concentrations between trials. Phosphine caused greater agitation on the onset of first symptoms than did CO; however, the behavioural symptoms after collapse were broadly similar. Carbon monoxide dispersed evenly in the warren, caused no immediate irritation or distress and produced a gradual stupor before unconsciousness and death. Concentrations of 6% CO killed rabbits almost three times faster than 5% CO, suggesting that relatively small increments of concentration and exposure time are crucial in obtaining a consistently rapid death. A concentration of 6% CO caused death in 8 of 10 rabbits in a mean of 28.3 min; some 2.9 and 8 times faster than CLPN and PH3 respectively. The time from collapse until death did not appear to be appreciably different for PH3 and 6% CO. The present study demonstrated that CO has potential as a rapid-acting, humane and effective fumigant for rabbit control.


Acknowledgements

Special thanks go to the many contributors who freely gave their time and experience, including Dr Marc Marshall (Monash University), Peter Weare (hypobaric engineer), Darren Todd (Bosch Australia), Wim Vanden Hil (Allara), Tim Passmore (Air Liquide), Tony Ciaglia (Autlec), Jim Blight (AMCOSH), Frank Seabridge and Paul Hay. This study was funded by the Catchment and Water Division of the Department of Sustainability and Environment (Victoria). All research procedures were carried out in accordance with the Australian Code of Practice for the Care and Use of Animals for Scientific Purposes and were approved by the Primary Industries Research Victoria Metropolitan Animal Ethics Committee (AEC) as Protocol 2126. The use of CO in trials was in accordance with National Registration Authority (NRA) Permit No. TPM0015A. Many thanks go to Dr Kate Blaszak and the late Dr John Barnett for reading an earlier draft of this paper and providing constructive feedback. The paper benefited from comments received from three anonymous referees and helpful advice from Dr Andrea Taylor and other editorial staff at Wildlife Research.


References

Alonso, J. R. , Cardellach, F. , López, S. , Casademont, J. , and Miro, Ò. (2003). Carbon monoxide specifically inhibits cytochrome C oxidase of human mitochondrial respiratory chain. Basic & Clinical Pharmacology & Toxicology 93, 142–146.
CAS | Anon. (1984). ‘Verminpac: Wombats, Item 20.’ (Department of Conservation, Forests and Lands (Victoria): Melbourne.)

Anon. (1989). ‘The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals.’ (Merck & Co., Inc.: Whitehouse Station, NJ.)

Anon. (1999). ‘Rabbits: Methods of Fumigating Rabbit Burrows.’ (Natural Resources and Environment: Melbourne.)

Anon. (undated). ‘Phosphine, Occupational, Health and Safety Information.’ (World Health Organisation: New York.)

Buckley, L. A. , Jiang, X. Z. , James, R. A. , Morgan, K. T. , and Barrow, C. S. (1984). Respiratory tract lesions induced by sensory irritants at the RD50 concentrations. Toxicology and Applied Pharmacology 74, 417–429.
Crossref | GoogleScholarGoogle Scholar | CAS | PubMed | Clayton G. D. , and Clayton F. E. (1981). ‘Patty’s Industrial Hygiene and Toxicology.’ (Wiley: New York.)

Deng Z. , and Chang Z. U. (1986). Efficacy of a carbon monoxide gas cartridge against field rodents. In ‘Proceedings of the 12th Vertebrate Pest Conference’. (Eds R. E. Marsh and D. E. Beadle.) pp. 163–165. (University of California: Davis, CA.)

Enggaared-Hansen, N. , Creutzberg, A. , and Simonsen, H. B. (1991). Euthanasia of mink by carbon monoxide (CO), carbon dioxide (CO2) and nitrogen (N2). British Veterinary Journal 147, 140–146.
PubMed | Fisher P. M. and Marks C. A. (1996). ‘Humaneness and Vertebrate Pest Control.’ (Ropet Printing: Tynong North, Vic.)

Fuhr, I. , Bronsford, A. V. , and Silver, S. D. (1948). Sorption of fumigant vapours by soil. Science 107, 274–275.
Crossref | GoogleScholarGoogle Scholar | CAS | PubMed | Green C. J. (1982). ‘Laboratory Animals Handbook 8.’ (Laboratory Animals Ltd: London.)

Hart S. , Marks C. A. , and Staples L. M. (1996). Humane control of foxes (Vulpes vulpes) in natal dens. In ‘Proceedings of the Humaneness and Vertebrate Pest Control Seminar’. (Eds P. Fisher and C. A. Marks.) pp. 77–81. (Ropet Printing: Tynong North, Vic.)

Hayward, J. S. , and Lisson, P. A. (1978). Carbon dioxide tolerance of rabbits and its relation to burrow fumigation. Australian Wildlife Research 5, 253–261.
Crossref | GoogleScholarGoogle Scholar | Marks C. A. (1998). Review of the humaneness of destruction techniques used on the common wombat Vombatus ursinus in Victoria. In ‘Wombats’. (Eds R. T. Wells and P. A. Pridmore.) pp. 287–297. (Surrey Beatty: Sydney)

Marks C. A. (2003). What is possible to ensure that existing control methods are more humane? In ‘Solutions for Achieving Humane Vertebrate Pest Control’. Proceedings of the 2003 RSPCA Australia Scientific Seminar. (Ed. B. Jones.) pp. 85–94. (Royal Society for the Prevention of Cruelty to Animals, Australia: Canberra.)

Marks, C. A. (2009). Fumigation of rabbit warrens with chloropicrin produces poor welfare outcomes – a review. Wildlife Research 36, 342–352.
Crossref | GoogleScholarGoogle Scholar | Matschke G. H. , and Fagerstone K. A. (1984). Efficacy of a two ingredient fumigant for Richardsons ground squirrels. In ‘Proceedings of the 11th Vertebrate Pest Control Conference’. (Ed. D. O. Clark.) pp. 17–19. (University of California: Davis, CA.)

Moreland, A. F. (1974). Carbon monoxide euthanasia of dogs, chamber concentrations and comparative effects of automobile engine exhaust and carbon monoxide from a cylinder. Journal of the American Veterinary Medical Association 165, 853–855.
CAS | PubMed | Reilly J. (2001). ‘Euthanasia of Animals Used for Scientific Purposes.’ (ANZCCART: Adelaide.)

Rolls E. C. (1969). ‘They All Ran Wild.’ (Angus and Robertson: Sydney.)

Ross J. (1986). Comparisons of fumigant gases used for rabbit control in Great Britain. In ‘Proceedings of the 12th Vertebrate Pest Conference’. (Ed. T. P. Salmon.) pp. 153–157. (University of California: Davis, CA.)

Ross, J. , Page, R. J. C. , Nadian, A. K. , and Langton, S. D. (1998). The development of a carbon monoxide producing cartridge for rabbit control. Wildlife Research 25, 305–314.
Crossref | GoogleScholarGoogle Scholar | Rowsell H. C. , Ritcey J. , and Cox F. (1979). Assessment of humaneness of vertebrate pesticides. In ‘Proceedings of the Canadian Association of Laboratory Animal Science’. pp. 236–249. (Canadian Society for Laboratory Animal Science: Calgary.)

Salmon T. P. , and Bentley W. J. (1982). Aluminium phosphide (phostoxin) as a burrow fumigant for ground squirrel control. In ‘Proceedings of the 10th Vertebrate Pest Conference’. (Ed. R. E. Marsh.) pp. 143–146. (University of California: Davis, CA.)

Sangalli, B. C. , and Bidanset, J. H. (1990). A review of carboxymyoglobin formation: a major mechanism of carbon monoxide toxicity. Veterinary and Human Toxicology 32, 449–453.
CAS | PubMed | Saunders G. , Coman B. J. , Kinnear J. , and Braysher M. (1995). ‘Managing Vertebrate Pests: Foxes.’ (Australian Government Publishing Service: Canberra.)

Scott W. N. (1976). The use of poisons in animal destruction. In ‘Humane Destruction of Unwanted Animals’. pp. 33–42. (Universities Federation of Animal Welfare: Hertfordshire, UK.)

Sexton M. (1983). ‘Declared Animal Control.’ (Technical Publications Trust: Perth.)

Stewart, R. D. (1976). The effect of carbon monoxide on humans. Journal of Occupational Medicine. 18, 304–309.
Crossref | GoogleScholarGoogle Scholar | CAS | Williams K. , Parer I. , Coman B. , Burley J. , and Braysher M. (1995). ‘Managing Vertebrate Pests: Rabbits.’ (Government Publishing Service: Canberra.)