, Volume 24, Issue 5, pp 1087–1101 | Cite as

Assessment of toxicity and coagulopathy of brodifacoum in Japanese quail and testing in wild owls

  • Kirstin H. Webster
  • Kendal E. Harr
  • Darin C. Bennett
  • Tony D. Williams
  • Kimberly M. Cheng
  • France Maisonneuve
  • John E. Elliott


Based on detection of hepatic residues, scavenging and predatory non-target raptors are widely exposed to second generation anticoagulant rodenticides (SGARs). A small proportion, generally <10 %, of tested birds are diagnosed as acutely poisoned. Little is known, however, of sub-lethal effects of SGARs, such as interaction of clotting capacity with traumatic injury. Assessment of coagulation function of birds submitted live to wildlife rehabilitators or veterinarians may provide a means of establishing the proportion of animals suffering sub-lethal coagulopathies, as well as identifying individuals requiring treatment. As a first step in exploring the potential of this approach, we dosed Japanese quail (Coturnix japonica) with the SGAR, brodifacoum, at 0, 0.8, 1.4, 1.9, and 2.5 mg/kg and sampled birds at 1, 3, 5 and 7 days post-dosing. Prothrombin time (PT), which measures the extrinsic coagulation pathway, was significantly prolonged in 98 % of brodifacoum-exposed quail in a dose- and time-dependent manner. 50-fold prolongation of PT occurred at higher brodifacoum dosages and correlated to hemorrhage found at necropsy. Activated clotting time (ACT), a measure of the intrinsic pathway also increased with dose and time. Hemoglobin (Hb) and hematocrit (Hct) decreased dose- and time-dependently at doses ≥1.4 mg/kg with no significant change at 0.8 mg/kg. Reference intervals for PT (10.0–16.2 s), ACT (30–180 s), Hb (9.6–18.4 g/dl), and Hct (34–55 %) were established in Japanese quail. Species-specific reference intervals are required as barn owl PT (17–29 s) and quail PT were different. The proportion of brodifacoum-exposed quail with hemorrhage was not correlated with liver residues, but was correlated with PT, suggesting that this assay is a useful indicator of avian anticoagulant rodenticide exposure. PTs measured in free-living barn owls sampled between April 2009 and August 2010 in the lower Fraser Valley of BC do not suggest significant exposure to SGARs.


Brodifacoum Rodenticide Prothrombin time Japanese quail Biomarker Barn owl 



We wish to thank Sofi Hindmarch for support in the field and barn owl expertise. For brodifacoum analysis we would like to thank Brad McPherson at the Pacific Environmental Science Centre for analysis of the dosing solutions, and the National Wildlife Research Centre staff for liver residue analysis. For additional biostatistical analysis of PT and ACT data, we would like to thank Dave Cacela at Stratus Consulting. For initial coagulation assay work, we'd like to thank Courtney Albert. We would like to thank the staff at the University of British Columbia Animal Care Centre, specifically Gordon Gray, Dr. Tamara Godbey, for their assistance with the laboratory study. Funding was provided by Simon Fraser University, Canadian Wildlife Service and the Pesticide Science Fund of Environment Canada.

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical standards

All field protocols were conducted under necessary permits acquired from provincial, federal and institutional authorities.

Supplementary material

10646_2015_1449_MOESM1_ESM.xlsx (14 kb)
Supplementary material 1 (XLSX 14 kb)


  1. Albert CA, Wilson LK, Mineau P, Trudeau S, Elliott JE (2010) Anticoagulant rodenticides in three owl species from Western Canada, 1988-2003. Arch Environ Contam Toxicol 58:451–459CrossRefGoogle Scholar
  2. Bachmann KA, Sullivan TJ (1983) Dispositional and pharmacodynamic characteristics of brodifacoum in warfarin-sensitive rats. Pharmacology 27:281–288CrossRefGoogle Scholar
  3. Bailey C, Fisher P, Eason CT (2005) Assessing anticoagulant resistance in rats and coagulation effects in birds using small-volume blood samples. Sci Conserv 249:1–22Google Scholar
  4. Bateman SW, Mathews KA (1999) Comparison of axillary and heating block methods of activated clotting time (ACT) in dogs. J Vet Emerg Crit Care 9:79–82CrossRefGoogle Scholar
  5. Batten P, Bratt H (1990) Brodifacoum: Elimination From The Tissues Of Rats Following Administration Of Single Oral Doses. Unpubl. report submitted to EPA by ICI Americas, Inc., Wilmington, DE. 65 pp. In US EPA, 2004Google Scholar
  6. Berkner KL (2000) The vitamin K-dependent carboxylase. J Nutr 130:1877–1880Google Scholar
  7. Bigland CH, Triantaphyllopoulos DC (1961) Chicken prothrombin, thrombin, and fibrinogen. Am J Physiol 200:1013–1017Google Scholar
  8. Bigland CH (1964) Blood clotting time of five avian species. Poult Sci 43:1035–1039CrossRefGoogle Scholar
  9. Breckenridge AM, Cholerton S, Hart JAD, Park BK, Scott AK (1985) A study of the relationship between the pharmacokinetics and the pharmacodynamics of the 4-hydroxycoumarin anticoagulants warfarin, difenacoum and brodifacoum in the rabbit. Br J Pharmacol 84:81–91Google Scholar
  10. Campbell TW, Ellis CK (2007) Hematology Of Birds. In: Campbell TW, Ellis CK (eds) Avian and exotic hematology and cytology, 3rd edn. Blackwell Publishing, Ames, pp 3–50Google Scholar
  11. Carpenter NA (2000) Anseriform and galliform therapeutics. Vet Clin N Am Exot Anim Pract 3:1–17Google Scholar
  12. Chang RJ, Doherty TM, Goldberg SL (1998) How does warfarin affect the activated coagulation time? A Heart J 136:477–478CrossRefGoogle Scholar
  13. Cheng KM, Bennett DC, Mills AD (2010) The Japanese Quail. In: Hurbrecht R, Kirkwood J (eds) UFAW handbook on the care and management of laboratory animals, 8th edn. Blackwell Science Ltd, London, pp 655–673CrossRefGoogle Scholar
  14. Christensen TL, Lassen P, Elmeros M (2012) High exposure rates of anticoagulant rodenticides in predatory bird species in intensively managed landscapes In Denmark. Arch Environ Contam Toxicol 63(3):437–444CrossRefGoogle Scholar
  15. Coenen TMM, Enninga IC, Cave DA, van der Hoeven JCM (1994) Hematology and serum biochemistry of Japanese quail fed dietary tri-n-butyltin oxide during reproduction. Arch Environ Contam Toxicol 26:227–233CrossRefGoogle Scholar
  16. Cox PR, Smith RH (1990) Rodenticide ecotoxicology: assessing non-target population effects. Funct Ecol 42:315–320CrossRefGoogle Scholar
  17. Doerr JA, Wyatt RD, Hamilton PB (1975) Investigation and standardization of prothrombin times in chickens. Poult Sci 54:969–980CrossRefGoogle Scholar
  18. Doerr JA, Wyatt RD, Hamilton PB (1976) Impairment of coagulation function during aflatoxicosis in young chickens. Toxicol Appl Pharmacol 35:437–446CrossRefGoogle Scholar
  19. Drabkin DL, Austin JH (1935) Spectrophotometric studies: V. A technique for the analysis of undiluted blood and concentrated hemoglobin solutions. J Biol Chem 112:105–115Google Scholar
  20. Duxbury BM, Poller L (2001) State-of-the-art review: the oral anticoagulant Saga: past, present, and future. Clin Appl Thromb/Haemost 7:269–275CrossRefGoogle Scholar
  21. Eason CT, Fagerstone KA, Eisemann JD, Humphrys S, O’Hare JR, Lapidge SJ (2010) A review of existing and potential New World and Australasian vertebrate pesticides with a rationale for linking use patterns to registration requirements. Int J Pest Manage 56(2):109–125CrossRefGoogle Scholar
  22. Eason CT, Murphy EC, Wright GRG, Spurr EB (2002) Assessment of risks of brodifacoum to non-target birds and mammals in New Zealand. Ecotoxicology 11:35–48CrossRefGoogle Scholar
  23. Elliott JE, Hindmarch S, Albert CA, Emery J, Maisonneuve F, Mineau P (2014) Exposure pathways of anticoagulant rodenticides to non-target wildlife. Environ Monit Assess 186:895–906CrossRefGoogle Scholar
  24. Elliott JE, Birmingham AL, Wilson LK, McAdie M, Trudeau S, Mineau P (2008) Fonofos poisons raptors and waterfowl several months after granular application. Environ Toxicol Chem 27(2):452–460CrossRefGoogle Scholar
  25. Elliott JE, Langelier KM, Scheuhammer AM, Sinclair PH, Whitehead PE (1992) Incidence of lead poisoning in Bald Eagles and lead shot in waterfowl gizzards from British Columbia, 1988-91. Canadian Wildlife Service, Progress Notes, Ottawa, ON, No. 200, p 7Google Scholar
  26. Environment Canada (2011) Consultation on Amending the List of Species under the Species at Risk Act Terrestrial Species. Accessed November 2013
  27. Franson JC, Pain DJ (2011) Lead in birds. In: Beyer WN, Meador JP (eds) Environmental contaminants in biota: interpreting tissue concentrations. CRC Press, Boca Raton, pp 563–594CrossRefGoogle Scholar
  28. Friedrichs KR, Harr KE, Freeman KP, Szladovits B, Walton RM, Barnhart KF, Blanco Chavez J (2012) ASVCP reference interval guidelines: determination of De Novo reference intervals in veterinary species and other related topics. Vet Clin Pathol 41(4):441–453CrossRefGoogle Scholar
  29. Gabriel MW, Woods LW, Poppenga R, Sweitzer RA, Thompson C, Matthews SM, Higley JM, Keller SM, Purcell K, Barrett RH, Wengert GM, Sacks BN, Clifford DL (2012) Anticoagulant rodenticides on our public and community lands: spatial distribution of exposure and poisoning of a rare forest carnivore. PLoS ONE 7(7):e40163CrossRefGoogle Scholar
  30. Geffré A, Concordet D, Braun JP, Trumel C (2011) Reference value advisor: a new freeware set of macroinstructions to calculate reference intervals with microsoft excel. Vet Clin Pathol 40(1):107–112CrossRefGoogle Scholar
  31. Godfrey MER (1985) Non-target and secondary poisoning hazards of “second generation” anticoagulants. Acta Zool Fenn 173:209–212Google Scholar
  32. Gray A, Eadsforth CV, Dutton AJ, Vaughan JA (1994) The toxicity of three second-generation rodenticides to barn owls. Pest Sci 42:179–184CrossRefGoogle Scholar
  33. Griminger P (1986) Coagulation. In: Sturkie PD (ed) Avian physiology, 4th edn. Springer, New York, pp 121–125Google Scholar
  34. Hadler MR, Shadbolt RS (1975) Novel 4-hydroxycoumarin anticoagulants active against resistant rats. Nature 253:275–277CrossRefGoogle Scholar
  35. Harr KE (2011) Overview of Avian hemostasis. In: Weiss D, Wardrop J (eds) Schlam’s veterinary hematology, 6th edn. Wiley, HobokenGoogle Scholar
  36. Hill EF, Fleming WJ (1982) Anticholinesterase poisoning of birds: field monitoring and diagnosis of acute poisoning. Environ Toxicol Chem 1(1):27–38CrossRefGoogle Scholar
  37. Hindmarch S (2010) and Configuration on Barn Owl (Tyto Alba) Distribution, Diet And Productivity In The Fraser Valley, British Columbia. M.Sc. Thesis. Department of Biological Sciences, Simon Fraser University, Burnaby, BCGoogle Scholar
  38. Hindmarch S, Elliott JE (2014) A specialist in the city: the diet of barn owls along a rural to urban gradient. Urban Ecosyst. doi: 10.1007/s11252-014-0411-y Google Scholar
  39. Hindmarch S, Krebs EA, Elliott JE, Green DJ (2014a) Urban development influences the breeding success of barn owls in the Fraser Valley, British Columbia, Canada. Condor 116:507-517.CrossRefGoogle Scholar
  40. Hindmarch S, Krebs EA, Elliott JE, Green DJ (2014b) Urban development reduces fledging success of Barn Owls in British Columbia, Canada. The Condor: Ornithological Applications 116(4):507–517CrossRefGoogle Scholar
  41. Howald GR (1997) The Risk of Non-Target Species Poisoning from Brodifacoum Used to Eradicate Rats From Langara Island, British Columbia, Canada. M.Sc. Thesis. Department of Animal Science, University of British Columbia, Vancouver, British ColumbiaGoogle Scholar
  42. James SB, Raphael BL, Cook RA (1998) Brodifacoum toxicity and treatment in a white-winged wood duck (Cairina scutulata). J Zoo Wildl Med 29:324–327Google Scholar
  43. Mann K, Nesheim M, Church W, Haley P, Krishnaswamy S (1990) Surface-dependent reactions of the vitamin K-dependent enzyme complexes. Blood 76:1–16Google Scholar
  44. Massey JG, Valutis L, Marzluff J, Powers LV (1997) The anticoagulant diphacinone’s effect on crow prothrombin time. Proc Annu Conf Assoc Avian Vet, Bedford, pp 97–98Google Scholar
  45. Mendenhall VM, Pank LF (1980) Secondary poisoning of owls by anticoagulant rodenticides. Wildl Soc Bull 8:311–315Google Scholar
  46. Middleton DJ, Watson ADJ (1978) Activated coagulation times of whole blood in normal dogs and dogs with coagulopathies. J Small Anim Pract 19:417–422CrossRefGoogle Scholar
  47. Morrisey JK, Paul-Murphy J, Fialkowski JP, Hart A, Darien BJ (2003) Estimation of prothrombin times of hispaniolan amazon parrots (Amazona ventralis) and umbrella cockatoos (Cacatua alba). J Avian Med Surg 17:72–77CrossRefGoogle Scholar
  48. Mosterd JJ, Thijssen HHW (1991) The Long-Term Effects Of The Rodenticide, Brodifacoum, On Blood Coagulation And Vitamin K Metabolism In Rats. Br J Pharmacol 104:531–535CrossRefGoogle Scholar
  49. Murray M, Tseng F (2008) Diagnosis and treatment of secondary anticoagulant rodenticide toxicosis in a red-tailed hawk (Buteo janaicensis). J Avian Med Surg 22:41–46CrossRefGoogle Scholar
  50. Murray M (2011) Anticoagulant rodenticide exposure and toxicosis in four species of birds of prey presented to a wildlife Clinic In Massachusetts, 2006-2010. J Zoo Wild Med 42(1):88–97CrossRefGoogle Scholar
  51. Newton I, Wyllie I, Freestone P (1990) Rodenticides in British barn owls. Environ Pollut 68:101–117CrossRefGoogle Scholar
  52. PMRA (2010) Proposed risk mitigation measures for eight rodenticides. REV2010-17. Pest Management Regulatory Agency, Health Canada, Ottawa, OntarioGoogle Scholar
  53. Ponczek MB, Gailani D, Doolittle RF (2008) Evolution of the contact phase of vertebrate blood coagulation. J Thromb Haemost 6(11):1876–1883CrossRefGoogle Scholar
  54. Rattner BA, Horak KE, Lazarus RS, Goldade DA, Johnston JJ (2014) Toxicokinetics and coagulopathy threshold of the rodenticide diphacinone in eastern screech-owls (Megascops asio). Environ Toxicol Chem 33(1):74–81CrossRefGoogle Scholar
  55. Rattner BA, Horak KE, Lazarus RS, Eisenreich KM, Metever CU, Volker SF, Campton CM, Eisemann JD, Johnston JJ (2012a) Assessment of toxicity and potential risk of the anticoagulant rodenticide diphacinone using eastern screech owls (Megascops asio). Ecotoxicology 21(3):832–846CrossRefGoogle Scholar
  56. Rattner BA, Horak KE, Warner SE, Day DD, Meteyer CU, Volker SF, Eisemann JD, Johnston JJ (2011) Acute toxicity, histopathology, and coagulopathy in american kestrels (Falco sparverius) following administration of the rodenticide diphacinone. Environ Toxicol Chem 30(5):1213–1222CrossRefGoogle Scholar
  57. Rattner BA, Horak KE, Lazarus RS, Eisenreich KM, Metever CU, Volker SF, Campton CM, Eisemann JD, Johnston JJ (2012b) Assessment of toxicity and potential risk of the anticoagulant rodenticide diphacinone using eastern screech owls (Megascops asio). Ecotoxicology 21(3):832–846CrossRefGoogle Scholar
  58. Savarie PJ, Hayes DJ, Bride RT, Roberts JD (1979) Efficacy and Safety of Diphacinone as a Predacide. In Kenaga EE, ed, Avian And Mammalian Wildlife Toxicology, Special Technical Publication 693 ed, American Society for Testing and Materials, pp 67–79Google Scholar
  59. Shlosberg A, Booth L (2006) Veterinary and clinical treatment of vertebrate pesticide poisoning – a technical review. Landcare Research, Lincoln, New Zealand. Environ Pollut 91(3):279–282Google Scholar
  60. Stone WB, Okoniewski JC, Stedelin JR (1999) Poisoning of wildlife with anticoagulant rodenticides in New York. J Wildlife Dis 35(2):187–193CrossRefGoogle Scholar
  61. Stone WB, Okoniewski JC, Stedelin JR (2003) Anticoagulant rodenticides and raptors: recent findings from New York, 1998–2001. Bull Environ Contam Toxicol 70:34–40CrossRefGoogle Scholar
  62. Stopforth A (1970) A Study of coagulation mechanism in domestic chickens. J Comp Pathol 80:525–533CrossRefGoogle Scholar
  63. Stroud RK (2012) Bruising encounters in veterinary forensics. Vet J 194:278–279CrossRefGoogle Scholar
  64. Tahira N, Dube B, Agrawal GP (1977) Blood coagulation studies in some wild indian birds: effect of different tissue thromboplastins. J Comp Pathol 87:451–457CrossRefGoogle Scholar
  65. Thomas PJ, Mineau P, Shore RF, Champoux L, Martin PA, Wilson LK, Fitzgerald G, Elliott JE (2011) Second generation anticoagulant rodenticides in predatory birds: probabilistic characterisation of toxic liver concentrations and implications for predatory bird populations in Canada. Environ Int 37:914–920CrossRefGoogle Scholar
  66. Tseng LW, Hughes D, Giger U (2001) Evaluation of a point-of-care coagulation analyzer for measurement of prothrombin time, activated partial thromboplastin time, and activated clotting time in dogs. Am J Vet Res 62(9):1455–1460CrossRefGoogle Scholar
  67. US EPA (2004) Potential risks of nine rodenticides to birds and nontarget mammals: a comparative approach. Office of Pesticides Programs, Environmental Fate and Effects Division, Washington, DCGoogle Scholar
  68. US EPA (2008) Risk mitigation decision for ten rodenticides. Office of Pesticides Programs, Environmental Fate and Effects Division, Washington, DCGoogle Scholar
  69. US EPA (2011) Risks Of Non-Compliant Rodenticides To Nontarget Wildlife Background Paper For Science Advisory Panel On Notice Of Intent To Cancel Non-Rmd Compliant Rodenticide Products. Office of Chemical Safety and Pollution PreventionGoogle Scholar
  70. Wadelius M, Pirmohamed M (2007) Pharmacogenetics of warfarin: current status and future challenges. Pharmacogenomics J 7:99–111CrossRefGoogle Scholar
  71. Walker LA, Turk A, Long SM, Wienburg CL, Best J, Shore RF (2008) Second generation anticoagulant rodenticides in tawny owls (Strix aluco) from Great Britain. Sci Tot Environ 392:93–98CrossRefGoogle Scholar
  72. Watanabe KP, Saengtienchai A, Tanaka KD, Ikenaka Y, Ishizuka M (2010) Comparison of warfarin sensitivity between rat and bird species. Comp Biochem Physiol Part C: Toxicol & Pharmacol: 152(1):114–119Google Scholar
  73. Watt BE, Proudfoot AT, Bradberry SM, Vale JA (2005) Anticoagulant rodenticides. Toxicol Rev 24(4):259–269CrossRefGoogle Scholar
  74. Weiss D, Wardrop J (eds) (2011) Schlam’s veterinary hematology, 6th edn. Wiley, HobokenGoogle Scholar
  75. WHO (1995) Brodifacoum Health and Safety Guide. 93. World Health Organization, GenevaGoogle Scholar

Copyright information

© Her Majesty the Queen in Rights of Canada 2015

Authors and Affiliations

  • Kirstin H. Webster
    • 1
  • Kendal E. Harr
    • 2
  • Darin C. Bennett
    • 3
  • Tony D. Williams
    • 1
  • Kimberly M. Cheng
    • 3
  • France Maisonneuve
    • 4
  • John E. Elliott
    • 1
    • 3
    • 5
  1. 1.Department of Biological SciencesSimon Fraser UniversityBurnabyUSA
  2. 2.URIKA LLCMukilteoUSA
  3. 3.Avian Research CentreFaculty of Land and Food Systems, University of British ColumbiaVancouverUSA
  4. 4.Science & Technology BranchNational Wildlife Research Centre, Environment CanadaOttawaCanada
  5. 5.Science & Technology BranchPacific Wildlife Research Centre, Environment CanadaDeltaCanada

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