Cholecalciferol-induced bait shyness in possums (Trichosurus vulpecula)

Morgan, David R.; Milne, L.

doi:10.1080/09670870110096592

Cited by 13 publications

(6 citation statements)

References 11 publications

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“…Comparison of these results with those of other poisons shows that 1080 is the second fastest-acting poison available for possum control, with an accordingly short duration of sickness; cyanide is the fastest, causing unconsciousness after 6 min and death after 14 min (Gregory et al 1998), phosphorus paste causes a period of illness of 18 h and death after 25 h (O'Connor et al 2007), cholecalciferol causes death iñ 6 days (Morgan and Milne 2002), and brodifacoum a duration of sickness of about 7 days, with death at~21 days (Littin et al 2002). The degree of suffering caused by 1080 in possums could also be considered to be intermediate.…”

Section: Relative Humaneness Of 1080mentioning

confidence: 97%

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

et al. 2009

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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 AE 1 h 55 min (mean AE s.e.m.). Half had abnormal appearances and postures 1 h 50 min AE 9 min after consuming baits. Seven showed retching, and three vomited, over 27 AE 12 min from 2 h 53 min AE 13 min. Lack of coordination began 3 h 37 min AE 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.

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Section: Relative Humaneness Of 1080mentioning

confidence: 97%

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

et al. 2009

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“…We also assessed the persistence of bait-shyness to 2 toxicants (cyanide and 1080), and examined ways of overcoming shyness based on the use of alternative bait types and toxicants (i.e., "bait-switching"). The main components of this research have been published in detail elsewhere (Morgan et al 1996Morgan and Ross 2001;Morgan and Milne 2002). In this paper we summarize and synthesize this work, focussing in particular on the differences between the 4 toxicants, and the opportunities those differences provide for overcoming the problem.…”

Section: Introductionmentioning

confidence: 97%

Learned bait-shyness by possums (Trichosurus vulpecula) towards baits containing cyanide, 1080, cholecalciferol, or brodifacoum

Morgan¹,

Milne²,

O'Connor³

2002

vertebrate_pest_conference

Self Cite

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Around NZ$76 million per annum is presently spent on controlling and researching the introduced brushtail possum in New Zealand. The national control effort is likely to be further increased over the next decade in an attempt to eradicate bovine tuberculosis and to arrest the degradation of key conservation areas. There is a risk that repeated control operations using toxic baits could result in widespread development of learned "bait-shyness," behavior that develops when sublethally poisoned animals are able to link the experience of an illness with the memory of the bait eaten. Four studies are reviewed that aimed to determine the likelihood of possums becoming shy after sublethal doses imparted by different types of toxic bait, and to find solutions to the problem. Captive possums were presented with baits containing sublethal doses of the 4 vertebrate pesticides commonly used. Following a recovery period, possums were presented with lethal baits and their response compared with that of naive possums. Between 15% and 90% of possums previously dosed with sublethal doses of cyanide, 1080, or cholecalciferol developed baitshyness, the proportion being dose and toxicant dependent. Although cholecalciferol induces toxicosis more slowly (i.e., >24 h) than cyanide (5 min) and 1080 (1 h), possums were nevertheless able to associate the effects of this toxicant with consumption of the bait in which it was delivered and avoid eating further baits. However, brodifacoum acts very slowly (1-4 weeks), and possums did not become shy towards baits containing this toxicant after first eating sublethal baits. Shyness induced by either 1080 or cyanide persisted for at least 12 and 24 months respectively, thus jeopardizing the effectiveness of "maintenance" control operations, which can be required every 12 months or less. The persistence of bait-shyness to cholecalciferol remains untested. Use of alternative baits (bait-switching) proved an effective solution for eliminating cyanide-and 1080-induced bait-shyness. Baits containing brodifacoum can also be used very effectively to "mop up" bait-shy populations, but care must be taken to minimize environmental contamination by this persistent compound.

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“…Bait shyness has been observed in ship rats fed zinc phosphide,6 in Norway rats ( Rattus norvegicus Berk.) fed cholecalciferol1, 7 or calciferol8 and in possums offered a lethal dose of cholecalciferol 21–30 days after presentation of sublethal doses (LD 15 and LD 40 ) 9. Not all species, however, show signs of bait or poison shyness, and may in fact exhibit bait preference.…”

Section: Introductionmentioning

confidence: 99%

Determination of penciclovir in human plasma by liquid chromatography–electrospray ionization tandem mass spectrometry: application to a clinical pharmacokinetic study

Kanneti

Dasandi²,

Paramar³

et al. 2011

Biomedical Chromatography

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A rapid, specific and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the determination of penciclovir in human plasma. The method involved simple, one-step SPE procedure coupled with a C(18) , 75 × 4.mm, 3 µm column with a flow-rate of 0.5 mL/min, and acyclovir was used as the internal standard. The Quattro Micro mass spectrometry was operated under the multiple reaction-monitoring mode using the electrospray ionization technique. Using 250 µL plasma, the methods were validated over the concentration range 52.555-6626.181 ng/mL, with a lower limit of quantification of 52.55 ng/mL. The intra- and inter-day precision and accuracy values were found to be within the assay variability limits as per the FDA guidelines. The developed assay method was applied to a clinical pharmacokinetic study in human volunteers.

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Cholecalciferol-induced bait shyness in possums (Trichosurus vulpecula)

Cited by 13 publications

References 11 publications

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

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

Learned bait-shyness by possums (Trichosurus vulpecula) towards baits containing cyanide, 1080, cholecalciferol, or brodifacoum

Determination of penciclovir in human plasma by liquid chromatography–electrospray ionization tandem mass spectrometry: application to a clinical pharmacokinetic study

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