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

2009 ◽  
Vol 36 (8) ◽  
pp. 709 ◽  
Author(s):  
Kate E. Littin ◽  
Neville G. Gregory ◽  
Andrea T. Airey ◽  
Charles T. Eason ◽  
David J. Mellor
Keyword(s):  
New Zealand ◽  
Animal Welfare ◽  
Lethal Dose ◽  
Total Loss ◽  
Sublethal Dose ◽  
Loss Of Consciousness ◽  
Trichosurus Vulpecula ◽  
Welfare Impacts ◽  
Behavioural Changes ◽  
H 26

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.

A systematic approach to evaluating and ranking the relative animal welfare impacts of wildlife control methods: poisons used for lethal control of brushtail possums (Trichosurus vulpecula) in New Zealand

2016 ◽  
Vol 43 (7) ◽  
pp. 553 ◽  
Author(s):  
N. J. Beausoleil ◽  
P. Fisher ◽  
K. E. Littin ◽  
B. Warburton ◽  
D. J. Mellor ◽  
...  
Keyword(s):  
New Zealand ◽  
Animal Welfare ◽  
Policy Development ◽  
Management Decision ◽  
Pest Species ◽  
Control Methods ◽  
Trichosurus Vulpecula ◽  
Welfare Impacts ◽  
Wildlife Control ◽  
Management Decision Making

Context Control of unwanted wildlife (‘pest’ animals) is undertaken for conservation and economic reasons, and when such animals are considered a nuisance. Such control should be undertaken using approaches that minimise, as far as possible, detrimental impacts on the welfare of the animals. Using a scientific framework based on the Five Domains model, the relative welfare impacts of pest control methods can be compared across methods and pest species. Aims We demonstrate the application of a modified version of this framework to evaluate the relative impacts of seven Vertebrate Toxic Agents (VTAs) used to control brushtail possums (Trichosurus vulpecula) in New Zealand. The evaluation is used to produce a ranking of the seven VTAs based on their relative impacts on possum welfare. Methods Scientific literature describing mode of toxic action, specific effects in possums or other animals and reports from human poisonings was collated as reference material for a panel of six experts. The panel produced a median welfare impact score (‘none’ to ‘extreme’) for each of the Five Domains. The ‘Overall Grade’ (1 to 8) reflected the intensity and duration of all impacts of a VTA on possums. Key results All VTAs evaluated have at least moderate impacts on possum welfare, lasting for at least minutes. Cyanide was assessed as having the lowest welfare impacts (median grade 4), and cholecalciferol and the anticoagulants the highest impacts (7.5 to 8). Zinc phosphide was assigned an intermediate grade (6) with high confidence. While the overall impacts of sodium fluoroacetate (1080) and phosphorus were also assessed as intermediate (6), the panel’s confidence in these scores was low. Conclusions From an animal welfare perspective, anticoagulant poisons and cholecalciferol should be the least preferred options for controlling possums in New Zealand, as VTAs with less severe welfare impacts are available. Implications The results of such assessments allow animal welfare impacts to be integrated with other factors in wildlife management decision-making and policy development, and are thus useful for managers, researchers, regulators and operators. Evaluation of welfare impacts aligns with the goals and mandates of ethical wildlife control and may also be valuable in wider wildlife research and management activities.

scholarly journals Implications of prefeeding for the development of bait aversions in brushtail possums (Trichosurus vulpecula)

1998 ◽  
Vol 25 (2) ◽  
pp. 133 ◽  
Author(s):  
Zane N. Moss ◽  
Cheryl E. O'Connor ◽  
Graham J. Hickling
Keyword(s):  
New Zealand ◽  
Pest Control ◽  
Subsequent Development ◽  
Sublethal Dose ◽  
Trichosurus Vulpecula ◽  
Management Procedure

Development of aversions, or learned ‘bait-shyness’, in frequently poisoned possum (Trichosurus vulpecula) populations is becoming increasingly detrimental to the efficacy of pest-control operations in New Zealand. This experiment aimed to identify the effects of prefeeding, a common management procedure, on the subsequent development of aversions in possums. Wild possums (n = 96) were captured and acclimatised, then allocated to one of three treatments groups that for seven days received either (i) no prefeed, (ii) plain RS5 cereal baits, or (iii) green-dyed and cinnamon-lured RS5 cereal baits. The possums were then offered a standard green-dyed and cinnamon-lured RS5 bait that contained a sublethal dose (0.4 mg kg-1) of the toxin sodium monofluoroacetate (1080). The possums were tested for development of an aversion towards a toxic RS5 1080 bait, a prefeed bait, and a prefeed bait containing an alternative toxin, brodifacoum. Most (96%) of the non-prefed possums became averse to the 1080 bait after two exposures, compared with only 55% and 9% of the two prefed groups. Similarly, 90% and 92% of the non-prefed possums were averse to prefeed and brodifacoum baits, respectively, compared with 8% and 14% of the prefed possums. This suggests that pest managers can reduce the risk of ‘bait shyness’ by prefeeding. A further advantage of prefeeding is that if poison shyness develops, use of an alternative toxin such as brodifacoum in the original bait base may still be successful.

Optimising bait size and 1080 concentration (sodium monofluoroacetate) for the control of brushtail possums Trichosurus vulpecula)

1999 ◽  
Vol 26 (1) ◽  
pp. 53 ◽  
Author(s):  
C. M. Frampton ◽  
B. Warburton ◽  
R. Henderson ◽  
D. R. Morgan
Keyword(s):  
New Zealand ◽  
Weight Distribution ◽  
Lethal Dose ◽  
Distribution Data ◽  
Trichosurus Vulpecula ◽  
Toxic Concentration ◽  
The Mean ◽  
Quantitative Assessments

A method is presented for quantitatively assessing the likely effectiveness of specific bait size and 1080 concentration for controlling brushtail possums with a known weight distribution. Data from aerial 1080 operations for the control of brushtail possums in New Zealand show that estimates of the bait size and toxic concentration required derived from the mean parameters [pest weight, bait size, and lethal dose (LD 95)] will not be accurate. This inaccuracy is most likely to lead to an underestimate of the amount of toxin presented to each animal, so that many operations currently run the risk of sub-lethally dosing possums and thereby possibly inducing some degree of poison shyness. On the basis of more accurate quantitative assessments of bait effectiveness we recommend that the 1080 concentration be increased to 0.15% and that baits less than 5 g be excluded to ensure that when mean possum weights are less than 3 kg more than 95% of possums are lethally dosed by a single bait.

scholarly journals Efficacy and Animal Welfare Impacts of Novel Capture Methods for Two Species of Invasive Wild Mammals in New Zealand

Animals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 44
Author(s):  
A. David M. Latham ◽  
Ben Davidson ◽  
Bruce Warburton ◽  
Ivor Yockney ◽  
Jordan O. Hampton
Keyword(s):  
New Zealand ◽  
Animal Welfare ◽  
Cervus Elaphus ◽  
Red Deer ◽  
Field Methods ◽  
Wild Mammals ◽  
Welfare Impacts ◽  
Mortality Cost ◽  
Induction Times ◽  
Capture Techniques

All capture methods impose animal welfare impacts, but these impacts are rarely quantified or reported. We present data from two wildlife capture studies that trialled new methods for capturing Bennett’s wallabies (Notamacropus rufogriseus) and red deer (Cervus elaphus) in New Zealand. We used helicopter net-gunning for both species, and compared this method with ground-based netting for wallabies and helicopter darting for red deer, using, for the first time in New Zealand, the fast-acting opioid thiafentanil. Efficacy and animal welfare parameters quantified were duration of handling and recovery, and frequency of adverse events, including escape, injury, and mortality. Cost-effectiveness was quantified for each method. Capture mortalities occurred for all methods for both species. For red deer, chemical immobilisation led to fewer traumatic injuries and fewer mortalities, while for wallabies, net-gunning led to fewer mortalities. Net-gunning was an efficient capture method for deer in open habitat, but led to the escape of 54% of wallabies and one wallaby mortality (4%). Ground-based netting resulted in the mortality of 17% of wallabies at the time of capture, and the capture of non-target species. The cost per captured wallaby was 40% more expensive for net-gunning (NZ$1045) than for ground-based netting (NZ$745), but, once corrected for mortalities at the time of capture and suitability of individuals for GPS-collar deployment, this was reduced to 29% and 12% more expensive, respectively. Net-gunning for red deer resulted in the escape of 13% of animals and mortality of 10% of animals at the time of capture. Helicopter-based darting for red deer using thiafentanil (c. 0.03–0.06 mg/kg) had high capture efficacy (zero escapes), rapid induction times (mean of 3 min), and a low mortality rate at 14 days post-capture (3%), but it was more expensive per deer captured and collared than aerial netting (NZ$2677 and NZ$2234, respectively). We recommend reporting of adverse event data for all wildlife capture techniques to permit continual refinement of field methods.

Induced 1080 Bait-Shyness in Captive Brushtail Possums and Implications for Management.

1996 ◽  
Vol 23 (2) ◽  
pp. 207 ◽  
Author(s):  
DR Morgan ◽  
G Morriss ◽  
GJ Hickling
Keyword(s):  
New Zealand ◽  
Sublethal Dose ◽  
Trichosurus Vulpecula

The probable cause of possums (Trichosurus vulpecula) becoming 'shy' towards 1080 [sodium fluoroacetate] bait, a growing problem in the control of this pest, was determined. Possums captured from North Canterbury, New Zealand, (n = 131) were offered sublethal baits (1 or 2.5 g) followed by lethal (6 g) baits 2 days later. Most possums became bait shy and the proportion becoming shy appeared to be related to the size of the initial sublethal dose. Most of a group of survivors retested after 3 months with toxic pellets were still shy. Shyness was not overcome by changing to a different mask (orange flavour, as opposed to cinnamon flavour) or toxin (brodifacoum), but changing to both a different bait base (carrot) and mask (orange) resulted in most shy possums eating a lethal quantity of bait. Possums therefore appeared to learn to recognise the bait base as the cue for avoiding poisoning. More shy possums than naive possums rejected non-dyed, non-masked, non-toxic pellets, confirming that shy possums recognised the bait base. Green dye appears to act as a secondary cue for avoiding pellets as a higher percentage of 'shy' possums than naive possums rejected dyed baits.

Effect of prefeeding on foraging patterns of brushtail possums (Trichosurus vulpecula) about prefeed transects

2009 ◽  
Vol 36 (8) ◽  
pp. 659 ◽  
Author(s):  
B. Warburton ◽  
R. Clayton ◽  
G. Nugent ◽  
G. Graham ◽  
G. Forrester
Keyword(s):  
New Zealand ◽  
Agricultural Production ◽  
Lethal Dose ◽  
Trichosurus Vulpecula ◽  
Gradual Decline ◽  
Foraging Patterns ◽  
Major Pest ◽  
Number Of Visits ◽  
The Wire ◽  
Free Feeding

Context. Brushtail possums (Trichosurus vulpecula) are a major pest of native biodiversity and agricultural production in New Zealand. To maximise the effectiveness of control operations, prefeeding (free-feeding) of non-toxic bait before poison is often used, but the mechanisms by which it does so, remain unclear. One possibility is that prefeeding changes foraging patterns and space use in ways that increase the likelihood of possums finding and eating a lethal dose of poison bait. Aim. To determine whether prefeeding along transects increases possum activity on the transect, and if so, how long the effect lasts. Methods. We monitored the time that radio-collared possums spent within a few metres of 350 m of aerial wire laid along a transect. Key results. Initially, possums spent only 2.6 min per night in the vicinity of the wire, but after 20 kg of bait per kilometre were placed along the wire, that time increased 20-fold on the first night and remained high for the next four nights (by which time all of the bait had been consumed). After that there was a gradual decline in time spent near the wire over a further 18 days. The increased amount of time spent near the wire was the product of both an increase in the number of visits and the duration of those visits. Conclusions. We conclude that sowing prefeed in concentrated strips is likely to greatly increase the probability of possums rapidly encountering toxic bait sown along the same strips, especially where the toxin can be sown immediately after all of the prefeed has been eaten. Implications. Possum control operations can now be designed to apply much smaller quantities of toxic bait that will potentially reduce concerns about 1080 poisoning because of a move away from broadcast sowing operations that are intuitively disliked by many, to much more localised baiting regimes.

scholarly journals Age and Infectious Dose Significantly Affect Disease Progression after RHDV2 Infection in Naïve Domestic Rabbits

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1184
Author(s):  
Robyn N. Hall ◽  
Tegan King ◽  
Tiffany O’Connor ◽  
Andrew J. Read ◽  
Jane Arrow ◽  
...  
Keyword(s):  
New Zealand ◽  
Disease Progression ◽  
Case Fatality Rate ◽  
Low Dose ◽  
Case Fatality ◽  
Wild Rabbit ◽  
Fatality Rate ◽  
Infectious Dose ◽  
Welfare Impacts ◽  
Rabbit Haemorrhagic Disease

Rabbit haemorrhagic disease virus 2 (RHDV2 or GI.2, referring to any virus with lagovirus GI.2 structural genes) is a recently emerged calicivirus that causes generalised hepatic necrosis and disseminated intravascular coagulation leading to death in susceptible lagomorphs (rabbits and hares). Previous studies investigating the virulence of RHDV2 have reported conflicting results, with case fatality rates ranging from 0% to 100% even within a single study. Lagoviruses are of particular importance in Australia and New Zealand where they are used as biocontrol agents to manage wild rabbit populations, which threaten over 300 native species and result in economic impacts in excess of $200 million AUD annually to Australian agricultural industries. It is critically important that any pest control method is both highly effective (i.e., virulent, in the context of viral biocontrols) and has minimal animal welfare impacts. To determine whether RHDV2 might be a suitable candidate biocontrol agent, we investigated the virulence and disease progression of a naturally occurring Australian recombinant RHDV2 in both 5-week-old and 11-week-old New Zealand White laboratory rabbits after either high or low dose oral infection. Objective measures of disease progression were recorded through continuous body temperature monitoring collars, continuous activity monitors, and twice daily observations. We observed a 100% case fatality rate in both infected kittens and adult rabbits after either high dose or low dose infection. Clinical signs of disease, such as pyrexia, weight loss, and reduced activity, were evident in the late stages of infection. Clinical disease, i.e., welfare impacts, were limited to the period after the onset of pyrexia, lasting on average 12 h and increasing in severity as disease progressed. These findings confirm the high virulence of this RHDV2 variant in naïve rabbits. While age and infectious dose significantly affected disease progression, the case fatality rate was consistently 100% under all conditions tested.

Medical Record Documentation of Seizures

1992 ◽  
Vol 13 (2) ◽  
pp. 76-77
Keyword(s):  
Medical Record ◽  
Chief Complaint ◽  
Total Loss ◽  
Loss Of Consciousness ◽  
Pertinent Data ◽  
Sample Record ◽  
Medical Record Documentation

This sample record is meant to demonstrate comprehensive recording of pertinent data. Actual records will vary in format; many will be written in a more abbreviated style. Name: Sharon DiStefano1 Date of birth: December 8, 19832 Drug allergies: None; cramps from erythromycin3 Immunizations: Fully immunized4 Thursday, February 6, 1992 Telephone Teacher called parents — Sharon "suddenly gets a blank look" for brief periods. Has done this several times. Parents will get further information from teacher, watch carefully over weekend, bring in for visit next week. Tuesday, February 11, 1992 CHIEF COMPLAINT: "We think she's having spells." PRESENT ILLNESS: (See letter from teacher). He has noted over the last week, on 5 or 6 occasions, that Sharon will develop "blank stare" suddenly. When talked to, will not respond at first but will after several repetitions. Once did this in the middle of talking; paused noticeably for a number of seconds, then resumed talking. Eyes always stay open; blinking noted; no total loss of consciousness. No jerking, twitching, slumping, drooling, incontinence. Seems normal afterwards; not aware of any lapse. Over the weekend parents saw similar spells: three times at meals, twice when watching television, once after she had been running around backyard and had just sat down. "Like a shade was drawn behind her eyes."

scholarly journals Ecology of a brushtail possum (Trichosurus vulpecula) population at Castlepoint in the Wairarapa, New Zealand

2019 ◽  
Vol 43 (2) ◽  
Author(s):  
Ron Jackson ◽  
D.U. Pfeiffe ◽  
T Porphyre ◽  
C Sauter-Louis ◽  
L.A.L. Corner ◽  
...  
Keyword(s):  
New Zealand ◽  
Brushtail Possum ◽  
Trichosurus Vulpecula
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