Application for approval to manufacture ESN containing sodium nitrite and a bait containing sodium nitrite to be used as a Vertebrate Toxic Agent for the control of brushtail possums ( Trichosurus vulpecula ) and feral pigs ( Sus scrofa )
Application context • It is clearly stated in our EPA application that in our opinion the majority of use for this bait will be for possum control • Sodium nitrite an additional tool for possum and feral pig control not an outright replacement for current methods • Sodium nitrite and PAPP have been developed as new toxins, both have the same mode of action and the same antidote • PAPP registered for stoats and feral cats but not toxic to possums; hence the complementary development of a sodium nitrite bait
Speakers • Lee Shapiro – Connovation Ltd • Dr Alastair Fairweather – Department of Conservation • Nick Hancox – Animal Health Board • Jack Craw – Auckland Council
Connovation Ltd Background • Manufacturer of pest control products for 18 years • Commercial products for controlling vertebrate pest species: possums, rodents, mustelids (stoats, ferrets and weasels) and wallabies • A focus on low residue and humane toxins • Registration of PAPP - a new toxin - for stoat and feral cat control 2011
Overview Possums and feral pigs Benefits • Non persistent in environment Impacts • • Sub-lethal doses rapidly eliminated Native biodiversity • • Non persistent in poisoned animals Possums known TB vector • • Very low risk secondary poisoning Pigs implicated transmission of PTA • Effective antidote • Relatively humane Limitations current control • Possums -brodifacoum, 1080, cyanide • Lack antidote or complex treatment Sodium nitrite • • Anticoagulant residues NaNO 2 • • Anticoagulants low welfare ranking Common food preservative • • Feral pigs - Hunting Cereal paste 100g/kg SN • • No registered pig toxin Reduces oxygen transport
Impacts of possums and feral pigs • Possums and feral pigs Impact and cause damage to: Native biodiversity including rare native plants, frogs, lizards, invertebrates, birds and their eggs Pasture, crops and young plantation trees Native forest regeneration • Possums Known vector for bovine tuberculosis ( Mycobacterium bovis ) • Feral pigs Pigs implicated in spreading kauri dieback disease (Phytophthora taxon agathis)
Limitations of current control • Possums Commonly controlled with anticoagulants, 1080, cyanide and trapping Lack an antidote or complex treatment required for accidental poisoning Anticoagulant residues can accumulate in sub-lethally poisoned animals and also cause secondary poisoning Anticoagulants have highest relative impact on welfare of all VTAs registered for possum control Withholding periods exclude hunters from blocks indefinitely - 3 years recommended for 2 nd generation anticoagulants Restrictions on use e.g. brodifacoum not allowed on DoC estate
Limitations of current control • Feral pigs Controlled by hunting with and without dogs and from a helicopter as well as trapping Currently no registered toxin for feral pig control in NZ No current method for rapid knock down in the case of a disease outbreak e.g. foot and mouth Certain areas where hunter access is not permitted or possible for pig control I. Public spaces where firearms or hunting not permitted II. Areas where risks to certain species e.g. Kiwi from pig dogs III. Areas with sensitive terrain e.g. Sensitive geothermal features IV. Private farms/properties that do not want hunters
The Application • To manufacture ESN containing sodium nitrite at 950 g/kg and a bait containing sodium nitrite at 100 g/kg to be used as a Vertebrate Toxic Agent • Shown to be effective at controlling possums and feral pigs • Baiting will be in bait stations • Baits will be coloured green or blue • Permission needed to use on DoC land
The Application • Sodium nitrite paste bait will provide a safe, low residue and humane toxin for possum and feral pig control • Will provide market choice with another control tool • Response readiness as no registered feral pig toxin • Control of possums using sodium nitrite baits will increase access to certain areas for hunting
Sodium nitrite (NaNO 2 ) • Common food additive - preservative in bacon, ham and salami • Toxic in higher doses • Reduces the ability of red blood cells to transport oxygen • Added to a cereal paste bait for possum and feral pig control • Time to death approx. 1 -2 hours for possums and feral pigs
Sodium nitrite • Not persistent in the environment • Sub-lethal doses quickly eliminated • Not persistent in poisoned animals • Very low risk of secondary poisoning • Effective antidote exists • Relatively humane
Not persistent in the environment
Sub-lethal doses quickly eliminated Not persistent in poisoned animals Very low risk of secondary poisoning Group Compound Half-life values Likely persistence of residues after sub-lethal exposure 1 Cyanide + 12-24 hours Sodium nitrite <60 minutes <12 hours 1080 <11 hours 7 days 2 Pindone 2.1 days 4 weeks 3 Cholecalciferol 10-68 days 3 months 4 Brodifacoum 130-350 days 24 months or longer + = No published value but likely to be <12 h based on published information on sodium nitrite Table adapted from Eason et al 2008 Proceedings of 23 rd Vertebrate Pest Conference
Effective antidote exists • Veterinarians are familiar with nitrite or nitrate poisoning in grazing ruminants • Active growth of plants after rain following dry or drought conditions can lead to nitrate or nitrite poisoning • Symptoms will include cyanosis, ataxia, unconsciousness and death in untreated animals. • Animals are treated with an injection of methylene blue and recover rapidly
Relatively humane • Trials undertaken to determine the efficacy and welfare of pigs poisoned with sodium nitrite paste bait • Poisoned pigs observed by Dr Cristin Dwyer (BVSc) of Selwyn Rakaia Vet Services “ After ingesting sodium nitrite baits pigs became pale and ataxic” (Lacking motor co -ordination) “ In my opinion the sodium nitrite caused a rapid death with little distress signs evident from the pigs”
Group Compound Symptoms Mean Mean time Relative duration to death degree symptoms of suffering Un-coordination, Mild or moderate Cyanide 6.5 min 17.9 min Low 1 hyperpnoea, Loss of response to handling (indicator of unconsciousness) Convulsions Sodium nitrite Pale nose extremities, vomiting, blue 1 hour 1.5 hours Low 2 tongues, lethargy, ataxia, slight tremors collapse and death. Changed appearance , Retching, Vomiting 1080 9.5 hours 11.5 hours Intermediate 3 Unsteady head movements & walking Minor tremors or spasms , Prolonged lying, prostrate (>2 hours) Cholecalciferol Reduced activity, Rapid breathing, Reduced 4 7 days 9 days High feeding, weight loss, Prostration Mineralisation in organs , Lung pathology Unconsciousness (just prior to death) Changed appearance, Reduced feeding Brodifacoum 7 days 21 days High 5 Diarrhoea, minor; abnormal breathing, shivering, tremors spasms, un coordination Haemorrhages, Prolonged lying, Loss of response to handling & palpebral reflex Information extracted from Gregory et al (1998), O’Connor et al . (2003 and2007), and Littin et al (2000, 2002, 2009)
Support for the application • The Department of Conservation • The Animal Health Board • Auckland Council • Regional Council support: Northland, Environment Southland, Hawkes Bay, Tasman, Greater Wellington • Community Landcare groups: Whangarei Heads Landcare Forum and Whareora Landcare Group
Support from Landcare Groups • “There is a great need for effective pest control tools to protect biodiversity, primary production, disease management and the economy .” • “Sodium nitrite is a leap forward in the development of acceptable pesticides .” • “Feral pigs an indirect but major cause of adult kiwi deaths through pig hunting dogs. Use of sodium nitrite will allow Northland communities to remove feral pigs from areas with significant kiwi populations and avoid deaths of this nature .”
Species 1080 Cyanide Cholecalciferol Brodifacoum Pindone Phosphorus Zinc PAPP Sodium Phosphide nitrite 6 8 8 7.5 6 6 Possum 4 Rodents 6 7.5 NDD Stoat 6.5 (NT) NDD/NT 5.5 Ferret 6.5 (NT) 7.5 (NT) NDD/NT Feral cat 6.5 7.5 (NT) 5.5 Rabbit 6 8 NDD Pig 6.5 (NT) 7 5.5 Deer NDD/NT Wallaby 5.5 (NT) NDD • Table taken from ‘How humane are our pest control tools’ MAFBNZ 2010 • Numerical scores from 1 – 8 assigned as a combination of welfare impact scores and the duration of the welfare impact(s) • The higher the score the higher the overall welfare impact
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