Mass Depopulation Flashcards
describe depopulation
- NOT routine, euthanasia, or human slaughter
- IS: rapid destruction of a population of animals in response to urgent circumstances with as much consideration given to the welfare of the animals as practicable
- for emergency situations, is complicated and sensitive, high risk, and must still be as human as possible and maintain high ethical standards
when and why is depopulation considered?
- regulatory diseases
- non-regulatory but highly pathogenic diseases
- emerging disease
- zoonotic diseases
- intoxications and adulterations
- radiologic exposure
- natural disaster
- loss of market access
describe depopulation scenarios by species
- regulatory/highly pathogenic/zoonotic:
-cattle: FMD, TB, brucellosis, cattle fever tick
-swine: ASF, CSF, FMD, influenza
-poultry: HPAI, vvNDV - natural disaster:
-cattle and swine: traumatic injury due to smoke, chemical exposure, no access to care/feeding
-poultry: ice storm, tornado, hurricane, flood - agroterrorism
-cattle: anthrax, FMD
-swine: FMD
-poultry: sabotage (VSD) - toxicity:
-cattle: pesticide/mycotoxin/heavy metal or mammalian protein ingestion, ELDU
-swine: dioxin, melamine exposure
-poultry: coccidiostat or mineral overdose
describe the balanced decision making of mass depopulation
- rapid emergency response: animal welfare must be balanced against risk to humans, other populations of animals, or the environment
- veterinarians positioned as authority on animal welfare:
-expected to maintain social contract
-may also be looked to for economic valuation of animal life
-may be expected to lead response/incident command
-often looked to for help ensuring both biosecurity and wellbeing of other responders
describe the depopulation decision tree
- do I have full info needed?
- do I have full info for each step of the entire process to create the best plan?
-pre-planning = critical
-pre-depopulation animal handling
-most appropriate techniques: speed, efficacy, animal behavior/state, environment
-carcass removal and disposal: speed, environmental concerns, public health concerns
describe evaluation of methods of depopulation
- when possible, humane methods (including handling of animals) and agents are designed to minimize anxiety, pain, and distress to bring about rapid loss of consciousness and complete loss of brain function in animals
-vaires by species - evaluated in context of the specific emergency, both severity and urgency
- preferred methods:
-highest priority
-may mirror AVMA guidelines for euthanasia or humane slaughter when feasible - permitted methods:
-in constrained circumstances
-only when preferred methods are not reasonably feasible - not recommended methods:
-last resort
-only when risk of no action would result in greater animal suffering - ALL methods require monitoring and must achieve 100% mortality
describe methods to produce unconsciousness
- humaneness: goal is always to minimize anxiety, pain, and distress BEFORE loss of consciousness
2 depopulation methods produce unconsciousness through 4 methods:
-physical disruption: PCB, gunshot, cervical dislocation, decapitation, blunt force trauma
-hypoxia: controlled low atmospheric pressure, N2, Ar, exsanguination
-direct depression of neurons necessary for life: CO2
-epileptiform brain activity: electric stunning
- sympathetic nervous system and HPA in both physiological and psychological stress, not necessarily associated with consciousness and higher order CNS processing
-used as markers of stress though - evaluated via LORR (LOP): loss of memory formation and awareness lost early relative to loss of reflex muscle activity
- EEG methods do not provide definitive timing of loss of consciousness
describe depopulation methods for cattle and swine
preferred:
-cattle: gunshot, penetrative captive bolt (PCB), IV admin barbiturate, humane slaughter
-swine: gunshot, PCB, electrocution, manual blunt force trauma (very small animals only), inhaled gas (CO2, CO), anesthetic overdose, humane slaughter
permitted (constrained):
-cattle: PCB with sedation, electrocution, compounded/non pharma grade or expired injectable anesthetics/euthanasia agents
-swine: VSD plus, sodium nitrite
not recommended:
-cattle: oral toxins
-swine: N/A
describe depopulation methods for floor-reared poultry
preferred:
-water-based foam
-whole/partial house or containerized gassing
-cervical dislocation
-mech assisted cervical dislocation
-captive bolt
permitted:
-VSD plus
-gunshot
-controlled demolition
-exsanguination
-decapitaiton
not recommended: VSD
describe depopulation methods for cage housed poultry
preferred
-whole/partial house or containerized gassing
permitted:
-compressed air foam
-cervical or mech assisted cervical dislocation
-captive bolt
-VSD plus
-decapitation
not recommended:
-water-based foam
-gunshot
-VSD
describe depopulation methods for free-ranging poultry
preferred:
-containerized gassing
-cervical or mesh assisted cervical dislocation
-captive bolt
permitted:
-water-based foam
-partial house gassing
-VSD plus
-gunshot
-controlled demolition
-exsanguination
-decapitation
not recommended:
-VSD
-whole house gassing
describe the human welfare aspect of depopulation
- considerations for both human and animal safety and welfare must be made congruently in crisis situations
- emergency planning is critical to preventing loss of life, injury, and psychological stress during natural disasters
- decision to depopulate is a shared responsibility, not solely on vet
- be mindful of emotional and economic cost to producers, veterinarians, responders, and society at large
- communication to public at large should be transparent and sensitive
-include targeted education (role is often assigned to veterinarians) - proper training and education of vets and responders
-ongoing disaster preparedness
-adequate equipment and resources - relief and recovery:
-staffing
-overtime pay, recognition
-leave allowances
-stress counseling: caring-killing paradox
describe environmental considerations of depopulation
- plans must be informed by disposal options
-carcass removal and disposal is often the rate limiting factor
-goals: efficient, safe, fast
-multi-party cooperation often required: response team, land owners, state and federal agencies - human health risk: minimize risk of zoonoses
- risk to other livestock or wildlife:
-risk of antigen contamination of the environment, disease spread
-unintended exposure (birds of prey, carrion) - risk to environment:
-water supply, runoff, etc.
