Euthanasia

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Euthanasia

• A gentle and easy death

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Euthanasia

• The bringing about of a gentle and easy death.
• Humane killing with the minimum of pain, fear and
  distress.

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Why carry out euthanasia?

• End of experiment
• Continuing adverse effects
• Pain, distress or suffering exceeding stated
  level
• If state of health or welfare give cause for
  concern
• Unwanted stock
• For blood or other tissues

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Legislation

• 86/609/EEC
• Schedule 1 to Animal Scientific Procedures Act
  (U.K.)
• Both exclude killing of an animal from the legal
  definition of an experiment if carried out in
  accordance with specified guidelines.

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Humane method of killing

• "The killing of an animal with a minimum of
  physical and mental suffering, depending on the
  species."

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Requirements

• Minimise fear and distress.
• Separate area away from other animals.
• Ensure operator competence.
• Reliable method.

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Minimise fear and distress

• Adequate and gentle restraint.
• Calm, caring and confident approach.
• Any traces of blood / excreta from other animals
  fully removed.

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Ensure operator competence

• Full training required practice on cadavers
  first.
• Experience in handling essential.
• Should be fully familiar with all equipment used.
• Should feel confident before doing it alone.
• Back-up plan if something goes wrong.
• Capable of confirming that death has occurred.

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Method

• Painless and stress free.
• State of unconsciousness should be reached
  rapidly and maintained until death.
• Easy to administer.
• Safe for staff who perform it.
• Appropriate for species, bodyweight, and stage of
  development.
• Compatible with experimental objectives.

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Choice of method

• Chemical or physical.
• Chemical usually overdose of anaesthetic by
  inhalation or injection or CO2 asphyxia.
• Physical concussion, decapitation or cervical
  dislocation.

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Chemical methods

• Inhalation anaesthetic
• Suitable for small rodents NOT rabbits.
• Halothane or Isoflurane NOT chloroform or ether.
• Vapourising unit with gas scavenging gives better
  induction and is safer for operator.
• Can use glass jar but slower, more stressful
  induction must avoid contact between animal and
  liquid anaesthetic.

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Chemical methods

• Injectable anaesthetic
• Usually barbiturate (sodium pentobarbitone) i/v
  or i/p.
• Triple strength (200mg/kg) recommended for i/v
  but need to dilute this for i/p administration.
• Fast, safe and effective for the majority of
  animals.

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Chemical methods

• CO2 asphyxia
• Suitable for rodents and birds up to 1.5kg.
• Not suitable for rabbits, diving animals or
  neonates.
• Prefill chamber with gt70 CO2.
• Limit the number of animals to ensure exposure.
• Chamber should have transparent viewing panel.
• Empty out residual gas and clean thoroughly when
  finished.

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Physical methods

• Concussion
• Suitable for rodents, rabbits, birds, reptiles,
  fish and amphibians up to 1kg.
• Must be followed by immediate cervical
  dislocation or exsanguination and confirmation of
  death.
• Rapid and effective when carried out by trained,
  competent personnel.
• Aesthetically unacceptable for most people.

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Physical methods

• Cervical dislocation
• Suitable for rodents up to 500gm, rabbits up to
  1kg and birds up to 3kg.
• Stunning/sedation essential for larger animals
  (gt150g ?)
• Rapid and effective.
• Must confirm dislocation and death immediately.
• Aesthetically unacceptable for most people.
• Should be used only if operator totally confident.

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Physical methods

• Decapitation
• Suitable for small rodents, embryos and neonates.
• Other methods preferred - delayed loss of
  consciousness.
• Guillotine preferable animal should be
  restrained in polythene sleeve.
• Scissors less effective must ensure that
  sharpness and adequate blade length.
• Cold blooded vertebrates and birds should be
  rendered insensible beforehand.

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Confirmation of death

• Absence of pulse / heartbeat.
• Decapitation.
• Destruction of brain.
• Severing of major blood vessels to terminate flow
  of blood to brain.
• Onset of rigor mortis (return to individual cage
  for c.30 mins).

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Foetuses and neonates

• Functional brain (pain perception) at 60
  gestation.
• Inhalation anaesthetics administered to the dam
  may not anaesthetise the foetus.
• Decapitation, concussion or injectable
  anaesthetic.
• CO2 unsuitable.

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Euthanasia of Rodents
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Euthanasia of Rabbits