Euthanasia

Definition

A gentle death that is regarded as an act of humane killing with the minimum of pain, fear and distress.

Objectives

  • Painless
  • Unconsciousness and death are achieved rapidly
  • Minimal restraint and psychological stress
  • Simple, reliable, reproducible and irreversible
  • Safe for the operator

Clinical Endpoints

"In experiments involving animals, any actual or potential pain, distress or discomfort should be minimized or alleviated by choosing the earliest endpoint that is compatible with scientific objectives of the research. "
- CCAC, 1998

The clinical endpoint lists the conditions, complications and criteria that would lead to euthanasia of an animal before the expected completion of the experiment, e.g. more than 20% weight loss, maximum tumour size, vocalizing, and lack of grooming.

Experimental Endpoints

The experimental endpoint, is the estimated survival time for the animals.

Reasons for Euthanasia:

Humane endpoints

  • Levels of pain, distress and suffering exceed acceptable limits
  • Specific guidelines for physiological parameters (weight loss, reduced mobility, alterations in core body temperature etc.)
  • Specific guidelines for certain areas of research (neoplasia, toxicology)

Experimental endpoints

  • Experimental objectives / results are achieved
  • Tissue harvesting
  • No longer suitable for breeding
  • Unwanted genotype / phenotype
  • Questionable / undesirable health status

Recognition and Confirmation of Death

  • Cessation of heartbeat and respiration
  • Absence of all reflexes
  • Central, fixed dilated pupil (easier to detect in larger species)
  • Chemical and physical methods

Acceptable Methods of Euthanasia

  • Species dependent
  • Methods differ for anaesthetized vs. unanaesthetized animals
  • Physical methods must cause immediate loss of consciousness through physical trauma to the brain

What best describes a good method of euthanasia is that it consistently produces a humane death.

  • For chemical euthanasia, the intravenous route is always preferable to intraperitoneal route due to rapid induction and a quick, humane death.
  • For physical euthanasia, prior anaesthesia is mandatory. If there is no anaesthesia administered prior to a physical means of euthanasia, scientific justification must be provided, with subsequent approval by the local Animal Care Committee.

FISH

Chemical methods

  • Tricaine methane sulfonate (MS 222) immersion overdose. Neutralized to pH 7.5 with bicarbonate
  • Benzocaine immersion overdose. Neutralized to pH 7.5 with bicarbonate

Physical methods

  • Concussion followed by exsanguination, removal of the heart or cervical dislocation

Anaesthetized fish

  • Pithing
  • Decapitation
  • Exsanguination

AMPHIBIANS

Chemical methods

  • MS 222 immersion overdose. Neutralized to pH 7.5 with bicarbonate
  • Benzocaine immersion overdose. Neutralized to pH 7.5 with bicarbonate
  • Sodium pentobarbital overdose (intravenous, IV or intraperitoneal, IP)

Physical methods

  • Concussion followed by pithing
  • Decapitation and pithing

Anaesthetized amphibians

  • Pithing

REPTILES

Chemical methods

  • Sodium pentobarbital overdose (IV or IP)

Physical methods

  • Captive bolt followed by destruction of brain

Anaesthetized reptiles

  • Pithing
  • Decapitation

Note: For amphibian and reptilian species, inhalational anaesthetics are an unacceptable means of euthanasia due to breath holding capacity, resulting in prolonged induction times.

BIRDS

Chemical methods

  • CO2 (in chicks up to 72 hours old)
  • Volatile inhalational anaesthetic overdose
  • Sodium pentobarbital overdose (IV or IP)

Physical methods

  • Concussion followed by exsanguination or decapitation

Anaesthetized birds

  • Decapitation
  • Pithing
  • Potassium chloride

Note: exsanguination is unacceptable in birds due to rapid blood clotting

RODENTS

Chemical methods

  • Sodium pentobarbital overdose (IV or IP)
  • Inhalation anaesthetic overdose
  • Isofluorane followed by CO2 inhalation (animals more than 10 days old)

Physical methods

  • Microwave irradiation in specially designed units

Anaesthetized rodents

  • Cervical dislocation
  • Decapitation
  • Rapid freezing
  • Exsanguination

RABBITS

Chemical methods

  • Sodium pentobarbital overdose (IV or IP)
  • Inhalation anaesthetic overdose – prior sedation mandatory

Anaesthetized rabbits

  • Exsanguination
  • Potassium chloride

CARNIVORES (dogs, cats, ferrets)

Chemical methods

  • Sodium pentobarbital overdose (IV only) – prior sedation mandatory
  • Inhalational anaesthetic overdose – prior sedation mandatory

Physical methods (field conditions only)

  • Stunning

Anaesthetized carnivores

  • Exsanguination
  • Potassium chloride

LARGE MAMMALS (pigs, sheep, goats, cattle)

Chemical methods

  • Sodium pentobarbital overdose (IV only) – prior sedation mandatory
  • Inhalation anaesthetic overdose (lambs and kids only) – prior sedation mandatory

Physical methods (field conditions only)

  • Captive bolt followed by exsanguination
  • Free bullet humane killers
  • Stunning

Anaesthetized large mammals

  • Exsanguination
  • Potassium chloride

NON-HUMAN PRIMATES

Chemical methods

  • Sodium pentobarbital overdose (IV only) – prior sedation mandatory

Unacceptable Methods of Euthanasia for All Species

Air embolism

Burning (chemical or thermal)

Carbon monoxide

Chloral hydrate

Chloroform

Cyanide

Decompression / vacuum

Drowning

Diethyl ether

Exsanguination without anaesthesia

Formalin

Household products and solvents

Hypothermia / hyperthermia

Ketamine

Magnesium sulfate

Methoxyflurane

Narcotics

Neuromuscular blocking agents

Nitrous oxide

Rapid freezing without anaesthesia

Removal from water (gilled vertebrates)

Strangulation

Strychnine

   

 

 

 

End of the BASIC LEVEL theory course material.

If you do NOT need the Advanced Level and you do NOT need the Wildlife in Laboratories and/or Wildlife in the Field, you are now ready to take the test. To request the test, please email the animalcare [at] mcgill.ca (Training Advisor) (the test is requested, received and submitted by email).

Please note that EACH participant must make the request using his/her own email account. The participant must identify in which investigator’s lab they are working or the course title for which this test is a requirement (if applicable). 

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