ACLAM Task Force on Rodent Euthanasia 2005

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ACLAM Task Force on Rodent Euthanasia2005
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Targeted Areas

• Euthanasia of Fetal and Neonatal rodents
• Use of carbon dioxide
• Impact of euthanasia techniques on data

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Consultation with attending veterinarian is
essential
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Fetal and Neonatal Rodents

• Less than 16 weeks
• Inhalant agents not used alone
• Can be used to produce unconsciousness
• Requires some other method to ensure death

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Fetal Rodents

• Fetuses up to 15 days
• Pain perception unlikely
• Euthanasia of mother or removal of the fetus
  cause rapid death of fetus

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Fetal Rodents Continued

• Fetuses over 15 days
• Chemical anesthetics overdose
• Decapitation
• Cervical dislocation
• Can not use liquid nitrogen without anesthesia
• Can not use chemical fixation/perfusion without
  anesthesia
• Hypothermia can be used as a method of anesthesia

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Fetal Rodents Continued

• Fetuses over 15 days continued
• Inhalant anesthesia require over 40 minutes
• If fetuses not part of study, then method of
  euthanasia for mother needs to cause cerebral
  anoxia

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Neonate Rodents

• 6 days or less of age
• Hypothermia may be used for anesthesia

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Neonate Rodents Continued

• 10 days or less of age
• CO2 inhalation requires up to 50 minutes in mice
  less than 7 days
• Death must be verified
• Injection of an overdose of a chemical
  anesthetics
• Decapitation

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Neonate Rodents Continued

• 10 days or less of age continued
• Cervical dislocation
• Immersion in liquid nitrogen or perfusion
  requires anesthesia
• Anesthesia can be inhalant or Injectable
• Prolong exposure required for inhalant
• Over 10 days, treat as adult

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Summary of Method by Age
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Adult Rodents

• General Considerations
• Environmental changes
• Handling
• Removal from home cage
• Separation from cage mate
• Transportation methods
• Euthanasia chambers must be kept clean and be of
  adequate size

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CO2

• CO2 has to totally displace all oxygen
• Excess gas has to escape chamber to allow a
  gradual increase in concentration
• Opening at top that controls escape of CO2 and
  not allow reflux of room air
• CO2 should be delivered through 2 stage regulator

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CO2 Continued

• Start with empty chamber (no CO2), gradually fill
  (20 fill rate of chamber volume per minute)
• Individual rodents may become apneic at certain
  concentrations giving false impression of death
• Confirmation of death required (adjunct method
  recommended)

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Influence of Euthanasia Method on Scientific
Parameters

• Handling
• Proficiency of personnel
• Mechanical efficiency of equipment
• Species and age of animal
• Sampling sites
• Time of tissue collection

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Biological Effects of Decapitation
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Biological Effects of Decapitation
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Effects of Physical and Pharmacological
Euthanasia Methods
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Effects on Reproductive HormonesFollowing
combinations may be unsuitable for studies of
serum androgen
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Effects on Reproductive HormonesFollowing
combinations may be unsuitable for studies of
serum androgen
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Effects on Reproductive HormonesFollowing
combinations may be unsuitable for studies of
serum androgen
or
or
or
or
or
or
or
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Effects of Physical and Pharmacological
Euthanasia Methods
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Effects of Physical and Pharmacological
Euthanasia Methods
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Effects of Physical and Pharmacological
Euthanasia Methods
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Effects of Physical and Pharmacological
Euthanasia Methods
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Effects of Physical and Pharmacological
Euthanasia Methods
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Effects of Physical and Pharmacological
Euthanasia Methods
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Additional Factors That Influence The Outcome of
Euthanasia
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Gross/Histopathology Changes
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Gross/Histopathology Changes
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Gross/Histopathology Changes
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Other Information