a Abbreviations: Adapted from the Report of the AVMA Panel on Euthanasia. For additional information, contact the IACUC Office.
A = Acceptable. Acceptable methods are recommended. Scientific justification for acceptable methods of euthanasia is not required in the Application to Use Vertebrate Animals in Research, Testing, or Instruction (Form 8225).
CA = Conditionally Acceptable. Acceptable methods must be considered first and excluded. Scientific or other justification for conditionally acceptable methods of euthanasia is required in the Applications to Use Vertebrate Animals in Research, Testing, or Instruction (Form 8225) and their use must be approved by the IACUC.
U = Unacceptable Without Justification. The selection of any of these methods is strongly discouraged. However, there may be unusual circumstances that may lead an investigator to choose an unacceptable method. If you must use an unacceptable method, scientific or other justification is required in Form 8225 and the use must be approved by the IACUC.
^b Intravenous sodium pentobarbital at dosages of 90-210 mg/kg is recommended for euthanasia of most species. Rats and mice may require higher dosages (120-210 mg/kg) than other species. Sodium secobarbital at dosages of` 88 mg/kg also may be used. Intraperitoneal injection may be used in situations wherein this approach would cause less distress than intravenous injections.
^c In decreasing order of preference: halothane, enflurane, isoflurane, methoxyflurane, ether. Although ether is effective it must be used with care because it is flammable and explosive and requires special precautions for safe use. Signs indicating that ether is present or in use should be posted conspicuously. To avoid explosions. the carcasses of animals euthanized with ether should be stored in explosion-safe refrigerators or freezers and should not be incinerated until the ether is volatilized. Whenever possible, most of the ether present should be permitted to volatilize before carcasses are stored in explosion-safe refrigerators or freezers.
^d Although acceptable, inhalant anesthetics are generally not used in these species because of cost and difficulty of administration.
^e Compressed carbon dioxide gas in cylinders is preferred. Flow rate should be 20% of' chamber volume/minute and chamber should be prefilled to CO₂ concentration of 70% or more before animals are placed in the chamber. If dry ice is used, freezing or chilling of animals must be prevented.
^f Use compressed carbon monoxide gas. Special procedures must be used.
^g For use with small laboratory rodents only. Specially designed equipment must be used.
^h Fish may be euthanized by immersion in a tank containing tricaine methanesulfonate at a concentration of 100-200 mg/liter of water for 10-20 minutes. Amphibians may be euthanized by immersion in a tank containing tricaine methanesulfonate at a concentration of 1-10 g/liter of water for 1 minute.
^I Fish may be euthanized by immersion in a tank containing benzocaine at concentrations greater than 100 mg/liter of water for 10 minutes or more. Larval amphibians and adult amphibians may be anesthetized by immersion in a tank containing benzocaine at a concentration of 50 mg/liter of water or 200-300 mg/liter of water, respectively. Euthanasia of larval and adult amphibians with benzocaine can be accomplished by prolonged exposure to an anesthetic dose or exposure to 2-3 times the anesthetic dose.
^j Personnel must be properly trained before using this technique.
^k Manual cervical dislocation is conditionally acceptable in mice, rats weighing less than 200 gm. and rabbits weighing less than I kg. Cervical dislocation may be performed on larger rats and rabbits manually by an individual with demonstrated proficiency or if a mechanical dislocator is utilized.
^l In amphibians and reptiles, decapitation should be followed by pithing.
^m This method is unacceptable as the sole method of euthanasia. However, if animals are first anesthetized or rendered unconscious by other means, this method may be used.
ⁿ May be used as sole method of euthanasia in species, such as frogs, with anatomic features that facilitate easy access to the central nervous system. In these species, both the brain and the spinal cord must be pithed (i.e., double pithing). In all other species of amphibians and reptiles, pithing should be followed by decapitation.
^O Horses, ruminants, and swine may be euthanized with chloral hydrate at dosages of 900 mg/kg intravenously. Sedate animal first and then give chloral hydrate intravenously. Chloral hydrate at dosages of 1100-1200 mg/kg intraperitoneally may be used for euthanasia of rodents if adequate scientific or other justification is provided by the investigator.
^p When euthanizing rats, the oxygen concentration must be < 2% and the animal must first be heavily sedated or anesthetized.
^q Stunning is unacceptable as a sole method of euthanasia. If performed properly, stunning will produce unconsciousness but must be followed by a method to ensure the animal's death (e.g., pharmacologic agents or decapitation).
^r Chloroform is unacceptable for euthanasia. It is a known hepatotoxin and suspected carcinogen and is considered hazardous to humans.