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  • Print publication year: 2006
  • Online publication date: November 2009

6 - Euthanasia in small animals


Only rarely does an animal experiment end in the natural death of the animal. In most cases, the animals must be killed following the completion of the experiment and certain tissue samples or organs must be collected. Even if the animal is fairly healthy after the experiment and even if it is not necessary to collect tissues, releasing laboratory animals into nature is strictly forbidden. Euthanasia is an important part of animal experimentation and every researcher who uses animals should be aware of the techniques and principles involved. There are a number of universally approved methods for euthanasia, but they may differ in different countries and different institutions even within the same country. This chapter will discuss the main methods of euthanasia. Every researcher must first consult the relevant authorities in their institution that provide permission for animal experiments, including the method of sacrifice. Only trained and competent personnel may carry out euthanasia within dedicated/suitable and approved facilities and only using methods approved by relevant authorities. Most animal facilities have veterinary physicians who are available for consultation and training purposes. The method for euthanasia should always be stated in detail in study plans and applications to the institutional body for animal care and use for scientific purposes. The method of euthanasia varies according to the animal species, number, nature of the experiment, and the intention of use of various organs for further research following death. Other animals and unnecessary personnel must not witness or hear the euthanasia procedures.

Merriam Webster's Collegiate Dictionary, 10th edn. Springfield, MA: Merriam Webster, 1994.
American Veterinary Medical Association Panel on Euthanasia. 2000 Report of the AVMA Panel on Euthanasia. J. Am. Vet. Med. Ass. 2001, 218: 669–696.
Booth NH. Inhalant anesthetics. In Booth, NH, McDonald, (eds.) Veterinary Pharmacology and Therapeutics, 6th edn. Ames, IA: Iowa State University Press, 1988, pp. 181–211.
Coenen, AM, Drinkenberg, WH, Hoenderken, R, Luijtelaar, EL. Carbon dioxide euthanasia in rats: oxygen supplementation minimizes signs of agitation and asphyxia. Lab. Anim. 1995, 29: 262–268.
Simonsen, HB, Thordal-Christensen, AA, Ockens, N. Carbon monoxide and carbon dioxide euthanasia of cats: duration and animal behavior. Br. Vet. J. 1981, 137: 274–278.
Vanderwolf, CH, Buzsaki, G, Cain, DP, Cooley, RK, Robertson, B. Neocortical and hippocampal electrical activity following decapitation in the rat. Brain Res. 1988, 451: 340–344.
Schneider, DR, Felt, BT, Rappaport, MS, Goldman, H. Development and use of a non-restraining waveguide chamber for rapid microwave radiation killing of the mouse and neonate rat. J. Pharmacol. Meth. 1982, 8: 265–274.
Ikarashi, Y, Maruyama, Y, Stavinoha, WB. Study of the use of the microwave magnetic field for the rapid inactivation of brain enzymes. J. Pharmacol. 1984, 35: 371–387.
NIH Animal Research Advisory Committee. Guidelines for the Euthanasia of Mouse and Rat Fetuses and Neonates. Available online at, 2001.