Animals in Scientific Research 393 Decapitation without prior sedation is permissible in birds and rodents Electrical stunning without prior sedation is permissible in fish, amphibians, birds, rabbits, dogs, cats, ferrets, foxes as well as larger mammals (sheep, for example) Annex VIII of the directive provides a classification of the severity of an experiment, based on the degree of pain, suffering, distress or lasting harm expected to be experienced by an individual animal during the course of the procedure Four categories are recognised: Non-recovery ‘Procedures which are performed entirely under general anaesthesia from which the animal shall not recover consciousness shall be classified as “nonrecovery”’ Example: an animal is anaesthetised and subjected to a series of invasive procedures, after which it receives a lethal overdose of anaesthetic agent and is killed without first regaining consciousness Mild: ‘Procedures on animals, as a result of which the animals are likely to experience short-term mild pain, suffering or distress, as well as procedures with no significant impairment of the well-being or general condition of the animals shall be classified as “ mild”’ Example: an experiment of this sort may involve a small or a large number of animals (from as few as 25 animals in a pilot study to a few thousand animals in an experimental vaccine study) The procedures in this category may include repeated injections of substances by subcutaneous, intramuscular, intravenous or intraperitoneal routes on a regular basis for a period of days, weeks or months The use of gavage (where a tube is passed directly into the stomach of the animal without anaesthesia or pain relief) is also included in the ‘mild’ category In addition to the aforementioned procedures these same animals can expect to be forcibly restrained to provide blood samples at regular intervals throughout the study At the end of the study all of the animals will be killed and their tissues examined Moderate: ‘Procedures on animals as a result of which the animals are likely to experience short-term moderate pain, suffering or distress, or long-lasting mild pain, suffering or distress as well as procedures that are likely to cause moderate impairment of the well-being or general condition of the animals shall be classified as “moderate”’