394 A Menache Example: major surgery under general anaesthesia, such as organ transplantation, where the animal is allowed to recover and subsequently subjected to multiple additional procedures associated with such surgery Such experiments may last from a few weeks to several months The animals will be killed at the end of the study and their organs and tissues examined Severe: ‘Procedures on animals as a result of which the animals are likely to experience severe pain, suffering or distress, or long-lasting moderate pain, suffering or distress as well as procedures, that are likely to cause severe impairment of the well-being or general condition of the animals shall be classified as “severe”’ Example: the experimental induction of inflammation of the brain in a group of animals in order to test a new drug against a human disease The animals are expected to suffer severely as a result of the inflammation of the nervous system, including paralysis, and some may die in extremis before the end of the study Although researchers may choose to euthanase animals that are moribund, animals that are moribund ‘out of hours’ will not be euthanased at night nor possibly during weekends due to reduced human supervision on those occasions It should be noted that the above classification does not take into account the psychological stress and fear imposed on an animal as a result of its incarceration in a cage (in some cases, in solitary confinement), its inability to move freely, to express normal behaviour and separation from family groups Studies have shown that routine laboratory procedures, including handling and blood collection, are an additional source of increased stress to the animals (Balcombe 2004) It should also be noted that the killing of an animal in a ‘non-recovery’ procedure is de facto less significant than using a live animal in a ‘mild’ procedure, in the context of the severity classification In other words, taking away an animal’s life counts for less than, subjecting an animal to a mild procedure Finally, the severity classification largely ignores cumulative suffering For example, a monkey may require several months of forced training in order to correctly perform a cognitive task The training regimen will entail several hours of restraint in a primate chair five days a week for a period of weeks to months, in combination with periodic food and water deprivation Once the monkey has completed the training regimen the actual experiment will begin This could involve invasive brain surgery, either to deliberately destroy selected parts of the brain or else to permanently implant brain electrodes, after which the monkey will spend a few more weeks watching