Institute for Laboratory Animal Research 1992. Recognition and Alleviation of Pain and Distress in Laboratory Animals. National Academy Press, Washington, DC.

The purposes of this book are to increase awareness of the sources and manifestations of stress and distress in laboratory animals and to increase ethical sensitivity in those who use and care for them. (It might also, indirectly, help to reduce the number of animals needed for experimental purposes: uncontrolled pain or distress can increase variability in experimental data and so require the use of more animals in a study for it to achieve statistical significance.) [p. 1] If this report improves investigators' awareness of their obligations for humane care and use of their research animals, it could even reduce the replication required to establish the generality of their scientific findings. [p. 1-2] Well-being is the absence of too much stress. It describes a positive mental state that reflects the level of welfare and comfort of an animal (Tannenbaum, 1989, p. 247). It means more than the freedom from pain and distress. [p. 3]. Stress is the effect produced by external (i.e., physical or environmental) events or internal (i.e., physiologic or psychologic) factors, referred to as stressors, which induce an alteration in an animal's biologic equilibrium. .. Some stress probably is necessary for well-being, if adaptation occurs. [p. 3] Examples of Potential Stressors That Cause Psychologic Stress: Fear, Anxiety, Boredom, Loneliness, Separation. [p. 4] Distress is an aversive state in which an animal is unable to adapt completely to stressors and the resulting stress and shows maladaptive behaviors. [p. 4] Generally, any behavior that relieves the intensity of distress is likely to become habitual, regardless of long-term effects on an animal's well-being. Examples of such behaviors are coprophagy, hair-pulling, self-biting, and repetitive stereotyped movements. [p.5] Distress results from stress to which animals cannot adequately adapt. [p. 85] Such behaviors, like maladaptive ones, should be interpreted as causing harm to the animal and producing unwanted variability in research data. [p. 86] Anxiety and Fear are emotional states that are traditionally associated with stress. [p.6] Fear is more often used to describe an emotional state that results from an experienced or known danger in the immediate environment. For instance, a dog that has gone through a painful experience in a particular setting might vocalize or try to escape when placed in that setting again. [p.6] Thus, fear usually refers to a focused response to a known object or [p. 6] previous experience, whereas anxiety usually refers to a generalized, unfocussed response to the unknown. [p. 7] The identification and control of these [environmental] stressors from the animals' or species' perspective constitute good husbandry and are a primary responsibility of all who care for or use animals in a laboratory setting. Stress produced by social isolation, social aggression, inappropriate caging, or careless husbandry practices might be manifest when an animal is used in an experiment. .. And experimental and environmental stresses are likely to cause changes in physiologic functions. .. Recognition, or anticipation, that a particular event will be perceived as an important stressor by an animal requires knowledge not only of the stressor, but of the species-typical responses to situations and of the experience of the particular animal. [p. 17] Stroking and handling by humans can be a practical and effective technique for calming animals in situations where they are distressed, particularly animals that have been positively socialized by humans. [p. 23]. It is reasonable to assume that being able to engage in positive social behaviors will contribute to an animal's comfort and well-being. [p. 23]Under the heading Spatial Architecture: For arboreal animals, perches, swings, and climbing devices can increase the effective volume of space and help to promote gross motor activity and possibly contribute thereby to the health of the animals. [p. 25] Behavioral changes, however, are the earliest signs of stress or distress that most animal care staff and researchers are likely to confront. Skilled observers who know the behavior of a particular species or strain of animal and of the individual animals under their care could provide a reliable assessment of the state of the animals. That reliability is seriously compromised when few animal care staff and researchers are afforded the time or training necessary for them to become skilled observers. [p. 50] Distress in laboratory animals is usually unnecessary and unwanted. [p. 85] This report places considerable emphasis on the importance of recognizing maladaptive behaviors resulting from stress with which an animal is unable to cope effectively as evidence of distress. Some conditions of acute stress in which an animal's behavior is normal and adaptive also suggest that intervention is warranted. Such conditions are brought on typically when an animal is strongly motivated to avoid or escape a stimulus or set of conditions. Such behaviors, like maladaptive ones, should be interpreted as causing harm to the animal and producing unwanted variability in research data. [. 86]