Pain and Distress Assessment and Reduction
Stress is a normal feature of life for all animals and serves important adaptive functions, such as the ability to flee from harm, hunt for food, mate, and interact socially with other animals. Animals used in research are subject to many stressors that are not normal, and under circumstances that do not offer normal adaptive responses.
Distress occurs when an animal is unable to adapt completely to a stressor.
Animals may exhibit distress by showing specific behaviors, however, some animals hide fear and distress. In addition, distress is usually accompanied by biochemical and physiological changes, and it is therefore critical that protocols be designed to minimize the possibility of stress on the animals.Behavioral, biochemical, and physiological changes indicative of distress can markedly affect research data; therefore, preventing distress in research animals is of prime importance, from both a humane and a research standpoint.
Possible stressors for animals being used in research:
- inadequate space and overcrowding
- social hierarchy
- social deprivation
- lack of environmental conditions needed for species-specific behaviors (e.g., gnawing for rats, exercise for dogs)
- inappropriate handling and restraint
- high-intensity lighting
- irregularities in temperature, humidity, and light cycles
- diet and feeding schedules
- experimental procedures
- and more
An animal's response to a stressor can vary depending on age, sex, past experience (e.g., handling, previous experimental procedures), genetic profile, and physiologic state.
Ways to reduce or eliminate distress
- pay careful attention to animal husbandry (i.e., light, temperature, humidity, caging, bedding, etc.)
- provide species-appropriate environmental enrichment (in some species, this is mandated by law)
- provide social housing for social species
- provide training (of people AND animals)
- handle gently and quietly
- limit stressors imposed on an animal
- use anesthetics, analgesics, and anti-inflammatory drugs for intra- and postoperative or experimentally induced pain
Although we cannot know exactly what an animal perceives as painful, the rule of thumb is to consider any stimulus we humans would consider painful as also painful to animals.
Use of anesthetics and analgesics
- is required by law unless withholding is scientifically justified and IACUC-approved
- should be planned in consultation with an RARC veterinarian
- must be included in animal-use protocols
Using paralytic drugs is not permitted without anesthesia.