Recognition of pain and distress

Animals used in research and testing face physical and mental challenges, which may cause mild to severe pain and distress. Pain and distress are generally considered in the context of the analogy postulate and the precautionary principle. The analogy postulate refers to (patho-)physiological similarities between humans and vertebrates, assuming that manipulations causing pain and distress in humans do so equally in vertebrates. According to the precautionary principle, animals will be considered to have pain/distress in the absence of any scientific consensus as to the presence or absence of pain. Although those principles can be useful guides for humane treatment of laboratory animals, they do not address the subjectivity involved in recognising pain/distress. A reliable estimate of animal pain and distress can be derived from both behavioural and physiological indicators. Distress and pain are biological phenomena that motivate behaviours aimed at alleviating these states. If no behaviour achieves the expected outcome, the animal may switch to other modes, such as depression or learned helplessness. Pain is regarded as a biologically adaptive mechanism, alerting organisms to possible damage or injury. The effect of experimental procedures on perceived pain/distress may depend on physical and social environmental conditions. Observation schemes can be used to assess and monitor daily for clinical signs or problems. They can help reduce pain/distress and provide adequate care. Competent observation of animals is also basic to the correct implementation of humane endpoints. AI will transform research. Intelligent systems will generate data, enable early stress detection and improve animal welfare.