Measuring pain in dogs and cats using structured behavioural observation

•Measuring pain is crucial for effective pain management and a requirement of evidence based medicine.•Important to measure the affective (‘how it makes you feel’) component of the pain experience, not just intensity.•In acute pain the veterinary surgeon or nurse is the animal’s proxy while in chronic pain the owner assumes that role.•We measure chronic pain in man and animals by quantifying its impact on health — related quality of life (HRQL).•Validity, reliability and responsiveness are key properties of HRQL instruments as is utility (user friendliness). The contemporary approach to pain measurement in people and animals seeks to measure the affective (emotional) component of the pain experience using structured questionnaires with formal scoring methodology. Chronic pain has wide-ranging impacts which affects the quality of life (QOL) of the individual, whether that is a person or an animal. Accordingly instruments to measure chronic pain are designed to measure its impact on QOL and are called health-related quality of life (HRQL) instruments. In veterinary science instruments to measure pain are based on behavioural observation by the veterinary surgeon/nurse in the case of acute pain and by the owner in the case of chronic pain. The development of HRQL instruments is an expanding field in veterinary science, not just for the measurement of pain, but for other chronic diseases, and it has a wide application in pharmaceutical research and clinical practice to improve patient care. This review highlights the challenges involved in creating such measures for dogs and cats, seeking to provide the reader with an understanding of their development process. It then provides an overview of the current status with regard to acute and chronic pain measurement.