Abstract
The assessment of pain in cattle is hindered by the difficulty of communication between species and the possibility that prey species, such as cattle, limit behaviour indicative of pain due to the danger of predation. To identify behavioural and physiological responses caused by the pain of any surgical procedure, injury or disease, it is necessary to compare the responses of animals that have received or not received effective local anaesthesia or analgesia. Few such studies have been carried out. The responses of animals to any injury may be due to irritation, dysfunction or be part of the convalescence process and may not be caused by pain per se. Specific behaviours may indicate pain following specific injuries. The pain caused by different injuries may evoke specific behaviours so many sets of observations are required to define the behaviours evoked by pain. Head and tail shaking and the lack of grooming and rumination are useful indicators of pain after dehorning but there is a need to quantify whether these behaviours are useful indicators of pain following other injuries by further behavioural observational studies. Generally, behaviour is most useful in a clinical situation. However, physiological responses to different procedures, such as the plasma cortisol response, can be used to compare the relative painfulness of different experiences under experimental conditions and the results of this type of research can then be used clinically. Changes in productivity and immunocompetence during and following a painful experience are probably not useful tools to measure pain. Behaviour and physiological responses are useful ways to assess acute pain but there are problems with the assessment of chronic pain. The response of cattle to specific stimuli (mechanical, pressure and thermal) may be useful to measure chronic pain. Much work is required to confirm that specific behaviours or the absence of them are useful general indicators of pain in cattle and to identify those behaviours which may be useful indicators of pain after specific injuries.