Overall there is no pain indicator that can be considered ‘gold standard’ in the way verbal communication is in humans, and indicators should be chosen on a case-by-case basis.
Pain has evolved to motivate an animal to withdraw from a dangerous and damaging situation, to allow healing and to prevent being caught in a similar situation in the future. The main causes of pain in cattle are common management practices e.g. castration and disbudding and injuries from other cows, inflammatory diseases and parturition. Animals need and deserve to have their pain managed and alleviated, and it is the legal responsibility of those looking after them to do so. Pain assessment is therefore crucial. Pain assessment methods can be used in both a clinical and research setting. The two main categories of pain assessment are physiological and behavioural indicators. Physiological indicators include the measurement of biomarkers to determine the presence of pain; biological indicators are the animal’s, sometimes subtle, responses to noxious stimuli. An ideal indicator of pain would be valid and specific to pain, reliable and sensitive.
This study collated data from 187 papers published in the last 20 years which utilise pain assessment methods in cattle in order to determine which indicators are more ideal. A total of 591 indicators of pain were identified of which 285 were physiological and 306 were behavioural. Acute pain was assessed more frequently than chronic pain and overall more papers assessed pain in calves than in adult cows. There were limitations in that not all papers looking at pain assessment in cattle were included in the study as a result of access limitations or not appearing in the search