Most farm animal species are recognised as being sentient beings capable of experiencing positive and negative emotions. Animals express emotions through changes in their facial expressions, demeanour and body postures. Physiological changes, such as changes in heart rate, also occur. Experienced stockworkers use these behavioural signs to detect ill-health and poor welfare in farm animals. A number of recent studies have shown that changes in facial expressions in laboratory rodents can be used to assess the level of pain experienced by the animals. This has been extended very recently to studies in farm animal species. We are interested in being able to describe and quantify the fine detail of facial expression shown for different types of negative emotion, such as pain associated with disease in dairy cattle. Preliminary work suggested that factors such as age and breed affected facial expressions, irrespective of pain, so this must be taken into account. It would also be interesting to extend this to study positive emotions such as contentment.
