Development of a facial expression scale using footrot and mastitis as models of pain in sheep

Abstract

The development of a facial expression scale using footrot and mastitis as models of pain in sheep Article Title: Development of a facial expression scale using footrot and mastitis as models of pain in Trained observers reliably and accurately used the SPFES to detect pain in sheep.Treatment of disease reduced the total facial pain score of adult sheep.Total pain scores positively correlated with lesion and lameness scores.

Why Pain Is Still a Welfare Issue for Farm Animals, and How Facial Expression Could Be the Answer

“…Pathogens such as Staphylococcus aureus (Rosenbach, 1884) cause painful lesions in the teat canal [28,29], and both sheep [30] and cattle show hyperalgesia [31] in the local area. The facial expression of both sheep [32] and cattle [33] have also been observed to change in response to mastitis, with sheep showing a significant change in facial expression in response to effective treatment with antibiotics and NSAIDs [32], providing support for the painful nature of the condition.…”

“…The use of the scales also provides a more accurate assessment of the pain than the more subjective global assessment of pain [32]; this is likely due to the removal of a need to make a decision about the animal. The scales assess each part of the face and observers only need to decide on a score for each specific part, rather than the animal as a whole.…”

“…Some of these scales have also provided an intervention threshold [32], again removing the need for observers to make a decision about the need to give pain relief or not. Having a scale that can objectively identify and assess pain and provide guidance on when to give pain relief will improve the chances of that animal receiving treatment.…”

“…The tag readers will link the identification of the sheep and the image taken. Cameras will monitor the facial expression of sheep visiting these stations, learning the individual appearance over time and identifying any sheep that shows indications of abnormal feature position as described in the Sheep Pain Facial Expression Scale (SPFES) [32], alerting the farmer to any animal that registers a facial expression score at or above the pain threshold detailed in McLennan et al [32]. It also has the potential to be applied to different mammals and across different situations e.g., on farm or at market [121].…”

“…It has only been in the last decade that facial expression has been developed for use in animals as a pain assessment tool (mice [113], rats [114], rabbits [73], horses [71]), including some farm species (sheep [32,115], lambs [116] and piglets [117]). Across the different species, there are similar facial movements and action units expressed in the presence of pain, demonstrating an evolutionary stability in pain expression across mammalian species [118].…”