Developing measures for pain assessment in dairy calves

Abstract

Despite a growing interest in calf pain research, successful pain alleviation remains a key issue due to the challenge of accurately assessing pain. Pain constitutes a serious welfare issue owing to the prevalence of potentially painful procedures which calves undergo in the first few weeks of their lives, including disbudding in the horned breeds. At present, pain assessment is achieved using behavioural and physiological indices, none of which are gold standard, demonstrating the need to improve on these methods or search for alternatives. Thus, this thesis aimed to develop measures for pain assessment in dairy calves using their behavioural repertoire, eye blink rate and facial expression in an exploratory design. Data collection was undertaken to develop an ethogram which was used to evaluate the influence of disbudding on calf behaviour in a within subject design and the sensitive behaviours were validated against sham treated calves. Data were also collected to assess the eye blink rate patterns and changes associated with disbudding. Furthermore, changes in facial expression following disbudding were used to develop The Dairy Calf Grimace Scale (DCGS) which was validated in an online survey using 196 stakeholders blind to treatments. Relatively few behaviours were influenced by disbudding in the first three days following the procedure. An increase in the eye blink rate followed disbudding but this was comparable with the rate following sham disbudding. Based on the scores assigned by the stakeholders, the DCGS score was higher for disbudded calves than the control or their pre-disbudding score. This thesis provided data on the usefulness of calf behavioural repertoire, eye blink rate and facial expression for pain assessment following disbudding. While confirmatory studies are needed, changes in facial expression may be proposed as an alternative method of assessing pain in dairy calves.

Date of Award	27 Sept 2022
Original language	English
Awarding Institution	University of Bristol
Supervisor	Jo Murrell (Supervisor), Joanna Hockenhull (Supervisor), Suzanne D E Held (Supervisor) & Emma J Love (Supervisor)