Quantifying welfare impact of bovine respiratory disease in dairy calves via expert elicitation

Effective methods to quantify the impact of diseases on animal welfare (AW) are essential for improving health management. This study aimed to quantify the impact of Bovine Respiratory Disease (BRD) on dairy calf welfare using expert elicitation combined with the Five Domains model. The second aim was to assess whether respondents’ educational, professional, and experiential backgrounds influenced their opinions. Welfare indicators (WIs) were defined using the Five Domains Model, linking affective states to changes in physical domains. An adaptive conjoint analysis (ACA) was used to assess the average importance of WIs and perceived welfare impact. Welfare disutility (the negative welfare impact) was calculated for BRD severity scores from 0 (no clinical signs) to 3 (severe BRD). The ACA questionnaire was completed by 33 respondents, all affiliated with European research institutes or companies focused on farm animal health or welfare. Coughing was ranked as the most important WI (22.5%), followed by reduced eating time and reduced social behaviour (both 20.4%), emphasising the relevance of health, nutrition, and behavioural domains. Estimated welfare disutilities were 0.0, 3.5, 9.8, and 16.8 for BRD severity levels 0 to 3, showing a near-linear relationship between disease severity and welfare impact. No statistically significant differences in answers related to respondents’ background were observed, which made this method robust. This study demonstrates that expert elicitation combined with ACA can quantify the welfare impact of BRD, providing actionable metrics that could guide animal health and welfare management decisions.