Application of Methods to Assess Animal Welfare and Suffering Caused by Infectious Diseases in Cattle and Swine Populations

SIMPLE SUMMARY: Infectious disease control in livestock is often motivated by food safety concerns and economic impact. However, most diseases also affect animal welfare. We established an approach to quantify the welfare effect of infectious diseases in cattle (three diseases) and pigs (two diseases). A “suffering score” was established based on the aggregation of severity, duration, and frequency of clinical entities of the diseases. The resulting suffering scores were then used to compare the welfare impact of the different diseases and for comparison to other common welfare hazards. For example, the approach suggested that bovine viral diarrhoea and paratuberculosis are more severe for cattle than infectious bovine rhinotracheitis. In pigs, porcine reproductive and respiratory syndrome has a much bigger welfare impact than Aujeszky’s disease, assuming all diseases remain endemic. ABSTRACT: Control of infectious diseases in livestock has often been motivated by food safety concerns and the economic impact on livestock production. However, diseases may also affect animal welfare. We present an approach to quantify the effect of five infectious diseases on animal welfare in cattle (three diseases) and pigs (two diseases). We grouped clinical manifestations that often occur together into lists of clinical entities for each disease based on literature reviews, and subsequently estimated “suffering scores” based on an aggregation of duration, frequency, and severity. The duration and severity were based on literature reviews and expert knowledge elicitation, while frequency was based mainly on estimates from the literature. The resulting suffering scores were compared to scores from common welfare hazards found under Danish conditions. Most notably, the suffering scores for cattle diseases were ranked as: bovine viral diarrhoea and infection with Mycobacterium avium subsp. paratuberculosis > infectious bovine rhinotracheitis, and for pigs as: porcine respiratory and reproductive syndrome > Aujeszky’s disease. The approach has limitations due to the limited data available in literature and uncertainties associated with expert knowledge, but it can provide decision makers with a tool to quantify the impact of infections on animal welfare given these uncertainties.