Economic evaluation of an eradication program of virulent footrot in Norwegian sheep

In 2008 virulent footrot was detected in Rogaland, a county in south-west Norway. This first known outbreak since 1948 was linked to import of live sheep from Denmark in 2005 (Gilhuus et al., 2014). Footrot is caused by Dichelobacter nodosus, were the virulent strains may cause severe disease with large impact on animal welfare and production. An eradication program, “Healthy feet”, financed by the agricultural agreement scheme and marketing fees, was initiated (Vatn et al., 2012). The purpose of the study is to investigate the economics of the program to Norwegian farmers and the sheep industry. A simulation model has been developed to portray a likely geographical spread of footrot without the eradication program but assuming farmers undertake some measures themselves (Grøneng et al., 2015). The model is based on probabilities for spreading footrot among farms within each county, mainly depending on climatic factors and distance between sheep farms. The model calculates likely spread of the disease across county borders through transport of sheep and cattle and use of common pastures. Use of common mountain pastures creates a risk of direct contagion in about 100 days annually, mostly during the gathering process in the end of the season. Outdoor feeding on pastures in the winter and use of improved local pastures in the summer increases the risk. The disease may also spread through common breeding operations like “ram circles”, animal exhibitions and selection shows while a strict limitation on trade of sheep from one county to another slows the spread. The model was parameterized with data in national databases, literature and data from the eradication program. Footrot is well known in Europe and in the UK 86% of the sheep farms reported footrot (Wassink et al., 2003). The most likely scenario, in which the number of infected flocks in Norway increases from 0.1% to 52.6% in 25 years, was selected to calculate the Net Present Value (NPV) of the eradication program. The inflation adjusted eradication costs, including associated costs and losses by the sheep holders, insurance companies, and the Food Safety Authority, aggregated to nearly NOK 70 million.