Spatial aspects of foot-pad dermatitis in Swedish broilers

This study aimed at analysing spatial and spatio-temporal aspects of foot-pad dermatitis in Swedish broilers. The information on disease prevalence and severity was based on a two-year fool-health surveillance programme where information on producer, breed, feed manufacturer, region, abattoir, date of slaughter and several other variables was recorded. The level of clustering in space was analysed on 2-digit zipcode level using Moran's I test which measures similarity of location. The level of clustering in space was also analysed using the I-pop test, which takes the population at risk into consideration. The examination of time-space interaction was carried out using the Barton method and the Knox method. We found a significant (p<0.001) clustering of regions with respect to foot-pad dermatitis score using Moran's I test, and a significant (p<0.0001) clustering in space also when related to the number of flocks delivered from each region. The flocks with very high prevalence of foot-pad dermatitis were significantly (p<0.05) clustered in both time and space, i.e. the flocks with high prevalence of lesions came from the same geographic area during the same time periods. This information will permit us to focus the control efforts within the foot-health surveillance programme on specific regions in specific time periods, thus making the programme more effective.