TEMPORAL ASPECTS OF FOOT-PAD DERMATITIS IN SWEDISH BROILERS

This study aimed at analysing the temporal aspects of foot-pad dermati tis in Swedish broilers. The information on disease prevalence and sev erity was based on a 2-year foot-health surveillance programme where i nformation on producer, breed, feed manufacturer, region, abattoir, da te of slaughter and several other variables was recorded. The seasonal effects were evaluated using classical multiplicative decomposition t ime series analysis. This study shows that there has been a significan tly consistent decrease in the prevalence of severe foot-pad lesions d uring the first 2 years of the programme. Looking at the development o ver time we found a trend-cycle component of 10.4% and a seasonal comp onent of 48.7% resulting in a total adjusted R-square value of 58.5% f or the total foot-pad score. This means that almost 60% of the variati on in flock foot-pad score can be explained by the variable 'time', an d that this variation was mainly related to seasonal effects but also to a general decreasing trend over the study period. However, substant ial differences in temporal patterns among slaughterhouses, feed suppl iers and regions were found. The time series analysis approach was fou nd to be useful for this type of investigation when evaluating the eff ects of an intervention programme, and it can also be applied for proj ecting the future development of disease status in a stable population .