Footpad dermatitis in Dutch broiler flocks: prevalence and factors of influence

In some European countries, footpad dermatitis (FPD) is measured as an indicator of broiler welfare. Prevalence and seasonal variation of FPD was determined within broiler flocks (fast-growing breeds) in the Netherlands. Samples were taken from 386 Dutch flocks at 8 slaughterhouses during a period of one year. Prevalence of footpad dermatitis was related to background information gathered using a food chain certification scheme to identify possible factors of influence. On average, 35.5% of the broilers had no lesions, whereas 26.1% and 38.4% had mild or severe lesions, respectively. Season, age, thinning of flocks, slaughter age, breed, slaughterhouse, and the interaction between thinning and slaughter age significantly affected severity of FPD. Peak flock FPD scores occurred in flocks where 1-d-old chicks were placed in March and December, whereas flocks placed in warm months, between June and August, displayed lower flock FPD scores. Generally, birds sent to slaughter when thinning a flock displayed less severe FPD than birds from completely depopulated flocks. Severity of FPD decreased with age. Because poultry farmer, hatchery, veterinary practice, and feed manufacturer were included in the model as random factors, it was only possible to assess their contribution relative to each other. The broiler farmer had the largest contribution. Also, a large contribution was found for hatchery, perhaps indicating that broiler quality is important. No relationship was observed between FPD and mortality. Across farms, less severe FPD was observed on farms using antibiotics. However, within farms, FPD was more common in flocks where antibiotics had been used compared with flocks that did not require antibiotic treatment. In conclusion, footpad dermatitis was frequently observed in Dutch fast-growing broiler flocks, and many factors had significant effects on severity of FPD, such as breed, thinning of flocks, age at slaughter, slaughter plant, and hatchery.