Validation of histological and visual scoring systems for foot-pad dermatitis in broiler chickens

Abstract

In this study, an appropriate visual scoring system for foot-pad dermatitis was validated, considering the histologically measured depth of the inflammation zone and the histopathological grade (no lesion, mild lesion, ulcer). The aim being to evaluate whether the visual, macroscopic scoring of foot-pad dermatitis can represent the histological, microscopic findings. Two hundred Ross 308 broiler chicken feet (birds aged 39–42 fattening days) were collected at a slaughterhouse and scored macroscopically according to a modified version of the Welfare Quality® Assessment Protocol for Poultry. Afterwards, 200 histological slides (one per foot) were prepared, the extent of the inflammation measured and all slides scored by veterinarian pathologists using Michel et al's modified scheme. The statistical relationship between microscopic and macroscopic score and depth of inflammation were estimated via regression models. Increasing macroscopic score was found to be linked with an increase in microscopic score and the depth of inflammation. In particular, feet without lesions and feet with ulcers were identifiable using the macroscopic score. Macroscopic scoring of foot-pad dermatitis can mirror histological findings once certain limitations are taken into account (superficial lesions were not clearly identifiable). Foot-pad dermatitis is considered a useful indicator of animal welfare and our findings suggest that visual, macroscopic scoring could be a practicable assessment tool.

Walking on Tiptoes: Digital Pads Deserve Increased Attention When Scoring Footpad Dermatitis as an Animal Welfare Indicator in Turkeys

“…According to a study by Stracke et al ( 14 ), there is a link between the occurrence of ulcerations and the size of the lesion on the metatarsal pad, findings which are in agreement with Toppel et al ( 13 ). Similar results were observed for broiler chickens ( 19 , 20 ). However, using the standard scoring system of Hocking et al ( 11 ), the study by Stracke et al ( 14 ) also showed that no differences in severity of ulcerations were found between the higher scoring levels (scoring levels 2, 3, and 4).…”

“…Even if included in some of the studies evaluating FPD in turkeys ( 1 ) and in assessment schemes in Germany ( 6 ), the digital pads are currently not included in the evaluation when using standard scoring systems for practical applications ( 9 , 11 ). In contrast to turkeys, scoring systems used in broilers partially include lesions on the digital pads ( 20 ) though only in the highest severity grades. According to the literature ( 11 , 21 , 22 ), the assumption was that with rising severity grades of altered lesions on the metatarsal pad, alterations on digital pads would increase alike.…”

Automatic Scoring System for Monitoring Foot Pad Dermatitis in Broilers

“…They vary in the number of score categories and the approach of the assessment. In most of the scoring systems, three [10][11][12], four [13,14] or five [15][16][17] categories are used for the classification of FPD. In some systems, especially the size of the FPD, lesions are considered [16], whereas other systems consider the depth or severity of FPD [13,14].…”

“…In most of the scoring systems, three [10][11][12], four [13,14] or five [15][16][17] categories are used for the classification of FPD. In some systems, especially the size of the FPD, lesions are considered [16], whereas other systems consider the depth or severity of FPD [13,14]. In Germany, officials at slaughter can use a three-or four-point scoring system to evaluate FPD in broilers [18,19].…”

“…In Germany, officials at slaughter can use a three-or four-point scoring system to evaluate FPD in broilers [18,19]. Piller et al [16] recommended a three-category classification of FPD for the identification of ulcers, whereby lesions larger than 0.5 cm in diameter have a high probability of consideration as a "deep" lesion.…”