Footpad Dermatitis in Broilers: Differences between Strains and Gender

ABSTRACT Pododermatitis, also known as "bumblefoot", is an inflammatory lesion of the footpad. The objective of this study was to evaluate the influence of genetic strain and sex on the incidence of footpad lesions in broilers. The experiment was carried out at São Paulo State University, using 480 broilers distributed in a completely randomized experimental design in a 2X2 factorial arrangement (2 strains X2 sexes), with four replicates of 30 broilers each, totaling 16 experimental units. Feed intake, weight gain, feed conversion ratio, and livability were evaluated at 21, 35 and 42 days of age; production efficiency factor was determined at the end of the rearing period. On day 42, the footpads of 100 broilers were grossly examined and assigned a lesion score in a 1-3 scale (Almeida Paz & Martins, 2014). Three samples per score within treatment were collected for microscopic evaluation. Analysis of variance was applied and performance parameter means were compared by Tukey's test. Footpad lesion incidence was analyzed by the c2 test using SAS (version8.2). Ross(r) broilers presented higher feed intake during all evaluated periods, and higher weight gain only in the period 1 to 21 days compared with Cobb(r) broilers. On the other hand, Cobb(r) presented better feed conversion ratio in the periods of 1 to 35 and 1 to 42 days. The incidence of foot pad lesions was statistically different (p< 0.05) between strains and sexes, but there were no interactions between these factors. The lesion scores assigned were compatible with the histopathological results, showing that the higher the score, the more severe were the dermal and epidermal lesions.