Effects of eggshell conductance and incubation temperatures on duck footpad development

Footpad dermatitis (FPD) is a major animal welfare and economical concern. A field trial was conducted to evaluate the effects of eggshell conductance (G) and incubation temperature profiles (TEM) on duck footpad skin structure at hatch and 35 d of age, and their influence on probability to observe FPD scores under commercial conditions. A total of 10,000 Pekin duck eggs were assigned to 4 treatments, resulting from a combination of two G, reduced and normal, and two TEM, elevated and normal. At hatch, 6 ducklings from each treatment were weighed and footpad skin samples collected for histological processing. The remaining ducklings were placed in a commercial house. At 35 d, 5 drakes and 5 hens from each treatment combination were weighed and classified for FPD using a 3-level scale to determine probabilities to observe each score using logistic regression. Additionally, footpads of 7 ducks per treatment combination were sampled for histological analysis. Data were analyzed as a CRD with 2×2 factorial arrangement of treatments. There were no effects of treatments on BW at hatch and 35 d. High TEM and reduced G increased residual yolk. On footpad skin layer measurements, an interaction effect was observed on dermis length and area and total papillae height at hatch. At 35 d reduced G ducks had more area of epidermis than normal G. Additionally, either elevated TEM or reduced G tended to increase the probability (P<0.10) of having FPD. The stratus corneum was not affected by treatments. In conclusion, G and incubation TEM have an effect on footpad skin structure development during embryo development, and this might be related to FPD in ducks at market age.