Foot Pad Dermatitis and Hock Burn in Broiler Chickens and Degree of Inheritance

Abstract

A total of 2,118 birds from 2 strains were allocated to 12 groups of 93 to 100 each in 2 time-separated replicates. The development of foot pad dermatitis (FPD) and hock burn (HB) were recorded weekly from d 8 to slaughter on a set sample of live animals (7 per group). In addition, feet and hocks of all birds were investigated at slaughter at either 4, 6 (fast-growing strain), 8, or 10 (slow-growing strain) wk of age. Lesions were scored for both the left and right foot and classified according to a scale from 1 (no lesion) to 9 (very severe lesions) for FPD and from 1 (no lesion) to 3 (very severe lesions) for HB. No FPD lesions and very few low-grade HB lesions were found in chickens from the slow-growing strain. In the fast-growing strain, the first signs of FPD and HB were seen in wk 2. The incidence of both types of lesions increased thereafter. Foot pad dermatitis was more frequent in females (49 vs. 36%, P < 0.05). Body weight did not affect FPD, but more HB were found at higher BW (P < 0.01). Egg weight influenced neither FPD nor HB. Variance and covariance components were analyzed using a multivariate animal model, in which scores for FPD and HB were transformed into logarithmic scale. The analyses were carried out using restricted maximum likelihood algorithm. Heritabilities were estimated to be 0.31 +/- 0.12 (SE) for FPD, 0.08 +/- 0.08 for HB, and 0.38 +/- 0.13 for BW. Genetic correlations among these traits were low and nonsignificant. Phenotypic correlation between BW and FPD was low and nonsignificant and between BW and HB was 0.17 +/- 0.05 (P < 0.01). The relative high heritability of FPD and the low genetic correlation to BW suggested that genetic selection against susceptibility to FPD should be possible without negative effects on BW gain.

Influence of the provision of natural light and straw bales on activity levels and leg health in commercial broiler chickens

“…This suggests that these conditions may be partly influenced by factors other than the moisture content of the litter and the activity levels of the birds. For example, genetics may play a role in increasing/ decreasing the susceptibility of birds to pododermatitis (Kjaer et al, 2006;Ask, 2010). Higher BWs have also been linked to the occurrence of hock burn but not pododermatitis (Kjaer et al, 2006).…”

Poultry litter of wood shavings and/or sugarcane bagasse: animal performance and bed quality

“…These lesions, also known as "ammonia burns", are caused by the combination of moisture and high ammonia content of the litter (Kjaer et al ., 2006). Knee dermatitis has been positively correlated with footpad dermatitis (Meluzzi et al ., 2008).…”

Prediction of welfare outcomes for broiler chickens using Bayesian regression on continuous optical flow data

“…Hockburn is a form of contact dermatitis caused by birds sitting for long periods on wet, poor-quality litter [11,12]. Ammonia from faecal matter in the litter damages the skin and leaves black or brown lesions on the legs.…”

“…It is used as a measure of welfare in its own right because, although usually assessed post mortem, it gives an indication of the conditions that have been experienced by a bird during its lifetime [11]. The first signs of hockburn may appear as early as two weeks of age [12] and an indication that a flock that will end up with a high % of hockburn in birds after slaughter include the weight and density of the birds at two weeks [13] and high skew and kurtosis of optical flow at the same age [7]. By predicting which flocks will have later hockburn problems from optical flow information in the first few days of life, the model thus seems to be able to give a warning at a very early stage, before overt symptoms appear.…”