A review of the aetiology and possible causative factors of foot pad dermatitis in growing turkeys and broilers

FPD is a common condition amongst commercially grown turkey poults. It causes the skin of the footpad to become hard and scaly, often developing horn-like pegs of abnormal keratin. The footpad can become swollen, frequently splitting. In the centre of the lesion the epidermis separates, and is often totally necrotic. Heterophils filter into the stratum germinativum. The cause of FPD is complex, but many contributing factors have been suggested, such as dietary intake, skin structure, bird weight and sex, litter moisture and litter type. Litter quality is affected by many other factors such as stocking density, air temperature and moisture, season, consistency and amount of faeces (affected by diet), and drinker design. Wet litter is the most likely factor affecting FPD, followed by biotin deficiency. Experimental evidence suggests that biotin deficiency causes FPD, and that commercial rations do not contain enough biotin to prevent these lesions. Supplementations of biotin have been shown to reduce the severity and incidence of lesions. Wet litter has also been identified as a possible causative agent. Broilers and poults reared on wet litter have an increased incidence and severity of FPD lesions, but the problem is alleviated by replacing the wet litter with dry. Biotin supplementations are able to reduce FPD to a certain extent if birds are reared on dry litter, but if on wet litter, lesions may still occur. Biotin intake and wet litter appear to be the factors most likely to influence the development of FPD. Experimental results are difficult to compare because rearing conditions differ. Further experimentation is needed to determine the optimum amount of biotin required for healthy growth and lesion free foot pads, and to ascertain the real effects of other suggested causes.