Litter quality and foot-pad dermatitis

Autumn is often a period when litter management becomes more delicate and an increase in the severity of pododermatitis is observed in poultry farms, also hock burns and tarsometatarsal lesions. The first factor associated with the appearance of pododermatitis is the humidity of the litter. Drier and softer the litter, less prone the birds are to pododermatitis and better their general well-being.

Althought the prevalence of pododermatitis has strongly decreased ; especially in Europe since the 2000s, thanks to improved breeding techniques and greater consideration for animal welfare with, notably on broiler, the implementation of Welfare regulation ; the control of pododermatitis is still a main issue.

All poultry, broilers, layers and breeders, are affected by these lesions, whatever their production method. Turkeys are more sensitive than chickens, certainly in connection with the management of litter, which is also often more difficult.

Two factors combine to trigger the appearance of lesions: the presence of ammonia, which is irritating to the skin and the humidity of the litter, which makes the skin softer and more sensitive to irritation. But it is still the moisture in the litter that is the most important factor.

The keratin layer on the epidermis forms a protective layer for the dermis below. The cells of the epidermis renew themselves regularly, which is called the turn-over of the keratonocytes. When the animal exerts its weight on a wet litter, the ammonia in the litter irritates the dermis and this starts with a discolouration of the skin of the foot’s arch, followed by inflammation and hyperkeratosis characterised by a thickening of the epidermis.  This can then lead to necrosis and even ulcers or abscesses when they develop in depth. We can therefore understand that these lesions on the pads are not of bacterial origin but they can become the entry point for bacteria present in the environment and lead to infections that can even result in mortality. In addition to the health aspect, pododermatitis also has an impact on animal behavior: through the pain due to inflammation and necrosis and also the discomfort associated with degraded litter. These behavioral and health effects affect animal performance: flocks with severe pododermatitis have lower weight gains and feed conversion rates. This is due to both poorer intestinal integrity and digestive disturbance which then leads to litter degradation and thus the development of pododermatitis. Consequently, the pain and discomfort associated with pododermatitis will increase the animals' energy requirements. It is therefore understandable that these two elements combined will have an negative impact on the feed conversion (FCR).

To control the quality of the litter and avoid its degradation, it must be sufficiently absorbent and in appropriate quantities (to be adapted according to the species and the type of soil). Good management of ventilation and environmental parameters is essential too to evacuate moisture from animal respiration, faeces and possible leaks or wastage of water. This management is particularly difficult at seasonal changes, when the settings of the computer for managing ventilation must be modified to take account of changing weather conditions.

Litter quality drift and the appearance of pododermatitis are indicators of intestinal status and possible digestive disturbance. Indeed, in the event of digestive tract imbalances, the intestinal droppings become waterlogged and undigested particles can be seen in them; the caecal droppings change in appearance from shiny black to light brown or even foamy yellow, signs of abnormal fermentation in the ceaca. These degraded droppings have a strong impact on the quality of the litter, especially if the management of the environment is not optimal. The litter then becomes damp and sometimes greasy, and is very irritating to the footpads, which is how skin lesions form.

To prevent and manage these digestive disorders, the Feedia poultry team proposes a three-step approach.

First of all, the determination of risk factors on the farm can be carried out using a tool on a PC or smartphone. The technician can thus, through observations, measurements and questions proposed by the tool, identify with the farmer the levers and areas for improvement in the farm: early water extraction, nature and temperature of the bedding, water quality, disinfection, etc.

The second axis is based on nutritional strategies specific to each species. Protein sources (secondary cereal meals, concept of ideal protein), the energy/protein balance according to physiological stages, mineral intake and phytase super dosing, feed milling and presentation are some levers for managing water consumption and the proper functioning of the digestive tract. For exemple for the granulometry of the grindings, the finer the particle size, the greater the risk of pododermatitis, in connection with the transit speeds.

Finally, we can use product made with plant extracts to maintain gut integrity, balance the microbiota and modulate the immunity of the digestive system. This can help to manage the quality of litter, limit the occurence of pododermatitis and obtain better technical results, included improved feed conversion rate.

In conclusion : the quality of litter and the prevention of pododermatitis are major issues for the performance, welfare and health of poultry.

The balance of the microbiota and gut integrity are at the heart of this issue, in witch the  technical management of the poultry houses and the formulation of feed, both in terms of nutritional levels and composition, play an important role.

Virginie RYCKEBOER, poultry specialist FEEDIA, Techna France Nutrition ; virginie_ryckeboer@techna.fr

Martin DALY, managing director UK & Ire, Techna Ireland Nutrition ; martin@technaireland.com