Pododermatitis, more commonly known as foot pad dermatitis (FPD), is a complex problem that will affect every broiler unit at some point.
FPD is often referred to as foot pad burn due to the lesions it causes. “It is viewed to be such an important issue that it is now seen as a welfare indicator and the industry has implemented a scoring system to monitor the incidence on farm,” explains David Beavis, ABN’s national poultry specialist (see below).
Wet litter is often seen to be one of the main causes, which is why there tends to be a higher incidence in the winter.
But this is not the whole issue and ABN poultry nutritionist John Round points to management, the environment, nutrition, disease challenges and breed which all interact to cause FPD.
With wet litter being seen to be one of the fundamental causes, it is vital to consider the effects of nutrition, says Mr Round. Higher protein levels in the feed are associated with higher levels of water intake and these in turn are associated with higher moisture levels in the litter.
0 – Healthy: Very small area affected, lesions less than 2mm, slight discolouration, mild hyperkatosis
1 – Mild (pictured below): Does not extend over whole plantar pad, but substantial discolouration, superficial lesions and dark papillae
2 – Severe: Most of the plantar pad affected, with lesions on toes, ulceration, large scabs and swollen foot pad
It is also important to consider the digestibility of protein when formulating a diet, as poorly digested protein leads to an increase in nitrogen being excreted, which can increase the “burn” aspect of FPD.
Diets should also have an optimum profile of amino acids in relation to the bird’s requirements; this will improve feed conversion efficiency and help to maintain good litter condition.
“Diets high in soya, which is high in potassium, increase water intake,” says Mr Round. “Soya also contains some carbohydrates which are not readily digested by chickens, which can also add to litter problems. However, modern breeds also require higher protein levels to express their genetic potential for growth.
“The level of protein has a real bearing on how wet the litter can become. But, there is a balance to be struck to avoid reducing growth rates. This is a matter which concerns performance, welfare and also economics.”
SKIN AND GUTS
Nutritional factors also affect the strength of the skin. “Trace elements such as zinc, and vitamins such as biotin can influence the integrity of the skin. Including higher levels of these in the diet may help ensure the skin is more resilient to damage from wet litter.
“It may be worth considering a higher trace mineral inclusion in the diet during the winter months when wet litter is more of a challenge.
“Organic minerals can also positively affect skin development, and are more readily available. But these can be expensive and there are limits on the amount of zinc that can be legally added to poultry diets.”
In the past 20 years there have been major advances in the use of non-starch polysaccharide (NSP) enzymes in broiler diets. Their role in increasing the digestibility of the wheat element of the broiler diet – which leads to an improvement in the litter – has been key to NSP enzymes becoming a key component of any broiler diet.
Gut health is another important consideration, explains Mr Round. “The UK poultry industry tends to use whole wheat in broiler feeds, which helps with gut condition. Encouraging the gizzard to work harder leads to a more favourable gut microflora and, hence an increase in the overall digestibility and gut health.” Using a coarse grist in the manufacture of the feed can also help, though this can make achieving good pellet quality more difficult.
Various additives, such as prebiotics and probiotics, can also improve gut health, and some coccidiostats exert a beneficial influence.
Mr Beavis explains that there are several reasons why it is vital that the industry looks to reduce the occurrence of foot pad dermatitis.
“Besides the effects on the birds’ performance and associated welfare, it is important to consider the economic effects of FPD,” he says. “There is still a considerable overseas market for chicken feet, and the main reason for abattoir rejections of feet is FPD lesions.
There are also wider cost implications if birds are taking longer to reach their slaughter weights,” he adds.