Broilers

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Litter management – Part 2: Litter condition strongly depends on good management

Good flock performance for birds that are kept on floor systems, starts with selecting good litter. Once the birds are in the house, the litter should be kept in excellent condition in order to keep them in good shape. Under certain conditions, reuse of litter is even possible.

As birds grow older or when they are over stocked the density becomes too high for the quantity of litter, leading to a greater build-up of water admixed with nitrogenous products. Overstocking also reduces scratching rates and should, therefore, have detrimental effects on the litter. This problem may also arise from a disease problem such as lameness even with light stocking, since birds will not be able to scratch the litter sufficiently.

Laying stock getting to near peak production produce greater amounts of estrogenic hormones in their bodies. This is often associated with increased consumption and utilisation of water to the point that excess will be excreted. Sufficient supply of quality litter should, therefore, be available during that period, and mixed with some absorbents such as sand or other suitable materials.

Litter management – Part 2: Litter condition strongly depends on good management
Birds will do well if they are kept on litter which is in good condition.

The costs of poor litter conditions on broiler producers are estimated in Table 1. These estimates are based on one flock in a single broiler house with a capacity of 20,000 birds. Obviously, these costs are a rough approximation and have been made very conservatively to avoid over-estimation. Actual losses are likely to be much greater.

Use of chemicals

Formalin could be used against microbes which break down nitrogenous compounds in faeces and urine and release ammonia. Addition of formalin to the litter at 3% was found to reduce the microbial population in the litter from 115 to only 1.3 cfu/gram. As a result, the ammonia level was reduced from 100 to 5 ppm for a period of three weeks following the treatment.

Acidification also improves litter quality and hence improves performance of chickens. In one study, a mixture of sodium lingo-sulfonate, propionic acid, and formic acid was sprayed on the litter at a rate of 7% of the litter weight. The acid treatment has reduced humidity and microbial counts of the litter. As a result, microbial count in the gut was also reduced and growth of chickens was improved at similar intake levels (Figure 1). The improved growth here was probably due to the decreased activity of the bile salt hydrolase as the number of gut micro flora decreased. The reduced number of gut micro flora also reduces the risk of developing clinical or subclinical necrotic enteritis which affects growth.

Mineral compounds such as lignite (a compound containing Fe2O3, SO3, P2O5, Mn3O3, Al2O3, MgO, CaO, and SiO2) could also be used to improve litter conditions (Figure 2). Performance studies with lignite added to the litter at 9.5 kg/m3 reported increased weight gain and feed efficiency of broiler chicks through eight weeks of age. With laying hens there were 1.5% increase in egg production and 1% increase in hatchability resulting from addition of lignite to the litter at a similar rate.

Physical treatment

The use of ultraviolet/short wave light operating at 400 nm per m2 of the house area has proved to be effective against a wide range of bacteria and fungi (Figure 3). This is particularly so at the top layer of litter, but at deeper layers the microbial population may remain unaffected. It is often recommended that the UV treatment be used only before arrival of chicks, to avoid any adverse effects on health or activities of birds.

An alternative method is to heat the litter with water maintained at 50-70°C and flowing in PVC pipes. The water pipes are to be installed evenly at various floor locations just above the litter or beneath it. This method could be used safely while the birds are in the house. Studies of heat-treated litter revealed improved conditions with respect to microbial population, ammonia level, and moisture content of litter.

Reuse of litter

The reuse of poultry litter has become a common practice, particularly with broilers. It saves labour and costs, since several broods of broilers can be raised on the same litter. Reuse of litter also has a nutritional advantage. In the bacterial action that takes place, there is a considerable synthesis of B-complex vitamins, including vitamin B12. Except when the ration has an ample supply of these vitamins, the growth of chicks or the egg production of hens may be appreciably increased by keeping them on reused litter. Such responses may only be obtained with a definite determination that the litter is clean and has no disease organisms.

Litter management – Part 2: Litter condition strongly depends on good management
If managed properly, litter can be safely used for a number of rounds of broiler chicks.

Infected litter, on the other hand, may give troubles from coccidiosis or from round worms if reused to raise a new brood of chicks. Also, inflammation of the cornea of the eye may occur in young chicks started on such an old litter, especially when it is damp. This is caused by ammonia which may be present in the litter. Under these circumstances, performance of chicks may be negatively affected. In a recent study, the new litter gave an average body weight of 1895 grams and old litter 1757 grams with feed conversions of 2.01 and 2.18, respectively.

Well managed litter can be safely used for many (four or more) broods of broiler chicks. One management tool is to make sure that the litter is thoroughly disinfected via any of the methods discussed earlier. Alternatively, a new litter may be added to the area inside the brood ring. The chicks would then have the opportunity to build up immunity to certain diseases before being exposed to the organisms in the reused litter. The use of paper over litter should also be of value in reducing exposure of broilers to pathogens and hence improves performance (Table 2).

Litter as a feed ingredient

Poultry litter normally consists of about 62% droppings, 31% bedding materials, 3% waste feed, 2% feathers and 2% foreign matter. Traditionally, these materials were used mainly as a fertiliser. In recent years, however, there have been worldwide trends for using the litter as a feed for livestock and poultry. Such trends should have a great economic impact. The inclusion of poultry litter in rations would save substantial amounts of money needed to furnish diets with expensive feed ingredients and supplements.

Ruminant animals are thought to be more responsive to feeding of poultry litter compared with other classes of livestock and poultry. This is due to the fact that about 60% of the litter protein is in a form of non-protein nitrogen (NPN) which could only be utilised by rumen microbes for synthesis of microbial protein. Recent attempts were, however, made to improve utilisation of the litter by poultry through chemical treatment, using potassium hydroxide. The treated material was included in starter rations of broiler chicks at 7.5%.

The performance of chicks on litter-containing rations was comparable with the control group of chicks receiving typical rations with conventional ingredients. Further, there were no adverse effects of the litter on meat quality, flavour, or carcass grade. Similar responses were noted with layers fed the treated litter during the first 18 weeks of age. The litter was included at 10% of the total ration and resulted in improved egg production and quality.

Single cell protein

Poultry litter may also be used in culture media for production of high quality single-cell protein. In one study, a fungi called peziza audtronica was developed in a medium containing poultry litter (30g/litre), glucose (30g/litre), vitamin B-complex (0.5g/litre) and mono-benzoic potassium phosphate (0.5g/litre). The fungi used up around 75% of the NPN present in the litter and could, thereby, produce mycelia containing around 20% protein. The mycelia protein had a high biological value and was also rich in lysine. The mycelia so produced were isolated from the litter medium and was used to replace 5% of soybean meal in broiler rations. Growth rate of chicks fed rations containing mycelia was significantly higher than that of the control group of chicks receiving soybean meal as a sole source of protein in their ration.

Other uses

The litter may be used as a fertiliser or a source of fibre on arable ploughed land where it can decompose. Moreover, the disposed litter could be used as a source of organic acids. An amount of 12 kg of organic acids could be extracted from each tonne of litter. These acids have an important value in industry, as they are used for production of detergents, disinfectants, silage additives, and many other purposes.

References are available from the author upon request

See also: Litter management – Part 1: Good litter for healthy birds


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drsalah31@hotmail.com

Dr Salah H. Esmail

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