Vinay Ashok Kurli
Second year B.V.Sc & A.H
vinaykurlivet@gmail.com
Veterinary College (KVAFSU)
GADAG -582 101, Karnataka state
Introduction:
The poultry industry in India has sought special background for providing its own contribution to the economy of India. In tropical country like India the chief ideology kept in mind is mainly to maintain the shed in order to dissipate the heat and harmful gasses from the shed and provide best environment to the birds to bring about the best Feed Conversion Ratio (FCR) among the birds. Since years the “Cage or California system” is practised for layers and “Deep Litter system” for the Broilers.
Deep Litter system:
A chicken waste management system in which the several birds are left under a single roof and bring about mainly the droppings, along with a bedding material. These together form a litter and finally form compost. Birds are reared for 42 days at which they gain a marketable weight about 1.5-2.5 kg. The bedding material which is used is called as the poultry litter or broiler litter which is chiefly a mixture of poultry excreta, spilled food, feathers and the bedding material. The poultry litter is mainly used for raising Broilers, Turkeys, Quails, and other birds.
The common bedding materials include wood shavings, sawdust, peanut hulls, shredded sugarcane, straw, etc. The main function of the bedding material is to quickly absorb the faeces of birds and make themselves dry quickly.
Qualities of good bedding material:
1. Should quickly dry .
2. Should quickly absorb the faeces and keep the surface dry.
3. Should not be toxic to the birds and the handlers.
3. Should limit the production of ammonia.
4. Should not promote the growth of harmful pathogens.
5. It must be cheap and locally available.
6. It must be free from sharp objects and other objectionable materials.
7. Too much dried litter material causes dustiness in the farm.
8. It must be biodegradable, supply some nutrients to the birds and form a good quality manure later.
9. It must absorb moisture from droppings quickly.
10. It must be free from mould growth.
11. A good litter material is the one which breaks up when hand is open and the litter material with more moisture will form a ball in the hand.
12. Bedding materials used would show a serious and significant impact on the carcass quality and even sometimes the bird performance also because of the litter eating and poultry behaviour.
Points to be considered during adoption of deep litter system are:
1. The deep litter should always be kept dry.
2. Birds should be given right amount of space to move according to the area of shed.
3. Shed should be well ventilated.
4. The litter should be regularly stirred and if wet it should be replaced immediately by new bedding material.
5. Making convenient timing to bring up deep litter system mainly in dry seasons of the year in these times it provides good time for sufficient bacterial growth.
6. Keeping a good attention towards the water pipes and the water troughs kept in between the birds.
Litter management:
The good moisture absorbing quality of the bedding material depends on the cost and availability such as wood shavings, sawdust, peanut hulls, shredded sugarcane, straw, broken maize stalks and cobs, bark of trees, leaves and dry grasses, etc. Spread the litter material at least 5cm on the floor of pen area before introducing the chicks. And finally make the depth of the litter to about 15 cm by adding the litter material at the rate of 2 cm of bedding material per week. Such that it would make up about 10 kg of bedding material per square meter.
There should be frequent stirring of the litter which is technically called as raking. Raking should be done on intervals as at least 2 times in a week in winter season and once in a week in a hot season.
Special attention should be given on daily grading of the litter condition spread new-fresh litter on the top. It is advisable to use dry lime in order keep the litter dry at the rate 10kg per 10 m3 and rake the litter again.
• Litter will function more efficiently on an earthen floor. However a concrete floor is advised for a perfect disinfection at the end of each batch.
• Before adding fresh litter material, remove the caked up and wet litter material.
• Avoid adding of slaked lime as it increases the pH of the litter which in turn release more ammonia from the litter. This favours the growth of E. coli, the most common pathogen of poultry.
• About 3-5” of litter should be put into the house initially. Later litter material should be added till the depth of about 8-12” is reached. In winter the litter depth can be maintained up to 10-12” while in summer it may be reduced to 2.5-4”.
• In some instances, birds may bear “balls” made of litter materials at their claw tips. Ball formation is a sign of bad litter management.
Three common practices are adopted for litter management in broiler units. These include single use litter, partial re-use and multi-use litter.
• The single-use litter involves the total clean-out of the house after each flock and replacement of the bedding material, i.e., litter material is used only once.
• Partial re-use involves the removal of litter from the brooding section for spreading on the grower section of the house. New bedding material is then spread on the brooding section. The partially spent litter is often composted for a few days to elevate its temperature to kill pathogens. Some of the spent litter may be removed after each batch, and after 2 to 5 batches the house is totally cleaned out. Only caked material is removed and the house is disinfected. The litter in the brooding section is either left untouched or covered with 25 to 50 mm of fresh bedding material.
• The multi-flock litter is another practice. Which increases the incidence of pathogenic microbes and parasites.
Litter quality and performance is checked in mainly by the following levels of:
1. Moisture 2. Manure (ammonia)
The manure level is largely out of the hands of the growers however the levels of moisture can be controlled.
1. Moisture
The ideal levels of moisture in the litter material should be 24-27%
There should be continuous attention towards the heating and ventilation systems in poultry house that the moisture levels should be such that the litter material should be always friable (easily broken up) when a handful of litter is squeezed. This is known as the good thumb rule in estimating the levels of the moisture in the litter. The litter material should not be too dry and dusty which causes problems such as “dehydration of chicks, respiratory diseases, high levels of condemnations” and not be too wet also which increases the incidences of breast blisters skin burns, scabby bruising, condemnations and downgrades.
The wet litter will likely to promote the proliferation of pathogenic bacteria and even the mould and it is referred to as being caked and it would result to form the primary cause for the ammonia emission which is important environmental factor affecting the performance of the broiler production day today.
2. Manure (ammonia)
Many of the producers do not take into account about the detrimental levels of the ammonia. The human nose is able to detect the ammonia levels up to 15 parts per million (ppm) which loses the ability to sense after a long term exposure. Chicken are highly sensitive to ammonia.
Ammonia levels (ppm) Reaction
15 Sensible and can be lost after long term exposure
50-110 Burning and tear sensation of Human eye and serious health risks to workers
According to US Environmental Protection Agency the human should not be exposed to 25ppm per 8 hours (or) 35 ppm per 15 min which is considered as one of the standards. But there are some serious issues with decrease of the FCR (Feed Conversation Ratio) in broilers. Frequent exposure to ammonia causes “air sacculitis and viral infections and condemnations”.
FAVOURABLE CONDITIONS FOR THE GROWTH OF PATHOGENS IN LITTER:
1.HIGH HUMIDITY
2.HIGH TEMPERATURE
3.HIGH pH
As and when the time passes the litter become the sole source of dwelling for many pathogens. Such as Avian influenza, laryngotracheitis, gangrenous dermatitis, gumboro, reovirus, bronchitis and botulism are several with more serious viral and bacterial diseases known to spread easily.
Litter re-utilization:
Some of the producers make themselves convenient just by removing the excess cakes from the litter during the house washing and re utilising the litter for 2-3 years but do not take into account the extent of contamination of bedding material. Re-use of at least small fraction of used litter as a supplement for fresh wood shavings bedding in broiler houses has not been found significantly to increase pathogens and indicator microorganisms in litter compared to using fresh wood shavings.
A major issue with re-utilization of previously used litter is the generation of ammonia. Ammonia is produced by microbial breakdown of faecal material in the litter is the one of the important irritant to the handlers and also air polluting gas too. Some of the best ways to reduce generation of ammonia is by frequent stirring or de-caking by heating and adding litter treatments to re-used litter.
The practice of rearing broilers on built-up litter provides considerable management challenges. The potential with ammonia disease and condemnations increase each time if another flock is grown on the same litter and that intensifies the challenges of maintaining optimum in-house environment such as controlling darking-Beetles are built up houses.
The use of nipple drinkers has made it eventually possible to re-use the old litter and effectually reduce the moisture level in the built up houses
Enhancement of Litter
There is high level of re-utilisation of the litter materials has been the part of rearing the broilers in recent days and many efforts have been made towards managing the Ammonia levels generated in poultry houses.
Many amendments such as chemical and biological amendments have been developed in which the principle of these amendments is to decrease the levels of ammonia which helps in enhancement of litter quality, both in housing and as well as plant fertilizer.
Treatment products fall under 3 categories:-
1. Acidifying agents that lower the litter pH and in turn inhibit the bacterium that transforms manure nitrogen into ammonia.
2. Clay –based products that absorb odours and reduce ammonia release by absorbing moisture.
3. Products that act by inhibiting microbial growth and enzyme production through competitive exclusion and enzyme inhibition.
Currently the most effective products seem to be those that react chemically to lower the pH of litter which creates unfavourable environment for most bacteria, including those responsible for ammonia volatilisation and producers should make proper ventilation for the removal of the evaporated ammonia, failure to provide proper ventilation causes hazardous effects to birds and humans.
Most chemical treatments are effective only up to 3 weeks during brooding and have limited long term impact on ammonia concentrations especially during later stages of production. “It is extremely made clear that litter treatment is not the substitution for the good ventilation.”
The Lime which is used is chemically basic and when applied to poultry litter or the floor of a poultry house lime will raise pH and in turn facilitates the generation and release of ammonia from litter and as well as the floor soil sometimes if lime products are not recommended for the poultry house use.
So better is the use of absorbent clays which have an increased water holding capacity 5-10 times greater than lime and these clay based drying agents either with or without ammonia reducing chemical additives are excellent material to treat wet floors and spill areas.
Windrowing:
One common practice is windrow composting. This is a deep stacking of litter, usually by ploughing the litter into long rows the length of the poultry house. This is an incomplete composting process, and can eliminate harmful pathogens such as E. coli and Salmonella providing that the internal stack temperature reaches 140-160 °F .Re-spreading the stacked litter and allowing it to dry would be expected to decrease ammonia and extend litter life.
Composition of Poultry Litter :-
( From the article “Poultry manual to crops” written by M.Mohammad Amanullah TNAUC)
Micronutrient Content of Deep Litter Poultry Manure
Fe Zn Cu Mn Unit
1380 90 7.1 210 ppm
1050 430 78 530 wgg-1
842 188 55.8 268 mg kg-1
Nutrient Content Of Deep Litter Poultry Manure
Total N(%) Total P2O5(%) Total K2O (%)
2.87 1.07 1.70
3.03 2.63 1.40
1.85 1.81 –
2.05 1.95 1.20
2.80 2.30 2.30
Recycling of nutrients in deep litter system
The litter when mixed with dropping from chicken synthesizes Riboflavin (Vitamin B2) and Vitamin B12 by the chemical and bacterial actions. The built-up litter also contains niacin, phosphorus, potassium, magnesium, sodium and calcium. Deep litter bird often pecks and eats a small quantity of litter material which contains above nutrients which helps indirectly in improving the performance of birds. This phenomenon is known as recycling. Even if the poultry feed is slightly deficient in some of the nutrients, the deep litter birds will not show any deficiency symptoms due the recycling of nutrients. However, this recycling of nutrients is not possible and completely absent in cage system of rearing.
Advantages of Deep Litter System:
• Birds and eggs are safely enclosed in deep litter intensive pen, which has strong wire netting or expanded metal. Built-up deep litter also supplies some of the food requirements of the birds. They obtain “Animal Protein Factor” from deep litter.
• The level of coccidiosis and worm infestation is much lower with poultry kept on good deep litter than with birds (or chicken) in bare yards. Well managed deep litter kept in dry condition with no wet spots around waterer has a sterilising action.
• With correct conditions observed with well managed litter there is no need to clean a pen out for a whole year; the only attention is the regular stirring and adding of some material as needed.
• Generally 35 laying birds can produce in one year about 1 tonne of deep litter fertilizer. The level of nitrogen in fresh manure is about 1%, but on well built-up deep litter it may be around 3% nitrogen (nearly 20% protein). It also contains about 2% phosphorus and 2% potash. Its value is about 3 times that of cattle manure.
• It is a valuable insulating agent, the litter maintains its own constant temperature, so birds burrow into it when the air temperature is high and thereby cool themselves. Conversely, they can warm themselves in the same way when the weather is very cool.
Uses of poultry litter
1. Poultry litter is often used as an organic nutrient source in forage, cereal and fibre crop production.
2. Poultry manure, either on its own or when mixed with feed grains, has been found to be a valuable feed for cattle and fish. Poultry litter normally consists of about 62% droppings, 31% bedding materials, 3% waste feed, 2% feathers and 2% foreign matter. 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. Attempts were also 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%.
3. Poultry litter may also be used in culture media for production of high quality single-cell protein.
4. Poultry litter can be burnt directly as a fuel source to produce heat energy
5. The litter may be used as a fertiliser or a source of fibre on arable ploughed land where it can decompose.
6. The disposed litter could be used as a source of organic acids. In a study it has been found that 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.
CONCLUSION
Inadequate litter management and its utilization will lead to huge economic losses. It is a increasing concern for the poultry scientists all over the world. Selection of litter material is an important point to be considered in different agro climatic regions. However the selection of litter material depends upon cost, availability and quality. There should not be any compromise with regard to quality of litter. Many studies are being undertaken to understand the methods of proper storage conditions of poultry litter and to find the exact inclusion rate of poultry litter to plants and animals. It is also necessary to find a suitable technology of feed compounding using poultry manure and its conversion to useful bio fuel. These technologies will have huge impact on the efficient use of poultry litter.
