causes of wet LITTER N POULTRY

Modern commercial poultry should be given all comfort possible to help them perform above the drawn out breed standards. The day old broiler chick has an average weight of 40 grams and grows into 2 kg just in 35-36 days of age. These birds are hyperphagic, and need feed and water in ad libitumquantity.Continuous selection and breeding to improve the growth rate, feed efficiency and production have increased both the feed and water consumption. The fast growth phase is characterized by increased quantities of faecal and urinary water into the bedding material. At six weeks of age, each bird will excrete approximately half the amount of water consumed per day, into the litter on that day. Wet litter is commonly used to describe nonspecific disease of gastrointestinal or urinary tract. With disease onset, performance problems like increased feed conversion ratio, poor body weight gain, increase in marketing age, predisposition to other secondary bacterial infections and condemnation losses – start precipitating one after other.

Physiology

Water balance is equating intake and metabolic synthesis with output as urine (kidneys), faeces (gastrointestinal tract) and evaporation (skin and respiratory tract). Water intake is dependent upon the ambient temperature. Water intake is 2-2.5 times like that of feed intake. During the periods of dehydration, the thirst stimulation mechanisms are activated. Overconsumption occurs frequently because the absorption is sluggish and the cellular rehydration also takes time. Under these conditions, excess water is excreted as dilute urine to maintain water balance.Chickens have a pair of kidneys and the ureters. Urinary bladder is absent in birds. Urine excretion is unique one in birds. First ureters open into the coprodeum. Then the urine passes retrograde up the colon to the caeca before being evacuated via the cloaca with the faeces. The content of the urine is significantly altered during its passage through the coprodeum, colon and caecae. The avian kidney processes a large volume of fluid and reabsorbs most of it through tubules. In normal birds, the reasorption is greater than 95%. An increase in urinary output will cause wet litter. This is often misinterpreted as diarrhea or enteritis. Intestinal faeces are normally brown in colour with white urate cap and excreted 12-16 times in a day. Caecalfaeces are usually dark brown in colour. The ratio between intestinal and caecal droppings will be 7:1. Faecal water content is altered by the characteristics of feed ingredients. It is directly affected by increasing ingestaosmolarity or reducing transit time and absorptive surface area/ function, which compromises water absorption and stimulates intake. This results in high faecal water and is called diarrhea. Enteritis is a different one. Here gastrointestinal lining is inflamed, affects digestion and the ultimate reduction in nutrient and water absorption. This causes faecal water to increase above normal. Enteritis is usually associated with pathological conditions. Diarrhea is usually physiological in nature.

Economical impact of wet litter problems

v  Ammonia production

Poor FCR

Less body weight

v  Diseases

Morbidity, mortality, medication cost

v  Parasites

Anticoccidial drugs, dewormers

v  Carcass condemnation and downgrading

Breast blisters

CAUSES OF WET LITTER:

ü  Poor litter management

ü  Poor ventilation

ü  High temperature and humidity

ü  Overcrowding

ü  Rancid fats

ü  High level of K,Na,Cl,Ca,Mg,P

ü  Mycotoxins

ü  High level of crude proteins

ü  Poor water line management

ü  Infectious causes

Causes of enteric disorders in poultry

(a) Infectious

Disease: coccidian infections, bacterial infections caused by E.coli, Salmonella, Clostridium, Compylobacterjejuni and Spirochaetes result in wet litter. Viruses such as REO, IB, IBD, New Castle disease virus, Adenovirus, Rota virus, Astro viruses, turkey Corona viruses and Toro viruses cause diarrhea. Heavy load of internal parasites such as roundworm and tape worm infestation cause diarrhea.

(b) Non infectious

a) Feed. Structure and pellet quality, palatability, formulation and content, mycotoxins

b) Management. Available feed space, water space, distribution of feeders, drinkers, air quality, ventilation, litter, temperature and density

Infectious Causes

Avian intestinal spirochaetosis often causes diarrhea and impaired egg production both in laying hens and in breeder hens.The birds affected with Salmonella have diarrhea with pasting of feathers around the vent. The disease caused by Salmonella pullorum is known as Bacillary White Diarrhoea. Diarrhea and pasty vent are also seen in pasteurella infections.Necrotic enteritis (NE) cause by Clostridium perfringens is found worldwide. It occurs both as a clinical disease having high mortality and sub clinical disease which has a devastating effect on broiler production. NE is associated with wet litter problems and affects the production negatively. Though wet litter is due to many causes, the sub clinical necrotic enteritis is the most common infectious cause, which often goes unnoticed. Coccidiosis is a protozoan disease which causes dysentery and frequently wet litter. Coccidiosis predisposes the bird to NE and the proper differential diagnosis will help in saving the bird by treating the exact cause.In nephron-pathogenic form of infectious bronchitis virus infections, the water intake will be high and results in scouring and wet litter. Rotavirus infections cause diarrhea which is the main clinical sign. This is followed by litter eating and inflamed vent. REO (Respiratory enteric orphans) viral infections cause mucoid diarrhea with pasty vent.

Differential diagnosis

Coccidiosis

Necrotic Enteritis

Caused by protozoa by name Eimeria. More than 6 species of Eimeria in causing disease.

Caused by anaerobic, toxin producing bacteria – Clostridium perfringens.

Found in an ubiquitous manner

Found in faeces, soil, dust, contaminated feed and litter

Not a normal inhabitant of gut

Normal inhabitant of hind gut

Infection only as a result of ingestion of coccidian oocyst

Intestinal tissue damage helps in colonization by the pathogen

Causes immunosuppression

Not an immunosuppressive disease

Predisposes the bird to NE

NE is not a predisposing cause of coccidiosis

Droppings to contain raw/ coagulated blood

Droppings watery, orange colour. More liquid zone in the droppings

Gross lesions seen throughout the intestine

Gross lesions usually confined to small intestine, primarily jejunum and ileum

Hemorrhages/ raw blood in the intestine

Intestines are friable and distended with gas; Turkish towel appearance

Liver is not involved

Liver is involved

Threat of coccidiosis is less during hot dry weather and greater during cool damp weather & poor litter management

Threat of NE is throughout the year

Self-limiting disease

Not a self-limiting disease

Feed and related factors

With modern breeding and selection procedures, and the resulting high appetite and feed intake the feed passage rate is increased. This is achieved by reduced time spent by ingesta in proventriculus (glandular stomach) and gizzard (muscular stomach). But the retention time in the small intestine remains fairly constant. This reduces the enzyme –nutrient contact, leading to reduced protein digestibility and reduced feed efficiency. The passage of undigested nutrients not only has an implication on reduced digestion and absorption but also affects the gut ecology and causes wet litter. The characteristics of feed ingredients will affect the feed passage time and the water content of faeces. Nutritionally induced excessive thirst, abnormally large production of urine and diarrhea are caused by poor quality raw materials that contain high oligosaccharides or minerals. This leads to reduced surface area available for absorption of nutrients and paves the way for pathogenic infiltration and a systemic disease.

Following are the variable factors related to feed that are responsible for wet litter:

• High fiber levels of more than 7% without enzymes may cause wet droppings. These wet droppings will increase when soyabean level is high, since soyabean meal contains high level of soluble fibers. Inadequate heat treatment of soyabean meal or high levels of inclusion can lead to enteritis and wet litter.
• The feed ingredient characteristics like particle size, viscosity in solution, starch digestibility and lipid/protein/mineral content.
• Water soluble non starch polysaccharides (NSP) adversely affect digestibility by stimulating mucous production and increasing ingestal viscosity, resulting in wet litter.
• Rancid fats can compromise digestibility and can cause gastrointestinal disturbance and wet litter.
• The ingredients which are rich in high potassium can induce polydipsia, polyuria and wet litter. E.g.Soyabean and Molasses
• Feed ingredients such as wheat, barley, rye or cassava (tapioca) will often result in excessive wet droppings.
• Use of high levels of barley in the ration has been shown to increase water consumption and wet droppings.
• Nephrotoxins such as Ochratoxin, Citrinin and Oosporincan compromise renal function cause polyuria/ polydipsia and wet litter.
• High intake of minerals – Potassium, sodium, magnesium, sulphate or chloride can lead to excessive water consumption and wet droppings. Excess salt levels wet also shown to affect litter condition...
• Excess crude protein levels in the feed will increase the production of uric acid in the kidneys, lead to wet droppings. This will lead to contact dermatitis.
• Excess feed protein or poor quality feed protein not only because higher nitrogen levels, but also cause high litter moisture levels.
• Available phosphorus levels of 0.55% in the starter diet and 0.51% in the grower diet causes wet litter. The intake of excessive levels of minerals increases water requirements of broilers and contribute to wet litter problems.
• Birds that are placed on a restricted feeding programme, consume much more water than usual to feel full. As a result, the increased water intake leads to wet droppings problem. Limiting the time that water is available to broiler breeders will often help to prevent wet litter problems b y reducing the total water usage by the birds.
• Some feed additives increase the moisture in droppings. Use of sodium Aluminium silicate at 0.75% of the diet increases the droppings moisture with or without sodium correction.
• High levels of Niacin and Zinc cause gastroenteritis.
• Folic acid deficiency causes diarrhea.
• A few ionophorousanticoccidials like Lasalocid and Maduramicin cause wet litter problem. It is suggested to reduce sodium level in feed and also to adjust the chlorine level.
• Growth promoting feed additive Organoarsenicals like 3-nitro 4-hydroxy – phenylarsonic acid and 4-nitrophenylarsonic acid may cause acute or chronic toxicoses with nervous symptoms and diarrhea sometimes hemorrhagic in nature.
• Using crumbled feeds has also been shown to increase wet droppings.
• High temperature within a broiler house leads to increased water consumption and wet litter. With high humidity and high temperature, the problem can become so severe that it becomes very difficult to properly maintain the litter in a dry condition. High relative humidity at the broiler house above 70% from 18 days onwards can cause wet litter and its associated problems.
• Foggers – with low pressure systems and large particle sizes can cause wet litter if poultry house humidity is high. High pressure systems minimize residual moisture giving an extended humidity range. Foggers with fine droplet size will help avoid wet litter, which is especially important during the brooding period. Maintain a relative humidity below 70% if poor litter conditions and disease are to be avoided.
• In cold weather, when curtain openings are small, heavy outside air enters at low speed and drops immediately to the floor, which can chill the birds and create wet litter. Poultry house ventilation system and operation should be efficient enough to prevent the litter moisture content from exceeding an optimal 25%. Improving ventilation, using floor heating systems or manually turning the litter over, to ventilate can improve the wet litter.
• Water consumption increases with high stocking density. Wet liter problems occur quite easily in overcrowded houses. It is important that adequate feed and water space be provided in hot climates and additional drinkers be used during the very hot periods of the year. Correct width of the sheds especially in the open sheds plays a key role in regulating proper ventilation within the house.
• Most enteric health problems lead to higher water consumption. This increased water consumption will aggravate litter problems and ventilation and air movement through the house becomes more critical.
• Layers drink more water when they are in cages than on litter. Water consumption increases with increase in egg production. The early introduction of a high calcium layer diet in many cases causes an increase in manure moisture.

Effects of Wet litter

• Fly problems – disease transmission, nuisance
• Increase in levels of ammonia – respiratory diseases
• Breast blisters in broilers
• Pododermatitis
• Dirty eggs in layers and breeders
• Poor weight gain due to nutrient loss
• Impaired feed conversion efficiency
• Reduced livability
• Growth suppression
• Transit (transport) loss

The presence of food borne pathogens causes financial losses for the animal producer. For the modern producer, it is critical to prevent wet litter with good husbandry skills so that chickens raised in a healthy environment produce to above breed standards and create a good return for the producer in eggs or carcass weight.

Prevention and control of wet litter

Litter management

The ideal bedding material should absorb the moisture and to facilitate evaporation of moisture and gasses from the droppings. It is recommended to use fresh litter for every new batch of chicks. Sprinkle fertilizers e.g superphosphate at the rate of 5 kg / 10 m2 area before raking of litter to prevent ammonia releases.

Acidification of gut

The hind gut pH is alkaline in nature and provide more favorable environment for multiplication of Pathogens. Water and feed acidification can help in avoidance of wet litter through gut flora management.

Flushing of water lines

Water lines should be flushed periodically for removing biofilms by using descaling agents

Regular analysis of water

Higher level of TDS can cause wet litter and poor FCR, so water samples should be periodically analysed for TDS

Use of antibiotics

Judicious usage of antibiotics both in feed and water

Good ventilation

A properly laid out protocol for ventilation needs to be implemented

Regular Deworming

A regular deworming schedule should be followed to control worms

Feed analysis

Regular feed analysis should be done for detection of mycotoxins

Optimal biosecurity procedures along with the implementation of all these recommendations will help in controlling of the wet litter.

Dr. Sajid Umar Department of Pathology, University of Arid Agriculture (UAAR),Rawalpindi