Broiler colibacillosis (E. coli): symptoms, prevention and treatment records
Colibacillosis caused by pathogenic strains of Escherichia coli is one of the more common and costly bacterial diseases in broiler production. It usually strikes as a secondary infection — when flock immunity is weakened. Learn how to recognise it, how to prevent it, and how to keep treatment records.
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What is colibacillosis in broilers?
Colibacillosis is a bacterial disease caused by pathogenic strains of the coliform bacterium Escherichia coli. Some E. coli strains are part of the normal gut flora and harmless, but the group of strains pathogenic to birds (known as APEC, Avian Pathogenic E. coli) can cause severe systemic infection. In broilers the most common forms are septicaemia (blood infection), inflammation of the air sacs, and inflammation of the serous membranes: the pericardium (the membrane around the heart) and the liver capsule. More on the disease in poultry: Colibacillosis in poultry.
Why is colibacillosis usually a secondary infection?
In most cases colibacillosis is not a primary disease — it strikes only once the bird’s immunity is weakened by another factor. The way is opened by earlier viral infections (e.g. respiratory diseases), mycoplasmosis, as well as stress, poor climate, high levels of ammonia and dust in the air, and wet, dirty litter. That is why colibacillosis is called an opportunistic infection: a bacterium that would not normally harm a healthy bird attacks a flock already weakened by other problems. For this reason effective prevention focuses less on the bacterium itself and more on removing the factors that let it in.
What are the symptoms of colibacillosis in broilers?
The picture depends on the form of the disease. In septicaemia birds are lethargic, ruffled, eat and drink less, grow more slowly, and flock mortality rises. When the respiratory system is involved, respiratory signs appear: rales, coughing, laboured breathing — often as a complication of an earlier viral disease. Many changes are only visible at post-mortem of dead birds or at slaughter: fibrinous (cream-yellow) deposits on the air sacs, pericardium and liver. In chicks, inflammation of the yolk sac and navel in the first days of life is typical. Whenever mortality rises or results worsen, consult a veterinarian and arrange testing.
Why is colibacillosis so costly for the farm?
Colibacillosis hits the farm result from two sides. First, it raises mortality and worsens flock uniformity — sick birds grow worse and use more feed per kilogram of gain. Second, and often most painfully, it leads to carcass condemnations at slaughter: carcasses with inflammatory lesions in the air sacs, pericardium or liver are judged unfit for consumption at post-mortem inspection and rejected. This means the farmer can bear the cost of the bird’s whole rearing cycle yet receive no payment for it. That is why colibacillosis is one of the most common causes of economic loss in broiler production worldwide.
Colibacillosis vs. other diseases and house conditions
Colibacillosis rarely occurs on its own — most often it follows poor conditions or another disease. High levels of ammonia and dust damage the lining of the airways and make it easier for the bacterium to enter the air sacs. Wet litter, overstocking and weak ventilation increase infection pressure. So preventing colibacillosis starts with the basics of good husbandry: the right climate, biosecurity and chick quality. An overview of other broiler diseases is here: Broiler diseases, and a symptom table here: Poultry diseases — symptom table.
How colibacillosis hits the broiler flock
Each of these signals should prompt the farmer to consult a veterinarian and arrange testing.
Rising mortality and lethargy
In the septicaemic form birds are ruffled and dull, eat and drink less, and flock mortality rises — sometimes sharply when the infection adds to a viral disease.
Respiratory signs
Rales, coughing and laboured breathing appear when E. coli involves the air sacs — most often as a complication of an earlier respiratory infection or mycoplasmosis.
Airsacculitis
Fibrinous (cream-yellow) deposits on the air sacs (airsacculitis) are a classic lesion seen at post-mortem and at slaughter. It signals an infection secondary to respiratory problems.
Pericarditis and perihepatitis
E. coli causes inflammation of the serous membranes: the pericardium (around the heart) and the liver capsule, coating them with fibrinous deposit. These lesions lead to deaths and carcass rejection at slaughter.
Carcass condemnation at slaughter
Carcasses with inflammatory lesions are judged unfit for consumption at post-mortem inspection and rejected. This is a direct, measurable loss of money for the farm.
Omphalitis and yolk sac infection in chicks
In the youngest birds, infection of the navel and the unabsorbed yolk sac in the first days of life is typical — often linked to hatchery hygiene and chick quality.
How to prevent colibacillosis and how to act when disease is suspected
Effective prevention is above all good climate and biosecurity — the bacterium only attacks a weakened flock.
Good ventilation and climate
Low levels of ammonia and dust in the air protect the lining of the airways — the first line of defence against E. coli. Sound ventilation, the right temperature and humidity reduce infection pressure. House requirements: House requirements for broilers.
Dry litter
Wet, dirty litter is a habitat for bacteria and a source of ammonia. Keeping litter dry and friable (checking drinkers, ventilation and stocking density) lowers the risk of colibacillosis. Details: Poultry house litter — management.
Chick quality and hatchery hygiene
Navel and yolk sac infections originate in the hatchery and transport. Place chicks from a reliable, healthy source and ensure cleanliness and the right temperature in the first days of rearing. Basics: Broiler farming and Broiler welfare.
Farm biosecurity
Cleaning and disinfecting the house between cycles, controlling entries, rodents and wild birds, and the all-in/all-out rule reduce the number of bacteria in the environment and break the chain of infection. More: Poultry farm biosecurity.
Treatment by antibiogram
Colibacillosis is treated only with an antibiotic chosen on the basis of an antibiogram (a test of the bacteria’s sensitivity to drugs). Prudent use limits antimicrobial resistance. The drug, dose and duration are decided by a veterinarian: Veterinarian.
Treatment records and withdrawal
Every administration of an antibiotic must be recorded: date, drug, dose, route of administration and withdrawal period before slaughter. DlaFerm.pl allows these records to be kept digitally. More: Treatment records and drug withdrawal.
Frequently asked questions about colibacillosis in broilers
What is colibacillosis in broilers?add
It is a bacterial disease caused by pathogenic strains of Escherichia coli (known as APEC). In broilers it causes septicaemia, airsacculitis, and inflammation of the pericardium and liver. It leads to deaths and carcass condemnations at slaughter.
Why is colibacillosis called a secondary infection?add
Because it usually does not attack a healthy bird — it strikes once immunity is already weakened by viruses, mycoplasma, stress, ammonia, dust or wet litter. E. coli takes advantage of the situation, so prevention focuses on removing those factors, not just on the bacterium itself.
Why does colibacillosis cause carcass condemnations?add
Because it produces inflammatory lesions in the air sacs, pericardium and liver. At post-mortem inspection, carcasses with such lesions are judged unfit for consumption and rejected. The farmer then bears the cost of rearing the bird but receives no payment for it — one of the most painful losses.
How do I prevent colibacillosis in a broiler flock?add
Above all by managing the climate: good ventilation, low ammonia and dust, and dry litter. Add biosecurity, chick quality and hatchery hygiene. Good husbandry reduces the factors that let E. coli into a weakened body.
How is colibacillosis in poultry treated?add
Only with an antibiotic chosen on the basis of an antibiogram, that is a test of the bacteria’s sensitivity to drugs. Prudent antibiotic use limits antimicrobial resistance. The choice of drug, dose and duration is made by a veterinarian, and each administration must be recorded with the withdrawal period observed before slaughter.
How does DlaFerm.pl help with colibacillosis?add
DlaFerm.pl enables digital treatment and withdrawal records — legally required documentation for every administration of an antibiotic. The Flock Card lets you track mortality, weight gain and feed use, making early detection of a problem easier. Data are always available for veterinary inspections.
Keep treatment records with DlaFerm.pl
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