Colibacillosis: Disease that targets young birds

Young broiler chickens at the poultry farm [iStockphoto]

Many bacterial disease challenges in chickens can be complex and multifactorial. Robust feed, farm husbandry and health managements are all required to achieve good flock performances. From a young age through growing to slaughter or end of lay, chickens typically experience colibacillosis challenges that can impact negatively on producers' income. The severity of the disease will depend on the age and breed of the chicken, immune status, and level of management at reproduction farms, hatcheries, broiler farms and feed mills.

What causes colibacillosis?

The disease is caused by a bacterium scientifically known as Escherichia Coli. It is rod-shaped and is commonly isolated from the gastrointestinal tracts of animals. Most E. coli organisms are not harmful, and it is normal to find the organisms in the gut of a two-week-old chick with up to 10 million colony-forming units, without causing any infections. It is estimated that only 10-15 per cent of all E. coli organisms are harmful.

What are the signs of E. coli infections?

A drop in feed and water consumption leading to retarded growth is the first sign. You may see mucoid (slimy) diarrhoea with soiled vents and ruffled feathers, swollen heads, and moist eyes. Birds appear listless (which means lethargic, or tired) and chicks walk with an unsteady gait. Some chicks will sit in hunched position due to arthritis. There will be mortality which only declines with antibiotic treatment. Although these signs are commonly seen in any bird which is sick, in severe E. coli infections, most internal organs get infected. Other organs that get affected include the yolk sac, air sacs, heart muscles, the peritoneum, and bone endings. As soon as pathogenic E. coli bacteria are ingested or inhaled, they produce heat-stable toxins, destroying the host blood cells and leading to severe and acute septicemia. Mortality is low but has been reported to be as high as 15 per cent in compromised flocks. Financial loss occurs when birds are unable to reach market weight or peak laying percentage.

Prevention and treatment

1. Use of antibiotics

Several antibiotics are sensitive and can be used to treat this condition. Sensitivity tests must be carried out to better choose the most sensitive antibiotics. Antibiotics should only be used after prescription by a veterinarian.

2. Drinking water sanitation

Microbial contamination can be introduced from the source of water. If an effective water sanitation programme is not in place, the proliferation of bacteria will readily occur. The water should be tested always when you see a noticeable change in color, odour, or taste. A regular water sanitation and water line cleaning programme are extremely important. Chlorine is highly recommended for water sanitation.

3. Disinfection strategy

There should be a footbath at the entrance of the house for those entering the house to disinfect their footwear. To reduce the risk of rodents gaining entrance into the flock unit, clear all the vegetation in the area three to five metres around the flock house.

4. General flock house management

In poultry farms, an all-in all-out system is the best management practice as it prevents the build-up of disease-causing organisms and disease outbreaks. In cases where farmers want to keep flocks of different ages, each flock must be housed on its own with a minimum distance of 100 feet between them.

5. Feed Strategy

Source for the best quality feed in the market, poor quality feed is associated with infection of the gut leading to diarrhoea and maldigestion. Feeding space must be adjusted to avoid unnecessary overcrowding around feeders resulting in wet litter and body scratches.

6. Feed Strategy

Chickens raised on floor systems spend the rest of their lives in constant contact with litter. This litter if not properly looked after by the poultry attendant can be a source of infection. It is important to keep the litter dry and friable all the time by constantly turning it.

[The writer is Head Vet at Kenchic, [e-mail]]