Keeping E coli disease at by in laying flocks

Escherichia coli (E coli) peritonitis in chicken layer flocks is one of the primary bacterial diseases for table egg farmers and remains a major issue in intensively raised commercial layers.

It is caused by a pathogenic bacterial agent called Escherichia coli. The disease-causing bacteria can get access into the chickens through the eyes, mouth, vents, cuts on the skin, or through the eggs.

Predisposing factors during the peaking period include keeping different flocks of poultry in a multi-age complex, a common practice among many poultry farmers. Exposure to other diseases like mycoplasma and/or infectious bronchitis viruses has been observed in intensively raised systems.

The disease can be made worse by housing conditions with poor ventilation and high levels of dust and/or ammonia. In young, developing birds under stress, high levels of circulating endogenous hormones will predispose these birds to peritonitis.

During the laying period, this condition is exacerbated by cases of trauma to the vents, non-lethal vent cannibalism, and/or partial prolapse of the vent. Too excessive light intensity and small-framed birds are more prone to egg yolk peritonitis.

The disease is also associated with poor feed quality, which is of prime importance. Farmers are advised to only buy feed from certified and controlled suppliers. When you mix feed yourself, use high-quality ingredients and premixes. Nutritional content, energy and protein balance, macro- and microelements, and enzymes are necessary for good development and performance.

First eggs appear at 19-20 weeks of age, and more can be expected from week 21 (141-147 days). The daily feed intake increases from 90 to 100 grams between weeks 20 and 24. During this period, an intensive, high-energy, and nutritious diet needs to be fed with increased calcium supplementation.

Calcium (Ca) and phosphorus (P) are quantitatively the most critical components of eggshells and bones and are also present in other tissues of the body. Laying birds on feed deficient in calcium and/or phosphorus are associated with this disease, especially affecting eggs before lay, a condition referred to as egg yolk peritonitis.

Both minerals are required for bone and eggshell formation. They do this by increasing the metabolism of both carbohydrates and fats in the bodies of all creatures. Interestingly, calcium and phosphorus can only function in the presence of vitamin D. So, deficiencies of the three ingredients of calcium, phosphorus, and vitamin D3 will result in soft-shell eggs in producing chickens and a drop in egg production. Vitamin C is a very important requirement of a chicken during egg production; it is naturally synthesised by the bird in the kidneys and is an anti-stress and responsible for tissue repairs.

Deficiency will result in increased layer mortality, a drop in egg production, thin and easily broken eggshells, and in birds in cages, fatigue.

The first sign of the disease is a loss of appetite and failure to eat a normal feed ratio; it is commonly seen at peak egg production.

There will be a drastic drop in egg production. The birds appear depressed, with ruffled feathers and closed eyes. This is accompanied by rapid breathing and notable watery or mucoid yellow diarrhoea. As the condition spreads, mortality will reach up to 15 per cent.

To control conditions, reduce exposure to E coli and prevent the introduction of other infectious agents in the house by improving the sanitation of the environment (housing, water, feed, and equipment). In significant operations where feed is milled on the farm, treatment of feed with products to lower bacterial levels (such as pelleting, formaldehyde, and organic acids) is most preferred.

Good housekeeping practices should be initiated, including collecting dead birds from the population more frequently and keeping low population density at 8-10 birds per m2.

Vaccinations against E coli can be done during the growing period.

Dr Messo is the company veterinarian, Kenchic; [e-mail]