This is the most common infectious disease of poultry and is world wide in incidence.
Infection is via the oral route ,via the shell membrane,yolk/navel,water and the incubation period is 3-4 days.
Poor navel healing ,mucosal damage due to viral infections and immunosuppressive challenges are pre-disposing factors to infections.
Egg shell contamination and 14 days mortality
|Egg Condition||Total Bacteria||Coliforms||14 day Mortality|
Consequences of overheating embryos
It is not clear if overheated embryos are more sensitive because they spend longer in the hatchers(hatch early),but the% of E.Coli isolations seem to increase with :
Hours of incubation
Bigger yold sac
Treatment is by antibiotic treatment and the type of product used depends on resistance of the bacteria isolated.
Contaminated hatch debris and chick fluff in the hatchery are major sources of bacteria infection.
Prevention includes good hygiene of hatching eggs and good hygiene in the hatchery.
Good hygiene on the farm at depletion is also important because the bacteria are readily killed by disinfection.
Water hygiene is also potencially important and chlorine at 3ppm is a good option(water PH dependent PH ≤7) .
Fumigation in the hatchers with formalin has shown good results in reducing bacterial load.
|From transfer to six hours before take off||Formalin can either be applied neat concentrate (36-38%)or diluted 1:1 with water (final formalin solution of 18-19%)||60 ml of solution per m3 of hatcher space(2.03 oz per 35ft2 ),in pans with surface area of 50 cm2/m3 (7.75 in2 per 35.3 ft2).Volumes need to be adjusted for neat concentrate formalin.|