Kamis, 15 Januari 2009

Yolk Sac Infection, Omphallitis

A condition seen worldwide in chickens, turkeys and ducks due to bacterial infection of the navel and yolk sac of newly hatched chicks as a result of contamination before healing of the navel. Disease occurs after an incubation period of 1-3 days. Various bacteria may be involved, especially E .coli, Staphylococci, Proteus, Pseudomonas. Morbidity is 1-10% and mortality is high in affected chicks. It is seen where there is poor breeder farm nest hygiene, use of floor eggs, inadequate hatchery hygiene or poor incubation conditions, for example poor hygiene of hatching eggs, 'bangers', and poor hygiene of setters, hatchers or chick boxes. Inadequate incubation conditions resulting in excessive water retention and slowly-healing navels and 'tags' of yolk at the navel on hatching also contribute to the problem.
• Dejection.
• Closed eyes.
• Loss of appetite.
• Diarrhoea.
• Vent pasting.
• Swollen abdomen.
Post-mortem lesions
• Enlarged yolk sac with congestion.
• Abnormal yolk sac contents (colour, consistency) that vary according to the bacteria involved.
A presumptive diagnosis is based on the age and typical lesions. Confirmation is by isolation and identification of the bacteria involved in the internal lesions. Differentiate from incubation problems resulting in weak chicks.
Antibiotics in accordance with sensitivity may be beneficial in the acute stages, however the prognosis for chicks showing obvious signs is poor; most will die before 7 days of age.
Prevention is based on a good programme of hygiene and sanitation from the nest through to the chick box (e.g. clean nests, frequent collection, sanitation of eggs, exclusion of severely soiled eggs, separate incubation of floor eggs etc. There should be routine sanitation monitoring of the hatchery. Multivitamins in the first few days may generally boost ability to fight off mild infections.



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