A longitudinal study on the incidence of mortality of infectious diseases of commercial layer birds in Bangladesh.

摘要: Abstract A 20-month longitudinal field study was undertaken during the period from January 2010 to August 2011 determine incidence of mortality due infectious diseases affecting commercial layer birds in 8 upazilas (an administrative unit) 5 different districts Bangladesh. Diagnosis made based on flock history, age birds, clinical signs, characteristic gross and microscopic lesions, isolation identification organisms. During period, 4710 were found dead as a result disease occurrence. The rate (true rate) for 0.0171 per bird-months at risk. incidences almost all significantly higher rainy followed by summer seasons. Particularly, ND FC seasons compared winter autumn And IBD, salmonellosis, IB, colibacillosis MD than other three highest recorded below weeks aged 21 above. IBD (0.006) young ( age). Statistically no significant difference p  > 0.05) observed between groups. proportional 54.2% (including single or mixed infections). Of overall mortality, 13.4% attributed ND, 9.53% 6.69% MD, 4.33% 4.23% 3.23% FC, 3.31% colibacillosis, 1.1% aspergillosis 45.8% non-infectious causes. findings indicated that appear be major constraint