poultry diseases in iran: an epidemiological study on different causes of mortality in broilers

understanding the distributions of poultry diseases will help planning for disease control and prevention more effectively. studies on poultry diseases in iran are scarce. we investigated the incidence of mortality in broiler chicken flocks in iran as part of a national project. specifically, documents from september 2004 to november 2005 related to the mortality of broilers that were covered by the national insurance scheme were analyzed retrospectively. of the 439,188,406 broiler chickens that were covered by insurance services, 188,680,459 chickens were exposed to different diseases. the most common diseases (in descending order) were infectious bursal disease (ibd), infectious bronchitis (ib), chronic respiratory disease (crd), colibacillosis and avian influenza (ai; subtype h9n2). the mean mortality rate in broilers was 7.89%. mortality rates were higher during chicks between the third to sixth weeks of age. ai (h9n2) produced the highest mean mortality rate of 26.1%, followed by ib with a mean mortality rate of 22.1%. most of the mortalities were recorded from the southern provinces of iran. the distributions of diseases were differed in different regions which could be related to regional conditions and management parameters.