M Bashashati - Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
Khoshkhoo Haghighi - Department of Clinical Sciences, Faculty of Veterinary Medicine, Islamic Azad University, Tehran, Iran
A Bahonar - Department of Food Hygiene and Quality Control,Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
A Kazemi - Department of Basic Sciences, Faculty of Veterinary Medicine Islamic Azad University, Science and Research Branch, Tehran, Iran

Understanding the distributions of poultry diseases will help planning for disease control and prevention more effectively. Studies on poultry diseasesin Iran are scarce. We investigated the incidence of mortality in broiler chicken flocks in Iran as part of a national project. Specifically, documentsfrom September 2004 to November 2005 related to the mortality of broilers that were covered by the national insurance scheme were analyzedretrospectively. 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 betweenthe 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 berelated to regional conditions and management parameters

Chicken; mortality; Iran; epidemiology