PATHOLOGICAL INVESTIGATION OF INFECTIOUS BURSAL DISEASE (IBD) IN BROILER AT DINAJPUR DISTRICT

Abstract

8 broiler farms with sum of 3250 birds of various age group from four different upazila like Sadar, Birol, Birgonj and Kaharol were suspected for Infectious Bursal Disease (IBD) and studied during the period from July to December, 2012. On the basis of detail about farm history, clinical signs and postmortem investigation of infected chicks, the prevalence of IBD was 11.11%, 10.4%, 9.06% and 9.11% in Sadar, Birol, Birgonj and Kaharol upazila, respectively with an overall prevalence 10.03% at Dinajpur district. The prevalence of IBD in broiler chickens was the highest (13.13%) at 4"" week of age and the lowest (5.6%) at 6" week of age. No broiler chick was identified as positive for IBD in their first two weeks of age. The highest mortality was observed at Kaharol upazila (5.11%) and the lowest (3.2%) at Birol upazila, with total mortality rate 4.27%. The necropsy findings of infected chicks revealed haemorrhages on thigh and brest muscles; enlarged, edematous, hyperemic and haemorrhagic bursa of fabricious followed by atrophy. In some cases kidneys were found swollen. Severe lymphoid depletion and reactive cells infiltration in the interfollicular space were found in histopathological studies. Therefore, it was concluded that susceptibility of chicks to IBD is influenced by its age. Ruffled feather, depression, whitish diarrhoea with haemorrhagic muscles and inflamed, edematous, hyperemic bursa of fabricious is attributable to infectious bursal disease (IBD).