B/BW ratio for IBD diagnosis: usefulness of bursa / body weight ratio for field level diagnosis of infectious bursal disease

A detailed investigation was carried out by, making observations of bursa / body weight ratio (B/BW ratio) on 400 commercial chicken in the age group of 2-20 weeks, collected from 139 outbreaks of infectious bursal disease (IBD) in Namakkal area of Tamil Nadu. BIBW ratios observed were unique. In the IBD affected birds (5-8 weeks age group), the BIB W ratios in the acute phase was very high compared to healthy birds. The recovered birds sacrificed at 7, 10 and 14 days after outbreak were 2-2.2,1.2-1.5 and 0.7-1.1, respectively, indicating bursal atrophy.