Dhaygude, V. S.Bagal, U. R.2019-12-132019-12-132019-08-19http://krishikosh.egranth.ac.in/handle/1/5810137591The present study reports detection of M. gallisepticum and M. synoviae infections in broiler chickens by gross examination, histopathology and PCR. Incidence of pathogenic Mycoplasma spp in broiler chickens with respiratory lesions was found to be 26.66% and can be regarded as high. Out of samples from total 60 flocks, 6 flocks (10%) were found positive for M. gallisepticum and 12 (20%) were positive for M.synoviae. The incidence of M. synoviae was found to be higher than M. gallisepticum. Catarrhal tracheitis, focal pneumonic consolidation of lungs and airsacculitis were consistent lesions in M. gallisepticum and M. synoviae positive broiler chickens. However, synovitis/arthritis was not observed in any of the flock positive for M. synoviae. Incidence of E. coli amongst broiler chickens with respiratory lesions was found to be 40% and was higher than Mycoplasma spp. Mixed infections of M. gallisepticum and M. synoviae, M.gallisepticum and E. coli, M. synoviae and E. coli as well as mixed infection of M. gallisepticum, M. synoviae and E. coli were detected in 24.24% flocks out of total 33 positive flocks. Mixed infection of M. gallisepticum and E. coli was detected in 3(9.09%) flocks, M. synoviae and E. coli in 4 (12.13%), M. gallisepticum and M. synoviae in 1(3.03%) and M. gallisepticum, M. synoviae and E. coli combined infection was detected in 1 (3.03%) flock. Mixed infection of M. gallisepticum and E.coli, M.synoviae and E.coli and M.gallisepticum, M. synoviae and E.coli revealed moderate to severe lesions of chronic complicated respiratory disease.ennullThesis