Dr. P.T. RAMESHM. SHIVAKUMAR2021-01-212021-01-212017-11https://krishikosh.egranth.ac.in/handle/1/5810160495This study was conducted to record the clinical signs suggestive of mycoplasmoses, changes in haematological parameters, isolation, and identification and to screen the sheep for mycoplasma antibodies. The clinical signs in the flocks which have been studied were mostly of upper respiratory tract infection like nasal discharge (74), followed by conjunctivitis (17), abortion (15), mastitis (08), arthritis (08) and corneal opacity (03) in different flocks 2with the percentage of 41.11, 9.44, 8.33, 4.44, 4.44 and 1.66, respectively. There was stastically significant elevation in the TLC in the mycoplsma suspected sheep when compared to healthy animals. Filamentous and whirl pool like structure when agitated were noticed in most of the liquid media. Three types of colonies were noticed in the present study which consisted of central nipple and granular periphery identified as Mycoplasma agalactiae, vacuolated and very big size colonies were identified as Mycoplasma ovipneumoniae and typical fried egg (nipple shaped) colonies were identified as other mycoplasma. A total of 43 isolates were tentatively identified as mycoplasma based on cultural methods and biochemical tests which comprised of 23.88%. The different species of mycoplasma as identified by biochemical tests and confirmed by PCR were M. ovipneumoniae (32), M. arginini (06), M. agalactiae (03) and M. capricolum (02) which comprised of 74.41, 13.95, 6.97 and 4.65 per cent, respectively. A total of 360 sheep were screened using Mycoplasma ovipneumoniae particulate antigen and highest seropositive animals were noticed in the lambs less than six months old (92.22%) followed by the sheep aged more than three years 65.58%. The other middle age group sheep ie, 6 month-1 year and 1-3 year had seropositivity of 28.88% and 47.77%, respectively. A significant difference was noticed in the number of ELISA positive cases in different age groups.EnglishSTUDIES ON RESPIRATORY INFECTION IN SHEEP WITH EMPHASIS ON MYCOPLASMAThesis