The present study was undertaken to determine the bacterial agents associated with respiratory tract infections in cattle and buffalo. For this purpose 100 clinically sick cattle and 100 clinically sick buffalo of both sex and age were examined. The samples were taken randomly from the Outdoor Hospital of University of Veterinary and Animal Sciences. Lahore. various District Veterinary Hospitals of Lahore and Private Veterinary Clinics of Lahore during September 2004 to February 2005.

All the animals presented during the above mentioned period were clinically examined. Those showing signs of cough and nasal discharge were clinically examined, and their respiration rate, pulse rate, temperature and lung auscultation was performed. The frequency of clinical signs were observed and found it as, abnormal lung sounds 36.5%, Nasal discharge 69%, Cough 73%, Anorexia 93.5%, Depression 90.5%, Dyspnea
28%, Fever 84.5%, Increased pulse rate 66%, Increased respiratory rate 76.5%, Increased breath sounds 64.5% and Loud breath sounds 56%.Whereas no above mentioned signs were observed in control group.

A total of 200 samples of nasal mucus were collected from 100 clinically sick cattle and l00 clinically sick buffalo. Nasal swabs were collected from clinically sick animals. Nasal swabs collected from the nasal cavity of the affected animals, in gamma sterilized cultural swabs, were properly labeled and kept at 4°C till further processing. Each affected animal was also tested For Bovine Tuberculosis using Single Intradermal Test. Smears were made from each nasal swab, stained with Gram's staining and was examined for the presence or absence of bacteria. Each positive bacterial swab was inoculated in nutrient broth, tubes, which was incubated at 37°C and then examined after
different intervals of time for turbidity. A loopful of material from positive turbid broth was streaked on the nutrient agar and incubated at 37°C for 24 hours. Different types of colonies were purified. Smears were prepared from each type of colony, stained with Gram's staining and examined under oil immersion lens. The staining and morphological characteristics were recorded. Out of total 200 samples, only 152 were positive for bacterial contamination. The prevalence so calculated was 76% amongst the animal examined. A total number of I 52 isolates belonging to the genera Pasteurella, Streptococcus. Staphylococcus. Escherichia and Mycobacteriurn were isolated and identified on the basis of morphological, staining, cultural and biochemical characters of the organisms isolated from nasal mucus of cattle and bLiffalo. Of these Pasteurella haemolytica was isolated from 43 (21 .5%), Pasteurella multocida 3 I (I 5.5%), Escherichia coli 11 (5.5%), Streptococcus 29 (14.5%), Staphylococcus 23 (11.5%) and Mycobacteriurn bovis 15 (7.5%).

The main objective of this study was to assess and record the incidence of various bovine respiratory tract infections and to study the bacterial etiological agents involved in the production of respiratory tract syndrome. The etiological agents were identified by cultural and biochemical characteristics of isolates. These findings will help in devising proper and early measures required to cure the disease and to boost LI the prodLictive performance of these ruminants.