Pasteurellosis is one of the important economic diseases in ruminants; especially in cattle and buffaloes. It is caused by Pasteurella multocida and Mannheimia haemolytica. In the current study, a total number of 128 nasal swabs were collected at winter and summer seasons from pneumonic cattle and buffaloes at different age groups from different localities. Nasal swabs were bacteriologically examined. Three P. multocida isolates and six M. haemolytica isolates were recovered from 67 pneumonic cattle with isolation rate 4.5% and 8.9 %, respectively. Also, three P. multocida isolates and six M. haemolytica isolates were recovered from 61 pneumonic buffaloes with isolation rate 4.9% and 9.8%, respectively. The isolation rate was
correlated to some epidemiological (risk) factors such as season, age and sex. In case of P. multocida the highest isolation rate was in animals belonging to (6 -12 month) followed by animals belongs to (12-24 month) age groups followed by (0 up to 6 month) age group while there is no isolation from animals belonging to (>24 month) age group; the highest seasonal
rate was in winter season and it was recorded in males. In case of M. haemolytica, the highest isolation rate was in animals belonging to (6-12 month) followed by (12-24 month) followed by (0 up to 6 month) age groups while no isolation was recorded from (>24 month) age group; the highest isolation rate was in summer season and it was observed in males.
All recovered isolates were biochemically characterized and confirmed by amplification of kmt1 gene for P. multocida isolates and rpt gene for M. haemolytica isolates using PCR technique.