Bacteriological and serological studies on Mannheimia haemolytica infection in cattle slaughtered at Ahvaz (southwestern Iran) abattoir

Summary In order to investigate the prevalence of Mannheimia haemolytica infection in cattle, nasal and nasopharyngeal swabs and blood samples were obtained from 250 cattle after slaughter at Ahvaz (southwestern Iran) abattoir. Nasal and nasopharyngeal swabs were cultured on blood agar and incubated at 37°C for 24-48 h. The suspected bacterial cultures were processed for isolation of M. haemolytica following routine bacteriological techniques. Sera were tested by indirect hemagglutination test (IHA) to reveal antibodies against the organism. M. haemolytica was isolated from 1.6% of the sampled cattle. Statistical analysis showed that there was no relationship between age and sex with bacterial infection. Serological studies showed that 71.6% of tested sera contained antibody (titer≥1/16) against M. haemolytica. There was no association between age and sex with serological results.