Seroprevalance of respiratory viruses and detection of persistent BVD virus infection in beef cattle

Bovine respiratory infections are among the most important problems both in beef and dairy production worldwide. In this study, serological distribution of bovine respiratory viruses was investigated in three different age groups (6-8 month; 9-11 month; 12-15 month) of non-vaccinated beef cattle in a large capacity farm. Neutralizing antibodies specific to bovine viral diarrhoea virus (BVDV), bovine herpesvirus -1 (BHV-1), bovine parainfluenza virus -3 (PI-3) and bovine respiratory syncytial virus (BRSV) were investigated. Total of 240 blood sera samples, 80 samples from each of the age groups were collected. Seropositivity rates for BVDV, BHV-1, BRSV and PI-3 were 96.3%, 98.8%, 100%, 100% in 6-8 month of age; 88.8%, 100%, 97.5%, 98.8% in 9-11 month of age and 71.3%, 95%, 93.8%, 96.3% in 12-15 month of age, respectively. According to this study, while group of 6-8 month and 9-11 month old animals exhibited a higher seropositivity against tested agents, 12-15 month old animals were determined to have decreased ratios. In addition, it was determined that a high proportion of multiple infections on account of all tested animals were found to be seropositive at least against two and more viruses. Statistical difference was determined only between 6-8 month and 12-15 month and between 9-11 month and 12-15 month of BVDV seropositivity (P< 0.05).