Seroprevalence of Bovine Herpes Virus Type 1 in the Industrial Dairy Cattle Herds in Suburb of Shiraz-iran

A cross-sectional study was made to investigate the prevalence of infectious bovine rhinotracheitis (IBR) virus using an indirect enzyme-linked immunosorbent assay (ELISA) test in a large number of industrial dairy cattle in suburb of Shiraz (Iran). Blood samples were collected from 952 dairy cows of different parities in 43 herds. None of the herds were vaccinated against IBR. The cows were divided into different groups according to herd geographical location (North, West, East and South of Shiraz city), herd size (small, medium and large), parity and production level (low, average and high yielding cows). Two hundred and thirty seven (27.68%) of cows were ELISA seropositive. However, the true BHV-1 seroprevalence was 27.93%. All of the herds were antibody positive against BHV-1. The prevalence ranged from 16.66 to 86.19% within the herds. No relationship was observed between the presence of antibodies to IBRV and the herd size. The proportion of seropositive cows increased with their parity (P<0.05), but there were no differences among the seroprevalences of BHV-1 in cows of different production groups and four geographical regions. According to the results obtained, it was concluded that the presence of latent infection in animals within the herds in suburb of Shiraz-Iran, is responsible for the presence antibody