Infectious bovine rhinotracheitis (IBR) is a highly infectious and contagious disease that affects both the respiratory and reproductive organs. It is caused by a virus called "bovine herpes virus 1" (BHV 1). The main sources of infection are secretions from the affected organs, i.e. nasal discharge or droplets in expired air in the respiratory form, and vaginal or preputial discharges, semen and foetal tissues/fluids in the reproductive form. Transmission is therefore by air contact where animals are kept in shared housing, or at the time of mating.