DEVELOPMENT OF A DISEASE-CONTROL PROGRAM BASED ON THE USE OF AN INACTIVATED VACCINE AGAINST INFECTIOUS BOVINE-RHINOTRACHEITIS

Studies to investigate the efficacy of an inactivated vaccine against infectious bovine rhinotracheitis (IBR) suggest that this vaccine can prevent the in utero infection of calves from experimentally infected dams. In an experimental herd the inactivated vaccine induced a humora l immune response in both seropositive and seronegative cattle and, af ter subsequent intratracheal infection with IBR (BHV-1) virus, prevent ed development of symptoms in the cows and protected their fetuses aga inst infection. The calves were all healthy and were born at term, The non-vaccinated, seronegative cows responded to the experimental infec tion with mild respiratory disease and abortion of 4 out of 10 fetuses . All organs from the aborted fetuses were found to have IBR virus. Th rough the use of this vaccine, the nucleus of a seronegative, virus-fr ee breeding herd can be established. Thus, valuable genetic material c an be preserved and the eradication of IBR becomes a realistic prospec t, From our initially strictly controlled experiments producing 234 he althy calves, our programme was expanded into farm practice where 1001 calves were reared free from IBR virus.