[Testing the preventive properties of polyvalent inactivated vaccine (IBR, PI-3, Adenovirus 1,3) at a cattle-breeding...

Tested was an inactivated polyvalent vaccine. It was shown to produce virus-neutralizing antibodies against the respiratory viruses in high titers. The vaccine proved highly immunogenic, reactogenic, and harmless in doses of 2,3,5,7, and 10 cm3 for 30-45-day-old calves and pregnant cows in their 7th or 8th month of pregnancy. The morbidity rate among the unvaccinated calves ranged from 51 to 66 per cent, and among the vaccinated ones it was from 0 to 5 per cent on the four farms studied. The abortions caused by the IBR vicontrol was cows about 17 per cent, and with the vaccinated ones it was 1.14 per cent. Calves born by untreated control cows contracted respiratory virus infections (76 per cent), while calves from vaccinated cows did not. When there was an acute virus respiratory disease on the farms all calves were treated with a hyper-immune serum against respiratory viruses, and after recovery of the herd vaccinations and revaccinations of all calves were carried out. Discussed is the problem of the protection properties of the vaccine in the case of pregnant cows and its advantages as compared with the live vaccines in order to discontinue the transmission of live viruses onto the industrial cattle-breeding farms.