Technological method for obtaining serum against parainfluenza-3, infectious rhinotracheitis, cattle viral diarrhoea

The purpose of the study is to improve the technology for obtaining hyperimmune serum against respiratory viral infections in cattle and ensure its high quality. Objectives - to optimize the scheme of hyperimmunization and exploitation of animal donors; to evaluate the effectiveness of revaccination of donors at different times after blood sampling by the titer of antibodies to the parainfluenza-3 virus (PG-3), infectious rhinotracheitis (IRT), viral diarrhea-mucosal disease (VD-MD) in cattle (cattle). For this, 4 experimental groups of donor cows with low milk production were formed. The donors were preliminarily examined for infectious diseases (tuberculosis, brucellosis, leukosis, leptospirosis), as well as for the presence of viral neutralizing antibodies to the PG-3 virus, IRT and BVD-MD. The animals in the 1st and 4th experimental groups had no antibodies to the virus PG-3, IRT and BVD-MD, and the animals in the 2nd and 3rd groups had antibodies to PG-3 virus in the dilution of 1:8-1:16, to IRT virus in the dilution of 1:4-1:8, and to BVD-MD in the dilution of 1:4. Upon completion of the initial hyperimmunization cycle, the first blood sampling followed by revaccination on the same day in the 3rd and 4th experimental groups, and in the 1st and 2nd experimental groups - 7 days after blood sampling. In the process of immunization, a pronounced immune response with the production of virus-neutralizing antibodies in titers of 1:1024 to the PG-3 virus was recorded in the 2nd and 3rd experimental groups of donors, whose revaccination was carried out on the day of blood sampling. In animals of the 1st and 4th experimental groups, the maximum increase in specific antibodies at a dilution of 1:512 was established.