Tension of post-vaccination immunity to causative agents of acute respiratory viral infections in calves

In the livestock enterprises of the Sverdlovsk region comprehensive programs of health measures against the pathogens of acute respiratory viral infections are developed and implemented. This allows to significantly reduce the incidence among young cattle, which are the main risk group for the development of infectious diseases of organs. A retrospective analysis of the results of serological screening of the primary postvaccinal immune response in the populations of young cattle of model agricultural enterprises in 4 districts of the Sverdlovsk region showed that in 2.2-6.8% of animals have a low level of specific antibodies to infectious agents of rhinotracheitis (TIA) Viral diarrhea (VD) and parainfluenza-3 (PG-3). An assessment was made of the risk of developing epizootics of acute respiratory viral infections in young cattle. It was established that the indicator “Waste of calves due to factor infections” in the surveyed agricultural enterprises was less than 4%. The increase or decrease in the indicator directly correlated with the results of serological screening. When the maximum number of animals with a low level of post-vaccination seroconversion was detected, the indicator “Waste of calves due to factor infections” (FI) was observed in agricultural enterprises. The maximum level of the FI indicator - 2.9% in the Beloyarsk region model farm was registered in 2015; during this period the number of calves with a low level of post-vaccination seroconversion was 11.8% of the surveyed young cattle livestock. In the model economies of the Alapaevsky region, the maximum level of the FI indicator was 3.7% in 2015; in this period the number of calves with a low level of post-vaccination seroconversion was 11.4% of the surveyed young cattle livestock. In the model farms of the Sukholozhsky and Kamensky regions, the maximum level of the FI index 2.7% and 2.8% was registered in 2016; the number of calves with a low level of post-vaccination seroconversion in this period was 9.4% and 11.1% of the surveyed young cattle livestock.