The role of colostral immunity in the effectiveness of serological detection of BLV

Abstract

The purpose of our research was to study the influence of newborn calves colostral antibodies on the efficiency of bovine leukemia virus detection by serological methods. The research was conducted on the basis of agricultural organizations within the territory of the Ural Federal District (Chelyabinsk region). We undertook comprehensive diagnostic studies of calves fed with milk from seropositive and seronegative animals using polymerase chain reaction, ELISA test, and immunodiffusion test. Experimentally it was found that feeding calves with milk from seropositive and seronegative cows led to colostral immunoglobulins persistence for up to 3-3.5 months, in most of the animals, which may be associated with the end of suckling period in calves. At the same time, serological screening of animals during this period is difficult due to the influence of a high concentration of colostral antibodies. The obtained results of laboratory studies indicate the efficiency of PCR diagnostics in detecting a specific locus of the calf leukemia virus in animals at the early stages of the infectious process. PCR diagnostics provides an opportunity to early evaluation of calves with a latent course of BLV, excluding the influence of colostral immunity, thereby reducing the recovery time of enterprises from the leukemia virus by 20%.