[Report of a field control experience of bovine viral diarrhea virus in 2 dairy farms of Argentina applying management, diagnostic, and vaccination tools].

Abstract

Bovine viral diarrhea virus (BVDV) causes significant economic losses in the international livestock industry and in Argentina, where it circulates at high prevalence. Under high prevalence conditions, BVDV infections are controlled through vaccination once persistently infected animals are identified and segregated. This study evaluated the feasibility of controlling BVDV circulation under field conditions by combining diagnosis, management measures, and vaccination in 2 dairy farms in the province of Santa Fe. Commercial ELISAs were used for the detection of the NS3 (P80) protein or antibodies against this protein as well as an RT-nested PCR for the detection of the viral genome, and viral seroneutralization to assess vaccine efficacy. The average seroprevalence of the farms was 58.4%, with a persistently infected animal rate of 2.4%. After segregating the persistently infected animals and vaccinating them with a commercial combined vaccine containing inactivated BVDV, abortion rates significantly decreased (p<0.05) in farm 1 (from 20.5 to 11.6%) and in farm 2 (from 34 to 23.4%) during the second year of the control strategy. Conception rates increased from 29 to 33% in farm 1 during the first year, while in farm 2, the increase was 7 points during the second year. This methodology achieved conditions in which BVDV ceased to circulate, constituting the first controlled report on BVDV management in dairy farms using tools available to producers in Argentina.