ANTIBODIES LEVELS AGAINST Neospora caninum DURING PREGNANCY IN NATURALLY INFECTED DAIRY COWS

Abstract

Neosporosis is one of the major causes of reproductive failure in bovine around the world. The periodof gestation, in which the infection or the recrudescence of bradzoites forms occurs and reflects inthe antibodies levels, is one of the factors that define pregnancy future. Therefore, this study aimedto determine the serological profile during pregnancy of naturally infected females. To do that,serological samples of 25 Holstain Friesian cows were collected from artificial insemination dayuntil parturition, in monthly intervals. These samples were tested by indirect immunofluorescencefor IgG anti-Neospora caninum. Of the 25 animals, only 13 were used in the analysis, becausethey were seropositive since the beginning or seroconverted during pregnancy. The results showeda gradual increase in antibody levels along pregnancy, more visible at the end of the period. Weobserved a significant difference in antibodies title between initial and final periods of pregnancy, which suggests the reactivation of bradzoite forms present in tissues during pregnancy. These resultsreinforce the knowledge of antibodies fluctuation along pregnancy, affected by N. caninum reinfectionor reactivation. This serological knowledge is important to Neosporosis pathogeny, epidemiology anddiagnostic.

Keywords: bovine; indirect immunofluorescence; neosporosis; pregnancy; serology.