A longitudinal serological follow-up of Neospora caninum natural infection in dairy goats.

Neospora caninum is a major cause of reproductive losses in ruminants, but information on antibody dynamics in naturally infected goats remains limited. This study provides the first longitudinal assessment of anti-N. caninum antibody dynamics and seroconversion during gestation, parturition, and lactation in a semi-intensive goat herd in Argentina. A total of 262 serum samples were collected from 45 goats at six physiological stages, from early gestation to 100 days of lactation, and analyzed using the indirect fluorescent antibody test (IFAT). Overall seropositivity was high (88.9%), with antibody titers showing marked temporal fluctuations across the physiological stages. Most seropositive goats exhibited low titers (100-200), while higher titers (≥400) were detected sporadically, primarily around parturition and early lactation. Individual longitudinal follow-up revealed a subgroup of goats (n = 12) with serological profiles consistent with periparturient recrudescence or reactivation, characterized by a rise in antibody titers at parturition, followed by stabilization or a decrease during lactation. Adult goats showed higher titers at parturition than younger animals, while type of parturition (single vs. multiple) was not associated with the variation in antibody levels. No abortions or reproductive disorders were observed during the study period, and negative seroconversion predominated postpartum. These findings suggest that N. caninum infection in goats is frequently subclinical and that seropositivity and transient antibody increases primarily reflect immune modulation and potential parasite reactivation. Longitudinal monitoring throughout the reproductive stages provides essential information for accurately interpreting serological results and assessing the risk of reactivation in caprine neosporosis.