Endogenous transplacental transmission of Neospora caninum in successive generations of congenitally infected goats

•Congenital transmission in different goat families occurred over several generations.•Neospora caninum infection persisted though-out generations in goats.•Some Neospora caninum seropositive goats gave birth to a seronegative kids. Neospora caninum is a protozoan that is considered an important agent of reproductive disorders in ruminants worldwide, and vertical transmission is the main form of infection and maintenance of neosporosis in herds. In goats, there have been no studies that have evaluated the transmission of N. caninum between successive generations. Thus, the objective of this study was to evaluate, through IFAT and PCR, the endogenous transplacental transmission of N. caninum in up to five generations of six families of dairy goats naturally infected by the parasite and whether it was possible for dairy goats to become free of infection over successive generations. Ninety-five serum samples from positive animals and 75 samples from negative animals were analyzed for N. caninum. Of the 95 samples analyzed, 93 contained anti-N. caninum antibodies (97.8 %). Titers of anti-N. caninum antibodies varied (increasing or decreasing) in the offspring; however, with an increase in the number of the goat generations, the offspring tended to have lower titers (p = 0.021) at the day of birth. Reproductive disorders such as abortions, stillbirth or fetal retention occurred at a rate of 10.4 % and were not influenced by the mother's titer of anti-N. caninum antibodies at the day of parturition or abortion. The results showed that infection by N. caninum persists throughout generations in congenitally infected goats.