Clinical and serological observations of bovine Neospora abortion in three Dutch dairy herds
DOI:
https://doi.org/10.21423/bovine-vol1998no32.1p48-51Keywords:
abortion, calves, clinical aspects, coccidiosis, diagnosis, domestic animals, epidemiology, fertility, fetal death, fetus, infections, livestock, mummification, neosporosis, outbreaks, parasites, parasitoses, pathology, pregnancy, protozoal infections, serology, seroprevalence, stillbirthsAbstract
Three major outbreaks of Neospora abortion in 3 dairy herds in The Netherlands during 1992-1993 are reported. All outbreaks lasted 3 weeks, during the summer or early autumn, and were followed by the birth of mummified fetuses during the next 3 months. Unexpected heat in herdmates, previously diagnosed as pregnant, was also seen. There were 85 abortions in total. The length of gestation for 50 Neospora fetuses was 180ñ36 days. Within 1 year after the outbreak, 50% of the animals were culled. 49 cows were rebred. Fertility immediately after abortion was not impaired. 75 pregnancies were followed, including 21 during the second and 8 during the third year after the outbreak. 70 apparently healthy calves, including 5 sets of twins, were born. Three calves were stillborn. Three cows aborted a Neospora-infected fetus for the second time. Serial blood samples from 43 cows tested by an ELISA indicated a decrease in antibodies to Neospora to low or undetectable levels within 2 months after abortion. A rise of antibodies during the second half of gestation (following the initial outbreak) was recorded in 58% of the animals. Precolostral serum antibodies to Neospora, indicating intrauterine infection, were present in 68% of the calves tested. Seronegative cows produced seronegative calves. In all herds, seroprevalence increased after the outbreak.
