NEOSPORA SPECIES INFECTION IN A HERD OF DAIRY-CATTLE

Objective-To investigate the route of transmission of Neospora sp in a herd of dairy cattle in which sporadic abortions had been observed si nce the establishment of the farm in 1980. Design-Serum samples were s creened for antibodies to Neospora sp, and records from an artificial insemination program were analyzed. Animals-58 female cattle. Procedur e-An ELISA was used to screen serum samples for antibodies to Neospora sp. Fertility, calf mortality, and relationships between specific cat tle were investigated. Statistical analysis was performed on the ferti lity data. Results-Antibodies were detected in 17 of 58 (29%) tested c attle, All seropositive cattle were descendants of 2 cows purchased in 1980. Cattle that were descendants of those 2 cows were compared with their herdmates, but significant differences were not detected in the number of inseminations per confirmed pregnancy or in the number of c attle that required more than 1 insemination/pregnancy. Since 1980, th ere were 323 confirmed pregnancies in the herd, and calf mortality (pr enatal and perinatal mortality) was 24 of 323 (7%). Clinical implicati ons-Congenital transmission of Neospora organisms together with the ap parent lack of horizontal transmission observed in the herd reported h ere indicated that Neospora sp has the ability to be transmitted from dam to offspring for several generations. This mode of transmission wo uld explain the maintenance of infection in a population of cattle des pite the lack of a definitive host for the parasite.