[Detection of antibodies against Neospora caninum in cows on Hessian farms with abortion and fertility problems].

To address the question whether N. caninum-infections occur in German cattle, 388 sera from dairy farms with abortions and fecundity problems in North Hesse were tested for antibodies to N. caninum and seropositive farms epidemiologically analyzed. 16 sera (4.1%) with titres of > or= 1:400 from a total of 10 farms (45.5% of the farms) were considered Neospora-positive. There was a conspicuous clustering of seropositive and indifferent animals in three farms. A history of abortion could not be established for all seropositive cows, a finding which may indicate that some animals mount an immune response that can protect against abortions. The validity of the indirect immunofluorescent assay for the diagnosis of the Neospora caninum-infection of cattle is discussed.