Evaluation of the Field Performance of the First Commercial Neospora Vaccine in Dairy Cattle

Abstract

Neospora caninum, the causative agent of neosporosis, was recognized in 1991 as a major cause of abortion in dairy cattle in California. The first isolation of Neospora caninum from bovine aborted fetuses and experimental reproduction of neosporosis in cattle was reported in 1993. Today, neosporosis is described more commonly in dairy cattle, but also has been identified in beef breeds. Infections with Neospora, which can be acquired by cattle via congenital or horizontal transmission, have been associated with a 3-fold increase of abortion for herds with endemic abortions. For herds with epidemic abortion, the increased abortion risk can be as high as 40-fold, indicating a significant economic impact of neosporosis in affected herds. A research project was initiated to evaluate feasible control measures aimed at reduction or elimination of abortions caused by Neospora caninum.