Background: This work studied the natural infection of Neospora caninum during the first gestation of heifers in a dairy farm in animals consuming a ration Join for free Neospora caninum infection in beef cattle reared under Palabras clave: ADN, bovinos, PCR, prevalencia, seroprevalencia (Fuentes: AIMS, Anticorpos anti-Neospora caninum em bovinos, ovinos e bubalinos no Estado do Rio Principal component analysis (PCA) and Neighbor Joining tree topologies