Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 12 4 2017 12 26 563 571 Carlos CRUZ-VÁZQUEZ Technological Institute El Llano Aguascalientes, Aguascalientes, Mexico Juan VITAL-GUTIÉRREZ Technological Institute El Llano Aguascalientes, Aguascalientes, Mexico Leticia MEDINA-ESPARZA Technological Institute El Llano Aguascalientes, Aguascalientes, Mexico Luis ORTEGA-MORA Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain Arturo VALDIVIA-FLORES Center of Agricultural Sciences, Autonomous University of Aguascalientes, Aguascalientes, México Teódulo QUEZADA-TRISTÁN Center of Agricultural Sciences, Autonomous University of Aguascalientes, Aguascalientes, México Agustín ORIHUELA-TRUJILLO Faculty of Agricultural Sciences, Autonomous University of the State of Morelos, Cuernavaca, Morelos, México 2017 12 26 2017 12 26 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 contaminated naturally with Zearalenone (ZEA), and to find out effect of mycotoxin in the levels of estrogen (E) and progesterone (P4) and that`s relation to the infection to N. caninum and in the abortions. Methods: The study was conducted in a dairy farm located in El Llano municipality, in Aguascalientes, Mexico, in 2013. Two groups were formed, the group “A” with 20 seronegative animals to N. caninum, and group “B” with 20 seropositive. Once a month was determined the levels of total IgG to N. caninum, the serum concentration of E and P4, and the level of ZEA in the ration; in cases of abortion, fetal brain samples were taken to identify the presence of N. caninum DNA. Results: In group “A”, was observed two subgroups: seronegative (60%) and seroconverted (40%), and three abortions. In group “B”, all animals maintain their serostatus, and three animals aborted. All abortions were positive for N. caninum DNA. The level of ZEA in the ration has an average of 426 µg/kg; during the gestation did not identify that animals suffer any alteration in the levels of E or P4. No statistical differences among the studied variables (levels of E and P) in time (nine months of gestation) were detected. It was not identified any interaction with the natural exposure to ZEA intake in any of the groups under study. Conclusion: The chronic ingestion of ZEA does not affect serum concentrations of E and P4 during gestation of heifers under study and cannot be related to the infection for N. caninum and the abortion. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/1930 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/1930/791