A.A. Kaveh - Department of Clinical Sciences, Faculty of Veterinary Medicine, Tabriz Branch, Islamic Azad University, Tabriz, Iran
E. Merat - Graduated, Faculty of Veterinary Medicine, Tabriz Branch, Islamic Azad University, Tabriz, Iran
S. Samani - Department of Pathology, Qazvin University of Medical Sciences, Qazvin, Iran
R. Danandeh - Graduated, Faculty of Veterinary Medicine, Tabriz Branch, Islamic Azad University, Tabriz, Iran
S. Soltannezhad - Graduated, Faculty of Veterinary Medicine, Tabriz Branch, Islamic Azad University, Tabriz, Iran

Abortion in dairy cattle is generally defined as the loss of fetus on days ۴۷-۲۶۵ of pregnancy and can significantly reduce the income and capital gain of farmers and producers. Therefore, sufficient economical support and preventive measurements are essential for this issue. In this study, genetic materials were extracted from the abomasum rennet, as well as homogenous preparations of brain, kidney, spleen, liver, and lung tissues of ۱۲۸ aborted fetuses. Afterward, polymerase chain reaction (PCR) and Reverse Transcription Polymerase Chain Reaction (RT-PCR) tests were performed to identify the bovine viral diarrhea virus (BVDV), bovine herpesvirus ۱ (BHV-۱), Neospora caninum parasite, and serovars of Leptospira species. In the PCR test, the samples with ۳۸۰ bp, ۳۴۰ bp, and ۱۷۳ bp bands were considered as positive for serovars of Leptospira, Neospora caninum, and BHV-۱, respectively. Moreover, a ۲۹۰ bp band was regarded to be BVDV in the RT-PCR. According to the findings of the current study, ۳۹ (۳۰.۴۷%) of the samples were infected with Neospora caninum, ۲۶ (۲۰.۳۱%) with BVDV, ۱۷ (۱۳.۲۸%) with BHV-۱, and ۱۸ (۱۴.۰۶%) with serovars of Leptospira. In addition, multiple-agent infections were also detected in the samples. As a conclusion, the microorganism Neospora caninum was identified as the most prevalent infectious cause of abortion in the eight agro-industrial and livestock complexes, in Qazvin province, Iran.

Abortion, Bovine herpes virus, Bovine viral diarrhea virus, Leptospira, Neospora caninum, PCR, RT-PCR