Respiratory diseases in calves are responsible for major economic losses in both beef and dairy production. Several viruses, such as bovine respiratory syncytial virus (BRSV), bovine herpes virus-1 (BoHV-1), bovine parainfluenza virus-3 (BPI-3V), bovine viral diarrhea virus (BVDV), and bovine adenoviruses (BAV), are detected in most clinical cases with respiratory signs. The aim of this study is to define seroprevalences of five major viral causes of bovine respiratory infections in cattle in central region of Iran (Esfahan province). The population targeted was 642 dairy cows (Holstein-Friesian) from 25 farms. Samples of blood serum from female cattle were examined. Sera were tested by commercial ELISA kits to detect antibody against BRSV, BoHV-1, BPI-3V, BVDV, and BAV-3. The results were analyzed by Chi-square test. In the present study, seroprevalences of BRSV, BoHV-1, PI3V, BVDV, and BAV-3 were 51.1%, 72%, 84.4%, 49.2%, and 55.6%, respectively. The present study shows that infections of bovine respiratory viruses are very common in cattle in Esfahan.

Species of the genus Anaplasma (Rickettsiales: Anaplasmataceae) are obligate intracellular tick borne pathogens. Three species of Anaplasma that infect cattle and sheep (A. marginale, A. centrale and A. ovis) are well recognized. Of these erythrocytic Anaplasma, A. marginale can cause diseases in the livestock with high economical losses. Species-specific PCR based on 16S rRNA gene is commonly used for detection of Anaplasma species but can not differentiate A. marginale, A. centrale and A. ovis because of sequence similarity. In this study DNA extraction was performed on 50 blood samples with presence of Anaplasma spp. in marginal point of erythrocytes in their blood smears. The extracted DNA from blood cells was analyzed by PCR and PCR-RFLP using primers derived from 16S rRNA gene and restriction endonuclease Bst1107 I. The restriction endonuclease Bst1107I only recognizes the sequence (GTATAC) in corresponding PCR product of A. marginale and cut it. The nucleotide sequence of the A. marginale 16S rRNA gene was determined and compared with the sequences of A. marginale in GenBank. The 16S rRNA of A. marginale in Iran was completely similar to the related sequence deposited in GenBank at accession number of M60313. In the present study we propose a new PCR-restriction fragment length polymorphism analysis (RFLP) method based on 16S rRNA gene for specific detection of A. marginale.

In Iran, theileriosis is normally diagnosed with traditional Giemsa staining method. This is not applicable for identification of the carrier animals. The aim of this study was to compare conventional Giemsa staining method with the PCR technique in the detection of Theileria organisms. In this study, examinations were performed on 150 blood samples from cattle without clinical signs. Sensitivity and specificity of 50 microscopic fields were compared with Theileria specific PCR. The degree of agreement between PCR and microscopic test was determined by Kappa (j) values with 95 % confidence intervals. PCR showed that 42 samples were Theileria spp. positive, while routine microscopy showed erythrocytes harboring Theileria like structures in 11 blood samples. Examination of 50 microscopic fields showed 57 % sensitivity and 99 % specificity compared to 100 % sensitivity and specificity for PCR. The j coefficient between PCR and Microscopy (50 fields) techniques indicated no level of agreement. Our results showed that the microscopic examination remains the convenient technique for day-to-day diagnosis of clinical cases in the laboratory but for the detection of carrier animal containing low parasitemia. Therefore, molecular methods such as PCR can be used as a safe method for identifying cattle persistently infected with Theileria spp.

Bovine leukemia virus (BLV), the causative agent of enzootic bovine leukosis (EBL) is an exogenous C-type oncovirus in the Retroviridae family. It causes significant economic losses associated with the costs of control and eradication programs due to carcass condemnation at slaughter and restrictions of export of cattle and semen to importing countries. The main objective of this research was to determine the seroprevalence of BLV infection in cattle herds in central region of Iran (Isfahan province) using a commercial enzyme-linked immunosorbent assay (ELISA) to detect serum antibodies against BLV. Samples of blood serum were collected from 403 female dairy cattle (Holstein-Friesian) from 21 livestock farms and 303 animals (81.9%) were BLV seropositive. A significant association was found between age as a potential risk factor and BVL seroprevalence with animals ≥ 4 years (86.6%) having a significantly (χ(2) = 35.6, p < 0.001) higher seroprevalence compared to those < 4 years (54.2%). We found no significant statistical association between seroprevalence and pregnancy, lactation status and farming systems as potential risk factors in this study (p > 0.1). It is concluded that BLV infection is a very common problem in the study area. Hence, control measures should be instituted to combat the disease and further studies are required to investigate the impact of this disease on dairy production in the country.

The aim of this study was to evaluate the blood serum and diet concentrations of copper, zinc, and iron in Holstein dairy cattle kept under semi-industrial farming in Isfahan province, central Iran. Moreover, the effects of season, pregnancy, and daily milk yield on serum Cu, Zn, and Fe concentrations were also evaluated. The study was carried out on 12 semi-industrial Holstein dairy cattle farms. A total of 120 blood serum samples (60 in each season) and 24 diet samples (12 in each season) were collected in the summer and winter. The Cu, Fe, and Zn contents were assessed in samples using atomic absorption spectrophotometer. In the summer, the mean concentrations of Cu and Fe in serum samples were lower and higher than the critical level, respectively (P < 0.05). In total diet samples, the mean concentrations of Zn were significantly higher than critical level (P < 0.05). In summer, winter, and total diet samples, the mean concentrations of Fe were significantly higher than critical level (P < 0.05). The serum Cu and Zn concentrations were significantly higher in the winter than those determined in the summer (P < 0.05). The serum Cu concentrations were significantly higher in nonpregnant than those in pregnant dairy cattle (P < 0.05). No significant difference was observed in serum Cu, Zn, and Fe concentrations of dairy cattle in different daily milk yield groups. It can be concluded that Holstein dairy cattle reared under semi-industrial dairy farming were deficient in serum Cu concentrations, especially in summer. Further, high level of Fe in blood serum might be due to feeding of cattle with diet containing excess quantity of Fe.