Background: Trace elements are very important for several metabolic functions and their deficiency impair production and reproduction in dairy cattle. The aim of this study was to evaluate the concentrations of Cu, Zn and Fe in diet samples in Holstein dairy cattle kept under industrial and semi-industrial farming in Isfahan province, central Iran.

Materials and Methods: This study was carried out on 12 industrial and 12 semi-industrial Holstein dairy cattle farms. A total of 48 diet samples were collected. In the industrial farms, diet samples were collected from the total mixed rations (TMR) and in the semi-industrial farms, samples were separately collected from forage and concentrates. Concentrations of Cu, Zn, Fe in the cattle diet samples were determined using the atomic absorption spectrophotometry.

Results: In the industrial farms, the mean concentrations of Cu, Zn and Fe in diet samples were 13 mg/Kg, 73 mg/Kg and 494 mg/Kg, respectively and in the semi-industrial farms, mean concentrations of Cu, Zn and Fe in diet samples were 12 mg/Kg, 47 mg/Kg and 550 mg/Kg, respectively. Not only in industrial farms but also in semi-industrial farms the mean concentrations of Cu, Zn and Fe in diet samples were higher than the recommended levels by NRC in dietary dry matter.

Conclusion: Results of this study indicate that the mean concentrations of Cu, Zn and Fe in diet samples were sufficiently high and the trace elements deficiency was not seen in the diet samples of the cattle.