Relations between macro and trace elements in the serum of dairy cows in Urmia, Iran

Serum concentrations of the major nutritive elements, Mn, Mo, Cu, Fe, Mg, Ca, Na, K, P and Cl, and their interrelationships were evaluated in 20 dairy herds in Urmia, northwest of Iran. Values were determined by atomic absorption, auto analyzer spectrophotometry and flame photometer. Mean Mn, Mo, Ca, P and K were less and Fe and Cu were higher than the reference values. Herd effects were present for the majority of elements, but not K, Na, Fe and Cl. The strongest correlations were positive between Cu/Mo and Ca/Mn, with weaker but significant positive correlations between Mn/Ca, Mo/Cu, Fe/K and Fe/Cl. Negative correlations existed between Ca/K, Ca/Mo, Mg/Mo, Mg/Mn, Mg/P, Fe/Mn, and Fe/Mo. Correlations coefficients with Mo and to a lesser extent Mn were higher than for other elements. There were two principle components in the dataset, explaining 12 and 11% of the variation respectively, involving mainly Fe and Mo in the first component and Ca and Mo in the second. It is concluded that Fe, Mo, Mn and Ca concentrations in the serum of dairy cows in this region were of particular importance in explaining variation in the element concentrations in serum of cows in Urmia, Iran.