STUDY OF TRACE AND ULTRATRACE ELEMENTS IN SILAGE INTENDED FOR CATTLE NUTRITION

Abstract

Grass silage and maize silage are important sources of trace and ultratrace elements in cattle nutrition. Data regarding the function, metabolism and deposition, content in feed and animal requirements, as well as some parts of risk assessment, are still needed. To study the presence of selected elements (Al, As, Ba, Be, Cd, Cr, Co, Cu, B, Fe, Pb, Li, Mn, Hg, Mo, Ni, Se, Ag, Sr, Sn, Sb, V, Tl, Ti and Zn) in silage, the appropriate analytical procedures for their determination were introduced and validated in our laboratory. After closed-vessel microwave digestion, inductively coupled plasma mass spectrometry (ICP-MS) was used to analyse samples. Grass silage and maize silage samples from three important cattle-producing regions of Slovenia were analysed and statistically evaluated. The selected elements were found in both types of silage in a wide range of concentrations, with the exception of Tl in maize silage, where all results were below the limit of detection. Statistically significant differences were found for 9 elements in grass and maize silage from three different regions and for 23 elements when comparing grass silage and maize silage. The data suggest that cattle fed Slovenian grass silage or maize silages should receive routine mineral supplementation, of which the most important trace elements needed are Cu and Se. Cattle fed Slovenian maize silage also should receive supplementary Zn and Co. Based on research in other countries, though not tested here, an I supplement is advisable too.