Seasonal Mineral Concentration in Diets of Esophageally Fistulated Steers on Three Range Areas

Abstract

Past analyses of Florida range plants have been hand-plucked, whole-plant samples and have been limited to a few major species sampled at a few times during the year. The objective of this study was to determine if mineral concentrations in hand-plucked samples and the boluses of esophageally fistulated steers: changed from summer to winter; changed on different range areas; could be improved by more frequent grazing. Concentration of P and K in diets collected from steers grazing pine-palmetto, transition, and pond areas were not significantly different, but Ca, Mg, and Mn were usually lower on the pond areas. Concentration of Zn was similar in diets from the 3 areas in summer, but was lower on pine-palmetto and transition areas in winter. Concentration of Fe in diets was greater on pond areas than on pine-palmetto areas, while transition areas were intermediate. Concentrations of P, K, Mg, and Mn in diets of fistulated steers declined from summer to winter. Concentrations of P, K, Fe, and Zn were not different between pastures regrazed in winter and grazed only in winter. Most hand-plucked forages declined in mineral concentration from summer to winter. Florida range must be supplemented with complete minerals regardless of season, range site grazed, or grazing management.