Mineral Dynamics in Beef Cattle Diets from a Southern Mixed-Grass Prairie
Journal of range management
Acute and chronic dietary detldencies in macro and micro minerals have signific8nt imp8cts on production efficiency on rangelands throughout the world. However, limited information is available on the mineral quality of diets prim&y because srlivary and soil mineral contamination of eaopbrgeal extrusa precludes quantitative recovery of dietary minerals. Mineral profile# of diets can be estimated indirectly, however, ifforage species composition of diets and mineral concentrations of selected
... ions of selected forages are known. The objective of this study was to utilize this approach to estimate seasonal dynamics of phosphorus (P), caldum (Ca), potassium (K), and magnesium (Mg) in cattle diets' relative requirements. Two diet selection scenarios were developed: the first, maximum mineral intake, assumed &tie consumed only live plant tissue of a forage ifit was available; the second, considered minimum mineral intake, assumed cattle consumed live and dead tissue in direct proportion to their availability. Calculated concentrations of P and Ca in diets showed P concentrations were below and Ca concentrations were above their respective requirements for spring calving cows regardless of selection scenario or season of the year. However, K and Mg concentrations varied as a function of selection scenario and season of year and ranged from adequate during periods of rapid vegetation growth to marginally inadquate during periods of water (drought) or temperature (winter) induced donnancy.