the feed grains, macromineral sources (limestone and
dicalcium phosphate), and other exogenous contaminants from feed mixing equipment all contributed to
the greater trace mineral levels in the complete diet
mixtures. The Ca and P analyses of complete diets
were generally within 0.10% of calculated values. In
most cases, when the trace minerals from the premix
were subtracted from the total analytical values, the
indigenous contributions of trace minerals were close
to meeting the animals NRC (1998) requirement, although their bioavailability is largely unknown. The
Fe content in the final diet mixtures averaged about
150 mg/kg of complete diet above the premixes and
around 250 mg/kg greater when additional dicalcium
and limestone was used (IND + Ca:P treatment). In
the NRC treatment gestation diet, the Cu content was
about 5 mg, Mn 25 mg, Zn 38 mg, and Se 0.04 mg/kg
of diet greater than that provided by the trace mineral
premixes