Whole amaranth plants from five amaranth accessions were analyzed for Ca, Cu, Fe, Mg, Mn, P, and Zn content. The accessions analyzed were AVRDC No. 86,A. caudatusL., “Edulis” morphological group; RRC 434,A. cruentusL., “Mexican” morphological group; R155,A. cruentusL., “Mexican” morphological group; UNZA‐A2,A. hypochondriacusL., “Aztec” morphological group; and R 103,A. tricolorL., “Vegetable” morphological group. Results indicate that the mineral content of amaranth is above the levels recommended for cattle. Chemical analysis of grain amaranth plants of accession RRC 434 harvested at 45, 60, and 75 days after planting showed that mineral content is relatively stable with advancing plant age. Significant reduction in leaf protein content was recorded at 75 days. There was no significant difference in daily dry matter intake, milk protein, milk solid‐not‐fat, and milk production when dairy cows were fed with 37% of amaranth crop residues in roughage.