Eight rumen cannulated dairy heifers (15.4 ± 0.8 mo of age and 438.31 ± 18.08 kg of BW) were fed a high forage diet with 4 different levels of starch (3.5, 12.9, 22.3, and 31.7%) and 2 types of trace minerals (TM; organic and inorganic; OTM and ITM). Inorganic TM were provided as sulfates and organic TM as proteinates (Bioplex; Alltech, Inc.). The TM analyzed were Cu, Mn, Se, and Zn. Heifers were subject to a split-plot, 4 × 4 Latin square design with 19-d periods; 15 d adaptation and 4 d sampling. The whole-plot factor was TM, and the subplot was starch concentration. Total collection of feces and urine were completed on d 15 to 19 to determine digestibility and TM excretion. Rumen contents were sampled (d 18 to 19) from 5 different locations in the rumen at 0, 1, 2, 4, 8, 12, 16, 20, and 22 h after feeding to measure pH and VFA concentrations. Plasma samples were collected to evaluate TM concentrations. Data were analyzed with the mixed procedure of SAS. Trace mineral intake was lower for OTM compared with ITM. No effect of TM on digestibility was detected, but as level of starch increased, DM digestibility increased (P = 0.08). Rumen pH was lower for diets with OTM (P = 0.01), which is consistent with higher total VFA production and butyrate proportion (P = 0.03) observed for OTM diets. These variables may be explained by the higher bioavailability of OTM and faster utilization and fermentation by rumen microorganisms. Heifers that consumed ITM had higher moisture in feces and urine excretion, which increased total manure production (P < 0.01). Excretion of TM was not different by treatment. Blood plasma was not different between treatments except for Mn that was higher for OTM. Because mineral intake was reduced and blood mineral levels were not different, these results suggest enhanced absorption of OTM compared with ITM. In conclusion, based on pH, VFA production and plasma TM concentration, OTM may be more ruminally bioavailable and absorbed in a greater extent than ITM. Also, the form of TM affects fecal moisture and urine excretion suggesting that ITM might stimulate water intake.