Abstract This 2-yr study was conducted to evaluate the biochemical profiles of commercial dehydrated garlic powder (DGP) and its associated influence on enteric gas fluxes, mineral intake, and body performance at a 5% inclusion level. The DGP was assessed for the stability of the bioactive compounds, especially those responsible for garlic flavor. Each year, resealed (NE) and exposed-to-air (E) DGPs were sampled serially in storage at months 0, 1, 2, and 3. Crossbred steers (n = 40 in year 1; n = 80 in year 2) were assigned to either 5%DGP or 0%DGP treatment group in a randomized complete block design, balancing for initial body weight and breed composition. Feed and supplement intakes for individual animals were monitored using an automatic feeding system. Each year, steers were fed high-grain rations in feed bunks separate from mineral supplement bunks on a free-choice basis over 72 and 82 days, respectively. Methane (CH4), carbon dioxide (CO2), oxygen (O2), and hydrogen (H2) fluxes were also measured using an automatic head-chamber emission monitoring system. Data were analyzed using a linear model in R software with year and treatment as fixed effects. Organosulfur compounds were quantified using Ultra-Performance Liquid Chromatography and Gas Chromatography. No differences (P > 0.05) were observed for allicin, allyl methyl sulfide, dimethyl trisulfide, allyl propyl disulfide, diallyl disulfide, and diallyl trisulfide concentrations in NE-DGP. In E-DGP, the greatest (P < 0.05) concentrations of allicin, diallyl sulfide, and 2-vinyl-4H-1,3-dithiin were recorded at month 1, while other compounds remained stable (P > 0.05) throughout storage months. There were no differences (P > 0.05) in dry matter intake, average daily gain, and the gain-to-feed ratio between 5%DGP and 0%DGP groups. Garlic supplementation did not also influence (P > 0.05) body composition (ribeye area, intramuscular fat, rump fat thickness, and rib fat thickness) of steers, but supplement intake was higher (P < 0.0001) in 5%DGP (204.31 gd-1) compared with 0%DGP (148.04 gd-1) group. There were no differences in the enteric fluxes from 0%DGP and 5%DGP groups for CO2 (8854.04 g·d-1, 9322.69 g·d-1; P = 0.12), CH4 (139.75 g·d-1, 154.12 g·d-1; P = 0.29), O2 (6327.84 g·d-1, 9107.30 g·d-1; P = 0.27) and H2 (0.87 g·d-1, 0. g·d-1; P = 0.17). Results suggest that organosulfur compounds in dehydrated garlic powder can be stable and contributed to enhanced mineral supplement intake of feedlot cattle but did not affect enteric gas fluxes and body performance.