The objective of this study was to evaluate performance effects of CalfAce, a registered trademark of R&D LifeSciences LLC, compared with the antibiotic Neo-Terramycin, NT Concentrate, a registered trademark of Phibro Animal Health Corporation, and a non-treated control. Fifty-four female Holstein calves fed 0.4 to 0.9 kg of whole milk solids/day depending on age were assigned at random to 1 of 3 treatments upon birth, balanced by dam parity (n = 18). The experimental diets added to milk consisted of (1) CalfAce at 12mL/hd/d, administered 2×/d at 6mL/feeding for 21 d; (2) NT Concentrate at 46g/hd/d, administered 2×/d at 23g/feeding for 14 d; and (3) untreated control. Individual milk consumption along with grain consumption over 21 d was recorded. Serum total protein was measured 24 h post colostrum administration. Body weights were recorded at birth and the end of the experiment (d 21) to determine average daily gain. Treatment and weather conditions were recorded daily throughout the study. Data analyzed using the MIXED and FREQ procedures of SAS from calves that completed the entire duration of the study. Overall, supplementation with CalfAce led to a statistically greater number of days with 0.5 or less fecal score observed compared with control and NT Concentrate and a significantly lower number of days of treatment administration compared with control. A trend toward significance was seen for average 21-d fecal score and number of days scouring at 1.5 and 2.0 or greater in which CalfAce was the lowest. No treatment differences were observed in milk consumption, starter intake or ADG. Calf mortality due to intestinal health was equivalent between CalfAce and NT Concentrate treatments whereas control had 2 deaths.