The primary objective of this study was to determine if an orally administered concentrated equine serum product provided in the first hours of life could prevent failure of passive transfer in foals. To achieve this objective, ten foals of Quarter Horse breeding were utilized. Treated foals were administered 250 ml of an oral serum product at 1 and 3 h of age via nasogastric intubation. These foals were muzzled to prevent nursing from their dam. Supplemental milk replacer (200 ml/feeding) was provided to the treated foals at 6 h and 9 h of age. Mares of treated foals had their udder stripped at 1, 3, 6, and 9 h post parturition. The initial colostrum collected (200 ml) was fed back to the treated foals when the muzzle was removed at 12 h of age. Control foals were allowed to nurse from their dams ad libitum. Jugular blood samples were obtained from all foals for determination of concentrations of plasma IgG. Plasma IgG concentrations were higher (p<.05) for treated foals compared to control foals at 5 h and 48 h of age. Plasma IgG concentrations were not different (p>.10) at all other time periods measured. All treated foals had plasma IgG concentrations over 700 mg/dl by 10 h of age, showing that the oral IgG treatment was effective in preventing failure of passive transfer in foals.