The study evaluated the effects of garlic, probiotics, and in combination on levels of immunoglobulin G (IgG) and growth performance in new-born Holstein calves. Thirty-two Holstein calves were randomly allocated to treatments at four days old and were maintained on them until they were 42 days old. The treatments consisted of control (C), garlic powder at 5 g/calf/day (GA), probiotics at 4 g/calf/day (PB), and the combination of garlic and probiotics (GP). Bodyweight, body length and heart girth measurements were taken to determine growth and blood was drawn to determine glucose and IgG. Faecal score and body temperature were recorded daily. Calves in GA and GP had higher IgG levels than calves in C and PB (28.0 g/L and 27.5 g/L versus 23.5 g/L and 25.5 g/L, respectively). Calves in GP and PB groups had lower faecal scores than C and GA (2.1 and 2.1 versus 2.3 and 2.2, respectively). Supplementation of GA, PB, and in combination did not affect feed intake and growth performance negatively, but improved serum IgG levels. Higher serum IgG in GP may indicate an improved intake and utilisation of nutrients that are responsible for immunity modulation and regulation. Probiotics and their combinations with garlic have the potential to reduce the incidence of diarrhoea when fed to young calves. Keywords: dairy neonates, direct-fed microbes, natural herb