This study looks at the variation in immune response (IR) of pigs in different litters and individual pigs. This variation may influence the IR to infectious disease and allergens as well as to vaccination. Intervention may have the potential to favorably alter immune response capability in newborn piglets which can induce lifetime benefit in general health. This study attempts to find out if controlled prophylactic exposure of neonates to safe microbial stimuli in the form of injected heat-killed bacteria will balance the immune system response. Heat-killed E.coli or bacterial derivatives lipopolysacharide (LPS) or muramyl dipeptide (MDP) were given by intramuscular injection (im) on each of days 1-7 of life or the live probiotic Lactococcus lactis (LL) was given orally on days 1-7, 10, 12, 14, 21, 28 & 35. Pigs were then given the egg allergen ovomucoid (Ovm) to trigger the immune system. Treatment with LPS significantly reduced frequency of allergic signs while MDP increased frequency. Neither treatment altered severity of signs. There was no significant effect of E.coli treatment on frequency or severity of clinical signs of allergy. The results confirmed that all the treatments can modulate IR in newborn pigs. Treatment of newborns with LL was able to significantly induce a type 1 immune response.