To obtain a clearer insight into the oxidation-reduction reactions of blood neutrophils in bovine neonates, the kinetics of neutrophils’ chemiluminescence (CL) and viability were investigated in calves immediately after birth. In the first study, simultaneous analyses of CL kinetics and viability of neutrophils within 12 hours after birth in the calves (n = 10) were measured. In the second study, at 10 days before anticipated calving, Holstein cows were divided in two groups; they were fed diets that provided 0 (n = 6) or 50 (n = 6) gm/d of supplemental vitamin C. Within 12 hours after birth, blood samples were collected for neutrophils’ functional assays. The CL profile showed unexpectedly monophasic with very high intensity; the viability of the neutrophils was also markedly low in the neonates. Feeding vitamin C to their mother, indirectly improved viability and superoxide anion production capacity of neonatal neutrophils. Our findings suggest that the subsequent intracellular myeloperoxidase-H2O2 system is impaired, and may lead to a higher risk of infections in bovine neonates. Conversely, the slight increased viability and superoxide anion production capacity in neonatal blood neutrophils with vitamin C could lead to a better protection of neonates from infections. Further studies are in progress to explain these findings.

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