Antioxidant Supplementation for Immunity, Growth, and Health of Dairy Calves

The neonatal period for dairy calves is critical for immune, metabolic, and physical development which opens a window of disease susceptibility. While the industry has relied on tools such as colostrum and vaccination to support early life immunity, there are several challenges when vaccinating neonatal calves; 1) the inability to mount an effect immune response, 2) interference with maternal antibodies, and 3) the imbalance of pro-oxidant production to antioxidant capacity, also known as oxidative stress (OS). Oxidative stress (OS) which is characterized as an imbalance of pro-oxidants to antioxidants, results in cellular oxidative damage and/or dysfunction. Oxidative stress has become a topic of interest in the neonatal period as it negatively impacts lymphocyte function which might affect vaccine response. Widely studied in mature cattle, antioxidant supplementation has the potential to improve redox balance and immune response. However, evidence supporting the use of antioxidants in neonatal calves is far scarcer yet necessary to optimize immunity and disease resistance. This thesis includes a review that summarizes research on the impact of antioxidant supplementation on calf immunity, health, and productivity and highlights remaining gaps in knowledge. Chapter 2 is a study in which expands upon current literature, determining the effect of parenteral antioxidant supplementation at birth on immunity, growth, and health in pre-weaning dairy calves, suggesting that parenteral antioxidant supplementation at birth can improve redox balance within the first 2 wk of life and improve intranasal vaccine response throughout the pre-weaning period. However, we did not find any differences between groups in growth performance or health status. Overall, micronutrient supplementation in pre-weaning and post-weaning calves improved immune responses but there is conflicting evidence supporting the subsequent positive impact on calf health and growth performance.