ADSA Foundation Scholar Award: Shakin' off the rust-Oxidative stress and redox status as underlying factors of immune dysfunction in periparturient cows and preweaning calves.

Dairy cattle can succumb to illnesses at any given time. However, most diseases take place around 2 clusters: (1) the time around calving, commonly referred to as the periparturient period, for metabolic and infectious diseases (e.g., hyperketonemia, dyscalcemia, mastitis, metritis, and so on) and (2) the first few weeks of life, referred to as the preweaning period, for diseases of calves (e.g., diarrhea or respiratory disease). Although the pathogenesis of these diseases is different, they share the feature that animals exhibit dysfunctional immune responses. A key factor responsible for the development of immune dysfunction in transition cows and newborn calves is oxidative stress (OS), which results from the imbalance between the production of reactive oxygen and nitrogen species (ROS/RNS) during times of high metabolic demands and the availability of antioxidant defenses that are needed to reduce oxidant-induced cellular damage and subsequent loss of function. Elevated OS is linked to increased disease susceptibility, impaired immune responses, and inflammation. The field of OS has advanced considerably in recent years, and with it, we have gained a better understanding of the differences between oxidative damage and shifts in redox status, which is reflected in the information that can be obtained from different biomarkers. Antioxidant supplementation can mitigate OS, improve immune function, and reduce disease incidence. However, excessive antioxidant supplementation may lead to adverse effects. Therefore, establishing optimal supplementation guidelines based on accurate markers of oxidative damage is crucial to optimizing cow and calf health. Future research directions of redox biology in cattle are also discussed, including developing practical methods for field assessment of redox status, understanding the biological activity of oxidized macromolecules, and exploring strategies to modulate the inflammatory response. Ultimately, addressing OS during these critical periods has the potential to enhance animal health and productivity, making it a vital area of study in dairy cattle management.