Evaluation of Redox Status, Energy Metabolites, and Immune-inflammatory Status in Dairy Cows at the Close-up Stage

The aim of this study was to elucidate current perspectives of redox status in dairy cows and their effects on energy metabolites and immune-inflammatory status during the close-up period. The study was conducted on dairy cows at various stages of lactation, between November 2019 and January 2020. An observational study was conducted on 36 cows, at ~ 4 weeks (28 day ± 2 day; means ± SD) before the expected time of calving. Cows were proved healthy on both clinical and laboratory examinations. A blood sample was drawn from each cow on the 28th day before the expected time of calving to quantify selected biochemical variables. The study cows were allocated into two groups based on serum oxidative stress index (OSi) concentrations, the first group included twenty-seven cows with high values of OSi, while the second group included nine cows with low values of OSi and served as negative controls. All cows were clinically healthy and showed no signs of illness throughout the study period. Cows with high OSi had higher serum levels of advanced oxidation protein products, reactive oxygen species (ROS), malondialdehyde, superoxide dismutase, non-esterified fatty acids, β-hydroxy butyric acid, glucose, serum amyloid A, haptoglobin, and immunoglobulin G than negative controls; while had low levels of serum anti-oxidant capacity (SAC), glutathione peroxidase, vitamin E, and insulin. The results herein confirmed that cows during the close-up period were likely under oxidative stress, and the latter makes cows vulnerable to the development of negative energy balance and significant immune-metabolic alterations. The results of OSi, ROS, and SAC could be used as reference variables to assess the redox status of transition dairy cattle.