Serum Oxidative Status and Thiol-Disulfide Homeostasis in Late-Gestation Holstein Heifers with and Without a History of Mid-Gestation Transport

İngilizce (OpenAlex)

Pregnancy in dairy cattle is characterized by marked metabolic adaptations that may influence oxidative balance. In this study, oxidative stress markers and thiol–disulfide homeostasis were evaluated in transported and non-transported Holstein heifers during the last trimester of gestation. Clinically healthy 2-year-old heifers were divided into transported pregnant (n = 21) and non-transported pregnant (n = 9) groups. Blood samples were collected from the jugular vein approximately 90 days (3 months) after the mid-gestation transport event. These samples were analyzed for total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI), malondialdehyde (MDA), native thiol (NTL), total thiol (TTL), and disulfide levels. Total oxidant status and oxidative stress index values were significantly higher in the non-transported group (p < 0.05). However, no significant differences were observed between groups in total antioxidant capacity, malondialdehyde, or thiol–disulfide parameters (p > 0.05). These findings suggest that metabolic adaptations specific to late gestation may influence systemic oxidant levels independently of transport exposure. Under the conditions of this study, transport did not induce a marked redox imbalance in pregnant Holstein heifers.