¹Kafkas University, Faculty of Veterinary Medicine, Department of Internal Medicine, TR-36100 Kars - TÜRKİYE
²Kafkas University, Faculty of Veterinary Medicine, Department of Physiology, TR-36100 Kars - TÜRKİYE
³Kafkas University, Faculty of Veterinary Medicine, Department of Obstetrics and Gynecology, TR-36100 Kars - TÜRKİYE DOI : 10.9775/kvfd.2026.36861 This study included 20 Simmental calves (7-15 days old) presented with diarrhea and 10 healthy age- and breed-matched controls. Following clinical examination, mental status, dehydration score, respiratory rate, heart rate, and rectal temperature were recorded. Fecal samples were collected from diarrheic calves meeting sepsis criteria; calves positive for both rotavirus and coronavirus on a rapid immunochromatographic test were enrolled. The calves were hospitalized, treated, and monitored for 3 days. Blood samples were collected and clinical examinations were repeated before treatment (0 h) and during treatment (12, 24, 48, and 72 h). In septic calves, serum levels of reduced glutathione (GSH), total thiol (TT), native thiol (NT), endothelin-1 (ET-1), free triiodothyronine (fT3), free thyroxine (fT4), and insulin-like growth factor-1 (IGF-1), which were low before treatment, increased during therapy. Conversely, respiratory and heart rates and the levels of malondialdehyde (MDA), disulfide, and cortisol, which were high before treatment, decreased during therapy. Based on history, septic calves were further categorized as colostrum-fed or non-colostrum-fed, and group effects, time effects, and group x time interactions were evaluated. Among the evaluated parameters, MDA, IGF-1, and IgG showed the most pronounced group- and time-related differences. In conclusion, assessment of serum GSH, TT, NT, ET-1, fT3, fT4, IGF-1, MDA, disulfide, and cortisol (reflecting oxidative stress, endocrine response, and thiol-disulfide homeostasis) may contribute to the characterization and monitoring of systemic inflammatory, oxidative, endocrine, and immune alterations in neonatal calves with rotavirus-coronavirus coinfection-associated diarrhea and sepsis. Keywords : Calf, Hormones, Immunoglobulin G (Ig-G), Neonatal period, Sepsis, Thiol-disulfide homeostasis