Influence of short‐ and medium‐distance road transport on oxidative stress in horses

Summary Background Transport is a routine stressor in equine management, yet the oxidative impact of short‐ and medium‐distance journeys remains poorly characterised. Objectives To investigate the effects of 50 km and 300 km road transport on oxidative stress biomarkers in horses. Study Design Longitudinal experimental study with repeated measures. Methods Eleven healthy Quarter Horses underwent two journeys (50 km and 300 km). Serum samples were collected at nine time points: before transport (T0), immediately after (T1) and up to 144 h post‐transport (T2–T8). Biomarkers evaluated included nitric oxide (NO), ferric reducing antioxidant power (FRAP), superoxide dismutase (SOD) and malondialdehyde (MDA). Results Medium‐distance transport (300 km) induced significant oxidative alterations ( p < 0.001), characterised by a marked decrease in SOD activity and an increase in MDA concentrations from T1 to T6. In contrast, the 50 km journey resulted in only mild, inconsistent changes. NO and FRAP showed high variability and no significant differences between distances. Main Limitations Limitations include the relatively small sample size ( n = 11) and the lack of climate control during transport, leading to variable environmental temperatures throughout the journey. Conclusions Transport over 300 km triggers a substantial oxidative imbalance and cellular damage that persists during the recovery phase. Potential Relevance Horses transported over medium distances may require at least 48 h of rest and potentially antioxidant supplementation to restore redox homeostasis before returning to high‐intensity exercise.