Case Report: Physiological Stress Responses to Repeated, Standardized Short-Distance Transport in a Transport-Experienced Horse

Abstract

Transport is a fundamental component of equestrian training and competition. However, even horses with extensive transport experience may exhibit physiological stress responses during routine travel. This case report describes physiological stress responses in a transport-experienced 10-year-old Belgian Warmblood gelding subjected to repeated, standardized short-distance transport. The horse was transported on 17 occasions along a fixed route to a riding school for dressage training using the same vehicle, handler, and protocol to minimize environmental variability. Physiological stress markers were assessed using continuous heart rate monitoring and salivary cortisol sampling at standardized time points before, during, and after each transport and training session. Salivary cortisol concentrations increased during transport and remained slightly elevated relative to preloading reference values throughout the transport–training–return sequence. Heart rate was elevated relative to typical resting values prior to loading, peaked during training, and remained moderately elevated during subsequent transport phases. Longitudinal visualization across repeated transport events revealed a gradual decline in cortisol concentrations after approximately ten transport events, suggestive of partial physiological habituation. However, the occurrence of a physiological outlier during the fifth transport event underscores that even in experienced horses, acute stress responses can occur independently of the general habituation trend. These findings indicate that repeated short-distance transport can elicit measurable physiological stress responses in transport-experienced horses and that habituation may be incomplete despite standardized conditions and familiarity with the procedure. Taken together, these results challenge the assumption that routine transport is minimally stressful, highlighting the importance of individualized transport management, adequate recovery periods, and ongoing welfare monitoring.