Effects of different positions during transport on physiological and behavioral changes of horses

Abstract

The aim of this study was to evaluate the effect of different transport positions on some physiological parameters in racehorses and their behavior patterns during and after the journey. Twelve horses made 3-hour journeys of 200 km on the same route, with the same driver, and in 3 different positions: facing forward, backward, and sideways in relation to the direction of travel. Physiological and behavioral parameters were registered before, during, and after the journey. Horses were checked at 5 different times: at rest (T0), at loading (T1), at unloading (T2), and at 2 (T3) and 4 (T4) hours after return from the journey. At each check, heart rate, respiratory rate, and rectal temperature were measured and blood samples were collected by jugular vein puncture to assess cortisol, packed cell volume, total protein, albumin, glucose, creatinine, triglycerides, cholesterol, urea, creatine kinase, lactate dehydrogenase, alanine transaminase, aspartate transaminase, alkaline phosphatase, calcium, phosphorus, and chlorine. Loading and unloading were filmed. Behavioral patterns were recorded by direct observation, during the travel, 2 and 4 hours after arrival in a new stall. The same parameters were recorded at the same times (excluding loading and unloading) in a control group that did not travel. All data were analyzed using a repeated-measures analysis (analysis of variance). Loading produced an increase of heart rate and packed cell volume in comparison with rest values. Horses facing in the direction of travel during journey made fewer forward, backward, and sideways movements than others, whereas horses traveling sideways lost their balance and touched the stall rails less frequently. Highest serum cortisol concentration value was recorded soon after unloading horses that had faced in the direction of travel (P < 0.01). Two hours after return, horses that had traveled sideways revealed an increase of creatine kinase (P < 0.01). The traveling position in the vehicle did not appear to affect postjourney behavior. In comparison with the control group, the horses that had traveled consumed concentrate faster, spent more time eating hay, and drank more frequently in the first 2 hours after return from the journey. Front-facing position led to an increase in serum cortisol concentration, whereas the sideways position caused some muscular tension, which disappeared 4 hours after the journey. Although facing backward was the travel position that provoked the greatest number of horses’ movements, it did not have a negative effect on physiological and behavioral parameters during and after the journey. We concluded that for Standardbred trotters accustomed to travel, the latter may be the less stressful position during a 200-km transport.