The effects of air transport on the behaviour and heart rate of horses

Abstract

Although many horses ( Equus caballus) travel by air, there is little information on the effect of this type of transport on their physiology and behaviour. This study monitored the behaviour and heart rate of horses during air transport to identify events that might be stressful, and to compare these measures across long and short haul air journeys. Body temperatures prior to and after transport were also measured. Heart rate was recorded before road transport to the airport to obtain resting levels, and recordings continued throughout subsequent road and air journeys. A range of social activities, together with body postures associated with balancing and resting, were recorded over a series of 30 min observation periods during the air journey. The air temperature and relative humidity (RH) in the aircraft were also recorded. During short haul flights (3–4 h), 16 horses were sampled. Heart rates were significantly higher ( P<0.05) during transitional events (i.e. while loading and unloading the truck and aircraft, and during ascent and descent) than when horses were resting or when the aircraft was in flight. In level flight, horses’ heart rates were close to resting levels and they would regularly doze and rest. In comparison, during ascent and descent, social behaviour, including aggression and submission, increased, and horses were seen to regularly change body postures to maintain balance. During long haul flights (10–15 h), 19 horses were sampled. The difference in journey length did not change how horses responded to transport events. Air temperature and humidity were highest when the plane was stationary (e.g. during loading, unloading, refuelling and delays). Although some sharp increases in heart rate and activities suggested agitation during transitional stages of air transport, these events did not appear to be frequent or long enough to be a significant welfare concern. Horses appear to adapt well to air travel under the conditions studied.