Transport

Physiology, Balance, and Management of Horses During Transportation

Orientation during Transit

Orientation of the horse within a transportation vehicle has been identified as a potential source of stress. Several studies have examined horses facing toward or away from the direction of travel. The advantages of facing away from the direction of travel or "backwards" includes the ease of loading a horse backwards into a trailer rather than facing a dark, small opening which may be perceived by the horse as a scary cave (Creiger,1989). Also, the hindquarters of the horse are positioned at the area of impact during braking or acceleration. In the back facing position, the horse's head is not constantly carried in an elevated position such that the horse may use its head and neck to balance more effectively. It may also be advantageous that the forelegs are placed in the rear of the trailer and may adapt to swaying motions more readily than the hind legs. This "buttress" posture adaptation is commonly exhibited during grazing, whereby the shoulder provides better lateral support than the rear legs. Often, the rear legs engage in a side stepping action when responding to lateral pressure

A study examining the response to traveling forwards or backwards during a one hour journey showed a significant decrease in heart rate in the horses traveling backwards. These horses also tended to rest more often on their rumps in maintaining their balance. The forward facing horses held their heads in a higher than average position and also moved more frequently due to difficulty in balancing. Interestingly, the forward facing horses vocalized more frequently. Heart rates increased at loading and unloading, and decreased during the journey as the horses became accustomed to the motion of transport. The authors concluded that the forward orientation may be more physically demanding due to efforts implemented to maintain balance (Waran, et al., 1996).

Heart rates were also measured in another study examining horses tethered facing forward or backward in a stock trailer undergoing road transportation for about 40 minutes compared to controls which were loaded but remained in a parked trailer for the same duration. Heart rates were not significantly different for horses facing forward or backwards during transport or while parked. However, heart rates were increased in the horses undergoing transportation. Transient increases and decreases in heart rate during transportation were attributed to the decelerations and accelerations of driving. Heart rates were highest at the start of the ride, then

decreased during the first 15 minutes, until heart rate stabilized as the horses adapted to the motion of the trailer (Smith, et al., 1994).

See http://www.vetmed.ucdavis.edu/vetext/INF-AN/INF-AN_HORSTRANSPT.HTML