A rear-facing position and wider bays may reduce the impact of transport on horse health arising from long journeys, the findings of a study suggest.
Wider bays, in particular, seemed especially beneficial, as horses transported under such circumstances showed fewer balance-related behaviours, suggesting they found it easier to stand.
Further, horses in the study who showed more of these balance-related behaviours — particularly loss of balance — were found to have worse gastric ulceration and greater increases in muscle enzymes after transportation.
Researchers Barbara Padalino, from the University of Bologna in Italy, and Sharanne Raidal, from Charles Sturt University in Wagga Wagga, Australia, have described the findings from their transportation study in a paper published in the open-access journal Animals.
The pair noted that regulations for minimal space and direction of travel for land transport of horses varied worldwide. “There is currently no definitive guidance to promote equine health and welfare.”
They set out in their study to evaluate the effects of bay size and direction of travel (forwards or backwards) in horses by comparing behavioural, physiological, laboratory and gastroscopy parameters between transported and confined horses.
The research involved 26 mares, aged 4 to 20.
Twelve of them were confined for 12 hours overnight without feeding in an area of 148cm by 71cm so that the effects of this confinement could be assessed without the additional effects from transportation, such as motion.
All 26 mares undertook a 12-hour identical overnight road trip of 880km in Australia, in two groups of 13.
In all, 18 of them travelled in a single bay (1.9m by 76cm) and 8 travelled in a wide bay, some of which were 1.9m by 1m and some 1.9m by 1.12m. Ten of the horses were facing forward and 16 were facing backward.
Behaviour was recorded during the confinement and transportation phases of the experiment and behaviours analysed.
A clinical examination, blood samples and gastroscopy were conducted before and after the confinement and transportation segments of the experiment.
Padalino and Raider found that the frequency of behaviours relating to stress and balance increased during transport. Horses transported in a rear-facing position and in a wider bay showed fewer balance-related behaviours.
Balance behaviours, particularly loss of balance, were linked with the severity of gastric ulceration after transportation seen by gastroscopy, as well as elevated muscle enzymes.
Increased stress behaviours correlated with decreased gastrointestinal sounds.
Heart rates and rectal temperature tended to be higher among the horses that showed more balance and stress-related behaviours. They were also linked to horses with higher squamous gastric ulcer scores.
Transportation, they said, was associated with expected increases in the stress hormone cortisol and muscle enzymes, but positioning and space allowance had little effect on these.
“Findings suggest that transportation in a rear-facing position and in wider bays might reduce the impact of transport on horse health and welfare, and monitoring behaviour in transit and physiological measurements after transportation should be recommended,” they said.
Behavioural and physiological parameters were found to be more sensitive than blood, biochemical or endocrine measures in identifying horses suffering from transport stress.
The authors said the horses were very quiet during the confinement phase of the study, when no transport was involved. There were periods where horses were resting on three legs, showing a position and demeanour typical of sleep.
Some of these horses lost their balance during sleeping, which was the only occasion this behaviour was observed during confinement. After sleeping, horses typically exhibited body stretching.
“In contrast, horses during transport did not show any behaviours consistent with sleeping; they did not rest on three legs or stretch their body,” they said. Key behaviours related to balance or stress were occurring almost every 4 seconds.
The findings, they said, supported their main hypothesis that behaviours relating to stress and balance occurred more frequently in transported horses than in confined horses, and horses transported in a rear-facing position and in a wider bay size showed less balance-related behaviour.
“In particular, horses travelling in a single bay showed a higher frequency of behavioural events (both related to stress and balance) and, after the journey, demonstrated increases in cortisol, neutrophils and white blood cells that were not observed in horses travelling in wider bays.
“These observations suggest that during 12 hours’ transportation, rear-facing position and wider bays may reduce the impact of transport on horse health and welfare.”
They said that while adequate space allowance and a rear-facing positioning would appear to facilitate better balance, the effects of bay size and direction of travel on stress behaviours and long-term outcomes were less clear and require further study.
“Transportation is considered stressful because horses are confined in a small space.
“However, in our study, horses showed a different behavioural repertoire during confinement and transportation.
“Transportation was associated with increased head movements (head tossing, turning and surveying), as well as with increased touching of the tie cord, relative to behaviours observed during confinement.”
The observed head movements pointed to increased arousal — that is, anxiety, vigilance or an alert response.
The pair said the novelty of this study was the effects of space on the behaviour, health and welfare of the transported horses.
“Horses travelling in wider bays showed less balance-related movements, leaning less on the partitions and losing their balance less often, and less behaviour related to vigilance, possibly because their arousal was lower.
“Studies have demonstrated that horses experiencing loss of balance, scrambling, abrupt braking and cornering were more agitated and anxious during the journey, possibly due to fear of falling inside the trailer.
“This,” they said, “is the first study to report animal-based evidence suggesting that horses travelling in a wide bay of 1.9 square metres are better able to balance, minimising the implications of transport on behaviour, health and welfare.”
“As behaviour was more sensitive than haematology, biochemistry or plasma cortisol for assessing the emotional status of the animals in transit, video-cameras for observing the behaviour of horses during transportation are strongly recommended.”
They say further studies on horse preference for direction of travel and the effect of space and direction of travel on respiratory and gastrointestinal diseases are recommended.
Effects of Transport Conditions on Behavioural and Physiological Responses of Horses
Barbara Padalino and Sharanne Raidal
Animals 2020, 10(1), 160; https://doi.org/10.3390/ani10010160