Two-horse straight-load horse trailers appear to be associated with a higher risk of transport-related injuries compared with trucks and gooseneck rigs, Australian researchers report.
“This could be related with the reduced stability that trailers have compared with the other vehicles,” Barbara Padalino and her colleagues reported in a study that explored horse transport management practices associated with injuries and health problems in Australia.
“The elevated risk of injury in straight trailers compared with those in which horses are situated at an angle (about 45 degrees) was an interesting finding and reflects recommendations made previously that discourage placing horses so that they are facing in the direction of travel,” the researchers wrote in the open-access peer-reviewed journal PLOS ONE.
“Horses tend to lose their balance more easily when facing the direction of travel, in particular at abrupt stops.
“Their posture when facing in this direction also tends to be more rigid and less relaxed, potentially making them more susceptible to injuries,” they said, citing earlier research.
The study team noted that the transport vehicle and its internal design had been previously linked to injuries during animal transportation.
“Taking into account that most of the currently used methods and practices for the transportation of horses have been established over a period of time by the demands of the industry, with few governmental or industry standards applicable, our findings support the need for a stricter application of standards in horse transport vehicle design.”
The researchers from the University of Sydney and Charles Sturt University conducted an online survey in 2015 for their study . The survey sought demographic information about each respondent, the transport management strategies they used before, during and after transportation, and transport diseases experienced in the previous two-year period.
They analysed the results to find associations between respondents’ details, their transport strategies, and transport-related health issues, specifically traumatic injuries, diarrhoea, heat stroke, muscular problems, laminitis, transport pneumonia and colic.
The survey generated 797 useable responses.
Traumatic injuries, such as lacerations and contusions, were the most common transport-related problem, with a reported incidence of 45%.
Younger respondents – those aged under 40 – caring for large numbers of horses (more than 30 in a week) were more likely to report transport-related injuries.
Injury risk was also linked to the use of protections and tranquilizers before transport, and checking horses after the journey.
Diarrhoea (20.0%) and heat stroke (10.5%) were reported more by amateur than professional horse carers.
Increased risk of heat stroke was linked to the restriction of hay and water before transportation.
Muscular problems (13.0%) appeared to be exacerbated when horse health was not assessed before the journey; whilst the risk of laminitis (2.9%) was around three times greater when post-transport recovery strategies were not applied.
Associations were also made between transport pneumonia (9.2%) and the duration of journey, and with activity – horses involved in racing were at greater risk.
The researchers found no associations between the incidence of colic (10.3%) and the variables examined.
The study team said the findings should be interpreted with caution as they represented participant perceptions and recall.
“Nevertheless, results support many current recommendations for safe transportation of horses. They also highlight the need to further investigate many of identified management factors to refine existing policies and practices in equine transportation,” they said.
Discussing their findings, the researchers noted that horses managed by respondents younger than 40 appeared to be at greater risk of transport-related injuries than those managed by older respondents.
“These findings support the assertions commonly found in the literature that horses should be managed during loading and travelling by experienced and educated people.
“Our finding may be linked not only with limited experience in horse handling but also in driving skills. Driving ability has been identified as a factor associated with transport-related injuries, due to erratic driving related to lack of experience, impairing the horse’s ability to balance in the trailer.”
Similarly in cattle, drivers with less than 5 years’ experience reported a higher incidence of injuries associated with transportation, they noted.
The study team said traumatic injuries during transportation may also involve horse handlers.
“An elevated risk of injury has been associated with poor experience, misjudging how to handle a situation, reduced attention caused by distraction, taking a general view, and failing to consider other strategies that may reduce risks.
“To improve safety for humans and horses, knowledge and experience in horse handling and driving would appear important.
“The odds of a horse injury associated with transport was four times greater for respondents who took care of more than 30 horses.
“This may be related to the fact that moving larger numbers of horses increases the likelihood of traumatic injuries, supporting the assertion that injuries during transport happen mainly by accident.
“The higher likelihood of injuries associated with the use of tranquilizers may be related with the fact that tranquilizers can affect the horse’s proprioception and balance, increasing the risk of falling over at loading and during travelling.
“The results of this study therefore support studies and recommendations that advocate no use of tranquilizers prior to and during journeys.”
A higher risk of injuries was also associated with the use of protection. “Although this finding seems counter-intuitive, the use of leg protections and head bumper guards has previously been discouraged during transportation of horses.
“Protections should be used only on horses completely accustomed to them, they should be properly applied and checked periodically en route, and they should not worn for a long period of time. That is, the use of protective equipment should probably be limited and not universally recommended.”
The researchers said the link identified in the study between elevated risk of diarrhoea and the amateur status of the respondents was interesting.
“Diarrhoea may be a response to an acute stress and equitation science theory suggests that when pressure on the horse is not released correctly, horses tend to be more agitated and show more conflicting behaviours.
“Thus, horses managed during transportation by less experienced people may be under more stress and consequently experience diarrhoea more frequently.
“This hypothesis would need to be investigated in more detail through prospective observational studies comparing handling and management procedures of amateurs and professionals on such potential physiological stress responses, as diarrhoea.”
Horses transported by amateur respondents were also more likely to experience transport-related heat stroke in their horses. “This may have also been due to greater emotional stress when horses were not managed correctly. Agitated horses have been reported to suffer heat stroke even when weather conditions are said to be comfortable.
“The risk of transport-related heat stroke was higher when water and hay were restricted before transport. Dehydration can impair equine thermoregulation and lead to heat stroke.”
Offering free access to water and hay before a journey can act to ensure good electrolyte balance and hydration status, enabling horses to better handle environmental conditions and stresses that could result in significant dehydration and electrolyte losses during transportation.
“Due to Australia’s climate, horses can at times be transported in extreme heat and high humidity. Therefore ensuring horses are properly hydrated seems a ‘common sense’ strategy to enhance their wellbeing during travel. Therefore, hay and water restrictions prior to transport should be avoided.”
The researchers found the risk of laminitis associated with transport was significantly elevated when there was a lack of a post-transport recovery strategy, such as rehydration and walking.
“There is a lack of research testing the effects of specific recovery strategies on the risk of transport-related diseases, however rehydration, hand walking and housing in paddocks have been recommended.”
Even though transport-related colic was reported by more than 10% of the respondents, no associations were found with the variables investigated in the study.
Transport has been identified as a risk factor for simple colonic obstruction and distension colic, along with increased concentrate intake, a change in feeding and medical treatment.
“We can therefore speculate that transportation may worsen gastrointestinal conditions and contribute to colic development, in particular in association with poor watering and inappropriate diet management
“However, more research is required to identify other unknown risk factors in transport-related colic.”
The study team said their findings needed to be interpreted with caution, given that transport-related problems obviously involved a range of factors and their research involved only a survey.
“The factors identified in this study warrant future experimental exploration in order to test the efficacy of some strategies and generate more concrete guidelines to safeguard the transported equine.”
Padalino was joined in the study by Evelyn Hall, Peter Knight, Pietro Celi, Leo Jeffcott and Gary Muscatello, all affiliated with the University of Sydney; and Sharanne Raidal, from Charles Sturt University in Wagga Wagga, New South Wales.
Padalino B, Raidal SL, Hall E, Knight P, Celi P, Jeffcott L, et al. (2016) A Survey on Transport Management Practices Associated with Injuries and Health Problems in Horses. PLoS ONE 11(9): e0162371. doi:10.1371/journal.pone.0162371