Transport-related Pneumonia. It is well-known transporting horses carries a significant risk – not just of injury, but also disease, such as colic and respiratory problems. Studies have shown transport is stressful, but does the level of stress experienced by the individual horse predict the development of health-related diseases, like pneumonia?
As an equine veterinarian, rider, driver and Standardbred breeder, Dr Barbara Padalino has first-hand experience and a special interest in transport-related problems. She began researching on this topic in 2011 and completed a PhD on horse transportation with the Faculty of Veterinary Science at the University of Sydney last year. Today, her work in this field is ongoing.
During the course of her research, Dr Padalino has been interested in understanding why, during the same journey, some horses develop respiratory illness, while others don’t. “If we could predict which horses are more likely to become affected,” Dr Padalino says, “we could provide timely, veterinary intervention to minimise the progression of the disease after the journey.”
(Check out Dr Padalino’s tips for safe transport at the end of this article)
Dr Padalino presented some of her latest findings to delegates attending the 13th International Equitation Science Conference, ISES Down Under 2017 at Charles Sturt University in Wagga Wagga, New South Wales.
In their study, Dr Padalino and colleagues examined the relationship beween behaviour during transport and the occurrence of respiratory inflammation.
To first understand the issues and practices related to transporting horses, Dr Padalino and colleagues previously designed a survey and analysed the responses of 797 Australian horse owners involving approximately 17,000 horses and 313,000 individual horse transport events.
The results, which were published in the Australian Veterinary Journal, confirmed there are significant health and welfare risks associated with horse transportation, particularly during long journeys and in Spring.
In the survey, 67% of respondents had experienced transport-related health problems during or after transportation.
Although respondents identifying as amateurs transported horses less frequently and over shorter distances, the incidence of transport-related problems was similar between amateurs and professionals.
The most common problems reported in this survey included:
- Traumatic injuries (45%),
- Diarrhoea (20%),
- Muscular problems (13%),
- Respiratory problems (12.3%),
- Over-heating (10.5%), and
- Colic (10.3%).
Importantly, in the two years reviewed in the survey, 9.4% of participants reported at least one case of transport-related pneumonia and 35 transported horses had died, most commonly from fractures, colic or pneumonia.
Previous research had already identified transportation aggravates pre-existing respiratory disease; in other words, if you transport a sick horse, you will end up with a sicker horse at the other end.
Dr Padalino and colleagues, however, questioned whether a high level of stress during transport could play a role in the progression of disease and could, therefore, be used to identify those individuals who are at risk of developing respiratory illness post-travel.
To investigate this particular question, 12 horses – all experienced travelers – were transported on an eight-hour journey.
The horses were split into two groups, which travelled the same route, in the same horse truck on two separate days. They travelled side-on in a six-horse truck and were tied long enough to allow a low head-neck posture during the journey.
All horses received a series of health examinations before departure and straight after unloading, as well as one day and five days post-travel.
A tracheal wash was performed to collect mucous from the respiratory tract and to identify the presence of bacteria in the airways. Blood samples were also taken and analysed.
In addition, during the journey, each horse was video recorded, and their behaviour during the entire journey was later evaluated and documented.
Blood test results and examinations confirmed transportation is stressful. The journey caused an increase in blood glucose and cortisol – a hormone which is commonly used as an indicator of stress, as well as increased heart rate and respiratory rate. These parametres were restored after 24 hours post-travel.
Lactate and the enzyme creatine kinase (CK) was also increased post-journey, both of which indicate some level of muscular stress and fatigue. These levels were still high 24 hours after unloading, showing horses need at least (if not more than) 24 hours rest after an eight-hour trip to recover.
When it came to inflammation of the airways, Dr Padalino remarked she was surprised by the results of the tracheal washes. Neutrophils (pus) in the lungs were significantly increased following transportation for all horses, which indicates the journey activated an immune response in their bodies.
Despite the increase in mucous, some horses came back with a transparent tracheal wash and others came back with an opaque one. The researchers found a clear correlation between the quantity of bacteria and the colour of the wash.
“If you see yellowish, greenish nasal discharge in a horse after transportation,” Dr Padalino says, “you can predict that horse is full of bacteria and probably needs to be seen by a veterinarian as soon as possible.”
Six of the horses in the study were identified as having abnormal respiratory sounds during auscultation at the time of unloading, while the other six were normal. The six affected horses also had pre-travel inflammation of the trachea, so Dr Padalino recommends, particularly over long distances, owners should make sure there is no sub-clinical respiratory inflammation before moving them.
“Our research indicates that prior health status is a vital indicator of the horses’ ability to cope with periods of extended transportation, but it also suggests that there is great merit in examining horses prior to travel to ensure optimal health and prevent a higher risk of adverse effects following transport.”
When it came to behavioural signs, Dr Padalino said the findings confirmed a high head position was a good indicator of tracheal inflammation post-journey.
She remarked, compared to a normal day at pasture when horses spend most of their time with their head around wither height or lower, during the eight-hour transport journey, the horses spent a great deal of their time with an elevated head position – already a known risk factor for pneumonia.
And, in this study, head position correlated with tracheal inflammation; horses who spent more time with their heads in an elevated position during the journey had increased mucous and bacteria in their tracheas.
In general, the behaviours observed during the eight-hour journey in this study were strongly influenced by the stage of the journey.
In the first hour, there was an increase in behaviours indicative of stress, which decreased as the journey progressed.
Behaviours related to balance (including leaning, stumbling or shifting the feet), which were high during the first hour, tended to decrease until around the fifth hour of travel when they increased to peak at the eighth hour of travel (as horses tired), with many losses of balance recorded towards the end of the journey.
“Next time you must travel for extended periods with your horse, pay attention to [their] behaviour,” Dr Padalino warns.
“The use of on-board cameras makes this task much easier. If you have noticed, during a journey, that your horse has spent an extended period of time with [their] head in the air or you feel that the horse has displayed behaviours which might indicate a high level of stress, it would be wise to follow-up over the following days with a full examination in order to catch any resulting illness early and treat any immunological challenge with timely intervention.”
“After a long journey,” Dr Padalino continues, “put your horses out on pasture, so they can have their heads down and are able to clear their tracheas by themselves.”
During question time, Dr Padalino also remarked horses need enough space inside the truck or float to lower their heads and, in many cases, the internal design of horse trucks is not always conducive to this, particularly for very large horses.
“The horses in this study all had the same space, but there was a correlation between bodyweight and time spent with their heads down – the smaller horses, who would have had more room inside the truck, spent more time with their heads lowered.
“It would be interesting to see if there are other ways we can motivate the horse to put [their] head down,” she concludes. “For example, by placing dampened hay on or near the floor.”
Transport-related illness can be multi-factorial, but this study showed a link between behaviour during the journey and later health outcomes.
As well as monitoring horses before and after the journey, watching and paying particular attention to behavioural indicators of stress during the journey might help to predict impending illness at the other end.
The abstract for Behavioural, Clinical and Respiratory Responses to 8-hour Transportation in Horses by B. Padalino, S. L. Raidal, P. Knight, P. Celi, L. Jeffcott and G. Muscatelo can be found on Page 39 of the Proceedings of the 13th International Equitation Science Conference.
The published version of the study is available in the open access journal Plos One if you click here.
Assessing fitness to travel, and evaluating different training and management practices to reduce stress-related behaviour during travel will be the subject of Dr Padalino’s next presentation at ISES 2018 Rome, the 14th International Equitation Science Conference.
Dr Padalino’s tips for safe horse transport:
Prior to any travel
- Train your horse to self-load and to stand quietly, so all journeys start with minimum stress and fatigue.
- Ensure your float design allows your horse to balance and lower their head during every journey.
- Check your horse’s vital signs regularly, so you know what is ‘normal’ for your horse.
- Install a camera inside your float to monitor your horse during every journey.
Before a long journey
- Check your horse’s temperature. An elevated body temperature is one of the first symptoms of disease.
- Check your horse’s capillary refill time. Press your index finger on the gum, above the third incisor and hold for 2-5 seconds then release. Count in seconds the time it takes for the capillaries to refill and the gum colour to return. The normal is less or equal to two seconds.
- If you have any doubts about the health of your horse don’t travel and, instead, consult your vet. A sick horse will only get sicker during the journey.
During the journey
- Make sure your horse can lower their head comfortably during every journey. If possible and safe, motivate this head lowering by placing some dampened hay low down.
- Monitor your horse during every journey, noting signs of stress. Pay particular attention to the amount of time spent with the head above and below wither height.
After the journey
- Check your horse’s vital signs and record them.
- Continue to monitor and check on your horse for the next 5-7 days after a long journey. Consult your vet immediately if you are in doubt.
- Opaque, yellowish or greenish nasal discharge is a sign of bacterial infection. Consult your vet without delay.
- If your horse spent much of the long journey with a high head position, or displayed signs of stress and fatigue, follow up with a full vet examination and continue to monitor for early signs of disease.
- Allow at least 24 hours rest after a long journey. In addition, put your horse out on pasture for 24 hours, so they can clear their airways naturally.
This article was published in Horses and People April 2018 magazine.