Dyson S and Pollard D (2020) Application of a Ridden Horse Pain Ethogram and Its Relationship with Gait in a Convenience Sample of 60 Riding Horses. Animals 10, 1044; doi:10.3390/ani10061044
Our inability to recognise when equines are experiencing pain has been identified as one of the priority welfare issues affecting our domestic equines. Not recognising when our equines are suffering means that action is not taken to alleviate the pain they are in. This can lead to equines in pain being expected to work or compete and may result in the delayed euthanasia of equines whose quality of life is compromised. Assessing whether or not our equines are experiencing pain can be highly challenging. As a prey species it is simply not in an equines bests interests to draw attention to the fact that they are in some way impaired, it would be inviting a predator to pick you off as an easy meal. So, our equines are naturally very good at hiding their pain. But there are subtle signs that can be used to identify when something is not right. These include changes in behaviour and facial expression, particularly postural changes and features of the eyes, mouth and nose. The subtlety of these pain indicators means that people caring for or working with equines may not notice them, and even if they do, many people are not aware that these changes in behaviour and facial expression indicate that their equine is experiencing pain.
Identifying pain in horses that are being ridden can add another level of difficulty to the challenge of recognising equine pain. Dr Sue Dyson and her colleagues at the Animal Health Trust recently developed the Ridden Horse Pain Ethogram (RHpE) which can be used to assess horses undergoing ridden work for evidence of pain. The ethogram consists of 24 behaviours that are seen at much higher levels in horses experiencing pain than in horses without. The development and testing of the ethogram focused on lame horses, with horses that were not lame or whose lameness had been eliminated with pain relief as comparison groups. Lameness is a common complaint in domestic horses, particularly those in ridden work, and like pain itself it is notoriously under recognised.
In this paper, the authors report the results of using the RHpE on a sample of riding horses that had been voluntarily entered into the study by their riders. These horses were either privately owned or from a riding school at a further education establishment. All horses were in regular work and considered to be comfortable while working by their regular rider. At the beginning of the study the thoracolumbosacral region of each horse was assessed by a physiotherapist, and the fit of each horse’s saddle was assessed by a master saddler. The soundness of the horses was initially assessed in a free exercise warm-up; four horses were excluded from the study at this point after scoring ≥ grade 3/8 lameness in either their front or hind limbs, leaving 60 horses to go forward to the ridden task. Each horse was ridden in a standardised dressage type test by their usual rider. The test included walk, trot and canter and lasted approximately 8.5 minutes. During the test an experienced assessor evaluated the horses’ gait. The RHpE was applied retrospectively from video footage, and the same footage was also used by a qualified riding instructor to grade the skill of each rider.
What the researchers found makes for concerning reading considering that all of the horses volunteered for this study by their riders were in regular work and believed to be working comfortably by their riders. The physiotherapist identified pain or tension in the thoracolumbosacral region of 58% of the 60 horses tested. The master saddler reported that 47% of the horses had issues with the fit of their saddles that was likely to negatively affect performance. Lameness was observed in 73% of horses typically at a low grade, and 47% had abnormalities in canter, with 37% of horses having both of these issues. RHpE scores ranged from 3 to 16 out of 24, with a median value of 9. Previous research had determined that a score of 8 or more was likely to indicate that the horse was experiencing musculoskeletal pain. Worrying, 10 out of the 11 riding school horses exhibited gait abnormalities that were consistent with musculoskeletal pain. The skill of the riders as graded subjectively on a 0-10 scale by the qualified instructor ranged from 2.5 to 8 with a median of 4.75, and had a negative correlation with RHpE score. This meant that the greater the skill of the rider, the lower the RHpE score, although it should be noted that the relationship between rider skill and RHpE score is likely to be complex rather than casual.
The horses were frequently observed with lameness in more than one limb which the authors stated can affect the accuracy of grading. Moreover, lameness was not always continuous in nature, becoming more obvious when the horses were trotted on a 10-metre circle. These features can increase the challenge of identifying lameness and scoring it accurately. However, throughout the study it was evident that the riders, regardless of skill and experience, simply did not recognise that the behaviour their horses were exhibiting may reflect musculoskeletal pain. The authors speculate that this may be a consequence of people learning to ride on riding school horses exhibiting these behavioural signs; the behaviour becomes normalised and riders accept it as such without questioning what it may reflect and take this acceptance with them when they ride horses in future.
The authors explored the data generated by the study to investigate factors that may influence RHpE score using different statistical techniques which I won’t go into here. The small sample size and large amount of variation between individual horses and their associated factors may have limited the ability to identify significant factors that influenced the pain score, leaving the presence or absence of lameness as the only significant factor associated with the RHpE score in the final statistical model.
For me, it is the descriptive data that are the important findings coming out of this study. These data highlight how widespread pain may be in our ridden horses and how poor we are at recognising it. But for me this study also has a positive element. The development of tools such as the RHpE give us the means to identify and assess pain in our equines. They can be used to educate us on what behavioural signs we need to be looking out for, and to illustrate how subtle some pain indicators can be. They also provide an evidence-base that some of the behaviours commonly seen in our riding horses are not normal and should not be accepted as such; they reflect an underlying problem that needs to be identified and resolved to alleviate pain. These tools make us look at our horses more closely, and question what we see and what we had previously accepted. And that can only be a good thing for equine welfare.