The Ridden Horse Pain Ethogram (RHPE) is a comprehensive tool used by equine professionals to identify musculoskeletal pain in horses while being ridden. It consists of a list of 24 behaviors associated with pain and discomfort in horses under saddle.

Dr. Sue Dyson developed this ethogram as a means of identifying low-grade lameness and discomfort in horses during ridden work. Early identification of lameness can improve horse welfare by enabling medical treatment prior to overt lameness.

To complete this evaluation, the horse is observed over a 5–10-minute period, with the evaluators looking for the 24 behaviors described in the RHPE. Horses that display 8 or more of the behaviors are likely to have musculoskeletal pain.

Studies show that the RHPE can successfully distinguish between lame and non-lame horses under saddle and can predict performance in dressage and eventing competitions.

Other applications of the RHPE include use during pre-purchase examinations to identify low-grade lameness. The ethogram may also help riders and saddle fitters identify poor saddle fit in horses experiencing pain from their tack.

What is an Ethogram?

An ethogram is a systematic list of behaviors performed by a particular animal species. [1] It catalogs the various actions, movements, and responses observed in the natural behavior repertoire of the animal.

Ethograms are used in ethology, the scientific study of animal behavior, to document and analyze behavioral patterns, social interactions, communication signals, and other aspects of animal behavior.

Most ethograms catalogue behaviors displayed by a species during a particular scenario, such as maternal interaction with their offspring. [2]

Studying behavior requires observation of the animal and interpretation of their actions, which is often subjective. [3]

Researchers and veterinarians use ethograms as a way of objectively measuring an animal’s behavior for scientific purposes. [3] Objective measurement minimizes the risk of subjectivity and increases the validity of scientific studies, making their findings more impactful. [3]

Equine Ethograms

In horses, there are several ethograms available for different scenarios. There is also a comprehensive catalogue that aims to describe all known behaviors of equids, so that researchers can use these descriptions as a starting point for their own ethograms. [2]

Equine ethograms currently exist for: [2][4][5]

  • “Maintenance behaviors” such as eating, drinking, and seeking shelter
  • Social communication
  • Interaction between males
  • Reproductive behaviors
  • Play behaviors
  • Pain and discomfort
  • Stereotypies such as cribbing, weaving, and wood chewing

Creation of an Ethogram

Ethograms are particularly impactful in veterinary medicine, as veterinary patients cannot speak to describe the pain or discomfort they are experiencing. For this reason, researchers are developing ethograms to objectively identify behaviors associated with pain in animal species.

Objective identification of pain behavior improves animal welfare by indicating a need for prompt medical intervention. [1]

To start making an ethogram, researchers select a list of behaviors to include. [6] These behaviors must have detailed, specific descriptions that allow observers to make an objective judgment as to whether the behavior is present. [3]

Ideally, researchers developing the ethogram will perform a study confirming that the descriptions are comprehensive, understandable, and have a high degree of agreement between observers. [6]

After establishing the behavior list, many researchers use the Delphi technique to finesse the ethogram model. [6] The Delphi technique involves consulting numerous experts and having them weigh in on the behavior list, ranking the behaviors based on their interpretation of the each one’s significance. [6]

The researchers then calculate the most significant behaviors using the rankings established according to the Delphi technique. [6] The final ethogram is then subjected to validation studies, where the researchers apply the ethogram to both healthy horses without known pain and horses expressing pain or discomfort. [6]

A successful ethogram will show a significantly higher behavior score for horses expressing pain or discomfort, indicating its validity as a diagnostic tool. [6]

The Ridden Horse Pain Ethogram

The Ridden Horse Pain Ethogram (RHPE) is an ethogram developed by Dr. Sue Dyson et al., with the goal of identifying behaviors associated with musculoskeletal pain in horses under saddle. [1] Veterinarians, researchers, and equestrians can use the RHPE as a method for diagnosing low-grade lameness in performance horses. [1]

Many studies using the RHPE currently focus on welfare evaluations of horses performing at competitive events, to examine whether horses are fit and sound enough to compete. Current studies show a correlation between RHPE score and performance in dressage and eventing, with horses that have lower RHPE scores placing higher in competition.

Although the RHPE has several validation studies in English discipline horses, further research is necessary to finesse the RHPE and ensure its validity across disciplines and groups of horses.

Development of the RHPE

The initial behavior list for the RHPE included 117 behaviors previously described as indicators of conflict or pain in horses. [1][7] An experienced reviewer observed videos of 9 horses, both lame and non-lame, and identified whether each of the 117 behaviors occurred during the video. [7]

From these evaluations, statistical analysis showed that 27 behaviors occurred up to three times more frequently than other behaviors. [7] Additional analysis further narrowed the selection down to 24 behaviors that make up the final ethogram. [7]

Evaluation of videos using these 24 behaviors as a reference showed that lame horses typically scored a 9 or higher. [7] Sound horses had a maximum score of 6 and averaged a score of 2. [7] Using this information, the researchers established a threshold score of 8 or higher to distinguish between a lame and non-lame horse. [7]

Validation of the RHPE

The researchers involved in creating the RHPE performed additional studies to confirm the efficacy of RHPE as a diagnostic tool for lameness. [1] In total, 491 lame and non-lame horses were examined across 3 additional verification studies. [1] In all three studies, the RHPE successfully identified lame horses, with most lame horses having a score of 8 or higher. [1]

Additional studies examined whether RHPE scores decreased after numbing a limb showing signs of lameness. [8][9] These studies showed that the average RHPE score in lame horses decreased from 9 to 2 with numbing, indicating that the RHPE could successfully identify resolved lameness. [8]

Finally, the researchers also investigated whether evaluations using the RHPE were repeatable, or if multiple observers would arrive at similar results when evaluating the same horses. [10] These studies showed that veterinarians were able to consistently apply the RHPE after a training session describing the use of the ethogram. [10]

Mad About Horses
Join Dr. Chris Mortensen, PhD on an exciting adventure into the story of the horse and learn how we can make the world a better place for all equines.
Apple Podcasts Spotify Youtube
Mad Barn - Equine Nutrition Consultants | Mad Barn USA

What are the 24 signs of pain in the ridden horse?

The Ridden Horse Pain Ethogram identifies 24 behaviors associated with pain. These behaviors are: [1]

  • Changing the position of the head up/down out of rhythm with the trot
  • Tilting the head
  • Head in front of vertical for more than 10 seconds
  • Head behind vertical for more than 10 seconds
  • Regular changes of head position including tossing or twisting from side to side
  • Ears rotating backwards or flat
  • Frequent blinking or holding the eyelids closed for 2-5 seconds
  • Exposing the whites of the eye repeatedly
  • Intense glazed over stare for more than 5 seconds
  • Opening and shutting of the mouth repeatedly for more than 10 seconds
  • Tongue sticking out or moving in and out repeatedly
  • Bit pulled through the mouth repeatedly
  • Tail held clamped down or held to one side
  • Large, repeated tail swishing movements
  • Rushed gaits or irregular rhythm
  • Slow gaits
  • Hindlimbs following a different track than forelimbs repeatedly
  • Repeated canter lead changes in front or behind
  • Changing gait repeatedly such as breaking from canter to trot
  • Stumbling or tripping
  • Sudden changes of direction such as spooking
  • Reluctance to move forwards
  • Rearing
  • Bucking or kicking out

Horses displaying eight or more of these behaviors during a 5–10-minute period likely have musculoskeletal pain, according to the research behind the RHPE. [1]

Use of the Ridden Horse Ethogram

The Ridden Horse Ethogram has several potential applications for veterinarians, researchers, and horse owners. [1]

Currently described uses include: [1][13]

  • Component of lameness examination for low-grade lameness or poor performance
  • Pre-purchase examinations to identify low-grade lameness
  • Assessing response to saddle fit
  • Screening tool to identify horses at risk of injury or poor performance during competition
  • Randomly sampled welfare evaluations at competitions

Most studies using the RHPE currently focus on welfare evaluations at different levels of competition. [1] Studies show that horses placing higher in competition typically have lower RHPE scores, and horses with RHPE scores over 8 are more likely to be eliminated, withdraw, or retire from competition. [13]

Welfare evaluations of this type have been performed in low-level eventing, five-star eventing, and Grand Prix dressage to date. [13][14][15][16]

How to Use the RHPE

The researchers developing the RHPE recommend that all observers attend a training course on how to use the RHPE before performing evaluations. [1] Studies show that prior training improves the consistency of RHPE application, making the evaluations more effective. [1]

Evaluation using the RHPE begins by the rider warming up the horse in walk, trot, and canter in both directions using their typical warm-up protocol. [1] The observer then evaluates the horse at all three gaits from both sides, the front, and the rear. [1]

Depending on the horse’s level of training, additional movements such as small circles, figures of eight, or collected movements may be included in the evaluation. [1] The researchers recommend including these movements because some horses only display pain behaviors when asked to perform more physically taxing maneuvers. [1]

In total, there should be an observation period of 5 to 10 minutes. [1]

While observing the horse, the evaluator notes whether the behaviors identified in the RHPE occur. [1] The researchers advise using a checklist with each of the behaviors listed during the evaluation process. [1] Some behaviors are time dependent (e.g. ears back for more than 5 seconds), so a stopwatch should be used to evaluate these behaviors to maximize objectivity. [1]

After the evaluation, the observer totals the number of behaviors within the ethogram displayed by the horse. [1] Horses displaying 8 or more behaviors likely have some degree of musculoskeletal pain. [1]

Factors Influencing Ethogram Score

The researchers developing the RHPE have identified several factors that may increase the ethogram score. [1] Many of these factors are indirectly related to musculoskeletal lameness but may explain ridden pain behaviors in horses that do not show lameness without a rider. [1]

The observer should consider the presence of these factors before performing an RHPE evaluation. Factors include: [1][17]

  • Saddle fit
  • Horse-to-rider weight ratio
  • Rider skill
  • Tack selection, including excessively tight nosebands or harsh bits
  • Other painful conditions often irritated by riding, such as oral pain or gastric ulcers
  • Development of behavioral habits due to training

Limitations of the RHPE

Experts have identified several limitations of the Ridden Horse Pain Ethogram as a diagnostic tool. [11] Concerns about the RHPE in its current form include: [11]

  • Some behavior descriptions require subjective interpretation
  • Ambiguous language within the behavior descriptions requires interpretation
  • Influence of factors such as different ground surfaces, environmental conditions, non-musculoskeletal health concerns, etc.
  • Influence of the horse’s previous training (habit formation)
  • All the behaviors have equal weighting in the ethogram, despite some behaviors being more extreme indicators of pain, e.g. bucking or rearing
  • Behavior selection did not include horses from diverse riding styles, only English disciplines
  • Some lame horses do not score higher than 8 on the RHPE score system

Further research integrating the knowledge of many equine veterinary specialists and behaviorists is necessary to finesse the RHPE and ensure its validity in all circumstances. [11] Recent studies indicate that minor adjustments to the RHPE may be necessary to optimize the ethogram for different groups. [12]

Summary

The Ridden Horse Pain Ethogram describes 24 behaviors associated with musculoskeletal pain in the ridden horse.

  • The RHPE may help identify lameness during lameness examinations, pre-purchase examinations, or during competitions
  • Horses that display 8 or more of the behaviors in the ethogram likely have musculoskeletal pain
  • Studies show that the RHPE can successfully identify lame versus non-lame horses under saddle with good repeatability between observers
  • Further research is necessary to finesse the RHPE and ensure its validity in a wider variety of equestrian sports

Is Your Horse's Diet Missing Anything?

Identify gaps in your horse's nutrition program to optimize their well-being.

References

  1. Dyson, S. The Ridden Horse Pain Ethogram. Equine Veterinary Education. 2022.
  2. MacDonnell, S.M. The equid ethogram: a practical field guide to horse behavior. 1st ed. Lexington, KY: Eclipse Press, 2003.
  3. Pierard, M. et al. Reliability of a Descriptive Reference Ethogram for Equitation Science. Journal of Veterinary Behavior. 2019.
  4. Torcivia, C. and McDonnell, S. Equine Discomfort Ethogram. Animals. 2021. doi: 10.3390/ani11020580.View Summary
  5. Sutton, G.A. et al. Validation of Two Behaviour-Based Pain Scales for Horses with Acute Colic. The Veterinary Journal. 2013.View Summary
  6. Sutton, G.A. et al. A Behaviour-Based Pain Scale for Horses with Acute Colic: Scale Construction. The Veterinary Journal. 2013.View Summary
  7. Dyson, S. et al. Development of an Ethogram for a Pain Scoring System in Ridden Horses and Its Application to Determine the Presence of Musculoskeletal Pain. Journal of Veterinary Behavior. 2018.
  8. Dyson, S. and Pollard, D. Application of the Ridden Horse Pain Ethogram to 150 Horses with Musculoskeletal Pain before and after Diagnostic Anaesthesia. Animals. 2023.View Summary
  9. Dyson, S. et al. Behavioral Observations and Comparisons of Nonlame Horses and Lame Horses before and after Resolution of Lameness by Diagnostic Analgesia. Journal of Veterinary Behavior. 2018.
  10. Dyson, S. et al. Can Veterinarians Reliably Apply a Whole Horse Ridden Ethogram to Differentiate Nonlame and Lame Horses Based on Live Horse Assessment of Behaviour?. Equine Veterinary Education. 2020.
  11. Ladewig, J. et al. A Review of The Ridden Horse Pain Ethogram and Its Potential to Improve Ridden Horse Welfare. Journal of Veterinary Behavior. 2022.
  12. Garcia, H.D. et al. Application of a Ridden Horse Pain Ethogram in Icelandic Horses: A Pilot Study. Equine Veterinary Education. 2023.
  13. Dyson, S. and Pollard, D. Application of the Ridden Horse Pain Ethogram to Horses Competing in British Eventing 90, 100 and Novice One-Day Events and Comparison with Performance. Animals. 2022.View Summary
  14. Dyson, S. and Ellis, A.D. Application of a Ridden Horse Pain Ethogram to Horses Competing at 5-Star Three-Day-Events: Comparison with Performance. Equine Veterinary Education. 2022.
  15. Dyson, S. and Pollard, D. Application of the Ridden Horse Pain Ethogram to Horses Competing at the Hickstead-Rotterdam Grand Prix Challenge and the British Dressage Grand Prix National Championship 2020 and Comparison with World Cup Grand Prix Competitions. Animals. 2021.View Summary
  16. Dyson, S. and Pollard, D. Application of the Ridden Horse Pain Ethogram to Elite Dressage Horses Competing in World Cup Grand Prix Competitions. Animals. 2021.View Summary
  17. Dyson, S. How to Determine the Presence of Musculoskeletal Pain in Ridden Horses by Application of the Ridden Horse Pain Ethogram. Proceedings of the American Association of Equine Practitioners. 2020.