Thursday, June 01, 2017

Sue Dyson: Double video explanation of equine ethogram for recognizing lameness and pain

Bad behavior or signs of pain? All the facial expressions shown here are part of the ethogram developed by Dr. Sue Dyson's research team at the Animal Health Trust in England. In a continuation of the research, recognition of facial expressions in both ridden and unridden horses has been recommended as a way to identify potential lameness, not just "naughty" behavior, with larger welfare implications. (Photos courtesy of Sue Dyson)

Researchers at the Animal Health Trust (AHT) Centre for Equine Studies in England have produced a practical tool to help owners, riders, and professionals recognize signs of pain by observing a horse’s facial expressions. The second part of the study was published recently, along with a new video, with a focus on facial expressions relationship to lameness. Both videos are included in this article.

The premise for the system is that, unfortunately, owners and trainers do not recognize changes in a horse's facial expressions as signs that a horse is displaying that it is in pain. This means a horse’s health and welfare can be threatened, as veterinary assistance is not sought early enough -- if at all.

The signs and system are explained in two short videos, totaling less than 20 minutes of the viewer's time. It's important that the entire video, particularly for part 2, be watched. The true gem occurs around nine minutes into part 2, when Dr Sue Dyson, Head of Clinical Orthopedics at the AHT,  reveals her blind comparison of faces of sound and lame horses; she also mentions how nerve blocks were used in the study to mask lameness, and the horses' facial expression scores changed.

In the first of two videos shown here, Sue Dyson explains:
  • the common problems mistaken for pain, 
  • why the study is so important, and 
  • what it could mean for both horses and humans in the future. 

Dr. Sue Dyson evaluating a contented-looking horses at the Animal Health Trust in England.

The first video has already ignited a lively debate online about equine behavior and body language. There have also been comments from owners who now feel guilty for not taking note of these facial expressions sooner to help their horses.

Other professionals agree that these expressions can be recognized, but are amazed at how often they are not.

The second video became available this week and is also shown here. It explains to people working with horses

  • an insight into how the "ethogram"--or collection of behavior signs--has been developed; 
  • how it was tested to ensure it could be applied by a broad range of people within the equine industry; and 
  • whether or not the ethogram is effective in not only helping recognize signs of pain, but could also be used to differentiate a lame horse from a sound horse.

The problem
There is undisputed evidence to show that owners, riders and trainers lack ability to recognize signs of pain seen when horses are ridden. As a result, problems are labelled as training-related, rider-related, behavioral, or deemed ‘normal’ for that horse because ‘that’s how he’s always gone’.

Unfortunately that means pain-related problems are often disregarded, the horse continues in work, and the problem gets progressively worse.

The facial expressions of these two horses were scored. The horse on the left received a score of 0 out of 3 for ears and mouth; the horse on the right scored a 3 out of 3 for its mouth. (Sue Dyson photos)

The aim
Recognition of changes in facial expression could potentially save horses from needless suffering and chronic injuries by enabling owners and trainers to perceive pain sooner, and get these horses the veterinary care that they need.

Developing a practical tool for recognizing these facial expressions, similar to that of an equine body condition score chart, could dramatically improve the health and welfare of all horses. This is something Sue Dyson and her team at the Animal Health Trust continue to work toward.

Watch the first video (about 7.5 minutes, published April 28):

Video 1. Facial Expressions Research - is your horse trying to tell you he's in pain?

The ethogram
The ethogram is a catalogue of facial expressions including the ears, eyes, nose, muzzle, mouth and head position. Each body part can display an expression which may be normal, or reflect pain, conflict behavior or distress.

Developing the ethogram
In its first stage of testing, the ethogram was successfully applied by a variety of people from different backgrounds to a selection of photographs of horses’ heads while they were ridden. Using the ethogram, these individuals could identify different expressions in each horse, such as positions of the ears, changes in the eyes, and tightness in the muzzle.

The results were highly repeatable among the analysts proving that, with guidance from the ethogram, owners could potentially reliably recognize different expressions in their horses' faces.

Dr. Dyson's second video was published on June 1, 2017, and explains the application of the ethogram in lameness recognition:

Video 2. Developing and Applying the Ethogram

Applying the ethogram:
Stage two tested if the ethogram could be used to distinguish between sound and lame horses. During this phase a pain score from 0 - 3 was applied to each of the facial expressions (mouth, eyes, ears etc.), and then totaled to determine an overall pain score for each horse. Sue Dyson categorized 519 photos of horses to be lame or sound; these were assessed.

An amazing total of 27,407 facial markers were recorded, with results showing that there was a scientifically significant difference in pain scores given by the assessor for clinically lame and sound horses.

The facial markers showing the greatest significant difference between lame and sound horses included:

  • ears back;
  • tipping the head;
  • eyes partially or fully closed;
  • tension around the eye; 
  • an intense stare;
  • an open mouth with exposed teeth; and 
  • being severely above the bit.

To further prove the effectiveness of assessing pain in a horse with the facial expressions ethogram, a selection of lame horses underwent lameness assessment and nerve blocking (using local anesthetic solution), to alleviate the pain causing them discomfort when ridden. Comparison of their facial expressions before and after using local analgesia showed a significantly lower pain score once the pain causing lameness had been removed.

The complete research from the AHT's ethogram project was published in two parts in the Journal of Veterinary Behavior this spring. Access to the journal is limited to subscribers or to libraries with Elsevier journal contracts. The papers can also be purchased online for downloading. You can read the abstract pages of both papers for no charge.

--Fran Jurga

Link to Stage 1 paper

Development of an ethogram to describe facial expressions in ridden horses (FEReq)

Mullard, Jessica et al.
Journal of Veterinary Behavior: Clinical Applications and Research , Volume 18 , 7 - 12

Link to Stage 2 paper

Can the presence of musculoskeletal pain be determined from the facial expressions of ridden horses (FEReq)?

Dyson, Sue et al.
Journal of Veterinary Behavior: Clinical Applications and Research , Volume 19 , 78 - 89

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