The Horse Grimace Scale, developed by scientists in Italy, Germany and the UK, uses a standardised system, looking at features such as stiffly backward ears and orbital tightening.
Researchers from Italy, Germany and the UK have developed a standardised system to assist pain detection in horses.
Scientists say the Horse Grimace Scale (HGS) can be easily taught to laypersons and could positively impact the welfare of horses that have undergone routine surgical procedures such as castration.
Michela Minero, who presented the research group’s findings at the 2013 International Society for Equitation Science (ISES) conference in Denmark, said: “Annually, it is estimated that 240,000 horses are castrated in Europe, and castration has been shown to be associated with a certain degree of pain. However, only about 36.9% of horses receive analgesics for post-operative pain.
“One of the possible explanations for this is that the assessment of pain in horses undergoing castration is still sub-optimal.”
Using the HGS, facial actions such used to identify pain include:
- stiffly backward ears
- orbital tightening
- tension above the eye
- strained chewing muscles
- mouth strained and pronounced chin
- strained nostrils and flattening of the profile
According to Dr Minero, a study of horses undergoing surgical castration showed “a high degree of accuracy” in pain assessment when looking for these features eight hours post-op, measured at 73.3%.
She said: “These findings suggest that such a scale could indeed benefit those in the position of managing horses that have undergone painful procedures.”
However, it was also noted that darker coloured horses were harder to score than lighter coloured ones, while “how and when” the horse chooses to express pain could also make assessment harder.
For more information, visit the ISES website.