Humans show pain through facial expressions which have been coded and used to assess the discomfort of patients who cannot communicate their suffering in other ways, such as babies.

Scientist have done the same for laboratory animal (for example the “Mouse Grimace” scale).

And now the Horse Grimace Scale has been developed.

I read a recent article from Horse Journal’s John Strassburger with interest about a study done by European researchers to quantify horse facial expressions in order to determine degrees of pain.

They’re calling their new tool the Horse Grimace Scale (HGS), and the researchers hope that its application will help guide trainers, owners and veterinarians in the determination of equine pain and its care….

They conducted the study after castration of 46 males, with one group receiving Banamine prior to the procedure and one group receiving it both before surgery and six hours after surgery. High-definition video of the horses’ faces were then taken for five days after their procedures, and then they analyzed the footage.

Things which were delineated as being expressions of pain in horses included: stiffly backward ears, orbital tightening, tension visible above the eyes, strained chewing muscles, mouth strained with pronounced chin, strained nostrils, and what is described as “flattening of the profile,” which (I’ll be honest) I don’t really understand.

I was interested in this study because we spend countless hours trying to discern the meaning of every change in behavior, of an odd twitch of a tail or ear, looking for the Rosetta stone of movement, sound and behavior. And when something about them changes, you start running down the laundry list of possibilities.

“Do they hurt?” If yes, is it a new injury? An old injury? An issue with tack fit? With their teeth? With their feet or shoeing? Is it curable? Is it progressive? If so, how fast?

“Is it a training issue?” If yes, then, is it a hole in their basics? A question they don’t understand? A mismatch between horse and rider? A mismatch between horse and job?

“Is it a lifestyle issue?” Do they need more turn-out? Less turn-out? A different stall? A different neighbor or pasture mate? More schooling? More hacking? Different feed? Some kind of supplement? Removal of a supplement?

Working with horses, our gut feelings can lead us in the right direction or down the wrong path. The more we learn about the science of how horses think, the better we can communicate with them – don’t you think?