You might think you know your horse so well, you’d recognize pain on his face in a single glance.
Maybe you could. But chances are, you’d be missing something.
According to Dutch researchers, you need to observe a horse for at least a full two minutes to pick up subtle signs of pain in his facial expressions. And you’d need five minutes to recognize it in his overall body language.
You’d also have to know what parts of the face to look at, what changes you should notice, which muscles to check for tension, what behaviors to look for, and how frequently those behaviors happen in a short time frame. For veterinarians and owners alike, this isn’t always as easy as it might sound, said Thijs van Loon, DVM, PhD, of the Faculty of Veterinary Medicine Utrecht University, the Netherlands.
A Simple and Objective Tool
That’s why van Loon and his fellow researchers at Utrecht, including Machteld van Dierendonck, PhD, decided to develop a smartphone app for reading facial expressions and body language related to pain in equids. By walking the handler through the observation process, their app allows users to add objectivity and measurability to the art of reading equine facial expressions and body language.
“This was something I’ve wanted to do for years, since I first studied signs of acute pain represented in horses’ facial expressions and body language,” he said. “It really gives a simple and effective way of recognizing when a horse is in pain—even when those signs are subtle.”
As prey animals, equids—donkeys, in particular—tend to hide their expressions of pain, he said. However, trained observers can become skilled at picking up these subtle signs. As a result, they can address health issues quickly, leading to better resolution of the problem and improved animal welfare.
Designed with a user-friendly interface, the Equine Pain and Welfare App (EPWA) allows users to choose to evaluate either facial expressions or body language and whether they want to assess a horse or a donkey. Users then can start a two-minute timer for facial expressions or a five-minute timer for body language, during which time they can click on icons for certain expressions or behaviors each time they occur. The app counts these occurrences and then leads the user to a series of questions about the horse—how his ears are positioned, how he holds his head, what his eyes look like, etc.
The app doesn’t just do the work for the user, though. It also accompanies the user during that two- or five-minute observation period, van Loon explained. “Even if you know you’re supposed to stand there and watch the horse for five minutes nonstop, in reality that’s hard to do,” he said. “Having the app gives people something concrete in their hands to work with and interact with. It makes the observation process more feasible.”
Scoring Now and Over Time
Once users record and select their responses, the app provides a final pain score on a facial expressions scale of 0 (no pain) to 18 (maximum pain). Scores of 5 or higher might indicate the horse is in pain and lead to a recommendation to contact a veterinarian.
The scores aren’t just for indicating whether the horse is over the pain threshold, however. They also allow users to build measurable histories of their horses’ facial expressions and body language over time, as recorded in the app, to monitor changes.
That’s particularly useful because each horse, with his unique personality and ways of expressing himself, will have individual characteristics worth monitoring. “If you run the app on your horse regularly—say, once a week—then you can get a concrete record of what’s normal for him, and you can recognize patterns,” van Loon explained. “And more importantly, you can really recognize when his scores are far off his baseline, which should indicate to you that he’s probably experiencing acute pain.”
Training and Upcoming Features
“We’ve recently developed a web-based, interactive EPWA training program, which teaches people to improve their ability to recognize and score pain-related facial expressions,” van Loon said.
While the current version of the app—available in Dutch and English, with translations into French, German, and Spanish planned—is limited to signs of acute pain, van Loon said research is underway to integrate pain scales for chronic pain, as well. Chronic pain can arise from issues such as osteoarthritis, back pain, and foot pain, among others.
In the future, van Loon and his team plan to offer an optional feature on the app that would provide automatic reading of facial expressions. “It’s a sort of ‘Google translate’ from horse language to human language,” he said. However, that requires tens of thousands of photos of horse faces, along with expert readings of their facial expressions, so it’s still a work in progress.
A product of charitable funding through the faculty’s dedicated charity fund Friends of VetMed, as well as individual donations from nearly 250 horse owners, the app is nonprofit and free to download.