Upon reviewing their results, the researchers found six reliable indicators of intensity and seven of valence, Briefer said. For example, increased respiration and body movement and high-frequency vocal sounds indicated increased intensity. | Photo: iStock

While it might sometimes seem obvious when horses are “happy” or “upset”—and how much so they are—in some situations the emotion isn’t so easy to read, said Elodie Briefer, PhD, of the Institute of Agricultural Sciences and the Swiss Federal Institute of Technology, in Zurich.

“Our indicators—especially the valence indicator—allow us to identify which situations provoke negative or positive emotions, and this knowledge will help promote better animal welfare,” Briefer said during the presentation of her research at the 2014 Swiss Equine Research Day held April 10 in Avenches.

Previous studies on equine emotions have focused more on intensity (cortisol, or stress hormone, levels and heart rate, for example) without necessarily identifying behavioral indicators that represent a positive or negative valence