SPOTTING SIGNS OF EQUINE DEPRESSION
Research from France suggests that horses can develop something akin to depression in response to social or physical discomfort.
For a study conducted at University of Rennes 1, researchers selected 12 horses who were considered “withdrawn” and 15 who behaved normally. “Withdrawn horses are rather easy to identify as they have long bouts of five unusual sounds: baboon, goose and whale calls; the call of a horse not known to the study horses; and piano music. Each day each horse heard one of the sounds---played for three seconds from a speaker next the first day of the study, the withdrawn horses were significantly less likely to pay attention to the noises. Only 50 percent of those horses reacted to the noise--responding by pricking the ears, lifting the head or some other sign of attention---as opposed to 90 percent of the normal horses. Over the fiveday course of the study, the control horses showed habituation to the unusual noises, but the reactions of the withdrawn horses did not change significantly.
These findings, the researchers say, indicate that the withdrawn horses had undergone a cognitive shift: They were so physically or psychologically stressed that they had tuned out their surroundings.
“In humans and animals, being attentive is one aspect of subject cognitive abilities/ capacities,” says Rochais. “The delay in responding showed that withdrawn horses had ‘switched off’ from their environment and showed sensory inattention. Such lapses of attention are likely to be associated with the chronic effect of stressors, which might be expected to induce a lowered state of arousal.” She adds, “In humans, for example, pain or strong discomfort ‘captures’ the attention of the subject. Here we do not know precisely how the [horses] feel but they might have chronic disorders, which are one hypothesis for an ‘inwardoriented attention.’”
A growing body of research suggests that horses can enter a depression-like state as a reaction to their environment
or chronic pain.