You go to his stall, put his halter on him, lead him out away from his companions, and take him to that Great Contraption that he’s finally learned to accept. You guide him into the enclosure, tie him up, give him a friendly pat on the croup and tell him he’s a good boy, then close him up. You set the Contraption in motion, and you tell yourself, “Of course he’ll be fine.”
No, we’re not talking about a trailer ride, one of the greatest known sources of stress to horses. We’re talking about the automatic horse walker, one of the least known sources of stress to horses.
“Horses experience significant levels of stress while on a horse walker, as we’ve found, although there’s practically no research on the use of walkers available in scientific literature,” said Caitlyn Cuthbert, BSc ACHBC, in association with Writtle University College in Writtle, the U.K.
While Cuthbert’s work revealed high stress levels in horses on a walker—even in those that appeared, at first glance, calm—she did find that the stress levels weren’t quite as high when the animal was accompanied by a familiar companion.
“It’s probably better to find other solutions to walkers,” Cuthbert said during her presentation at the 14th Conference of the International Society for Equitation Science (ISES) in Rome, Italy. “But the final word is, if you have to use a walker, be sure the horse has a known companion with him.”
In their study, Cuthbert and her fellow researchers investigated the physiological and behavioural effects of walker use on 16 horses and ponies. The animals represented a variety of breeds, sexes, and ages and were all part of the Writtle University College Equine Training and Development Centre.
To evaluate those effects, the scientists equipped the horses and ponies with heart rate monitors, and they fitted each compartment of a six-compartment automatic track system walker with an iPhone for continuous video monitoring.
They found that, despite having had eight weeks of habituation to the walker, the animals averaged heart rates equivalent to moving at a gallop, although they were only walking, Cuthbert reported. This suggested they were experiencing high levels of stress, she explained.
The presence of a companion reduced those heart rates, however—although they were still high compared to what they should be for just walking—and increased heart rate variability (a sign of better welfare), she said.
As far as behaviour was concerned, some showed obvious signs of stress, like trying to escape the walker, while others had less obvious signs. “Horses don’t always show their stress overtly, and some of the signs might be too subtle to notice for people who haven’t studied animal behaviour,” Cuthbert said. “But they were definitely present in most of the horses, and some showed signs of stress for the entire time they were on the walker. A few of the horses were literally shaking from start to finish.”
Again, these same horses showed fewer signs of stress—whether subtle or obvious—when accompanied by a familiar companion, she added.
“It’s an act of cruelty to terrify an animal, yet some of these horses and ponies were clearly very afraid, just using equipment that many people consider to be normal, useful material that should make up a standard part of an equestrian facility,” Cuthbert said. “Any equipment or machinery or training tool that restricts natural behaviours is a welfare issue. I strongly believe that before something can be deemed ‘suitable’ for equine use, and sold, it should be tested against a stress grid (heart rate/behaviour) with actual everyday horses.”
Future testing with walkers should evaluate additional effects like social rank and order of placement in the walker, different kinds of walkers, and various training regiments to help horses learn to adapt without falling into the trap of learned helplessness, she said.
“We should also be looking at how other kinds of equipment, such as spas, stocks, and training aids affect horses’ stress levels, because all of these restrict natural behaviours,” said Cuthbert. “For ethical practice, it’s important to weigh the risks and benefits of such devices.”