Two European Slow Feeders for Horses Compared
Slowing the rate that a horse eats his hay is good for his health and welfare. Not only does it take up more of his free time, staving off boredom and mimicking natural grazing conditions, but it also makes him chew more. More chewing means better digestion in a species equipped with a particularly sensitive digestive system.

As the concept grows within the industry, so does the selection of slow-feeders. That’s why scientists in Switzerland recently tested two popular slow-feeders and compared them to each other and to ground feeding. They found that both work equally well—and that both were much better in slowing consumption and increasing chewing than ground feeding.

“In the feeders we saw with our study population, the positives and negatives essentially evened out,” said Margaux Reboul Salze, MSc, researcher on internship at the Agroscope research center at the Swiss National Stud, in Avenches. “While slow feeders have definite advantages over ground feeding, the best choice of slow feeder will really come down to whatever criteria matter most to the handlers.”

In their study of eight horses (seven stallions and one gelding), the researchers fed horses their daily hay rations in three ways: on the ground and via two commercial slow-feeders. The “B&M” slow feeder dispenses feed through a metal grill-like structure lying over a metal trough attached to a wall. The “HeuToy” feeder releases hay through several 5-inch-wide holes in a metal half-cylinder distributor attached vertically to a wall. Under the direction of Anja Zollinger, BSc, scientific collaborator at Agroscope, Reboul Salze, and Vera Hofer, BSc, presented their work at the 2017 Swiss Equine Research Day.

The horses’ consumption rate slowed considerably with the slow feeders, Reboul Salze said. The specific times varied considerably from horse to horse in this pilot study, despite each having three weeks to adapt to the new feeder before testing began. But on average, it took the horses about 30% longer to eat from the feeders compared to the ground.

They also chewed more than 40% more than when eating off the ground. “This additional chewing is more like in a natural setting, breaking up the food more and causing more release of saliva for improved digestion,” she said.

These benefits do come at a price, however. Not only do they have an initial cost (€140 [roughly $170] for the HeuToy and €295 [about $350] for the B&M) but they also tend to break from use to the point of having to be replaced—in some cases within a month, Reboul Salze said. Plus, they require more labor: “It takes about 50% longer to fill the feeders compared to just placing it on the ground,” she said.

There could potentially be a cost to the horses, as well, she added. “Especially with the HeuToy feeder, we noticed that the horses spent a considerable amount of time leaning their heads to the side in an unnatural position,” Reboul Salze said. “Once they grabbed the hay, they put their heads back in a natural position. But what effect that might have on their musculoskeletal health, we don’t know at this point.”

Their research, headed by Zollinger, is ongoing.