Over time, horses have evolved to be trickle feeders, meaning they consume small amounts of forage at once without long periods of fasting between. Horse owners use hay nets and other slow feeders to encourage trickle feeding, especially in thrifty breeds that become obese when offered free-choice hay. However, questions remain about the effects of hay nets on horses, so scientists recently explored these areas.

“We wanted to do this research because the majority of horse owners use hay nets, and limited research has evaluated impacts on horse health, especially when horses were offered free choice hay,” said Michelle DeBoer, PhD, associate professor in the Department of Animal and Food Science at the University of Wisconsin, in River Falls.

Horse owners also use hay nets as a way to reduce hay waste, which in turn saves them money, she said. And, for obese horses with weight-related health problems, hay nets can help reduce hay intake rate, prolong foraging time, and reduce boredom, she added, which can reduce their risk of health complications related to prolonged periods of fasting, such as gastric ulcers.

The Effects of Hay Nets on Equine Body Condition

During the first phase of the study, the DeBoer and her colleagues randomly assigned 13 adult horses to either hay-net or no-hay-net feeding groups for one full year. After one year, the researchers switched the groups and repeated the research for another year. Over the course of the study, they regularly evaluated each horse’s dental health and body condition score and noted any changes.

“We offered free-choice hay in this study, while previous studies evaluated restricted hay intake,” said DeBoer. “Also in our study, despite hay-net use, all of our horses remained at healthy weights and body condition scores on hay-only diets (with vitamin and mineral supplementation, based on each horse’s needs). While I would say it is important to monitor horses that are typically hard keepers, I wouldn’t necessarily rule out using hay nets for those horses and would take it on a case-by-case basis based on how the horse responds to this management practice.”

The researchers found the horses’ body weight and their body condition scores were greater when fed without a hay net. They also found that hay nets reduced horses’ hay usage by 20%, due to a combination of lower intake and less waste, so it does not necessarily mean they ate 20% less.

Historically, owners and veterinarians have not reported a reduction in body weight or condition using hay nets, the researchers said, attributing it to sufficient amounts of hay provided in the nets. 

The Effects of Hay Nets on Equine Dental Health

“One of the biggest questions we have received with hay nets are how they impact the teeth, and many people worry they have the potential to cause damage and are too abrasive—we wanted to get an answer to this question,” said DeBoer.

The researchers monitored characteristics ranging from tooth length and bevels on the teeth (evaluating wear) to dental abnormalities and conditions.

“Fortunately, hay nets did not have negative effects on dental health over the course of a year,” said DeBoer. Feeding horses from hay nets did not cause bevels (slopes) on the incisors, and horses had the same number of dental issues, regardless of their hay-net status.

“It is important to provide regular dental work on a horse regardless of hay net usage, however,” she added.

Take-Home Message

Hay nets can help horse owners reduce hay waste and prolong feeding time which can reduce horse boredom and promote a more natural style of trickle feeding without negative effects to the horse’s dental health. Always work with your veterinarian before changing your horse’s feeding and management routine to discuss any concerns you might have.

The study, Effect of hay nets on horse bodyweight, body condition score, hay usage, and dental health in mature horses, was published in the Journal of Equine Veterinary Science in May 2024.