Hay feeders vs. free choice: What is best for horses?

Researchers have found that horses using automatic box feeders and slow feeders consumed less and had slower weight gain than horses given free choice of hay in their diet.

The results of the study that looked at the effects of roughage availability on behaviour and cortisol circadian rhythm have been published in the Journal of Equine Veterinary Science. Funded by the Morris Animal Foundation, the study sheds light on how to better care for horses by evaluating the effects different feeding methods have on equine health and well-being.

Feral and wild horses can spend about 16 hours per day grazing. Changing their access to food can affect their natural behavior and lead to health problems. To understand these changes better, researchers looked at several feeding methods including free-choice feeding or unlimited food access, slow-feeder, which also allows unlimited hay access but requires the horse to pull hay through a net, and an automatic box feeder.

One of the researchers, Jéssica Carvalho Seabra, from the Federal University of Paraná in Brazil, said taking care of horses means more than just giving them a place to stay, and providing food and water.

“It means giving them an environment where they can do things that are part of their natural behavior like grazing.”

The team found that horses using automatic boxes and slow feeders consumed less and exhibited slower weight gain. Both methods effectively regulated food intake. Horses with the freedom to choose when to eat had the highest hay utilization and weight gain rates, suggesting that this approach might not be optimal for overweight horses.

Horses with access to free choice feeding or a slow feeder spent more than half their day doing natural activities such as foraging. Conversely, horses using the box feeder spent only about a quarter of their day eating, and this treatment increased the time that horses spent standing, sniffing the ground and ingesting their own feces. Furthermore, horses using the box feeder displayed more signs of aggression.

During the study, the researchers noticed that horses became more aggressive as the feeders’ size became smaller and access to the food became more difficult. To mitigate this, researchers suggest that if horses are given a limited amount of food, it’s important to ensure enough space for each of them to eat without feeling crowded.

“Selecting the right feeding technique can extend the time horses engage in natural behaviors, reducing the incidence of chronic stress and potentially curbing the emergence of abnormal and stereotypic behaviors in the long run,” Carvalho Seabra said.

Another finding was that free-choice feeders wasted more hay than the automatic and box feeders.

Carvalho Seabra was joined in the study by colleagues Marcos Martinez do Vale and João Riccardo Dittrich, from the Department of Animal Science at the Federal University of Paraná (UFPR); Tanja Hess and Ryan Brooks from the Department of Animal Science at Colorado State University in the US; and Katherinne Maria Spercoski, from the UFPR’s Department of Biosciences in Palotina.

Effects of Different Hay Feeders, Availability of Roughage on Abnormal Behaviors and Cortisol Circadian Rhythm in Horses Kept in Dry Lots. Jéssica Carvalho Seabra, Tanja Hess, Marcos Martinez do Vale, Katherinne Maria Spercoski, Ryan Brooks, João Riccardo Dittrich. Journal of Equine Veterinary Science, Vol 130, November 2023. DOI: https://doi.org/10.1016/j.jevs.2023.104911