Why You Should Reconsider Forage Slow-Feeders

By Kim Hallin

Horses NEED Free-Access to Forage
It’s commonly known that wild horses graze for at least 13-15 hours per day and that the equine digestive tract is specifically designed to digest small amounts of a wide variety of high-fibrous feedstuff on an almost continuous basis. To embrace husbandry practices that work in opposition to the horse’s natural digestive system is asking for health problems.

As part of their natural digestive process, horses constantly produce stomach acid.  This acid production is not triggered when the horse eats but is continual, even when the horse is not eating! Meanwhile, horses only salivate when they are chewing.  Horses that forage continuously can produce up to 7 or 8 gallons of saliva per day! This saliva serves as an acid buffer, neutralizing the hydrochloric acid in the stomach, as well as lubricating the food.

Unfortunately for most domestic horses, this constant production of acid combined with human-induced restriction of forage (which also limits saliva production) creates tremendous health concerns. If a horse is not chewing enough throughout the day to produce adequate buffering saliva, the resulting acid build up can present itself as ulcers, cribbing, colic, choke, gorging, cribbing, laminitis, stall vices and other behavioral problems.

Gut Motility is Dependent on Mobility
In the wild, horses travel a minimum of 10 miles per day, sometimes up to 30 miles per day.  Most of this is slow/casual travel between favorite grazing areas and watering holes.  Wild horses can also go anywhere from one to three days without water.  While this thought may be terrifying for those of us who care for colic-prone domestic horses, the constant gentle exercise and slow intake of a wide variety of fibrous materials (including grasses, weeds, fruits, vegetables, seeds, sticks and twigs) of wild horses keep them at very low risk for colic.

On average, domestic pastured horses only initiate 4 miles of movement per day, regardless of the size of the enclosure they live in.  Even horses living on pastures of more than 30 acres in size still average only 4.5 miles of movement per day!  Meanwhile, stalled horses given turnout time in a yard average only 0.6 miles of free daily movement. Given this wide disparity between wild horse movement and domestic horse movement, it’s logical to conclude that many common health issues – and especially the high incidence of colic from impactions of hay and/or sand – are a direct result of the domestic horse’s lack of physical movement. Our traditional practice of exercising domestic horses several times per week, or even daily for short periods, does little to address this overall predicament. It is only constant, gentle physical movement that ensures consistent internal movement of feedstuff through the hindgut.

The low rates of daily movement for domestic horses combined with the high nutritional values of most commercially harvested hay also means that if we are not careful in domestic settings, offering horses free access to hay can result in obesity and metabolic disorders.  Domestic horses often stand in one place (i.e. confined to a stall or parked in front of a stationary hay pile/feeder) for many hours, eating large volumes of high-quality forage simply because this is what we place in front of them. It is instinctual for a horse to eat as much as it can when food is available because in the wild they never know when food sources will become scarce again.

The Stress Factor
Not only is forage restriction dangerous for horses due to excessive acid production but it is also incredibly stressful for a horse to be denied its natural instinct to graze. This stress causes the release of the hormone cortisol, which in turn leads to elevated insulin. When insulin is high, it tells the body to store fat. You see where this is going…

Because of these interwoven dynamics, some horses that have been on a restricted-forage diet will gain weight very rapidly when suddenly given free-access to hay. The reason has to do with the sluggish metabolic rate they’ve developed over time. When forage is parceled out only a few times a day, the horse’s body responds by going into “survival mode,” where his metabolic rate significantly slows down in an attempt to conserve body fat. This creates a cycle of ever-increasing obesity. This cycle can be reversed, but only with adequate movement/exercise and permanent removal of the hormonal fat-storing response that forage restriction creates. And, it takes time for the metabolic system to return to a more normal state of functioning.  Most horse owners give up much too soon when attempting to rehabilitate a metabolically-compromised horse.

Slow Feeders are the Best Solution Currently Available
Slow hay-feeders can provide an effective solution to these challenges for many horses. When used strategically to enhance natural herd behavior, slow feeders are also an excellent way to do reduce stress and increase daily movement. As their name suggests, these feeders slow down the rate of consumption by providing access to the hay only through small openings. When slow feeders are kept full, they allow the horse to graze whenever he wants, thereby eventually prompting the horse to eat less at one time.

The primary benefits of slow-feeders are three-fold:

1) They slow the rate of consumption, better mimicking the natural “trickle feeding” requirements of the horse’s digestive system

2) They require the horse to “work” a little harder seeking out feedstuff and pulling the hay through the holes of the slow feeder.  This mental stimulation helps prevent boredom and stress.

3) When two or more slow feeders are placed strategically in a herd environment, horses will naturally migrate back and forth between feeders creating some additional gentle movement throughout the day – enough to help keep feedstuff flowing internally in the gut.

How well do slow feeders really work at slowing the rate of consumption?
A study conducted by the University of Minnesota Extension looked at the effects of feeding grass hay using hay nets with various size openings.  Below is a summary of their findings:

Hay Distribution Consumption rate
per hour
Time to consume 1% of body weight
Free Choice on Floor
(no net)
3.3 lbs 3.2 hours
Hay net with
6 inch openings
2.9 lbs 3.4 hours
Hay net with
1.75 inch openings
2.4 lbs 5 hours
Hay net with
1 inch openings
1.9 lbs 6.5 hours

The results of this study can be very helpful to horse owners who want to make the best choice when selecting slow-feeders.  For example, if hay nets with small (1 inch) or medium (1.75 inch) holes are used for twice daily feedings at 1% of body weight per feeding, the anticipated amount of time the horse will spend foraging will be 10-13 hours per day – which pretty closely mimics a horse’s natural grazing behavior!  Therefore, small and medium hay nets represent a very simple and affordable management tool for extending foraging time while controlling the volume of hay provided.  It will also considerably extend the amount of time a full bale of hay will last when fed free-choice.

The best approach is feeding on the ground 
Chewing with the head low is more in line with the horse’s natural physiology, creating even pressure on the teeth and allowing the jaw bone to move freely in all directions. Furthermore, the muscles, joints, tendons, ligaments and bone structure are not stressed when horses can grab hay in a straight downward motion. Eating with their heads down also protects their eyes and respiratory tract against mold spores and dust and provides for better nasal drainage.

Summary of Benefits to Horse and Human

Benefits of using slow-feeders for the horse:

  • Slows down digestion/consumption
  • Bronchial & inhalant allergies are reduced significantly
  • Mimics grazing action
  • Keeps insulin levels even
  • Cribbing horses are helped
  • Helps with the prevention of ulcers and colic
  • Obese horses lose weight and thin horses gain weight
  • Horses are never without fiber intake

Benefits of using slow-feeders to the human:

  • Much less wasted hay to clean up
  • Saves hours of labor on feeding
  • Horses are always ready to ride or work
  • No more rushing home to feed

Of course, we must use common sense when picking the best slow feeder (net, bag or box) for our horse! Be sure there are no loose ropes or strings that a horse could get caught up into. Horses with shoes should only be exposed to slow feeders that are in a box or a cover so that the horseshoes can never come in contact with a net or grate to get tangled/caught in. No halters either. Some types of slow feeders (particularly those with metal grates or bags with wide webbing like the one pictured here) can cause unnatural wear on the front teeth.  Regular dental exams are essential to ensure no harm is being done to the teeth. There are a wide variety of slow-feeders on the market today so look around and see what system works best for your situation!

How to start
Use at least two feeders for one-to-two horses and place them as far apart as possible. With more horses, use more feeding stations so that every horse always has access to a safe and comfortable place to eat. Even if your horse is in a stall or small paddock, place one slow-feeder on either end of the area. Larger slow-feeders can accommodate two or possibly three horses at a time, but it is preferable to have more feeders to encourage movement, satisfy the horse’s natural curiosity, and minimize squabbles among herd members.

Gradually allow your horse to become accustomed to this method of feeding by placing some hay in the feeder as well as some that is loose on the ground next to the feeder.  After a few days, most horses will get the hang of using the slow-feeder. Some take longer, so don’t force the issue; let your horse get used to it at his own pace.

If your feeder contains a top net or grate, leave the top off for a few days as your horse becomes familiar with lowering his head inside the feeder. Once you add the net/grate, pull hay through the openings to help get him started.

Supervise your horse during this transition period, watching for signs of frustration. Frustration is a form of stress and should be avoided if possible.

Types of slow-feeders

Traditional hay nets are not the same as slow-feeder nets.  Hay nets typically have very large openings. Slow-feeder nets provide openings that are much smaller. We recommend 1.5 to 1.75 inches for a full-sized horse; anything smaller may cause undo frustration. With excessively small holes fatigue can also set in, causing the horse to stop eating.

It is best to purchase your slow feeder from a reputable manufacturer rather than trying to make your own. Cheaper fabrics and materials can unravel and break, potentially damaging teeth and worse, tragically leading to colic if your horse swallows fibers. Commercial products are made from heavy duty fabrics that resist tearing and fraying, and provide safety features as well as customer support.

Advantages of slow-feeder nets

  • They come in a variety of sizes that can hold a few flakes, a whole bale, or even an entire round bale.
  • There is flexibility in mounting them. Many can be attached to a wall, tree, or sturdy post at a low level. The best ones are designed to be on the ground, allowing the horse to eat in a more natural position.
  • Free-standing hay nets allow horses to roll, carry or move them – all of which encourages higher rates of natural movement as well as relief from boredom.  High quality nets like those made by Hay Burners Equine LLC, easily stand up to this type of playful use!

Potential problems:

  • If the horse is shod, nets must be secured within a bin; you can also hang them high enough to prevent a shoe or nail from snagging on to the netting but this will create an awkward eating position.
  • If laid on the ground, nets must either be totally loose or securely mounted in a way that prevents the horse from getting a foot or his head caught underneath the feeder.
  • If dangled from a tree or post, nets can quickly become a source of frustration as they sway with every attempt to get a bite. This can defeat your purpose in regulating consumption. Furthermore, if the horse were to rear near a feeder hanging from a tree or placed high in a stall, he could trap a hoof.
  • Smaller slow feeder nets need to be refilled frequently, and this can be time-consuming. Horses who run out of hay (even for 10 minutes) will never get the message that hay is always there and will not self-regulate. For this reason, whole or half-bale nets are highly recommended.

Hard slow-feeders
The best hard feeders are made of sturdy plastic or hard rubber that will not crack in very hot or cold temperatures and can withstand the abuse of being kicked or stepped on. Avoid wooden feeders that are not as sturdy, and especially those made with treated lumber. You might be tempted to build your own by placing a steel grid on top or on open sides of a container. This can create several hazards:

  • There is high potential for sharp edges.
  • Clips can get caught on halters or catch an ear or eyelid.
  • Grids can tilt.
  • Shod horses can trap a foot on the metal openings.
  • Metal grates can damage teeth; horses can even get a tooth caught in this type of grid.
  • Grated vertical sides force the horse to turn his head sideways, which leads to neck strain.

Quality hard slow-feeders offer several advantages:

  • They allow the horse to eat with their heads in a natural position.
  • They are easy to fill with hay.
  • Feeding can be shared with more than one horse.
  • Dust and dirt tends to flow to the bottom.

We hope you have found the information in this article helpful as you consider your own horse husbandry practices and plan for future improvements.  Here’s to healthy, happy, NATURAL horse keeping!

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