Forage should form the cornerstone of every horse's diet, even those with high energy demands. Horses evolved as grazers, consuming a variety of grasses, leaves, and other plants. However, as humans placed higher physical demands on work and sport horses, starch- or grain-rich concentrated feeds became popular ways to give the animals the extra energy they needed to perform. This article explores the benefits and drawbacks of forage-only diets for horses, offering insights into how to make them work effectively.
The Natural Diet of Horses
Horses evolved consuming a variety of grasses, leaves, and other plants over vast plains and steppes. They are effectively "hot-wired to chew," with a digestive system designed for near-constant intake. It’s in horses’ nature to chew, salivate, swallow, digest, and defecate practically all day and night-keeping a near-constant stream of bulk and nutrients moving through the body. By providing nutrients and energy in forage, owners give their horses the chance to have the prolonged meals their bodies are designed for. Indeed, abundant chewing and salivating is part of the repertoire of normal equid behavior and affords them better welfare.
Advantages of Forage-Only Diets
Enhanced Digestive Health
A constant supply of forage ensures a steady stream of nutrients moving through the horse's digestive system. This is crucial because horses evolved to be trickle feeders, spending 10-17 hours a day slowly grazing. Their stomachs constantly produce gastric acid, whether there’s food to digest or not. Normally as horses graze, their bicarbonate-rich saliva mixes with the long-stem forage they’re consuming and protects the sensitive stomach lining from the corrosive effects of this gastric acid. When horses are fed large, infrequent meals, the prolonged periods with an empty stomach increases their risk for developing gastric ulcers. Forage-rich diets are also better for the intestinal microbiota.
Improved Metabolism and Performance
A fiber-rich diet might also improve performance by spurring horses’ metabolism to burn more fat within the muscle. As a result, their muscle cells create less lactic acid, which is associated with fatigue.
Natural Behavior and Welfare
Horses on pasture benefit from the natural movement associated with grazing. Providing nutrients and energy in forage, owners give their horses the chance to have the prolonged meals their bodies are designed for, says Harris. "A lot of the injuries horses develop are because we mismanage them like sticking them in stalls all day," Nielsen says. "But if horses are living on pasture, they’re running around, stimulating their bones.” Like muscles, bones can become stronger from regular exercise-particularly if horses are allowed to do short sprints, he explains.
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Mental Well-being
Diets rich in forage can improve their mental, physical and overall well-being.
Types of Forage
Forage refers to the edible parts of plants that are eaten by grazing animals, like your horse. The foundation of your horse's diet can be made up of fresh forage (grass pasture), cut and dried forage (hay), or a combination of the two depending on your horse's individual needs.
Fresh Grass
Fresh grass is the closest to your horse's natural feed source, as horses evolved to spend most of the day constantly taking in small amounts of a variety of pasture plants.
Legume Hay (Alfalfa and Clover)
When cut and dried to make hay, legumes like alfalfas and clovers produce a high quality hay that can have significant health benefits when fed appropriately. Since legume hay has about 20% more calories and up to double the protein found in grass hay, it should be fed in moderation. It is usually best fed as part of the diet of performance horses or hard keepers who have an increased demand for energy. Otherwise, like fresh pasture, in excess it can contribute to obesity. Alfalfa and clover are extremely high in calcium, which can throw off the mineral balance of the diet. Horses do not regulate calcium absorption the way other species do. The extra calcium is excreted in the urine, often causing it to be cloudy in color. Too much calcium (over 2% of the diet) can eventually lead to stones or “sludge” build up in the kidneys or bladder, which may cause problems in older horses. However, the higher amounts of calcium and protein in alfalfa can act as buffers in the stomach by raising the pH. So, if fed in appropriate amounts, alfalfa may be helpful in reducing the incidence and severity of gastric ulcers . Some laminitic and metabolic horses may be sensitive to alfalfa, even when sugar and starch levels are low.
Grass Hay
Grass hay provides the minerals of fresh grass, and the long stem forage your horse needs for healthy digestion and weight maintenance, with fewer concerns about contributing to obesity. This makes it a popular choice for barns serving a variety of horses. For many horses, grass hay can be given free choice throughout the day with little management required. Hay lacks some of the vitamins and omega-3 fatty acids that are found in fresh pasture, so you’ll need to provide those key nutrients to your horse separately with fortified grain, a ration balancer, a multi-vitamin supplement, and possibly an omega-3 supplement. Not all grass hays are safe for those with Equine Metabolic Syndrome. You must check non-structural carbohydrates (NSC) to be sure the total in the diet is less than 10-12%.
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Haylage and Silage
Haylage, for example, is preserved effectively by being wrapped in an airtight binding; silage does so with even greater moisture content, enabling a beneficial fermentation process to occur, Ringmark explains. Such storage is especially appropriate for early-cut forage, which contains more moisture.
Challenges and Considerations
Nutritional Deficiencies
Despite all its benefits, forage is still rarely sufficient to meet many horses’ nutritional requirements on its own. While many horses can live well off forage alone, such diets often fail, our sources say, usually due to human error. In typical U.K. grass hays, the nutrients are sometimes insufficient even for horses in low-intensity work, Harris says. So balancers must provide sufficient-quality protein and essential amino acids, as well as vitamins, minerals, and trace elements.
Forage Quality and Analysis
Feeding the right forage in the correct amount is key to success, says Harris. Forage quality varies in multiple ways, starting with the plant species itself, she says. Grass maturity makes an important difference, as well, Ringmark says. Combined, these factors can make critical differences in a forage’s nutritional content, she explains. Because you can’t tell the make-up of your pasture grass or hay, it is vitally important to have your hay and forages tested.
Dry Matter Content
The way the forage was preserved also affects the amount of dry matter-a critical point, given most equids should be eating at least 1.5% of their body weight every day in dry matter. Dry matter is not the same thing as the total weight of the preserved forage fed to a horse. Baled hay is usually 85-90% dry matter, meaning the rest of the weight is moisture (even if it feels completely dry). But haylage varies dramatically in its dry matter content; while it’s generally 60-75% dry matter, it can range from 50% to nearly 90%. In other words, there’s almost always more dry matter in hay than in haylage, so getting to that 1.5% body weight in dry matter might require more haylage than hay. Hay baled with more than 15% moisture (less than 85% dry matter) is likely to become moldy, which can threaten horses’ respiratory as well as general health, says Harris. "If you want to feed hay to horses with respiratory issues in particular, it may be advantageous to steam first-although you should always start with as good, hygienic, quality hay as possible," she says.
Weight Management
Of course, people can try managing their horses’ weight by giving them more or less hay, Harris says. But it’s better to avoid cutting the amount fed, which defeats an important point about forage-rich diets: spending much of the day chewing and swallowing. And it might not even be possible to sufficiently increase the intake of mediocre hay for horses with high energy needs.
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Gradual Transition
Transitioning a horse to a forage-based lifestyle is a gradual process that should be done carefully to avoid digestive issues. Introduce changes slowly to allow the horse’s digestive system to adapt. Gradually decrease the number of concentrates while increasing the amount of forage.
Monitoring and Adjustment
Keep a close eye on the horse’s weight and body condition. And don’t forget to take into account any special needs of the horse. This can include-but is not only referencing-age, activity level or health conditions. Some horses may require additional supplements to meet their nutritional needs. Observe the horse for any changes in behavior, such as signs of discomfort or colic. Remember that every horse is unique, and individual needs may vary. People must also recognize the signs of failure, adds Harris. “If you don’t provide horses with enough energy, they’ll be thin and often lack energy,” she says. “If you provide them with too much energy, they’ll be fat or very excitable or both. Other factors, such as training or underlying pain, can also cause or contribute to body condition and muscle-associated issues, she says.
The Risk of Rapid Changes in Forage
Today, however, owners often change their horse's forage rapidly, whether by moving to a new barn or buying hay from a different farmer. Unfortunately, rapid changes in forage are risky for horse health. Sudden changes in hay (including switching to a new cut from the same field) can cause a 10X increase in your horse's risk of colic. Digestive disruption can contribute to everything from mild diarrhea to laminitis and founder. So, make changes to your horse's diet as slowly as possible.
Supplementation
Fortunately, commercial feed balancers offer a good blend for topping off forage, says Ringmark. “We usually get a surplus of the minerals, because we already have them in the forage,” she says. “But it’s never been way out of range. Ringmark’s study horses get enough protein, calcium, magnesium, and phosphorus in their Swedish haylage, she says.
Practical Tips for Implementing a Forage-Only Diet
- Consult with Experts: Work with equine nutritionists and veterinarians to assess your horse's specific needs.
- Analyze Forage: Regularly test your hay and pasture to understand its nutritional content.
- Feed by Weight: Aim to feed at least 1.5-2% of your horse’s bodyweight in forage every day.
- Provide Supplements: Use balancers to address any nutritional gaps in the forage.
- Monitor Health: Regularly assess your horse’s body condition, energy levels, and overall health.
- Ensure Constant Access: Keep forage in front of your horse for as much of the day as you can.
Additional Considerations
Mixing Grass and Legume Hay
It's certainly fine to mix grass and legume hay, but if you do, we recommend mixing in both at every serving rather than alternating between meals.
Weighing Hay
You'll notice that when it comes to measuring out your horse's forage, we're speaking in l-b-s, not f-l-a-k-e-s. That's because all bales are not created equal. Even if you're just getting a new cut of hay from the same field you used earlier this year, the density of the bales and flakes might have changed. That's why it’s always recommended to weigh your hay whenever you get a new cut. One preferred method is to use a hanging scale (like the kind at the grocery store). Whenever you get a new delivery of hay, have someone in the barn weigh a few flakes from several different bales throughout the load, and use those results to calculate an average.