Focus on Forage

Build your horse's ideal diet from the ground up.

Updated February 8, 2024
flakes of hay in barn aisle

When most riders and owners think about feeding their horse, their mind often jumps first to grain. Think about switching barns, going to a horse show, or trying a new feed store—you often think, "I wonder if they'll have my brand."

Perhaps it's because owners are often involved in selecting their horse's grain, while hay is just sort of "there." Or maybe it's because grain is more similar to kibble, so we think of it as being the same as feeding our dogs. Perhaps more likely, it's because there are so many companies advertising grain that it's always top of mind.

While grain may be a priority for owners, it's forage that should be the foundation of every horse's diet.

What is Forage?

close up on bale of hay

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.

Finding the Best Type of Forage for Your Horse

We will explain the most common types of forage and the pros and cons of each.

Fresh Grass

Your horse evolved to spend most of the day constantly taking in small amounts of a variety of pasture plants, so fresh grass is the closest to your horse's natural feed source. It also has key minerals, vitamins, and essential fatty acids that make it an ideal feed source.

However, fresh grass in your horse’s turnout is also very high in simple carbohydrates (sugars and starches), meaning that it may not be the best choice for easy keepers (horses that are overweight), those prone to founder, or horses with endocrine, metabolic, or other disorders.

Acres of fresh pasture are hard to come by, so most horses need their diet supplemented with baled hay or another form of forage to meet their daily requirements.

Legume Hay

flake of alfalfa hay

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 [1].

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%.

Can You Feed a Combination of 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. This will provide the most consistent digestive experience for your horse.

Video on the Benefits of Grass and Legume Hays for Horses

Depending on your horse’s individual needs, he may also benefit from other options like alternative forms of hay and forage substitutes.

How Much Forage Does My Horse Need?

Horse eating hay from ground in the stall

We refer to forage as the foundation of your horse's diet because, at a base level, horses should be eating 1.5–2% of their bodyweight in forage every day. For a 1,000 lb horse, that's at least 15–20 lbs of forage per day.

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.

From there, it’s just a bit of simple math. For example, if your horse weighs 1,000 lbs and you weigh your hay and find that the average flake is about two pounds, you'd need to feed 7.5–10 flakes over the course of the day to meet your horse's 1.5–2% bodyweight requirement of 15–20 lbs of forage per day.

Making Gradual Changes in Forage is Key

woman getting a flake of hay from loft in barn

Consistency is the name of the game when it comes to feeding for digestive health. Many years ago, horses were limited to the distance they could travel on their own four hooves. Therefore, they experienced changes in pastures very gradually, giving their digestive systems time to adapt.

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. You may also want to consider providing daily digestive support since many changes in hay can be unavoidable.

Provide Forage Throughout the Day

horse eating hay in the paddock

You might have noticed earlier that we described feeding your hay "over the course of the day," rather than saying "each meal." That's because horses weren't designed to eat large, infrequent meals. That's something humans have introduced into their lives, because it's how our meals are traditionally structured.

Eating large, infrequent meals doesn't cause problems for us humans because our stomachs only produce gastric acid once we start eating. When it comes to your horse, he evolved to be a trickle feeder, spending most of his day (10–17 hours) slowly grazing. As a result, his stomach is constantly producing gastric acid, whether there’s food to digest or not. When paired with infrequent meals, this is a recipe for stomach troubles.

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. But the longer a horse’s stomach sits empty and unprotected in between large meals, the more at risk he is for developing gastric ulcers.

The lower portion of the stomach (where gastric acid is produced) is lined with glandular mucosa. Not only is this lining built to withstand the harsh effects of stomach acid, but it also produces bicarbonate and mucus as an added layer of protection. The upper portion of the stomach is lined with non-glandular mucosa, which is less able to hold up to acid exposure and does not produce protective material like mucus and bicarb. This makes it that much more important to feed small meals frequently or allow grazing.

Provide Daily Support for Gastric Health

A horse eating out of a hay net hanging on a trailer

In an ideal world, your horse’s ears would always be forward and his tummy would always be full. But we know not every barn can provide free-choice hay throughout the day, and many horses cannot have unrestricted hay due to weight management concerns.

But if your horse must spend long periods with an empty stomach, it’s your responsibility to support a healthy stomach, whether that’s with a gastric health supplement, a small-hole hay net to keep forage in front of your horse longer, reducing the amount of grain he gets, or some combination of those options. Keep reading to learn where grain fits into your horse’s diet (if at all!).

Putting it All Together

Smart management of your horse’s forage intake will have wide-ranging impacts on his health — from weight and overall body condition to supporting healthy, normal functions throughout his delicate digestive system. That’s why it’s worth the investment of time, energy, and attention to focus on forage first.

Key Takeaways

  1. Forage is the foundation of your horse’s diet.
  2. Aim to feed at least 1.5–2% of your horse’s bodyweight in forage every day.
  3. Make changes as gradually as possible and consider providing daily digestive support.
  4. Keep forage in front of your horse for as much of the day as you can.

Additional Horse Owner Resources

Evidence-Based References

  1. Lybbert, T. & Gibbs, P. & Cohen, N.D. & Scott, B. & Sigler, D.. (2007). Feeding alfalfa hay to exercising horses reduces the severity of gastric squamous ulceration. Proc AAEP, Orlando, Florida, USA. 53. 525-526.
  2. Nutrient Requirements of Horses, sixth revised edition. 2007. National Research Council. National Academies Presses. Washington, D.C.

SmartPak strongly encourages you to consult your veterinarian regarding specific questions about your horse's health. This information is not intended to diagnose or treat any disease, and is purely educational.