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Does A Horse Need Grain?

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With all the feeding options available for horse owners, the thought of what to feed your horse can intimidating! While some people prefer to let their animals graze year-round on fresh pasture, others supplement with hay, while many horse owners also feed some kind of grain or sweet feed.

Black warmblood horse in grain field

Some will also point to wild horses and their solely forage diets. With all the feeding options out there, do horses need grain?

Does a horse need grain? Some horses do need grain in their diets, while most are just fine without it. The top reasons a horse would need grain are:

  1. They are in high-intensity training (like racing).
  2. They are nursing a growing foal.
  3. Forage is not meeting their energy requirements.

When Should Horses Be Fed Grain?

Sometimes, horses do need to be fed grain in order to keep them healthy. To figure out if a horse needs grain, you should consider whether your horse needs additional calories, minerals and protein, as well as a few other variables.

Just like people, individual horses have different needs. Their size, activity level and resting metabolic rate all help determine just how much they need to eat.

Horses eat around 2% of their body weight on a daily basis. Assuming the average horse weighs about 1,000 pounds, that means they should be eating about 20 pounds of food per day. If they’re more active and burning off calories through exercise, they can eat up to 40 pounds each day.

female holding feeds with corn, barley, oats grain to feed the brown horse at stables

Hay flakes tend to weigh only three to eight pounds each, meaning higher-performing horses probably can’t and won’t eat enough hay to meet their needs.

If they’re expending enough calories that they need to increase their dietary intake in order to maintain their weight, they will need a more efficient way of getting those calories into their systems. That probably means supplementing their diets with grain.

Compared to hay, grain provides about 1.5 times more energy per pound. It is also much smaller by volume, making consumption of those extra calories easier for a horse.

Hay, depending on the type, may also not include all the necessary nutrients and minerals, specifically calcium and phosphorous, a horse may need. This is especially important if a horse has digestive problems that make breaking down food to get the necessary nutrients difficult.

Horse digestive systems naturally break down and absorb structural carbohydrates from foraged food in their hindgut. This happens through a special type of fermentation.

While a healthy hindgut can help your horse get around 70% of its daily energy requirements, including protein, fats, vitamins, and minerals, from a good forage mix, some horses need a little more help.

If a horse naturally has trouble breaking down food, then a strictly grass and hay diet won’t be enough for them. Horses that are notoriously hard keepers (drop weight fast), such as Thoroughbreds, nursing broodmares, highly active horses, or horses with the aforementioned digestive problems will need grain in their diets in order to meet their caloric and nutritional needs.

Grain is easier for digestive systems to break down, as there are mainly simple carbohydrates in starchy feeds (like oats, corn feed and barley). These are digested in the foregut and absorbed into the system more easily.

Protein, too, is a factor in deciding the makeup of a horse’s diet. Adult horses should be consuming enough protein to account for about 8% of their diet each day, with high-performing horses requiring more. (source) Hay tends to have a 7% – 10% protein amount, so if a horse is working more, they will need grain to provide additional protein.

Horses who are not turned out on pasture the majority of the day, even if they aren’t hard keepers, will probably need some grain. Keep in mind, too, this can fluctuate with season. During winter months, grass will not be as plentiful and turnout time will likely be limited, meaning horses may need more grain than usual,- or to start eating grain at all.

When Should Horses Not Be Fed Grain?

One of the problems associated with grains and their high simple carbohydrate content is that diets high in this feed can lead to digestive issues such as stomach ulcers and even colic. Because of this, grain should be regulated. A good rule of thumb is for a horse’s diet to contain no more than 25% grain.

Also, age is a big factor. Senior horses who are barely ridden (if ever) shouldn’t have grain, as it will introduce too many carbohydrates into their systems and cause digestive health issues, weight gain, etc.

Horses on high quality pasture for most of the day will not need extra grain. Good grass will provide most, if not all, the nutrients and calories they need. Horses evolved to be roughage eaters, so their bodies are naturally designed to subsist off of quality grasses.

The bottom line is that unless a horse is a high-level athlete or a traditionally hard keeper, and if they have access to pasture almost all day, then a diet that is solely high quality grass and/or hay should be sufficient.

What Are Commonly Fed Grains?

The top three grains fed to horses are oats, barley and wheat. (source) Of the three, oats are the most popular – and safest thanks to a good fiber content (around 13%). They have a higher bulk to nutrition ratio, meaning horses need to eat more, which makes it harder for them to accidentally overeat in calories and colic or founder.

Brown horse eating barley and bread

Barley is similar to oats but has a lower fiber content and is classified as a “heavy” feed, meaning its more energy-dense and weighs more by volume. Corn has the highest energy density and the highest amount of carbohydrates, making it easy for a horse to overdose on starch. It’s a good option, though, for high energy and highly worked horses.

There are also several commercial feeds specifically designed for horses that combine different grains into palatable pellets. These feeds can be made with the perfect balance of proteins, fiber, and carbohydrates to meet different horses’ exact needs. Many also have vitamin and minerals added, so they can be a convenient choice.

Do Horses Need Grain in the Winter?

When it comes to winter, the chance that a horse may need to be eating grain increases. When grasses stop growing and pasture quality lessens, a horse may not be getting enough to eat on pasture alone.

A pair of brown horses on a cold winter

Even these horses who may not need grain from spring to fall will need something extra. Hay, while a good food source, is not enough to make up the entirety of a horse’s calories and nutrients through an entire cold season. While a horse is removed from pasture in the winter, grain is often added into the diet.

Since horses have notoriously fickle digestive systems, though, the introduction of grain shouldn’t be sudden. Incorporate grain slowly, starting before the winter when horses are still eating grass a lot. Gradually increase the amount of grain so by the time winter rolls around and they’re off pasture, their bodies are used to the simple carbs.

Even if a horse’s winter diet is mostly hay rather than grass, grain should still make up 25% or less of their daily total foods.

How Do You Know How Much Grain to Feed Horses? How Much Is Too Much?

When it’s time to figure out how much grain to feed a horse, you should take into account their size, weight, age and metabolism, as well as their current or planned future workload.

Horse Feed Grain

One excellent resource is your local feed company. They’ll be able to answer any questions you may have or put you in contact with an equine nutritionist.

There are also handy online tools that can help you dial in on the specifics for your horse. Horse feeding calculators (like this one from Purina) take into account the above factors and do the math for you.

Heavily worked horses with high metabolisms may need up to 5 – 10 pounds of grain a day, whereas lightly worked horses may require anywhere from none to three pounds. (source)

When it comes to grain, remember the “less is more rule” and that you can always adjust up, so it’s better to start with smaller amounts.

As you incorporate grain into a horse’s diet, keep an eye on them for behavior or physical changes that can indicate something wrong with digestion. Grain is also best when its spread across several smaller meals throughout the day rather than all at once. (source)

It’s important to not overfeed grain, and what constitutes too much for one horse may not be the same for another. That’s why it’s so important to consult an equine nutritionist or a feed expert before making changes to your horse’s diet.

When Should You Take Your Horse off Grain?

If a horse is having digestive problems, noticeable behavior changes, or has gained a lot of weight too quickly, it may be a good idea to take them off grain. Also, as horses age, they need less and less. Senior horses who are not worked need no grain at all, so as your horse ages into retirement, they can come off the grain.

Black and brown horses eating hay

Also, if you are transitioning your horse to being on quality pasture all day or most of the day, you can most likely remove all or some grain from its diet.