Why cereal grains for horses should ALWAYS be cooked

Cereal grains such as oats, barley, triticale, corn, rice, rye, sorghum and wheat are commonplace in horse diets. When fed well, cereal grains form a valuable component of many horse’s rations.

But fed improperly, and they will cause large shifts in your horse’s gut microbial population, causing dysbiosis and a host of serious health and behavioural issues. Issues that can be so severe they will end the performance career of your horse and in the worst cases, even lead to death!

So feeding grains in a way that is safe and beneficial to your horse is crucial if you want a healthy, calm, happy horse to partner with.

Selecting safe and digestible grain based feed, however, can be confusing, with uncooked grains like whole, cracked and crushed grains being available as well as cooked grains like extruded, micronised, steam rolled/steam flaked and pelleted grains.

Let’s look at which form of grain is best for your horse, cooked or uncooked?

Spolier alert: Just in case your horse calls and you don’t get the chance to read further… you should ALWAYS feed cooked grains to horses!

Why do we cook grains?

Grains are fed primarily as a source of energy in a horse’s diet.

And that energy is derived mainly from the white starch found in the centre of the grain. Starch is just a long string of glucose molecules all joined together.

For your horse to extract the energy from the starch it must be digested into single glucose molecules for absorption. Starch is cut up into glucose by starch digesting enzymes, which are like tiny pairs of scissors, whose job, is to cut up (digest) starch in the small intestine.

But digesting the starch into glucose to extract the energy from grain is not easy for the horse because the starch is “packaged” within the grain in a way that makes it difficult for the horse’s enzymes to get to.

We cook grains to make access to the starch a whole lot easier for the horse. And in doing this, we increase digestion and reduce the MANY negative effects cereal grains can have on your horse’s health.

To understand this a little more, let’s take a look at how starch is packaged inside cereal grains and why this makes it hard for your horse to digest the starch.

How is starch packaged?

If you break open a single grain of barley, corn or oats you will see, inside the grain, ‘white stuff’. This stuff is called the ‘starch endosperm’ and this is where grains store their starch.

Starch, as I mentioned, is simply many glucose molecules all bonded together in long strings. Sometimes they are just straight strings of glucose. And other times they have many branches.

These strings are then tightly bundled up into starch granules. And the starch granules are then embedded amongst protein in a structure known as the protein matrix (Figure 1).

Figure 1: A scanning electron micrograph of the middle of a barley grain showing the starch granules embedded within the protein matrix. The starch granules are the large round objects. And the protein structures are the small round objects surrounding the starch.

The starch granules, embedded in the protein, are then encased within individual endosperm cells and protected by a cell wall (Figure 2).

Then hundreds of thousands of these tiny little starch containing cells are packed tightly within the grain’s starchy endosperm (the white bit found in the middle of a grain).

The starchy endosperm itself is then protected by the ‘aleurone layer’ and finally the entire structure is covered by the seed coat (Figure 2).

This gives the starch 4 layers of protection from the outside world! And 4 layers of protection from your horse’s starch digesting enzymes!!

From the plant’s perspective, all of this packaging is absolutely critical for its survival and it is beautifully designed to protect the plant embryo and its stored sources of energy (starch) and protein to ensure it will be able to grow and survive for the first few days following germination.

Figure 2: The location of starch granules (stained black) within the endosperm cells of barley grain surrounded by the protein matrix (stained green) and protected by the aleurone layer and seed coat.

So, the packaging is clever and essential from the plant’s perspective! In fact, this packaging was actually specifically designed to allow a grain to pass through the gastrointestinal tract of an animal undamaged so it may germinate when it is excreted in the manure.

HOWEVER, for the horse, all of this packaging is just a nuisance and prevents the horse from being able to get to and digest the starch in their small intestine so they can extract the energy from the grain.

And worse, it means that most of the starch ends up being delivered to the hindgut where it is rapidly fermented causing microbial dysbiosis, hindgut acidosis, leaky gut and all of the health and behavioural issues associated with these conditions!

Enter coked grains…

It has been recognised for hundreds of years that feeding cereal grains to horses can ‘make them sick’. And, we have known for several decades now that to safely eat and effectively digest cereal grains, horses need some help.

That help comes in the form of ‘cooking’ where some combination of heat, moisture and pressure are used to literally cook the grains.

Cooking grains using processes like extrusion, micronizing and steam flaking helps your horse’s enzymes to get through all of those protective structures around the grain starch, so that they can physically get to and cut up the starch.

How does cooking help?

When grains are cooked using a combination of heat, moisture, pressure PLUS some form of physical process like rolling or grinding, the entire structure of the grain is disrupted.

To start, during the physical processes of grinding or rolling, the wrapping of the grain, the seed coat and aleurone layer, are broken apart. And the endosperm cell walls and protein matrix are opened up.

In their broken up and disrupted state, these structures are no longer able to protect the starch granules. But this is only a small part of the story…

The heat, moisture and pressure used during cooking turns the ordered and tightly packed structure of the starch granule itself, into an open and vulnerable structure in a process known as gelatinisation.

Gelatinized starch is very easy for your horse’s starch digesting enzymes to cut into single glucose pieces.

So cooking helps your horse’s enzymes to physically gain access to starch AND makes the previously tightly bundled starch, open and susceptible to digestion.

What about cracked or ground grains?

Cracking, crushing or grinding grains is the same process as chewing and only changes the physical structure of the grain… breaking the seed coat, aleurone layer and some of the endosperm cell walls and protein matrix up.

BUT, the starch granule structure remains completely intact, meaning only small improvements to starch digestion will be made because even though access to the starch is made easier by cracking or grinding, the starch itself is still tightly bundled up and not able to be cut up and digested by your horse’s enzymes.

Research conducted in horses showed that cracking corn only improved its digestibility in the small intestine of the horse by 1%.

So while physical processing can get an enzyme through the front doors it leaves the enzymes without actual access to the starch. In short, they’re no better than whole grains and should not be fed.

Does soaking grains help?

Soaking grains simply makes them easier to chew, so soaking will help the horse to break the seed coat and aleurone layer barriers.

But, soaking does nothing to disrupt the endosperm cell wall, protein matrix or starch granule structure, so, like cracking grains, soaking does not help to improve starch digestion.

What happens if you feed uncooked grains?

Starch from uncooked grains will remain largely undigested as it passes through the small intestine and will eventually be delivered to the hindgut.

This is where the trouble begins. The bacteria in the hindgut do not face the same barriers to starch digestion as the enzymes in the small intestine, and they are able to reach and rapidly ferment the starch contained in uncooked grains.

This rapid fermentation of starch causes excessive production of acids, which accumulate in the hindgut and lower the hindgut pH (the hindgut contents become acidic). PLUS your horse’s hindgut microbial balance will shift, with the ‘bad’ starch and sugar fermenters taking over and literally killing off your horse’s ‘good’ fibre fermenting microbes!

Low pH and microbial dysbiosis in the horse’s hindgut causes a multitude of performance issues, diseases and behavioural disturbances including leaky gut, laminitis, colic, endotoxaemia, systemic acidosis, systemic inflammation, compromised immune function, changes in behavior toward spooky, anxious, reactive behaviour, poor performance, slow recoveries, reduced fibre fermentation, poor appetite, weight loss, wood chewing and the eating of bedding as well as deficiencies in the B-group vitamins (including biotin) and vitamin K.

Excessive starch fermentation in your horse’s hindgut is a physiological disaster for your horse and MUST be avoided!

What about oats?

The general consensus is that oats can be fed unprocessed. As it is a larger grain, horses are capable of chewing the grain enough to break its seed coat, removing the need for physical processing.

Studies have also found that oat starch is far easier to digest than corn or barley starch in an uncooked form. AND, if the starch does make it to the hindgut, research seems to show that it doesn’t ferment in the same way other grain starches ferment, and it appears to cause less damage.

So oats can be fed whole and uncooked. I would still personally prefer to use steam flaked over whole oats.

Also keep in mind, whether oats can be fed unprocessed needs to be decided on a horse by horse basis. Observe your horse’s manure closely when you are feeding them oats. If you observe whole oat grains in their manure, whole oats is not a suitable feed for this horse.

Feed cooked grains!

If you want or need to feed cereal grains to your horse, they MUST always be fed cooked, with the exception of oats for some horses. If you feed uncooked cereal grains, your horse will get little benefit from them AND they have a good chance of causing weight loss, poor performance, slow recoveries, serious disease and behavioural problems.

Remember, the reason you feed cereal grains is to provide your horse with a source of energy. Most of this energy is held within the grain’s starch. Feeding cooked grains to your horse means they will be able to properly digest that starch and gain the full energy benefits of the grains you are feeding! AND they will stay healthy, calm and happy in the process with the energy they need to perform at their best!