Equine Gut Health

Equine Gut Health Equine Gut Health is an educational page focused on understanding the gut microbiome. Using science and real-world microbiome insights.
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Exploring equine digestion and gut microbiome & links to health, disease risk, behaviour, and performance. Equine Gut Health is an educational page focused on understanding the horse from the inside out. We explore the equine digestive system and gut microbiome, and how it influences health, disease risk, behaviour, and performance. Using science and real-world microbiome insights, we explain why

modern feeding and management don’t always deliver expected results — and how the gut holds many of the missing answers.

Low calorie doesn’t always mean low impact on the gutMany “good doer” feeds are marketed around weight control, sugar an...
06/05/2026

Low calorie doesn’t always mean low impact on the gut

Many “good doer” feeds are marketed around weight control, sugar and starch reduction — which sounds ideal for horses prone to weight gain, laminitis risk, or metabolic issues.

But from a microbiome perspective, it’s worth looking beyond the front label.

This type of formulation is typically built around:
Processed fibre sources (straw, oat hulls, soya hulls, beet pulp, wheatfeed)
Fortification layers (minerals, immune/hoof support, additives)
Palatability enhancers and functional sugars (including fructose/isomaltulose)

So what does that mean for the hindgut?

Potential positives:
Higher fibre intake can support fermentation and short-chain fatty acid production
Lower starch reduces the risk of rapid starch overflow into the hindgut
Beet pulp can be a useful fermentable fibre source for many horses

Potential considerations:
Highly processed fibre blends are not the same as diverse forage
Multiple ingredient fractions can create a “nutritionally complete” feed while still offering relatively poor microbial diversity support
Sweeteners, flavour enhancers and functional sugars may improve intake, but don’t necessarily improve microbiome resilience
Bucket volume can create a false sense of dietary adequacy while forage quality remains unchanged

A horse’s microbiome doesn’t read marketing claims.

The healthiest hindgut ecosystems are generally built on:
Forage diversity
Fibre complexity from whole ingredients
Consistency
Minimal unnecessary dietary complexity

A bucket feed may help manage calories, but it should never become the foundation of gut health.

Ask not just “is it low calorie?” but “what microbial environment is this actually feeding?”

When a horse is “fine”… but not quite rightAt this time of year, a lot of horses don’t show obvious problems. They’re no...
04/05/2026

When a horse is “fine”… but not quite right

At this time of year, a lot of horses don’t show obvious problems. They’re not lame, not unwell… and yet owners often say:
“Something just isn’t quite right.”
It might be slightly looser droppings, a bit of foot sensitivity, small behaviour changes, or just a feeling that the horse isn’t as comfortable as it was a few weeks ago.

What’s usually happening isn’t one single issue, but a change in how the horse is processing the grass.
At this time of year:
grass contains more rapidly fermentable carbohydrates
those are broken down more quickly in the hindgut
and that shifts the pattern of fermentation
That change affects the microbiome and the production of short-chain fatty acids, which are part of the signalling system influencing metabolism and gut function.
At the same time, not all horses are starting from the same place.
A horse that has come through winter lean, and has used up fat stores, will usually adapt to spring grass more easily.

A horse that hasn’t gone through that natural winter phase may find the transition more challenging, because baseline insulin levels are often higher and the system is less adaptable to change.
—
When those two things combine — changing grass and individual sensitivity — you get a horse that is coping…

…but only just.

Why this matters
This is the stage before problems become obvious.
If you wait until there is clear lameness or laminitis, you’re reacting.
At this stage, you can still adjust.

In practical terms, that means:

paying attention to turnout timing
being aware of afternoon/evening grazing
watching small changes, not just big ones

And this is also where microbiome testing can be useful because it shows whether fermentation patterns are staying stable as the grass changes.

Those early shifts in the microbiome often appear before anything obvious on the outside.

Most spring problems don’t come out of nowhere.

They build gradually.

And the horses that stay well are usually the ones where these early changes are recognised and managed early.

Spring grass isn’t just “richer”… it’s fundamentally different.At this time of year, most people focus on how much sugar...
03/05/2026

Spring grass isn’t just “richer”… it’s fundamentally different.

At this time of year, most people focus on how much sugar is in the grass.

But the more important question is:
grass composition is changing right now — and it varies across the day as well

As we move through spring, pasture shifts from storing more sucrose to producing more fructose and glucose, driven by longer daylight and active growth. At the same time, sugar levels fluctuate across the day — typically lower in the morning and rising through the afternoon and evening.

So even on the same field, your horse is not eating the same thing at 8am as it is at 5pm.

And that matters more than most people realise.

Because these sugars don’t just get digested — they get fermented in the hindgut.

Different carbohydrates ferment at different rates, and as these patterns shift, so does the activity of the microbiome. That means changes in short-chain fatty acid production, changes in microbial populations, and changes in the overall chemical environment inside the gut.

And this is where it becomes important.

Those fermentation products play a role in regulating gut movement.

So when fermentation patterns change, the signals that help coordinate gut movement change too.

There is a disruption of the Motility–Microbiome Axis

— where the normal relationship between digestion, microbial activity, and gut movement starts to fall out of sync.

When that happens, you don’t necessarily see an obvious “diet problem”.

Instead, you see:

droppings that aren’t quite right
more gas or bloating
subtle behaviour changes
horses that feel “off” or inconsistent
increased metabolic sensitivity

And it often appears seasonal… because it is.

This is also why turnout timing can make such a difference.

Afternoon and evening grazing exposes the horse to higher levels of rapidly fermentable sugars, increasing fermentation pressure in the hindgut. Morning turnout, by contrast, tends to provide a more stable input and a more controlled fermentation response.

Same field — completely different physiological effect.

The takeaway

Most spring issues aren’t simply about feeding too much.

They’re about:

how the grass is changing
how it’s being fermented
and whether the gut can maintain its normal rhythm as those inputs shift

If your horse struggles at this time of year, it’s rarely random.

It’s usually this.
If you want help understanding your horse’s gut stability this spring, message me.

It’s a very common approach—especially for horses that struggle to hold weight or need more energy.But it’s worth steppi...
26/04/2026

It’s a very common approach—especially for horses that struggle to hold weight or need more energy.
But it’s worth stepping back and looking at how the horse is actually designed to function.
Horses are built to get the majority of their nutrition from forage:
grass, hay, and fibre-based feeds.
Not just for calories—but for how their digestive system works.
Because fibre doesn’t just “fill them up”—it feeds the hind gut microbiome.
And that’s where a significant part of energy production and metabolic regulation takes place.
When fibre is broken down properly, it is fermented by specific microbial populations into short-chain fatty acids.
These provide a steady, controlled source of energy and help maintain a stable hind gut environment.
A key group involved in this process are fibre-digesting bacteria such as Fibrobacteres.
In many managed horses, these populations can sit relatively low—often around 3%.
In horses living in more forage-diverse, lower-input systems, they are frequently much higher.
That difference has a direct impact on how efficiently fibre is utilised.
When these populations are strong:
fibre digestion is more efficient
energy release is more stable
the system tends to be more resilient
When they are low:
fibre is not utilised as effectively
the horse becomes more reliant on readily available sugars or added feeds
and the overall system is often more reactive
Which is why simply adding grain doesn’t always resolve the underlying issue.
Sometimes the more useful question is:
Is the horse able to extract what it needs from forage in the first place?
Forage should always form the foundation of the diet, and in some cases additional feed is necessary.
But supporting the function of the hind gut microbiome can make just as much difference as what is added on top.
As always, any changes should be made gradually and with the individual horse in mind.

Laminitis season again… and the focus is the sameWeightGrassRestrictionAnd yes—those things matter.But I think we’re sti...
22/04/2026

Laminitis season again… and the focus is the same

Weight
Grass
Restriction

And yes—those things matter.

But I think we’re still missing a big part of the picture.

Because I can take two groups of native ponies—both good doers, both theoretically high risk—and get very different outcomes depending on how they live.

My own ponies are on marginal land—mountain pasture, heathland, woodland.
They move, they browse, they forage, and in winter they fend for themselves unless conditions are extreme.

On paper, they should be laminitis-prone.

In reality, they’re far more stable than many horses kept on improved pasture with controlled grazing.

So I started looking at what’s different.

When we test the microbiome, one of the clearest patterns is fibre-digesting bacteria—particularly Fibrobacteres.

In more managed systems, it’s not unusual to see levels around 3%.

In my herd—and in the Carneddau ponies nearby—it’s consistently much higher, often 10–15%.

That’s not a small difference.

These bacteria are central to fibre breakdown and hind gut stability.

So the question becomes:

If the microbiome is shaped by environment…
and the microbiome influences how the horse handles fibre, sugar and inflammation…

are we looking in the wrong place when we focus only on restriction?

There’s a growing move toward regenerative grazing and more biodiverse systems—and I don’t think that’s a coincidence.

Because the more diverse the environment, the more resilient the system tends to be.

Laminitis is complex. It’s never one thing.

But environment → microbiome → metabolism is a link that’s getting harder to ignore.

If you’re dealing with a horse that is “managed carefully” but still not quite right, this is often the layer I start looking at.

Have you seen differences between horses in different environments?

After my last post, a lot of people emailed to say:“This sounds exactly like my horse.”And that’s the problem.From the o...
19/04/2026

After my last post, a lot of people emailed to say:
“This sounds exactly like my horse.”
And that’s the problem.
From the outside, these horses often look:

* well managed
* not overweight
* on the “right” diet

…but something still isn’t right.

Energy isn’t quite there.
Weight doesn’t behave as expected.
Or there’s a constant underlying concern about laminitis or metabolic issues.

The reason is simple:
You’re seeing the *end result*—not the cause.
Insulin resistance isn’t one single condition.

It’s the outcome of different underlying pathways.

In some horses, it’s driven by fermentation imbalance.
In others, it’s gut barrier stress or chronic inflammation.
In others, it’s how the microbiome is interacting with sugars.

And until you identify which one you’re dealing with…

you’re guessing.

This is why two horses on the same management plan can respond completely differently.
And why doing everything “right” doesn’t always give you the result you expect.
This is exactly what we look at with microbiome analysis.

Not just what bacteria are there—

but what they’re doing, and how that’s affecting your horse’s metabolism.

If your horse doesn’t quite add up, there is always a reason.

You just need to look in the right place.

Insulin resistance isn’t just a weight problem.Some of the worst cases I see are in horses that aren’t overweight at all...
16/04/2026

Insulin resistance isn’t just a weight problem.

Some of the worst cases I see are in horses that aren’t overweight at all.

Lean horses.
Carefully managed horses.
Horses that should be fine… but aren’t.

That’s where it gets confusing.

Because obesity—and metabolic dysfunction—isn’t just about body condition.

It’s a complex interaction between genetics, metabolism, environment… and the gut microbiome.

The microbiome doesn’t just sit there passively.
It actively influences how the horse extracts energy from feed, how inflammation is regulated, and how insulin responds.

In many cases, this is where things start to go wrong.

When the hindgut microbiome is disrupted, fermentation changes.
The gut lining becomes compromised.
Inflammatory compounds enter circulation.

The liver takes the hit.
Insulin regulation starts to break down.

And this is how you end up with laminitis…
in horses that don’t fit the textbook picture.

The pathway is real:

Gut → inflammation → liver → insulin → hoof

If you’re only managing weight, you’re often managing the symptom—not the cause.

This is why I focus so heavily on the microbiome.

Because until you understand what’s happening there, you’re only seeing part of the picture.

If you’ve got a horse that doesn’t quite add up… you’re not imagining it.

f you have an easy keeper, the issue often isn’t calories alone — it’s how the hindgut microbiome ferments fibre.Some ho...
09/02/2026

f you have an easy keeper, the issue often isn’t calories alone — it’s how the hindgut microbiome ferments fibre.

Some horses have gut bacteria that are exceptionally efficient at:
• Breaking down fibre
• Extracting calories
• Turning forage into body fat

This is a biological fermentation pattern, not an owner failure.

🔬 What’s happening in the gut?

Easy-keeper horses often show:
• Very high fibre-degrading bacteria
• Low “metabolic regulators” (e.g. Verrucomicrobia)
• Fermentation biased toward energy harvest, not metabolic balance

The result?
➡️ More calories extracted from the same forage
➡️ Easier weight gain
➡️ Higher risk of EMS and insulin dysregulation

🌿 How do you change fermentation without starving the horse?

You don’t cut fibre — you change which microbes are thriving.

One powerful tool is plant polyphenols and bioactive plant compounds.

These compounds:
• Selectively suppress obesity-associated microbes
• Support metabolically protective bacteria
• Reduce excessive energy harvest
• Improve insulin signalling and fat metabolism

🧬 Key anti-obesity plant compounds studied in metabolism

Some well-researched examples include:

• Polyphenols (from diverse plants, herbs, forages)
– Shift gut bacteria away from fat-promoting pathways
– Reduce low-grade inflammation

• Ecdysterone (20-hydroxyecdysone)
– Studied for its role in improving body composition
– Supports lean tissue metabolism
– Helps counter excessive fat accumulation without restricting intake

• Flavonoids & tannins (in controlled amounts)
– Modulate fermentation speed
– Reduce excessive calorie extraction

The goal is metabolic rebalancing, not weight loss by deprivation.

🟦 What this looks like in practice

✔️ Fibre stays the foundation
✔️ No starvation, no extreme restriction
✔️ Targeted plant compounds nudge the microbiome
✔️ Fermentation becomes “cooler” and less obesogenic
✔️ Weight becomes easier to manage

This is working with biology, not fighting it.

🧪 Why testing matters

Two horses can eat the same forage and respond completely differently.

Microbiome testing shows:
• Whether a horse is an efficient energy harvester
• Which fermentation pathways dominate
• Whether polyphenol-based strategies are appropriate

Because you can’t manage what you can’t see.

💬 If your horse gains weight easily despite careful feeding, the answer may not be “less food” — it may be better fermentation.
www.equibiome.org

Over the years at EquiBiome, we’ve worked with a huge range of horses and owners.Some are focused on long-term wellbeing...
22/01/2026

Over the years at EquiBiome, we’ve worked with a huge range of horses and owners.

Some are focused on long-term wellbeing.
Some are managing metabolic sensitivity.
Some are competing at a very high level.
Some just want their horse to feel comfortable, settled, and consistent.

What we’ve learned is that gut health is rarely about one label or one moment.
It changes with diet, workload, stress, medication, seasons, and management — often long before a problem becomes obvious.

That’s why our focus has always been on understanding patterns over time, rather than reacting when something goes wrong.

We use university laboratory processing, Illumina sequencing, and a growing equine microbiome dataset to help make sense of those changes — and to support better decisions around feeding, management, recovery, and prevention.

The science is the same for every horse.
The context is what makes it useful.

Our aim isn’t to tell anyone how their horse should be kept or managed.
It’s to provide clear information that owners can use in a way that fits their horse, their goals, and their circumstances.

That’s the direction we’re continuing to build EquiBiome in — steadily, carefully, and with the long term in mind.

Thank you to everyone who trusts us with their horses, whatever their background or discipline.
www.equibiome.org

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