Content

1. Intro
2. It all starts with the dam's hindgut
3. Where it all goes wrong
4. The research
5. Prolonged diarrhea
6. Summary

There’s an often completely ignored, yet very important consideration when it comes to raising a foal in their first few months, and that’s about creating their microbiome. How a foal’s microbiome is established will basically determine their health – or unhealth – for the rest of their life.

That first year of the foal is crucial, and very much depends on how the mother was fed, because a foal eats its mother’s faeces to build its own microbiome – a process known as coprophagia.

Recent science (2021) now knows that if the dam has a disturbed microbiome, the foal will end up with the same poor-quality microbiome. As a result new breeding practices are now putting mares with poor hindgut function in with other mares known to have a healthy microbiome, so the foal will eat mixed faeces to give its own hindgut a better chance for good microbe colonisation.

Otherwise, if the foal is unable to establish a healthy microbiome, you have a metabolic-risk patient for life, because if a healthy microbiome isn’t there to start with, it’s very difficult to restore and recreate.

It all starts with the dam's hindgut

In a grown horse, the hindgut – the large intestine, and specifically the cecum, is a huge fermentation vat full of micro-organisms - bacteria/fungi/protozoa et al - which digest (ferment) plant fibres; in the horse's case it's cellulose/hemicellulose.

Once the eaten grasses, barks, leaves, berries and woody forage/roughage have been ground down by the teeth, then made its way through the stomach, the small intestine, and finally to the large intestine, these microbial organisms now mix with the digesta and start degrading/fermenting the plant fibres into their nutrient components.

First up, the horse’s main energy source is produced via three volatile fatty acids – butyrate, proprionate and acetate, plus several amino acids, and vitamins K plus two vital B-vitamins - B12 and B6 in a specific ‘activated’ form. It's this activated B6 which is critical for healthy liver and kidney function (see our KPU page for the full explanation).

However, those microbes need to get in there first! When a foal is born their gut is still sterile, so microbes need to get to the hindgut – hence coprophagia. As the foal develops they start to eat mum’s faeces and forage, in around a 50/50 split of each - 50% plant fibres and 50% mum’s microbes from her faeces, and so the foal builds the same microbiome as mum.

This is how the gut microbiome is formed in any horse. A foal’s foregut (stomach) won't be too acidic yet, so the microbes can safely get to the hindgut without being disinfected and/or killed off by the stomach acid. Then along the journey through the small intestine they’re then recognised by the new immune cells that acknowledge these are the foal’s individually personalised microbiome microbes. And that’s basically it!

They then stay for the foal’s entire life with the immune cells thereafter recognising - and swiftly dealing with - a microbial ‘invader’. This is exactly the same for us humans where we’re nurtured from birth via the mother’s breast milk; our own microbiome is then created identically from our own mother. Hence why breast is best and not bottled, with human studies these days showing that a huge percentage of people with various autoimmune syndromes/allergies are due to a poorly created microbiome from birth, aka bottle-fed.

Back to our foal and this process takes around 4-5 months of regularly eating mum’s poo to create a stable microbiome in their gut system, and what eventually builds their ability to finally wean off their mother’s milk to grass forage and roughage.

In nature this is a really smart system, because only a mare with a healthy biome is able to get enough energy from her feed to produce a foal – a mare with a poor biome won't create enough energy to produce a healthy foal. It's been said that a disturbed biome will die off with those mares, so evolution continues to create only strong foals which create a strong herd, which has a direct healthy relationship with the soil and landscape. Nature gets it right, but as always it can all go wrong when us humans get involved, so here's a handy link to the next para.

Where it all goes wrong

This coprophagia process during the first 4-5 months is crucial for the foal – disturb it, and we’re looking at lifelong digestive and metabolic problems. If a foal is given antibiotics, this disturbs the process of the microbes learning to live in the gut, exactly the same with us humans. It’s said that a gut microbiome never recovers after just one course of antibiotics. This also explains why foals that are weaned too early end up with multi-metabolic disorders in later life.

We get the same problems if we feed both mother and foal inappropriately. Haylage is a huge culprit here because haylage contains lactic-acid bacteria, which is one almighty pro-inflammatory, gut-damaging, pathogen microbe that we never want in the gut system. Why? Because it produces lactic-acid gas in the hindgut, which not only blows up and expands the intestines and tears the fragile membrane wall (leading to leaky gut), but it also sours the hindgut pH value, when the intestinal environment should always remain at a neutral pH. Rest assured those lactic-acid bacteria will keep on multiplying, because being acidic themselves they survive their way through the stomach acid. So, if you feed haylage, cue the cascade of hindgut acidosis/dysbiosis/SIBO/leaky gut/faecal water. It won't happen overnight but it's a stealth syndrome, with syndromes usually starting to show anywhere from 2-3 years on. All covered in our Gut System chapter.

Now here's a thing. If we feed haylage to a foal, the immune system then mistakenly accepts lactic-acid bacteria as 'normal', so it’s acknowledged as a resident for life. This will forever and thereafter affect the cellulose fibre digestion, due to permanent dysbiosis in the hindgut, eternally disrupted with an overpopulation of those pathogen lactic-acid bacteria over the friendly fibre-fermenting microbes. It’s fine for ruminants, i.e. cows, sheep, goats, who have a completely different four-chambered stomach and ferment fibre in their rumen, but absolutely not for the equine gut system which ferments fibre only in the large intestine.

We need to change our feeding practice to create a more hostile environment for the pathogen microbes, allowing the beneficial microbes to recolonise and outgrow the bad to restore the microbiome. We do this by feeding quality, adlib, meadow hay, because the hindgut-appropriate fibre resides in those grass stems - there's zero fibre in short green grass blades so a horse needs access to adlib meadow hay, or uncut still-growing long-stemmed grass at all times. However, feed haylage and you’ll create the wrong microbes which will always outgrow the good guys.

Sadly, this is now so widespread that we’re already seeing foals with metabolic problems, i.e. sweet itch being seen at age of 2, never mind so many young horses already allergic to just about everything, and all due to a damaged microbiome. And all due to a completely man-made decision.

The research

So, get the forage (and feedbowl) wrong and it creates unwelcome microbes in the gut microbiome which are passed on through the generations. For the last 20-30 years, most research has been focused on feeding the small intestine, because for scientists this is where the most interesting, complex digestion takes place – sugars, fats, proteins and carbs. Yet it's the hindgut where all the important action takes place, producing those vital metabolites that create those vital nutrients and the horses energy. Research is only now, over the last 5-years or so, coming to realise that studies on the equine hindgut have been badly neglected. Healthy hindgut = healthy metabolism.

With all the human microbiome research intensifying over the last decade, i.e. on IBS, Crones, Celiac etc., it’s now known that the microbiome manipulates everything, literally every function in the body. Hence interest has thankfully now grown for the equine gut with early developments in research out there and with early publications coming out.

The realisation is that it's a given that horses with significant metabolic disturbances have a disrupted microbiome, i.e. of course the EMS/IR/lami-prone horse, but also chronic colicing, diarrhea/faecal water, bloating/gas, multiple allergies triggering an autoimmune overreaction in the immune cells - even headshaking's been mentioned. All signs of dysbiosis in the hindgut. This can all be prevented by giving a foal the chance to colonise its cecum microbes from their hindgut-healthy mother's faeces, or from a different hindgut-healthy mare.

Prolonged diarrhea

🤓 Science-Alert!  We all know that prolonged diarrhea in a foal can be seriously dangerous. This is all cellular-related, and where the salt:water connection is so important. This may sound a little science-y but bear with me,

The body’s cells need a distinct pressure to function, reason being that unlike plant cells which have a solid wall, mammalian cells don’t. Our cells have a permeable membrane wall around them, and in order to work, cells need the right water pressure inside each and every one of them, in their intra-cellular environment.

This is called osmotic pressure, and it’s regulated by salts and water. Thing is, water in the body doesn’t have a pump to move it around, so this is where salt comes in. Salt attracts - draws - water, so where salt goes, water follows, and this is all controlled by the kidneys doing clever stuff by naturally holding back, or excreting, salt and/or water where needed. With me so far?

So, if a cell’s intelligence knows that it’s drying out and shrinking, it absorbs - takes up - salts from the extra-cellular environment (the fluid area outside the cell) and water will follow. Equally, it can excrete salt for the water pressure to follow if it’s too full of water. The cell’s natural intelligence regulates its own osmotic balance, but there has to be enough salt and water available in the whole body, which is all regulated by those clever kidneys.

This balance breaks down if there’s prolonged diarrhea – same with dogs if they vomit for days on end, a typical sign of kidney issues. As the body dehydrates, urgent attention is needed with the salt:water regulation, which will now be significantly out of balance and will cause the body to dehydrate further.

Hence why diarrhea in young foals is so serious because their body is so small, so they dehydrate very quickly. Hence why it's so vital to monitor hydration, and carefully manage supplementing salt/electrolytes to the feed.

Summary

In that strange, perfect, parallel world where none of us live in, wouldn't life would be so much easier if we could simply feed healthy, biome-appropriate, cellulose fibre-digesting microbes to our horse when there’s a biome disturbance, to regenerate the beneficial biome and outgrow the bad guys. This way we’d simply be able to restore the natural biome that the equine gut system is evolved for. Sadly, though, such a thing doesn’t exist.

We now know the health risks of lactic-acid bacteria residing in the large intestine, and a 2020 publication courtesy of Dr Christina Fritz is now showing that feeding yeasts may also negatively disturb the equine hindgut biome.

Long and short, for those of us with horses experiencing never-ending multi-metabolic disorders (see our KPU page), if there’s any possible way to check the history of our horse back to birth, we’d have more of a clue as to how they were initially fed/raised/weaned. Hopefully we'd find that no antibiotics or haylage were fed in the first 6-months of their life, or that the mother unknowingly already had hindgut dysbiosis.

PS – food for thought. This is also very much connected to why there are so many issues with importing horses from one continent to another. For example, bring a horse from Iceland to Spain and their digestion will fall apart because they’re now on completely different forage/roughage to what they were raised on. Or bring a horse from Spain to the UK and watch major metabolic disturbances occur as they chow down on our neon-green grass-blades with no-fibre, instead of their dry, stemmy grasslands and hay diets that their guts were previously used to. All because their microbiome is originally matched to their native forage on which their microbiome was made.

There is a shred of good news here though - with each generation their gut systems will gradually better adapt.

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