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Look up Mallenders/Sallenders online and you'll be told that it's "a heartbreaking and tenacious skin issue ... presenting as an accumulation of thickened, crusted scale and scabs on the front and hind legs of horses."

FACT - Mallenders/Sallenders is now recognised as one of many chronic health syndromes connected to the now widespread multi-metabolic detoxification disorder called Cryptopyrroluria, aka KPU.

A common ailment in Gypsy, Shire, Friesian - pretty much any hairy, heavy, draft-type horse ... mallenders/sallenders is said to be caused by "excessive keratin production," aka hyperkeratosis. Then again, depending on what you read, apparently it isn't - the jury seems to be out on this one. Either way, going by what our clients say, I can definitely concur on the 'heartbreaking and tenacious'.

Treating it is said to be an absolute nightmare. Soothing ointments of various descriptions are applied to soften the scabs, which then seem to return with a vengeance and spread onwards and outwards, leading to secondary fungal and bacterial infections that may lead to lameness.

Clipping the hair back to get to the scabs is an even worse nightmare - the horse is in constant self-preservation react mode, because mallenders/sallenders hurts. Worse still, harsh liver-damaging chemical treatments via the Deosect jab or Frontline are applied to kill off the apparent resident mites in the feathers, yet don't seem to work either.

So what to do? The general school of thought is to avoid biotin, and keep applying the ointments. But surely, there has to be something at the root of it all? Surely if we knew what caused that, we'd know what to do to prevent this truly awful syndrome?

Cut to 2021 ...

... and there's new science out there. The science is showing that mallenders/sallenders is connected to the now widespread - and spreading - multi-metabolic chronic detoxification disorder called Cryptopyrroluria, aka KPU. (See our separate KPU page for the full story. Warning - it's proper Science Alert 🤓).

KPU is basically all about liver/kidney issues, and specifically a dysfunction in the detoxification process, but as always, it all begins in the gut, specifically the hindgut, triggered by dysbiosis in the hindgut microbiome. And when there’s hindgut dysbiosis, there’s an overload of toxins for the liver to metabolise (correct name biotransform).

Thing is, the kidneys are very much involved as well because the liver shunts all the transformed toxins to the kidneys for excretion, but if there’s a toxicity overload the kidneys become overwhelmed as well, so can’t shift all the toxins out through the urine. So, they use the emergency excretion pathway – the skin. Cue an excess of toxin residue on the skin surface, very often bringing with it incessant and agonising itching as well.

Of course, as science would have it, it’s a whole lot more complex than this! But at the very root of the problem lies a tiny, yet critical, micronutrient - vitamin B6. And here’s why.

Vitamin B6 - Introducing P5P

The hindgut produces B6 in its activated form – scientific name P5P (Pyridoxal-5-Phosphate), and absolutely not the synthetic form we see in off-the-shelf B-vit supplements (Pyridoxine), which the equine gut neither recognises nor knows what to do with, so shunts it straight out for excretion. As the saying goes, 'An expensive way to make urine' 😉. Seriously, save your money - and the extra work on your horse's liver.

I digress. However, when the hindgut microbiome is disrupted (dysbiosis, aka more of the bad pro-inflammatory gut-damaging microbes than the friendly, beneficial microbes), the activated B6 ‘P5P’ production becomes deficient, and here’s where it all goes badly wrong because … the liver needs this activated form of B6 - P5P – to biotransform, as in break down/metabolise – those toxins. NB - the human gut can convert pyridoxine to pyridoxal-5-phosphate, but the equine gut can't.

It’s one big knock-on effect

If the skin has a problem it’s because the kidneys have a problem, because the liver has a problem, because there’s not enough P5P being produced, because … and here’s where it all starts – there’s a gut microbiome imbalance. Which means the liver and kidneys can’t do their job so the whole natural detoxification process gets messed up. And this is why horses get skin problems.

Worse, not only is there the toxicity overload, but these toxins are also damaged, dangerous, putrefactive (relating to or causing decay) toxins because the liver hasn’t been able to break them down properly, and this is why the presenting symptoms are such a nightmare.

Which brings us neatly to mallenders/sallenders, because ... It’s the same scenario, but unlike a one-off hindgut disruption that can fairly easily be cleaned-up, the M&S horse is in a state of permanent, chronic, skin disruption.

Cut to March 2021

And - just this year (March 2021), the latest research is showing that this same gut:P5P:liver:kidneys scenario is now thought to be what’s behind mallenders/sallenders (amongst many other syndromes) – namely an overload on the kidneys due to the liver/P5P dysfunction as a direct result of hindgut dysbiosis. But – when it’s an ongoing, chronic, permanent condition, it’s actually a much bigger picture than this, as any M&S horse owner knows. Enter the now widespread multi-metabolic chronic detoxification disorder - Cryptopyrroluria, aka KPU.

And - M&S isn't a syndrome that a horse has simply picked up along the way; it's thought to have started from birth, and how the horse as a foal was raised. (All explained in our KPU page).

So, pulling this altogether, what to do?

Simple. We need to clean up the gut:liver:kidneys pathway and restore the P5P production.

First up, and the key is to restore the natural microbiome in the colon; only a horse with a healthy hindgut biome can produce enough P5P to have a normal, healthy, liver biotransformation function. And the only way to fix the hindgut biome? A hindgut restoration programme, and ... feed our horse right 😉

So, it’s all about hay, 24/7, 365-days/year, for the cellulose fibre content to restore the beneficial microbe population. If you feed a horse haylage, forget it. If you soak your hay for a long time, forget it. If you let your horse run out of hay, especially if stabled overnight, forget it.

So, feed hay, hay, and more hay, and for the feedbowl feed a basic grass-fibre cob as the base carrier for the mineral balancing nutrients, salt for the crucial sodium, and micronized linseed for the omega-3 EFA. (Or see our VitaCompleteM&S which includes both salt and linseed).

If haylage was fed, the gut also needs to deacidify, so feed Spirulina for a couple of weeks which is an excellent toxin-binder and is mainly excreted via the liver-bile-intestine route, thus relieving the kidneys.

Meanwhile, what not to feed! No beet, no alfalfa, no sugars, no pectins, no muslis, no pellets, no treats, and definitely no feedbags with pro-inflammatory gut-damaging wheatfeed, oatfeed, soya, NIS, basically anything listed in our The Feedbowl – what’s really in those feedbags page. The more basic the feeding program – in other words, the more species-appropriate, as in what a horse is meant to eat and what a horse’s gut is meant to digest – the faster the hindgut environment will be restored to normal.

This is all covered in our Feeding our Horses section off the main menu, and specifically the Why what we feed has to be right page. Or, if you’re stuck, feel free to email me your current feed regime in case there are triggers we can identify here – everything that goes in your feedbowl, so all brands/supplements etc., and forage, so turnout, how long etc., and dried, so hay/haylage and how much.

Now we need to clean up the hindgut microbiome, liver and kidney function and restore the P5P production.

  • First up, we need to follow a hindgut-regeneration programme with a 1-month (1kg) course of our SIBO-CARE blend.
  • Alongside this we reconnect the gut membrane with a 1-month course of our GutAminos, a combo of two vital amino-acids for the cellular membrane protein repair.
  • We also need to feed Pyridoxal-5-Phosphate - P5P - we sell it in powdered form.
  • When the hindgut regeneration programme is finished, take a 1-week break before we start on toning the liver/kidney function - feed our LKLCARE for 1-month (1kg).
  • We also recommend feeding our WildFed mix as it’s vital to support the horse's natural eating behaviour.

Meanwhile, come back to us for advice on long-term support if needed, as M&S/KPU horses may benefit from constant metabolic support until the body is back in balance.

Meanwhile, from a mineral standpoint we have a dedicated EquiVita/VitaComplete 'M&S' range for the mallenders/sallenders horse excluding biotin - with some pretty powerful testimonials on the page, plus we have our own hand-crafted scab-softening aloe gel - M&SGel, made from certified organic ingredients.