Posted in  Understand Hoof Health  on  7 March, 2019 by  Debs Crosoer

White line separation is a common problem, often causing great worry to horse owners, and leaving them obsessively scrubbing at the white lines digging out stones, and in what little time they have left, tearing their hair out.

It doesn’t have to be that way though. It can’t always be completely fixed, but it can most of the time. A good understanding of what’s going on can go a long way to reducing the stress even in those stubborn cases.


What is the White Line?

The white line is, frustratingly, not the visible white line you can see – that’s the inner wall (I’m sorry, I didn’t name these things). The white line is the yellow line you can see between the inner wall and the sole.

It’s essentially like a sealant. It fills in the gap between the sole and the wall. It’s much softer and more flexible than the horn of the sole and inner wall, so it’s often a little recessed.

It’s most definitely not a weight bearing structure. I know there is a trim method out there that says it should be, so if you come across anything suggesting that, don’t back slowly away – turn and run (screaming or not, is entirely up to you <img draggable=)

The white line grows from the edge of the sole corium and fills in the gap left by the sensitive laminar.

(stand back it’s time for my crazy colouring diagrams again!! You know you love them!)





With a freshly trimmed wall, you can see how the insensitive laminar and the white line connect.


stretched white line

What Happens When the White Line Stretches?

The white line is part of the hoof capsule. When it stretches just a little, as it has some flexibility, it can just get a little wider than it should be. If it stretches a little more, the insensitive laminar detach leaving little holes.



It’s these little holes that get little stones in them. This is the part that people find most frustrating. The stones end up making bigger holes, it’s a self-perpetuating problem.


Is It Serious?

Remember the white line is the part of the hoof capsule that fills in below the sensitive laminar. If the white line is stretching, then so is the laminar. This is a much more significant problem than a stone stuck in the white line.

Don’t panic just yet. As terrifying as this is going to sound, you really don’t need to panic about a stretched white line. I’m hoping this post is going to help you understand what’s going on, so you can focus on the most effective solution. It’s not supposed to freak you out. That never helps anyone.

Stretched white line is, however, the beginning of the laminar failing. It’s a step towards the pedal bone detaching and rotating (there’s quite a few steps, you don’t need to panic yet, but it is a step in that direction). There’s simply no way to sugar coat that, sorry.

Stretched white line is a mild version of laminar wedge. Laminar wedge is what happens when the sensitive laminar fail and the pedal bone starts to rotate.


What to Do About It

First things first. Find out what’s causing the problem. It’s not simply leverage, or shoes, or the foot being over grown.

You’re looking for causes of mild inflammation/laminitis. It’s most likely a dietary problem of some sort. Nutritional imbalance, gut problem, endocrine problem (EMS, PPID), allergy or intolerance, arthritis. If it’s a recent occurrence, mud fever, wormer, steroid, virus…

The list of possible causes is vast, and don’t forget you’re often looking for a small problem. Something that’s a bit off, rather than something big and obvious.

Not all causes are so easily addressed. You may find that a weakened white line is just part of your horse’s condition. Understanding why it’s happening can make it less stressful (I hope) and it can become part of how you monitor them.

Next, you’re going to want to do something about those pesky stones.

This is a bit of a balancing act. Too much picking and scrubbing will cause further damage to the white line, which is the exact opposite of what we’re aiming for. Not doing anything can result in stones being pushed further in and causing more damage to the white line.

That’s as frustrating for me to write as it is for you to read. Sorry (I feel like I’m apologising a lot in this post! I’m sorry <img draggable=)

In mild cases, sometimes you don’t need to do anything. There are times, that simply addressing the underlying cause is enough.

How bad the problem of stones getting stuck depends on all sorts of things, from the weight of your horse, to the gait, the surfaces you’re going over, how much ridden work is done, how strong the rest of the feet are…


Pick the stones out carefully. A hoof pick is often ok, but sometimes you might need something a bit pointier. A small screwdriver is pretty good for this, if you’re careful and not poking it everywhere, making the problem worse. A shoeing nail is awesome as well, though small enough to get lost easily.

A wire brush can be great, but again, don’t be over-zealous. The white line isn’t as tough as the rest of the hoof horn. While you can scrub at the sole and wall endlessly without causing a problem, for the white line, less is more. I don’t often advise moderation, so when I do, please heed my call.

Once you have the stones out, it’ll take approximately 2.3 seconds for more stones to get in. You might find a hoof putty useful to fill in the white line. You will need it to dry first before letting the hoof loose on stoney surfaces. This will need regularly reapplying. It tends to only work on the bigger holes, so when you only have tiny holes, there’s not much that can be be done to fill them in.

I use Red Horse Artimud if you’re wondering (and nope – that’s not a sponsored link, I’m just being helpful)

If you’re addressing the right problem, then stretched white line needn’t be so frustrating to deal with. A combination of finding the underlying problem, while managing the external symptom can get things under control.

There are a few conditions which give you low levels of inflammation that aren’t always under your control (EMS, PPID, Arthritis). While knowing that white line separation is one of the symptoms doesn’t necessarily help you solve the problem, I have found an understanding of what’s going on makes it less stressful. I hope that’s the case here.

White Line Separation is something you want to take seriously, but it’s not something you need to go into full panic mode about. Speak to your hoof care practitioner about it, and really dig down into what might be causing it.

If you want to learn more about other signs of inflammation that may be affecting your horse, you may be interested in the course below.

Laminitis Warning Signs

Laminitis can affect any horse...

Does your horse suffer with Foot Soreness, Persistent Hoof Infection, Wall Cracks, Flare, or Underrun heels?

These problems can be signs of low grade laminitis. Inflammation (laminitis) in the hoof can cause deformity and soundness issues. Trying to fix the hoof without identifying and addressing the inflammation feels like pushing mud uphill.

Do you know what to look for? We discuss 35 different early warning signs that inflammation is affecting the hoof, explaining anatomy and function, what laminitis is, how it affects the horse and hooves and practical things you can do to address the problem without losing your mind!

About the author

Debs is a practicing Equine Podiatrist with over 15 years experience, author, and educator.

She’s here to show you how to simplify your horse’s management painlessly so you feel in control and have a straightforward system that works for you.

When she’s not working you can find her playing with her own horses, watching geeky sci-fi or baking epic cakes.

  • I totaly agree that to find the underlaying cause is the best way to treat this. And in most of the cases this has to do with the diet – and the amount of sugars to be more precise. I would say that picking the hoof is helpless if you don´t do anything to decrease sugars in the diet.

  • is an abcess likely to cause this too, i have a small area of stretched white line, exactly where we abcessed and where it is growing down the hoof wall. Hoping it will right itself shortly as almost grown out. i also use red horse artimud, it has been excellent at keeping out those pesky stones!

    • Yes, absolutely. An abscess can cause detachment between the wall and sole, if that’s where the puss came out. Abscess also cause a lot of pressure in the foot which can result in the white line stretching.

      • My mare has been lame 3 months, intermittently fracture lame. After a visit from the vet who diagnosed arthritis (as she was sound in trot on a straight line when he came). She has separation of the white line which I’m stuffing with cotton wool and field paste in between poulticing.. yesterday I saw the abscess near the surface of the coronet band.. she was very reactive to my touching it, today, nothing!

        I am concerned about the white line separation but vet said it wasn’t lami.. and she does have concavity in the foot. She was double wormed for tape just before the separation occurred so Im wondering if this has been a contributing factor, along with poor trimming, which has resulted in sore withers, which of course will result in incorrect loading.. chicken and egg scenario I find myself in at the moment!

  • Hmmmm my pony reacted to her flu/yet vaccination with a fever for a couple of days and got Danilon. I think that could be why she suddenly went footy and has stretched white lines!! Annoying as she was totally sound and going well before. I do love being able to find a cause for an effect though!

    • It is helpful when you know what caused the problem. Sometimes the most difficult part is figuring out what caused it, and how to remove it.

      Sorry your pony has been having trouble, but YAY! for knowing what caused it! 🙂

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