This article is going to cover the topic of cracks in the hoof walls of horses. When evaluating the health of a horse, it’s common to start at the hooves and work our way around. The hooves can tell a LOT about a horse and having cracks in them is a sign of a few things. It’s important to note that hooves should not ever have any cracks in them. They should be smooth, without cracks, rings, grooves, chips or any other visual deformities. While this may seem an obvious point, it’s amazing how many horses go so long with these things without treatment or care. I definitely recommend reading over our hoof anatomy article briefly if you aren’t sure of some parts of the hoof.
When checking out hooves, the first visual we get as we are walking up is the outside of the hoof. Looking at heels, toe, coronet angle, flare both in the quarters and toe and cracks. A lot can be told about the hoof just from a quick glance, from there it’s about verifying those worries by checking in closer and from the sole.
Here is a pictures of a hoof that has some pretty severe problems, just glancing from the side and front:
Now without scrolling down to the next image, can you see what is wrong with this foot? Let’s take a look at a notated picture of this and talk about it:
The first thing we can see that sticks out is the big crack right down the middle of the hoof. There are other cracks throughout this hoof, but this is the most concerning as it goes right up to the coronet. As we take a look at the lateral view of this hoof, we will see exactly why this is happening. From there we can also see that the quarters are both heavily flared, especially the lateral side, which is common. We can see that this horse is likely landing toe first a lot and the whole shoe and hoof is being pushed up/ground off as the thickness of the shoe at the front compared to the thickness of the back is huge. We can also see that the shoe is not sitting on the sole of this foot as it must sit on the flare. This will lead to sinking of the skeletal structure, and unfortunately, thin soles. Essentially this horse is foundering and chronically laminitic. If left in this state, this foot will absolutely get to pedal osteitis as the horse tries very hard to not have it’s coffin bone reach the ground. While this isn’t decisive from the cracks, as this article is about, it’s something we can use to confirm the other symptoms we see.
The red lines on the side show where this hoof should be in terms of being well connected to the internals of the foot. The orange line is what is perceived in this picture of the coronet. It’s hard to tell without pulling the hair up above the hairline but it’s close. The circle in the middle is indicating the large crack. There are others if you look close.
Let’s take a look at the lateral view:
Again, without scrolling down, can you see what is going on here? It’s very serious. Here is the same picture with notations:
Here we can see how much toe this horse has that it shouldn’t have. The red line on the right indicates where the outside of the wall should be. This is exactly why there is a crack down the middle. We can see the tubules of the hoof being pulled forward a lot and based on this we can make a very good guess that the frog too is being pulled forward. The heels are well on their way to being run under as the whole hoof wall from the quarters back is pulled forward. It’s just a matter of time without a proper trim and care.
The two circles are where the nails have gone through. If this horse was not laminitic and didn’t have the huge protective laminar wedge then the nail would have easily gone through the dermis and epidermis lamina and there would be blood. They are way too high and in the hoof to not have. Luckily, in fact though very unluckily, this horse is very likely in a chronic laminitic stage of it’s life and doesn’t have any live epidermal lamina on that part of the hoof. It’s dead and has no connection to the internal parts of the hoof. This horse is likely in serious pain every day of it’s life but has probably learned to tune it out to survive.
We can see the cracks on this side too as this hoof struggles to stay together through the forces of impact and strain of being forced out in a destructive flare.
Let’s take a look at the left side:
This hoof is in far worse shape. While the right side had one very obvious crack, this one has multiple.
Again the left and right lines are where the outside of the hoof wall should be coming down. Severe flares. All major cracks are circled. Also, to note, if this hoof was x-rayed, I would guarantee there is some rotation happening and the p2 bone has sunk into the hoof. More precisely put though, the hoof wall has migrated up the foot as the sole has thinned out and the bone is precariously close to ground level. This image also shows how obvious the shoes are putting all of the stress on the outer wall and laminar wedge, none of it is on the sole and the horse is hanging on it’s laminae. Which obviously is barely attached.
Here is the lateral side of the left foot:
Here we see the stress this hoof is under with a modified coronet band and more cracks. This hoof has an even further underrun heel and severe toe flare. The toe landings indicate the back of the foot is in pain and I would imagine thrush as well as the frogs are definitely not reaching the ground unless they are heavily overgrown.
The point of this pictures, drawing on them and pointing out the problems is that cracks are almost always there due to forces on the hoof wall that it can’t handle. Imagine taking a plastic cup and putting it upside down on a table. Then push down on it from the top and see what cracks first. This is the exact same thing and the major issue of cracks is that it compromises the hoof wall’s strength and integrity to help support the horse’s weight with the sole and frog. It also allows fungus to start to grow and can very much help destroy more hoof wall from the inside. If it was able to get in far enough then you will now have issues with rehabilitating the lamina as the horse fights to keep the fungus and bacteria out.
Cracks in the hooves can also indicate a poor diet. I’ve not bothered covering that here as these hooves don’t particularly show that other than perhaps too much sugar, which may have caused the original laminitic event. From there though it’s anybody’s guess without more information from the owner. These hooves are very likely cracked due to destructive forces on the wall that it can’t handle anymore and as such, it cracks outwards. Tubules can expand a bit outwards but not much and it’s like the grains of wood. They travel up and down, not sideways, which makes them easy to split if force is applied to the top and bottom of the grain. Sideways compression just leads to them getting squished together tighter. Vertical compression and concussion and flare, lead to cracks. Like wood. To treat this, the hooves need to be trimmed to get the walls to grow down well connected and meet the forces of ground impact properly rather than the tubule crushing way they are now.