Equine Health: Causes and Symptoms of Laminitis

Laminitis is a crippling disease that affects horses worldwide and has devastating consequences. More than that this is a deeply misunderstood disease that is still completely misdealt with nowadays. For example, did you know that laminitis, often perceived as a hoof disease, is actually a systemic condition with profound effects localized in the hoof? That’s right! So you see, understanding its causes, recognizing its symptoms, and knowing the main management alterations we can implement and the available treatment options is vital for correctly dealing with Laminitis.

Because this is such a complex theme, we decided to divide this theme in two posts. So today we’ll talk about what causes laminitis and next week we will approach how to manage it according to the cause. Are you ready? Let's start.

What is Equine Laminitis?

Laminitis is a painful and complex disease that affects the equine digit. This disease has different causes and ultimately leads to the disorganization and death of the laminas that support the third phalanx (P3), which is one of the bones inside the hoof. This leads to different symptoms depending on the cause and stage of development, including severe pain, lameness and hoof deformation.

What Causes of Laminitis?

Although laminitis manifests as a condition of the hoof, it's crucial to recognize that in most cases this disease is a systemic disorder. This means that a general health problem (in the “entire body”) will manifest itself in the hoof. More than that, the severity of the local damage is directly influenced by whatever is causing it and by how long the horse is sick.

Therefore, understanding the causes of laminitis is crucial for treatment and prevention. “Recently” advancements were made in the mechanisms of laminitis and scientists divided Laminitis in three types, according to the cause: sepsis-related, endocrinopathic and from the support limb.

Sepsis-related Laminitis

This type of laminitis comes as a consequence of another problem in which there is a generalized inflammation that leads to endotoxemia. Endotoxemia is the circulation of toxins coming from within. In these cases, the biggest risk factor appears to be the generalized inflammation itself.

The primary problems that can originate this type of laminitis include gastrointestinal disorders, respiratory infections, anterior uveitis (infection in the eye), reproductive problems (metritis or placenta retention) and an overload of non-structural carbon-hydrates (“sugars”) in feed or pasture.

Endocrinopathic Laminitis

Endocrinopathic laminitis starts slower and is associated with an insulin dysregulation. This insulin imbalance is usually related to the Equine Metabolic Syndrome (EMS) and Cushing disease (PPID), which are hormonal diseases.

However, there seems to be an exception for this type of laminitis, which is the laminitis associated with pasture. This type of laminitis is believed to be an activation of a chronic process of endocrinopathic laminitis but the mechanism of the disease is the same na in the sepsis-related laminitis.

Support Limb Laminitis

This type of laminitis happens when a limb has to support extra weight, while another one is hurt and usually doesn’t have permanent damage.

Symptoms of Laminitis

Early recognition of laminitis symptoms is crucial for prompt and correct intervention. As we said before the clinical signs will also depend on the stage of development of the laminitis and this can be differentiated in three stages: developing, acute or chronic.

Laminitis Caused by Local Trauma

The traumas that can cause this form of the disease include working on hard surfaces or excessive cutting of the hooves. This type of laminitis does not have the classical mechanism, since the inflammation is only local, and usually is resolved very fast without any permanente damage to the hoof.

Sepsis-related Laminitis

This type of laminitis usually presents acute clinical signs that develop quickly after the primary cause (3/4 days). These signs can be more or less serious and also progress more or less quickly. However, these signs are not exclusive to this type of laminitis, because you can see the same signs in an acute crisis of a chronic laminitis.

The most common clinical signs of the acute stage include:

• Altered resting posture, with a characteristic "founder stance" where the horse leans back to alleviate pressure on the affected hooves.

• Lameness in one or more limbs, the animals can even be reluctant to walk.

• Warm hoof Wall, that can come before on when the episode starts.

• Digital pulse in the affected limbs.

• Positive response to the hoof clamp, especially in the toe.

• Incessant alternation of support between the fore and hind limbs, even before lameness is noticed.

However, these signs are not exclusive to this type of laminitis, because you you can see the same signs in an acute crisis of a chronic laminitis.

Endocrinopathic Laminitis

This type of laminitis is the biggest cause of laminitis in the entire world and usually presents a chronic form. A laminitis is considered chronic from the moment there is movement of the third phalange inside the hoof (the bone goes down or rotates). This dislocation causes alterations in the hoof itself and these alterations are often the first sign seen by owner or farrier, without any signs of pain. These hoof alterations include:

• Alteration of the growth pattern of the hoof:

  • Presence of growth rings or ridges in the hoof wall.

  • Depression of the hoof wall.

  • When not trimmed frequently the hooves resemble “Aladin shoes”, because the heels grow faster than the toe.

  • Enlargement of the white line.

  • Haemorrhagic spots.

• Depression in the coronet, that in serious cases can even separate.

• Bulge on the sole and, in extreme cases, a semicircular separation of the sole in the toe, which means that the bone is starting to penetrate the sole.

• Pain might not be present and when it is, it’s usually associated with abrasion of the sole or hoof abcess.

AGAIN, chronic cases can have acute crisis, in which usually the sepsis-related mechanisms are activated.

In this hoof we can see that although very light, the toe is already going forward and some growth rings.

Equine laminitis is a horrible and unfortunately very common disease, and like most diseases Knowledge is everything.  As you’ve seen by this post it is only by correctly identifying the cause that we can implement the right measures to deal with and prevent laminitis. Next week we will discuss what exactly we can do to deal with each kind of laminitis.

Also, we know that this is a complex theme and sometimes it is hard for us to explain something in a simple way. So, if you have any questions DO NOT hesitate to contact us. We will answer your questions and you will help us improve the way that we are exposing our content.

See you next week,

Isabel & Stephan