Laminitis in Horses: Understanding the Condition and its Relationship with Grass

By Siun Griffin, Equine Physiotherapist and LCAO Community Manager 

Spring has sprung and so has the increased risk of laminitis in horses. While laminitis can occur at any time, spring grass in particular commonly triggers this horrible condition.

Laminitis is a debilitating condition that affects the hooves of horses, causing severe pain and lameness. It is a complex and multifactorial disease that can have devastating consequences if not properly managed.

Here we hope to provide a detailed overview of laminitis, what it is, the pathological changes occurring in the hoof, and the relationship between grass consumption and laminitis development.


Laminitis: A Brief Overview

Laminitis, also known as founder, is an inflammatory condition affecting the laminae of the horse’s hoof. The laminae are delicate structures that connect the hoof wall to the underlying structures, such as the coffin bone.

In laminitis, inflammation disrupts the normal blood flow to the laminae, leading to the separation and weakening of the bond between the hoof wall and the coffin bone. This, in turn, causes severe pain, lameness, and potential rotation or sinking of the coffin bone within the hoof capsule.


Pathological Changes in the Hoof During Laminitis

During the development of laminitis, there are several pathological changes that occur within the hoof. Firstly, the inflammatory process triggers the release of various enzymes, which break down the structural proteins holding the laminae together. This enzymatic activity weakens the laminae and disrupts its connection to the coffin bone.

Additionally, inflammation causes increased blood flow to the hoof, resulting in excessive fluid accumulation within the laminae and the hoof capsule. This leads to swelling and compression of sensitive structures, intensifying the pain experienced by the horse.


Grass and Laminitis Triggers

Grass consumption has been identified as a significant trigger for laminitis in horses, especially in those prone to the condition.

The high sugar and carbohydrate content in certain types of grasses, particularly during periods of rapid growth, can lead to an overload of sugars in the horse’s digestive system. This, in turn, can disrupt the delicate microbial balance within the gut, leading to the production of endotoxins that trigger laminitis.


The Grass Cycle and Impact on Laminitis

Understanding the grass cycle and its impact on laminitis is crucial for managing horses at risk. Grass undergoes diurnal changes in sugar content, with the highest levels usually occurring in the early morning and late afternoon. The lowest sugar levels are typically found during the middle of the day and overnight.

For laminitis-prone horses, it is recommended to limit grazing during peak sugar periods, such as early morning and late afternoon. Instead, providing controlled access to pasture during periods of lower sugar content, such as midday and overnight, can help minimize the risk of laminitis development.



Laminitis is a serious condition that can cause significant pain and lameness in horses. Understanding the pathological changes that occur in the hoof during laminitis is crucial for effective management.

Grass consumption, particularly during periods of high sugar content, has been identified as a common trigger for laminitis. By considering the grass cycle and providing controlled access to pasture, horse owners and caretakers can take proactive measures to reduce the risk of laminitis in susceptible horses.

It is important to consult with a veterinarian for a comprehensive evaluation and tailored management plan for individual horses at risk of laminitis. By combining veterinary guidance with appropriate management strategies, the welfare of horses can be safeguarded, reducing the occurrence and impact of this debilitating condition.

For more information on identifying laminitis check out Signs of Laminitis 

Note: It is always recommended to consult a qualified veterinarian for specific advice and guidance regarding laminitis and individual horse care.

For more information on the International Diploma in Equine Osteopathy (Int’l DipEO) program offered at London College of Animal Osteopathy (LCAO), click here