Got Questions about Laminitis?

Do you have questions about laminitis and the effects it can have on livestock? Here are answers to the 6 more commonly asked questions about laminitis.

1. What is laminitis?

Laminitis can be a debilitating, and even fatal, disease of the hoof. In the horse, the hoof wall is connected to the coffin bone through a complex arrangement of finger-like projections called laminae.  These tissues provide shock absorption and anchor the hoof capsule to the coffin bone. When the laminae become inflamed, or blood flow to this tissue is disrupted, laminae health deteriorates and the structural support provided by the laminae weakens, allowing the coffin bone to rotate downward or sink. Rotation of the coffin bone is referred to as founder. In severe cases, the coffin bone can actually penetrate the sole of the foot. While laminitis can affect all four feet, it is most commonly seen in the front feet, as the horse bears more than 60 percent of its body weight on the front feet.   

2. What causes laminitis?

A variety of factors are believed to contribute to development of laminitis, including physical or mechanical changes to the hoof (such as trauma, excessive concussion or weight bearing), exposure to black walnut shavings, or a retained placenta following foaling. Endocrine disturbances associated with obesity and the development of insulin resistance in horses have also been implicated as potential causes of laminitis. However, in many cases, laminitis is the result of over-feeding. While most horses can tolerate moderate levels of carbohydrates in their diet, excessive ingestion of non-structural carbohydrates (NSC), including starch, sugars, or fructans can cause metabolic disturbances that result in laminitis.  

3. What role does NSC content play in laminitis?

The term non-structural carbohydrate (NSC) is used to describe the non-fibrous carbohydrates found in plant material. NSC includes simple sugars, starch, and fructans (a complex sugar) and generally calculated as starch + water-soluble carbohydrates (WSC = simple sugars + fructans). Alternatively, the term structural carbohydrate is used to describe the fibrous carbohydrates that are more slowly fermented in the hindgut of the horse. 

4. What is the NSC content of common equine feedstuffs?

Cereal grains such as corn, barley, and oats contain significantly more NSC compared to forage. While NSC levels in properly stored hay tend to remain relatively unchanged, NSC content of pasture can fluctuate relative to time of day, season, or pasture species present. Research has shown that NSC levels tend to be highest in the spring and fall months – times associated with increased forage growth rates. NSC levels also tend to rise over the course of the day, with highest levels in the afternoon and declining over night. Cool-season grasses are typically higher in NSC than warm-season grasses or legumes. 

5. How do we prevent laminitis?

As managers, it is important to monitor our horse’s intake. Follow feeding directions on manufactured feeds and do not feed excessive amounts of cereal grains. If large amounts of grain or feed need to be fed for the horse to maintain proper condition, then it is recommended to switch the horse to a more nutrient-dense feed. This allows for feeding a smaller, safer amount of grain or feed (reducing the potential for laminitis) without sacrificing the nutritional needs of the horse. 
Gradually introduce horses to spring pastures if they have not been eating fresh forage through the course of the winter. Beyond adapting horses to lush pastures, consider limiting access to these pastures to a few hours per day until the forage is more mature, as immature, rapidly growing forages are high in NSC. 

6. How do we manage and feed laminitic horses?

Horses that have experienced one bout of laminitis are often predisposed to future episodes; therefore, it becomes important to manage these horses in a way that reduces the potential for future problems. Proper nutritional management focuses on limiting the amount of NSC the horse consumes, as well as preventing excess body weight that may exacerbate the problem.
There are a couple of feeding options available. Regardless of the feeding approach used, it is important to limit forage NSC intake. The easiest way to do this is by housing the laminitic horse in a drylot, completely restricting access to pasture. Many horse owners prefer not to do this, because it means separating the laminitic horse from his herd-mates. However, this is generally the best scenario for the horse, as it is really the only way the owner can completely control intake. 
Hays with lower NSC levels should be fed to laminitic horses. Regardless of type (legume or grass), hays harvested at later maturity have a lower NSC content than those harvested at early maturity; they also tend to be less energy dense. For many laminitic or laminitis-prone horses, maintaining healthy body weight is key in the prevention of future episodes, so feeding a later-maturity hay may be more appropriate for easy-keepers. 
Laminitis can be a devastating disease with long-term implications. However, with proper management, incidences of laminitis can be reduced in normal horses, as well as those predisposed to the disease. For more information, contact your local Co-op!