Founder and Lush, Spring Pastures

You’ve likely been cautioned before about allowing your horse to have access to lush pastures due to the fear of founder.  Maybe you have event experienced these problems yourself.  Let’s take a moment to discuss founder and lush forages.

Laminitis and Founder

Often times, the terms laminitis and founder have been used interchangeably.  However, they are not the same thing.  The laminae are the support structure within the hoof, between the hoof wall and the coffin bone.  Laminitis occurs when the laminae become inflamed and begin to separate from the coffin bone.  If the coffin bone becomes displaced or rotated, then founder has occurred.  Not all horses that experience laminitis founder, but all horses who founder have experienced laminitis. 

What do spring pastures have to do with anything?

A cause of laminitis is a diet with high levels of non-structural carbohydrates (NSC).  Lush, spring pasture growth is often higher in NSC than mature forage.  Cool season grasses, such as fescue, are more likely to accumulate NSC than warm season grasses, like bermudagrass.  NSC is also more likely to accumulate when forages stop growing or are experiencing stress.  With the up and down temperature patterns we have seen this spring, forages are going through periods of rapid growth followed by slow growth, which is likely to cause more accumulation of NSC.  Take steps to introduce spring pastures slowly.  You can find some good tips at http://msue.anr.msu.edu/news/managing_horses_on_spring_pastures.

Additionally, ponies, overweight horses, horses with cushing’s disease, or horses with a history of founder are more likely to have problems with laminitis and founder, so extra precautions should be taken.

You can find out more about laminitis and founder at https://www.clemson.edu/extension/publications/files/livestock-forages/lf10-laminitis-in-grazing-equine.pdf.