April's Showers Bring May's Laminitis
By Eleanor Richards

        Spring rains, warm temperatures and longer days trigger the growing season.  Pastures turn green and vegetation becomes lush.

        This can spell trouble for horses.

        Lush spring grass may lead to laminitis.

        Laminitis is the inflammation of the connecting tissues (sensitive laminae) between the hoof wall and the coffin bone.  If the inflammation is prolonged or severe the tissues die, allowing the coffin bone to rotate downward.  The rotation of the coffin bone results in a condition called founder.

        There are several causes of laminitis.  One cause can be the overload of non-structural carbohydrates in the large intestine. 

        The large intestine is designed to utilize structural carbohydrates.  The large intestine contains a balanced mix of microbes and protozoa which breaks down the hard-to-digest fiber (structural carbs) in forage.   

        The balanced environment within the large intestine can be disrupted by the introduction of large amounts of non-structural carbs.  Large numbers of the beneficial bacteria die and poisonous endotoxins are released into the bloodstream.  Blood flow to the hoof is restricted and the connective tissue (the laminae) between the hoof wall and coffin bone begins to die, resulting in laminitis.

       Forage is a good source of structural carbohydrates. But during certain times of the year there may be large amounts of non-structural carbs present in forage. Spring is one time of year.  Another is when rain starts after a drought and the grass begins to grow.

       When introducing any new feed the microbes in the large intestine need time to adjust to the change in diet.  This must take place slowly over of seven to 10 days.  If you want to be conservative - take two weeks.

       My method of introducing a horse to new pasture is to hand graze.  You'll find a horse on fresh green grass is difficult to catch. 

       I recommend filling the horse up on hay before allowing him to graze.

       I hand graze about 15 minutes a day for three days; 30 minutes a day for three days - increasing by 15 minutes every three days.  When the horse is up to an hour I'll let him loose and do something else while he grazes.  After an hour of grazing you can usually catch him.  I gradually work up to three hours a day.  (I am very conservative.)

        Once the horse is up to three hours he can be left out.  This, of course, depends on the condition and size of the pasture.  Good pasture management may not permit intensive grazing every day.

        Keep an eye on the horse's manure.  If it starts to become soft, reduce the amount of time he is being allowed to graze.  Wait until his manure returns to normal before increasing grazing time.

        Another consideration is the time of day the horse graze. 

        Generally, the safest time to graze a horse is in the morning - before the sun has pulled the sugars up from the roots. 

       But after a hard frost, which was preceded by a sunny day the non-structural carbs can be high.  The frost does not allow the sugars, which built up during the sunny day, to recede into the roots or be utilized by the plant. 
      Some horses should not be allowed grass or may only be allowed small amounts.  These horses may have Cushing's syndrome (PPID), may be insulin resistant, have a history of laminitis or have other metabolic problems. 

        If a horse has fat deposits along the crest and around the dock of the tail this may be a sign of a metabolic problem. Avoiding forage and other feeds high in non-structural carbohydrates is very important to the health of this horse.  This horse also needs to slim down.

       The addition of probiotics to the diet may help keep the microbes in the large intestine healthy and happy during the introduction of grass or a new feed. 

        With proper management we may prevent spring fever from turning into hot feet.

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