Introducing Your Horse to Grass Pasture

In the springtime, every horse owner sees the lush green grass with their horses' eyes and is eager to turn their horses out to pasture.  

However, did you know that too much spring grass can make your horse lame due to laminitis (aka grass founder)?

Laminitis is the inflammation of the sensitive laminae which are folds inside the hoof wall that attach to the bone inside the foot. The laminae can be inflamed by ingestion of fructan or non-structural carbohydrates (NSC), the sugar found in fresh grass.

View of the laminae inside the hoof capsule

Managing Your Grass Pastures

There are a variety of factors that influence the amount of sugar found in the grass (or grass hay for that matter).  

Temperatures at night below 40 degrees and sunny weather both contribute to high sugar levels which is why laminitis is more common in the spring and fall. 

Time of day is also a factor as sugar levels tend to be higher in the late afternoon and evening. 

Although at first it is counter-intuitive, not using enough fertilizer can contribute to higher sugar levels. This is because fertilizer contains nitrogen and if the grass is deprived of nitrogen it can't convert sugar into growth so the sugar levels continue to rise.  

It can also help to manage weeds like dandelions and thistles, which tend to be high in sugar and are very palatable to horses. Controlling the weed population on your horse property allows grass to be the predominant plant.  

Mowing the grass also helps to limit sugar content as grass seeds which grow at the top of grass blades are higher in sugars. It's best to keep grass at 4-8" tall so if you can rotate your horses to another pasture and mow as necessary.

Risk Factors in Horses

Some horses are more prone to developing laminitis than others.  Any horse who has previously foundered or had laminitis for any reason is at a greater risk of developing it again. 

Overweight horses or horses with Equine Metabolic Syndrome (EMS) are susceptible to laminitis due to insulin resistance and sensitivity to sugar levels in their grass or hay.  Signs of EMS include a cresty neck and fat deposits on either side of the tail head. 

Horses with PPID (aka Cushing's Disease) are also at a greater risk for grass founder. Signs of Cushing's Disease include not shedding out in the spring and developing long hairs on the legs and the entire body. 

Horse with tell-tale Cushing's coat

Additionally, any horse who has not had high sugar-content hay or fresh grass all winter is at greater risk unless introduced slowly.

How to Introduce Your Horse to Grass

If you want your horse acclimated to grass, you have to gradually introduce them to it over a period of about 2 weeks. Begin with 15 minutes of grazing on the first day.  You can then increase to 30 minutes the next day and so on. 

My mare, Elena - notice the fat deposits around her tailhead & her cresty neck.  While she's never foundered, she's overweight & at risk.

Look for your horse's necks hardening, any heat in their hooves, and any tenderness when doing a brisk trot on hard ground.  

Some horse owners use grazing muzzles on their horses to limit how much grass they can consume at a time which can also prevent grass founder.

A grazing muzzle

Regular exercise also is a great preventative as it keeps your horse fit and burns those sugars your horse is consuming.  

Horses love grazing and it is natural for them to have the constant movement and chewing involved, but some management is necessary to prevent grass founder.

Looking for a hobby farm with grass pastures to call your own so you can take care of your horses' needs? Look at www.donavin.com or www.mnhorseproperties.com for horse properties for sale in the Twin Cities metro area of Minnesota.