The Dangers of Spring Time Grass

Are you aware of the dangers of Spring time grass?

For those who live in climates where the seasons are well defined, spring time is a wonderful season where the flowers start blooming, the trees start getting their buds and growing leaves, and the grass and vegetation start to get vibrant and green. While the color ushers in the end of a long cold winter and the beginning of long-awaited warmer weather, it also ushers in yet another concern for horse owners.

The Science Behind Spring Time Grass

According to an article from, spring pasture grasses are capable of accumulating high amounts of nonstructural carbohydrates (NSCs). The types of NSCs found in grasses fall into three categories: sugars (glucose, fructose, sucrose), starches, and fructans.

The NSC content of grass varies widely depending on environmental conditions, plant species, and stage of growth. Through photosynthesis, grasses use light to produce sugars from carbon dioxide. When sugars are produced in excess of the plant’s energy needs for growth and development, they are converted into storage, or ‘reserve,’ carbohydrates.

Fructans are the primary storage carbohydrate in cool-season grasses (tall fescue, orchardgrass, and timothy). Cool-season grasses can accumulate higher amounts of carbohydrates because they store their fructans outside of the chloroplast (the part of plant cells that conducts photosynthesis) in vacuoles that don’t limit their storage.

In the spring, cool-season grasses are the main concern for horses because the grass is growing rapidly and environmental conditions favor NSC production.

Read More Here…

So in short, spring time grass is very high in Carbohydrates in the form of sugars and fructans, and lower amounts of Fiber.

As we all know, the new addition of lush grass in pastures is irresistible to our horses, especially those who have been on a diet of sparse pasture and hay all winter.

Common Problems associated with Spring Grass

The most common problems associated with spring time grass include behavioral issues, weight maintenance, stomach upset, and development of insulin resistance and/or laminitis.

Behavioral Issues

Ever notice your horse is a little more high strung, spooky, feisty, harder to handle in the Spring? Most likely it can be contributed to the spring grass. Think if a child who has had too much candy…they’re bouncing off the walls. Well, the same can be said for horses on spring grass. So you may need a little more patience and courage when riding your horse in the spring.

Stomach Upset

The extreme change in diet with the increased carbs and sugars can easily upset the populations of microorganisms in the intestinal tract, especially the large bowel. Early signs that your horse may be getting too much green grass and is headed for intestinal upset is softening of the manure. More serious upset includes bloating, worsening diarrhea, and even colic. In the worst-case scenario, large amounts of rapidly fermented sugars can cause sufficient acidity in the large bowel to damage the wall, allowing bacterial products to penetrate into the bloodstream in sufficient amounts to cause laminitis (discussed more below)

Weight Maintenance

Horses can be at risk for weight gain on spring grass. It’s very easy for horses to overeat and gain dangerous amounts of weight. Just like humans, too much weight on a horse can lead to health issues such as increased strain and pain on the horse’s feet, joints and heart.

Insulin Resistance and/or Laminitis

Insulin Resistance and Laminitis are by far the most dangerous potential consequence of turnout on spring pastures in terms of pain and potential long-term consequences.

I talked about Insulin Resistance and the high number of cases found in Gaited Horses in a previous article:

According to the RSPCA, Laminitis, also referred to as Founder, is the inflammation of the laminae of the foot - the soft tissue structures that attach the coffin or pedal bone of the foot to the hoof wall. The inflammation and damage to the laminae causes extreme pain and leads to instability of the coffin bone in the hoof. In more severe cases it can lead to complete separation of and rotation of the pedal bone within the hoof wall.

Laminitis is a crippling condition which can be fatal in severe cases. Once a horse has had an episode of laminitis, they are particularly susceptible to future episodes. Laminitis can be managed but not cured which is why prevention is so important.

Picture Reference

Initial (acute) symptoms of Laminitis

  • Although all four feet can be affected, the forelimbs are more frequently and more severely affected than the hindlimbs
  • Affected horses are reluctant to move and adopt a 'sawhorse' stance where they rock their weight back off the more badly affected forelimbs
  • Laminitic horses will often lie down
  • It will be difficult for you to pick up one forelimb due to the severe pain of the other supporting forelimb
  • The hoof wall and coronary band (the soft tissue around the top of the hoof) are often warm to touch
  • There is often pain on application of hoof testers (a tool your vet or farrier uses to assess hoof pain) – particularly over the toe area
  • Digital pulses are strong and rapid (the digital pulse is found at the back of your horse’s fetlock). If you are uncertain how to check this, ask your vet to demonstrate.

Read More…

Prevention of Spring Grass-Related Issues

Thankfully, there are ways to prevent problems related to over ingestion of spring grass.

Most commonly, Grazing Muzzles are used to allow pasture kept horses to still enjoy some forage without completely blocking their intake of the fresh new grass. There are many options and sizes available, so it’s a good idea to shop around and determine which would be the right one for your horse.

Here are some options that are available on Amazon.

Picture Reference.

Limited turnout may be an option for those who have access to a stall to keep their horses in for a larger part of the day.

Dry lots (containment areas without any grass at all) are an option in extreme cases where it’s been determined that your horse should not have any grass due to new or pre-existing conditions. However, in these cases, alternate forage such as Hay must be provided.

Or, in some extreme cases, farm owners may choose to re-seed their pastures to plant more horse-friendly grass. This article from Calm Healthy Horses provides some great information on what types of grasses are considered hores-friendly and how to re-seed your pasture.

The important factor here is education and observation.

Keep a close eye on your horse during Spring to make note of any issues which may arise with the new season. If you notice any of the symptoms arising as outlined above, you may need to consider limiting your horse’s grazing until the warmer weather sets in and the carbs and sugars in the grasses settle down.

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