Sugars in grass and laminitis in horses

Spring is approaching, the days are getting longer, and most of us are looking forward to the warmer weather. However, for those who care for horses prone to laminitis, this can be a stressful time. Changes to pastures and increased availability of grazing raise the question: how much sugar are horses actually consuming from grass?

Let's take a closer look at what sugars are in grass and how their amount can change...

Sugars in grass – what you need to know

Sugars are naturally present in grasses. During photosynthesis, plants convert carbon dioxide into simple sugars in the presence of light. Therefore, the length of daylight and the presence of shaded areas in the pasture play a big role in the amount of sugar in your pasture.

When plants produce more sugar than they need for growth, they convert it into reserve carbohydrates - fructans. It is fructans, when ingested in large quantities, that cause an insulin response that can lead to laminitis.

Fructans continue to be produced even when their levels in the plant are already high, especially if conditions for photosynthesis are ideal but plant growth is slow. Fructan levels vary throughout the day: they are lowest in the morning, peak in the afternoon, and then slowly decline during the night.

How do fructans affect the occurrence of laminitis in horses?

It has been proven that large amounts of fructans can cause laminitis. Fructans are not digested in the foregut, but reach the hindgut, where they change the balance of the intestinal microflora. The increased production of lactic acid lowers the pH of the intestines, which can lead to disturbances in blood circulation and hoof inflammation.

That's why it's important to use digestive supplements that support a healthy gut microflora, especially in horses prone to laminitis. Probiotics and prebiotics help maintain a stable gut environment and increase resistance to nutritional challenges.

How does the environment affect the sugar levels in grass?

There are several factors that affect the sugar level in grass, and the variations are very large:

• Temperature – lower temperatures (5-10°C) increase fructan levels, while warmer weather (15-25°C) reduces their amount.

• Shade – shaded areas have half the sugar content of open pastures.

• Drought – lack of rain slows grass growth, but does not stop photosynthesis, which leads to the accumulation of sugars.

How much grass can a horse eat in a day?

The average daily grass intake is around 2.5% of body weight (dry matter), but some horses can eat up to 5.2%. This is why some horses and ponies develop laminitis on the same pasture, while others remain healthy.

If fructan levels are high and the horse eats quickly and a lot, hyperinsulinemia and hindgut overload can occur, which can trigger an attack of laminitis.

How to manage grazing in horses prone to laminitis?

Key prevention measures include:

• Graze in the morning – when sugar levels are lower.

• Using pasture masks – reduces the intake of stems, where sugar is higher.

• Avoiding grazing in low temperatures – especially if the grass is exposed to the sun.

• Providing alternative sources of fiber – quality hay or silage, preferably analyzed for sugar content.

The importance of a balanced diet

Restricting grazing and controlling sugar intake is a common practice for horses prone to weight gain or laminitis. However, when reducing feed intake, it is important to ensure adequate vitamin and mineral intake. Supplements designed for horses with endocrine disorders (such as EMS) can be a useful way to replenish nutrients.

If you have a horse prone to laminitis, plan its diet carefully and monitor its hoof health regularly. With the right approach, you can reduce the risk and ensure a quality life for your horse!