What Are ESCs?
ESCs (Ethanol-Soluble Carbohydrates) are simple sugars found in some horse feeds that can cause a rapid increase in blood sugar and insulin levels. They include sugars like glucose, fructose, and sucrose - all readily digested in the small intestine and responsible for rapid blood sugar spikes.
Feeds high in ESCs are a concern for horses with metabolic issues such as:
- Insulin resistance
- Equine Metabolic Syndrome (EMS)
- Cushing’s disease (PPID)
- Laminitis risk
What to Look Out For
ESC information is generally not shown on feed labels or websites, but you can easily assess the ESC risk by knowing where ESCs are found. Then you can avoid those ingredients and feeds if your horse is sugar-sensitive.
Feeds High in ESCs
- Cereal Grains: Corn, barley, and oats are high in starch and contain significant levels of simple sugars (ESCs). Corn, in particular, is very energy-dense and a major ESC source.
- Certain Grasses (Forages): Some cool-season grasses like ryegrass can accumulate high levels of simple sugars and fructans, especially when stressed (e.g. after sunny days followed by cold nights). This is why soaking hay is often recommended for sugar-sensitive horses - it leaches out water-soluble carbohydrates, including ESCs.
- Byproducts: Some grain byproducts from milling or alcohol production can also have higher ESC content.
ESCs are crucial when evaluating a horse’s glycaemic (blood sugar) response because they’re digested first - in the small intestine.
Why ESC Matters
Feeds high in ESC cause quick spikes in blood sugar. For some horses this can create serious health risks, while others may only need moderate control.
Horses that benefit from low-ESC feeds include:
- Horses with Equine Metabolic Syndrome (EMS) or Cushing’s/PPID
- Horses at risk of laminitis
- Horses with PSSM (a muscle disorder linked to sugar and starch)
- Overweight horses or “easy keepers”
By contrast, some performance horses may do well with moderate ESC levels if they need fast-release energy for hard work.
How Much ESC Is Acceptable?
Most quality low-GI feeds keep ESC below 10% of total dry matter. For therapeutic feeds, the target can be as low as 5–7%.
A little sugar for palatability doesn’t ruin the feed. For example, 2–3% molasses in a pellet helps bind and flavour the feed but has little effect on overall glycaemic load when the rest of the ingredients are fibre- or oil-based.
More Info on Ingredients and ESC Levels
High ESC Ingredients (>15%)
Avoid or use with extreme caution for sugar-sensitive horses:
- Cereal grains: corn, barley, oats, wheat
- Beet pulp with molasses
- Certain grass hays (especially ryegrass harvested after sunny days)
Moderate ESC Ingredients (10–15%)
Can be fed in moderation but should be monitored:
- Alfalfa (lucerne) and other legumes
- Soybean meal
Naturally Low ESC Ingredients (<10%)
Often used in low-GI feeds:
| Feed Component | Typical ESC Range | Benefits |
|---|---|---|
| Beet pulp (unmolassed) | 5–10% | High fibre, low sugar, safe energy |
| Soybean hulls | 3–7% | Excellent fibre, very low sugar |
| Alfalfa | 4–10% | Protein, calcium, moderate ESC |
| Flaxseed / linseed | 2–5% | Omega-3 fats, very low sugar |
| Rice bran | 5–9% | Fat for energy, moderate ESC |
Managing ESC in the Whole Diet
Because forage makes up most of a horse’s intake, managing ESC goes beyond choosing a bagged feed.
- Test your hay: Sugar levels vary widely.
- Soak hay: Can reduce sugars by 20–30% (results vary).
- Pasture timing: Grasses have higher sugar in the afternoon or when stressed by drought or frost.
- Exercise: Improves insulin sensitivity and offsets sugar intake.
- Body condition: Maintaining a healthy weight reduces metabolic stress.
Supplements like vegetable oil, balancer pellets and Vitamin E can provide energy and nutrients without adding sugar.
Key Takeaways
- ESC = the fast sugars in horse feed.
- Horses with metabolic issues, laminitis risk, or muscle disorders need low-ESC diets.
- Low-GI feeds usually keep ESC under 10%, sometimes down to 5%.
- Forage is the biggest factor — test and manage hay and pasture as carefully as bagged feed.
- A little molasses doesn’t ruin a feed, but undisclosed sugar levels can be a red flag.
Bottom line: Managing ESC is about balance. With the right mix of low-sugar fibre, oil for energy, and careful forage selection, you can control blood sugar spikes while keeping your horse well-fed and healthy.
Fiskens Nutritional Science
Fiskens feeds are formulated in collaboration with qualified equine nutritionists for optimal performance and balance. With over 60 years of expertise in equine nutrition, Fiskens is a trusted leader in developing scientifically backed feed solutions that support horse health and performance across all disciplines.