Carbohydrates, Starches and Sugars in Horse Feeds: What’s All the Fuss about NSCs?

Types of Carbohydrates in Horse Feed

Carbohydrates are an essential component of horse diets as they provide a valuable source of energy. When a horse consumes sugar, it is rapidly broken down into glucose and absorbed in the small intestine as part of the soluble carbohydrate fraction. However, if the sugar intake exceeds the horse's metabolic needs, it can pass undigested to the horse's hindgut, where it can disrupt the microbial balance and potentially lead to digestive or intestinal upset. There are two primary types of carbs: structural and nonstructural. Structural carbs, such as cellulose and hemicellulose, are found in the cell walls of plants and cannot be digested by horses because they lack the necessary enzymes. 

On the other hand, nonstructural carbs (NSC) can be digested and used by horses for energy. NSC include simple sugars, starches, and fructans. Simple sugars, such as glucose and fructose, are absorbed directly into the bloodstream and can cause a rapid rise in blood glucose levels, also known as glycemic response.

Starches must be broken down into simple sugars by enzymes in the small intestine before they can be absorbed. Monosaccharides such as glucose, amino acids, and fatty acids are absorbed in the small intestine. This process results in a slower glycemic response than simple sugars. However, if too much starch is consumed at once, it can overload the GI tract and lead to undigested starch entering the large intestine, where it can be fermented by microbes.

Fructans are a type of sugar found in cool-season grasses and can also be fermented in the large intestine. Fermentation of undigested carbs can result in an increased production of lactic acid, which can lower the pH of the large intestine and potentially lead to colic and founder.

Glycogen is another type of carbohydrate that is stored in muscle tissue and used as an energy source during exercise. Blood glucose levels can be maintained during exercise by the breakdown of glycogen stores in the muscles.

Overall, understanding the different types of carbohydrates and their effects on the horse's digestive system is crucial in designing a balanced diet that meets the horse's energy requirements without negatively impacting their health.

Structural Carbohydrates

Structural carbohydrates are complex carbs that provide support and structure to plants, and include cellulose, hemicellulose, and lignin. Unlike nonstructural carbs, which can be easily digested by the horse's digestive enzymes, structural carbs cannot be broken down by the enzymes in the horse's GI tract.

Structural carbs are important for horses because they help maintain healthy digestive systems and promote proper gut function. When horses consume forage (hay and grass in the pasture) they are taking in both nonstructural and structural carbs. The nonstructural carbohydrates are quickly broken down and metabolized- providing the horse with energy, while the structural carbs are fermented in the hind gut by the microbiota, and release short chain fatty acids which do enter the metabolism of the horse but not into carbohydrate metabolism. Instead, they go into fat metabolism.

Structural carbs play an important role in maintaining a healthy metabolic conditions- the presence of structural carbs in the horse's diet helps to regulate the intake of nonstructural carbs, and they also help with the release of glucose into the bloodstream. This can help to prevent spikes in blood glucose levels which can lead to metabolic problems and diseases such as IR.

One type of structural carbohydrate that has received a lot of attention in recent years is fructan which is a complex carbohydrate found in certain types of hay and can be difficult for horses to digest. When fructan reaches the hindgut, it can be metabolized by microbial fermentation, producing lactic acid. This can lead to a decrease in pH levels in the hindgut which can cause digestive upset (minor colic incidents) and other health issues in horses.

Overall, while structural carbohydrates are not directly metabolized by the horse, they play an important role in maintaining healthy metabolism and promoting proper gut function. By including a variety of forages in a horse's diet, horse owners can help to ensure that their horse is getting an appropriate balance of both nonstructural and structural carbs.

Non-Structural Carbohydrates

Non-structural carbohydrates (NSC) refers to the readily available sources of carbs in horse feeds- including sugars and starches. NSC content is the total amount of these carbs in a feed. It's essential to monitor NSC levels in the diets of performance horses, those with conditions like equine metabolic syndrome (EMS), and horses prone to founder.

Sugars and starches are the primary sources of energy in horse diets, but excessive amounts can be problematic. High levels of NSC can cause a rapid surge in blood glucose and insulin levels. That's why it's crucial that we select feeds with controlled starch and sugar levels for horses prone to these conditions.

Hard working horses require adequate energy to meet their daily needs and are often fed grains that are higher in nsc, but overfeeding them can lead to nervous behavior and decreased performance. Metabolically, nonstructural carbohydrates play a crucial role in providing energy to horses. It's important to choose feeds that meet the energy requirements of these horses while keeping NSC levels in check.

In summary, monitoring NSC levels in horse feeds is vital to maintain healthy and optimal performance. Horses with conditions like EMS require diets with lower NSC levels, while working horses need an appropriate amount of carbohydrates to support their energy needs. Careful selection of feeds with controlled starch and sugar levels can help prevent health problems associated with high NSC intakes.

Low- NSC Horse Feeds: What Kind Does My Horse Need?

How Much NSC Does My Horse Need in Its Diet?

When it comes to the NSC requirements there is no one-size-fits-all answer. The ideal value will depend on your horse's individual needs and metabolic condition.

For most horses, the value should be kept below 20%, with a target range of 10-15%. Performance horses may require slightly higher NSCs to support their increased energy needs, but it's important to work with a veterinarian or equine nutritionist to determine the appropriate level for your horse.

Horses with EMS should have an even lower NSC content in their feed, typically below 10%. Additionally, horses with a history of founder may need a nutrition plan that is very low in NSC, usually around 10% or less.

There are many factors that can impact NSC levels in a horse's diet, including the type and amount of hay, the type and amount of concentrate feeds, and the feeding schedule. Choosing feeds with controlled starch and sugar content can help you manage your horse's NSC intake and ensure they stay healthy and happy.

We recommend working with your equine nutritionist to determine the appropriate NSC content for your horse's diet. By carefully managing your horse's NSC intake, you can help prevent a variety of health issues and keep your horse performing at their best.

Identifying High- Risk Equines

Horses with Cushing's disease, also known as pituitary pars intermedia dysfunction (PPID), typically require low NSC meal plans. PPID horses have an overactive pituitary gland that can cause a variety of symptoms, including IR, laminitis, and abnormal fat deposits. A low NSC diet can help manage these symptoms by reducing the horse's exposure to simple sugars and starches, which can exacerbate IR and increase the risk.

Horses with PPID may also have increased sensitivity to fructans, a type of carbohydrate found in certain grasses. Fructans can accumulate in the grass when temperatures fluctuate, particularly during the spring and fall. Grazing on fructan-rich grass can trigger founder in susceptible horses, so it's important to manage their access to pasture carefully.

IR and EMS are common in many types of equines, including ponies, miniature horses, Morgans, Paso Finos, Arabians, and Warmbloods. However, any breed or type of horse can develop IR or EMS, and it is not always easy to predict which horses are at risk. Factors such as age, gender, body condition, and diet can all play a role in the development of these conditions. It is important for horse owners to be aware of the signs and symptoms of IR and EMS and to work with a veterinarian and equine nutritionist to develop an appropriate management plan for at-risk horses.

The signs and symptoms of these conditions can vary, but some common indicators include:

1. Abnormal fat deposits particularly around the neck, shoulders, and tail head.

2. Laminitis

3. Abnormal sweating

4. Changes in appetite and weight

5. Lethargy and poor performance

6. Abnormal (higher) insulin and glucose levels

Laminitis Prone Horses

As an equine nutritionist, I often receive questions from concerned horse owners about the impact of NSC on their laminitis-prone horses. Laminitis is a painful and potentially debilitating condition in horses that involves the inflammation and damage of the laminae, which are the sensitive tissues that connect the hoof wall to the coffin bone.

Research has shown that a meal plan high in NSC, particularly sugars and starches, can increase the risk of founder in susceptible horses. When horses consume high amounts of NSC, it can cause rapid fermentation in the hindgut, leading to an increase in lactic acid production and a decrease in pH. This shift in gut pH can result in the death of beneficial microbes and the proliferation of harmful bacteria, which can lead to endotoxemia and systemic inflammation.

These horses require a nutrition plan that is low in NSC, with a recommended maximum of 10-12% NSC. Performance horses, on the other hand, may require a higher NSC diet to fuel their exercise and performance. However, it is important to note that the NSC value of a feed does not necessarily indicate its impact on blood glucose and insulin levels, which can also play a role in laminitis development.

To minimize the risk of laminitis in susceptible horses, it is important to carefully monitor their intake and ensure that they are receiving a balanced food program that is appropriate for their metabolic condition. This may involve feeding a controlled starch and sugar regimen, soaking hay to reduce NSC content, and providing access to pasture with controlled grazing to limit NSC intake.

IR/ EMS Horses: Insulin Resistance

IR stands for insulin resistance, which is a metabolic disorder where the body's cells become less responsive to insulin, resulting in high levels of glucose in the bloodstream. This condition can lead to a range of health problems..

EMS, or equine metabolic syndrome, is a collection of risk factors for developing IR. These risk factors include obesity, abnormal fat distribution, and high levels of non-structural carbohydrates in the nutrition plan. Horses with EMS are at an increased risk of developing IR and subsequently, founder.

Managing the NSC intake of horses with EMS is critical to reducing their risk of developing more serious issues. It is important to work closely with a veterinarian and equine nutritionist to develop an appropriate nutrition plan and exercise program for these horses. Additionally, regular monitoring of blood glucose and insulin levels can help detect early signs of IR and allow for timely intervention.

How to Calculate the NSCs in Horse Feed

NSC Levels in Grain 

Not all grains have the same level of starches and sugars. Oats, for example, have a low starch and sugar content compared to corn, which has a higher value. It's also important to remember that other factors, such as the processing and cooking of the grain, can affect the percentage. 

Calculating the NSCs in grain can be done by adding the percentage of simple sugars (glucose and fructose) to the percentage of starch in the feed. The NSC value is the sum of the two percentages. For example, if a grain feed contains 20% simple sugars and 40% starch, the NSC value would be 60%.

To ensure accuracy in calculating the score, it's recommended to send a sample of the feed to a laboratory for analysis. Lab tests provide detailed information on the specific content of the feed, which is particularly important for horses with special dietary needs, such as those with IR or EMS.

NSCs in Forage

Hay and pasture grass serve as important sources of energy in a horse's diet. Calculating the NSC content of hay involves measuring the levels of sugar, fructan, and starch in the sample. It is easiest to collect a representative hay sample and send it in to your local extension cooperative or Equi-Analytical in New York for testing (we are not affiliated with them). It is essential to collect a sample that represents the entire hay batch, so take several samples from different bales and areas of the stack and mix them together if you need to. 

Calculating pasture plant's NSC levels can be a bit more complicated than in hay or grain, as the NSC levels can vary depending on the time of day, weather conditions, and other factors.

NSCs in grass are typically highest in the afternoon and evening hours, as photosynthesis continues to produce sugars during the day and the plants continue to store them overnight. Additionally, NSCs tend to be highest during the spring and early summer when grass is rapidly growing and producing new leaves. As the grass matures and enters the late summer and fall, NSCs tend to decrease as the plants store energy in their roots for winter dormancy.

How to Reduce NSCs in Your Horse's Diet

How to Choose Horse Feed with Controlled Starch Feed Ingredients

When it comes to horse feeds, controlled starch feed ingredients are becoming increasingly popular. These feeds are designed to provide a more balanced and controlled source of energy for horses than grains higher in NSCs, while minimizing the risk of spikes in blood sugar levels. Some common controlled starch feed ingredients include beet pulp, soybean hulls, and rice bran. These ingredients are often used in combination with other low NSC hay sources, such as Timothy hay, to create a balanced nutrition plan that meets the horse's nutritional needs without overloading them with excess sugars and starches. Overall, controlled starch feed ingredients can be an effective tool for managing a horse's NSC intake and maintaining their metabolic health.

Grain: Finding Low Starch & Sugar Feeds

As an equine nutritionist, I often recommend low-starch and sugar grain for horses with specific health conditions or performance needs. These types of feeds can be helpful in reducing the horse's overall starch intake and promoting healthy digestion. If you're looking for low-starch and sugar grain, here are some things to keep in mind:

1. Check feed labels: Many feed manufacturers now include NSC values on their feed labels. Look for feeds that are specifically labeled as "low-starch" or "low-sugar" to ensure you're choosing a suitable product.

2. Look for feed ingredients: Some feed ingredients are naturally lower in NSC, making them a good choice for horses that require special care. These include beet pulp, soy hulls, and alfalfa meal. Avoid feeds that list corn, barley, or molasses high up in the ingredients list.

3. Understand NSC in the hindgut: Not all NSC is digested in the horse's foregut. Some can pass through to the hindgut, where it can cause problems for horses with certain conditions. Look for feeds that are designed to be low in NSC in both the foregut and hindgut.

4. Consider your horse's specific needs: Horses that are IR, have laminitis, or require a low-starch nutrition plan for other health reasons will have different requirements when it comes to NSC intake. Consult with your veterinarian or an equine nutritionist to determine what type of feed is best for your horse.

Reducing Sugar & Starch in Forage: Using Hay Steamers and Soaking

Hay is an essential component of any equine diet and is an important energy sources, so it's essential that the hay you are feeding is suitable for your horse's needs. One crucial factor to consider when selecting hay is its NSC content. NSC stands for nonstructural carbohydrates, which include simple sugars, fructans, and starch. High NSC content in hay can be problematic for horses that are IR or have other metabolic conditions.

Here are some tips on how to reduce NSCs in hay:

1. Choose the right type of hay: Some grasses, such as timothy and orchard grass, tend to be lower in NSCs than others, like bermudagrass or fescue. Legume hay, such as alfalfa, tends to be higher in NSCs than grass hay, so it may not be the best choice for these horses.

2. Harvest at the right time: The stage of growth at which the hay is harvested can impact its NSC content. 1st cut (early-cut) hay generally has a lower NSC content than 2nd or 3rd hay, which tends to be higher in sugars and starch.

3. Soak the hay: Soaking hay can help reduce its NSC content. By soaking hay in water for 30 minutes to an hour, some of the sugars and starch can leach out into the water.

4. Use hay steamers: Hay steamers are another option for reducing the NSC content of hay. By steaming hay for 60 to 90 minutes, sugars and starch can be reduced by up to 30%.

5. Combine hay with other forages such as hay cubes or beet pulp, can help reduce the overall NSC intake.

6. Consider testing hay: If you are unsure about the NSC content of your hay, consider having it tested. Testing can provide you with valuable information on the sugar & starch levels in your hay, allowing you to make informed decisions about your horse's diet.

Limiting Sugar & Starch Intake in Pasture Forage

Many horses receive the bulk of forage in the diet through pasture grasses- especially during summer months. Reducing NSCs in pasture grasses is crucial for horses that are sensitive to sugar & starch, such as those with IR or founder. Here are some tips on how to reduce NSCs in pasture grasses:

1. Timing: NSCs in grass tend to be highest in the early morning and late afternoon. To reduce your horse's NSC intake, limit grazing during these times, and instead offer hay or other low-NSC forage.

2. Mowing: Regular mowing removes the tips of the grass blades, which tend to be higher in sugar. Mowing can also encourage regrowth of lower-sugar grasses.

3. Fertilization: Avoid over-fertilization with nitrogen.

4. Grass species: Some grass species are naturally lower than others. Fescue, orchard grass, and timothy are generally lower in NSCs than Bermuda or ryegrass, for example.

5. Soil health: Maintaining healthy soil can lead to healthier, lower-sugar grasses. Testing soil pH and nutrient levels and making appropriate adjustments can help.

6. Grazing management: Implementing rotational grazing can help reduce NSCs in pasture grasses by allowing them time to regrow and reducing overgrazing.

Remember that forage should always make up the majority of a horse's diet, so it's important to choose low-NSC forage options and manage pasture grasses accordingly to ensure your horse's metabolic health.

Conclusion 

I hope this blog post has been helpful in explaining the importance of monitoring NSC levels in your horse's diet. By understanding the different types of carbohydrates and their effects on equine health, you can make informed decisions about the feed your horse gets. While not every horse needs a low NSC diet in order to maintain good health, those of you with metabolic concerns should take care in finding the right grains and forage feed for your horse. Whether you have a horse with IR or EMS or are simply concerned about maintaining optimal health, keeping NSC levels in check is key. So next time you're selecting hay, pasture grass, or grain, be sure to pay attention to the NSC contents listed on the feed label or consider testing the forage. 

If you have questions about feeding horses or horse health, feel free to reach out to us for a nutritional consultation.