Picking Hay for Sugar/Starch Sensitive Horses

All horses need fiber in their diet and some of it must be the form of long hay. Horses challenged by metabolic syndrome should be offered hays that are low in non-structural carbohydrates or NSC. This class of carbohydrates includes starch, water-soluble sugar, and fructan.

Normal horses can tolerate NSC levels of 20% or higher. It is recommended that horses with metabolic syndrome consume hay with NSC levels of around 10% to 12%.

In order to know the true NSC value of your hay you will have to test it, but understanding the factors that affect NSC levels will help you pick a hay that is more likely to meet your horse’s needs. Several factors affect the NSC levels found in a cutting of hay. Multiple cuttings from the same field of grass can yield hay with different levels of NSC. The type of plant, maturity when harvested, time of cutting, time spent curing in the field, and environmental conditions during harvest all contribute to the amount of NSC found in the plant. When choosing hay for a starch/sugar sensitive horse, you have to consider all these factors.

Type of plant:

Typical NSC levels in different types of hay*

  • Grass hays: average of 12% (range 7%-18%)
  • Legume hays (alfalfa and clover): average of 15%
  • Oat hay: average of 22%

*Values from Equi-analytical Laboratories.

Maturity of plant

  • Young plants tend to be higher in sugar
  • Mid-bloom, mature grass tends to be lower in sugar
  • Very mature plants tend to contain large amounts of indigestible fiber and can be unpalatable

Timing of harvest and curing conditions

  • Grasses harvested in the morning, following evenings when temperatures are 40°F or above will be lower in NSC
  • The longer hay is dried in the field, the lower the NSC
  • Western hays tend to be harvested later in the day and baled more quickly than Eastern hays, so they can be higher in NSC
  • Hay that has been lightly rained on will be lower in NSC; however, it must be completely dry when baled or it will become moldy

Environmental conditions at harvest time

  • Grasses stressed from drought conditions or freezing temps will contain higher percentages of NSC
  • Stressed warm season grasses, such as crabgrass or coastal Bermuda grass, tend to be lower in NSC
  • Stressed cool season grasses, such as fescue, orchard grass, and timothy, tend to be higher in NSC

Hay analysis

The best way to determine the NSC value in a bale of hay is get it tested. When you test your hay you get not only the NSC value but other nutrient levels as well. There are several laboratories that specialize in hay analysis. Equi-analytical Laboratories has a 6-step procedure in diagram form on their website. You can also check with your local extension office to see if they offer testing services.

Plan on collecting a sample for each load of hay you purchase. To collect your sample you will need a hay probe, a drill, and a zip lock sealable plastic bag to put the sample in. You can either purchase a hay probe or you can check with your local extension office to see if they can loan you one.

To sample your hay, pick 12 to 20 random bales from throughout the load. Probe each bale in the center of the strings on the small end of the bale so you are probing the length of the bale. Put each sample in the bag and mix well. Fill out the paperwork required by the testing facility and drop it in the mail. Once you receive your results, if you have any problems understanding them don’t hesitate to contact the lab or your local extension office for help.

At some point, most of us will have to manage a starch/sugar sensitive horse. Understanding the need to tailor a diet to meet his or her needs will make your life easier and your horse happier.



  • Caitlyn Henderson

    Howdy! In winter in Texas, our usual coastal bermudagrass hay tends to run out pretty much everywhere. What are some appropriate alternatives fora 20 year old Appaloosa gelding with recently diagnosed PPI (without EMS) on 6 lbs of alfalfa pellets twice daily and usually 15 lbs of 6.2% NSC coastal bermudagrass hay per day?

    • Karen @ KPP

      Just to clarify, your horse has PPID (Cushing’s disease) but he is not sugar sensitive (insulin resistant), is that correct? If so, then there are many alternative fiber options on the market. Most of the them have an NSC value of 12% or less, which is appropriate. If he becomes insulin resistant, then you need to look for NSC values that are 10% or less.

      Grass hay cubes, compressed grass hay or grass hay chop are all appropriate alternatives. Whatever you choose, make sure it is dust-free and mold-free and that there is a consistent supply available.

      Start to add your alternative fiber source into the diet slowly, before you run out of hay. This will allow your horse’s digestive tract to adjust to the new feed. Plan on a switchover period of 10 to 14 days. Depending on the quality of the fiber source you choose, you will mostly likely replace the hay pound for pound. Offering smaller meals more often is ideal. Monitor your horse’s weight and adjust the amount fed accordingly.

      Since your horse is older, if you choose to feed hay cubes, soak them before feeding. I like to add enough water so that the cubes are just floating. Let them sit for 30 minutes, or until all of the water is absorbed, because it makes them easier to chew.

      Nutritionists recommend including some long hay in the diet to reduce boredom and increase chew time, so consider feeding at least some fiber alternative year-round to stretch your hay supply so you don’t run out.

      Most feed companies keep a grass hay cube in stock. Some carry hay chops. Make sure the hay chop you get meets your NSC requirement of 12% or less. It is okay for hay chop to have some molasses in it as long as the overall sugar levels remain low. Insulin-resistant horses should consume feeds that are 10% or less NSC.

      I would also highly recommend adding a vitamin and mineral pellet such as Micro-Phase (http://kppusa.com/product/micro-phase) to your horse’s diet to ensure he is getting all the vitamins and minerals he needs to stay healthy.

      Additional vitamin E, up to 3,000 IU per day, is beneficial for horses struggling with PPID. It supports a strong immune system and helps maintain healthy muscle and nerve functions. For best results, choose Elevate® Maintenance Powder. (http://kppusa.com/product/elevate-maintenance-powder)
      You can also add some unsweet beet pulp to the diet, but you don’t want to feed more than 3 lbs a day. Here is a good article with information about how and why to feed beet pulp. (http://kppusa.com/2014/12/19/beet-pulp-super-hero-fibers)

      Standlee Hay (https://standleeforage.com) offers a variety of grass hay cubes and compressed baled hay that would be appropriate. They have a chart on their website that gives the NSC value for each type of fiber product they sell. https://standleeforage.com/nutrition/nutritional-papers/low-carb-forage-options

      Triple Crown Safe Starch Forage is another option. This a fortified hay chop. https://www.triplecrownfeed.com/products/safe-starch-forage Or they have an unfortified option as well, Triple Crown Premium Grass Forage https://www.triplecrownfeed.com/products/grass-forage

      If you have additional questions, please let us know.

      Karen at KPP

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  • janet mckinney

    My vet recommended that I switch from orchard grass to timothy because my gelding was becoming to heavy. We drew blood and he had slightly elevated sugar levels, normal thyroid, and normal everywhere else. My difficulty is I am very allergic to timothy hay. I am also extremely sensitive to bermuda. Pellets have been suggested but I am concerned about fiber. Two nights ago he had a mild colic episode. We suspect the cause being the weather. In addition to 5 lbs hay he gets 1 lb. Purina Enrich per feeding and a scoop of StressDex electrolyte.
    Can you make any recommendations to keep my horse trim and still allow me to breathe normally?

    • A horse should be consuming 1.5% to 2% of their body weight in fiber (hay, pasture, cubes or pellets) per day. That is 15 to 20 lbs for a 1,000 lb horse. Make sure you are feeding adequate levels of hay to support a healthy digestive tract. If your vet feels the orchard grass hay you are feeding is providing too much sugar or too many calories, it is smart to change hay; however, when choosing a hay I would recommend you depend on the nutrient profile of a hay instead of simply the type of hay.
      Orchard grass and timothy have similar nutrient profiles, so you might be able to find an orchard grass hay with lower sugar levels that provides fewer calories than what you are currently feeding. Have your hay tested and pay close attention to the levels of NSC (nonstructural carbohydrates, or sugars), CF (crude fiber) and DE (digestible energy, or calories). Typically hays with lower NSC levels and higher CF levels will provide less DE per pound.
      A more mature orchard grass could provide your horse with what he needs and allow you to keep breathing! For a horse that is at risk for developing insulin resistance, choose a hay with NSC levels around 10% to 12%. For hays with higher NSC levels you can soak the hay for 15 to 60 minutes to reduce the sugar levels. Here is a link to a great hay testing lab, Equi-Analytical. The website even walks you through how to properly take a sample. http://equi-analytical.com

      As far as feeding hay cubes or fiber pellets, there is some controversy regarding optimum fiber length requirements in the horse’s gut. As long as you feeding an adequate amount of fiber, and some long hay (recommendations range for 25% to 50%) along with cubes or pellets, your horse will probably do fine. Cubes can be fed dry or soaked, depending on your preference; however, soaking them is a great way to increase water intake. Feed several small meals per day to give your horse plenty of chew time, as this will reduce both boredom and the risk of ulcers.

      To reduce the risk of colic make sure your horse is drinking adequate water. A good electrolyte will stimulate the thirst response and increase water intake. StressDex is 73% sugar and only 1.9% salt. I suggest you choose a supplement that provides more electrolytes and less sugar. Compare StressDex to Summer Games Electrolyte as an example. https://kppusa.com/all-products/summer-games-electrolyte/ingredients/#begin_content

      Make all feed changes (both hay and grain) very slowly, over 10 to 14 days. Research has shown that it takes two weeks for the equine gut to acclimate to new feedstuffs. When quick changes occur the risk of colic increases dramatically.

      All best,

      • Diane

        Thanks for info. Transitioning to feeding older horse with poor teeth and laminitis issues has been a challenge. Appreciate the info.

  • peggy vurgason

    Is a horse at less risk for laminitis on grass as opposed to other grasses? We recently moved to FL from NJ.
    My horse is a candidate for laminitis. In NJ we had very little grass in our turn out. Here in FL the pasture is Bohemian grass. I muzzle him most days- depending on the weather. Am I doing what is best for my horse?
    Please advise,

    • Hi Peggy,

      Unfortunately, I can’t find any specific information on Bohemian grass. Many of the pastures in Florida are made up of mostly warm-season grasses that perform well in hot, humid conditions; however, some cool-season grasses can also be present to provide winter grazing.

      In general, warm-season grasses contain less sugar then the cool-season grasses found in the northern states, but keep in mind all grasses contain some sugar. The level of sugar is dependent on species of grass, time of year, and growing conditions. To find out more about the specific grasses in your pasture, contact your local Ag Extension agent or the Animal Science program at the University of Florida in Gainesville.

      If you have a horse that is susceptible to laminitis, it is always best to restrict the amount of fresh grass they consume, so you are on the right track. If you have concerns, don’t hesitate to contact your local veterinarian and ask questions. Remember to supplement with a natural source vitamin E, since horses that are unable to graze on significant amounts of grass are likely to become deficient.

      I hope this helps.

      Karen Isberg
      Kentucky Performance Products, LLC

  • Trisha Nieman

    This is a very important topic. I recently had to put down my 29 year old Appaloosa Gelding. He was my childhood horse – 25 years! I knew Shammie inside & out. When he started showing signs I started reading to have more awareness on the subject. I am thankful for these types of articles! THANK YOU!!

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