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 costal 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.


Article written by KPP staff.

Copyright (C) 2012 Kentucky Performance Products, LLC.   All rights reserved.

Article sponsored by Elevate Maintenance Powder; an affordable, easy way to provide essential natural vitamin E, when longer-term vitamin E supplementation is needed.

When health issues arise, always seek the advice of a licensed veterinarian who can help you choose the correct course of action for your horse. Supplements are intended to maintain healthy systems and support recovery and healing. They are not intended to treat or cure illness or injury.

About Kentucky Performance Products, LLC:

Since 1998, Kentucky Performance Products has simplified a horse owner’s search for research-proven nutritional horse supplements that meet the challenges facing modern horses. KPP horse supplements target specific nutritional needs and are formulated to complement today’s feeds, thus safeguarding against over-supplementation. Each product is scientifically formulated and made with high-quality ingredients at certified manufacturing facilities. Kentucky Performance Products is proud to offer a quality assurance promise backed by a money-back guarantee. Kentucky Performance Products brings you horse supplements you can count on because the horse that matters to you, matters to us.

Category : Fat & Fiber | Tips and Topics


  1. [...] From the Kentucky Performance Products blog: [...]


  2. Trisha Nieman
    3 years ago

    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!!


  3. peggy vurgason
    3 months ago

    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,


    • Karen
      2 months ago

      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


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