In Defense of Starch

Like a celebrity on a downward spiral, starch has been getting a lot of press in the last few years…and most of it negative.  Unlike celebrities, starch doesn’t gain anything from the media exposure.  Although it may be unpopular, I’d like to take a moment to say a few words in defense of starch; a (recently) under appreciated, yet useful nutrient in horse diets.

But first, let’s start with what it is.  Starch is a complex chain of sugar molecules, which is the main source of energy for plants.  It is stored within the cell walls of the plant and therefore, considered a nonstructural carbohydrate (NSC).  Starch in horse feeds are most commonly sourced through grains such as oats, barley, corn, rice or wheat and the co-products of these grains such as corn distillers grains, rice bran or wheat midds. 

Glycemic response of oats and controlled starch diets, in horses

When ingested, starch molecules are broken down into smaller sugar molecules (glucose) that are readily absorbed. With the help of insulin, the glucose in the bloodstream is ‘picked up’ by muscles and other tissues to either be used to support activity or stored (as glycogen) for future energy needs.  Hard working and active horses need glucose and glycogen to support their activity levels and recovery from activity.   It’s also worth pointing out that NSC’s are a very efficient pathway to providing energy to the horse and to aid in muscle recovery (glycogen repletion), particularly in horses performing athletic activities.

Most horse owners know that too much starch at one time can overwhelm the horse’s digestive system.  That excess, undigested starch could leak into the hind gut where it can rapidly ferment, leading to an overproduction of gas and lactic acid, which in turn, could cause gas colic and/or acidosis which could then lead to laminitis or other issues.

You’re probably wondering, if it’s needed by horses for energy, but also potentially dangerous then how does the horse get what he needs without wreaking havoc?  The answer lies in the QUANTITY of starch consumed in each meal.

The majority* horses can tolerate a moderate level of starch each day.   This is not to say, all at one time.  There is a big difference!  Consider the digestive system of a horse to be like a waterway – it can tolerate a certain quantity of water running through it (or in this example starch) but if there is too much at one time, the water overflows and goes where it is not supposed to go.  Same with starch in the digestive system – the body can handle a moderate quantity of starch released at a controlled rate, but too much at one time (or from too big of a meal) and the whole system gets out of whack. 

I offer up one last nugget to consider: oats – the long-time staple of ‘safe’ feedstuffs for horses, actually contains approximately 40% starch. Now there’s something to think about…

So, in defense of starch, I’d just like plead the following.  When consumed in moderate amounts/meals,  frequently over time, starch is a useful and practical source of energy for most horses. 

In my next post, we’ll talk about how to evaluate starch levels in feeds.  Stay tuned for more….

*Horses diagnosed with a form of Equine Metabolic Disease (EMS) require a diet that is closely managed to control and limit the amount of NSC (including fructan from forage) in their diet. 

6 Replies to “In Defense of Starch”

  1. Hi there, I have a question about the Empower balance formula you have. I have just started my welshx 13.2h pony on it and I am unsure if this is the correct feed for his condition. He is extremely overweight and after having him vetted we found that he has partially rotated on one foot. Will this product with correct feeding amounts help strip him of the excess weight?? He weighs about 750 to 800lbs. I am feeding him a cup am/pm…thank you for your time-

    1. Hi Claire,

      Sounds like you’re on the right track with your pony. Empower Balance is the best choice for him at this point, and I’m glad you’ve got an estimation of his weight already. It’s also important to use a weight tape and the body condition score system to help monitor his progress with weight loss.

      One thing I’d encourage you to do is get a scale and weigh his feed AND his hay. This way you can closely monitor how much he is getting for his total diet. Hay should be fed at a rate of 1% – 1.75% of his body weight per day, and depending on the quality of hay, would encourage you to stay on the lower side of that range. Which means he would get between 7.5 – 13 pounds of hay each day. You didn’t mention the type of hay he is getting, but grass generally is lower in digestible energy (DE) than alfalfa, though it can be higher in non-structural carbohydrates (NSC). For a pony who is already overweight and has shown some rotation in at least one foot, managing his intake of NSC in his entire diet is important for his current condition. Soaking his hay for at least 15 minutes will remove many of the NSC’s in his hay. Remember to discard the water.

      His Empower Balance should be fed at a rate of 0.75-1.5 pounds per day. Since it is so concentrated in nutrients, it can be fed at low amounts. Please keep in mind to adjust his rate as he loses weight to insure he is getting the balanced nutrients he needs.

      A horse or pony with founder/laminitis can lead a relatively normal life with a few extra management steps. Also remember to slowly manage transition to spring pasture and if possible, use a grazing muzzle to keep him from over indulging on pasture. You can find more useful tips on our laminitis page here:

      Best wishes for him and please let us know if you have more questions!
      Megan C.

  2. We have been told that our 5 yr old quarter horse mare that we run barrels on could be tying up due to to much starch. She seems to only tye up on muggy/ humid days.

    1. Hi Sissy,

      Thank you for your question. Can you tell me a little more about your mare and what she is being fed? What kind of feed is she on and approximately how much (in pounds) does she get each day? What kind of hay does she eat and can you tell me if she is turned out daily or does she live in a stall? Are you providing any supplements or treats to her?

      There are a number of causes of tying up and if you have not already, I strongly recommend you check with your veterinarian for a diagnosis. It is possible that she may have an equine metabolic disorder, but identifying the exact one is important for treatment and management.

      Generally speaking, horses with a form of EMS should be managed with frequent turnout, fed a good quality grass hay with feed that provides energy mainly sourced from fat/fiber, with a controlled starch and sugar design. Many of the forms of EMS in horses respond well to supplemental vitamin E, but again, check with your vet to confirm.

      Finally, free access to salt and fresh, clean water are important.

      Hope this helps and please let us know of more questions.
      Megan C.

  3. How many grams of starch per day is considered “moderate?” I can’t find anywhere the RDA of starch for a horse. Or sugar. I have calculated how much starch and sugar my horse is getting per day, but I have no idea if that is too much or too little. Thanks for your help.

    1. Hi Christine,
      Great question. The current NRC Nutrient Requirements for Horses does not provide an RDA of starch for a horse. Based on research, we know that what is important is controlling starch intake per meal to reduce risk of starch overload in the hindgut. Research suggests limiting starch intake to less than 2g starch per kg bodyweight per meal. So, if for example you are feeding your 1100# (500 kg) horse a total of 8# of an 18% starch feed per day split into two feedings, that would mean you are feeding 4# per meal. 4# feed * .18 = .72# starch *454 = 326 grams of starch in the meal. 326 grams / 500 kg bodyweight = .65 grams of starch per kg bodyweight which is well below the 2g threshold suggested.

      If your horse is at risk for gastric ulcers, it is recommended to stay <1 g starch per kg bodyweight per meal. If your horse has a metabolic disorder such as insulin resistance it is recommended to stay <.3 g starch per kg bodyweight per meal. Best of luck! Abby K.

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