Starch In Your Horse's Diet
- 10 minutes ago
- 3 min read
Most owners of horses with metabolic dysfunction know that they should avoid feeds that are high in sugar (which we covered in this post), but you also should consider limiting starch.
Starch is a problem because:
Insulin Resistance
These horses have impaired insulin sensitivity, meaning their bodies don’t respond properly to insulin.
When starch is digested into glucose, it triggers excessive or prolonged insulin release, which can lead to:
Laminitis
Fat deposition in abnormal areas
Inflammation and oxidative stress
2. Delayed Glucose Clearance
In healthy horses, blood glucose spikes after a meal and then returns to normal. In metabolic horses, glucose stays elevated longer, increasing the risk of tissue damage and hoof breakdown.
3. Hindgut Fermentation Risk
If too much starch is fed at once it may bypass the small intestine and ferment in the hindgut. This can cause:
Hindgut acidosis
Microbial imbalance (die-off of gut flora)
Colic or laminitis
It's not just owners of horses or ponies with a history of metabolic dysfunction that should consider limiting starch.
High grain feeds in large volumes are routinely fed to racehorses.
Research shows that high starch diets result in higher reactivity and higher heart rates than horses fed a high fibre diet.
Research also shows that there is little difference in performance between high starch and high fibre diets for racehorses.
Recommended limits for starch:
≤0.3–0.5 g/kg body weight per meal
≤1 g/kg body weight per day
<10–12% non structural carbohydrate in total diet for horses with metabolic dysfunction
(this means starch and sugar combined)
Highest starch grains:
Corn (Maize) 65–75% Highest starch of all grains; must be processed (e.g. extruded, micronized) for safe digestion
Wheat 60–65% Very high starch; rarely fed whole to horses due to digestive risks.
Barley 55–60% High starch; less digestible raw—often flaked, steam-rolled, or micronised.
Common feeds that contain corn, and barley/wheat:
Pryde's
Energy Pak
Bio Mare Cubes
Easi Sport
Easi Condition
Furney's
Racehorse Komplete
Studbreeder Komplete
Koola Komplete
Mitavite
Extrucorn
Extruwheat
Extrubarley
Munga
Sustaina
XtraCool
Barastoc
Race'N'Win
Command
Hygain
Release
Tracktorque
Riverina
Horse and pony pellets
Castlereagh
Econocool
Condition More
Please note: this is not an exhaustive list. Please read your feed bag label carefully. If it says "cereals" that can mean corn, barley and wheat.
Solutions?
If your horse has metabolic dysfunction, or a history of gut issues, consider limiting starch as well as sugar.
It is very difficult to know what is in a pellet. When they say 'cereals', ingredients may change based on what they can get for the best price, which will vary.
If you buy single ingredient feeds - not necessarily in a shiny bag, you have much more information about what the contents are. You can research the sugar/starch content to make sure the combined sugar/starch is below 10%.
Low starch / low sugar high fibre options are beet pulp and soy hulls. Both of which need to be soaked well before feeding, which make them a good carrier for supplements, a source of hydration, and a mash that assists horses with compromised dentition.
Legumes - lucerne in particular, are generally low sugar, low starch and high in protein.
Read more about starch here:
Starch Digestion in the Horse
The effects of a high-starch or high-fibre diet on equine reactivity and handling behaviour
Effect of high-starch or high-fibre diets on the energy metabolism and physical performance of horses during an 8-week training period
Support your horse's gut health with our prebiotic probiotic bundle:
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