08/07/2025
Feeding Starch to Horses – What’s the Deal?
Starch – a suitable energy source for horses, or not?
Choosing the right type of concentrate feed is crucial, but what exactly is the right feed? The answer isn't simple and depends heavily on the horse itself and the level of effort or performance expected. In this decision-making process, the amount of starch often plays a key role. But do horses actually need extra starch – and if so, how much? It’s a complex question without a one-size-fits-all answer. That’s why it’s important to first understand the topic more deeply.
What is Starch?
Starch is a carbohydrate that gets broken down in the horse’s small intestine by the enzyme amylase into glucose molecules. These glucose molecules enter the bloodstream and provide immediate energy for the horse. Starch is an efficient energy source and also plays a role in muscle recovery.
What Does the Horse Need?
While you can’t change a horse’s temperament with concentrate feed, you can support its performance effectively. If your horse lacks energy by nature, starch can provide a helpful energy boost. For high-level (sport) performance, horses need accessible energy to meet demands. Always consider the horse’s specific needs and prioritize quality feed.
Grains are naturally high in starch. Processing methods such as crushing or heat-treating (e.g. steaming, puffing) increase starch digestibility and absorption. Avoid feeding large amounts of starch in one meal—spread concentrate feed across multiple smaller meals for better digestion.
Supporting Recovery
Starch is particularly useful for short bursts of intense activity. Although research in horses is still limited, initial studies suggest that horses recover faster post-exercise when starch is provided after training. Compared to humans, horses take longer to replenish glycogen stores in their muscles.
Feeding starch before a workout appears less effective. However, scientific research (Valberg et al., 2023) has shown that starch-rich diets result in higher muscle glycogen levels compared to starch-poor, fat-rich diets. This indicates that post-exercise feeding with well-processed (gelatinized) starch sources may aid muscle recovery.
Example digestibility of maize (corn):
Raw maize: 29% digestible
Crushed maize: 47% digestible
Heat-treated maize: 90% digestible
Don't Overdo It
Despite its benefits, starch must be fed in moderation. A horse’s capacity to digest starch is limited. If this threshold is exceeded, undigested starch may reach the hindgut, disturbing the gut microbiome. This can lead to health issues such as diarrhea or colic.
It's important to note that negative effects typically only occur with high-starch diets (40–50%) (Willing et al., 2009; Linden et al., 2009; Kronfeld et al., 2005). So don’t jump to conclusions too quickly.
Sugar-Sensitive Horses
Some horses are sensitive to sugars—for example, those with insulin resistance. Because starch breaks down into sugar, it’s essential to keep starch levels low in these horses' diets.
Advice for horses sensitive to starch (e.g. insulin-resistant horses):
Feed a maximum of 1 gram of starch per kg body weight per meal
Offer multiple small meals throughout the day
Always pay attention to forage quality—the foundation of every diet. Forage with over 15% sugar content is unfortunately becoming increasingly common.
Oil as an Energy Source
Starch can partially be replaced by other energy sources such as oil. Oil provides more energy per gram than starch, but it is released more slowly. Also, the amount of oil a horse can safely consume is limited, and it’s worth noting that horses are not natural fat-eaters.
Conclusion
Starch often has a bad reputation, but it can absolutely contribute positively to the performance of sport horses. However, each horse is different, so it’s crucial to tailor feed to the individual’s needs. Starch is an efficient energy source—but one that must be used wisely due to the horse’s limited digestive capacity. This maximum capacity is, however, higher than is often stated. Don't believe everything you hear—when in doubt, always consult a qualified equine nutritionist.
Appendix 1:
HAVENS Horse Feeds – How Much Can You Feed?
Rule for Insulin-Resistant Horses: Max. 1 g starch per kg body weight per meal
Extra safety guideline: Max. 2 g starch per kg body weight per day
Example for a 600 kg horse:
Feed Type Per Meal Per Day
Gastro+ 3.14 kg 6.28 kg
Draversbrok 1.70 kg 3.40 kg
Natural Balance 1.55 kg 3.10 kg
Senior Crumbs 4.40 kg 8.80 kg
Rule for Leisure Horses:
Max. 1.5 g starch per kg body weight per meal
600 kg horse:
Feed Type Per Meal
Gastro+ 4.17 kg
Draversbrok 2.55 kg
Natural Balance 2.33 kg
Senior Crumbs 6.60 kg
Rule for Sport Horses:
2.0 to 2.5 g starch per kg body weight per meal
600 kg horse:
Feed Type Per Meal
Gastro+ 6.28 – 7.85 kg
Draversbrok 3.40 – 4.25 kg
Natural Balance 3.10 – 3.88 kg
Senior Crumbs 8.80 – 11.0 kg
NOTE: These amounts are guidelines only. (for Insulin-Resistant Horses)
We never recommend feeding more than 2 kg of concentrate per meal or more than 3 kg per day!
⚠️ Also keep in mind: Feed composition matters.
Example: Natural Balance contains a high proportion of spelt (35%), which has a relatively low glycaemic index (GI). This results in smaller fluctuations in blood sugar levels.
