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How grain processing impacts equine digestive health

How grain processing impacts on equine digestive health

How grain processing impacts equine digestive health

Grain is often fed to horses as an additional source of digestible energy. This includes performance breeding and growing horses that require elevated energy requirements above what forage alone can provide.¹

Grain provides energy in the form of starch (long chains of glucose molecules). However, when fed raw, the physical form of the grain prevents contact with the enzyme amylase and digestion of the starch within the small intestine.¹

The undigested starch travels to the hindgut where it is rapidly fermented by the hindgut microbiome. Fermentation of starch in the hindgut disrupts the delicate balance of the microbial population by reducing the population of beneficial fibre-fermenting bacteria and favouring undesirable starch-fermenting bacteria.²,³ As a result, it can lead to a build-up of lactic acid and hindgut acidosis. Outward signs of this in horses include soft and unformed manure, poor hoof quality, behavioural issues, reduced appetite, colic, and laminitis.²

Processed or cooked grains help alleviate these issues. The level of processing of the grain influences the level of digestion within the small intestine. Mechanical processing, such as grinding and cracking, only breaks down the outer layers of the seed coat and cell walls. It is not as effective at increasing starch digestion compared to processing methods that use heat and water which further breaks down the grain structure.¹


The cooking process of extrusion is one of the most effective cooking methods, with an in vitro study showing increased starch digestion of extruded corn, compared to micronised and raw corn.4 

During the cooking process of extrusion, the milling and grinding of grain break the outer seed coat and cell walls of the grain and pre-conditioning and steam extrusion soften and cook the grain. This breakdown of the outer layers of grain, combined with the changes in the structure of starch granules, allows for the enzymatic digestion of starch to occur within the small intestine.4

The digestion of starch within the small intestine reduces the amount of starch that reaches the hindgut, allowing for the maintenance of a healthy microbiome and the efficient fermentation of fibre.4

Pryde’s EasiFeed utilises this processing method to ensure a highly digestible and quality product, that supports the health of the hindgut microbiome.

Visit your local PGG Wrightson store to discuss which product from the EasiFeed range is best for your horse.


1 Hoffman, R.M. (2013). Carbohydrates. Equine Applied and Clinical Nutrition, pp.156–167. doi: b978-0-7020-3422-0.00008-0.

2 Julliand, V., & Grimm, P. (2017). The Impact of Diet on the Hindgut Microbiome. Journal of Equine Veterinary Science, [online] 52, pp.23–28. doi:

3 Merritt, A.M., & Julliand, V. (2013). Gastrointestinal physiology. Equine Applied and Clinical Nutrition, pp.3–32. doi:

4 Richards, N., Rowe, J., & Hinch, G. (2004). Enhancing Starch Digestion in the Equine Small Intestine. [online] Available at: