How does processing horse feed help digestibility?

Some grains such as oats can be fed whole, others such as maize are likely to result in digestive problems if fed in their raw form. However, by processing grains, their digestibility and therefore nutritional value is enhanced.

Feed processing is where the raw materials used to make horse feeds such as oats, barley, maize and soya bean are processed by mechanical (rolling, grinding), thermal (roasting, micronizing) or thermo-mechanical (steam – flaking, extruding, pelleting) techniques.

Grains are an important source of energy for most horses. This energy is mainly derived from the starch found in the centre of the grain. However, just like us, horses find it hard to digest unprocessed starch, which is why we always cook rice and pasta before we eat them! As research and innovation into cooking techniques and equine nutrition has progressed, it has been found that cooking vastly improves the digestibility of feed for horses too. Processing horse feed helps to maximises the digestibility of nutrients in the small intestine and minimise the risk of digestive disorders.

Starch must be digested by enzymes in the horse’s small intestine so that they can utilise the energy it contains. However, extracting this energy is not easy for the horse because it is “packaged” within the cereal grain. Physical process like rolling, flaking or grinding disrupts the structure of the cereal grain, breaking down the seed hull and aleurone layer, thereby exposing the starch. Although, mechanical processing does slightly improve starch digestibility, it only causes minor disruption to the cell walls of the inside of the grain and leaves a majority of the protein matrix and starch granule structure intact.

To further improve starch digestibility the cereal must be ‘cooked’. Cooking involves the use of a combination of heat, moisture and/ or pressure to break down the tightly packed bonds in the starch granule, a process is known as gelatinisation. This processing and cooking techniques helps to break down the barriers the enzymes in the horse’s small intestine have to face in reaching and digesting cereal grain starch, meaning the starch becomes more available and easier to digest for the horse.


Figure 1 Grain anatomy

Starch from most grains that are fed whole, or are simply cracked, bruised or rolled but not cooked, will remain largely undigested as it passes through the small intestine. Starch that is not digested in the small intestine will enter the hindgut and this can cause severe, even life-threating, problems.

Undigested starch in the horse’s hindgut is rapidly ferment by microbes. This results in excessive production of acids, which lower the hindgut pH (creating an acidic environment). This drop in the hindgut pH can cause significant problems including colic, endotoxaemia, systemic acidosis, laminitis, reduced fibre fermentation, poor appetite as well as deficiencies in B-vitamins and vitamin K. Research into equine nutrition has helped us to avoid problems with undigested starch and we apply that research in processing ingredients to make feeds at Connolly’s Red Mills.

Our RED MILLS feeds are made using a five stage process. Our team of expert RED MILLS Agronomists work closely with local grain producers and trusted global ingredient suppliers to source consistent, quality raw ingredients. All our raw ingredients are then rigorously tested at our on-site laboratory to ensure that they meet our strict quality standards. Only then do the raw materials enter our production mill to be make into horse feed.

At Connolly’s RED MILLS we developed some of the most technologically advanced manufacturing processes in the world, these include:

Steam cooking

To achieve maximum starch gelatinisation and thus maximum digestibility we steam cook our cereals before they are cooled, flaked and dried. Steam cooking, is a hydrothermal process where the cereal gains are exposed to steam for 1 hour at 100oC. Exposing the cereal grain to water and heat causes the starch granules swell and fracture, a process is known as gelatinisation. The temperature, moisture levels and length of time for which the grain is exposed to the heat are crucial. The Red Mills Research and Development team have completed various studies to ensure that we get this balance absolutely perfect.

Double Pelleting

All our cubes and pellets are made using a blend of quality whole grains and are pelleted twice to ensure maximum digestibility and cube/pellet quality. The pelleting process starts with grinding of all the ingredients. The ground ingredients are then pushed under high pressure through a pellet die. The pellets are then reground and once again passed through another pellet die producing a pellet or cube of the desired size. The combination or grinding, heat and pressure used in the double pelleting process creates a highly digestible, nutritious and dust-free feed.


Connolly’s RED MILLS use soya beans for their complimentary amino acid profile and oils. The soya beans are ground and then passed through the extruder, a steel tube with a rotating auger or screw.

The extruder cooks the soya beans using a combination of pressure and hot steam. Extrusion improve the quality and digestibility of the soya by removing trypsin inhibitor, an anti-nutritional factor naturally found in soya beans.

You can find out more about our feed making process, called Precision Nutrition, here.

The health of your horse is hugely influenced by its diet. It is vital that the feed offered is of the highest quality in order to support optimum health and performance. Our understanding of feed processing and manufacturing together with our huge and ongoing investment in feed technology means that you can be sure that Connolly’s Red Mills horse feeds are the very best for your horse.

If you’ve got any nutrition queries or would like to know more, For further information and advice please Get in Touch with our Experts Team.

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