Who’s afraid of starch? It’s all in the cooking!
Starch gets a lot of negative publicity these days and, whilst some may be deserved, it is often the way it is used which is at fault.
Horses are designed to function on fibre and, in their natural environment where their basic aim is survival, it’s sufficient to keep them going. But having domesticated them and imposed on them the rigours of training and competition, we now find that fibre is not generally enough to provide the fuel they need to perform.
We’d also find it hard to deal with the dramatic fluctuations in condition that feral horses and ponies go through in the wild, so alternative energy sources, such as cereals, have traditionally been the answer. That said, there are still plenty of horses and ponies, particularly those of native type, whose systems have adapted to deal with a sparse diet and as such now do almost too well on modern pasture.
Starch is made up of chains of glucose molecules and is tightly packed in granules into cereal grains. It is there to provide food for the growing seedling, should the grain (seed) germinate and grow into a new plant, rather than being fed to our horse! It provides a much more concentrated source of energy than fibre so the horse only has to eat a relatively small amount to gain the energy he needs.
Much of its bad reputation has been gained though, through feeding excess quantities of grain. This leads either to over excitability, as the horse receives too much energy, or to digestive or metabolic disorders, such as stomach ulcers, colic or tying up, as the horse’s digestive system struggles to cope with the starch levels.
The important thing with starch is that it must be digested in the stomach and small intestine and should not be allowed to pass on to the hind gut. The horse has a relatively small and “unstretchy” stomach which limits the size of the meals we can give – too large and some undigested starch could flow out and reach the hind gut. So what’s the problem there?
Remember the finely balanced population of microbes who reside in the hind gut and, amongst other things, digest the fibre portion of the horse’s diet? These bacteria are sensitive to any change in their environment and do not survive exposure to starch. So, if undigested starch reaches areas of the horse’s gut that it shouldn’t, not only will it disrupt the bacterial populations, so reducing the efficiency of fibre digestion, but toxins produced by the bacteria as they die can lead to diseases, such as laminitis.
Humans find starch easier to digest if it has been cooked – we don’t eat raw potatoes and always cook pasta and rice before we eat them! As research into equine nutrition and feed technology has progressed, we’ve found that cooking vastly improves the digestibility of starch for horses too, helping more starch to be absorbed in the small intestine.
The most efficient cooking method has been shown to be micronisation using infra red energy and which is the technique chosen by Baileys. Firstly the grain is soaked to increase the moisture content and swell the starch granules. The grain is then passed under the infra-red heat source and, as water vapour pressure in the grains rises, starch granules swell and fracture – a process known as “gelatinisation”. The grain is then rolled to stop the gelatinised starch from binding to the protein in the grain, which would render it indigestible.
To achieve maximum gelatinisation of the starch, and thus maximum digestibility, the temperature and length of time for which the grain is exposed to the heat are crucial. Baileys are meticulous in achieving this balance, with every tonne of grain that passes through, so are confident about the digestibility of the starch content of all their products.