| Since its first domestication (about 5000bc), the horse | | | | feed to slow the horse down as it eats or by |
| has been used for many purposes; initially for meat, | | | | frequently feeding smaller meals. It is also important to |
| then for transport and for use in battle, leading us to its | | | | remember this when wanting to exercise after |
| modern use, for pleasure. The horse is suited to a high | | | | feeding. Greedy or fast eating horses will already be in |
| fiber diet due to the continual microbial fermentation | | | | a state of relative dehydration. There are other |
| within its caecum and colon. It is its domestication that | | | | factors that need to be considered in relation to |
| leads the horse to use and therefore need more | | | | exercising after feeding:o Glucose reaches its peak |
| energy than can be provided by their usual high fiber | | | | between 1-3 hours after feeding. The brain can only |
| natural diet of grass. It is these requirements that have | | | | use glucose as a fuel and if the horse is exercising at |
| lead to the inclusion of grains and supplements to the | | | | this time would result in a larger drop in glucose levels. |
| horse's diet. In many ways, this being possible has lead | | | | The horse would have to rely even more on stored |
| to a lot of benefits, but it also has the potential to result | | | | glycogen potentially resulting in a quicker onset of |
| in many problems. | | | | fatigue.o Having a full GIT after eating would restrict |
| Feeding horses is a combination of science and art. By | | | | the amount of space available for lung expansion.o |
| using information relating to the scientific processes of | | | | Blood flow is diverted to the gut to enable digestion |
| digestion, metabolism and nutritional requirements, the | | | | effectively. This would reduce the blood flow to |
| owner can put this factual knowledge into practice for | | | | muscles used when in work, again quickly bringing on |
| each individual horse. | | | | fatigue. |
| The first part of the horse's digestive system is | | | | Food travels quickly through this upper section of the |
| relatively simple; it is the later part that requires us to | | | | GIT and most of it will reach the Caecum / Colon |
| carefully consider how we feed our horses. Horses do | | | | within 45 minutes. This does vary depending on the |
| not ruminate like cattle and therefore need to take in | | | | feed fed and the way in which it is fed. Fiberous food |
| small amounts of food, chew and swallow; this is | | | | moves the slowest though the horses GIT. It is in the |
| where the term 'trickle feeders' stems from. The | | | | Caecum and colon that the majority of the nutritional |
| nature of the feed that the horse eats will greatly | | | | value of the feed is utilised and the time it spends in |
| influence the chewing rate and speed of ingestion. The | | | | here determines the effectiveness of the processes. |
| average 500kg horse will chew at a rate of 40 | | | | Digestion and absorption of carbohydrates relies on |
| minutes per kilogram of hay. | | | | microbial action and absorption in this section of the |
| The same 500kg horse would eat oats at a rate of 10 | | | | GIT, there is very little enzyme activity here. The fact |
| minutes for each kilogram! This can have knock on | | | | that the microbial fermentation occurs after the |
| effects. The less time eating, the more chance | | | | 'monogastric' first part of the horses GIT is very |
| behavioural problems can occur out of boredom. The | | | | important to the way we feed our horses. |
| ability to eat food so quickly also prevents the horse | | | | It is this microbrial breakdown that can rid the large |
| from chewing and breaking down the particle size of | | | | intestine of undigested proteins and urea, resulting in |
| food before swallowing, significantly reducing the | | | | urea as a byproduct, the majority of which is reutilised |
| nutritional value that is gained from the feed ingested. | | | | by the bacteria, actually stimulating important bacterial |
| Saliva is produced in response to chewing, rather than | | | | growth. Any microbial protein synthesised here can not |
| in anticipation of food. The more food is chewed the | | | | be used by the horse. Horses requiring higher protein |
| more saliva the horse produces. It has been suggested | | | | levels need to have dietary protein supplements which |
| that 12 liters of saliva is produced a day on a hay and | | | | can be broken down before the large intestine. Most |
| concentrate diet. On a diet of dry hay up to 100 litres | | | | of the water soluble vitamins are synthesised in the |
| can be produced. This helps to lubricate the bolus and | | | | large intestine, so no additional feeding of these are |
| prevent choke. | | | | needed. It is in the large intestine that water is stored |
| The horse's stomach volume is between 9-15 litres. It is | | | | and absorbed. |
| relatively inelastic and ingested food is retained for 20 | | | | The upper part of the digestive tract has a small |
| minutes although there is always some food retained | | | | capacity and the horse has digestive and metabolic |
| for several hours following a meal. The larger the meal | | | | limitations to high grain, highly soluble carbohydrate diets. |
| the quicker the horse's stomach empties. This also | | | | Due to the requirements we place on our horses to |
| means that food empties into the small intestine more | | | | exercise for prolonged, frequent or intensive periods of |
| quickly. The dryer the bolus that passes though the | | | | exercise, it it vital that we remember that they have |
| horses digestive system, the slower the digestion and | | | | not evolved to cope with large quantities of grain feed. |
| mixing of the feed with the gastric juices, reducing the | | | | Whilst giving the horse the energy to perform as we |
| effective fermenting that needs to take place. | | | | require, the horses stomach can easily be |
| Most digestion occurs in the small and large intestines, | | | | overwhelmed and its digestive capability can be |
| rather than the stomach. Naturally the horse will graze | | | | reduced. |
| for 16-20 hours a day and they have evolved without | | | | This can lead to rapid fermentation of the grain |
| a gall bladder. Bile is secreted continuously as food | | | | carbohydrate in the hindgut, causing a decrease in the |
| passes through the gastrointestinal tract. It is this that | | | | pH. This in turn will cause a negative chain reaction |
| helps alkalise the digesta and is required to emulsify | | | | including a change in the microflora within the GIT, |
| and digest lipids. A horse's dietary energy is provided | | | | changing the action of these, possibly allowing the |
| to the horse by 4 sources:o Starcho Cellulose (found in | | | | release of endotoxins that can cause damage to the |
| a primarily fiberous diet)o Fats (usually less than 3% of | | | | large intestine. It is good to remember that a horse on |
| total feed intake and any supplementary oils should be | | | | a roughage based diet would not result in decreases in |
| introduced gradually)o Proteins (not a preferred energy | | | | the GIT pH and therefore none of the potential |
| source due to their inefficiency for this purpose) | | | | problems associated. This is one of the reasons that |
| Adult horses secrete over 100 litres of fluid per day | | | | supplementary oils and fats have become popular as |
| into this pre-caecal part of the gastrointestinal tract | | | | a non-starch energy source. |
| (GIT). Large pelleted or grain filled meals fed | | | | Good nutrition can not improve the core ability of a |
| infrequently can result in a low blood volume due to to | | | | horse but poor nutrition can place limitations on its |
| meal stimulated secretions in the upper GIT. These | | | | performance. |
| changes can be avoided when chaff is included in the | | | | |