Nutritional Articles

Crude cell material supplies energy for the long term.

Published: 2013-02-11

Only twenty hours after a substantial dose of hay the meal has been completely transformed into fuel. Crude cell material is also the indisputable pacemaker of the intestines.

A horse gobbles up its food, but its intestines are not up to this. In its evolution the horse changed from a leaf eating forest inhabitant to a grass eating steppe animal. Its digestive system has adapted to the eating of small portions of mostly difficult to digest grass. It already starts in the relatively small stomach, where the food arrives at first. Next is a proportionally ‘normal' small intestine. The latter one takes care of the digestion of the materials that are most easy to digest. After the small intestine the more voluminous large intestine starts, in which bacteria digest and transform crude cell material from the roughage into important substances the horse's body needs, such as volatile fatty acids for energy.
Starch and sugars rapidly supply, jerky and brief, energy the horse can draw on. Opposed to this, the energy from crude cell material becomes only gradually available. With hay this starts for example four to five hours after the meal. So long as the crude cell material is still being digested in the large intestine, the energy continues to become available. When a horse eats a portion of hay of ten kilos the digestion and processing will take about twenty hours, which means almost round the clock. If we give this ration all in one time we will fully burden the digestive tract and the efficiency of the transformation in nutritive materials will decrease. If the horse is given smaller portion several time a day, the burden will be less and the efficiency higher.


Volatile fatty acids
Millions of bacteria in the large intestine of the horse make sure that the crude cell material is transformed into volatile fatty acids such as acetic acid, butyric acid and proprionic acid. These volatile fatty acids in the bloodstream serve as an energy source for organs, muscles and nerves. Especially for horses that need a lot of endurance such as in endurance competitions, military, trekking and marathon, the slowly decomposing energy of the volatile fatty acids will be a welcome supplement in the total energy management. Fatty acids also have a favorable influence on the quality of the intestinal flora (all living micro organisms in the intestine that take care of the digestion and the transformation of the food). Moreover, the volatile fatty acids influence the water resorption and combat diarrhoea. Furthermore they prevent the formation of the detrimental Salmonella and Clostridia bacteria and they provide for a better hygiene in the digestive tract. From the nitrogen in the food rests the bacteria form proteins of high biological value and water soluble B-vitamins. These vitamins are important in the metabolism. All in all, volatile fatty acids are indeed very useful.

Transit speed
Dormant intestines have to be woken up and keep it going for an optimal digestion. The propulsion of the mass of food being digest and the speed with which it is done is called the transit speed. If the transit speed is not geared to the digestion, the ‘factory' will not run well. The digestion of concentrate (proteins, carbohydrates and fats) mainly takes place in the small intestine.
Crude cell material present in roughage is barely broken down in the stomach and the small intestine. It is immediately sent to the large intestine where it is being digested bit by bit. The crude cell material starts off the locomotion of the total digestion. Crude cell material is indispensable for the transit speed. If the large intestine has nothing to do, there is a chance that the passage stimulant lacks and that digestion will stop whilst there is still food in the intestine. This food will then start to rot. Colic, muscle and hoof constriction can be the result. Dat voedsel gaat rotten. This means that roughage keeps the ‘factory' going and consequently prevents all of these problems. It is a good ‘filling' of the blind gut and large intestine as well. The latter two are rather flexible with horses and when not sufficiently filled the chance on colic (intestine twisted or entangled) with a bad outcome exists.

Variable quality
Actually, we should always have the roughage, i.e. the hay, analyzed. The quality of roughage may vary widely. The digestibility of the cellulose present can differ, but also, next to other quality criteria such as protein level and nutritive value, the percentage of crude cell material per kilo of roughage may vary. For horses, in contrast to cows, the crude protein level should not be too high and the amount of crude cell material play a far more important role (see table). Another substance, lignin, determines the decomposability of the roughage; feed with a lot of lignin is badly digestible, like straw for example.
In the large intestine the bacteria are accustomed to a certain digestibility and amount of crude cell material that has to be processed. If the composition changes suddenly, the micro organisms will have to adapt first to the new situation. Besides, this is also valid for humans. Those suddenly switching over from standard European food to Asian food will almost always be confronted with intestinal troubles. Until the moment that the micro organisms in the large intestine have adapted, the chance exists that the activities in the intestines are upset. Again the known nasty results will be inflammations, diarrhoea, lactic acid, hoof constriction and colic.

Correct quantity

In any case, crude cell material is an important part in daily nutrition. It is advisable to be aware of the quality of the roughage and when changing over to another quality to do this gradually. Of course, this goes for roughage too. A good supplier is able to present an analysis of the crude protein and crude cell material level, the VEP-value and the calcium and phosphor level. For that matter hay, straw and alfalfa are not the only sources of crude cell material: grass and foliage (both to a certain degree), oats pellets, flax chaff, soy pods and beet pulp also contain crude cell material. With all of these ingredients in the right proportions the battery of the horse will never be flat. Almost round the clock the horse has fuel at its disposition on which it can draw immediately, energy that is becoming constantly available.

Obligatory nibbling

The horse eats up its concentrate in a quarter of an hour and then has nothing left to nibble on. This is gnawing (figuratively): the animal bores himself to death. For horses it is completely natural to continually nibble and psychically they are really geared to this. A horse that has nothing to do will resign itself to this and become apathetic to a certain extent or will invent some ‘stable naughtiness'. By giving sufficient roughage spread throughout the day, the horse has something to do and the digestion keeps going on in a natural way. For instance, because of lack of roughage in their ration stomach ulcers are very common in sports horses. Another advantage of spreading the feeds is the improvement of the quality of digestion: more output from the same bale of hay. A horse may eat roughage that is not rich in protein without restriction when it turns out normal labour. For horses doing nothing the ‘figure' plays an important role. They should be given roughage as regular as the others, but portions should be smaller.

Quality of the hay

Coarse stemmed hay with a low crude protein level and a high percentage of crude cell material is most fit for horses. The calcium-phosphor ratio (percentage of calcium divided by the percentage of phosphor) should not be higher than 3 or lower than 1. And even better: not higher than 2 and not lower than 1,4 (source CVB august 1995).

% crude cell material % crude protein VEP-value Ratio g/kg Ca/P Quality
With 100% dry matter 30 12 674 6,2 Ca/2,7 P Low protein
28 14,5 700 8,5 Ca/3,4 P Average protein
26 16,5 740 5,1 Ca/3,9 P High protein
With 83% dry matter and 17% liquid 23 10 560 Moderate protein
23 12 581 Average protein
21 13,7 614 High protein