Feed News Quarterly
Understanding The Basics
Feeding your horse: Choosing the right feed
Micronizing: Improved feed efficiency
Why is fibre so important to horses
Vitamins and Minerals in horses
What is digestible energy in horse feed
Discipline related
Common Equine Ailments
Laminitis - Feeding the Laminitic Horse
Feeding your horse after colic
Ulcers in horses:Why and what to do?
Joint structures and problems arising from their failure
Breeding
Management Issues
Pasture management for horses with metabolic disorders
Energy requirements of a racehorse
Bringing horses back to work after a spell
Feeding horses during a drought
Feed Supplementation
Why is fibre so important to horses?
You will often hear nutritionist say that fibre must be the base of all diets. The reason for this is that horses evolved on a high fibre diet comprising of medium to low quality pastures. As a result its digestive tract has evolved to cater for this type of diet. Horses have an enlarged caecum and large intestine (large and small colon), which act as a large fermentation vat in which microorganisms break down feeds via the process of fermentation. This process is relatively delicate as the bacteria population in the hindgut of the horse are designed to process fibrous sources of energy. If a high starch diet is suddenly introduced such as a high grain diet, the bacteria composition will change and an excess of heat, gas and acid will be produced. This will lead to the bacteria dying off and the release of endo toxins, which can increase the risk of laminitis, colic and acidosis.
Fibre is the material of the plant cell wall that gives plants its rigidness. There are many types of fibre including lignin, cellulose, hemi-cellulose and pectin. All are types of carbohydrate molecules made up of glucose bound by bonds, which are indigestible to mammalian enzymes. However the microbial population in the horses' hindgut is able to break down these bonds and converting the fibres into utilisable energy. These microbes can digest virtually all of the pectin and only partially digest the cellulose and hemicellulose. Lignin is totally indigestible to the horse.
As you would guess from the various types of fibres digestibilities, fibrous feed which is higher in pectin's, cellulose and hemi cellulose and low in lignin is a lot more digestible and have a higher energy level.
A simple guestimate on the digestibility and digestible energy content of a fibre feed is a simple grab test. If the feed is soft on your hand it is more likely to be more digestible and higher in energy as it will have a higher content of pectin, cellulose and hemi cellulose. The harder it is to the touch the less digestible and the lower the energy content is as it will have a higher content of lignin.
There are certain feeds, which are quite high in the most digestible fibre, pectin. Soybean Hulls are one such feed, which is high in pectin fibre. Since pectin is virtually totally digested by the horse, the feeds fibre level can remain high but also have a moderate level of energy, so much so that soybean hulls can have a similar energy level as some oats whilst having fibre levels similar to lucerne hay. For this reason feeds, which are high in pectin's, are often considered "super fibres".
The simple answer is NO. Horses evolved on fibrous feed and as such forms a symbiotic relationship with the micro-organisms in the horse's hindgut. Without fibre the bacteria population will be dramatically reduced, the flow of digesta through the digestive tract will change and also the horses eating habits will change from a constant grazing action to a few quick meals a day. This type of diet can lead to stable vices such as cribbing or chewing to more serious problems such as ulcers, colic and acidosis.
Most nutritionists suggest you should feed at least 1% of your horse's body weight per day in roughage. Roughages are feeds, which are high in fibre (<20%). This means for the average 500kg horse you would feed at least 5kg of roughages such as hay, chaff or pasture per day. Remember this is a minimum per day. If the horse is spelling or in light work most of its diet should come from roughages with some small supplementation to maintain vitamin and mineral balances. When a horse is in medium to intensive work it may be a struggle to get the horse to consume enough feed to meets its energy demands. This is why we feed energy dense feeds such as grains and oils. Remember though to base you diet first on at least 1% body weight and then fill the gap with a more energy dense feed.
In Australia we are constantly in drought in some part of the country and as such hay, chaff and pasture availability and quality can be a major problem. Apart from planning and securing sufficient roughage, there are several feeds, which can be used to substitute into your horses diet.
Highly lignified (stalky) feeds such as straw and some cereal hay are not very nutritious but they keep the horse chewing and the digestive tract moving. This will reduce the risk of stable vices and stomach ulcers.
Alternative feeds such as Hygain Micrbeet or pellets with high fibre levels around 16-20% are ideal as a substitute and partial replacement of traditional roughages. Hygain ICE has been reformulated as a high fibre low starch feed which is fully fortified with vitamins and minerals and is approved by The Laminitis Trust.
For more information of feeding fibre to horse and feeding the laminitc horse please contact HY GAIN FEEDS on 1300 HYGAIN (494246) or email us.
