Carbohydrates

So what are carbohydrates?

Firstly, when discussing carbohydrates, it should be noted that there are two types of Carbohydrates found in the horses diet:

Fibre carbohydrates are known as structural carbohydrates and, for the most part, are provided by the grass and hay that the horse consumes. These carbohydrates are essential for the horse’s well being, and must always be provided. Thus an equine diet can never be totally carbohydrate free. The energy provided by structural carbohydrates is slow releasing and thus a ‘cooling’ source of energy.

On the opposite end of the spectrum we have sugars and starches, which are classified as Non-Structural Carbohydrates (NSC) and, for the most part, are provided by grain in the horse’s diet. Most of the NSC are broken down in the small intestine to become glucose, which is a simple sugar that provides energy. After being absorbed into the bloodstream, glucose is transported to various tissues of the body, where it is used as fuel immediately or stored as glycogen or as fat. The glycogen is stored in the muscles or liver, where it can be called upon as fuel when needed. NSC are commonly referred to as fast release energy sources and thus can cause some horses to become ‘hot’.

Are NSC evil?

No, but we know that overuse of such ingredients can have detrimental effects. We want the NSC to be digested in the small intestine, but if we feed a large meal that contains so much starch that it overflows from the small intestine into the large intestine, it may cause digestive disturbances such as colic or laminitis.

Studies have shown that feeding no more than 2kg of a concentrate food per meal (this is your bucket or grain feed- hay and grazing are not applicable to this restriction) will reduce the risk of grain overload into the horse’s hindgut, therefore reducing the risk of colic or laminitis.”

Most horses can cope extremely well with an average level of NSC in their diet. However, there are horses that require a much lower level of NSC to remain in a healthy condition. 

These horses include those suffering from or prone to laminitis, Cushing’s disease, Insulin-Resistance, Exertional Rhabdomyolysis (tying-up), ulcers, colic and even to some extent those horses that can be extremely ‘hot’. 

It is recommended that these horses be supplied with an alternative form of energy, or, in other words, a diet with a low level of NSC.  

 

How do I know how much NSC is in my concentrate feed?

This will really depend on your feed brand. Those companies focusing on NSC values will list them on their labels but with other brands you may need to contact them to request this information.

Be careful when comparing NSC values from brand to brand and remember to compare apples with apples. Some companies may specify as grams per kg (g/kg) and some by using a %.  However its easy to convert, for example:

200 g/kg NSC is the same as 20%.

Keep in mind that some companies may only give you a ‘starch’ value.

This is useful in determining how much starch (and in essence, how much of the feed) is made up of grains and grain by-products but this value doesn’t tell you how much sugar is in a product.

A low starch food may still have a high sugar content leaving you with a high NSC feed overall. Similarly a low sugar feed may still be high in starch also giving a high total NSC. It is therefore important to have both components of the equation.

NSC= sugars + starch

In terms of the level of NSC you are looking, the following gives a good indication:

NSC > 35% or 350g/kg = high

NSC  35-20% or 350g-200g/kg = relatively low

NSC  < 20% or 200g/kg = low

(figures determined by Kentucky Equine Research)

Note that for horses with conditions such as laminitis, Insulin Resistance, etc levels of  12-17% are considered more desirable.

Don't forget your roughage when considering NSC levels

Getting NSC values for roughage can be slightly tricky as generally most suppliers don’t have these details at hand.

The NSC value of grass also fluctuates throughout seasons and is dependent on the growing area.

You can send samples of your hay and grazing away for testing but this is a costly process.

Below are some values for various hay types but please note that these are an average guideline only and may not represent your particular hay/grazing:

Lucerne Hay = NSC 11%, Sugars 9.2, Starch 1.8

Oat Hay= NSC 23 %, Sugars 15.8, Starch 6.3

Mixed Hay= NSC 13.6 %, Sugars 10.9, Starch 2.7

Teff= NSC 8.5-12%, Sugars approx 8.6, Starch approx  1.4

If your are limited to the grass type you can get in your area, then soaking (fully submerging in water) your hay may be beneficial if you are looking at keeping NSC levels low.

Soaking hay for 60mins in clean water can reduce sugars significantly.

Warmer water will help to remove sugars faster, and the more water the hay is soaked in the more sugars are lost.

Changing the water half way through the process will also help to remove more.