Written by Antoinette Foster BSc Nutrition Dip. Nut. Equine Nutritional Therapist, Medical Herbalist

©2018

How often do you think about having your hay tested, having a better understanding of the hay you are feeding your horse may be of benefit? When you receive your analysis, you will notice that there are several abbreviations listed these may include WSC and starch. It may also include ADF and NDF or NSC.

So, what are these abbreviations and what do they mean? More importantly are they relevant to you the horse owner. The abbreviations ADF mean acid detergent fibre and NDF means neutral detergent fibre these measures of the hay are the cell walls or structural carbohydrate constituents. Neutral detergent fibre is the insoluble carbohydrate portion which remains after a sample of feed has been Refluxed in a neutral detergent solution. This Is a technique involving the condensation of vapours and the return of this condensate to the system from which it originated. It is used in industrial and laboratory distillations. This is made up of hemicellulose, cellulose and lignin these all give the plant inflexibility. The remainder after this process has been completed, is then refluxed in an acid solution. After this process only cellulose and lignin remain or in other words ADF.

Unfortunately, this is not an entirely accurate procedure as in many cases residues can be contaminated with carbohydrates such as pectin’s these are non-structural carbohydrates NSC.

ADF, NDF, and feed quality 

As a plant ages the amount of fibre increases however the protein decreases as a percentage of the dry matter, starch and simple sugars also tend to decrease.

The fibrous carbohydrate portions also require microbial fermentation in the hindgut of the horse, the energy in a more mature plant is considered less obtainable. This could be quite beneficial if you are feeding a horse that is a good doer as these horses generally require a lower non-structural carbohydrate level. So, the more mature the plant the more likely the hay will provide less calories and contain less NSC.

In ruminant nutrition NDF is used as an indicator for hay consumed as cattle naturally consume less hay when the NDF content is high. NDF could be used in a similar way with horses however the anatomical differences between equine and ruminant digestive tracts would suggest that it would not be very accurate.

ADF and NDF in Horse Diets

As a guide when NDF and ADF are high, they would not be a good choice for weanlings and lactating mares as there is a much higher demand on nutritional content for these types of horses.

Hays that have a content of 40 to 50% NDF and a content of 30 to 35% ADF would be considered quite ideal for performance horses, young growing stock and broodmares. For horses that are mature and are in light work and those who are good doers, they will benefit from hays with slightly higher values. Hays that have an NDF of over 65% and ADF of more than 45% will have a much lower nutritional value for horses.

So, you can use NDF and ADF values from your hay analysis to calculate more accurately your nutritional requirements.

Below I have added a list of abbreviations and descriptions of what will be contained in the average hay test.

Dry Matter (DM)– This tells you how much of the sample is left after water is removed. It is the moisture or dry matter content of the sample. Hay will generally be about 89 percent dry matter or greater.

Digestible energy (DE) – This is a measure of the digestible energy in the hay.

Total Digestible Nutrients (TDN) - This is a measure of the total digestible nutrients in the hay or its energy value. TDN may be used in place of DE or offered in addition to DE. It may range from 40 to 55 percent.

Crude Protein (CP)– This is a measure of the protein concentration of the hay and can range from 6 percent to 8 percent in native grass hays to about 15 percent or higher in high quality legume hays. Neutral Detergent Fibre (NDF) – This is a measure of the plant’s cell wall content, shown as a percent. The higher this is, the less hay the horse will eat.

Acid Detergent fibre (ADF) – This is a measure of the fiber concentration of the hay, shown as a percent. As ADF increases, digestibility and nutrient availability decreases.

Non-Structural Carbohydrates (NSC) – This is a measure of the non-structural carbohydrates in the feed

Starch and Sugar- This is a measure of sugars and starches in the feed. 

Many parts of Australia are experiencing very low or no rainfall, and subsequently, very poor pasture growth or completely bare paddocks. We have been getting a lot of questions from horse owners with little or no pasture, on how best to replace the grass component of their horse’s diet. The choice of possible hay types, given the current season, may be more down to availability than any other factors, but where available, good quality pasture/meadow/grass hay is normally a good starting point. No matter what sort of hay you can get (and provided your horse or pony doesn’t have any additional issues affecting hay type/consumption), the guidelines around amounts generally follow the same rules.

Drought and feed prices!

 Very importantly Australia is experiencing a severe drought, no doubt as a horse owner you would have experienced a substantial increase in the price of horse feeds and hay prices. Unfortunately, there is no way around this, as prices of alfalfa and oaten hay have more than doubled in the last 4 to 5 months, oats and barley have also doubled in price. The increased price of feeds and Hays have been felt Australia wide. There is no respite from the drought, it is unlikely that these prices will drop in the foreseeable future. If you are located in an area where you have not been drought affected, you are indeed very fortunate.

What is the best hay to feed your horse? 

We already know that there are certain types of Hays that have a much higher nutritional value than others. There are Hays that have become more prominent recently in particular for horses that are prone to laminitis and for those horses that put-on weight very easily. Hays such as Teff and Hays that have a lower sugar and starch content have become quite popular. I personally love alfalfa hay as it is very nutritious but also contains an excellent level of protein which sits between 19 to 22%. However, the wonderful thing about alfalfa is that it is very low in NSC and starch, making it an ideal feed for horses that suffer from EMS, which include Cushing’s disease, as these horses require a good level of protein and a high level of fat in their diet. Horses who are prone to laminitis and are easy keepers may also benefit from being fed alfalfa, as it will not be necessary to feed high levels, but the nutritional value will benefit these horses. Other forms of hay which include pasture hays may vary in the level of NSC and starch so it is always recommended to have these hays off the farm tested. I am not a fan of wheaten hay for horses as I prefer a more natural approach to feeding.

How much hay should I feed?

Horses need to eat a minimum of 1-1.5% (on a Dry Matter basis) of their body weight in roughage per day just to keep their gut happy and healthy. Most hays contain around 85-90% dry matter. Horses will typically consume between 2-2.5% of their body weight overall each day as a combination of pasture, hay and hard feed (though we have all come across some notable ponies who are out to set the record for more). Ideally, most horses and ponies should receive 70% roughage (or more) as part of their daily diet. We have attached an easy reference table with the minimum roughage and average total feed intakes for most sizes of horses and ponies.