Background
Before they were domesticated by humans, horses grazed almost day and night, spending up to 16 hours a day chewing on nutritious grasses and herbage. This supplied them continuously with small amounts of high-fibre forage. As rich was the grass was in fibre, it had little sugar and protein. The selection of herbage and grasses available to them was so diverse that they were nevertheless able to meet their vitamin and mineral requirements. The natural diets of horses were therefore high in fibre and rich in vitamins and minerals. By contrast, these diets were low in sugar and protein.
Much has changed since the domestication of horses. Forage now contains more energy and protein. In addition, pastures hold a smaller variety of herb species, meaning a more limited supply of vitamins and minerals.
Horses are true herbivores. Although the lives of domesticated horses and wild horses look completely different, their digestive systems have remained the same. The entire equine digestive tract is built to digest high-fibre food, i.e., the stomach is small, and the gut is well developed for digesting roughage. So ensure that your horse gets plenty of it.
What is roughage?
It is commonly thought that grass and its dried forms (hay and haylage) are the only sources of roughage for horses. However, there are many other types of feed that can be classified as roughage. Roughage is, by definition, forage with a fibre length of at least 8 mm. The fibre length is important for the feed to pass through the digestive system. Shorter fibres (for example high-fibre cereals) are also broken down into volatile fatty acids in the large intestine but do not assist in the feed’s passage. Examples of roughage are pasture grass, hay, haylage, beet pulp, straw, lucerne, etc.
Many English speakers use the terms “forage” and “roughage” interchangeably. However, it is important to know that roughage comes in different forms.
- High-fibre forage made from the entire plant (with the exception of the roots)
- Fresh: Pasture grass
- Harvested and stored: different storage methods determine the type
- Straw:
- Stems of cereal plants
- Storage = dry
- Dry matter (DM) > 85%
- Hay:
- Plants from the families Poaceae (grasses) or Fabaceae (legumes)
- Storage = dry
- Dry matter (DM) > 85% (average 86–92%)
- Haylage:
- Plants from the families Poaceae (grasses) or Fabaceae (legumes)
- Storage = airtight → fermentation
- 50% < Dry matter (DM) > 80%
- The percentage of dry matter in horse feeds is normally 70–80% DM!)
- Silage:
- Plants from the families Poaceae (grasses) or Fabaceae (legumes)
- Storage = airtight → fermentation
- Dry matter (DM) > 50%
- High-fibre feed that is not made from the entire plant
- By-products of certain crop plants
- Beet pulp: By-product from the manufacture of sugar from sugar beets
- Straw
- Oat and spelt husks
- Linseed husks from linseed industry
- etc.
The importance of roughage
Fibre length is important. The longer the fibres (> 2 cm), the longer the horse must chew, and the more saliva will be produced. And that’s healthy. The microorganisms in the gut also need roughage and a healthy balance of microflora depends on an adequate supply of fibre.
Roughage is an important component of a horse’s feed ration. No matter whether they are in regular work or ridden only occasionally: a horse’s feed ration should generally consist of 75–80% roughage. Horses need fibre. Fibre supports a healthy gut microbiome and is important for the passage of feed through the digestive tract. Fibre is also important for a healthy fluid balance in the large intestine. Fibre binds water, which is extremely important for sport horses.
Why is roughage analyses important, and what is analysed? The Cavalor approach
The composition of roughage varies. Its nutritional value depends on several factors.
- Plant species
- Soil quality
- Plant maturity (young plants, flowering plants, etc.)
- Leaf/stem ratio
- Water/nutrient availability
- Fertilisation
- Sunlight
- Harvest
- Conditions at time of harvest (dry or damp)
- Storage
As roughage makes up the largest share of the feed ration (it should correspond to at least 1.5% of the horse’s body weight), it is important to know which type of roughage (hay or haylage) is being fed to the horse.
The values within individual types of roughage can also vary. The amount of protein, fibre and sugar in hay may fluctuate greatly ((∆ + 200%), as can the moisture content in haylage.
If you buy hay or haylage in large quantities (e.g. 1–2 x per year), you may want to have it analysed in a la- boratory to learn what’s in your horse feed and what kind of adaptations you may need to make to the feed ration.
Roughage analyses are not practical if you have little storage space and therefore buy your feed on a weekly or monthly basis.
A standard laboratory analysis (NIR) will include analysis of the following:
- Dry matter (DM) and moisture content
- Crude fibre (ADF, ADL, NDF)
- Crude protein
- Crude fat
- Sugar
- VEM / EWpa (energy)
If there is doubt about the feed’s storage or if a stable has experienced many cases of colic, it may be ad- visable to have the feed tested for moulds, especially in the case of haylage or silage.
We normally do not opt for a mineral analysis. Such analyses are expensive and offer little added value for most customers. The mineral amounts provided by FRASC (based on average values of over 1,000 hay analyses per year) will generally correspond quite closely to the results of a paid analysis.
When is it sensible to do a full mineral analysis?
-
If a deficiency is suspected, a comprehensive analysis can be carried out after testing the feed ration in FRASC.
Example: Stables with a high number of bone anomalies, lame horses, joint problems, etc.
-
A comprehensive analysis may be helpful for stables where it can make a significant difference.
Example:
• Large facilities (> 30 horses) which want an in-depth feed ration calculation, including minerals.
• Breeding facilities that want everything to be perfect and are prepared to invest in the use of balancers. -
Facilities with a conspicuously high number of pregnancy losses would do well to consider testing for moulds and heavy metals.
Vitamin analyses are also not practical. 3-month-old hay will contain only 30% of the protein it had when it was cut.
Roughage analysis evaluation
Dry matter (DM) and moisture content
Roughage consists of dry matter and moisture content.
The sum of the percentages of moisture content and dry matter always equals 1.
The percentage of dry matter (DM) in the roughage determines the minimum kilogrammes of forage the horse should be fed each day. The recommended amount of dry matter from forage is 1.25% of body weight.
In practice, with relatively dry forage, i.e., no haylage or silage, this corresponds roughly to at least 1.5% of body weight in forage.
In practice, sports stables often feed too little roughage. Do the exercise and see whether the horses are getting enough roughage.
Example:
A 600 kg horse must eat at least 1.25% dry matter from forage per day. The average dry matter content of hay is 83%.
The average dry matter content of haylage is 70%.
|
Recommendation 1,25% |
Kg DM / day | Divided by DM% | Kg product / day |
| 0.0125 x 600 | 7.5 | 0.83 | 9 kgs hay |
| 0.0125 x 600 | 7.5 | 0.7 | 10.7 kgs haylage |
Attention!
Haylage with a higher moisture content (> 30%) is more susceptible to moulds. The higher moisture content also means that the horse will have to be fed more.
Crude fibre (ADF, ADL, NDF)
Crude fibre measures the structure of roughage. The more structure, the better. The crude fibre content is determined through ADF, ADL, and NDF.
Crude protein
Hay with a high protein content (over 12%) is not particularly recommended for elite sport horses but is quite suitable for brood mares and foals.
Sugar
Hay with a high sugar content (over 12%) is not suitable for horses prone to muscular problems, horses with insulin resistance, or horses prone to laminitis and Cushing’s.
Crude ash
Crude ash is a measure of the quantity of minerals in roughage. The crude ash can also be influenced by the amount of sand (= non-absorbable silicon) in the roughage. Does the forage have a high crude ash content? If so, it may also contain a considerable amount of sand, which can lead to sand colic. If this is not the case, it may simply mean that there are high levels of minerals in the stable.
Crude fat
Crude fat is not relevant in hay. Young grass has a high omega-3 content.
