Choosing Roughage

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Published in Horses and People Magazine

Quality versus quantity

By Mariette van den Berg BAppSc.(Hons), MSc. (Equine Nutrition)

Managing your pastures to provide enough forage for your horses would be ideal; however, in reality not many horse owners have the capacity to maintain horses on pasture as well as harvesting roughage to preserve for lesser times in the year. Moreover, in parts of Australia, the conditions are not favourable for growing enough fresh grass or forages. This means that you have to shop around for your roughage. In this chapter, we discuss the selection and use of various types of roughage and the importance of quality versus quantity.

Introduction

We have already pointed out that fibre and forages are important to horse diets. Horses must consume forages regularly to maintain proper digestive function. At least 50% of the diet of the horse must be in the form of fresh, growing grasses or browse or dry/moist ensiled hay or chaff.⁽¹⁾

Identifying the quality of roughage and using it effectively is one of the biggest challenges that horse owners face when selecting roughages. Many horse owners select roughage without evaluating if it is suitable for their particular horses. In particular, owners tend to rely on large amounts of lucerne as a main roughage ingredient without having a good look at their horses’ genuine nutritional needs.

Quality versus quantity

One of the first questions we must ask is: ‘What defines the quality of roughage?’ Characteristics such as nutrient profile, digestibility, leaf-to-stem ratio, smell and appearance, cleanliness (free of toxic weeds, dirt, and trash), and natural colour determine the condition of the roughage.⁽¹⁾ When we talk about the quality of roughage, we refer primarily to its nutritional value (energy, protein, soluble sugar) and digestibility. Nutritive value and digestibility are affected by maturity and harvest time. When forages are cut at a mature growing stage, the roughage is very ‘stemmy’, which makes it less digestible and nutritious due to the higher levels of less-digestible crude fibre and lignin.⁽²⁾ Higher quality roughage is finely stemmed, soft, and leafy, and is more readily digestible. Interestingly, high-nutrient-quality roughage can be as unfavourable as poor-nutrient-quality roughage — depending on which nutrient requirement perspective you take. For our working, breeding, and growing horses, we tend to provide high-quality forages to meet their elevated nutrient requirements. But for horses that are not working, are easy keepers, are obese, or are sensitive to developing laminitis, we might select poorer-quality forages.⁽³⁾

If we consider the evolution of the horse, we find that horses have developed a feeding strategy whereby they consume large quantities of poor quality forages (low energy and high fibre).^(2,4) So, from an evolutionary point of view, poor quality forages that provide lower energy, some protein, and high fibre (structural carbohydrates) are not a bad choice. However, studies report that high amounts of poor quality roughage can increase the chances of impaction colic in horses. This is likely to be associated with feeding mismanagement rather than the nutrient quality of the roughage itself.⁽²⁾

As soon as our horses are working, breeding, and growing, the quality of their roughage needs to improve to meet their daily nutritional needs.⁽⁵⁾ High-quality roughages tend to have a higher energy and protein content compared to lower-quality roughages. Depending on the type of high-quality roughage, they also can contain higher levels of vitamins and minerals.⁽¹⁾

Production processes

Hay & chaff

Producing hay is dependent on weather conditions, because hay is cut and left in the field to dry out in the sun. The temperature, wind speed, and sunshine level determine the speed of the drying process. Hay must be turned regularly — at least once a day — to make sure that it dries evenly, otherwise parts of the hay remain wet. Hay with too high a moisture content, and which is baled, can start to ferment in the centre of the bale. This produces heat and causes damage from bacterial breakdown and moulds. These bacteria and fungi can produce mycotoxins that are harmful for horses.^(2,5)

Chaff is finely chopped cereal or legume hay; most common chaffs are wheaten, oaten, and lucerne chaffs. Most of the chaffs are added to the concentrate/grain ration to increase fibre intake and chewing behaviour in horses.⁽¹⁾ Chaffs can be dried under controlled conditions (part of their processing) before being bagged.

Haylage & silage

Haylage is made from the same pasture grasses or legumes as hay, but instead of being allowed to dry out completely, it is baled when the moisture content is still relatively high (about 45–50%).⁽²⁾ It is wrapped in multiple layers of plastic to exclude all air from the bale and to allow a mild fermentation process using fungi and acid-producing bacteria. The bales are preserved for one week or more before they can be safely fed to horses.

Silage is when the hay undergoes a more complete fermentation process. Silage can be made from a variety of crops, such as corn, oats, and pasture grasses. The moisture content of silage varies from 60–80%.^(2,5) Silage is primarily fed to dairy and other cattle. Silage has an acidic smell, and horses tend to readily consume it. For horses, silage must have a green to yellowish colour and a pleasant acidic smell; very dark green or brown silage that is too dry or too wet is not suitable for horses.⁽²⁾ Silage must not be fed in large amounts to horses because it can cause digestive disturbance.

Because of their higher moisture content, both haylage and silage can be good feed products for horses that are sensitive to dust in hay. Studies have shown that they can reduce respiratory allergies in those horses.

Hay cubes

Hay cubes are made by compressing hay into small square blocks or pellets (5–4 square centimetres). Most hay cubes are made from lucerne or meadow hay. Cubes can be used effectively when certain classes of horses need supplemented feed or when conditions are less than ideal for feeding grain mixes. It has been reported that horses may choke on the cubes; therefore, it is important to dampen the cubes prior to feeding if your horse tends to eat quickly.

Choosing roughage

You can choose from many varieties of roughage. Local availability influences the popularity of a particular variety of hay in any geographical area. In Australia, lucerne hay/chaff tends to be the most popular.

Grass hay

Grass hays are a mixture of grasses that vary in their nutritive value and palatability, depending on the grass varieties, growing site, and stage of maturity at harvest time. Grass hays generally have a lower energy, protein , and higher fibre content than good-quality legumes. Top-quality grass hays can contain as much as 15% protein, whereas average hay has a protein content closer to 8% or less.^(2,5) In Australia, we can find a variety of grass hays and small-grain hays such as cereal hay/chaff (oaten, wheaten, millet), meadow hay, clover hay, timothy hay, tall fescue hay, Rhodes hay, and others.

When selecting a hay variety, you should review the nutritive value (see table 1). In particular, analyse the NSC content (fructan, starch) of hays to determine if they are suitable for horses with a metabolic disorder such as Cushing’s disease, insulin resistance, obesity, or laminitis.⁽³⁾

Legume roughage

Legume roughage includes lucerne and clover. Lucerne hay/chaff is most used in horse feeding. The nutrient quality of lucerne hay depends on its maturity at harvest (table 1). The highest quality lucerne comes from the cut plant before it becomes overly mature.⁽²⁾ Lucerne hay products generally cost more than grass hays per kilogram of dry matter, but per kilogram, crude protein basis, lucerne may actually be cheaper than grass hays.

Horse owners like to feed lucerne to horses because they usually eat it readily and it can supplement poor pastures. All horses, but particularly working, growing, breeding — and even older horses — can benefit from the high nutrient content. In practice, the majority of nutritional diet analyses show that horses are overfed protein and/or energy, which is mostly due to their consumption of large amounts of high-quality roughage. Therefore, we suggest that you assess the nutritional needs of your particular horse. A combination of grass hays and lucerne hay is a good management practice for most studs and horse facilities.

Other types of roughage

Other types of roughage can be straw, hulls, browse, or other fibre foods.^(1,2,5) These are not used as a full replacement of traditional roughages, but as a supplement to the diet to increase fibre intake. In drought season, grass and lucerne hays can become more expensive or even unavailable. Some of these products can be added to the diet to provide enough fibre.

Oat and wheat straws are low in palatability and feeding value for horses. Ponies have been shown to maintain body weight when more than 50% of their diet comprises straw; however, we recommend no more than 10% of the diet as straw, because it can reduce energy content and digestibility.⁽²⁾

The most common hulls and seed coats used are oats, rice, sunflower seeds, and soy beans.⁽¹⁾ These are low in energy and high in fibre. You can add them to the concentrate/grain mix to replace cereal chaff. Hulls and seed coats can be dusty — so dampen the products prior to feeding.

Using various types of fodder from trees and shrubs can also increase the roughage intake of horses. In the previous section, we offered more information about the use of forage trees and shrubs for this purpose.

Other fibre sources that you can feed to horses include copra meal, rice bran, and beet pulp. These products are mixed into the feed ration of your horse and should not be fed by themselves to replace roughage. Check the nutrient profile of these products before using, because they vary in energy, protein, fat, and NSC levels.

The type of roughage most suitable for your horse depends on your horse’s nutritional requirements, the availability of roughage products in your area, and the nutritive value of roughage. Evaluating your horse’s diet and analysing your hay/roughage will help you to feed your animals more efficiently.

Table 1: Average nutrient content of some varieties of roughages and feed products (as fed basis).

Further reading:

1.      Nutrient Requirements of Horses (NRC). 2007. 6th revised edition. National Academy Press, Washington DC, USA.
2.      Frape, D. 2010. Equine Nutrition & Feeding. Wiley-Blackwell; 4th edition; UK.
3.      Pollitt, C. & Watts, K. 2010. Equine Laminitis: Managing Pasture to Reduce Risk. Rural Industries Research and Development Corporation (RIRDC) publication no:10/063, Australia.
4.      Harris, P.A. 1999. How Understanding the Digestive Process can Help Minimise Digestive Disturbance Due to Diet and Feeding Practices, In: Harris, P.A., Gomarsall, G.M., Davidson H.P.B., Green, R.E. (Eds.), proceedings of the BEVA Specialist Days on Behaviour and Nutrition. Newmarket, Equine Veterinary Journal 45-49.
5.      Lewis, L.D. 1996. Feeding and Care of the Horse. 2nd edition, Lippincott Williams & Wilkins, USA.

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