Roughage

What is roughage?

Roughage is plant feed with a lot of crude fibre and long structure. It includes hay, straw, grass silage and, to a lesser extent, maize silage. The cow has to chew and ruminate the fibres. That is exactly why ruminants cannot do without roughage: it keeps the rumen moving and produces plenty of saliva, which buffers the acids in the rumen.

Roughage, forage, succulent feed

These terms are often mixed up.

• Forage is all basic feed that is grown on the farm and fed in large amounts: grazed grass, grass and maize silage, hay, straw, beet.
• Roughage is the part of the forage with a lot of crude fibre and structure, so hay, straw and silages.
• Succulent feed is forage with a high water content and little structure, such as beet, pressed beet pulp or fresh young grass.
• Concentrate supplements the forage with concentrated energy and protein.

Why does the cow need structure?

The rumen microbes ferment carbohydrates into acids. Without enough structure the cow chews less, produces less saliva and the rumen pH drops. The fibre-digesting bacteria decline, milk fat falls and rumen acidosis becomes a risk. Long fibres also form a fibre mat in the rumen, which holds back small feed particles and so improves digestion.

As a guide, the total ration should contain at least 16 to 18 percent crude fibre in the dry matter. Figures alone do not tell the whole story, though. Finely chopped silage does contain crude fibre, but little physically effective fibre. In practice it helps to look at the cows: at least half of the lying animals should be ruminating, and a cow ruminates for around eight hours a day.

Straw in the ration

Straw has little energy and a lot of structure. It is mainly used in dry cow rations so the cow feels full without getting too fat. For this to work, the straw must not be too long. At a chop length of 2 to 4 cm the cows can hardly sort it out. Put the straw into the mixer wagon before the silage and make sure it is good quality and free of mould. You can read more tips in Better calves through optimal nutrition in the dry period.

Checking forage quality

Forage quality varies with cutting date, weather, fertilising and ensiling. Grass cut early has more energy and protein, but less structure. Grass cut late has more crude fibre and is less digestible. So have your grass silage and maize silage analysed regularly, at least for every new clamp. For dry cows it is also worth testing for calcium, phosphorus, potassium and DCAB, because grass silage often contains a lot of potassium.

The better the forage, the less concentrate the cow needs for the same yield. That lowers feed costs and is easier on the rumen.

Roughage for calves

Calves need free access to hay or straw from their first week of life. It trains the rumen muscles, while concentrate makes the rumen papillae grow. In the first weeks, though, most of the energy comes from milk. Putting the focus on roughage too early slows growth, because the rumen cannot yet make good use of the fibres.

Frequently asked questions

All terms in the glossary