16 June 1995

Acreage on the increase

Danish dairy farmers have been making fermented whole-crop forages for 25 years. Fed alone or in total mixed rations they are giving some enviable milk protein figures as Michael Gaisford found on a tour of Jutland

DANISH dairy farmers now have 25 years experience of feeding fermented whole-crop silage made of barley, peas and wheat.

Today 40,000ha (100,000 acres) is harvested for fermented whole-crop and the acreage is rising each year due to the high production cost of the traditional Danish root crop fodder beet, the high EU cereal area payments for whole-crop cereals and peas and the milk protein boost from whole-crop.

Favourite crop, taking 58% of the fermented whole-crop area, is spring barley, usually undersown with a ryegrass/white clover mix. Barley/pea mixtures take 29%, with winter wheat only 13%.

The national area of fodder beet grown is 60,000ha (150,000 acres), while forage maize takes up 32,000ha (80,000 acres).

The feeding value of all the forages grown in Denmark in 1994 are shown in the table.

Typical dry matter yields for spring barley and spring barley/ pea whole-crop mixtures are 9t/ha (3.6t/acre), 12t/ha (4.8t/acre) for winter wheat and 8t/ha (3.2t/acre) for peas alone.

This year the payments in Denmark for spring barley, spring barley/peas, winter wheat and forage maize are £244/ha (£98/acre), while peas grown alone are attracting £352/ha (£141/acre).

"Whole-crop peas mixed with a whole-crop cereal in the silage clamp give a very good feed for high yielding dairy cows," says Martin Mikkelsen, senior adviser on forage crop production at the Danish Agricultural Advisory Centre, Aarhus, Jutland.

Also popular is the mixture of barley and peas grown together as a sole roughage, whole-crop barley fed with chopped fodder beet and winter wheat whole-crop fed with a variety of by-products.

"Many combinations of whole-crop forages are grown and fed here. The variations depend mainly on the soil type, availability of irrigation on light land and area of the country," says Mr Mikkelsen.

No additives used

Apart from the limited use of molasses on some farms, he says no additives are used in Denmark when making fermented whole-crop forages. Trials have been carried out making an alkali whole-crop with urea, common practice here, but it has been given a definite thumbs down by the Danes.

For fermented whole-crop made of winter wheat, he recommends short-strawed varieties like Hussar and those with a high resistance to fungal infection to cut the use of sprays. With long-strawed varieties, he recommends cutting only the top 50-60cm (20-24in).

He says the most critical decision is the timing of harvest. Trials have indicted that the optimum time is 5-6 weeks after heading starts. More precise timing is determined by testing the ripening grains, which at harvest should be at the doughy stage, not wet and creamy and not yet really firm.

At harvest whole-crop wheat should be chopped to a maximum of 2cm (0.8in) to get good clamp consolidation. "The higher the dry matter the more important the chop length," he says.

To feed out with minimum waste, he recommends that whole-crop is made into long, narrow clamps. "The clamp size must fit the number of cows being fed from it." Mr Mikkelsen also stresses the importance of filling the clamp in thin layers and carefully consolidating it as it is filled before sheeting with two layers of good quality 0.15mm plastic.

"Tyres are good enough on plastic for indoor clamps but outdoor clamps are best covered with sand and perhaps also netted."

And when feeding out he advises using sandbags across the top of the open face, which are pushed back as the silo is emptied to minimise air causing storage losses.

Colleague Rudolf Thoegersen, an adviser on cattle nutrition at Aarhus, says fermented whole-crop in Denmark is fed in a variety of ways, either as a separate feed, a mixed feed with grass silage or as part of a complete diet.

"Self-feeding of whole-crop is hardly ever practised in Denmark, but complete diet feeding has now taken over on about 10-15% of farms and is becoming ever more popular," says Mr Thoegersen.

Jorgen Larsen, Keenans nutritionist in Denmark, also sees a reduction in fodder beet interest because it attracts no EU subsidy, has a high labour requirement to grow and encourages butterfat production. "But whole-crop helps produce more milk protein, which is what the market wants today."

Mr Larsen puts Denmarks average milk protein level at 3.35%, with good farms feeding whole-crop and maize silage achieving 3.5% and more.

"And whole-crop is such a flexible crop to grow. If enough forage has been made by the end of July it can always be left for the combine. If it has been undersown the land will also produce an autumn cut of silage and some grazing." &#42


Analysis of Danish whole-crop, maize & grass silages 1994

CropNoHarvest DM.% DM content

samples date (ave)%C proteinFibreStarchD-value

Spring barley 3,64627/7449.823.425.568.6

Winter barley588/7419.825.120.566.4

Winter wheat68524/7499.622.329.469.9

Peas10424/74215.7n/an/a73.3

Barley/peas1,77226/74211.824.0n/a69.9

Forage maize1,1027/10319.519.6n/a75.6

1st cut grass2,2833/63415.527.3n/a75.5

Note: All samples analysed at same laboratory by NIR.