17 November 1995

Keep silage spoilage down

This seasons high dry matter grass silage will need careful management, as

Jessica Buss reports

HIGH dry matter grass silage needs careful management to avoid waste through spoilage in the clamp, warns Suffolk-based Signet consultant Geoff Fish.

He urges producers to be aware that dry silage can be prone to waste – a risk more typical of maize silage.

He also warns of the danger from long-term exposure to mould spores, that can be found in dry silage, causing respiratory problems such as farmers lung in workers (see p37).

"This year many silages have good analyses but because they are dry, air penetrates more easily. This allows any yeasts and moulds present to grow and ruin it," says Mr Fish.

"When silage is heating up use it more quickly and change to other feeds later. Also use wetter silage or narrower clamps first during warmer weather as dry silage will deteriorate faster. With clamps that are heating up try to use six inches of the face a day.

"In another dry year consider using silage additives containing propionic acid or a bacteria to stop yeast growing and split wide clamps down the middle."

One of Mr Fishs clients, Northants beef and sheep producer Richard Edmondson, has fed a 37% dry matter second-cut grass silage since mid-August. Mr Edmondson of Home Farm, Wicken, started feeding silage when he began housing his 120 bulls on Aug 16 to save grazing for his 450-ewe flock.

He is aiming to keep waste of this high dry matter silage to a minimum for stocks are low with second-cut yields 50% down on previous years and no third cut. Pressed beet pulp (25-30% dry matter) is being fed at 7-8kg a head a day to eke out stocks.

He rolls back the top sheet as little as possible, to keep the pit sealed. "There is a little moulding on the shoulders but this only appears after the sheet is pulled back and it is exposed to air," he says.

"A block cutter helps to keep the face clean. We realised when feeding silage in the summer a few years ago that we would need a block cutter to prevent heating and waste."

Mr Edmondson tidies up the sides and floor of the clamp when cutting from the face. "When these bits are not fed to cattle immediately they go off very quickly," he says.

His two narrow clamps give flexibility so silage can be made in one clamp while feeding from the other. It also means he can go across the face of the one hes using twice a week, so reducing waste.

Mr Edmondson has used silage inoculants for three years for he believes they are easier and safer to use than the sulphuric acid he used previously. He believes the inoculant stabilises the silage and stops it heating up in the trough.

Silage is put along the trough in blocks every three days. These are left for the bulls to pick at on the first day. On the second and third days silage is forked out along the troughs. After three days there is only about a wheelbarrow full to clear away, sayus Mr Edmondson.

"Feeding in blocks is simple, avoiding mechanical breakdowns that can occur with other systems," he says. "And with a forage box we would have to put silage out every day."

Hereford cross calves are bought at three months old (120kg) and are reared for 12 months on a grass silage system to a slaughter weight of over 500kg.

"Concentrates are currently fed at 2kg/day to younger animals and 3.5kg/day to older animals to achieve a daily liveweight gain of over 1kg a day and to finish animals quickly," he says.

&#8226 Narrow clamp faces.

&#8226 Short chop length.

&#8226 Sheet down clamps quickly.

&#8226 Use an additive that works.

&#8226 Dry matter: 37%

&#8226 Crude protein: 16%

&#8226 D-value: 67

&#8226 ME: 10.8 MJ/kg

&#8226 pH: 4.1

&#8226 Cropping: 223ha (550 acres) of arable crops, 10ha (24 acres) for outdoor pigs and 38ha (95 acres) of permanent pasture.

&#8226 Silage: First-cut 22ha (54 acres) and second-cut 20ha (49 acres).

&#8226 Stocking: 120 Hereford cross bulls, 450 ewes and 300 outdoor sows with progeny taken to bacon weight.

Silage is made by fermentation under anaerobic (air free) conditions. However, when the silage clamp is opened air can penetrate the face causing oxidation of sugars by yeasts. The sugars are then converted to carbon dioxide and water and this process generates the heat.

Richard Edmondson uses a block cutter to help keep the face clean and prevent spoilage of his high 37% dry matter grass silage.

Pressed beet pulp is fed to Home Farms Hereford cross bulls at 7-8kg a head a day to eke out silage stocks, which are low, with no third cut.