The dos and don’ts of making silage

Silage making has come a long since its early use by the Greeks and Romans. Dr Clive Dalton of lifestyleblock.co.nz explains

The silage making process is very old. It was used by the Greeks and Romans and became popular on farms in the late 19th Century.

But you needed a pit or silo, and a lot of labour to feed it out, which meant it was not popular on small farms. With the invention of the baler and plastic wrapping, its popularity has changed dramatically so small farmers can take advantage of the benefits of silage as a supplementary feed for stock.

You don’t need a hay barn – the wrapped bales or long sausage bag can stand out in the paddock.

The end product is near the original pasture. You should only lose about 20 per cent of the nutrients in the silage making process. The high-protein green leaf is maintained. Now that it’s baled, you can buy and sell it. Unfortunately, it smells, and some people don’t appreciate this.

You must ensure a good fermentation when making it.

It’s difficult to cart and feed out without proper equipment.

The effluent from silage is an environmental hazard and is lethal to wildlife in waterways as it eats up oxygen.

Silage wrap is an environmental hazard – it needs to be put in an approved landfill and not burnt or buried on the farm.

You can lose up to 30 per cent of the original nutrients if it is made poorly.

Holes in the plastic (even pin holes) can let in air and allow moulds to ruin large areas. Rats love silage bales and so do stock. What happens in a good silage making process? You ensile a good quality crop at the right stage. When it is baled or put in a pit, a bacterial fermentation starts.

This should be in anaerobic conditions – for example, no air.

Make sure that in a pit the silage is consolidated by rolling all the time it is being filled.

With wrapped bales this is less of a concern as baling consolidates the grass and it is sealed immediately after baling.

This allows Lactobacilli and Streptococci present on the plant leaves to feed off the 3 to 3.5 per cent sugars present.

These are the good bacteria that we want. The silage smells sweet and like vinegar. What happens when things go wrong? There is no consolidation so you get an aerobic fermentation – air gets in.

The bacteria form a butyric acid fermentation which really stinks. You will smell ammonia and see moulds.

After a while in the stack or bale it will look more like tobacco, and is of very little feed value, in fact the stock probably won’t eat it.

The bales will shrink to half their original size – a good sign of trouble.

To make good silage, select a good rapidlygrowing crop high in ryegrass and clover.

Cut it at maximum of 10 to 15 per cent seed head emergence.

Don’t try to ensile short and lush spring pasture. Cut when dry on a sunny day, not in the rain. Have it cut and conditioned to spread it about to get rapid wilting.

Get rapid air exclusion in the pit. Seal the pit rapidly.

In a pit keep the temperature below 30 degrees Celsius by rolling to stop the plants respiring.

Use a pinch bar to make a hole and drop a thermometer on a string down the hole to check temperature.

Wrap bales soon after baling and transport them with care to avoid puncturing the wrap.