Feed needs should dictate silage cutting

The decision to cut grass silage should be made according to feed requirements, rather than the weather, advises Nickerson Direct.

After a record breaking dry spring and recent variable rain fall across the country, many farmers are increasingly anxious about grass cutting date, but they should express caution.

While it might be tempting to rush in, Nickerson Direct’s forage product manager Simon Broddle says the advice remains to let feeding requirements, not weather concerns drive the decision.

“We have growers asking ‘should we have cut before the rain?’ or, if they haven’t had significant rainfall, ‘perhaps we should go now?’. My advice is to consider your feeding needs first and plan for those before you get the mower out.”

Assessing your needs
For example, when planning on feeding wholecrop as a complementary forage to grass this winter then there is a good argument for cutting early. This will give huge quality in the form of protein, digestible fibre and energy – a good dietary complement to the wholecrop.

“If, on the other hand, you are feeding maize, then perhaps you need additional fibre, as most of your energy will come from your maize silage through sugars, digestible fibre and starch. In this case, there is an argument for a later cutting date.”

For those deciding to go early, Mr Broddle warns that young, dry grass is full of sugars so correct wilting of the cut crop becomes essential to avoid acidic silage.

Acidosis warning
“Sugars in wet silage will ferment to acid: the higher the sugars and lower the DM, the more acid will be produced. When you come to feed this silage, you then get reduced intakes, lowered rumen pH and, due to the low fibre, an increased risk of acidosis,” says Mr Broddle.

To avoid the risk of acidic silage, grass should be wilted to a minimum 28% DM to ensure sugar content is retained rather than converted to acid due to the low moisture content. Attention should also be paid to chop length.

“A simple rule of thumb is ‘the wetter the crop, the longer the chop’ but, in this case, we need to make the chop length as long as possible bearing in mind how difficult it may be to consolidate in the clamp. Dry, long silage is always more difficult to attain a good anaerobic environment, so keep it as long as you can with clamp management being the controlling factor.”

Nitrogen uptake
For those who have had rain and are now ready to cut, particularly as seed head is starting to appear in some crops, Mr Broddle advises being aware that the presence of moisture will mean a rapid uptake of nitrogen in grass.

“It’s not possible to know the N status of grass without testing. Excessive N levels can be an issue both in the clamp and the cow, but keeping DM in the mid to high twenties and good clamp management can avoid raised butyric levels.”

Grassland establishment and management will be just two of the issues farmers can discuss with technical specialists on the Nickerson Direct stand at Grassland 2011 on May 18-19, stand number 308. Visitors to the stand can also enter a prize draw to win 20 acres of Red Circle grass mixture, or can enter online.

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