Guide to producing quality silage
- Ensure adequate interval between last N fertiliser application and proposed cutting date. The rule of thumb is 2 units per day.
- Test grass prior to cutting for nitrates.
- Ideally grass showed be mown in the afternoon when grass sugars are at their highest. It is best to start cutting after lunch and work late into the evening (avoiding dew) than first thing in the morning.
- Mow at 4” stubble height. This will reduce contamination, promote faster wilting and increase nutrient density.
- If a spreader mower is not used, ted the grass out immediately after cutting. This is essential for first cuts but depending on weather conditions may not be required for subsequent cuts
- Harvest at 30-35 % DM. This can be checked by weighing 100g of forage in a plastic container and then drying the sample in a microwave. Continue to dry the sample until it stops losing weight. The final weight is the %DM.
- Do not cut too little or too much acreage in front of the harvester. Match the area cut to duration of the campaign and the output of the forage harvester.
- Ensure that the rake is set at the correct height so not to rake up stones and soil. Best to do this in the Yard and then check again in the field.
- Do not rake up grass which will not be harvested in the same day. Large swaths left overnight heat up and gather moisture. The only exception to this rule is if too much grass is down infront of the harvester and there is a danger of it getting too dry.
- Apply an inoculant at the recommended rate. Use an inoculant that provides 1×106 CFU/g.
- Line the walls of the silage pit with side sheets that are sufficient length to reach the floor and long enough to be folded over the silage and reach the centre of the clamp or a minimum of 2m in from the shoulders (fig 1.0). Lay plastic drainage pipes along the bottom of the walls to carry away any effluent and rain water that runs down the side walls. A thin sheet on top of the silage will further reduce losses. This thin sheet is better than two thick black sheets.
- Vary the cut length according to the maturity and the DM of the crop. Very young leafy material should be chopped at between 30 to 40mm as should very wet material. Drier more mature forage should be chopped at around 25mm.
- Fill the clamp with thin layers of forage (15cm) and consolidate well. Use an additional roller tractor on the clamp. Regulate the speed of harvesting if insufficient time for rolling is a problem. Adequate time for consolidation should govern the speed of the harvesting operation.
- Ensure the area in front of the clamp is clean and free from contamination.
- Do not roll the clamp extensively at the end of the day or before starting in the morning. Apply a layer of forage before beginning to roll the clamp the next day.
- Avoid steep ramps and shoulders that are difficult to consolidate. Gradients above 30 degrees will not consolidate.
- Before sheeting apply clingseal followed by the side sheets and then the top sheet.
- Secure covers only work effectively on domed clamps. The sheet will need tightening daily following ensilage for a week or so.
- On flat topped clamps touching tyres or rubber mats will need to be used.
- Consider how the forage will be utilised in the winter/feeding period and store according to quality
Written by Dr Huw McConochie – Head of Dairy Technical Services
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