In this article, Richard Gibson of CAFRE discusses a multi-cut silage system.
As we approach the silage season, paying attention to cut and wilt times will help boost quality and reduce dependence on concentrates through the winter.
Adopting a multi-cut silage system could help maximise quality and performance from the same acreage.
Although cutting earlier will reduce yield per cut, quality in terms of protein, digestibility and metabolisable energy (ME) will increase.
Cutting early and wilting rapidly to achieve a dry matter (DM) of 28-32% will significantly help milk from forage. For example, grass cut in early May instead of mid-May will be cut at a higher quality with a high D-value.
Rapid wilting is essential, as sugar levels start to decline as soon as the grass is cut. In addition, wilting increases DM and reduces clamp losses from effluent.
After cutting, there is a two-hour window when the plant’s stomata remain open, and water loss is at its greatest; about 100 litres per tonne of grass every hour.
After that, water is lost where the leaves are broken, or the crop has been conditioned.
As first cut is taken earlier in a multi-cut system, when weather conditions may not be ideal, tedding allows for air movement over the crop, helping evaporation.
1.0 MJ per kg DM increase in ME
Ideally, in a multi-cut system, the time between cuts is reduced to four or five weeks. Individual cuts will be lighter compared to the traditional system.
Therefore, it is worthwhile discussing the effect of the lighter cut on price with your contractor.
A 1.0 MJ per kg DM increase in ME is generally achievable when moving from a traditional to multi-cut strategy.
DM intakes can increase by over 1.0 kg DM per cow per day when feeding this forage. This enables an increased target for milk produced from forage.
Increased milk production from homegrown sources will reduce concentrate requirement and, therefore, more than pay for the extra contracting costs of cutting more frequently.
With reduced cutting intervals, pay special attention to crop nutrition to ensure all the nitrogen is absorbed before harvesting. Apply slurry immediately after harvesting.
You should also apply fertiliser as soon as possible and not more than 2.5 kg nitrogen (N) per hectare (two units per acre) for each growing day between cuts. As crops are lighter, consider how long the crop is wilted.
To achieve 28-32% in ideal weather conditions, 24 hours wilting should be sufficient. As the grass is leafier, fibre levels are low.
Increasing the chop length to 5 cm will, therefore, help with ensiling and fermentation.
To maintain rumen health, you may need to supplement the diet with extra fibre such as straw or haylage.
Clamp management is key to minimising loss of nutrients. If dry matters are desirable, you need to fill the silo quickly and distribute grass evenly.
The aim is to remove the air and make the clamp as airtight as possible.
Spread the grass in shallow layers and roll continuously. Ideally, cover the silo immediately, and the cover weighted effectively, paying particular attention to the shoulders of the pit.