College of Agriculture, Food and Rural Enterprise (CAFRE) dairy advisors have issued guidance to milk producers in Northern Ireland on how to best manage a multi-cut silage system.
Richard Gibson confirmed that 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,” he said.
“Although cutting earlier will reduce yield per cut, quality in terms of protein, digestibility and metabolisable energy 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 DM value.”
Rapid wilting
According to Gibson, rapid wilting is essential, as sugar levels start to decline as soon as the grass is cut.
Wilting increases DM and reduces clamp losses from effluent.
After cutting, there is a two hour window when the stomata of the plant remain open and water loss is at its greatest; about 100L/t of grass every hour.
Gibson commented:
“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.”
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. Farmers should discuss the effect of the lighter cut on price with their contractor.
Dry Matter increase
A 1.0 MJ/kg DM increase in metabolisable energy is generally achievable when moving from a traditional to multi-cut strategy.
DM intakes can increase by over 1.0kg/cow/day when feeding this forage. This enables an increased target for milk produced from forage.
Increased milk production from home grown sources will reduce concentrate requirement and therefore more than pay for the extra contracting costs of cutting more frequently.
With reduced cutting intervals, farmers should pay special attention to crop nutrition to ensure all the nitrogen is absorbed before harvesting. Apply slurry immediately after harvesting.
Fertiliser
Fertiliser should also be applied as soon as possible and not more than 2.5kg nitrogen (N) per hectare (two units per acre) for each growing day between cuts.
As crops are lighter, it is also important to consider how long the crop is wilted for. 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 5cm will therefore help with ensiling and fermentation.
To maintain rumen health, the diet may need to be supplemented with extra fibre such as straw or haylage.