Silage has now been harvested on the programme farms, either as the main crop of first cut or as bales made from surplus grass on the grazing platform.

With the weather having become more changeable in the past week, taking the opportunity to harvest grass in May has proved to be a good decision.

Silage made in mid- to late May will have a high feed value, as well as being more digestible due to grass being harvested before it turned from leaf to stem and seed.

Weather conditions during May were ideal for silage harvesting, with plenty of opportunities to wilt grass for a 24-hour period between mowing and ensiling

On the programme farms, high-quality silage has been shown to be an effective way to limit the use of purchased concentrate feed while maintaining animal performance in cattle.

Weather conditions during May were ideal for silage harvesting, with plenty of opportunities to wilt grass for a 24-hour period between mowing and ensiling.

This will have increased the dry matter content of grass, making silage a much more consistent feed due to less water being present.

An additional bonus when harvesting silage this year has been grass yields. Grass growth has been good throughout the spring, leading to heavy crops of grass being ensiled.

Forage budgets

Before closing off grassland for second-cut silage, it is a good idea to complete a simple fodder budget to predict if there will be sufficient forage harvested for winter feed. This exercise will give an early indication if additional ground needs to be closed off for silage or whether a third cut is necessary.

Most farms will work to a six-month winter of 180 days, which would cover from late October to late April

To complete a feed budget, start off by working out what cattle are likely to be on farm this winter and how much silage they will consume.

Most farms will work to a six-month winter of 180 days, which would cover from late October to late April. An example of a fodder budget is outlined in Table 1.

Feed intakes

Spring-calving cows that will be dried off for winter will typically eat 30kg to 35kg of silage daily. This works out at approximately 1t per cow every month.

This can be increased or decreased to suit cow size and body condition. Animals in good condition can be restricted to 20kg to 25kg in mid-gestation, before building up to ad-lib levels just prior to calving.

Weanling cattle will consume around 0.75t/month

For autumn-calving cows that are suckling a calf, intakes will be more typically be 45kg to 50kg or close to 1.5t per cow every month. Silage intake will be reduced where higher levels of concentrates are fed.

Weanling cattle will consume around 0.75t/month, with finishing cattle on high levels of concentrates consuming a similar amount of forage.

Calculate silage requirements as per Table 1. Once completed, you should work out how much silage was ensiled in the first cut.

Silage stocks

On farms where all silage is harvested as bales, this is a straightforward step. Count all bales and assume an average weight of 800kg to 900kg based on a dry matter (DM) of 35% to 40%.

Where silage was ensiled in the pit, calculate the volume of silage by measuring the pit. Measure the length, width and average height of grass in the clamp to calculate the volume.

To convert cubic metres to tonnage of grass, multiply by 0.53 for grass at 35% DM or multiply by 0.64 for grass at 30% DM.

For example, a grass clamp measuring 25m x 12m x 2m will have 318t of 35% DM silage on a fresh-weight basis.

Note that with high-quality silage, cattle will require less forage due to the increased feed value. Therefore, daily feed allocations can be reduced to the lower quantities outlined.

Closing off for second cut

After completing the fodder budget, you should have an idea of how much silage is required for winter feeding and whether or not there will be a fodder shortage.

If a deficit is likely, there is sufficient time to address this issue by growing more grass over the summer.

If additional silage ground cannot be closed off for second cut, then there is the option of taking a small third cut.

Once first-cut grass has been harvested, it is important to get slurry and fertiliser applied as early as possible to kickstart grass growth

An alternative is to increase fertiliser applications on grazing ground and take out surplus grass as baled silage.

Once first-cut grass has been harvested, it is important to get slurry and fertiliser applied as early as possible to kickstart grass growth.

One positive from harvesting silage in mid- to late May is that silage aftermaths are quick to green up again, as the plant is still in a vegetative phase.

Silage ground closed off in the next week will be ready to harvest again in late July. This gives adequate time to close off ground for a small third cut.

If a third cut is not required, then this ground can rejoin the grazing block by August.

Yields

Second-cut silage tends to be lower yielding than first cut. On the programme farms, the target is to get around 7t to 8t/acre of silage harvested with second cut.

A late first cut will result in slower regrowth, which will reduce the amount of grass grown for second cut

Yields will vary with fertiliser rates applied and growing conditions. However, delaying first-cut silage in order to increase the tonnage of grass harvested will have a negative impact on the yield of second cut.

A late first cut will result in slower regrowth, which will reduce the amount of grass grown for second cut.

Therefore, once weather permits, first cut should be harvested and fertilised immediately for second cut.

Fertiliser

For second-cut silage, applying 80 to 90 units/acre of nitrogen should suffice.

However, where slurry is being applied, the availability of nitrogen is lower compared with slurry applied in early spring.

Therefore, you will still need to apply up to three bags per acre of bagged fertiliser.

Applying a compound NPK product containing sulphur is advisable on silage ground to maximise yields and replace the nutrient offtake in first-cut silage.

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