2013-04-24 xml
Reap that Big Bale Bonus!

Properly made, big bale silage is every bit as good as clamp silage, if not better says Volac’s Alistair Sampson. However, if you are going to get the most out of bales you must use grass of the same quality as you would put into the clamp.

Think about why we preserve forage: to conserve a stable and nutritious feed, with minimal loss of quality or quantity and to maximise the use of cost-effective home-grown forage. Following the past few difficult seasons efficient forage management ensuring best practise at each stage is essential to save on expensive concentrate feeds. Making more of big bales could help.

Properly made, big bale silage is as good as clamp silage, if not better,” Alistair Sampson of Volac

Properly made, big bale silage is as good as clamp silage, if not better,” Alistair Sampson of Volac

There are so many variables to forage-making that no grass silage crop is ever ensiled and eaten with 100% efficiency. However research into the nutritional value of silage indicates that when properly made, with the right materials and correctly stored, bale silage can be of the same or better quality, with fewer nutrient losses than clamp.

For example, trials at IGER compared dry matter (DM) losses from grass for both clamp and big bale silage and found greater losses from the clamp. See Figure 1.

Figure 1: Dry matter loss comparison (assuming 1,000 tonnes at 30%DM)


Clamp silage

Big bale silage

DM loss (%)

18% - 20%

0.2% to 13%

DM loss (tonnes)

54 - 60

0.6 – 39

Source: IGER

Main losses are in the field - mechanical, biochemical, leaching; during storage - fermentation, effluent, oxidation; and aerobic spoilage - once the bale or clamp is opened. Ultimately, the nutritional value of big bale silage will depend on the quality of grass harvested and the losses that occur during the fermentation and storage process.

Those losses stack up: for every 1,000 bales at 30% DM, each 1% DM loss is equivalent to 1.5t DM. Think of the cost of replacing that with bought-in forage or concentrate, the latter currently at £290/tonne.

The following seven point plan will help you to maximise each bale’s value and reduce losses.

1, Harness as much grass potential as possible: growth can vary from 66kg to 113kg DM/ha/day during May alone, so follow good crop management practices to encourage yields.

2, Cut at the optimum time, before grasses reach 50% ear emergence when D-values, protein and sugar levels are high. Poor quality grass will not make good silage whether in a bale or a clamp.

3, Wilt the grass for 24 hours to 25% to 50% DM to minimise effluent production. Remember, at 50% DM, half the bale is water, which means that for a bale of 650kgs, 325kgs are water. At 25%DM, the same bale would contain 487kgs water, so the higher the DM, the fewer bales to wrap and handle. This is a cost-saving in itself with less wrap required and less time spent baling, wrapping and moving bales.

4, Present the swaths well and apply net wrap to make even and compact bales.

5, Use at least four layers of high quality film to ensure that nutrients are fully protected in the bale, though the more layers the better and there has been a move towards using six layers in the past few years. New generation wrap such as Volac’s Pre-Tech Topwrap 2000 gives a more effective air-tight seal which encourages enhanced silage fermentation by keeping oxygen out of the bale.

For silage greater than 40% DM, wrap with minimum of six layers of high quality film. Note this recommendation is also for all square bales, heavy chopped bales and those for livestock sensitive to mould – horses, sheep and pregnant animals.

6, Chose the bale wrap colour. Traditionally, black wrap is used however green and white are proven to keep bales cooler and promote better fermentation, another way to help reduce spoilage losses and improve silage quality.

7, Once wrapped, look after the bales by handling them with care, patching any holes or tears, and storing on a level base, preferably covering with a net to deter bird damage.

Making top quality big bale silage will significantly reduce grass silage dry matter losses this season reducing the feed bill later on.


  Related Links
link Control Weeds to Maximise Silage Yields and Quality
link BCPC Launches New Congress in Brighton
link Faster Spreading Nitrogen Saves a Day

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