Successful Silage – I
When To Wrap And Transport Baled Silage
Frank Mickan, Pasture and Fodder Conservation Specialist, DPI EllinbankMany farmers and contractors ask themselves ‘how long after baling can I delay wrapping without causing losses?’ and ‘when should I transport wrapped bales after baling?’
Wrap bales A.S.A.P.
Plant respiration (breathing) and proteolytic processes (protein breakdown) continue after mowing. Plant respiration continues in the bale while oxygen and plant sugars are present, thereby prolonging the drop in pH levels required, if wrapping the bales is delayed for too long. While the plants are still respiring, both energy and dry matter is being lost.
The sooner the bale is wrapped, the lesser the dry matter and nutritive losses will be. Bales should be wrapped within two to three hours of baling. If the inside of the bales are warming energy is being lost, which ultimately means that the value of the silage is declining, and money is being lost. Bales left unwrapped for several hours, especially if loosely baled, will be hot within hours. This will result in a lot of energy and value being lost.
Energy Loss = $$ Lost
Combined baler/wrappers (where the wrappers are behind the baler) and integrated baler/wrappers (where the baling chamber is also used for wrapping), are ideal in that bales are immediately wrapped after baling, thereby reducing losses in energy from long periods of exposure to oxygen. However, these wrapped bales must then be moved without damage to the plastic film. How to transport wrapped bales is discussed later in the article.
When forage is being baled by machinery separately to the wrapping process, they should ideally be transported to the storage site and then wrapped, or wrapped in the paddock within one or two hours in either case.
Transportation – when and how
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Figure 1: Silage bale grab |
Once bales are wrapped, some machinery representatives advocate shifting bales straight away before the plastic finally seals; while others recommend leaving the bales for several days to weeks, until they have ‘cooked’ or fermented. Who is correct?
There is very little research into when bales should be transported after wrapping. However, one Norwegian experiment offers some insights. Using a Vicon RF 130 Balepack, grass bales were produced at three different dry matter (DM) percentages: an immature (leafy) crop with 16.6 per cent DM; a more mature crop two weeks later at 24.5 per cent; and a similarly mature crop wilted one day to 45.0 per cent DM. As the 16.6 and 24.5 per cent DM crops are far wetter than what is recommended for Australian condition, the results are not included in this article.
All of the bales, except the control group, were wrapped with six layers of white plastic immediately after baling. Half of the wrapped bales remained in the paddock for four to five days before transportation, while the other half were transported 300 metres (a short distance in most Australian situations) immediately after wrapping to a storage site. Four different implements were used to transport the wrapped bales:
- Dalen silage bale grip 1591
- Kverneland Silagrip 7700 with lifting tubes fitted with two rollers
- Trailer, loaded and unloaded by the Kverneland Silagrip
- Bale fork with three tines (spikes), with the holes being immediately patched with bale tape.
The control and unwrapped bales were transported immediately after baling and were wrapped as above with a Kverneland Silawrap UN 7558 at the storage site.
Table 1 shows the effects of the different transportation equipment on the mould growth and wastage of the wilted bales (45 per cent DM), when transported immediately after baling.
Table 1: Fungal growth and wastage of silage bales wilted one day and transported immediately after baling with different equipment
| Transport | Bale weight | Wasted | Surface Mould (% area covered) | |
|---|---|---|---|---|
| Equipment | (kg) | Silage (%) | Bale ends | Bale sides |
| Unwrapped | 646 | 0.1 | 0.3 | 0.3 |
| Bale Grip | 604 | 1.6 | 0.4 | 2.4 |
| Rollers | 659 | 0.9 | 0.5 | 2.3 |
| Trailer | 645 | 0.8 | 0.4 | 1.8 |
| Fork/Tines | 645 | 1.1 | 4.3 | 1.5 |
Source: Adapted from A.T. Randby and T. Fyhri (2005)
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Figure 2: Kverneland SilaGrip |
The transport of silage bales prior to wrapping resulted in bales with the least percentage of mould and wasted silage. Transportation using the rollers, and with the trailer loaded by the rollers, gave the most gentle handling of the wrapped bales. The bale grip machine damaged the plastic slightly more than when using rollers, as seen by the increased amount of wastage and mould growth (Table 1).
The results show that using the fork/tines was the most disruptive method, with mould in the bale ends higher and side moulding about average of all equipment types. To compound the problem, heavy rain and wind caused the patches to come off in time. The bales moulded least when transported from the paddock four to five days after wrapping.
For optimum quality, silage bales should be wrapped as soon after baling as possible to minimise energy losses and losses in nutritive value. When baling and then transporting the bales to the storage site, it is important to wrap the bales as soon as possible. If baling and wrapping in the paddock in the same operation, the bales should be transported within a few days. It is essential to check the condition of the plastic wrap and patch any holes immediately.
