Ten tips for making good quality baled silage

Ten tips for making good quality baled silage

Padraig O'Kiely and Dermot Forristal

Teagasc, Grange & Oak Park Research Centres

[Article for Irish Farmers Journal, April 2003]

1. Plan

Baled silage is now quite expensive to make, so it is important that the money a farmer invests in producing a meadow and in then mowing, baling, wrapping and storing it are adequately repaid. The chances of success are much higher where the major issues can be pre-planned rather than where making baled silage becomes a rushed or salvage operation. Thus, it is important to work out in advance

- how much baled silage is required and which fields it should come from

- approximately when it should be harvested

- how (or by whom) will it be mown, baled/wrapped and transported

- where it will be stored

- where and when it will be fed.

Wilting is an important component of making baled silage, so some flexibility is needed in the plan to ensure the meadow can be mown when weather conditions permit good field drying.

Baled silage differs from conventional clamp silage in that most of the costs – baling, wrapping and transport- are incurred on a per-bale (effectively per-tonne) basis. Consequently there is a lesser penalty for cutting high-quality, low-yielding, grass crops. This feature can be exploited on farms, and encourages conserving good quality grass, where the superior feeding value of a highly digestible bale more easily justifies its ensiling cost.

Finally, always incorporate the need for on-farm safety in all aspects of making, storing and feeding bales.

2. Mowing

- manage mowing to promote effective wilting

- mow a meadow after the dew has evaporated. This is because a heavy dew on a high-yielding meadow contributes over three tonnes water per hectare (over 1 tonne/acre) and surface water usually dries quicker from a standing crop

- monitor weather forecasts, and try to mow and wilt during a spell of dry, sunny weather.

3. Wilting

The radiant heat from direct sunshine together with the dryness of the air are what evaporate water from a wilting crop. Thus, the more of a mown meadow that is exposed to sunshine and air movement the better.

- the target is to bale the grass at about 30 to 35% dry matter (DM)

- aim that the mown swath is on the ground for preferably one, and at most two, nights

- the grass treatment required to achieve this will depend on the yield of the crop and drying conditions - heavy crops in moderate drying conditions will require the most aggressive approach

- if a mower-conditioner is used, ensure that the gates behind the conditioner are opened so as to leave the grass in a wide swath. Aim for 60 to 80% ground cover.

- if available, use of spreader-mowers, which give up to 100% ground cover, can eliminate the need for separate tedding in certain conditions

- if it is planned to tedd grass, do it as soon as feasible after mowing so as to maximise the duration that most grass is exposed to sunshine. If there is a risk of rain overnight, or if baling is expected to be carried out early the following morning, it may be advisable to windrow the tedded grass before nightfall.

- minimise the production of lumpy swaths.

- manage wilting with the aim of helping to subsequently facilitate making firm, regular-shaped bales

4. Baling

Aim to make dense, well-shaped bales. These bales will be heavy. However, the reduced number of bales per hectare decreases baling, wrapping and transport costs. Well-shaped bales are easier to wrap properly and to handle without causing damage.

- aim to present well-shaped swaths that suit the baler pick-up

- adjust the baler density setting to the maximum allowable position

- drive the tractor to provide an even and balanced flow of grass into the bale chamber

- use a slow rather than a fast forward tractor speed, to help produce dense, well-packed bales

- balers with fixed knife choppers can fit an additional 8-15% more grass into a bale, depending on factors such as the number and sharpness of knives and grass type. Thus a bale that would have weighed 500 kg should weigh 540 to 575 kg if chopper knives were fitted. Choppers are only effective if the knives are sharpened regularly.

- additives should not be required where effective wilting and appropriate sealing are achieved

5. Wrapping

The simple but vital aim is to create oxygen-free conditions for the wrapped bale, and these conditions need to last through to feedout. When wrapped in 4 layers of conventional polythene (plastic) film, the thickness of such plastic on a silage bale is 70 μm compared to 250 μm for a double-sheeted silage clamp. With the new thin film on the market, it is even less. Since each bale of silage typically has 6 to 8 times the surface area in contact with plastic compared to clamp silage, it is clearly important that the plastic film is of good quality, is properly applied and is not subsequently damaged.

Bale wrappers are geared to apply film so that each layer overlaps the underlying layer by 50%. In Ireland , four layers of film are typically used, although in countries such as Sweden six layers are the norm. The number of revolutions of the wrapper turntable needed to ensure a nominal covering by 4 layers of film (750 mm) on a regular, well-shaped bale is about 16 turns. Experiments at both Grange and Oak Park have shown that a minimum of 4 layers of conventionally applied standard stretch film is required to conserve baled silage adequately. Where good management practice prevails, the benefits accruing from progressing to 6 layers of film are small (Table 1). However, where bales may be stored for a prolonged duration, 6 layers may be advisable. The production of dense, high dry matter (DM) bales from highly digestible grass, with in excess of 200 kg DM per bale, can justify the use of 6 layers of film. An increase of 25 kg DM per bale will pay for two extra layers of film by reducing the number of bales to be baled, wrapped, transported and stored.

- ideally transport bales to the final storage area and wrap them there. This avoids damage to the plastic wrap in the field caused by birds and reduces the risk of mechanical damage to the plastic during transport.

- count the number of wrapper turntable revolutions to ensure enough plastic film is applied

- ensure bale-drop table is working effectively to prevent damage as the newly wrapped bale is dropped onto the ground

- plastic film should be purchased from reputable sources only, and wrapping should be done in accordance with the wrapper and plastic manufacturers recommendations.

- ensure that the correct stretch is being used - the new thin films require a lesser stretch

Table 1. Importance of having adequate plastic film on bales

	Number of layers of conventional plastic stretch-film
	2	4	6
Rotted surface area (%)	73.1	5.2	0.1
Rotted depth (cm)	48.0	3.1	0.6
Dry matter (%)	26.8	29.0	30.0
pH	6.2	4.6	4.4
DMD%	66.6	71.1	72.0
Lactic acid (% DM)	4.0	6.1	6.5
Ammonia-N (% N)	17.9	12.5	11.9

Source: Teagasc, Grange Research Centre

6. Handling & transport

Gentle handling of bales before and after wrapping is essential in order to maintain the shape of the bales and the integrity of the seal provided by the plastic film.

- avoid rough handling of unwrapped bales as this can mis-shape them, thereby rendering them more difficult to wrap perfectly (avoid using a spike if feasible)

- transport wrapped bales to the storage area immediately after wrapping, and certainly within 24 hours. An extended delay can allow the shape of some bales to settle, making them more difficult to mechanically lift without causing damage to the plastic film.

- examine handlers for damage/rough areas, and ensure that the operator uses the handler with great care

- immediately repair any damage to the plastic film

- considerable amount of damage to the plastic film caused by birds can take place in the field shortly after wrapping. If wrapped bales cannot be transported immediately to the storage area, relocating them temporarily from the silage stubble to an area of green grass will usually avoid bird damage.

7. Storage

- select an uncluttered storage site from which the bales can be conveniently and safely removed at feedout time

- chose a level, smooth and hard surface on which to store the bales

- if the bales were made from wet grass, store the wrapped bales on a concrete pad from which effluent can be securely collected

- bales stored at ground level can be positioned on their curved or flat sides

- successfully wilted bales can be stored up to 3 tiers high if suitable bale handling equipment is available (max of two high if in REPS). Once stored two or more tiers high, the bales should be on their curved side.

- unwilted bales should be stored at ground level

8. Protect and inspect

- fence off the stored bales from livestock, etc.

- ideally, stacks of wrapped bales should be protected at the sides and top with fine mesh netting or monofilament lines (0.5 m spacing). Aim to have about a 0.5 m gap between the netting and the bales.

- whereas painted markings on bales do not provide fully secure protection from bird damage, they can significantly reduce the scale of damage. Use white emulsion paint (not oil based) on black plastic. 'Eye' shaped designs are more effective than X or O designs (see Figure 1).

- cats are a frequent cause of damage to stored bales, but it is not so easy to prevent access by them to the bales

- take appropriate steps to reduce the risk of rodents

- inspect the bales regularly for any damage to the plastic film, and repair damage immediately

9. Feeding

- bales can be fed to cattle at any stage after wrapping

- aim to have bales consumed within two days of unwrapping

- physically remove and discard mouldy bales or parts of bales and do not offer to livestock. Wear an appropriate face-mask, etc., when handling mouldy forage, and adopt appropriate hygiene precautions afterwards.

10. Collect plastic

- collect the plastic wrap after removal from bales, and dispose of it in an environmentally benign manner

- the Farm Relief Services provide a free collection service for waste silage covers and round bale wraps - contact at freephone 1800 300 444. Terms and conditions apply.

Figure 1. White paint markings on bales: ‘X’, ‘O’ and ‘eye’.