Front end loader
Tractors with hydraulically powered front-end loaders are commonly used to empty pits/bunkers.
Attachments vary in complexity from a fork with a set of horizontal tynes that are forced into the heap and raised to tear out the silage, through to loaders with some form of cutting mechanism (e.g. shear grab or block cutter).
Front-end loaders fitted with a fork or bucket tend to leave a disturbed silage face, and require careful operation to minimise air penetration.
Table 10.2 gives the results of a comparison of alternative equipment for removing a lucerne/pasture silage (30-150 mm chop length) from a silage pit with face dimensions of 12 m wide by 2.5 m high.
This study confirmed that estimated losses were lower with the equipment that cut silage from the face, and left it relatively undisturbed.
Further studies, covering a range of silages and weather conditions, are required to more accurately quantify losses for various silage removal methods.
Tractor-mounted shear grabs and block cutters are efficient implements for removing silage and leave a relatively undisturbed face.
Shear grabs are the cheaper option and provide satisfactory work rates, influenced by the grab’s capacity and the distance from the stack to the feeding site (see Figure 10.3).
Block cutters can be front- or rear-mounted. They have a set of tynes that are driven into the silage and knives, either reciprocating or on a continuous chain, cut vertically down the surface removing a block of silage.
The weight of the block removed varies from 300 to 1000 kg, depending on the type of machine used. Some block cutters have guards to prevent the silage from spilling in transit, while others have clamps that hold the block firmly to the tynes.
Because the blocks are, in effect, an undisturbed part of the stack, air penetration is minimal and the block tends to remain aerobically stable well into feed-out.
More sophisticated pit/bunker unloaders, with rotating cutters, are available for operations that handle large quantities of silage. The silage is transferred into a wagon or truck for feed-out.
A rotating drum cutter is a common design, which has a rotating drum, about 30 cm in diameter, fitted with small knives. The drum is carried on a boom attached to a tractor.
The drum can swing in an arc up and down the face, the silage falls onto a conveyor belt and is delivered into a wagon or truck. This type of unit shaves the silage off the face, leaving it relatively undisturbed.
Care must be taken to ensure the unloader is moved sideways regularly so the silage face does not become irregular.
The Australian market for silage-handling equipment is expanding rapidly as the amount of silage produced increases.
Producers intending to buy equipment should seek information on the machinery that is available, and the work rates of various machines, from machinery dealers.
Any capital investment in equipment and facilities should be based on sound business principles, i.e. careful consideration of the costs and benefits.
