Important steps to achieving mould and yeast-free silage

All baled silage needs to be free of visible growth of mould/yeast. This means that the air-free seal that is needed to permit good preservation must be fully maintained through to feedout. Important steps to achieve air-free conditions include: • Good wilting (i.e. drying) for 1 day can help produce bales that will be better at retaining their shape. The target is to reach 30% dry matter. This was discussed above. • Make very firm, regular-shaped bales. This involves producing evenshaped windrows and using a relatively slow forward speed for the baler. Engaging sharp cutting blades in a baler should increase bale density by about 10% (i.e. bales will weigh 550 rather than 500 kg), thereby making them firmer. When allied to properly wilted grass these bales are likely to retain their shape during storage, thereby helping maintain the integrity of the plastic seal. • Uniformly apply not less than 4 layers of film. Four layers of conventional film are necessary and, if applied properly, are adequate in most circumstances. Six or more layers of film are occasionally used where confidently producing a visibly mould-free bale of silage is particularly important. Under Irish climatic conditions the colour of the plastic film does not have a direct effect on baled silage quality – thus, black, green and white films can be equally effective. • Ideally transport the bales to the storage area and then wrap them. In many cases it can be difficult to transport a wrapped bale weighing 400-600 kg without causing some mechanical damage to the plastic film. This risk can be greatly reduced by transporting the bales to the storage area and then wrapping them. However, this is often not practical. • Move field wrapped bales to storage area immediately. The reasons are that this reduces the risk of wrapped bales being attacked by birds in the field; the bales are moved while their shape is more perfectly cylindrical (thereby reducing mechanical damage), andthe freshly applied plastic film can more effectively adapt to the mechanical strains applied during handling.