Blue chicory flower
The pastures and forage crops discussed here are the major sources of parent material likely to be conserved as silage.
As producers develop greater interest and experience with silage, they are likely to use a wider range of crops, e.g. forage brassicas and chicory.
Unfortunately, there is very little experimental data or experience in ensiling these less commonly grown crops. In the absence of clear guidelines, assume that non-‘grass’ crops may have a high buffering capacity and low Water Soluble Carbohydrate (WSC) content, and may be difficult to ensile.
They should be treated as for legumes – wilting is essential.
The crops discussed are those grown specifically for grazing, for forage production or both. Silage cutting is often integrated with grazing to improve the utilisation of surplus growth.
Silage is produced in a wide variety of climates in Australia, so specific management strategies have not been included. Local information is needed on varieties, fertilisers, irrigation management, and weed and pest management.
Seedbeds left uneven or cloddy after sowing may need rolling, before plant emergence, to prevent soil contamination of the forage at harvest. As well as creating wear problems with equipment, soil contamination can also introduce undesirable bacteria, which may affect silage fermentation.
The Key Issues
- The most cost-effective production of silage is when there is a genuine excess of forage that cannot be grazed.
- The silage’s nutritive value varies with the species and variety conserved, and the growth stage at which it is cut.
- Attention to good agronomic management is essential to achieve high forage yields of high nutritive value.
- Both feed quality and quantity are important in determining the profitability of animal production from silage. Silage quality places a limit on the potential animal production per tonne of silage DM. Production of low-quality silage is likely to be unprofitable.
- Monitor soil fertility using soil tests and ensure long-term soil fertility is maintained by replacing nutrients removed in silage.
- Read all labels on pesticides and chemicals used on silage parent forage to ensure they are used correctly and stock withholding periods are satisfied.
- A comparison of pastures and forage crops suitable for silage production
Silage is often only made from pastures or forage crops when growth is surplus to the animals’ requirements. A feed budgeting approach can be used to estimate the quantity of surplus forage likely to be available for conservation.
The cost of growing these pasture and forage crops should only be considered in a budget for silage when inputs have been increased specifically for silage production, e.g. higher fertiliser rates or increased irrigations. There are also potential pasture management and weed control benefits that can be attributed to silage which should be taken into account
Table 4.1 summarises characteristics of pastures and forage crops commonly grown for silage production, emphasising the forage management strategies required to optimise silage quality. There is a huge range in the quality of silages being produced. The large range suggests many producers are losing production potential because of poor silage-making practices.
Factors affecting the yield and feed quality of silage The principles discussed in this section apply to most of the crops and pastures used as silage parent forage. Later sections in this chapter and in Chapter 5 contain more specific information relevant to the crops and pastures most likely to be used for silage production.
