Indicators of Feeding Value

Metabolisable energy (ME)(MJ/kg DM)

• Metabolisable energy estimates the amount of energy silage will provide the ruminant for production as well as maintenance.

• It is influenced more by the quality of grass at harvesting rather than efficiency of fermentation.

• Good silage is expected to have a ME between 11 - 12 MJ/ kg DM.

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Crude protein (CP) (% or g/kg DM)

• In silages, CP is mainly in the form of degradable protein which will be used by rumen microbes.

• High protein levels will indicate high level of nitrogen in the harvested grass, usually due to late fertiliser applications.

• This will have negative effects on fermentation.

• Good quality grass silage will have an average CP values ranging from 12 - 16%.

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Neutral detergent fibre (NDF)(% or g/kg DM)

• NDF measures the fibre or plant cell wall material in the silage.

• Fibre in the silage influences the rate of digestion by the animal and thus the level of intake.

• The higher the NDF, the lower the intake.

• It is important to supply the animals with long fibre (more than 1 cm) in order to keep rumen functioning correctly.

• There needs to be a balance between digestibility and sufficient fibre supply.

• Good silage will have 45 - 50% NDF.

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Potential intake

• Most analysis will give a rough estimation of intake based on fermentation characteristics as well as feed value of sample.​

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Maize and fermented wholecrop silage

• In general, maize and fermented wholecrop silage varies widely. Hence, it is important to analyse them before adding them to the cow's diet.

• Good indicator for maize silage quality is starch content between 25 - 35%.

• For fermented wholecrop, DM of 35 - 45% is important to have 15 - 25% starch.

• If starch levels are too high for maize and fermented wholecrop, it is crucial to formulate the diets to prevent acidosis.