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Green Acres Factsheet -Silage quality and concentrate supplementation

Grass silage is an important winter feed in calf-to-beef systems. Balancing this forage with the correct quantity/quality of concentrate is key to achieving desired winter weight gains. The Teagasc Green Acres Calf to Beef team has published a Fact Sheet on the silage quality and concentrates topic

Why complete a silage analysis?

  • Visual assessment alone is not adequate to determine silage quality; laboratory
    testing is recommended.
  • Provides information on silage nutritive value and preservation; informed
    concentrate feeding decisions can be made.
  • A breakdown of dry matter (DM), dry matter digestibility (DMD), metabolisable
    energy (ME), UFV, UFL, pH, crude protein and other relevant information will be
  • Mineral profiling (macro and trace) of silage can be obtained through a wet
    chemistry analysis.

Correct sampling procedure

  • Poorly taken silage samples often lead to inaccurate results.
  • A period of 5-6 weeks should elapse between ensiling and sampling.
  • A long core sampler should be used.
  • 3-5 cores from well-spaced points on or between diagonals on the pit surface
    should be sampled.
  • Core to within 0.5m of the pit floor.
  • Discard the top 5 inches of each core before mixing into a composite sample.
  • Alternatively sample an open pit by taking nine grab samples in a ‘W’ pattern
    across the pit face.
  • Exclude air, seal well in a bag and avoid posting samples late in the week.
  • When testing bales, a number of samples from each batch of bales made must be
    taken in order to get a representative sample. Test each batch separately.
  • Use only Forage Analysis Assurance Group (FAA) accredited labs when having silage samples analysed.

Winter weight gain requirements

Calf-to-beef systems require superior quality silage, as animals have to perform at every stage of the production system. Table 2 highlights the targeted average daily gains (ADG) of animals over the winter months for various production systems.

Matching silage quality and concentrate feeding

  • Concentrate supplementation provides energy and protein to an animal’s diet that may be lacking in silage.
  • Calf-to-beef systems require excellent quality silage (DMD of >72).
  • Additional meal supplementation will be required to improve the overall energy/protein density of the diet where silage quality is sub-optimal.
  • Growing and finishing animals have varying requirements for energy and protein – one concentrate will not do both.
  • Ensure animals are adequately provided with minerals, either through the concentrate or additional supplementation.
  • For more detailed information on balancing silage quality and concentrate feeding, contact your local Teagasc advisor.


Energy is typically the most limiting factor in beef diets. In terms of rations, weanling rations have a requirement of >0.94UFL, while >0.92UFV is necessary for finishing rations. Table 3 provides guideline daily concentrate feeding rates depending on the quality of silage (DMD) available.



After energy, protein is the next limiting factor in the winter diet of dairy-beef animals. Always balance the protein content of the concentrate with the protein content of silage. Weanling rations should have a crude protein content of 14-16%, while 11-14% is needed for finishing rations.


View factsheet here GreenAcres Silage Factsheet (PDF)

To find out more about the Green Acres Calf to Beef Programme click here https://www.teagasc.ie/animals/beef/demonstration-farms/green-acres-calf-to-beef/