Winter dairying

Regularly analyse silage to get maximum benefit

FARMERS are advised to pay close attention to how they sample silage clamps.

Dr Jonathan Blake, technical secretary of the Forage Analysis Assurance (FAA) Group, says it is also important to look at how often these analyses are carried out in order to derive maximum value from forages this winter.

The FAA is the quality control governing body for laboratories analysing wet forages.

“Dairy performance is very variable this winter and a big factor on many farms is silage quality,” says Dr Blake. 

“Forages are very variable with a wide range of nutrient analysis.  For example, data shows ME levels ranging from 8.8-12.7MJ/kgDM. That difference of almost 4MJ is enough to produce almost an extra litre of milk for every kilo of dry matter fed and shows the importance of getting a reliable assessment of silage feed value.


“Failing to have regular analysis can lead to three possible problems. Under-estimating silage values can lead to more purchased feed being used than is necessary which drives down margins.

“Over-estimating silage quality can lead to cows being underfed, which can have severe consequences for cow condition, milk yield and fertility.

“Finally a failure to complement forages correctly can lead to problems with rumen health and possibly acidosis.”

Dr Blake says time taken to collect a sample and react to the results is a small price to pay when compared to the potential benefits but the analysis is only as representative as the sample.

“Make sure you send the laboratory a representative sample and mix the handfuls together thoroughly on a clean surface to avoid contamination.”

Correct sampling methods

  • Work in a ‘w’ pattern across the face of the clamp
  • Take samples from 15-23cm (6 - 9”) behind the face
  • Take a total of nine to 15 samples ensuring each sample is taken from a different horizontal and vertical position
  • Avoid mouldy patches if they are not fed to the animals
  • Ideally clamps should be analysed at least every month
  • Detailed instructions on how to sample clamps can be found here

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