FAA Test Methods

How is forage analysed?

Measuring the nutritional quality of silage is not a simple task. It is by nature, a variable material. There are many factors to take into account when analysing it, including the type of silage, how to take a representative sample from a clamp or bale, what nutrients should be measured, what method to use and how quickly the answer is needed.

The FAA Group’s role is to reduce this variability. It achieves this through instrument standardisation protocols, the monitoring of routine procedures, the sharing of information and specific quality control checks such as the Proficiency Test Scheme..

Nutritional analysis has traditionally been completed in a laboratory using well-established techniques involving glassware and reagents. Known as wet chemistry, this gives the most accurate results. However, it can still be affected by poor sampling techniques and takes longer to carry out.

With the requirement for ever faster answers and the development of understanding how nutrition and diet directly affect animal welfare and productivity, the technique of Near Infrared Reflectance Spectroscopy (NIRS) was developed for nutritional analysis.

This technique scans a silage sample and using a series of calibrations, produces a set of nutrient values for that sample. This method is described as wet or fresh NIRS.

Some laboratories dry and grind the silage samples before carrying out a NIRS scan. This helps to reduce any variability seen by the instrument, but still relies on a representative sample being taken.

NIRS instruments are used in laboratories and handheld units can also be used on farm. NIRS can produce accurate results, but it is worth remembering that an instrument can only scan what it sees and if it has not been set up correctly or the sample if poorly mixed, then the results may not be reliable.

FAA Group member laboratories can be relied upon to carry out the best possible analysis on your forage. Make sure you discuss with your laboratory or adviser to understand the methods and results being used to achieve the level of accuracy for your needs.

See our FAQ page for some common questions that can arise.


A Wet Chemistry Lab

Example Machine Results Screen

Sample Lab Report


Our Contact Details

Forage Analysis Assurance Group
First Floor, Unit 4 The Forum
Minerva Business Park, Lynch Wood
Peterborough, Cambridgeshire, PE2 6FT
+44 (0)1733-385230

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