Aunir Glossary - Energy

NIR technology is capable of estimating the energy content or bio-available energy to animals based on the chemical composition of the feed. There are many energy calibrations available in the market place but AusScan Online is unique in being based on in vivo data.

But what is energy? And what does it mean?

There are a number of measures of energy related to animal feeding, with use often depending on personal experience or preference.

To start, energy is measured in either Calories (Cal) or Joules (J), and the total energy in the sample (which can be released for example by combustion) is known as the gross energy (GE) content.

When feed is ingested by an animal, the undigested fraction is excreted in the faeces, with the difference between gross energy and faecal energy defined as digestible energy (DE or faecal DE).

Subtracting the urinary and gaseous energy from the DE gives the metabolisable energy (ME) which is the best estimate of the energy available to the animal.

And a further subtraction of the heat increment associated with the feed leaves net energy (NE). This NE can then be used by the animal for either maintenance (e.g. maintaining metabolic functions) or production (growth, egg or milk production etc). 

Here is a diagram showing the different measures of energy and how they relate to each other.