Near-infrared spectrometry for the characterization of feed resources

The management of livestock systems for technical, economic and environmental optimization requires an increasingly accurate formulation of rations and therefore a detailed knowledge on the feeds consumed by animals. Near-infrared spectrometry (NIRS), which has been used increasingly since the 1960s, is an analytical technique that allows rapid characterization of feeds or forage samples. The first applications developed were on the chemical composition of the feeds, but it is also possible to develop calibrations for the estimation of the nutritional value and the feed intake. Beyond these direct measurements on the feed, NIRS can also be applied to faeces to characterize the feeding of animals on rangelands. Joint consideration of feed and feces spectra can give a picture of how animals actually use feeds. Other possible uses of NIRS such as traceability or feed classification and botanical recognition of plants in grasslands are also described. The current technical developments, and in particular the miniaturization of spectrometers, make it possible to bring the instruments on the field to produce information as close as possible to its use. Other spectroscopic techniques that are alternative or complementary to NIRS such as mid-infrared spectroscopy, Raman spectroscopy or hyperspectral imaging will allow other measurement conditions and other applications.