What is dietary metabolisable energy?

Abstract

Metabolisable energy (ME) is frequently used as the sole indicator of forage quality by researchers, rural professionals and farmers, but it is hardly ever measured and is not always a good predictor of feeding value. Forage ME is usually calculated from chemical composition and digestibility, often by near infrared reflectance spectroscopy (NIRS). Although ME is superior to dry matter (DM) as a measure of feeding value and can indicate forage quality, it should not be used to predict animal production. The ME content of DM may imply a potential for production, but other components of the diet, especially protein, structural fibre and feed availability will provide more information than ME alone. Researchers, rural professionals and farmers should understand the basis for measuring ME, exercise discretion when using ME, and include fibre and protein concentrations in their criteria for feed appraisal. Keywords: metabolisable energy, forage quality, feeding value