Abstract
Published data for a wide variety of foods given to sheep were analysed statistically in order to clarify the relationship between metabolizable and digestible energy. Metabolizable energy was not a constant fraction of digestible energy; values ranged from 70 to 85%, depending on level of feeding and digestibility. A linear equation described the relationship for most diets and all levels of feeding. A possible reason for differences between diets is mentioned. The equation is shown to be valid for cattle.