Introduction
The knowledge of the chemical composition of forages, reflected in their nutritional value, allows the composition of balanced rations in all the nutrients.
The nutritional value represents the forage ability to satisfy the energy requirements and the nutrients of animals.
The nutritive value of a forage is expressed in energy, protein, minerals, vitamins.
The amount of energy can be expressed in kcal or kj gross energy, digestible energy, metabolizable energy, net energy or conventional units (milk forage units), expressed per kg of forage or kg of dry matter.
The best performing system for ruminants is based on net energy, because it takes into account all the energy losses that occur between ingestion and cell use. Based on net energy, it is calculated the milk forage unit (UFL) which represents the net energy value of one kg of barley, used as reference forage, distributed to dairy cows.
