Forage is an important locally produced protein source for dairy cows, but the utilization of forage protein in ruminants remains a challenging topic. A large part of the protein in ensiled forage is available in the form of free amino acids, ammonia and other simple nitrogen compounds as well as other rumen degradable protein(RDP). To capture the free amino acids and ammonia for microbial protein synthesis, instant energy sources, such as sugars, are needed, and for the other RDP, also digestible fibre is needed.

This is important as the majority of the metabolisable protein (MP) from forage, which is used for milk production and growth in the cow, originates from microbial protein in the rumen, whereas only a smaller part originates directly from the feed undegradable protein. As a result, the energy content of the forage is at least as important as its crude protein (CP) content. To increase the use of forage protein, thereby decreasing the need for protein from concentrates with imported soybean meal, attention is needed for several plant and management factors that affect both the content and quality of the forage CP.