In the UK the majority of dairy cow diets are based on grass silage and tend to over supply effective rumen degradable protein (ERDP ) as defined by the Metabolisable Protein (MP) system. As a result the nutritionist is often required to make up a shortfall in digestible undegraded protein (DUP) supply, particularly in diets for high yielding cows. Sources of additional dietary DUP fall into two categories: - vegetable or animal in origin. The DUP content of fishmeal is significantly higher than any of the naturally occurring vegetable proteins and the industry has been searching for some time for ways of improving the DUP content of vegetable proteins.

In a novel treatment process soyabean meal is incubated at low temperature overnight in a solution of lignosulphonate. The treated meal undergoes a maillard reaction which reduces the extent of degradability in the rumen but does not affect digestibility in the small intestine.