Contributed to: Proceedings of the British Society of Animal Science 2001, p.133. (York, Reino Unido, April 9-11, 2001)Non-additivity occurs when the nutritive value of a mixture of feedstuffs differs from that of the sum of
its components. It is most commonly observed when one dietary constituent influences, either positively or negatively,
the apparent digestibility of another under conditions where components such as nitrogen and sulphur are non-limiting.
In general negative effects occur due to the depression of rumen pH or substrate competition, while positive effects
have been identified when readily fermentable fibre sources such as sugar beet pulp have been included in rations
containing poorly fermented forages such as cereal straw. With the increasing use of in vitro systems, not just to
examine feed degradation characteristics but to derive parameters such as microbial protein yield, the following study
was conducted to determine whether such interactions could be identified in vitro.Peer reviewe
