Evaluation of the effects of synchronising the availability of N and energy on rumen function and production responses of dairy cows - a review

This paper reviews the effects of synchronising the availability of N and energy on rumen function and production responses of lactating dairy cows. The paper makes a key distinction between altering the synchronicity of diets by changing dietary ingredients, or by altering the feeding frequency or the feeding patterns. Manipulating synchrony by changing dietary ingredients presents some problems, since it is not possible to discount the possibility that apparent effects of synchrony are associated with the manipulation of the ingredients (level and type) themselves. These problems can be overcome, at least partially, by altering the feeding patterns. This review shows that the evidence for the benefits of synchronising energy and N supply to the rumen is contradictory, both for efficient microbial protein synthesis and for maximising milk production responses.