THE PRODUCTION AND METABOLISM OF VOLATILE FATTY-ACIDS BY RUMINANTS FED ROUGHAGES - A REVIEW

The production, absorption and pathways of utilisation of volatile fatty acids (VFAs) by ruminants are reviewed. Acetate fulfils a central role in ruminant metabolism, which is interdependent upon other key nutrients such as other main VFAs, amino acids and glucose. The interaction of these key nutrients has received little attention, particularly in roughage-fed ruminants. From theoretical considerations, the ratio of acetate to propionate absorbed into circulation appears to affect the energetic efficiency of utilisation of VFAs. While there is a multitude of conflicting experimental results, it seems that under practical circumstances, the ratio of acetate to propionate absorbed has little impact on the energetic efficiency of ruminant production.