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

The production, absorption and pathways of utilisation of volatile fat ty acids (VFAs) by ruminants are reviewed. Acetate fulfils a central r ole in ruminant metabolism, which is interdependent upon other key nut rients such as other main VFAs, amino acids and glucose. The interacti on 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 t he energetic efficiency of utilisation of VFAs. While there is a multi tude of conflicting experimental results, it seems that under practica l circumstances, the ratio of acetate to propionate absorbed has littl e impact on the energetic efficiency of ruminant production.