Variation in pH, volatile fatty acid concentration and proportions of the individual acids within the rumen of the dairy cow : a thesis ... M. Agr. Sc.

Abstract

An increased interest in rumen physiology and metabolism has resulted in the accumulation of a mass of data on the subject over the last two decades but information, particularly on quantitative aspects, is far from complete. It is now well established that the main non-nitrogenous end- products of rumen fermentation, the volatile fatty acids (VFA) acetic, propionic and butyric play a major part in the energy metabolism of the ruminant. They provide the major energy source for the animal and the amounts and proportions of the acids absorbed influence the efficiency with which the diet is used for fattening and can affect the milk composition of the lactating cow. Thus a knowledge of the type of fermentation produced is necessary, as a contribution to the assessment of the nutritive value of feedstuffs and the efficiency with which they are converted to animal products. The results obtained by different investigators are seldom strictly comparable as the pattern of rumen fermentation and the concentration and proportions of the VFA s may be considerably modified by factors other than the composition of the diet. Such factors are the level of intake, the feeding regime and sampling techniques adopted. [From Introduction]