Abstract
A study was made of the effect of two feeding systems on the variation of pH and volatile fatty acid (VFA) concentration within the reticule-rumen of one cow. VFA concentration and pH were determined on samples of ingesta removed from five positions within the reticule-rumen. With both feeding systems the ingesta in the dorsal region of the rumen was higher in VFA concentration and lower in pH than the ingesta in the ventral region. The magnitudes of the differences were dependent on the sampling time during the day and on the day itself. The relative proportions of the individual acids did not vary with the sampling position. It was concluded that the most suitable representative sample was either one from the centre of the ingesta or a composite one from the dorsal, central, and ventral regions.