[Displacement of the bovine abomasum: effect of the diet on the composition of the rumen fluid and that of the contents of the abomasum and duodenum (author's transl)].

High-concentrate diets apparently inhibit abomasal motility by increasing the amount of volatile fatty acids (VFFA) which enter the abomasum. This report is concerned with a study of cows fitted with ruminal, abomasal and duodenal cannulae after feeding hay ad lib. and a diet consisting of hay and concentrates. Ruminal, abomasal and duodenal samples were analyzed before and after feeding. It was shown that a considerable increase in ruminal VFFA concentrations was not followed by a subsequent increase in abomasal VFFA concentrations. Differences in abomasal VFFA levels between the two rations were not observed. The VFFA concentrations in the duodenal fluid continued to be low and did not attain levels capable of affecting abomasal motility. The changes in pH level and in the sodium, potassium and chloride concentrations after feeding were also recorded. There were significant differences in the electrolyte concentrations of the ruminal, abomasal and duodenal contents between the rations before and after feeding. Part of these differences could be accounted for by findings reported in the literature.