The Effect of Various Levels of Dietary Protein upon the Volatile Fatty Acids in the Rumen of the Dairy Cow

Abstract

Total volatile fatty acids and the total amounts of propionic, butyric and valeric acids present in rumen fluid were increased with increasing amounts of protein in the ration. The proportion of acetic acid was significantly reduced while the proportion of butyric acid was increased with increasing levels of protein. Inability to accurately evaluate the effects of absorption and metabolism of these acids by the rumen makes quantitative conclusions difficult. It appears, however, that protein may serve as a source of volatile fatty acids in the rumen.