Determination of buffering capacity of selected fermented feedstuffs and the effect of dietary acid-base status on ruminal fluid pH

Abstract

The aim of this study was to evaluate the buffering capacity of some fermented feedstuffs and the effect of dietary acid-base status on ruminal fluid pH. The first experiment was performed with different types (n = 24) of wet and dry fermented feedstuffs to determine the buffering capacity and buffer value index. The buffer value index of wet corn silages was more negative than for dry corn silages account on acid loss during drying. In the second experiment, the effects of different concentrations of lactic acid on base-buffering capacity, buffer value index and indicators of fermentation process were studied in two groups of corn silages (n = 21). Two groups of analyzed values were compared using unpaired t-test. Differences among the groups in base-buffering capacity (P < 0.001) and buffer value index (P < 0.01) were significant. In the third experiment, rumen fluid pH was measured using 8 total mixed rations on 48 lactating dairy cows. In the present study no significant (P > 0.05) correlation was found between ruminal pH and dietary buffer value index. These results confirmed that dietary acid-base status alone is not adequate as a predictor of the need for buffers in the diet of lactating cows. It is the first report about using of buffering capacity determination methods for evaluation of feedstuffs and dietary acid-base status in dairy cows.