hY investigated the dfed of rumen pH on nuninal dry matter degradation rate ut SyS.a mples of alfalfa were incubated in the rumen of four Holstein steers (3tI[klS Edy weight) with ruminal fistula. Animals were fed wi~h diets diering in $hste:alfalfa ratios as W40 (TI), 70:30 (I?80:2)0 ,(T 3) and 90:10 (T4) in a 4 t i l l 01-d (2 mm) mnpk (5 g DM)w ere ~ c c idn a rtificial si* bags (~m?o pore size) and incubated in the rumen for 0.0, 2, 4, 8, 16, 24, 48, 72 and 96 h degradation beyond the lag-time were further adjusted to a negaiivc p=atb(l-e.-ct), where P= fraction degraded in the time t. a= rapidl) @tk fmction,-b slowly degradable fraction, c= fraclional degradation rate and 1= $on time]. Minimum daily ruminal pH decreased from 6.40 (TI) to 5.34 (T4) *hen fl Eoncentrate was increased. There was no significant difference when ruminat Ar! \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'&gradation parameters of alfalfa were considered.

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