Rumen degradability of xylose-treated soybean meal determined with nylon bag Technique (in situ)

A ruminal in situ experiment using three ruminally fistulated multiparous non-lactating dairy cows was conducted to determine dry matter (DM) and crude protein (CP) degradation of soybean meal and xylose-treated soybean meal. Samples were suspended in the rumen of cows for 0, 2, 4, 8, 16, 24 and 48 h. Xylose-treated soybean meal had higher soluble digestible fraction (a) of DM than soybean meal (21% vs. 27%). Soluble digestible fraction (a) CP of xylose-treated soybean meal was considerably lower than that of soybean meal (3% vs. 20%). Xylose-treated soybean meal showed higher slowly digestible fraction (b) CP than soybean meal (84% vs. 78%). Effective degradability of CP at outflow rates of k= 0.05 and k= 0.08 h-1 was significantly lower for xylose-treated soybean meal than soybean meal (27 and 20% vs. 62 and 53%). Results from this study showed that xylose-treated soybean meal had lower available protein for rumen microorganisms compared with soybean meal.