The objective of this work was to evaluate the ruminal degradation and intestinal and total dry matter (DM) and crude protein (CP) digestibility of soybean meal, corn grain, dry molasses, fish meal, feather meal and alfalfa hay, by the in situ degradability technique associated to the mobile nylon bag technique. The samples of the feeds were milled and put in nylon bag of 10x5 cm (48 micras) in the amounts of 15 and 5 mg of DM/cm² for concentrate feeds and alfalfa hay, respectively. The nylon bags were incubated in the rumen of Holstein steers during 0; 2; 6; 8; 24 and 48 h; and 0; 8; 12; 24; 48; 72 and 96 hours, respectively, and later were removed and inserted into the duodenum through a stem. The bags were collected with the feces. The values of effective degradability of CP for a rate of passage of 5%/hour for the dry molasses, corn grain, soybean meal, fish meal, feather meal and alfalfa hay, were of 100.00, 62.50, 57.90, 39.30, 34.20 and 60.90%, respectively; and intestinal digestibility of 100.00, 96.05, 99.79, 98.19, 96.07 and 94.64%, respectively; and total digestibility of 100.00, 97.86, 99.87, 98.88, 97.35 and 98.09%, respectively.The proteins of the molasses were totally soluble at the rumen; and the corn, alfalfa hay and soybean meal were quite degraded, besides they have good total digestibility in the intestine. The proteins of the fish meal and feather meal have low ruminal degradability and high intestinal digestibility, and the fish meal is digested more slightly in the intestine than the feather meal.
digestion; fermentation; rumen; ruminant
