The objective of this experiment was evaluate the ruminal degradation kinects and effective degradability (ED) of dry matter (DM) and crude protein (CP) of four experimental diets, with different substitution levels (0, 20, 40 and 60%) of corn silage by pineapple by-products silage. It was evaluated pineapple by-products silage individually. Three bulls (½ Nelore x ½ Angus) with ruminal cannulas and average weight of 350 kg were used. The samples of each diet and of pineapple by-products silage were mixed and grounded through a 5 mm screen grinder. The feed were incubated in the rumen using nylon bag in times 4, 8, 12, 24, 48, 72, and 96 hours. The pineapple by-products silage when incubated individually presented the values of 28.8%; 49.4%, and 4.2%/h for the parameters a, b, and c of DM and 55.9%; 34.6%, and 5.5%/h for CP. The pineapple by-product silage presented values of 51.4% and 74.1%, respectively for ED of DM and CP at passage rate of 5%/h. With different substitution levels of corn silage by pineapple by-products silage, the fraction a the DM presented a quadratic negative behavior and the fraction b a quadratic positive behavior. The c parameter presented a quadratic positive behavior with maximum value in T40. For CP, the parameters a presented a linear positive behavior and the parameter c, a linear negative behavior. The fraction b presented a quadratic positive behavior. At passage rate of 5%/h, the ED of DM presented values of 53.0%; 51.9%; 55.2% and 50.9%, and the ED of CP were 70.7%; 70.5%; 66.8%, and 72.7%, for the substitution levels of 0, 20, 40, and 60% of corn silage by pineapple by-products silage.
cattle; corn silage; degradability; feedlot; pineapple by-product silage
