[In situ digestibility of alfalfa hay and maize silage under two ruminal conditions, induced by feeding]
1993
Robert O, Marcelo Fernando
Four rumen fistulated dairy cows were used to study the in situ digestibility of alfalfa hay (AH) and corn silage (CS). Animals received two diets; high and low concentrate supplementation to produce two ruminal environments. Cows were rotated in the two diets for 21 days as an accustom phase. 5 g each of AH and CS were incubated in nylon bags of 15x9 cm of 1600 holes/cm2 during 2, 4, 8, 12, 24, 36 and 48 h. Contents of dry matter (DM), protein (CP), acid detergent fiber (ADF), lignin and ash were determined for each sample. Data were analyzed in a factorial arrangement to observe effects of factors (ruminal environments, incubation time, animal, food and replication) and their interactions. Ruminal pH was lower (P0,05) in diets with high level of concentrate. The disappearance of food components was not significant between the environments with high or low concentrate supplementation. Dynamics of digestion of forages is different between AH and CS. Potentials of digestion for AH and CS were: 70,2 and 68,8 for DM; 82,8 and 71,4 for CP; 47,7 and 48,7 for ADF; 18,8 and 30 for lignin; 83,4 and 54,7 for ash, respectively
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