Abstract
Fiber plays an important role to maintain the normal functioning of the rumen in cattle fed with high-concentrate diets. However, the optimal incorporation of fiber in the finishing diets should counteract the two main limitations of this ingredient in fattening due to the limitation in the ingestion of the diet and the dilution of diet energy as result to its low energy content. Therefore, efforts have been made to determine the optimal level of NDF in the finishing diets where the negative associative effects of the NDF are avoided without undermining its role as a functional feed in fattening. For the above, eight lambs (30.50± 4.44 kg initial weight) were used in a replicated 4 × 4 Latin square design in order to evaluate effective neutral detergent fiber (eNDF) levels (4, 8, 12, and 16% diet DM) on growing-finishing diets in lambs. Experiment had 4 period of 21 days each (17-d to diet adaptation and 4-d to sampling). Dietary treatments consisted of a cracked corn-based diet in which the eNDF concentration of diet was manipulated by replacing cracked corn grain by corn stubble. As the level of eNDF increased, intake of DM, MO, NDF, and GE were linearly increased (P < 0.01), but starch intake was decreased. The apparent digestible energy (Mcal/kg) showed a quadratic effect (P < 0.01) being maximal at 8% eNDF level increased. Ruminal pH increased (P < 0.01) from 5.77 to 6.70 as the level of eNDF increased. It is concluded that 4% of eNDF level in corn-cracked based finishing diet is enough so as not affect ruminal health in lambs. Digestible energy was optimized at 8% of eNDF level.