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In situ dry matter, crude protein, and neutral detergent fiber degradability of some grasses in continuous grazing

The degradation kinetics, effective degradability (ED) of dry matter (DM), neutral detergent fiber (NDF), and crude protein (CP) with or without correction for microbial protein were evaluated from black oat, Mombaça, star grass and millet, taken from pastures at a continuous grazing. The forage was collected from different points of pasture every 14 days for black oat and every 28 days for the other grasses. The feeds were incubated in the rumen using nylon bag at different times (0, 6, 12, 24, 48, 72 and 96 h). Three bulls of 350 kg BW were used. For correction of microbial protein contamination in incubation residue the neutral detergent insoluble protein analyses were performed. For DM, black oat and millet had higher soluble fraction (a = 32 and 24%) and higher ED at 5%/h (53 and 48%). The winter stargrass presented the lowest soluble fraction (14%) and the lowest DM ED at 5%/h (23%). For corrected CP, black oat and millet had higher ED (80 and 75%) than the other grasses (average ED of 67%). The degradation rate and ED of CP were underestimated when the correction for microbial contamination was not done. For NDF, black oat presented higher ED at 5%/h (40%) followed by millet (35%), star grass-summer (23%), star grass-winter (19%) and Mombaça (16%). Black oat and millet showed higher soluble fraction, higher degradation and higher ED of DM, CP and NDF when compared to stargrass and Mombaçagrass.

black oat; degradability; millet; Mombaça; stargrass


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