The effects ofprotein supplementation on degradability of dry mattter (DM), crude protein(CP) and neutral detergent fiber (NDF) and acid detergent fiber (ADF) were evaluatedin beef cattle grazing Brachiaria brizantha cv Marandu. It was used four Neloresteers (395 ± 9 kg) fitted with ruminal cannula to evaluate kineticsand degradability of the liquid phase and of the particles. Forage samples werecollected in other two steers with esophageal cannula. Supplements with 50,40, and 30% of crude protein (CP) were given at the proportion of 400 g/animal/daywhen compared to control suplementation with only salt and mineral. The offerof protein supplement did not change potential degradability of dry matter,crude protein and neutral detergent fiber but promoted an increase from 36.85%to 48.97% on effective degratability of dry matter and from 22.06% to 30.05%on neutral detergent fiber degradability. Supplements with 40 and 30% of crudeprotein were higher than the control because they promoted higher efffectivedegradability of crude protein and higher particle exit rates. The liquid passagerate was 11.4% higher for the animals which received supplementation when comparedto the control. The effective degradability of ADF was not affect by consumptionand it ranged from 12.19% (control) to 16.75% (supplement with 30% of crudeprotein). The results of this work show the importance of protein supplementationto animals on pasture of low quality and also the N level of the supplements.
