This study measured the kinetic parameters of the ruminal degradation of the silage of Brachiaria brizantha cv. Marandu. The experiment had a completely randomized design with five treatments and five repetitions; the treatments featured the inclusión of natural brewer&#8217;s grain to Marandu grass silage at levels of 0, 10, 20, 30 and 40%. The regression equation for the degradability of the soluble Fraction A of dry matter showed a linearly increasing pattern (P<0.05) with an addition of 0.19% for each 1% of brewer&#8217;s grain included. The percentage of insoluble potentially degradable fraction (B) of dry matter was reduced linearly (P<0.05). The ruminal degradation rate in the dry matter (c), expressed as % h-1, increased linearly (P<0.05). The crude protein percentage in the Fraction B demonstrated a linear regression pattern as brewer&#8217;s grains were added (P<0.05), and there was a 0.06% reduction per unit of additive to Marandu grass silage. There was a linear increase in degradation rate c in the crude protein (P<0.05) as the additive was included in the silage. A linear increase (P<0.05) was observed for the regression of the potentially degradable fraction of NDF, represented by Fraction D. The inclusion of 20% of brewer&#8217;s grain to Marandu grass silage resulted in an improvement in the kinetic parameters of ruminal degradation.