The objective of this research was to evaluate the effect of two grazing pressures on the availability of Brachiaria Decumbens forage. The research was carried out at the Quilichao Experimental Substation, of the International Center for Tropical Agriculture (CIAT), Cauca, Colombia. Eight initial availabilities of 4 300, 4 400, 4 800, 4 900, 6 000, 7 200, 17 400 and 18 900 kg of MSV per hectare were evaluated two initial grazing pressures: low, 1000 PV / 100 kg MSV and high, 1500 kg PV / 100 kg MSV. The design was of random blocks, with four replicas. The area was divided into 12 subplots per treatment and forage availability was measured at the beginning, at 2, 4, 6, 22, 26, 30, 46, 54, 70, 74 and 96 h of grazing. Commercial bullocks of the zebu race were used, with an average weight of 350 kg. Results show that there are statistical differences (p < 0,05) between initial high and low grazing pressures. Therefore, it is concluded that, the higher the initial availability, the higher the percentage of leaf area and stems, but the lower percentage of dead material, however, the leaf stem ratio decreases as the initial availability increases.