An experiment was accomplished using canola grains to evaluate in situ degradability and in vitro digestibility. The treatments was: 1) canola grains treated with water (control - CTH); 2) in autoclave at 127ºC for 30min (CTA), 3) with tannic acid (CTT) and, 4) with tannic acid followed by autoclave (CTTA). The effect of these treatments in effective dry matter (EDDM) and crude protein (ECPD) degradability was evaluated by the nylon bag technique, using two Holstein cows with rumen cannula. The effect in in vitro dry matter (IVDDM) and crude protein (IVCPD) digestibility was evaluated by DAISY system of ANKOM® Technology Corporation. The treatments heat and tannic acid applied to the canola grains increased significantly (P<0.05) the solubility of DM "a" fraction. EDDM of treatments CTA and CTTA were higher than CTH and CTT. IVDDM was identical in all treatments. The soluble “a” fraction of CP was significantly (P<0.05) reduced due to CTA treatment, and mostly to due to happened interaction of the heat and of the tannic acid tânico. The CTTA treatment was the only one that reduced ECPD (76.7%) in relation to CTH, CTA and CTT, that showed 84.7; 84.3 and 84.2%, respectively. All the treatments provided an increase in IVCPD when compared to the control (P<0.01). It is concluded that CTTA was the most suitable treatment to obtain lower ruminal degradability of canola grains, without changes in IVDDM and with a rise in IVCPD.