This trial evaluated the inclusion of glycerin in high concentrate diets as an ingredient is able to of reducing ruminal metabolic problems, for this was evaluated the behavior feeding of 60 Nellore cattle (initial BW of 300 ± 50 kg) assigned in a completely randomized block. Diets consisted of corn silage, corn, crude glycerin (83% glycerol), urea, sunflower meal, soybean hulls and mineral. Finishing diets presented 15% of roughage and 85% of concentrate. The crude glycerin derived from vegetable used is soybean oil and 30% was included in the diets of DM. Four treatments were used: glycerin during adaptation step up and finishing period (1) or glycerin just during adaptation period (2); absence glycerin during adaptation and finishing period (3) or absence of glycerin during adaptation and finishing period (4). The animals were housed in individual pens with free access to water. The diets were offered twice daily at 0800 and 1600h with 50% of total in each meal. The data were analyzed using GLM procedure of SAS statistical software 9.2 and were compared the means by Tukey’s test considering 5% of significance level. There were no difference treatments among the variables: ruminating time, total idle, ruminating efficiency, bolus number and mastication per day (P > 0.05). The exceptions were the variables: dry matter intake, feeding time, feeding dry matter efficiency (P < 0.05). Diets with glycerin finishing promoted greater feeding time and lower dry matter intake, probably this effect is due to energy contribution of glycerin, which modulated the animal intake. Glycerin increases the frequency of meals and reduces meal size which is beneficial for ruminal fluid pH. It is concluded, that the use of glycerin results in better synchronization in time between feed intake (acid production) and rumination (saliva production).