The objective of this observational study was to describe grazing and ingestive behavior of Nellore cattle under field conditions fed 2 grain supplementation strategies during the dry season. Forty-eight finish Nellore bulls (±340 kg of initial body weight and ± 20 mo of age) were blocked by body weight and assigned to 6 paddocks of 2.4 ha each of Brachiaria brizantha ‘Marandu’ pastures. The experiment was conducted as a randomized complete block experiment with 2 treatment factors for 140 d from May to September 2012. Treatment factors consisted of 2 levels of grains supplementation - 1.5% BW/daily (DMI) (SUPL1.5) and 2.0% BW/daily (DMI) (SUPL2.0) offered once a day (at 8 a.m.). Were evaluated the animals daily grazing time and time spent near the trough (min/day) during continuous 72h after supplementation, with intervals of 5 min. The observation occurred in 2 different period – Day (8 a.m. until 7:59 p.m.) and Night (8 p.m. until 7:55 a.m.). Data were analyzed using the MIXED procedure of SAS with sampling time serving as a repeated measure. Paddocks served as the experimental unit. The SUPL1.5 animals had greater (P < 0.01) grazing activity than SUPL2.0 (298.5 min and 244.2 min, respectively). Although, SUPL2.0 animals spend 20% more time near to the trough compared with SUPL1.5 animals (P < 0.01). Period significantly affected grazing time, with animals spend more time in grazing activity during the day (166.6 min) compared with the night (104.7 min; P < 0.01). The time spend near to the trough was greater during the day period (P < 0.01), increased rapidly in the firsts 3 h after the grain supplementation. This study indicates that the high supplementation (2.0% of the body weight) decrease the grazing time and increase the time spent near to the trough. Supported by CNPq/BELLMAN.