The objective ofthis study was to evaluate the Brachiaria brizantha cv. Marandu canopystructure maintained at different grazing heights under a continuous stockingrate and with a dietary supplementation strategy for the animals during therainy season. This study also intended to observe the relationships of thesevariables with the grazing behaviors of the heifers. The effects of three canopyheights (15, 25 and 35 cm) were evaluated in association with three types ofsupplements: one mineral and two protein/energy supplements, the first witha high rumen degradable protein and energy and the others with a low ratio.Both the protein/energy supplements were provided at 0.3% of body weight/day.The experimental design was completely randomized, with two replications andrepeated measures, and took place during the period from January to April 2008.The supplementation strategies did not affect any variable related to the canopystructure. Total and green herbage masses and the ratio of green/dead materialincreased with canopy height. The leaf/stem ratio was higher in the lowest canopyheight: 15 cm. Changes in the canopy structure caused variations in the grazingbehavior of the animals. Animals maintained in the 15-cm-tall pasture grazedfor a longer time, increasing the time for each meal, but the number of mealswas lower than that of the animals grazing within the 35-cm-tall pasture. Thegrazing time of animals receiving the energy/protein supplement was lower onlyin the period of the day during which it was supplied. Canopy structure is affectedby sward height, and changes animal behavior. Supplementation does not affectthe canopy structure of the pastures with similar heights.
