This study aimed to describe the feeding and spatial behavior of beef heifersunder rotational stocking, in response to the dynamics of the morphologicalfunctional types (TFs) in natural grassland. Stocking rate was adjusted to keepan average of 12% (12 kg DM/100 kg BW) of forage allowance. Animal activitywas registered from 12 to 27 February 2003 using the Ethosys automatic device.Thirty permanent field sampling units comprised by five adjacent 0.20 x 0.20m squares were used to determine pasture attributes. Results showed the existenceof an optimum subset of two attributes to describe pasture plant community:the aerial and the lignified (woody) forage biomasses, which defined eight morphologicalfunctional types that had a 0.43 congruency value with the variable degree-day.The evolution of grazing activity showed that grazing time increased as thefrequency of preferred functional types decreased. Thus, the morphological characterizationof functional type-based attribute definition can bring more contributions forthe interactive response between the vegetation and the animal behavior thanthe one realized using only the taxonomic identification. Therefore, in a simultaneousaction, as the vegetation change, the animals modulate the behavior adjustingtheir rhythm of activity in time and space, determining, in a continuous process,differential impacts in the vegetation, which evolves with time.
