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The objective of this study was to verify the activity of invertases in Estilosantes under the influence of cultivation systems and nitrogen fertilization in two seasons. The experiment was conducted in the Xaraés area, where Estilosantes was planted according to a 2 x 2 factorial scheme with two cultivation systems (monoculture and mixed pasture) in the absence or presence of fertilization (75 kg of N ha-1). A randomized block design with four replications was used. The neutral cytosol (Inv-N), vacuole acid (Inv-V) and cell wall acid (Inv-CW) invertase activity and reducing sugar contents in the leaves and stems were evaluated and analyzed by a 5% probability F-test. The interaction between cultivation systems and nitrogen fertilization was significant for Inv-N in the leaves in the summer, such that greater activity occurred in response to the mixed pasture system and nitrogen fertilization. Nitrogen increased the activity of the Inv-N in the stem in both periods, increased the activity of Inv-V in the leaf in the summer, and decreased the activity of Inv-CW in the fall. This cultivation system influenced the activity of Inv-N regardless of the period of the year and did not interfere with the activities of the acid invertases. The invertases did not show regular changes in relation to nitrogen fertilization.

The objective of this study was to evaluate the correlations existing between nutrient intake and ingestive behavior of crossbred steers in the post-weaning phase on Brachiaria brizantha cv. Marandu, during the rainy period. Twenty-two steers were distributed into a completely randomized design, with two types of supplement and eleven replications, managed under rotational grazing, in a 6.5 ha area. Pearson's Linear Correlation analysis was performed between the behavior variables and the performance variables values. The correlation coefficients were tested by the t test. The average daily gain (ADG) showed positive correlation with the times spent ruminating and eating at the trough and total chewing time. Positive correlation was observed between the idle time and feed conversion (FC). The bite rate and the number of bites per day presented positive correlations with ADG. Positive correlations were found between the variables rumination efficiency of dry matter (DM) and of neutral detergent fiber (NDF) with ADG. The ingestive behavior has a direct influence on the productive performance of crossbred steers post-weaned on pasture during the rainy period. Rumination efficiency improved when the animals were fed protein supplementation, which led to better utilization the ingested feed.