MELHORAR A DISTRIBUIÇÃO TÉRMICA EM SISTEMAS DE PASTEJO FAVORECE ATIVIDADES COMPORTAMENTAIS DE BOVINOS DE CORTE

Abstract

This study proposes to elucidate how thermal distribution in grazing systems with different tree densities can influence the behavioural activities of beef cattle in central Brazil. The experiment was laid out in a randomized complete block design with a split-plot arrangement, in four replicates. We evaluated the spatiotemporal thermal distribution within two silvopastoral systems with 89 and 113 trees ha-1 and a system with an unshaded pasture of Brachiaria brizantha cv. BRS Piatã during the summer of 2020. The analysis was based on the black globe temperature (Tbg), infrared thermography (IT), and the main feeding behaviour-related activities and displacement of 80 male Nellore cattle using bioacoustics and a global positioning system. The presence of trees at different densities affected the spatiotemporal thermal distribution, with an average difference of up to 4.7 °C in Tbg between the systems, and that better spatial exploration is possible in those with the presence of shade. The longest time spent grazing occurred between two hours (average of 44.7 min h-1, in the non-shaded system) and three hours (average of 44.5 min h-1, in the silvopastoral systems) after the peak of Tbg (39.2 °C), whereas the other activities (idleness, rumination, water consumption, and mineral consumption) were carried out predominantly at night. Therefore, the better thermal distribution in silvopastoral systems favours the grazing activity of beef cattle on pasture during the daytime period, allowing the animals to select the nocturnal period for rest and rumination.