VARIAÇÕES MICROCLIMÁTICAS SOBRE A PRODUÇÃO DE CAPRINOS EM SISTEMAS SILVIPASTORIS

Abstract

The silvopastoral system (SSP) comprises one of the modalities of agroforestry systems, in which the tree, forage and animal components are integrated in the same area in order to explore their interactions through efficient use of available resources. This type of system can be implemented using different combinations of tree species, arrangements and planting densities, which reflects on the variation in the transmission of solar radiation by the trees in the system. Among the benefits of adopting SSPs, it is possible to highlight the environmental, economic and social services. The objective of this study was to evaluate the productivity, the chemical compositions of the Brachiaria decumbens pasture, as well as the performance, ingestive behavior, and physiological parameters of goats submitted to three different tree arrangements in silvopastoral systems, in relation to a pasture area without shading. The experiment was carried out at the agroecological station of the Federal University of Recôncavo da Bahia, in the municipality of Cruz das Almas, Bahia, Brazil. Thirty-two Anglo Nubian crossbred goats, with an average age of 7 months, were randomly distributed into 4 treatments, 6 periods of 15 days, supplemented with commercial feed for growing goats. The animals were distributed in 4 different types of systems using a total area of 0.5 ha. The forage species used was Brachiaria decumbens and the main tree component was Gliricidia sepium with the following arrangements: Planting in a single line, with trees arranged in a single row obeying a spacing of 3m between trees and 12m between rows. Planting in double rows: arrangement with double rows of trees, following the spacing of 3x3m between trees and 9m between rows; and the planting of trees in clusters along the pasture using 3x2m spacing between trees, in contrast to the Brachiaria decumbens pasture without shading in order to determine performance, collection of physiological and climatic parameters. With regard to the determination of the pasture productivity of the systems for the nutritional composition, pre and post grazing evaluations were carried out at each experimental period adopted. Microclimatic conditions indicated that silvopastoral systems were more effective in mitigating environmental impacts such as radiant thermal load, ITGU and ITU, and as a result, decreased surface body temperature, respiratory rate and increased welfare and weight gain of goats. Animals kept in SSPs reduced the frequency of searching for a drinking fountain, when compared to the conventional system. The chemical composition of the leaf and stem of Brachiaria decumbens during grazing times and the crude protein content of the leaf blade were higher for the silvopastoral systems compared to the conventional system. For pasture height in pre- grazing, the highest height (54.20 cm) was observed in the forest system, followed by the single and double row systems, and the lowest height was observed for the control. It is evidenced by the study that silvopastoral systems can be used to provide a more favorable environment during grazing. Thus, silvopastoral systems can be considered an effective alternative for goat meat production.