SWARD CANOPY STRUCTURE AND INGESTIVE BEHAVIOR OF GOATS IN ALEXANDERGRASS PASTURES UNDER CONTINUOUS STOCKING

Abstract

The aim of this trial was to describe the canopy structure and grazing behavior of goats in Alexandergrass swards under continuous stocking. The treatments corresponded to four sward canopy heights (10, 20, 30, and 40 cm) maintained by variable stocking density. The following variables were accessed: morphological composition; nutritive value by hand plucking; mass and density of morphological components; leaf lamina length; Time spent grazing, ruminating, and idling. The data were submitted to analysis of variance and polynomial orthogonal contrasts. The main results were: i) following the sward canopy height increments, there was an increment in forage mass (and its morphological components), as well as an inversion in morphological compositions (leaf proportion reduction and stem + dead material increment); ii) leaf lamina length increased with grazing height increments; iii) time spent grazing was increased following sward canopy height reduction, although animals apparently abdicated to graze in 10 cm treatment at the final of the experiment. Based on sward canopy structure and grazing behavior, we concluded that Alexandergrass under continuous stocking should be managed around 40 cm. Reason are discussed throughout the manuscript.
Keywords: Brachiaria; integrated crop-livestock system; management; nutritive value; Urochloa plantaginea.