Morphogenetic and structural characteristics, yield and chemical composition of signal grass under deferred grazing

Abstract

ABSTRACT The effects of four deferred grazing strategies (30, 60, 90 and 120 days) on morphogenic and structural characteristics, herbage accumulation, and chemical composition of signal grass (Brachiaria brizantha cv. Xaraés) were evaluated. The experiment was conducted in Rondonópolis, Mato Grosso, Brazil, during the transition period between the rainy and the dry season, from April to August 2013. The number of live leaves and leaf lifespan were quadratically affected (p < 0.05) by the period of deferment. Pasture height linearly increased (p < 0.05) with increasing deferment periods, reaching a maximum of 54.33 cm at 120 d of deferment. The leaf: stem ratio linearly increased (p < 0.05) with increasing deferment periods and remained higher than 1 during all evaluation periods. Total dry matter accumulation increased linearly (p < 0.05), with an average of 7817 kg/ha at day 120 of the deferment. Concentrations of crude protein and neutral detergent fiber were not affected by the length of the deferment period (p < 0.05). A deferment period of up to 120 days resulted in increased dry matter accumulation, a higher leaf: stem ration, and only slight changes in the structural characteristics and chemical composition of Xaraés pasture grass.