Different grazing frequencies modify the structure, production, and nutritional value of ‘Zuri’ Guineagrass in the Brazilian Cerrado.

RODRIGUES, J. G.; DIFANTE, G. dos S.; MONTAGNER, D. B.; EUCLIDES, V. P. B.; ARAÚJO, A. R. de; PEREIRA, M. de G.; MONTEIRO, G. de O. A.; SANTANA, J. C. dos S.; NOBRE, A. A. A.

Different grazing frequencies modify the structure, production, and nutritional value of ‘Zuri’ Guineagrass in the Brazilian Cerrado.

Autores

MONTEIRO, G. de O. A.

SANTANA, J. C. dos S.

NOBRE, A. A. A.

Descripción

ABSTRACT - The increasing climate variability in tropical regions demands management goals that allow for shorter rest periods without compromising pasture persistence. The objective of this study was to evaluate the effects of four pre-grazing light interception (LI) levels on the structural, productive, and nutritional responses of ‘Zuri’ guinea grass over two growing seasons. The experiment followed a randomized block design with four treatments (80%, 85%, 90%, and 95% LI) and four replications (16 paddocks of 0.045ha). The pastures were managed using the mob stoking grazing method. LI was measured using a ceptometer and used directly as a management target. The response variables were analysed using mixed models (PROC MIXED, SAS). Significant interactions between LI×year (p<0.05) were observed for canopy height, FM, FA, FAR, and TD. Linear increases in canopy height, FM, and FA with higher LI were more pronounced in the second year. With an LI of 80%, FM, FA, and TD decreased in the second year, indicating lower structural and productive stability. In contrast, pastures managed with LI between 85% and 95% maintained a stable canopy structure between years, with increased production. Morphological composition and nutritional value were affected only by the LI (Low Intake): increasing the LI reduced the percentage of leaves, crude protein, and digestibility, while increasing the stem, dead matter, and fibre content. LI targets of 85% and 90% provide a balance between grazing frequency, forage quality, and structural stability, representing flexible and sustainable management strategies under varying climatic conditions.