Marandu palisade grass‐forage peanut mixed pastures: Forage intake, animal behaviour, and canopy structure as affected by grazing intensities

Abstract

Integrating forage legumes into grasslands offers numerous ecosystem services. However, the management of grass‐legume pastures is challenging because the interaction between the defoliation frequency and severity may affect the legume persistence and forage intake by grazing animals. This 2‐year study evaluated the most effective grazing intensity to increase forage intake while maintaining a balanced legume proportion in tropical pastures consisting of Brachiaria brizantha and Arachis pintoi. Three treatments (grazing intensities) were assessed: severe, moderate, and low, corresponding to stubble heights of 10, 15, and 20 cm, respectively, and a pre‐grazing height of 25 cm. Two purebred Tabapua heifers were used for each treatment, and additional put‐and‐take animals were introduced, as required. Canopy structure, grazing behaviour, nutritive value, and forage intake were evaluated. The legume proportion in herbage mass remained consistent across all intensities, averaging 35% pre‐ and 32% post‐grazing. The grazing duration remained consistent across treatments on the first and third days, with an average grazing time of 390 and 440 min, respectively. Under post‐grazing conditions, low‐intensity grazing had a 52% greater intake rate than severe‐intensity grazing, which was attributed to a greater biting rate (37.9 bites/min) and bite weight (0.9 g DM/bite). Moderate grazing intensity (stubble height of ~15 cm associated with a pre‐grazing height of ~25 cm) is recommended to manage a mixture of B. brizantha and A. pintoi when the objective is to couple high forage intake with a balanced legume proportion in the pasture.