Handling Time and Bite Mass Mechanisms in Large Herbivores: Contrasts between Sward Structure and Grazing Methods

Grazing is a time-dependent process where jaw movements of prehension, handling and chewing compete with them (Laca et al. 1994; Ungar et al. 2006). The grazing efficiency is dependent of bite mass and time per bite. Bite mass has been related to sward structure by forage height, structural components (Cangiano et al. 2002). In rotational stocking this effect becomes more pronounced, especially under high grazing down levels. Consequently, there is a progressive reduction in short-term intake rate (Fonseca et al. in press). New management targets should be proposed based on the predominant influence of sward structure in short-term intake rate by grazing animals (Carvalho et al. 2007). We hypothesise that intake potential of animals grazing tropical pastures will be reduced due to higher constraints in bite formation when compared to temperate pastures. This study aimed to investigate the intake process of heifers under the influence of different sward heights and grazing down levels in two contrasting - tropical and temperate - forage species