Management Targets to Maximize Short-Term Herbage Intake Rate

Besides grazing, the animals carry a host of other essential activities to their survival, such as rumination, vigilance and idling, and these activities compete with each other in the animal’s daily time (Fonseca et al. 2012). Therefore, any management action that provides an increase in forage intake rate, with a consequent reduction in the time necessary to achieve the daily nutrient requirements, is essential for an animal product-ion success. In this study, four experiments were performed based upon the hypothesis that different sward structures, formed by distinct sward surface heights (SSH) and levels of grazing down influence the short-term herbage intake rate (STIR)

Relationship between Grazing Jaw Movements and Time Per Bite in Cattle: Effect of Sward Structure and Grazing Methods

The time per bite is the result of the interaction between mouth morphology, animal behaviour and sward structure (Laca et al. 1994). The time per bite increases with bite mass (Laca et al. 1994), but it has a constant component that is the time required to open and close the jaws, namely, the time required for one jaw movement (Hirata et al. 2010, Newman et al. 1994). In this experiment we tested the hypothesis that the time per jaw movement will remain constant independently of sward structure and grazing method

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