Content area
Full text
Introduction
In Brazil, dairy and beef cattle livestock production is mainly pasture based, which contrasts with practices in many other countries, in which most animals are fed in feedlots. Brazil has a pasture area of approximately 180 million hectares, comprising both native and cultivated pastures (Parente and Ferreira, 2018), which accounts for a major proportion of Brazilian agricultural land.
In recent years, there has been an increase in stocking rate in Brazilian pasturelands, as a consequence of pasture intensification, which has led to improvements in livestock production (Martha Junior et al., 2012). In intensive systems, quantifying forage mass and its nutritive value is essential with respect to determining carrying capacity, supplementation, and management strategies. Pasture growth depends on post-grazing stubble mass and residual leaf area in rotational stocking systems (Parsons et al., 1988), and the determination of these characteristics makes an important contribution to decision-making on pasture management (Wachendorf et al., 2017; Pezzopane et al., 2019).
In addition to quantifying forage mass for the determination of nutritive value, information relating to parameters such as crude protein and nitrogen contents can assist farmers in balancing animal diets. Furthermore, pasture nutritive value is related to animal production and is essential for high-performance dairy production (Starks et al., 2006; Pullanagari et al., 2012).
The productive characteristics of pastures can be estimated through both direct and indirect methods. Direct methods, based on the cutting and weighting forage samples, are more laborious and challenging to apply over large areas (Sanderson et al., 2001). Moreover, such methods can be prone to errors, attributable to the high spatial variability of forage mass. The sources of these errors include differences in grazing behavior, forage management, random distribution of animal excreta, and other factors related to soil and topography (Ogura and Hirata, 2001; Pullanagari et al., 2012).
The use of nondestructive methods to estimate forage mass can be more profitable for integrating the spatial variability of this variable, thereby facilitating more accurate estimates and better decision-making on pasture management (Serrano et al., 2016a; Pezzopane et al., 2019). The use of indirect methods enables the rapid and relatively inexpensive acquisition of adequate information for large areas, indicating forage yield variability and thus improving farmers’ decision-making...