What Factors Control the Crude Protein Content Variation of a Basaltic “Campos” Native Grassland of South America?

Abstract

Native grasslands are the main source of food for livestock in the Campos region of South America. These forage resources are heterogeneous in species composition, grazing management, and soil fertility within a context of variable climate, all of which are factors that affect forage crude protein content over time and space. Despite the importance of protein in livestock nutrition, there is a gap in the knowledge of how fertilisation, sward height, and soil water availability influence the crude protein content of these grasslands. We used data from a long-term fertilisation experiment to construct a structural model aiming to identify the main factors influencing forage crude protein content of a basaltic native grassland in northern Uruguay. The structural model revealed that both fertilisation and the increase in soil water availability (through the improvement of the nitrogen content of green leaves) are the main pathways by which forage crude protein content increases. This new approach (which identifies and quantifies the main factors that drive forage crude protein content of native grasslands) could be used to support prediction models for forage protein content in order to improve grazing livestock nutrition of Campos native grasslands.

Grassland Ecology and Ecosystem Management for Sustainable Livestock Performance

“…(1) Forage quality and animal performance [17][18][19][20] (2) Animal grazing behavior [21] (3) Fatty acid (FA) profiles of various forages [22,23] (4) Ecosystem health for production animals [24][25][26] (5) Technology for improving management [27] 2.1. Forage Quality and Animal Performance Tracy et al [17] found that adding nutritionally high-quality, summer-productive forages, such as alfalfa (Medicago sativa) or sericea lespedeza (Lespedeza cuneata (Dum.…”

“…Núñez et al [19], using data from a long-term fertilization experiment, identified the main factors influencing the forage crude protein content of a basaltic native grassland in northern Uruguay. The authors found that fertilization and increased soil water availability were the main factors increasing forage crude protein.…”

Supplement feed efficiency of growing beef cattle grazing native Campos grasslands during winter: a collated analysis

“…Additionally, SFE might depend on the quantity and quality of herbage on offer, which depends on management of autumn stockpiling and winter stocking rate ( Fedrigo et al, 2022 ; DoCarmo et al, 2018 ). Furthermore, in contrast to rangelands in other climates, Campos grasslands retain variable amounts of green biomass over winter, depending on the proportion of C3 species present in the sward and the number and intensity of frosts, which may affect the protein concentration of available herbage ( Nuñez et al, 2022 ).…”

The defoliation dynamics of a stockpiled native grassland pasture follow similar patterns between supplemented and unsupplemented beef calves

“…Therefore, it is unclear to what extent and on which variables does supplementation affect animal selectivity and sward structure, particularly on native grasslands. Particularly, little is known about these processes when animals graze stockpiled herbage of grasslands that combine cool and warm season species and thus constitute horizontally and vertically heterogeneous mixtures of green and dead tissue (Cazzuli et al, 2023; Núñez et al, 2022).…”

“…Therefore, it is unclear to what extent and on which variables does supplementation affect animal selectivity and sward structure, particularly on native grasslands. Particularly, little is known about these processes when animals graze stockpiled herbage of grasslands that combine cool and warm season species and thus constitute horizontally and vertically heterogeneous mixtures of green and dead tissue (Cazzuli et al, 2023;Núñez et al, 2022). Some studies of foraging behaviour of ruminants have been carried out on native grasslands of the Pampa Biome (Da Trindade et al, 2012Gonçalves et al, 2009), but no studies have been conducted aiming to characterize successive grazing strata, nor its interaction with concentrate supplementation.…”