Methods of grazing and supplementation sources in Mulato II grass pastures: agronomic responses, root decomposition kinetics and methane mitigation potential in vitro

• Grant number: 19/23829-7
• Support Opportunities: Regular Research Grants
• Duration: May 01, 2020 - October 31, 2021
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Pastures and Forage Crops
• Principal Investigator: Carlos Guilherme Silveira Pedreira
• Grantee: Carlos Guilherme Silveira Pedreira
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Forage plant responses to the average canopy height may vary among the stocking methods employed. Studies comparing rotating stocking with continuous stocking are scarce. However, it is necessary to adapt management techniques that promote increment in accumulation and improve forage quality and carbon incorporation in soils via root biomass increment, in addition to the most diverse ecosystem services promoted by the pasture agroecosystem. In addition, grazing management can be a tool to manipulate forage digestibility and favor the reduction of methane emissions by ruminants. The manipulation of dietary substrate by supplementing animals kept on pasture has been reported as an efficient strategy to modulate rumen fermentation and reduce enteric methane production, minimizing the impact of activity on the environment and increasing overall activity efficiency. The objectives of this project are to compare and explain the agronomic performance and root decomposition kinetics of Mulato II grass in response to continuous and intermittent stocking management strategies (subproject 1); and quantifying the impact of grazing method and supplement use on methane emissions, and in vitro fiber degradability profile and kinetics (subproject 2). Subproject 1 will compare six variations of the grazing methods under mimetic continuous stocking and rotating stocking, characterized by average canopy heights of 20 or 30 cm determined as a basis for equivalent comparison between the methods and the different defoliation severities imposed. In subproject 2, the effect of grazing method (subproject 1) associated with supplementation strategies (NO3- + S elemental; soybean oil; ground corn grain concentrate; and soybean oil + ground corn grain concentrate) will be evaluated. improve in vitro fiber degradability profile and kinetics and reduce enteric methane production. The combined effects of grazing methods and supplementation on pastures are expected to rationalize plant responses and management flexibility, identifying opportunities for advances in the sustainability of pasture cattle production. (AU)