Productivity and nutritive value of elephant grass pastures under organic and conventional production systems

Abstract

Elephant grass (EG) (Pennisetum purpureum Schum.) have great importance in tropical and subtropical climates, especially on dairy farms. Normally, EG is established alone under high fertilization levels. EG in organic production system can improve low production costs and environmental issues, are still little known. The aim of this research was to evaluate the performance of herbage yield, nutritive value, extraction/ export nutrient and forage yield and animal responses. Three production systems of EG were analyzed: (i) EG mixed spontaneous-growing species (SGE) in warm-season and ryegrass (R) in cool-season under organic production; (ii) EG mixed SGE + R under conventional system (positive control); and (iii) EG based under conventional production (control). Holstein cows were used in a rotational stocking. Forage samples were collected to evaluate the pasture and animal responses. Seven grazing cycles were performed during the experimental period (312 days). Herbage yield, forage intake, and stocking rate were 12548; 10270; 19168 kg ha-1 and 2.5; 2.6; 2.7% and 3.3; 2.1; 4.5 AU ha-1 day-1, respectively. Crude protein of EG was 17.9; 15.4; 16.4%, respectively. Mixed pastures, in conventional and organic production, had a better forage distribution throughout the seasons. Highest forage yield and extraction/ export nutrient was reported in pure EG within the conventional system.