Dynamics of production and forage utilization on elephant grass pastures managed with different post-grazing heights

Braulio Maia De Lana Sousa,Domicio Do Nascimento Júnior,Hélida Christhine De Freitas Monteiro,Dilermando Miranda Da Fonseca

doi:10.1590/s1516-35982012000800006

Braulio Maia De Lana Sousa, Domicio Do Nascimento Júnior + Show 2 more

Open Access

https://doi.org/10.1590/s1516-35982012000800006

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Abstract

This study was conducted to evaluate the daily production of forage and its morphological components, as well as the potential of forage utilization in pastures of Pennisetum purpureum cv. Napier managed with three post-grazing heights (30, 50 and 70 cm). Two experiments were carried out: one from February to May 2009 and another from December 2009 to May 2010, characterizing months of summer and fall. The experimental design was of completely randomized blocks with three replicates. The grazing was performed by crossbred heifers of approximately 270 kg body weight, when the sward intercepted 95% of the incoming light. In both experiments, the pastures managed with post-grazing height of 30 cm, in the summer months (December to March), presented lower daily production of leaves and stems, as well as less daily leaf senescence, which resulted in lower daily forage production and accumulation in comparison with those managed at 70 and 50 cm. In the period from February to March 2009 (experiment 1) and December 2009 to March 2010 (experiment 2), pastures presented greater daily production of leaves and forage, greater daily forage accumulation and more daily leaf senescence in relation to the months of April and May 2009 and 2010. On the other hand, the daily production of stems was higher in the fall, in comparison with the summer. Therefore, elevation in the post-grazing height, especially in the summer, increases the regrowth vigor of elephant grass cv. Napier.

Highlights

Elephant grass (Pennisetum purpureum Schum.) is a perennial grass, with caespistose growth which can form dense tussocks by means of abundant basal and aerial tillering
The management of elephant grass under pasture has been recommended based on the utilization of fixed rest periods or animal entry heights of 1.70-1.80 m (Deresz et al, 2006), which is a type of management that hampers control of the stem elongation and leaf senescence processes (Da Silva & Nascimento Júnior, 2007)
The experiment was conducted in an area of the Forage Sector of Universidade Federal de Viçosa (UFV), in Viçosa, Minas Gerais, Brazil (20o 45' S; 42o 51' W and 651 m), with elephant grass cv

Summary

Introduction

Elephant grass (Pennisetum purpureum Schum.) is a perennial grass, with caespistose growth which can form dense tussocks by means of abundant basal and aerial tillering. Pastures managed with post-grazing height of 70 and 50 cm presented greater daily leaf production between February and April 2009 in comparison with those managed at 30 cm; differences were over in May. Overall, the daily leaf production was elevated in February and March, in relation to April and May (Table 2). In experiment 1, the daily production of stems was affected by the post-grazing height × month interaction (P = 0.0010).

Results

Conclusion