Forage yield and grazing efficiency on rotationally stocked pastures of 'Tanzania-1' guineagrass and 'Guaçu' elephantgrass

Scientia Agricola

Carlos Guilherme Silveira Pedreira²  Frederico Alberto De Andrade Rosseto²  Sila Carneiro Da Silva²  Luiz Gustavo Nussio²  Leonardo Simões De Barros Moreno²  Maria Lúcia Pereira Lima¹  Paulo Roberto Leme¹ 

[1] ,USP ESALQ Depto. de ZootecniaPiracicaba SP ,Brasil

关键词: losses due to grazing;    forage accumulation;    accumulation rates;    forage allowance;    perdas por pastejo;    acúmulo de forragem;    taxa de acúmulo;    oferta de forragem;   

DOI  :  10.1590/S0103-90162005000500004

来源: SciELO

【 摘 要 】

The potential carrying capacity of tropical pastures depends not only on the productivity of the forage species and the amount of forage on offer, but also on the efficiency with which the produced herbage is harvested by the grazing animal. This study was conducted to assess the yield and grazing efficiency on 'Guaçu' elephantgrass (Pennisetum purpureum Schum.) and 'Tanzania-1' guineagrass (Panicum maximum Jacq.) pastures under rotational stocking. Forage accumulation, daily accumulation rates, grazing losses, bulk density, and utilization efficiency were measured. Treatments (forages) were replicated four times in a completely randomized design. Total forage dry matter (DM) yield over 214 days of grazing were 23850 and 15000 kg ha-1, for the elephantgrass and the guineagrass, respectively, using 250 kg N ha-1 in split applications after each grazing. Mean forage accumulation per grazing cycle was 7950 and 5010 kg ha-1 and mean daily accumulation rates were 137 and 86 kg-1 ha-1 d-1 for P. purpureum and P. maximum, respectively. Grazing losses per cycle averaged 1040 and 880 kg ha-1, for grazing efficiencies of 52 and 37% for the Pennisetum and the Panicum, respectively. Mean seasonal stocking rate was 5.1 AU (animal unit = 500 kg LW) per ha on P. purpureum and 3 AU ha-1 on P. maximum pastures. For both species, productivity potential resides on the high pasture carrying capacity, particularly when there are no soil fertility limitations during the warm/rainy season. Based on growth potential and stem elongation characteristics, 'Guaçu' requires better management skills and 'Tanzania-1' has a more pronounced seasonal growth, as expressed by seasonal yields, apparently due to their contrasting responses to temperature and daylength.

【 授权许可】

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