Desempenho de novilhos mantidos em pastagens de capim-elefante e capim-mombaça

Abstract

RESUMO -Foi avaliado o desempenho de novilhos mantidos em pastagens de capins elefante e mombaça no período de outubro a dezembro de 2006. Adotou-se o sistema de pastejo rotacionado, com oferta regulada de forragem. A área experimental consistia de duas repetições contendo 18 piquetes de 0,25 ha cada, divididos em nove piquetes formados de capim-elefante e nove com mombaça. Os efeitos de tratamentos foram as espécies forrageiras, a repetição de área, a interação entre estes, piquetes dentro da interação e o erro experimental. Este modelo foi usado para analisar os atributos do pasto. Para analisar o consumo, a digestibilidade e o ganho, foram aleatoriamente alocados 24 novilhos para as respectivas interações entre forragem vs. repetição vs. sistema de pastejo, o que totalizou três animais por interação tripla. Os sistemas de pastejo consistiram de pastejo ad libitum (AL) e restrito (PR). O capim-elefante apresentou maior biomassa de matéria seca total (BT) e biomassa de matéria seca verde foliar (BFV). Não houve diferença entre as forrageiras quanto à produção de biomassa de matéria seca verde foliar, no entanto a proporção de folhas foi maior no capim-mombaça. As extrusas apresentaram composição bromatológica semelhante. Apenas o consumo de proteína bruta diferiu entre as forrageiras, sendo este maior para o pasto Performance of steers raised on pastures of Elephant and Mombasa grassesABSTRACT -The performance of steers raised on elephant and mombasa grass pastures was evaluated from October to December 2006. A rotational grazing system with a regulated forage offer was adopted. The experimental area consisted of two repetitions containing 18 0.25-ha paddocks divided into nine paddocks with elephant grass and nine with mombasa grass. Forage species, area repetition, the interaction among these effects, paddocks within the interaction, and the experimental error were the effects of the treatments. This model was used to analyze pasture attributes. For analyses of intake, digestibility and gain, 24 steers were randomly assigned to the respective interactions among forage vs. repetition vs. grazing system, totaling three animals per triple interaction. The grazing systems consisted of ad libitum (AL) and restricted (PR)grazing. Elephant-grass showed the highest total dry matter biomass (TB) and green leaf dry matter biomass (GLDM). There were no differences among forage plants for production of biomass of green leaf dry matter; leaf proportion was the greatest in mombasa grass, however. Extrusas showed similar bromatological composition. Only crude protein intake, which was the highest for mombasa pasture, differed among forage plants. Ad libitum feeding enabled a higher intake of all nutrients from both pastures. Digestibility of nutrients was higher for elephant-grass but it did not differ among feeding levels: only crude protein content was the highest on pasture where grazing was restrict and gross energy content of pasture was higher for ad libitum grazing system. Despite qualitative and quantitative differe...

Enteric methane in grazing beef cattle under full sun, and in a silvopastoral system in the Amazon

“…The animal performance was similar between the evaluated systems during the rainy period, with a DM intake of more than 7 kg per day, corresponding to 3.4% of LW per day (Table 5). These values are higher than those obtained by Garcia et al (2011) in the rainy period, in a pasture rotating with 'Mombaça' grass. They observed an intake of 3.2% of LW per day and gains of 0.850 kg per day in Limosin-Nellore calves.…”

Body composition and net requirements of protein and energy for weight gain of Nellore and crossbreed steers finished under grazing

“…The rate of weight gain in animals on pasture, even under optimal conditions, would be moderate in relation to confined animals (Poppi & McLennan, 1995;Ferrell & Jenkins et al, 1998a, b;Ribeiro et al, 2008;Garcia et al, 2011). The rate of gain would be strongly and positively associated to fat deposition (NRC, 2000), which would explain mainly the lower body concentration of fat and higher body concentration of protein in grazing animals (Table 6), compared to confined animals (Fontes, 1995;Zervoudakis et al 2002;Fontes et al, 2005b).…”

Selection of Elephant-Grass Genotypes for Forage Production

“…Levels lower than 7% are limiting to animal production due to digestibility coefficients and negative nitrogen balance. The chemical composition of elephantgrass is not limiting the digestion of non-ruminal fiber, which ends up reflecting not the animal's weight gain (Garcia et al, 2011).…”