Sward Structural Characteristics of Perennial Peanut Genotypes as Affected by Harvest Frequency

Despite the high potential of tropical forage species, herbage production, nutritive value and animal productivity in Brazilian livestock production systems are lower than what can be obtained from both a biological and operational point of view (Pedreira and Mello 2000, Da Silva and Sbrissia 2000). Even with these limitations, the livestock industry is often able to sustain high productivity levels (animal product per hectare) by using good animal genetics and supplementation. Reducing production costs, however, will likely depend on the identification and incorporation of a high-quality forage resource, in terms of both improving diet quality of grazing animals and sustaining pasture soil productivity. The search for economically viable and sustainable forage production alternatives has been the subject of a great deal of research in many parts of the world. Among the alternatives explored, the diversification of pastures by the introduction of forage legumes in traditional production systems has been suggested, mainly to improve soil chemical characteristics (increased nitrogen levels) and improve forage quality (Perez 2004, Valentim and Andrade 2004). Promising legume germplasm is available in the tropics, but before these materials are incorporated into commercial systems, they need to be evaluated for adaptation, productivity and persistence in specific micro-environments. In addition, interactions involving grazing management strategies and genotypes should be described and explained, so that their agronomic potential can be explored. The aim of this study was to characterise sward structure of 4 perennial peanut genotypes subjected to 2 harvest management strategies, in south-eastern Brazil

Dry Matter Yield, \u3ci\u3ein Vitro\u3c/i\u3e Digestibility, Protein and Fiber Composition of \u27Tifton 9\u27 Bahiagrass (\u3ci\u3ePaspalum notatum\u3c/i\u3e) at Six Maturities

The objective of this research was to evaluate dry matter yield, in vitro digestibility, and the concentrations of protein and cell wall components in \u27Tifton 9’clipped at six maturities. Herbage was cut at the age of 20, 27, 34, 41, 48 and 55 days. The experimental design was a randomized complete block with six trataments (ages) and four replications. Dry matter yield and acid detergent fiber ranged from 188 g m-2, to 593 g m-2 and 386.9 g kg-1 to 375.1 g kg-1 respectively, with the cubic regression model having the best fit (P\u3c 0.05). Concentrations of crude protein decreased linearly (P\u3c 0.05) from 121 to 69 g kg-1. Neutral detergent fiber concentration and “in vitro” digestibility, were not affected (P\u3e 0.05) by maturity, in the range studied. Dry matter yield, digestibility and concentration of fiber components presented values similar to other tropical forages, whereas the crude protein remained above 100.5 g kg-1, only until the 27th day, according to the regression model

Methane emission from grazing dairy cattle in tropical Brasil: mitigation by improving production.

Experiments were carried out on tropical grass pasture, in summer 2002, to find out possible mitigation options to reduce methane emission using different categories of grazing dairy cattle breeds. Methane emission was measured using the SF6 tracer technique. Experimental design was a block distribution in time, along four consecutive weeks, five days a week, at 12-hour intervals, employing four animal categories - lactating and dry cows on pastures with nitrogen fertilization and heifers on pastures with and without fertilization - of pure Holstein and 3/4 breeds (B. taurus x B. indicus): lactating Hostein cows in 1 of 33 resting days rotated grazing fertilized Panicum maximum with 15% crude protein (CP), 64% neutral detergent fiber (NDF) and 54% ?in vitro? organic matter digestibility (IVOMD) plus 1 kg concentrate with 20% CP for each three liter milk surplus above 10 liters; dry cows and heifers of both breeds grazing N-fertilized grass P. maximum, lactating Zebu crosbred on Nfertilized Brachiaria decumbens, and heifers of both breeds grazing unfertilized B. decumbens extensively managed, with 6.5% CP, 72% NDF and 37% IVOMD, similar to the most representative cattle production systems in Brazil. These experiments were carried out in summer (rainy season) with offer of good quality grass forage. Data indicate that methane emission rates of cattle on tropical grass pastures are higher than those on temperate forages, perhaps due to higher fiber content. Data also suggest that improvement of production potential of dairy cattle may reduce methane emission per product unit in Brazilian summer grazing conditions. Concentrate use equal or lower than 40% of dry matter intake did increase methane emission per animal but reduce per unit of production

Verminose em bezerros nas regiões úmida e semi-árida de Sergipe.

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