Agronomic characteristics and nutritive value of elephant grass clones managed under rotational stocking during the dry period.

This study aimed to evaluate the agronomic characteristics and nutritional value of two clones of elephant grass (CNPGL 00-1-3 and BRS Kurumi) operating under rotational stocking in the dry season. A completely randomized design with repeated measures (grazing cycles) and three replicates (paddocks) was used. Clones were managed under rotational stocking with a defoliation interval of 24 days and four days of occupation of paddocks, using Holstein x Gyr heifers with mean body weight of 150 kg. The evaluations were conducted in April/May, May/June, June/July and July/August 2010. Green forage mass was influenced by clone and grazing cycle, with higher mean value observed for CNPGL 03-01-00, which was 17% higher than the value observed for BRS Kurumi, and there was decreased of dry mass of green forage with the advance of grazing cycles. Leaf mass was influenced only by grazing cycle, with gradual reduction from the first to the third cycle. However, in fourth cycle was increase in biomass of leaves, which did not differ from that observed in the second cycle. There was interaction for dry matter production of stem, being observed differences in the first and third cycles for the clones. There was no effect of the factors studied for the production of senescent material. The leaf:stem ratio was influenced by grazing cycles, with interaction of the factors studied. The clone BRS Kurumi kept the leaf:stem ratio stable over the cycles, while clone CNPGL 1-3-00 presented a decrease in leaf:stem ratio from first until to third cycle. The content of crude protein (PB) was not influenced by the factors studied, with average values of 15.3% and 15.8% PB for the CNPGL 00-1-3 and BRS Kurumi clones. Neutral detergent fiber (NDF) and the in vitro dry matter digestibility (IVDMD) were affected only by grazing cycles. The highest values of NDF were observed in the three first grazing cycles, with values of 55.5%, 56.0% and 55.7% from the first to the third grazing cycle, respectively, while in the fourth cycle was obtained the value of 50.5%. There was a decrease in the IVDMD until the third cycle. In the fourth cycle the IVDMD values were similar to the first cycle. The clones did not differ in relation to biomass production, morphological composition and nutritional value, during the dry season

Ruminal fermentation and degradation, kinetic flow of the digesta and milk fatty acid composition of cows fed chopped elephantgrass supplemented with soybean oil.

Abstract The aim of this study was to evaluate the ruminal parameters of fermentation and degradation, kinetic flow of rumen digesta, and milk fatty acid composition of cows fed 52% chopped elephantgrass-based diets containing 0.0% (control), 1.5%, 3.0% and 4.5% soybean oil (SO) on a dry matter (DM) basis. Four rumen-cannulated Holstein x Gyr dairy cows with an average milk production of 15.6 ± 3.0 kg day-1 and 90 ± 25 days in milk were allocated in a 4 x 4 Latin square design. The results were analyzed by mixed models. Significant differences were declared at P&#8804;0.05, and P-values from 0.05 < P &#8804; 0.10 were considered as a trend. The inclusion of SO in the diet had no effect on the ruminal pH or total volatile fatty acid concentration, but there was a quadratic effect on the ruminal ammonia nitrogen content and a trend for a linear reduction (P=0.07) in the molar proportion of rumen acetate. Linear reductions were also observed in the DM and neutral detergent fiber (NDF) effective degradabilities of elephantgrass forage, but the fluid and particulate passage rates in the rumen and the DM and NDF intakes were unchanged by SO inclusion in the diet. Milk production, protein and lactose contents and yields were unaltered by dietary SO levels. There were linear reductions in the milk fat and total solids contents, but there was no effect of dietary treatments on their yields. The inclusion of soybean oil in the diet of Holstein x Gyr cows fed chopped elephantgrass improved the nutritional quality of milk fat as a result of increased contents of oleic, rumenic and vaccenic acids, which are beneficial to human health, and a concomitant reduction in hypercholesterolemic saturated fatty acids such as lauric, myristic and palmitic acids

Fibra efetiva para vacas em lactação.

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Frações nitrogenadas e de carboidratos em dietas com inclusão do resíduo de panificação em substituição ao milho.

Objetivou-se com o presente trabalho determinar as frações de carboidratos e de compostos nitrogenados de dietas com inclusão do resíduo de panificação (RP) em substituição ao milho. Foram utilizados cinco níveis de inclusão (0,25,50,75 e 100%) do RP em substituição ao milho. As rações concentradas foram compostas por milho, farelo de soja e RP. Foram determinados os teores de carboidratos totais, as frações de carboidratos e as frações dos compostos nitrogenados dos alimentos e das dietas. O RP destacou-se por promover aumento nos teores das frações A+B1, tanto de carboidratos quanto de proteínas, o que permitiria melhor sincronismo na disponibilidade energética e de compostos nitrogenados no rúmen, resultando no aumento da eficiência da síntese microbiana. Os resultados obtidos indicam que o RP apresenta características que o credenciam como potencial substituto do milho

Emissões de metano na pecuária: conceitos, métodos de avaliação e estratégias de mitigação.

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Produção de forragem e valor nutritivo de clones de capim-elefante anão sob estratégias de desfolha intermitente.

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Pruning height in Eucalyptus clones established in an agrosilvopastoral system.

The aim of the current study is to evaluate the effect of pruning intensity on the diameter and height of three Eucalyptus clones established in an agrosilvopastoral system. The study followed a completely randomized block design in a split-plot arrangement, with repeated measures in time. Plots were represented by three Eucalyptus clones (VE01, VE07 and VE06) and sub-plots were represented by three pruning heights (0%, 25% and 50% of total tree height), and the repeated measures were months. Trees were pruned at 18 and 24 months after planting, by keeping the same proportion of pruning Heights. Diameter at Breast Height (DBH) and total Tree Height (Ht) were measured every six months since the first pruning; periodic increase in both variables was calculated. Clone VE01 recorded DBH and Ht values lower than the ones recorded for VE07 and VE06. Pruning treatments did not show significant effects on tree growth