Sistemas silvipastoris: impactos sobre o conforto animal.

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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

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

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Los sistemas silvopastoriles en las regiones subtropicales del Brasil: las actividades de la EMBRAPA.

En Ias regiones subtropicales dei Brasil hay una gran oportunidad para el establecimiento de sistemas silvopastoriles. En esta región, Ias sistemas dominantes de uso de Ia tierra son Ias actividades agrícolas (maíz, soja, trigo, frijol, arroz, etc.) y ganaderas (producción de carne y leche bovina y ovina). Hay presiones económicas y ambientales que actúan en el media rural sobre Ias productores tendientes a adaptar sistemas de uso de Ia tierra más sostenibles. Si bien existen pruebas científicas y ejemplos de aplicación, Ia diversidad de condiciones regionales aconsejan desarrollar más estudios y mecanismos de política pública para promover Ia conversión de Ias pastizales sin árboles aios sistemas silvopastoriles

Opportunities and challenges of integrated systems in animal production: emphasis on silvopastoral systems

The use of integrated crop-livestock-forest systems can be an important strategy for increasing the sustainability of animal production in tropical regions. The benefit of such systems include increased soil fertility and conservation, improved thermal comfort for the animal, increased forage quality and possible income diversification, in addition to increased atmospheric carbon sequestration. The challenges to the development of these systems are related to high economic investments and lack of competent technical assistance. The benefits of integrated systems depend on achieving balance among its components, as competition for resources for growth can render the system unsustainable

Evaluation of New Dwarf Elephant Grass Genotypes for Grazing

Elephant grass stands out for its production potential, forage quality and acceptance by animals. However, its tall size makes management under grazing difficult and dwarf cultivars have been selected and evaluated to overcome this limitation. The objective was to characterize agronomic aspects of dwarf elephant grass genotypes submitted to two defoliation intensities. The experiment was installed in a 5 x 2 factorial scheme, with five elephant grass genotypes (2022, 1810, 2111, 2035, BRS Kurumi) and two residue heights after defoliation (25 and 45 cm). A randomized block design with three replications in 4x3m plots was used. Forage above the residue height was cut whenever the canopy reached 93-95% light interception. Residue heights did not influence leaf/stem ratio, basal and total tillering, and dry matter production. On the other hand, influence of residue height on canopy height, aerial tillering and forage accumulation rate was observed. The forage accumulation rate increased by 19% for the 45 cm residue compared to the 25 cm residue. No interaction was observed between genotype and residue height for the variables canopy height, leaf:stem ratio, basal tillering, aerial tillering, forage mass and forage accumulation rate. In relation to tillering, BRS kurumi showed greater total and aerial tiller number, 31% higher than the average of the other materials. Although the cultivar BRS kurumi has more vigorous tillering, the variables leaf:stem ratio and forage accumulation rate were higher in the new materials, especially material 1810, which presented better performance compared to the control. In view of this, it is concluded that the new grass genotypes have a higher proportion of leaves and forage accumulation rate than BRS Kurumi, and that the residue height of 45 cm provides a higher forage accumulation rate

Características anatômicas de híbridos de "Sorghum bicolor" com "Sorghum sudanense".

Dezesseis híbridos de Sorghum bicolor com Sorghum sudanense,12 experimentais e quatro comerciais, foram cultivados, entre os meses de março e junho de 2003, com objetivo de se obter informações sobre a proporção de tecidos nas lâminas foliares. Foram realizados três cortes sucessivos, aproximadamente a cada 40 dias de crescimento das plantas. As proporções de epiderme, esclerênquima, bainha parenquimática dos feixes, xilema, floema e mesofilo ou parênquima clorofiliano foram determinadas em seções transversais da lâmina foliar. Foi usado o delineamento de blocos ao acaso, em esquema de parcela subdividida, com três repetições. Nas parcelas foram alocadas as cultivares e na subparcelas, os cortes. Não foi detectada diferença entre os híbridos para a proporção de tecidos. Entre os cortes, foi observada redução da proporção de xilema, esclerênquima e tecidos lignificados e aumento das áreas de mesofilo e tecidos não-lignificados, à medida que os cortes se sucederam

Herbage Mass, Forage Accumulation and Nutritive Value of \u3cem\u3eBrachiaria decumbens\u3c/em\u3e in a Silvopastoral System

The use of silvopastoral systems has been suggested to ensure sustainability in animal production systems because of their potential to increase soil fertility, improve forage quality, promote animal thermal comfort and provide income diversification for the producer (Paciullo et al. 2011). Nevertheless, the shade provided by trees may affect plant growth and nutritive value of forage (Sousa et al. 2010). This study aimed to assess the impact of shading on the allocation pattern of dry matter and on herbage nutritive value, under various shading regimes, in a silvopastoral system, during both the dry and rainy seasons