This study aimed at evaluating the influence of a silvopastoral system (SPS) composed of ''Aroeira'' trees (Myracrodruon urundeuva) on the nutritional value of Brachiaria brizantha cv. Marandu forage grass over the rainy season. The experiment was conducted in the SPS located in the ''Cerrado'' biome in Lagoa Santa County, Minas Gerais state, Brazil, in the agricultural year of 2004-2005. It was evaluated the influence of ''Aroeira'', whose density in the area was 140 trees/ha, on the following parameters of the B. brizantha cv. Marandu forage grass: forage mass harvest above stubble height, morphogenic attributes, bromatological composition and nutritional value. The effects of ''Aroeira'' trees on the micro-climatic conditions were also evaluated. The experiment adopted a randomized block design with five blocks (cutting seasons), two treatments (a shaded pasture-B. brizantha cv. Marandu shaded by M. urundeuvaand a pasture in full sun-B. brizantha cv. Marandu in full sun), and three replicates. The tree component, composed of the tree species M. urundeuva in the experimental density adopted, increased dry matter and crude protein of the forage mass harvest above stubble height, without affecting the concentration of neutral detergent fibre or acid detergent fibre, thus causing dry matter and organic matter in vitro degradability as well as effective degradability of the forage grass to remain the same as those obtained in full sun. Therefore, the results of this study show the possibility of using trees and grass to increase both animal production and environmental services.

Produtividade e valor nutritivo da

The aim of this study was to compare a silvopastoral system with a control (pasture only) in the Brazilian Cerrado. The silvopastoral system consisted of a tropical grass (Brachiaria brizantha cv. Marandu) pasture and trees (Zeyheria tuberculosa), while the control was a Marandu pasture without trees. Sheep intake, feeding behavior and microclimatic conditions were the variables evaluated. Temperatures within the silvopastoral system were lower than in the control (maximum temperature of 28 and 33.5 °C, temperature and humidity index of 74.0 and 79.2 for the silvopastoral system and control, respectively). There was increased dry matter intake (88.2 .05) in grazing sheep in the silvopastoral system relative to the control. The results suggest that a silvopastoral system would provide a more favorable environment than a straight pasture for sheep performance in a tropical grazing situation. ResumenEn el estudio se compararon un sistema silvopastoril con un sistema control de solo pastura en condiciones del Cerrado brasileño. El sistema silvopastoril consistió en una pastura de Brachiaria brizantha cv. Marandu con árboles de Zeyheria tuberculosa, mientras que el tratamiento control consistió en una pastura de cv. Marandu sin árboles. Como variables se midieron el consumo por ovejas, su comportamiento de pastoreo y las condiciones microclimáticas durante el tiempo de evaluaciones. Las temperaturas para el sistema silvopastoril fueron más bajas que en el control (temperatura máxima de 28 y 33.5 °C, e índice de temperatura-humedad de 74.0 y 79.2 para el sistema silvopastoril y el control, respectivamente). Las ovejas en pastoreo mostraron mayor consumo de materia seca (88.2 vs. 79.9 g MS/kg 0.75 peso vivo/día, P<0.05) y de materia orgánica (89.6 vs. 81.1 g MO/kg 0.75 peso vivo/día, P<0.05), mayor tiempo pastoreando (572 vs. 288 minutos/día, P<0.05), menor consumo total de agua (430 vs. 474 mL/kg 0.75 peso vivo/día, P<0.05) y menor tiempo caminando (30 vs. 89 minutos/día, P<0.05) en el sistema silvopastoril en comparación con el sistema control. Los resultados indican que para la producción ovina bajo condiciones tropicales un sistema silvopastoril puede proporcionar un entorno más favorable que un sistema de pastura sola.

No abstract

Neste estudo, foram utilizados fenos de Andropogon gayanus cv. Planaltina produzidos em diferentes idades de crescimento (56, 84, 112 e 140 dias) para ensaio de degradabilidade in vitro da matéria seca (DEIVMS), por meio da técnica in vitro semi-automática de produção de gases. Os dados de DEIVMS foram utilizados para confecção de equações que foram comparadas pelos testes de paralelismo e identidade de curvas. O teste de paralelismo não demonstrou diferença entre as equações e curvas, ou seja, as diferentes idades apresentaram o mesmo comportamento cinético de degradação. Contudo, pelo teste de identidade de curvas, observou-se que as equações e curvas dos fenos de A. gayanus colhidos com as plantas cortadas aos 56 e 84 dias são idênticas entre si, mas diferentes das demais, ou seja, apresentaram maior DEIVMS. Os fenos de A. gayanus nutricionalmente superiores são obtidos de plantas cortadas nos intervalos de 56 a 84 dias.

An increasing number of cases of infection and death by COVID-19 has been observed in several parts of the world, including Brazil. While scientists are looking for a drug / vaccine capable of combating COVID-19, its devastating action is spreading out of control. In this context, statistical studies and preliminary analyzes of the epidemic situation may be important to provide a basis for disease prevention and control. Thus, the objective of this work was to adjust nonlinear regression models to mortality data and confirmed cases of COVID-19 in Brazil, Italy and the world until 03/31/2020. Data from the Ministry of Health of Brazil and the World Health Organization were used. The models were compared using the Akaike information criterion and the Bayesian information criterion, as well as the determination and adjusted determination coefficients, in addition to the square root of the mean square error. All models presented were adequate to model the studied variables. It is not yet possible to make reliable projections of when the numbers of confirmed cases and deaths will decrease. Social detachment in Brazil is being effective in restricting the progression of the disease by reducing the speed of infection and transmissibility.

Mathematical models that describe gas production are widely used to estimate the rumen degradation digestibility and kinetics. The present study presents a method to generate models by combining existing models and to propose the von Bertalanffy-Gompertz two-compartment model based on this method. The proposed model was compared with the logistic two-compartment one to indicate which best describes the kinetic curve of gas production through the semi-automated in vitro technique from different pinto peanut cultivars. The data came from an experiment grown and harvested at the Far South Animal Sciences station (Essul) in Itabela, BA, Brazil and gas production was read at 2, 4, 6, 8, 10, 12, 14, 17, 20, 24, 28, 32, 48, 72, and 96 h after the start of the in vitro fermentation process. The parameters were estimated by the least squares method using the iterative Gauss-Newton process in the software R version 3.4.1. The best model to describe gas accumulation was based on the adjusted coefficient of determination, residual mean squares, mean absolute deviation, Akaike information criterion, and Bayesian information criterion. The von Bertalanffy-Gompertz two-compartment model had the best fit to describe the cumulative gas production over time according to the methodology and conditions of the present study.

The objective of this study was to evaluate the in situ degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and hemicellulose of elephant grass (Pennisetum purpureum, Schum.) with increasing levels (0; 35.0; 70.0, 105.0, and 140.0 g kg -1 ) of dried pineapple (Ananas comosus, L.) byproduct (DPBP). The experimental silos consisted of plastic drums with 210 L capacity. After weighing and homogenizing the elephant grass with the DPBP, the material was inserted in the silos (126 kg silage, at a density of 600 kg m -3 ) and compressed. After 45 days of ensilage, silos were opened and samples of the silages were collected for the trial. The study of degradability in situ was conducted using a rumen-fistulated steer. The animal was fed with corn silage supplemented with 1 kg concentrate daily. Five levels of addition of the byproduct were tested, with three replicates and five times of incubation with an animal. The experimental design was completely randomized with split plots, in which the proportions of DPBP were the treatments (plots), the different silos were the replicates, and the incubation times were the subplots. The levels of inclusion of DPBP provided an increase (P<0.05) in disappearance of DM and CP and in the effective degradability of DM, NDF, ADF and hemicellulose. The dried pineapple byproduct is a potential alternative to be used as additive in the ensilage of elephant grass, as it provides an increase in the rumen degradability parameters. Key words: Agroindustrial waste. Digestibility. In situ degradation. Intake. Rumen.