ABSTRACT: Short-term grazing behavior variables are sensitive to the canopy structure and have an impact on daily forage intake. This study evaluated the effect of pre- and post-grazing canopy heights on the forage harvesting process at a patch scale in a mixture of Brachiaria brizantha (Hochst. ex A. Rich.) Stapf. syn. Urochloa brizantha R.D. Webster cv. Marandu (palisade grass) and Arachis pintoi Krapov. & W.C. Greg. cv. Belomonte (forage peanut). Treatments were allocated to a split-plot arrangement in a completely randomized design. The plots, in their entirety, consisted of two pre-grazing canopy heights: 25 cm (CH25) and 35 cm (CH35); subplots consisted of three levels of defoliation severity: no defoliation (DS0); 20% depletion of pre-grazing canopy height (DS20); and 40% depletion of pre-grazing canopy height (DS40), with eight replications. Heifers were allowed to graze the patches (0.7 × 0.7 m) and their grazing behavior was recorded. Canopy structure measurements were taken both before and after grazing. Patches from CH35 presented greater stem mass for grass (p = 0.001) and legume (p = 0.002) than did patches from CH25. Bite rate, bite mass and instantaneous intake rate were greater for CH25 than for CH35 (p < 0.001, p = 0.068, and p = 0.074), and bite mass and instantaneous intake rate were lower for DS20 compared to DS0 (p = 0.032 and p = 0.016). Greater stem mass in the grazing strata negatively influenced the instantaneous intake rate.

Abstract Introduction: Reoperations in cardiac surgery represent a clinical challenge, particularly because of the higher rate of perioperative morbidity and mortality. Mitral valve reoperation owing to bioprosthesis dysfunction, transcatheter treatment with a prosthesis implantation over the prosthesis has emerged as an alternative, especially for patients with a previous approach. In this study, we analyzed the hydrodynamic behavior of transcatheter prosthesis implantation in conventional mitral bioprostheses through hydrodynamic tests and produced a recommendation for the size of transcatheter valve most adequate for valve-in-valve procedure. Methods: Mitral bioprostheses were attached to a flow duplicator and different combinations of transcatheter prostheses were implanted inside. The equipment simulates the hydrodynamic behavior of the valves submitted in vitro and determines transvalvular pressures and flow parameters. Results: All tests could be performed. Better hydrodynamic performance occurred for transcatheter prostheses 1 mm smaller than bioprostheses, except for the 27-mm bioprostheses. Effective valve areas (cm²) and transvalvular gradients (mmHg) were, respectively: Bioprosthesis × Inovare: 27 × 28 mm: 1.65 and 5.95/29 × 28 mm and 31 × 30 mm: 2.15 and 3.6. Conclusion: The mitral valve-in-valve implantation proved to be feasible in vitro. The use of 27-mm bioprostheses should be judicious, with preference for a 26-mm transcatheter valve. In the 29 and 31-mm bioprostheses, the implantation was very satisfactory, with good effective valve areas and transvalvular gradients, with preference for smaller transcatheter valves.

Resumo Embora o diagnóstico correto possa ser muitas vezes realizado pelo exame clínico, há várias situações em que os métodos de imagem representam a melhor opção para avaliar hérnias inguinais, seu conteúdo e eventuais complicações. Além disso, os abaulamentos da região inguinal nem sempre são hérnias, pois outras lesões como tumores, cistos e hematomas também acometem este sítio. O objetivo deste ensaio é demonstrar alguns diferentes conteúdos que podem ser diagnosticados no interior de hérnias inguinais. A diferenciação dos tipos de estruturas herniadas é de suma importância no planejamento do tratamento.

Abstract Although the correct diagnosis of inguinal hernias can often be made by clinical examination, there are several situations in which imaging methods represent the best option for evaluating such hernias, their content, and the possible complications. In addition, bulging of the inguinal region is not always indicative of a hernia, because other lesions, including tumors, cysts, and hematomas, also affect the region. The objective of this pictorial essay is to demonstrate what can be identified within inguinal hernias. Differentiating the types of herniated structures is of absolute importance for planning the appropriate treatment.

Resumo Disfunção das próteses biliares plásticas ou metálicas pode ser causada por migração, oclusão, mau posicionamento ou fratura. Uma prótese disfuncional na via biliar pode atuar como nidus causando complicações como colangite recorrente e persistente. Pode ainda causar complicações vasculares como formação de pseudoaneurismas ou sangramento, e além disso, perfurar a cápsula hepática causando biloma ou abscesso, ou raramente, causar obstrução intestinal e/ou perfuração. Demonstramos diferentes técnicas da radiologia intervencionista no tratamento de endopróteses biliares plásticas e metálicas disfuncionais, em pacientes com doença biliar obstrutiva.

Abstract Plastic and metal biliary stents can fail to function properly, such failure being due to a positioning error or to the migration, occlusion, or fracture of the stent. An obstructed biliary stent can act as a nidus, causing complications such as recurrent persistent cholangitis. It can also cause vascular complications (such as bleeding and the formation of pseudoaneurysms), perforate the liver capsule (causing biloma or abscess), or, in rare cases, cause intestinal obstruction or perforation. In this pictorial essay, we demonstrate various interventional radiology techniques for the treatment of biliary stent dysfunction in patients with obstructive biliary disease.

RESUMO A antecipação da aplicação de nitrogênio em sistemas de cultivo, usando plantas de cobertura, apresenta-se como alternativa para melhorar a eficiência do uso desse nutriente e otimizar a questão operacional. Objetivou-se com este trabalho, avaliar a eficiência da antecipação da adubação nitrogenada para a cultura do milho, tendo a braquiária como cultura de cobertura. O experimento foi conduzido na área experimental da Universidade Federal de Jataí, em Jataí - GO, com histórico de plantio em sucessão soja-milho/sorgo nos últimos 20 anos, e destaque para o teor de matéria orgânica do solo que é de 39,5 g kg-1. Utilizou-se delineamento de blocos ao acaso, com fatorial 5x2+1, com 4 repetições, sendo cinco doses de N: 0; 50; 100; 150 e 200 kg ha-1 e duas épocas de aplicação na cultura da braquiária, sendo a época 1: aplicação do nitrogênio 90 dias pré-semeadura do milho e época 2: aplicação do nitrogênio 60 dias pré-semeadura do milho e um tratamento adicional com adubação nitrogenada convencional de 150 kg ha-1 de nitrogênio, aplicada na cultura do milho, dividida em adubação de plantio e cobertura. Com exceção a dose de 200 kg ha-1 de N aplicada 90 dias antes da semeadura do milho, a antecipação da adubação nitrogenada para esta cultura, utilizando a braquiária como planta de cobertura, se mostrou tão eficiente quando a adubação convencional nas condições de solo e clima em que foi realizado o trabalho, ou seja, solo com alto teor de matéria orgânica, fertilidade construída e ausência de restrição hídrica.

ABSTRACT Advancing nitrogen (N) application in cropping systems, using cover crops, is an alternative to improve the efficiency of use of this nutrient and to optimize the operational issue. The aim of this study was to evaluate the efficiency of advancing N fertilization for corn crop, with Brachiaria ruziziensis as cover crop. The experiment was conducted at the experimental field of the Federal University of Jataí / Regional Unit of Jataí, GO, Brazil, with history of soybean-corn/sorghum succession in the last 20 years and a high organic matter content in the soil, which reaches 39.5 g kg-1. A randomized complete block design was used in a 5x2 + 1 factorial scheme with 4 replicates, corresponding to five N doses: 0; 50; 100; 150 and 200 kg ha-1 and two times of application in B. ruziziensis: Time 1 - N application 90 days before planting of corn, and Time 2 - N application 60 days before planting, plus an additional treatment with conventional N fertilization, 150 kg ha-1 of N, not advanced, applied to the corn crop, split into planting fertilization and top -dressing fertilization. Except for the N dose of 200 kg ha-1 applied 90 days before corn sowing, advancing N fertilization for this crop using B. ruziziensis as cover plant proved to be as efficient as conventional fertilization for the soil and climate conditions under which the study was carried out, that is, soil with high content of organic matter, built fertility and absence of water restriction.

ABSTRACT Insect damage to stored seeds is a challenge. Rhyzopertha dominica (Fabricius, 1792) (Coleoptera: Bostrichidae) is a major pest of seeds and grains in the world, but without record in seeds of the sudangrass (Sorghum drummondii (Poaceae)). The objective of this work was to report, for the first time, the occurrence and damage by R. dominica in S. drummondii seeds, sold in sealed packages in retail market. Four samples with 500 seeds each and without adult insects were separated from a package. The initial weight was obtained with a precision scale and the seeds were stored. The number of adult insects, the weight loss and the infestation rate of the seeds were evaluated 60 days later and the average between samples used to extrapolate the damage per package. An adult of R. dominica, on average, was obtained for each seven seeds and 54.06% of the seeds were damaged, with an average weight loss of 36.09%. This is the first report of R. dominica in sudangrass seeds and the damage inflicted shows that this insect may cause losses in the quantity and quality of seeds due to its rapid populational growth.

Resumo Objetivo: Avaliar lesões hepáticas de acordo com a classificação LI-RADS nas tomografias computadorizadas de pacientes com hepatite B, co-infectados ou não com vírus delta, e com hepatite C crõnica, e o grau de concordância entre os radiologistas. Materiais e Métodos: Foram incluídos 38 pacientes com hepatite B, co-infectados ou não com vírus delta, e/ou com hepatite C crônica, que realizaram tomografia computadorizada. Dois radiologistas selecionaram até três lesões hepáticas classificadas pelo LI-RADS e avaliaram sinais de hepatopatia crônica e de hipertensão portal. Foi utilizado o teste kappa (κ) para avaliar o grau de concordância entre os radiologistas. Resultados: Foram selecionadas 56 observações pelo radiologista 1 e 48 pelo radiologista 2. Verificou-se que 71% e 61% dos pacientes apresentaram pelo menos uma observação hepática, segundo o radiologista 1 e o radiologista 2, respectivamente. Dos 38 pacientes, 13 (34%), segundo o radiologista 1, e 12 (32%), segundo o radiologista 2, apresentaram observações LI-RADS 5 (κ = 0,821). Hipervascularização foi detectada em 50% e 42% dos pacientes (κ = 0,668), esplenomegalia em 79% e 63% (κ = 0,503) e sinais de hepatopatia crônica em 82% (κ = 1,00), segundo o radiologista 1 e o radiologista 2, respectivamente. Conclusão: Detectaram-se, aproximadamente, 32% de observações LI-RADS 5 nos pacientes, com concordância quase perfeita entre os radiologistas. Houve concordância substancial/moderada entre as demais categorias LI-RADS.

Abstract Objective: To evaluate liver lesions, in accordance with the LI-RADS classification, using contrast-enhanced multiphase dynamic computed tomography in patients with hepatitis B, coinfected or not with hepatitis D, or with chronic hepatitis C, as well as to determine the level of agreement between radiologists. Materials and Methods: We evaluated 38 patients with hepatitis B, coinfected or not with hepatitis D, or with chronic hepatitis C, all of whom underwent contrast-enhanced multiphase dynamic computed tomography. For each examination, two radiologists selected up to three hepatic lesions, categorizing them in accordance with the LI-RADS classification and evaluating signs of chronic liver disease and portal hypertension. To determine the level of agreement between radiologists, we calculated the kappa statistic (κ) . Results: Radiologist 1 and radiologist 2 selected 56 and 48 liver lesions, respectively. According to radiologist 1 and radiologist 2, respectively, 27 (71%) and 23 (61%) of the 38 patients had at least one liver lesion; 13 (34%) and 12 (32%) had a LI-RADS 5 lesion (κ = 0.821); 19 (50%) and 16 (42%) had a hypervascular lesion (κ = 0.668); and 30 (79%) and 24 (63%) had splenomegaly (κ = 0.503). Both radiologists identified chronic liver disease in 31 (82%) of the patients (κ = 1.00). Conclusion: Lesions categorized as LI-RADS 5 were detected in approximately 32% of the patients, with almost perfect agreement between the radiologists. The level of agreement was substantial or moderate for the other LI-RADS categories.

Abstract The essential oils obtained by hydrodistillation from fresh leaves of Vitex agnus-castus and Ocimum campechianum, and from fresh inflorescences of Ocimum carnosum were analysed by GC-FID and GC-MS. The major components of V. agnus-castus essential oil were identified as 1,8-cineole (47.9%), terpinyl α-acetate (11.6%), sabinene (11.2%) and caryophyllene oxide (9.7%), while in the O. campechianum essential oil were eugenol (72.1%), β-elemene (6.8%), (E)-caryophyllene (6.4%) and bicyclogermacrene (5.2%). Linalool (79.0%), α-epi-cadinol (5.4%), terpinen-4-ol (3.2%) and 1,8-cineole (2.8%) were the major constituents in the O. carnosum essential oil. The essential oils were subsequently evaluated for their larvicidal and cytotoxic activities. Larval bioassay against Aedes aegypti of V. agnus-castus, O. campechianum and O. carnosum essential oils showed LC50 values of 97.55 ± 0.35, 81.45 ± 0.35 and 109.49 ± 0.35 μg/mL, respectively. The in vitro cytotoxic activities of the essential oils has been evaluated on breast adenocarcinoma (MCF-7), lung carcinoma (NCI-H292), pro-myelocytic leukemia (HL-60), and cervical adenocarcinoma (HEP-2) human cell lines, and pro-myelocytic leukemia cells lines (HL-60) were found to be the most sensitive to all the essential oils tested than the others. This is the first report on larvicidal and cytotoxic activities of these essential oils.

ABSTRACT. The aim of this study was to evaluate the addition of macauba palm cake (Acrocomia aculeata) on the chemical composition, fermentation and aerobic stability of elephant grass silages (Pennisetum purpureum). The experiment was performed in a completely randomized design with four replicates. The treatments were composed of six levels of macauba palm cake (0, 6, 12, 18, 24, 30%) as additive to elephant grass silage. Dry matter and ethereal extract content of the silage increased linearly with the inclusion of the additive. Addition levels of 15.54% would provide 35% of dry mass, and the limit of 7.00% of ethereal extract in the silage could be obtained with 10.47%. The neutral detergent fiber content reduced linearly from 68.97 to 52.59%, but lignin increased linearly from 6.56 to 7.70%. There was a reduction of 0.17% in the ammoniacal nitrogen content for each 1% of cake. The minimum value of dry matter losses (1.33%) was estimated to the inclusion level of 23.70%. The aerobic stability increased with inclusions between 18 and 24% of cake. The use of levels between 10 and 15% of macauba palm cake are sufficient to optimize dry matter and ethereal extract contents of the silages and to provide a high aerobic stability with minimum losses.

ABSTRACT. Herbicides have been used to control Brachiaria grass in pastures established or in formation given their practicality, however their efficiency is questionable due to the lack of specific graminicides for different forage species. Therefore, the goal of this study was to evaluate the efficiency of glyphosate and fluazifop-p-butyl in the control of Brachiaria decumbens (signalgrass) and the intoxication levels of Panicum maximum cv. Tanzania (Tanzania quinea grass) in pasture establishment. The experiments were designed in randomized blocks, in a 2 × 5 × 4 factorial arrangement of two herbicides (fluazifop-p-butyl and glyphosate), five doses equivalent to the commercial dosage of each herbicide (0.25; 0.50; 1.00; 1.50; 200), and four evaluation times after herbicide application (15, 21, 30 and 45 days). There was interaction between doses and evaluation times. The dose 1.5 L ha-1 fluazifop-p-butyl provides efficient control of signalgrass, however, leads to high intoxication in Tanzania guinea grass. Glyphosate is efficient in the control of signalgrass even at the lowest dose (90 g ha-1), however, it causes high intoxication in Tanzania guinea grass, preventing its use in developing pastures. It can be concluded that fluazifop-p-butyl and glyphosate herbicides are not recommended for the control of B. decumbens, cv. Basilisk in developing pastures of Tanzania guinea grass.

ABSTRACT In experiments with selection of perennial plants, the initial performance is expected to be maintained throughout the productive life. The probability of repeating the agronomic response can be evaluated by the repeatability coefficient. The objective was to estimate repeatability coefficients of agronomic characteristics in Panicum maximum Jacq. using different methods and identify the best combinations between harvests according to the genotypic stabilization. Seventeen genotypes were evaluated in a randomized complete block design with three replicates. The coefficients of repeatability were estimated by the methods: ANOVA, structural analysis based on the mean of the correlation coefficients (SACOR), analysis of principal components based on the covariance matrix (PCCOV) and correlation matrix (PCCOR). In the genotypic stabilization, coefficients estimated by ANOVA and PCCOR were used. For total DM, repeatability coefficients ranged from 0.3500 to 0.4300 by the ANOVA and PCCOR methods, respectively. High repeatability coefficients were found for the characteristic leaf DM, while low coefficients were observed for leaf and stem percentages and leaf:stem ratio. For the genotypic stabilization of total DM and leaf:stem ratio, the best coefficients were observed for the combination of harvests 5 to 8. There are variations in the estimate of repeatability by different methods and the highest coefficients were those of the principal components based on the correlation and covariance matrices. For the genotypic stabilization, the best coefficients of repeatability and determination were observed for the harvests performed in the second rainy period.

Resumo Stuart Hall, um acadêmico fundador da Escola de Birmingham de estudos culturais e eminente teórico de etnia, identidade e diferença na diáspora africana, bem como um dos principais analistas da política cultural dos anos Thatcher e pós-Thatcher, realizou as Palestras W. E. B. Du Bois na Universidade de Harvard em 1994. Nas palestras, publicadas após um atraso de quase um quarto de século como The Fateful Triangle: Race, Ethnicity, Nation (2017), Hall avança o argumento de que a raça, pelo menos nos contextos do Atlântico Norte, funciona como um ‘significante escorregadio,’ de modo que, mesmo depois que a noção de uma essência biológica para a raça tenha sido amplamente desacreditada, o raciocínio racial, no entanto, se renova ao essencializar outras características, como a diferença cultural. Substituindo a famosa díade de Michel Foucault com conhecimento-poder-diferença, Hall argumenta que pensar através do triângulo fatídico da raça, etnia e nação nos mostra como os sistemas discursivos tentam lidar com a diferença humana. Em ‘Triângulos Fatídicos no Brasil’, Parte II do Fórum da Contexto Internacional sobre The Fateful Triangle, três acadêmicos trabalham com e contra os argumentos de Hall do ponto de vista da política racial no Brasil. Sharon Stanley argumenta que a abordagem de Hall da identidade híbrida pode encontrar dificuldades no contexto brasileiro, onde os discursos de mistura racial têm, em nome da democracia racial, apoiado o racismo anti-negro. João Nackle Urt investiga as conturbadas histórias de ‘raça,’ ‘etnia’ e ‘nação’ em referência aos povos indígenas, particularmente os índios brasileiros. Por fim, Thiago Braz mostra, a partir de uma perspectiva que se baseia em pensadores afro-brasileiros, que enfatizar a contingência no conceito de diáspora pode ignorar a miríade de maneiras pelas quais brasileiros afro-diaspóricos são marcados como negros e, portanto, sujeitos à violência e desigualdade. A Parte I do fórum – com contribuições de Donna Jones, Kevin Bruyneel e William Garcia – examina criticamente as promessas e potenciais problemas do trabalho de Hall no contexto da América do Norte e da Europa Ocidental, na esteira do #BlackLivesMatter e Brexit.

Abstract Stuart Hall, a founding scholar in the Birmingham School of cultural studies and eminent theorist of ethnicity, identity and difference in the African diaspora, as well as a leading analyst of the cultural politics of the Thatcher and post-Thatcher years, delivered the W. E. B. Du Bois Lectures at Harvard University in 1994. In the lectures, published after a nearly quarter-century delay as The Fateful Triangle: Race, Ethnicity, Nation (2017), Hall advances the argument that race, at least in North Atlantic contexts, operates as a ‘sliding signifier,’ such that, even after the notion of a biological essence to race has been widely discredited, race-thinking nonetheless renews itself by essentializing other characteristics such as cultural difference. Substituting Michel Foucault’s famous power-knowledge dyad with power-knowledge-difference, Hall argues that thinking through the fateful triangle of race, ethnicity and nation shows us how discursive systems attempt to deal with human difference. In ‘Fateful Triangles in Brazil,’ Part II of Contexto Internacional’s forum on The Fateful Triangle, three scholars work with and against Hall’s arguments from the standpoint of racial politics in Brazil. Sharon Stanley argues that Hall’s account of hybrid identity may encounter difficulties in the Brazilian context, where discourses of racial mixture have, in the name of racial democracy, supported anti-black racism. João Nackle Urt investigates the vexed histories of ‘race,’ ‘ethnicity’ and ‘nation’ in reference to indigenous peoples, particularly Brazilian Indians. Finally, Thiago Braz shows, from a perspective that draws on Afro-Brazilian thinkers, that emphasizing the contingency of becoming in the concept of diaspora may ignore the myriad ways by which Afro-diasporic Brazilians are marked as being black, and thus subject to violence and inequality. Part I of the forum – with contributions by Donna Jones, Kevin Bruyneel and William Garcia – critically examines the promise and potential problems of Hall’s work from the context of North America and western Europe in the wake of #BlackLivesMatter and Brexit.

Objetivou-se com esta pesquisa avaliar a resposta produtiva e os ciclos de colheita do capim-marandu irrigado e adubado com combinações contendo ureia e esterco bovino em diferentes períodos. Utilizou-se delineamento em blocos casualizados, em esquema de parcelas subdivididas no tempo com 5 tratamentos e 5 repetições. Foram testados cinco níveis de substituição da ureia por esterco bovino (0; 25; 50; 75 e 100% de esterco bovino) em três épocas de crescimento. O acúmulo de forragem total e de folhas com a inclusão do esterco em substituição a ureia reduziu em 59,24% e 61,23%, respectivamente. A produção acumulada e o número de ciclos de colheita decresceram com a inclusão de esterco bovino, de 44,7% e 46,66% respectivamente. As porcentagens de folha, colmo e morto foram influenciadas somente pela época, sendo os melhores resultados observados no segundo período. A produção acumulada e o número de ciclos de colheita decresceram com a inclusão de esterco bovino. A produção de forragem e os ciclos de colheita são afetados negativamente pela inclusão do esterco em substituição à ureia.

The objective of this work was to evaluate the productive response and harvest cycles of irrigated and fertilized marandu grass with combinations containing urea and bovine manure in different periods. A randomized complete block design was used, in a plot scheme subdivided in time with 5 treatments and 5 replications. Five levels of urea replacement by bovine manure (0, 25, 50, 75 and 100% bovine manure) were tested at three growing seasons. The accumulation of forage and leaves with the inclusion of manure in substitution of urea decreased by 59.24% and 61.23%, respectively. The accumulated production and the number of harvest cycles decreased with the inclusion of bovine manure, 44.7% and 46.66%, respectively. The percentages of leaf, stem and dead were influenced only by the season, and the best results were observed in the second period. The accumulated production and the number of harvest cycles decreased with the inclusion of bovine manure. Forage production and harvest cycles are negatively affected by the inclusion of manure as a substitute for urea.

RESUMO Com o avanço da idade de corte, há aumento na produtividade da forragem de capim-elefante (Pennisetum purpureum), mas, também, redução nos teores de proteína e digestibilidade da forrageira. Objetivou-se determinar a época ideal de corte da forragem em capim-elefante (cultivar BRS Canará), para a produção de feno picado. Utilizou-se delineamento experimental em blocos casualizados, com cinco tratamentos (42, 60, 76, 91 e 105 dias de crescimento) e quatro repetições. Foram avaliadas características agronômicas, morfológicas e químicas. Verificou-se efeito linear positivo do momento de colheita sobre a altura da planta, material senescente e produtividade do feno picado. Já a porcentagem de lâminas foliares e a relação folha:colmo reduziram-se, em função da idade de corte. A idade de corte também exerceu efeito linear positivo sobre a fibra em detergente neutro indigestível, fibra em detergente neutro corrigida para cinzas e proteína e proteína insolúvel em detergente neutro, com aumentos de 17,13 %, 16,63 % e 20,66 %, respectivamente. Já os teores de cinzas, proteína bruta, nutrientes digestíveis totais e energia líquida de lactação diminuíram com o avanço da idade da forrageira. A partir de 76 dias, os teores de cinzas atingiram valores abaixo de 9,29 % e a proteína bruta abaixo de 7,16 %. Nesta idade de corte, a produtividade de feno foi de 12,91 t ha-1. Para melhorar a qualidade e a produção de feno, a cultivar BRS Canará deve ser cortada entre 60 e 76 dias, quando as plantas estão com 1,20-1,50 m de altura, relação folha:colmo de 0,55-0,44, proteína bruta de 8,29-7,16 % e fibra em detergente neutro indigestível de 26,21-29,06 %.

ABSTRACT With the advancement of the cutting age, there is an increase in the forage yield of elephant grass (Pennisetum purpureum), but there is also a reduction of the protein levels and digestibility of this forage. This study aimed to identify the ideal cutting age of elephant grass forage (BRS Canará cultivar) to chopped hay production. The experimental design was a randomized block, with five treatments (42, 60, 76, 91 and 105 days of growing) and four replicates. Forage agronomical, morphological and chemical characteristics were evaluated. A linear positive effect of the cutting age was observed on plant height, senescent material and yield of the chopped hay. The leaf percentage and leaf:stem ratio were reduced by the advance in the cutting age. There was also a linear positive effect of the cutting ages on indigestible neutral detergent fiber, neutral detergent fiber corrected for ash and protein and neutral detergent insoluble protein, with increases of 17.13 %, 16.63 % and 20.66 %, respectively. The contents of ashes, crude protein, total digestible nutrients and net lactation energy were reduced with the advance in the forage age. From 76 days, the ashes contents reached values below 9.29 % and the crude protein below 7.16 %. In the same cutting age, the chopped hay yield was 12.91 t ha-1. To improve the hay quality and production, the BRS Canará cultivar must be harvest between 60 and 76 days, when the plants are with 1.20-1.50 m of height, leaf:stem ratio of 0.55-0.44, crude protein of 8.29-7.16 % and indigestible neutral detergent fiber of 26.21-29.06 %.

RESUMO : O uso de Sarcoptes scabiei como microrganismo teste para bioensaio in vitro é um método de estudo viável para diversas drogas acaricidas. Muitos ensaios comprovam a diversidade e eficiência de atividade biocida de extratos e componentes presentes em plantas do cerrado brasileiro. Este trabalho objetivou testar e comparar a atividade acaricida de quatro bioprodutos do cerrado brasileiro: Stryphnodendron adstringens Mart., Lafoensia pacari A. St Hil., Copaifera sp. e Pterodon emarginatus Vogel, 1837. Para este estudo, ácaros S. scabiei foram colhidos em crostas removidas de orelhas de fêmeas suínas altamente infestadas. Os ácaros foram selecionados, separados e colocados em placas de Petri com três diferentes concentrações (25, 50 e 75%) de bioprodutos, para avaliar o potencial de atividade acaricida de cada um. Foi realizada a contagem da mortalidade dos ácaros em cada placa de Petri a cada hora, durante cinco horas. As análises estatísticas demonstraram diferenças entre os bioprodutos testados. As óleo-resinas de Copaifera sp. e P. emarginatus apresentaram os melhores resultados, com 100% de mortalidade dos ácaros após tratamento. Os extratos etanólicos de S. adstringens Mart. e L. pacari demonstraram menor atividade acaricida quando comparados as óleo-resinas, com pequena ou nenhuma diferença entre os resultados dos grupos controle. Este ensaio demonstrou ser uma ferramenta eficiente, confiável, de baixo custo e de fácil realização. As óleo-resinas Copaifera sp. e P. emarginatus possuem atividade acaricida in vitro sobre fêmeas adultas de S. scabiei var. suis.

ABSTRACT: In vitro bioassay using Sarcoptes scabiei as a test microorganism is a viable method of study for diverse drugs with acaricidal properties. A great amount of assays proves the diverse and efficient biological activity of extracts and compounds from Brazilian savanna plants. This study had as main object, test and compare the acaricidal activity of four Brazilian Cerrado bioproducts: Stryphnodendron adstringens Mart., Copaifera sp., Lafoensia pacari A. St Hil. and Pterodon emarginatus Vogel, 1837. To perform this test S. scabiei mites were collected from crusts removed on ears of highly infected sows. The mites were selected and separated in Petri dishes with three different concentrations (25, 50 and 75%) of each bioproduct, to evaluate their potential acaricidal activity. The mortality of the mites was counted in each Petri dish every hour, during five hours. The statistical analyses demonstrated differences between the bioproducts tested. The oleoresin of Copaifera sp. and P. emarginatus presented the best results with 100% of mites mortality after treatment. The ethanolic extracts of S. adstringens and L. pacari demonstrated lower acaricidal activity when compared to the oleoresins, with little or no difference among the control groups tested. This bioassay demonstrated to be efficient, reliable, low cost and easy accomplishment. Oil resins from Copaifera sp. and P. emarginatus have in vitro acaricidal activity against adult females of S. scabiei var. suis.