Agricultural Research Company Research Articles

Effect of the climatic environment on ingestive behavior of F1 Holstein x Zebu cows

SUMMARY The objective of this study was to evaluate the ingestive behavior of five different genetic groups of F1 Holstein x Zebu (HxZ) cows during lactation during the summer. The evaluated groups were: Holstein x Gir, Holstein x Nelogir, Holstein x Guzonel, Holstein x Nelore and x Indubrasil. The experiment it occurred place during the summer in the Farm of Agricultural Research Company of Minas Gerais, located in Felixlândia- MG. A completely randomized design with factorial arrangement 5 × 4, five crossings and four periods of observation, with ten repetitions was used. The measurements of climate variables were made using dataloggers and calculated the black globe temperature and humidity index. There was the percentage of animals grazing, rumination, urination, defecation, water intake and salt intake during the day and at night every 30 minutes. The F1 animals used did not affect the grazing behavior due to high BGT values. There was a higher frequency of rumination and idle period in the morning, showing a natural behavior of cattle. Defecation was higher during the day, coinciding with the period of greater movement of animals. Water consumption was greater in the post- milking and the salt consumption in the afternoon. There was a positive statistical correlation between BGT and grazing, and negative correlation between BGT and leisure. Thus, the F1 animals grazing behavior has not changed because of the high BGT values, explaining the adaptability and resilience of five genetic groups, being a viable option for warm climate regions.

Gestão da Inovação na Embrapa Mandioca e Fruticultura: Uma Aproximação ao Planejamento Estratégico

Due to the importance of innovation in companies, and especially in the Brazilian Agricultural Research Company - EMBRAPA, this article sought to portray a case study in Embrapa Mandioca and Fruticultura in response to the expectations created about innovation in its strategic planning, in the period of 2008-2014. The article verified how the model of innovation management is structured and organized, as well as the perception of employees regarding the model used. In this context, the work was divided into five chapters: introduction, addressing the purpose of the proposal; A review of the literature, dealing with strategic management and innovation management; The methodology, contextualizing the format of the research; And the results and discussions, where a diagnosis of the current situation of Embrapa Mandioca and Fruticultura regarding innovation was obtained, creating an expectation that this research contributes effectively to the management of the Unit and, consequently, promotes improvements in its planning strategic.

Comportamento de cultivares de cafeeiro sob a incidência das doenças da ferrugem e cercosporiose em dois ambientes de cultivo

A ferrugem-alaranjada causada por Hemileia vastatrix é a principal doença da cafeicultura em abrangência e danos. O desenvolvimento de cultivares resistentes e/ou tolerantes às pragas e doenças tem papel importante no aumento de produtividade e diminuição de custos de produção. Dessa forma, objetivou-se com este trabalho disponibilizar informações da reação à ferrugem e cercosporiose de dez cultivares comerciais de Coffea arabica em duas importantes regiões cafeeiras de Minas Gerais. Os experimentos foram conduzidos em duas importantes regiões cafeeiras do estado de Minas Gerais (Sul de Minas e Alto Paranaíba), sendo implantados em áreas experimentais públicas, na Fazenda Experimental da Empresa de Pesquisa Agropecuária de Minas Gerais (Epamig), em Patrocínio-MG e no Campus Experimental da Universidade Federal de Lavras (Ufla), em Lavras-MG. O delineamento experimental utilizado foi o de blocos casualizados, com três repetições, com parcelas de 10 plantas, tendo sido considerada como parcela útil apenas as seis plantas centrais. O espaçamento adotado foi de 3,5m entre linhas x 0,70 m entre plantas. As avaliações da incidência e severidade da ferrugem e incidência de cercosporiose foram realizadas mensalmente, nos meses de janeiro a agosto de cada ano (safras 2011/2012 e 2012/2013). Os percentuais de incidência das doenças foram transformados em área abaixo da curva de progresso da incidência e severidade da ferrugem (AACPIF, AACPSF) e incidência da cercosporiose (AACPIC), de acordo com critérios estabelecidos por Campbell e Madden (1990). A cultivar Oeiras apresenta perda total de resistência à ferrugem, a cultivar Catiguá MG2 apresenta imunidade ao patógeno da ferrugem e as cultivares em estudo não apresentam resistência à cercosporiose.

High levels of benzimidazole resistance and β-tubulin isotype 1 SNP F167Y in Haemonchus contortus populations from Ceará State, Brazil

Haemonchus contortus is the most prevalent parasitic nematode in tropical areas, and anthelmintic resistance is a global problem. Our objective was to characterize benzimidazole (BZ) resistance in gastrointestinal nematode populations in Ceará State, Brazil, using the egg hatch test (EHT) and in H. contortus populations using quantitative real-time polymerase chain reaction (qPCR). Twenty locations were surveyed, and fecal samples were collected from a minimum of 40 animals from each farm and pooled. Five thousand L3 from each farm were used to infect single animals at Embrapa (Brazilian Agricultural Research Company) to provide a source of eggs for both phenotypical and molecular tests. The mean EHT was 2.46μg/ml (±0.58μg/ml), and BZ resistance was detected at all surveyed locations. The mean resistant allelic frequencies at positions F200Y and F167Y were 34.16% (±12.13%) and 58.31% (±18.89%), respectively. The resistant allelic frequencies at F167Y were higher than those at F200Y in most studied locations. We also investigated the possibility that specific BZ utilization may influence resistant allelic frequencies. We selected three nematode populations based on the resistant SNP prevalence at F200Y and F167Y as follows: higher frequency at SNP F200Y, higher frequency at SNP F167Y and similar frequencies at both positions. Anthelmintic treatments included two BZs (oxfendazole and albendazole) and ivermectin. Three animals per population per treatment were infected with 5000 L3, and nematode eggs were collected for molecular test before and after anthelmintic treatments. The results showed preferential selection of SNP F167Y in response to oxfendazole, an increase in resistant SNP frequencies in general in response to albendazole and little change in relation to pre-treatment situations in response to ivermectin. Our results confirm that BZ resistance is common. The resistant allele at SNP F167Y in H. contortus prevails in Ceará State, and we provide evidence that this result may be due to the utilization of oxfendazole in recent years.

Maturation evolution of chardonnay grape for juice preparation

This study aims to evaluate the evolution of the maturation of the “Chardonnay” grape variety for the preparation of juices and its adequacy to the current legislation. Grapes from the 2015 harvest from Sao Lourenco do Sul-RS were used. The experimental design was completely randomized in a factorial design, with the treatment factor being the maturation stages. The physicochemical analysis of titratable acidity, soluble solids, relative density, total sugar, alcohol content, volatile acidity and SS/TA ratio were carried out in EPAGRI – Agricultural Research and Rural Extension Company of Santa Catarina, in the Videira Experimental Station (Videira SC/Brazil). Statistical analysis of the maturation stages was given by linear regression models. When comparing the maturation points of 17∘ Brix and 19∘ Brix to 15∘ Brix, volatile acidity and alcohol content did not fit to the model, while the other tested variables fit properly. Elaborated juices had a decrease in titratable acidity and percentage increments for soluble solids, SS/TA ratio and total sugars for the harvest points at 17 and 19∘ Brix. For 15∘ Brix and 17∘ Brix, nonconformity was observed with the identity and quality standards in relation to soluble solids and SS/TA ratio and relative density. At maturation point 19∘ Brix all variables were found to be consistent.

Tomato yield and quality under various combinations of organic compost

The number of growers and planted area dedicated to organic farming have increased considerably. Consequently, demand has increased for alternative organic composts in terms of quantity and new options for direct use with crops. Making use of local industrial byproducts is also important throughout Brazil and the rest of the world. Therefore, it was evaluated the effect of eight types of organic composts, produced with different percentages of poultry litter and crushed sugarcane on tomato yield and quality. The experiment was carried out during the 2013 growing season at the experimental farm of the Agricultural Research Company of Minas Gerais state ( Empresa de Pesquisa Agropecuaria do Estado de Minas Gerais ) located in Prudente de Morais, MG, Brazil. It was evaluated different formulations of poultry litter and crushed sugarcane (0, 10, 20, 30, 40, 50, 50, 60 and 70%) yielding eight types of alternative Bokashi used as organic compost in the production of two tomato cultivars (Santa Clara and the Verano hybrid). It was found that the various formulations of alternative Bokashi, except the alternative Bokashi B1, strengthened components of tomato yield and quality. We found that composts of poultry litter and crushed sugarcane increase tomato yield and quality and can be and excellent alternative, especially for organic farmers.

Technology Transfer Model Proposal in Public Research Institutions: The Search for a more Effective Process in the Broiler Chain in Brazil

Brazilian agricultural and livestock represent 22.54% of the Brazilian Gross Domestic Product. The Brazilian Agricultural and Livestock Research Company aims to develop technologic solutions for this sector. It has an approximate annual budget of 2.5 million dollars and 2,440 researchers. The researches target audience diversity makes more challenging the Technology Transfer process for the institution. The objective of this article was the proposal and validation, under the perception of the broiler productive chain agents, of a Technology Transfer model to optimize the public-private interaction for the institution. Were interviewed 142 agents, with a statistically significant sample, higher than 95%. The results demonstrated the contribution of Embrapa for the technological development of the chain is perceived as low, but the Technology Transfer model presented was considered essential by 96.77% of the respondents to optimize the Technology Transfer of Embrapa Pigs and Poultry to the chain.

Notes on technological changes in the production and agribusiness poultry in the region of AMREC, Santa Catarina State, Brazil.

The study of agricultural and agro-industrial activities in areas with diversified economy is relevant because of the impact of this production in the local development. In this study we develop a research, on the theme of innovation (technological change) in agricultural and agro-industrial activities, focusing on the poultry production in the counties of AMREC region, southern of Santa Catarina State, Brazil. The research was conducted in 2013 and had a qualitative approach. We carried out: a) literature review on the subject, b) field research to collect information from the exhibitors in an agricultural fair (Agroponte) and with researcher from CIDASC, the agricultural development company of Santa Catarina State, and c) a survey in documents available from EPAGRI, the state agricultural research company. The study results indicate that the growth of poultry production in the region has attracted the attention of some companies. However, it was observed that these companies are offering the same machinery (product range) offered elsewhere and conventional technology solutions.

Beekeeping and Agroecological Systems for Endogenous Sustainable Development

This article examines the process of agroecological research on beekeeping systems, developed jointly by the Temperate Agriculture Program of the Brazilian Agricultural Research Company (EMBRAPA), and the Institute of Sociology and Peasant Studies (ISEC), of the University of Córdoba. The investigation was carried out on different beekeeping experiences in southern Brazil: peasant family farms, settlements of agrarian reform, and Afro-descent quilombola and Guarani indigenous villages. The systems are managed in the contexts of agroecological farming and include “Africanized honeybees” and native “stingless bees,” integrated among trees and crops. We show that the dynamics of investigation that follows the guidelines presented by family farmers and traditional people contribute to their empowerment and to changing their own reality, favoring endogenous development and the dialogue of knowledge. The participatory experiences by ISEC and EMBRAPA Temperate Agriculture through the organization and mobilization of farmers and traditional people generated organizational structures that build local food systems. This joint initiative contributes to peasants’ search for autonomy and food sovereignty, and strengthens the reproduction of this work toward the political dimension of agroecology.

Efeito da idade de aquisição de fêmeas de reposição na rentabilidade da atividade leiteira

Analisou-se, por meio de simulação, o efeito da idade de aquisição de fêmeas para reposição na rentabilidade de um sistema de produção de leite com vacas F1 Holandês x Gir, no período de 01 de maio de 2011 a 30 de abril de 2012. Durante o período chuvoso, na época do verão, as vacas foram mantidas em pastos e, durante o período da seca, foram confinadas com o uso da cana-de-açúcar in natura enriquecida com ureia e sulfato de amônio. A referência zootécnica foi do rebanho da Fazenda Experimental de Felixlândia (FEFX) da Empresa de Pesquisa Agropecuária de Minas Gerais (EPAMIG), localizada no município de Felixlândia, MG. O inventário, bem como as despesas, as receitas e os demais dados, foram cadastrados no software CUSTO BOVINO LEITE 1.0, visando obter a análise de rentabilidade. Tal software contempla as metodologias de custo total de produção (clásssica), que envolve o custo fixo e variável, e custo operacional. A aquisição da fêmea de reposição, aos 10 ou aos 30 meses de idade, é rentável para o sistema de produção de leite analisado. Como alternativa mercadológica, a aquisição da fêmea de reposição com 10 meses de idade foi a pior opção, devido ao alto valor de aquisição e devido a necessidade da aquisição de maior quantidade de fêmeas, em função da taxa de mortalidade.

Características físico-químicas de cultivares de macieiras pouco exigentes em frio

O sul do Brasil é a região brasileira com mais tradição na produção de maçãs. Contudo, novos cultivares menos exigentes em frio estão viabilizando os cultivos em outras regiões do Brasil, como no Estado de Minas Gerais, onde a cultura encontra-se em franca expansão. Os atributos físico-químicos dos frutos são importantes, tanto para a industrialização, quanto para o consumo dos frutos in natura. Neste sentido, objetivou-se, com este trabalho, realizar a caracterização físico-química de maçãs de oito cultivares, pertencentes à coleção estabelecida na Serra da Mantiqueira, sul de Minas Gerais. O experimento foi conduzido em pomar experimental, na Empresa de Pesquisa Agropecuária de Minas Gerais EPAMIG, na cidade de Maria da Fé, sul de Minas Gerais. Foram analisados frutos de macieira de oito cultivares (Michal, Ein Shemer, Soberana, Galícia, Eva, IAC 2079, Condessa e Anna) oriundos de plantas com seis anos de idade. Foram avaliados: massa do fruto, diâmetro transversal, diâmetro longitudinal, firmeza de frutos, acidez titulável (AT), sólidos solúveis (SS), relação SS/AT, pH e produção de frutos. Os cultivares 'Anna' e 'Condessa' produziram os maiores frutos; 'Eva' apresentou maior produção e frutos mais firmes; 'Anna', os mais macios; enquanto 'Galícia' e 'IAC 2079,' os de sabor mais equilibrado.

Efeito da inversão no tratamento de moirões submetidos ao método de substituição da seiva

http://dx.doi.org/10.5902/1980509813338O objetivo da pesquisa foi avaliar o efeito da inversão de moirões de algaroba (Prosopis juliflora) e de leucena (Leucaena leucocephala), na solução preservativa, na distribuição, penetração e retenção do borato de cobre cromatado (CCB) aplicado pelo método de substituição da seiva. A algaroba foi coletada na Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) e a leucena no Campus da Universidade Federal de Campina Grande, em Patos - PB. Foram colhidas árvores com DAP entre 6,0 a 12,0 cm. Retiraram-se dois discos de 2,0 cm de espessura no topo e base das peças. Os discos externos foram descartados e os internos empregados nas determinações das características das madeiras, ficando as peças com 2,0 m. Empregou-se uma solução de 2% de ingredientes ativos de CCB. Foram tratadas 10 peças de cada espécie, tendo cinco delas permanecido dispostas na solução durante 8 dias e cinco tiveram seus topos invertidos após o sexto dia de tratamento. As peças foram secas ao ar, retiraram-se discos de 2,0 cm de espessura para a determinação da penetração (cinco posições nas peças) e para a retenção do CCB (três posições). Os valores das características das madeiras indicaram que as peças eram homogêneas. A absorção da solução foi de 19,9 litros (algaroba) e de 17,0 litros (leucena), acarretando em uma retenção nominal de CCB de 7,72 e 5,34 kg de ingredientes ativos (i.a.)/m3, respectivamente. De maneira geral, a inversão das peças na solução preservativa é recomendável, por proporcionar uma melhor distribuição, penetração e retenção do CCB ao longo da peça tratada.

Chemical attributes of soil fertilized with cassava mill wastewater and cultivated with sunflower.

The use of waste arising from agroindustrial activities, such as cassava wastewater, has been steadily implemented in order to reduce environmental pollution and nutrient utilization. The aim of this study is that the changes in chemical properties of dystrophic red-yellow latosol (oxisol) were evaluated at different sampling times after reuse of cassava wastewater as an alternative to mineral fertilizer in the cultivation of sunflower, hybrid Helio 250. The experiment was conducted at the Experimental Station of the Agricultural Research Company of Pernambuco (IPA), located in Vitória de Santo Antão. The experimental design was randomized blocks with 6 × 5 subplots; six doses of cassava wastewater (0; 8.5; 17.0; 34.0; 68.0; and 136 m3 ha−1); and five sampling times (21, 42, 63, 84, and 105 days after applying the cassava wastewater), with four replications. Concentrations of available phosphorus and exchangeable potassium, calcium, magnesium and sodium, pH, and electrical conductivity of the soil saturation extract were evaluated. Results indicate that cassava wastewater is an efficient provider of nutrients to the soil and thus to the plants, making it an alternative to mineral fertilizers.

Variabilidade espacial de atributos físicos de um latossolo vermelho-amarelo, sob lavoura cafeeira

O conhecimento da variabilidade dos atributos físicos do solo é importante para o monitoramento da qualidade do solo, pois eles estão diretamente relacionados com a sustentabilidade da produção agrícola. Este estudo teve como objetivos avaliar e identificar as estruturas de dependência espacial, por meio da construção de semivariogramas, num Latossolo Vermelho-Amarelo (LVA), sob lavoura cafeeira; caracterizar as distribuições espaciais dos atributos físicos pela krigagem ordinária; e identificar a camada com maior impedimento físico. O experimento foi conduzido num LVA textura muito argilosa na Fazenda da Empresa de Pesquisa Agropecuária de Minas Gerais, em Patrocínio, MG. A amostragem foi realizada em trincheiras confeccionadas nas intersecções de uma malha retangular de 40 x 150 m, perfazendo um total de 28 pontos, de onde foram coletadas amostras indeformadas em anéis metálicos de 2,54 cm de altura e 6,30 cm de diâmetro, com auxílio do amostrador tipo Uhland. Cada trincheira possuía três degraus de 2,0 x 1,5 m de superfície, nas camadas de 0,00; 0,10; e 0,25 m, onde se coletaram sete amostras indeformadas em cada degrau, dispostas em forma matricial, totalizando 588 amostras. Os atributos físicos do solo apresentaram estrutura de dependência espacial em todas as camadas, exceto a porosidade total. A técnica de krigagem ordinária demonstrou ser alternativa viável para a estimativa de dados em pontos não amostrados na área experimental. A camada de 0,00-0,03 m apresentou maior impedimento físico ao crescimento de raízes, por apresentar maior densidade e menor macroporosidade do solo.

Genetic diversity and molecular characterization of physic nut genotypes from the active germplasm bank of the Agricultural Research Company of Minas Gerais, Brazil

The genetic diversity among 46 accessions of physic nut was estimated with Nei and Li’s similarity coefficient based on a collection of 69 random amplified polymorphic DNA (RAPD) sequences and 37 inter-simple sequence repeat (ISSR) polymorphic loci. The genetic distance between accessions ranged from 0.13 to 0.76, with an average genetic distance of 0.21. The most divergent genotypes were 86, 71 and 83. A dendrogram (generated by the unweighted pair group method with arithmetic mean, UPGMA) of the joint data matrix was constructed and presented only two phylogenetic groups, one of which contained only three individuals; the remaining group included 95.6% of the analyzed genotypes. The low genetic diversity measured in this study indicates the need to broaden the genetic base and increase the variability of this species. The amplification products generated by amplification of SSR primers were used to characterize toxicity alleles, and none of the accessions presented patterns characteristic of non-toxic accessions.

Environmental and genetic effects on the lactation curves of four genetic groups of crossbred Holstein-Zebu cows

The objective of this study was to evaluate the effects of genetic group and environmental factors, including farm of origin, season of calving and lactation number, on the individual lactation curves of 1,010 Holstein-Gyr, Guzerat-Holstein, Holstein-Nellore, and Holstein-Zebu F1 cows on the experimental farms of the Agricultural Research Company in Minas Gerais (Empresa de Pesquisa Agropecuaria de Minas Gerais, EPAMIG). Least squares analysis and the incomplete gamma function were used to investigate differences in early milk yield, peak milk yield, time from onset to the lactation peak, persistency, total milk yield and lactation duration. The highest early yields were observed for Holstein-Gyr and Holstein-Zebu, and the lowest were observed for Holstein-Nellore cows. Early yield increased with lactation number, and the lactations that began in the late rainy and early dry seasons had the highest early yield. The time between lactation onset and the lactation peak was longer for primiparous Holstein-Gyr and Holstein-Guzerat cows. The lowest yields at the lactation peak were observed for the first lactation number. The highest values of persistency were observed for the first lactation number in Holstein-Guzerat cows. Total production from Holstein-Gyr and Holstein-Zebu cows were higher by approximately 14% and 29% compared with Holstein-Guzerat and Holstein-Nellore cows, respectively. The highest total yields were observed in lactations beginning in the dry season. Total yield increased with lactation number. The shortest lactation periods were observed in lactations beginning late in the rainy season. The incomplete gamma function was used to fit the individual curves from the genetic groups evaluated. The total yield differences were linked to early yields and yields at the peak of lactation.

Haemonchus contortus: A multiple-resistant Brazilian isolate and the costs for its characterization and maintenance for research use

The aim of this work was to determine the resistance level of Haemonchus contortus isolated from the Santa Inês flock of the Embrapa (Brazilian government's Agricultural Research Company), Southeast Livestock Unit (CPPSE), as well as to determine costs of characterizing and maintaining this isolate in host donors. Forty-two male Santa Inês lambs were experimentally infected with 4000 H. contortus infective larvae of the field isolate of CPPSE, called Embrapa2010, and divided into six treatment groups, which received triclorfon, albendazol plus cobalt sulfate, ivermectin, moxidectin, closantel and levamisole phosphate, as well as a negative control group (water). Egg per gram (EPG) counts were performed at 0, 3, 7, 10 and 14days post treatment when the animals were slaughtered for parasite count. The data were analyzed using the RESO statistical program, considering anthelmintic resistance under 95% of efficacy. EPG and worm count presented a linear and significant relation with 94% determination coefficient. The susceptibility results obtained by RESO through both criteria (EPG and worm count) were equal, except for closantel, showing that the isolate Embrapa2010 is resistant to benzimidazoles, macrocyclic lactones and imidazothiazoles. The need of a control group did not appear to be essential since the result for susceptibility in the analyses with or without this group was the same. Suppression in egg production after treatment did not occur in the ivermectin and moxidectin groups. In the control group, the establishment percentage was just 12.5 because of the low number of third-stage larvae, resistance (innate and infection immunity) of the animals studied plus good nutrition. Drug classes presented similar efficacy between adults and immature stages. The costs for isolate characterization were calculated for 42 animals during 60days. The total cost based on local market rates was approximately US$ 8000. The precise identification of Brazilian isolates and their establishment in host donors would be useful for laboratorial anthelmintic resistance diagnoses through in vitro tests, which has an annual cost of approximately US$ 2500 for maintenance in host donors.

Oviposition of Quesada gigas (Hemiptera: Cicadidae) in coffee plants

Branches of coffee-plant were collected in São Sebastião do Paraíso County, Minas Gerais State, at the Experimental Station of the Agricultural Research Company (Empresa de Pesquisa Agropecuária de Minas Gerais - EP- AMIG), with the aim of studying various aspects of oviposition by Quesada gigas (Hemiptera: Cicadidae). The number of branches with Q. gigas egg nests was analyzed, as well as the number of nests per branch, the eggs per nest and the diameter of the egg nest location on the branch. The preference for oviposition either on alive or dry branches and the size of the egg were assessed. Egg-laying occurred only on dry branches. The mean of the branch diameter on which the egg nests occurred was 2.5 ± 0.53 mm. The number of eggs per nest averaged 13.2 ± 4.9, and the number of egg nests per branch was 2.2 ± 1.74. The eggs were 1.9 ± 0.08 mm long by 0.5 ± 0.04 mm wide. The largest diameters of the branches containing egg nests were found on the upper third of the trees, as well as the greatest amount of branches with egg nests, of egg nests per branch and of eggs per nest. The correlation relationship between all of the experiment variables was positive.

Alterações nos atributos químicos de um latossolo pelo manejo de plantas invasoras em cafeeiros

O controle de plantas invasoras é uma das práticas de manejo mais intensivas na condução de lavouras cafeeiras, o qual provoca alterações nos atributos químicos do solo. Diante disso, os objetivos deste estudo foram: avaliar os efeitos dos diferentes sistemas de manejo de plantas invasoras em uma lavoura cafeeira nos atributos químicos de um Latossolo Vermelho distroférrico em relação ao solo sob mata nativa (MATA); e verificar a relação entre o teor de C orgânico do solo (COS) e a capacidade de troca de cátions efetiva (CTC a pH natural) e a capacidade de troca de cátions a pH 7 (CTC a pH 7). O estudo foi realizado na fazenda experimental da Empresa de Pesquisa Agropecuária de Minas Gerais (EPAMIG), localizada no município de São Sebastião do Paraíso, Minas Gerais. A área experimental foi plantada com cafeeiros da cultivar Paraíso, e o experimento foi instalado em blocos casualizados, com sete manejos de plantas invasoras e três repetições. Os manejos de plantas invasoras avaliados foram: sem capina (SCAP); capina manual (CAPM); herbicida de pós-emergência (HPOS); roçadora (ROÇA); enxada rotativa (ENRT); grade (GRAD); e herbicida de pré-emergência (HPRE). Cada manejo de plantas invasoras nas entrelinhas dos cafeeiros vem sendo realizado há 30 anos em três ruas, com 36 m de comprimento cada. As amostras de solo foram coletadas no centro das entrelinhas dos cafeeiros em dezembro de 2007, com cinco amostras simples por parcela, que perfizeram uma amostra composta em três profundidades (0-3, 10-13 e 25-28 cm). As seguintes análises químicas foram realizadas nas amostras de solo: pH em água, cátions trocáveis (Ca, Mg, K e Al), C orgânico (COS), capacidade de troca de cátions efetiva ou a pH natural (CTC efetiva) e capacidade de troca de cátions a pH 7. Os manejos apresentaram características contrastantes, variando desde métodos manuais até capinas químicas e mecânicas. Os resultados permitiram observar que a manutenção das plantas invasoras nas entrelinhas dos cafeeiros, adotada no manejo sem capina, contribuiu positivamente para as alterações dos atributos químicos (Ca trocável, CTC efetiva e CTC a pH 7,0) nas três profundidades estudadas; além disso, elevou o teor de C orgânico total na profundidade de 0-3 cm e pode contribuir para aumento e manutenção dos estoques de C em lavouras cafeeiras. Assim, o manejo SCAP nas entrelinhas dos cafeeiros pode ser adotado para a melhoria e manutenção dos atributos químicos em lavouras cafeeiras. Por outro lado, a utilização constante e por longo prazo (30 anos) do manejo HPRE reduziu os valores de pH nas profundidades de 10-13 e 25-28 cm e do Ca trocável, Mg trocável e CTC efetiva nas três profundidades estudadas, em relação aos demais manejos de plantas invasoras. Os valores de CTC efetiva do Latossolo Vermelho distroférrico apresentaram relação com o teor de C orgânico em 59, 60 e 47 % dos casos e de CTC a pH 7 em 65, 55 e 46 %, nas profundidades de 0-3, 10-13 e 25-28 cm.

Different forage sources for F1 Holstein × Gir dairy cows

We evaluated the effect of four different forage sources on the performance of crossbred dairy cows under tropical conditions. The experiment was carried out on the Experimental Farm of the Agricultural Research Company of Minas Gerais, in Felixlândia-MG, Brazil. Twelve crossbred F1 Holstein×Gir cows were allocated to a triplicated 4×4 Latin square, balanced for residual effect, with each diet assigned to one group of three cows each period. The experiment had four treatments and five experimental periods of 21days, with 14days for adaptation and 7days for data collection. The treatments included sorghum silage, corn silage, fresh sugarcane and sugarcane silage treated with 1% calcium oxide. Three markers LIPE®, titanium dioxide and iADF were used to estimate the individual intake and the apparent digestibility of the feed for the cows in each group. The data were subjected to analysis of variance and compared by a Tukey's test at 5% probability using the PROC GLM of SAS, version 8.0 for Windows software. The dry matter intake (DMI) and organic matter intake (OMI) were highest (P<0.05) for cows consuming corn silage (P<0.05) than for cows consuming sorghum silage, fresh sugarcane and sugarcane silage. The DMI for fresh sugarcane was lower than for corn silage and sorghum silage (P<0.05). DMI was least when cows were fed sugarcane silage (P<0.05). The dry matter digestibility (DMd) and organic matter digestibility (OMd) of corn silage, sorghum silage and fresh sugarcane were similar (P>0.05) but all were higher than for the sugarcane silage-based diet (P<0.05). Milk yield by cows fed corn silage and sorghum silage was similar (P>0.05) but both were higher than for cows fed sugarcane silage and fresh sugarcane. Non-esterified fatty acids in the plasma were the greatest (P<0.05) for cows fed sugarcane silage. Nitrogen balance was the greatest for cows fed corn and sorghum silage, followed by fresh sugarcane and then sugarcane silage (P<0.05). The sugarcane silage-based diet resulted in low intake, low digestibility, low efficiency of nitrogen utilization, and high mobilization of body reserves by F1 Holstein×Gir cows, but supported a milk production similar to cows fed fresh sugarcane. Corn silage and sorghum silage resulted in satisfactory cow performance and nitrogen utilization, even when the forage:concentrate ratio was high.