ABSTRACT This study aimed to determine the effects of relocation time (RT; Experiment 1) and storage time after relocation (ST; Experiment 2) on microbial population, fermentative characteristics, and chemical composition of corn silage. In experiment 1, corn silage was stored for 30 d, subjected to different RT (0–60 h), and stored again for 30 d. Thirty experimental silos were used in a completely randomized design, with three replicates per treatment. In experiment 2, after 150 d of ensiling, silage was removed from a bunker silo, exposed to air for 9 h, relocated to experimental silos, and stored for periods ranging from 0 to 128 d. Twenty-eight experimental silos were used in a completely randomized design, with four replicates per treatment. Relocation time had no effect on fungi counts and concentrations of lactic and propionic acids in corn silage but resulted in a significant increase in dry matter content. In experiment 2, dry matter recovery and concentration of non-fiber carbohydrates decreased in corn silage stored for more than 32 d after relocation. Exposure of corn silage to air during relocation for up to 60 h followed by 30 d of storage did not compromise the fermentation profile or nutritive value of the silage. Increased storage time of relocated corn silage (up to 128 d) consistently decreases its nutritional value. The storage period seems to have an increased impact on nutrient loss in relocated silage than the relocation period.

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.

Resumo O texto apresenta resultados de um estudo que visa a compreender as relações que estudantes do 9º ano do Ensino Fundamental estabelecem com o rio Doce no contexto do rompimento da barragem de Fundão. O aporte teórico e metodológico são as contribuições de Bernard Charlot em diálogo com o campo da educação ambiental. Os dados foram gerados por meio de balanço de saber e de entrevistas. Os resultados indicam preponderância de aprendizagens afetivas sobre as aprendizagens escolares e cidadãs. Por sua vez, é para a escola que os estudantes direcionam suas demandas de aprendizagens, atribuindo-lhes sentidos no contexto do desastre sociotécnico. Afirma-se a importância da escola para a tomada de decisões coletivas e para a atuação no contexto do desastre de forma socialmente responsável.

Abstract This paper presents the results of a study that aims to understand the relations that 9th-grade students establish with the Rio Doce in the context of the Fundão dam rupture. The theoretical and methodological basis is the contributions of Bernard Charlot through a dialogue with the field of environmental education. The data was generated through the inventory of knowledge and interviews. The results indicate the preponderance of affective learning over the school and citizen learning. In turn, it is towards the school that students direct their learning demands, giving them meanings in the context of the socio-technical disaster. The importance of the school for collective decision-making and socially responsible action in the context of the disaster is therefore affirmed.

Resumen El texto presenta los resultados de un estudio que tiene como objetivo comprender las relaciones que los estudiantes de noveno año de enseñanza básica establecen con el río Doce en el contexto de la ruptura de la presa de Fundão. Las aportaciones teórica y metodológica vienen dadas por las ideas de Bernard Charlot en diálogo con el área de la educación ambiental. Los datos se generaron a través de un equilibrio entre inventários de saber y entrevistas. Los resultados indican una preponderancia del aprendizaje afectivo sobre el aprendizaje escolar y ciudadano. A su vez, es a la escuela donde los estudiantes dirigen sus demandas de aprendizaje, asignándoles sentidos en el contexto del desastre socio-técnico. Se afirma la importancia de la escuela para la toma de decisiones colectivas y para actuar en el contexto del desastre de una manera socialmente responsable.

RÉSUMÉ Ce texte présente les résultats d’une étude visant à comprendre les rapports que des élèves de troisième entretiennent avec le Rio Doce après la rupture du barrage minier du Fundão. Le cadre théorique et méthodologique est basé sur la contribution de Bernard Charlot en dialogue avec le domaine de l’éducation environnementale. Les données ont été obtenues par moyen d’un bilan de la litterature et d’entretiens. Les résultats indiquent que les apprentissages d’ordre affectif prédominent sur les apprentissages scolaires et citoyens. Ce sont les élèves eux-mêmes qui demandent à l’école des enseignements qu’ils considerent significatifs dans le contexte du désastre socio-technique. L’importance de l’école dans la prise de décisions collectives et pour l’action socialement responsable dans le contexte du désastre est soulignée.

ABSTRACT The objective of this research was to characterize the nutritive value of corn silage made on intensive dairy farms and demonstrate the nutritional variations between silages located at the top and at the center of a bunker silo. Thirty-two dairy farms were visited in four Brazilian states. One corn bunker silo of each farm was chosen and samples were collected from the top and center parts. The nutritive value, fermentation end-products, and microbial counts were assessed. The predicted milk was determined by Milk2006 spreadsheet. The mean, standard deviation, maximum, minimum, and 95% confidence interval of all data were calculated. The ash, neutral detergent fiber (NDF), starch, in vitro NDF, and dry matter (DM) digestibility data were compared with reference value. Both statistical procedures were performed through the PROC MEANS of SAS. The mean values found at the center for NDF, starch, total digestible nutrients (TDN-1x), and estimated milk were 503 g kg−1 DM, 308 g kg−1 DM, 583 g kg−1, and 1,124 kg t−1, respectively. The top silages presented a mean TDN-1x and predicted milk of 559 g kg−1 and 1046 kg t−1, respectively. For NDF digestibility and starch concentration, 53.1% and 62.5% of the center samples presented a value equal to or above the reference value (500 g kg−1 and 300 g kg−1 DM for NDF digestibility and starch concentration, respectively). Overall, the corn silage produced on intensive dairy farms in Brazil has satisfactory nutritive value, especially in terms of starch concentration. Some parameters, such as the concentration of fiber and its digestibility, should be improved. This study also shows that a silo may contain two different types of silage: top and center. This alerts nutritionists and farmers when feeding and sampling corn silage from bunker silos.

Gradual reduction of legumes in mixed tropical pastures requires periodic oversowing. Exploiting the carrying capacity of grass for an extra year after the disappearance of legumes can be economically advantageous to the farmer. This study aimed to evaluate the productivity of Xaraés palisadegrass (Brachiaria brizantha) pastures in response to its historical association with stylo (Stylosanthes guianensis) under two canopy heights to determine whether different grazing management conditions affect the defoliation pattern left by grazing animals. The split-plot experimental design was used, with the historical botanical composition (HBC) (24, 34, 45 and 52 % legume composition) corresponding to the main plots and the canopy frequency of defoliation determined at heights of 30 and 45 cm for Xaraés palisadegrass corresponding to the subplots with two replicates (500 m2) grazed by Tabapuã cows. Pastures with over 34 % stylo in the botanical composition remained productive for one year after legume disappearance, accumulating more than 8 mg ha−1 of forage per year. Xaraés palisadegrass pastures at a height of 30 cm provided better canopy structure, with 64 % less stem production and 43 % less dead material. The 30-cm pre-grazing canopy height provided a grazing environment conducive to forage intake by animals that resulted in efficient use of the pasture. In response to the improved canopy structure, the cows grazed an average of 60 fewer minutes. A HBC greater than 34 % of legumes in the pastures allows for the postponement of legume oversowing until the next growing season.

Objetivou-se com este estudo avaliar o efeito da adição de farelo de dendê (BP) como aditivo na silagem de capim-elefante. A composição química e fermentação foram analisadas em delineamento experimental inteiramente casualizado, com seis tratamentos, sendo um sem BP (C) e seis repetições, em que as médias dos resultados dos dias de fechamento e abertura foram analisadas por análise de regressão. As amostras foram coletadas no momento da ensilagem e após 190 dias de armazenamento para avaliação da matéria seca, proteína bruta, carboidratos (total, não fibrosos, solúvel em água, celulose e hemicelulose), cinzas, lignina e extrato etéreo. Na fase aeróbia, foram coletadas amostras para pH, nitrogênio amoniacal, fungos e leveduras. O capim-elefante do experimento apresentou valores de 13,9% de MS e 8,25% de PB, enquanto a BP tem 77,2% de MS e 16,9% de PB. A inclusão de BP inibiu o crescimento de fungos e leveduras. O aumento do teor de BP diminuiu a concentração de NH3-N. Maiores concentrações de BP tornaram as silagens mais estáveis, tendo sua quebra em 72 horas, enquanto que a estabilidade de C foi de 19 horas. As silagens com concentrações superiores a 15% BP não apresentaram variações significativas no pH, na fase aeróbica. A inclusão de farelo de palma, em concentrações de 10% a 15% pode ser usado em silagem de elefante, inibindo fermentação indesejável e tornando-as mais estáveis. Concentrações acima deste valor podem afetar o valor nutritivo da silagem pelo alto teor de lignina do aditivo.

The objective of this study was to evaluate the effect of adding palm kernel meal (BP) as an additive in elephant grass silage. The chemical qualitative and fermentation were analysed in a completely randomized design with six treatments, one with no BP (C) and six replications, where the averages of the results of days of closing and opening were analysed by regression analysis. We collected samples at the time of ensiling and after 190 days of storage for evaluation of dry matter, crude protein, carbohydrates (total, non-fibrous, water-soluble, cellulose and hemicellulose), ash, lignin and ether extract. In aerobic phase, we collected samples for pH, ammoniacal nitrogen, fungi and yeasts. The elephant grass of this experiment showed values of 13.9% DM and 8.25% CP while the BP has 77.2% DM and 16.9% CP. The inclusion of BP had inhibited the growth of fungi and yeasts. The increase in the content of BP decreased the concentration of NH3-N. Higher concentrations of BP in silage were more stable, and the stability breaks in 72 hours, while the stability of C was 19 hours. Concentrations above 15% BP had no significant variations in pH in the aerobic phase. The inclusion of palm kernel meal at concentrations 10% to 15% can be used in silage of elephant grass, inhibiting undesired fermentation and making them more stable. Concentrations above this value may affect the nutritive value of silage by high lignin content of the additive.

The objective of this study was to evaluate the effect of covering methods on the nutritive value of corn silage and performance of dairy cows. Whole-plant corn was harvested at 340 g/kg of dry matter (DM) and ensiled for 135 d in horizontal silos covered with one of the following methods: oxygen barrier film (45-µm thick) + white-on-black polyethylene film (200-µm thick) over the oxygen barrier film (OB+WB); white-on-black polyethylene film (200-µm thick) (WB); black polyethylene film (200-µm thick) (B); or recycled black polyethylene film (200-µm thick) covered with a layer of 10 cm of sugarcane bagasse (RB+SB). Nutrient composition, fermentation profile, and yeast and mold counts in edible silages were similar across treatments. Silage temperature during the storage period was 24.6, 28.7, 28.4 and 33.1 °C for RB+SB, OB+WB, WB and B, respectively, and the proportion of spoiled silage ranged from 28.7 (for the RB+SB treatment) to 74.2 g/kg DM (for the B treatment). Dry matter intake was similar across treatments and averaged 21.9 kg/d. Milk production was higher for cows fed corn silage covered with RB+SB (34.4 kg/d) compared with those fed corn silage covered with B (30.4 kg/d), resulting in higher feed efficiency for RB+SB treatment. Silages covered with OB+WB and WB had intermediate values. In vivo digestibility of organic matter was higher for cows fed corn silage covered with RB+SB compared with those fed corn silage covered with WB and B, but were similar to those fed corn silage covered with OB+WB. The utilization of oxygen barrier films and the protection of polyethylene film with sugarcane bagasse are effective strategies to increase the recovery of digestible nutrients and, consequently, to enhance production efficiency of lactating dairy cows.

A reconstituição da fertilidade do solo é um dos caminhos para se recuperar a capacidade produtiva da pastagem em degradação. A adubação nitrogenada é fundamental para o aumento da produção de forragem, principalmente, quando se trata da recuperação de pastagens. Diante disso, o objetivo do trabalho foi avaliar as características estruturais e o acúmulo de massa seca (MS) de lâminas foliares e colmos mais bainhas do capim-marandu de pastagem em estágio moderado de degradação, sob doses e fontes de nitrogênio (N), por três anos. O experimento foi conduzido de julho de 2003 a março de 2006, na Fazenda Modelo da Universidade Estadual de Goiás (UEG), em uma área de 882 m², com parcelas de 20 m² e área útil de 6 m². O delineamento experimental utilizado foi o de blocos ao acaso, com três repetições. Os tratamentos nas parcelas foram caracterizados pelo fatorial 2 x 4, sendo duas fontes de N (sulfato de amônio e uréia) e quatro doses de N (0; 100; 200 e 300 kg ha-1 ano-1). Na subparcela, os tratamentos foram representados pelos anos (2004; 2005 e 2006), referentes ao tempo de recuperação da pastagem. A adubação nitrogenada foi parcelada em três aplicações, após cada corte de avaliação da forrageira. Os resultados obtidos mostraram que a adubação nitrogenada influenciou as características estruturais e o acúmulo de massa seca do capim-marandu, e, consequentemente, a sua recuperação. A dose de 300 kg ha-1 ano-1 de sulfato de amônio proporcionou maiores valores de altura de plantas, densidade de perfilhos e massa seca das lâminas foliares.

To replenish soil fertility is one of the ways of recovering the productive capacity of degraded pasture. Nitrogen fertilisation is fundamental to increasing forage production, especially when it comes to the recovery of pasture. With this in mind, the objective of this work was to evaluate the structural characteristics and dry matter (DM) accumulation of the leaf blades and sheathed stems of marandu-grass pasture at a moderate stage of degradation, for different dosages and sources of nitrogen, during a three-year period. The experiment was carried out from July, 2003 to March, 2006 at the Model Farm of the Goiás State University (UEG), over an area of 882 m² with plots of 20 m² and usable area of 6 m². The experimental design was of randomized blocks with three replications. The treatments in the plots were characterized by a 2 x 4 factorial, being two nitrogen sources (ammonium sulphate and urea) and four nitrogen dosages (0; 100; 200 and 300 kg ha-1 yr-1). For each sub-plot, treatments were represented by the years (2004, 2005 and 2006), as relating to the time of the recovery of the pasture. Nitrogen fertilization was divided into three applications, following each harvesting of the grass for forage evaluation. The results showed that nitrogen fertilisation influenced the structural characteristics and dry matter accumulation of marandu grass, and hence its recovery. The dosage of 300 kg ha-1 yr-1 of ammonium sulphate resulted in greater values for plant height, tiller density and leaf-blade dry matter.

Fermentation and aerobic stability were evaluated in high-moisture corn (HMC) silage inoculated with different levels of Lactobacillus buchneri. The HMC composed of 654 g/kg dry matter (DM) was ensiled in quadruplicate laboratory silos (7 L) per treatment. L. buchneri 40788 was applied at 5 × 10(4); 1 × 10(5); 5 × 10(5); and 1 × 10(6) cfu/g to the ground corn. Silages with no additive were used as controls. After 140 d of ensiling, the silages were subjected to an aerobic stability evaluation for 12 days in which the chemical parameters, microbiological parameters and silage temperature were measured to determine the aerobic deterioration. The lactic acid, acetic acid and propionic acid concentrations did not differ between silages. The fermentation parameters of HMC were not affected by L. buchneri. The HMC containing L. buchneri had a low number of yeast and mould colonies and a more stable pH until in the eighth measurement, which improved the aerobic stability without affecting gas loss. Doses of L. buchneri greater than or equal to 5 × 10(5) cfu/g applied to the HMC were the most efficient in control of aerobic deterioration.

Inovação tecnológica é o processo que representa o desenvolvimento de novas tecnologias e o aperfeiçoamento das já existentes. A pesquisa referente à silagem envolve vários aspectos agronômicos, bioquímicos, microbiológicos, nutricionais e a engenharia do processo. Colhedoras de forragem, inoculantes e filmes plásticos para a vedação do silo são importantes e recentes desenvolvimentos. A silagem de milho é a principal fonte de energia em rações, mas, atualmente, o uso de outras forrageiras, tais como cana-de-açúcar e leguminosas tem sido incrementado. Duas técnicas de ensilagem são consideradas inovadoras: estocagem em silos tubulares horizontais e silos/fardos revestidos por filme plásticos. Quanto à vedação de silos trincheira ou superfície, o filme de polietileno tem sido o método mais comumente utilizado para proteger a silagem próxima da superficie, porém novos filmes já estão disponíveis ou em processo de desenvolvimento. O filme coextruzado de polietileno/poliamida e o novo filme de polivinil álcool são, recorrentemente, utilizados para cobrir a silagem. Diversos tipos de aditivos são desenvolvidos, na atualidade, com o intuito de melhorar o processo de ensilagem. Lactobacilus buchneri, uma bactéria heterolática obrigatória, pode melhorar a estabilidade aeróbia de silagens e, nos tempos vigentes, é mais efetiva na preservação da silagem de milho do que em outras. A produção de energia a partir de silagem tem despertado o interesse nos últimos anos. Como fruto desse crescente interesse gramíneas perenes tem sido estocadas como biomassa para produzir biocombustíveis nos Estados Unidos, e silagem tem sido utilizada como matéria prima para produção de biogás na Europa.

Technology innovation is the process through which new technologies are developed. Silage research addresses the various agronomical, biochemical, microbiological, nutritional and engineering aspects of the process. Forage harvesters, additives (inoculants), and plastic films for sealing are important recent developments. The corn silage is the major source of energy in rations, but recently the use of other ensiled crops, such as sugarcane and legumes, has been increased. Two newer ensiling techniques are the pressed bag and the wrapped bale. Polyethylene film has been the most common method used to protect silage near the surface, but new plastic films are available or in the process of development. A co-extruded polyethylene-polyamide film and new polyvinyl alcohol film also have been used to seal corn silage. Various types of additives have been developed in order to improve the ensiling process. Lactobacillus buchneri, that is an obligate heterolactic acid bacterium, might improve the aerobic stability of silages and have been more effective in corn silage than in other silages. Energy production from silage has also attracted much interest in recent years, as perennial grasses that have been stored as biomass to produce biofuels in the United States, and silage as feedstock for biogas in Europe.

The characteristics of fermentation and aerobic stability were evaluated in corn silage inoculated with different doses of Lactobacillus buchneri. The whole corn plant (300 g/kg DM) was ensiled in quadruplicate laboratory silos (7L). L. buchneri 40788 was applied at 5×10(4), 1×10(5), 5×10(5) and 1×10(6) cfu/g of fresh forage. Silages with no additive were used as controls. After 130 d of ensiling, the silages were subjected to an aerobic stability evaluation for 12 days, in which chemical and microbiological parameters as well as the temperature of the silage were measured to determine the aerobic deterioration. The addition of L. buchneri resulted in increased acetic acid concentrations. The number of yeast colonies was low in all treated silages. The pH, lactic and propionic acid concentrations did not differ between silages. Under aerobic conditions, all the treated silages showed a low number of yeasts and a great aerobic stability. Therefore, L. buchneri is effective against yeasts and improves the aerobic stability of corn silage in laboratory silos. However, doses equal or superior to 1×10(5) cfu/g of fresh forage were more efficient in the control of aerobic spoilage.

Objetivou-se avaliar o efeito da queima e do uso de aditivos (ureia, benzoato de sódio, hidróxido de sódio (NaOH), Propionibacterium acidipropionici + Lactobacillus plantarum e Lactobacillus buchneri) na ensilagem de cana-de-açúcar. Utilizou-se o delineamento inteiramente casualizado, em esquema fatorial 2 (cana-de-açúcar crua e queimada) × 6 (cinco aditivos mais o grupo controle) com três repetições. Determinaram-se as perdas durante o processo fermentativo nas formas de gases e de efluentes e a recuperação de matéria seca (MS). Maior recuperação de MS foi observada nas silagens de cana-de-açúcar queimada (77,3%) em relação às silagens de cana crua (73,1%). As recuperações de MS observadas nas silagens tratadas com NaOH ou L. buchneri foram de 84%, enquanto das silagens controle, 69%. No período após abertura, uma variável importante é a inibição da elevação do pH, nesse caso, medida pela variação do pH. Destacam-se como inibidores da variação do pH o benzoato de sódio e o L. buchneri, que promoveram variação do pH de 0,05 e 0,18 unidade de pH, respectivamente. A ensilagem da cana-de-açúcar sem aditivos, crua ou queimada, é uma estratégia que resulta em grandes perdas quantitativas, que podem ser evitadas pelo uso de aditivos. Entre os aditivos avaliados, o L. buchneri é o que atua de forma mais satisfatória nas fases de fermentação e pós-abertura de silagens de cana-de-açúcar crua ou queimada.

This research was conducted to evaluate the effects of burning and additivess (urea, sodium benzoate, sodium hydroxide (NaOH), Propionibacterium acidipropionici + Lactobacillus plantarum and Lactobacillus buchneri) on sugar cane silage. A randomized complete design was used, in a 2 × 6 factorial scheme with two sugar cane forages (natural or burned) and six treatments (five additive sources plus a control) with three replications. The gas and effluent losses during the fermentation process and dry matter recovery (DMR) were determined. Greater DMR was observed in the burned sugar cane silage (77.3%) compared to the crude silage (73.1%). Among the additives, greater DM recovery was observed in the silages treated with the NaOH or L. buchneri silage, that showed 84.0% DMR, and the control silage with 69.0%. After opening, an important aspect is the inhibition of pH elevation, in this case, measured by the variation in the pH values (VpH). Sodium benzoate and L. buchneri were efficient inhibitors of the VpH, showing values of 0.05 and 0.18 per pH unit, respectively. Ensiled sugar cane without additives, raw or burned, is a strategy that presents high quantitative losses. L. buchneri effectively reduces losses during the fermentation and post-opening phases of raw or burned sugar cane silage.

Esta pesquisa foi realizada com os objetivos de caracterizar a microbiologia e avaliar a estabilidade aeróbia de silagens de capim-marandu contendo polpa cítrica peletizada (PCP). A forragem colhida foi submetida aos seguintes tratamentos: silagem de capim-marandu; silagem de capim-marandu + 5% PCP e silagem do capim-marandu + 10% de PCP com base na matéria natural. As alterações químicas e microbiológicas foram feitas aos 0, 2, 4 e 6 dias após a abertura dos silos (tambores de metal com 80 cm de altura e 50 cm de diâmetro). Na avaliação da estabilidade aeróbia por meio da alteração da temperatura, 3 kg de silagem foram colocados em caixas de isopor, que foram armazenadas em câmara climática. Nos dois ensaios realizados, utilizou-se delineamento inteiramente ao acaso com cinco repetições, em esquema de parcelas subdivididas, de modo que os níveis de PCP na silagem corresponderam às parcelas e o tempo, às subparcelas. As silagens sem polpa apresentaram desenvolvimento de bacilos e enterobactérias e aumento do pH no decorrer do desabastecimento dos silos. A presença de leveduras foi detectada nas silagens contendo o aditivo e aumentou do primeiro ao sexto dia de aeração. A digestibilidade in vitro da matéria seca (DIVMS) reduziu com o aumento dos tempos de aeração. A temperatura nas silagens com 10% de PCP aumentou durante a aerobiose. Com a abertura dos silos, as silagens apresentaram-se instáveis, seja pelo desenvolvimento de bactérias seja pelo desenvolvimento de leveduras, o que reduziu seu valor nutritivo.

This trial had the objective of characterizing the microbial population and evaluating the aerobic stability of Marandu grass silages with pelleted citrus pulp (PCP). The collected forage was submitted to the following treatments: Silage of Marandu grass; silage of Marandu grass + 50 g/kg PCP and silage of Marandu grass + 100 g/kg PCP on natural matter basis. Metal cylindrical containers with 80 cm of height and 50 cm of diameter were used as silos during assays of microbiological dynamics and chemical changes of silages in anaerobiosis. Evaluations were performed on days 0, 2, 4 and 6 after silos were opened. The aerobic stability was evaluated by change in temperature, using approximately three kilograms of silage inside styrofoam boxes that were placed inside a climatic chamber. A completely randomized experimental design and split plot arrangement were used in the two assays, with five replications. Treatments were the plots and time was the subplots. Bacillus and enterobacteria were present on the Marandu grass silages with 0 g/kg PCP, which also showed pH increase throughout the feedout phase. Yeast was detected on the silages that were added with PCP. A trend of increasing temperature with extension of the aeration time was observed mainly in the silages containing 100 g/kg PCP. Isolated yeast strains showed lactate assimilation. Silages were found to be unstable due to the silo opening, both by bacterial or yeast development, which reduced the nutritional value.

As silagens de milho e de sorgo são importantes fontes de energia em rações utilizadas na bovinocultura leiteira, sendo que a estocagem desses volumosos é realizada em silos horizontais com ou sem a presença de paredes laterais (trincheira ou superfície, respectivamente), os quais são atrativos em razão do baixo custo de armazenamento, porém suas conformações determinam grande superfície de exposição, o que torna as silagens mais susceptíveis a deterioração aeróbia. Os maiores problemas envolvendo a qualidade microbiológica e nutricional em silagens, estão relacionados às práticas de manejo na colheita, no abastecimento e compactação da massa, na vedação e, principalmente, durante o desabastecimento do silo. O controle da deterioração aeróbia em silagens pode ser o principal ponto para melhorar a qualidade química, sensorial e higiênica em queijos e no leite fresco. A deterioração aeróbia causa perdas nutricionais e de matéria seca (MS), podendo provocar efeitos indiretos ao animal e ao homens pela transferência de microrganismos patogênicos e micotoxinas ao longo da cadeia alimentar. O presente trabalho tem por objetivo discutir práticas de manejo em fazendas que utilizam silos horizontais no armazenamento de silagem de milho e de sorgo e que produzem leite destinado à fabricação de queijos (tipo pasta dura) que possuem Denominação de Origem Protegida, além de definir aspectos ligados ao manejo na produção de silagens e no controle da deterioração aeróbia das mesmas.

Maize and sorghum silages are good sources of energy for lactating dairy cows that produce milk destined for fresh and matured cheeses. Silages are usually stored in horizontal silos with or without side walls on commercial farms throughout the world. The main microbiological and nutritional quality problems are related to harvesting time, ensiling technology, and management practices during filling and feed-out. Aerobic deterioration is a key point that must avoided on farms in order to improve the hygienic, chemical and sensorial quality of milk and cheeses. Aerobic deterioration causes large losses of dry matter (DM) and quality, and it can cause health problems for animals and humans through the transfer of pathogens and mycotoxins from feed and livestock to food products. The objectives of the present work were to overview management practices connected to the storage of maize and sorghum in horizontal silos on farms producing milk for make Protected Designation of Origin (PDO) hard ripened cheese, to define good management practices that should be applied as the basis for safe silage production and to reduce the extent of aerobic deterioration.

Objetivou-se avaliar silagens de cana-de-açúcar tratadas com aditivos químicos (uréia 1,5%; benzoato de sódio 0,1%; ou hidróxido de sódio (NaOH) 1% na matéria natural) combinados ou não com inoculantes (Propionibacterium acidipropionici + Lactobacillus plantarum ou Lactobacillus buchneri). Foram avaliadas 12 silagens: uma controle, sem inoculante e sem aditivo químico; três sem inoculante, mas com um dos aditivos; uma com P. acidipropionici + L. plantarum, sem aditivo químico; três com P. acidipropionici + L. plantarum e um dos aditivos; uma com L. buchneri, sem aditivo químico; e três com L. buchneri e um dos aditivos. Os dados foram analisados em esquema fatorial 4 × 3 com três repetições para cada tratamento. Foram determinadas as perdas ocorridas durante o processo fermentativo nas formas de gases e de efluentes e a recuperação da MS. Durante a exposição aeróbia, determinaram-se a recuperação da MS e a estabilidade aeróbia medida pela variação da temperatura. A associação de L. buchneri e NaOH reduziu as perdas por gases e efluentes e elevou a recuperação da MS. No período após abertura, destacou-se a atuação do benzoato de sódio em manter o pH com variação de apenas 0,1 unidade em cinco dias de exposição aeróbia e dos inoculantes L. buchneri e P. acidipropionici + L. plantarum em prolongar o tempo para elevação da temperatura de 34 horas nas silagens controle para 54 e 50 horas, respectivamente. A ensilagem de cana-de-açúcar requer a inclusão de algum aditivo eficiente no controle das perdas quantitativas durante a fermentação e a exposição aeróbia.

The experiment was carried out to evaluate sugar cane silage treated with chemical additive: urea 1.5%, sodium benzoate 0.1%, and sodium hydroxide 1.0% on the wet basis, associated with Propionibacterium acidipropionici + Lactobacillus plantarum and Lactobacillus buchneri, plus control silage in a factorial scheme 4 x 3, with three replications. The gas and effluents losses during the fermentation phase, and dry matter recovery were determined. During the aerobic phase were determined the dry matter recovery and aerobic stability through the temperature variation. The Lactobacillus buchneri and NaOH association reduced gas and effluent losses and increased the dry matter recovery. At the aerobic phase, the sodium benzoate maintained the pH values, with changes of 0.1 unit during five days. The time to temperature elevation increased from 34 hours on the control silage to 54.0 and 50.0 hours, respectively on the silage inoculated with Propionibacterium acidipropionici + Lactobacillus plantarum or Lactobacillus buchneri. The sugar cane silage production required an efficient additive inclusion which can control the quantitative losses during the fermentation and aerobic phases.