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ABSTRACT: The objective was to evaluate the effect of nitrogen fertilization levels on productivity, and nutritional value of BRS Kurumi managed at different residue heights during rainy and dry periods of the year. The pasture was managed in three residue heights (20, 35, and 50 cm) and three nitrogen fertilization levels (0, 100, and 200 kg N/ha/year) during the rainy and dry seasons. When the height of the grass of each plot reached 80 cm, the Kurumi was cut manually at the pre-established residue heights. Around 89% of the dry matter (DM) production was observed during the rainy season. The residue height of 35 cm together with doses of 100 or 200 kg N/ha/year, and the residue height of 20 cm, with a dose of 100 kg N/ha/year were the treatments that had the highest DM production during the rainy period. No differences in DM production were observed between tested treatments during the dry period. The Kurumi cultivated during the dry period had the highest content of neutral detergent fiber and lowest digestibility. The Kurumi managed with residue heights of 20 and 35 cm and fertilized with 100 kg N/ha had the highest values of efficiency of utilization applied nitrogen. The use of 20 or 35 cm of residue height and 100 kg of N/ha/year is recommended to obtain greater biomass production and nutrients, nutritional quality, and nitrogen use efficiency.

RESUMO: O objetivo foi avaliar o efeito dos níveis de fertilização nitrogenada na produtividade e no valor nutritivo do BRS Kurumi quando manejado em diferentes alturas de resíduos durante os períodos seco e chuvoso do ano. O capim foi manejado em três alturas de resíduos (20, 35 e 50 cm) em associação com três níveis de fertilização com nitrogênio (0, 100 e 200 kg N/ha/ ano), durante o período seco e chuvoso do ano. Quando a altura do capim de cada parcela atingiu 80 cm, o Kurumi foi cortado nas alturas de resíduos pré-estabelecidas. Cerca de 89% da produção de MS foi observada durante o período chuvoso. A altura do resíduo de 35 cm juntamente com doses de 100 ou 200 kg N/ha/ ano, e a altura do resíduo de 20 cm, com dose de 100 kg N/ha/ ano foram os tratamentos que apresentaram maior produção de MS durante o período chuvoso. Não foram observadas diferenças na produção de MS entre os tratamentos testados durante o período da seca. O Kurumi cultivado no período da seca apresentou maior teor de fibra em detergente neutro e menor digestibilidade. O Kurumi manejado com alturas de resíduo de 20 e 35 cm e fertilizado com 100 kg N/ha apresentou os maiores valores de eficiência de utilização do nitrogênio aplicado. Recomenda-se a utilização de 20 ou 35 cm de altura do resíduo e 100 kg de N/ha/ ano para obter maior produção de biomassa e nutrientes, qualidade nutricional e eficiência no uso do nitrogênio.

RESUMO

The objective was to evaluate the effect of nitrogen fertilization levels on productivity, and nutritional value of BRS Kurumi managed at different residue heights during rainy and dry periods of the year. The pasture was managed in three residue heights (20, 35, and 50 cm) and three nitrogen fertilization levels (0, 100, and 200 kg N/ha/year) during the rainy and dry seasons. When the height of the grass of each plot reached 80 cm, the Kurumi was cut manually at the pre-established residue heights. Around 89% of the dry matter (DM) production was observed during the rainy season. The residue height of 35 cm together with doses of 100 or 200 kg N/ha/year, and the residue height of 20 cm, with a dose of 100 kg N/ha/year were the treatments that had the highest DM production during the rainy period. No differences in DM production were observed between tested treatments during the dry period. The Kurumi cultivated during the dry period had the highest content of neutral detergent fiber and lowest digestibility. The Kurumi managed with residue heights of 20 and 35 cm and fertilized with 100 kg N/ha had the highest values of efficiency of utilization applied nitrogen. The use of 20 or 35 cm of residue height and 100 kg of N/ha/year is recommended to obtain greater biomass production and nutrients, nutritional quality, and nitrogen use efficiency.

O objetivo foi avaliar o efeito dos níveis de fertilização nitrogenada na produtividade e no valor nutritivo do BRS Kurumi quando manejado em diferentes alturas de resíduos durante os períodos seco e chuvoso do ano. O capim foi manejado em três alturas de resíduos (20, 35 e 50 cm) em associação com três níveis de fertilização com nitrogênio (0, 100 e 200 kg N/ha/ ano), durante o período seco e chuvoso do ano. Quando a altura do capim de cada parcela atingiu 80 cm, o Kurumi foi cortado nas alturas de resíduos pré-estabelecidas. Cerca de 89% da produção de MS foi observada durante o período chuvoso. A altura do resíduo de 35 cm juntamente com doses de 100 ou 200 kg N/ ha/ ano, e a altura do resíduo de 20 cm, com dose de 100 kg N/ha/ ano foram os tratamentos que apresentaram maior produção de MS durante o período chuvoso. Não foram observadas diferenças na produção de MS entre os tratamentos testados durante o período da seca. O Kurumi cultivado no período da seca apresentou maior teor de fibra em detergente neutro e menor digestibilidade. O Kurumi manejado com alturas de resíduo de 20 e 35 cm e fertilizado com 100 kg N/ha apresentou os maiores valores de eficiência de utilização do nitrogênio aplicado. Recomenda-se a utilização de 20 ou 35 cm de altura do resíduo e 100 kg de N/ha/ ano para obter maior produção de biomassa e nutrientes, qualidade nutricional e eficiência no uso do nitrogênio.

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Background: Novel feeding strategies should be developed to produce high-quality meat in current goat production systems. Objective: To evaluate the effects of castration and the association of spineless cactus with sugarcane bagasse or elephant grass hay on nutrient intake, digestibility, performance, feeding behavior and carcass traits of feedlot kids. Methods: A total of 24 male kids (12 castrated and 12 intact), with an average initial weight of 18.5 ± 3.8 kg were allotted to a completely randomized 2 x 2 factorial design (sugar cane bagasse or elephant grass hay; intact or castrated), and confined for 70 days. Results: Nutrient intake and animal performance were similar between treatments. Sugarcane bagasse increased, when compared to elephant grass hay, the digestibility of dry matter (66.12 vs 62.88; p=0.005), crude protein (74.26 vs 70.95; p=0.029) and non-fibrous carbohydrates (91.94 vs 83.07; p<0.001). The forage source affected the time spent resting, ruminating and total chewing time, but there was no effect of diet on feeding and rumination efficiencies. Elephant grass hay increased, when compared to sugarcane bagasse, hot carcass weight (9.87 vs 10.79; p=0.025) and hot carcass yield (43.81 vs 46.87; p=0.013). Intact kids produced heavier hot carcasses when compared with castrated kids (10.80 vs 9.86; p=0.014). Conclusion: Feeding intact or castrated kids with sugar cane bagasse or elephant grass hay do not affect nutrient intake and performance. Feedlot goats have improved carcass traits if kept intact and fed elephant grass hay.

Antecedentes: Se requiere desarrollar nuevas estrategias de alimentación para producir carne de alta calidad en los sistemas actuales de producción de cabras. Objetivo: Evaluar el efecto de la castración y asociación de palma forrajera con bagazo de caña de azúcar o heno de pasto elefante sobre la ingesta de nutrientes, digestibilidad, rendimiento, comportamiento de alimentación y caracteristicas de la canal de cabritos de engorde. Métodos: Un total de 24 cabritos (12 castrados y 12 intactos) con peso inicial promedio de 18,5 ± 3,8 kg fueron asignados a un diseño factorial 2 x 2 completamente al azar (bagazo de caña de azucar o heno de pasto elefante; castrados o intactos) y confinados durante 70 días. Resultados: La ingesta de nutrientes y el rendimiento animal fueron similares entre tratamientos. El bagazo de caña de azúcar aumentó, en comparación con el heno de pasto elefante, la digestibilidad de la materia seca (66,12 vs 62,88; p=0,005), de la proteína cruda (74,26 vs 70,95; p=0,029) y de los carbohidratos no fibrosos (91,94 vs 83,07; p<0,001). La fuente de forraje afectó el tiempo de descanso, de rumia, y el tiempo total de masticación, pero no hubo efecto de la dieta sobre la eficiencia alimentacia y de la rumia. El heno de pasto elefante aumentó, en comparación con el bagazo, el peso de la canal caliente (9,87 vs 10,79; p=0,025) y el rendimiento de la canal caliente (43,81 vs 46,87; p=0,013). Los animales intactos produjeron canales calientes más pesadas en comparación con los castrados (10,80 vs 9,86; p=0,014). Conclusión: La alimentación de cabritos enteros o castrados con bagazo de caña de azúcar o heno de pasto elefante no afecta la ingesta de nutrientes y el rendimiento. Los cabritos tienen mejores características de canal si se alimentan con heno de pasto elefante y se dejan enteros.

Antecedentes: Novas estratégias de alimentação devem ser desenvolvidas para produção de carne de qualidade nos atuais sistemas de produção de caprinos. Objetivo: Avaliar o efeito da castração e da associação da palma forrageira com o bagaço de cana de açúcar ou feno de capim elefante no consumo de nutrientes, digestibilidade, desempenho, comportamento ingestivo e características de carcaça de cabritos confinados. Métodos: Um total de 24 caprinos (12 castrados e 12 não castrados), com peso inicial médio de 18,5 ± 3,8 kg, distribuídos em um delineamento experimental inteiramente casualizado, em arranjo fatorial 2 x 2 (bagaço de cana de açúcar ou feno de capim elefante; inteiros ou castrados), confinados durante 70 dias. Resultados: O consumo de nutrientes e o desempenho dos animais foram semelhante entre os tratamentos. O bagaço de cana elevou, quando comparado com o feno, a digestibilidade da matéria seca (66,12 vs 62,88; p=0,005), proteína (74,26 vs 70,95; p=0,029) e carboidratos não fibrosos (91,94 vs 83,07; p<0,001). As fontes de fibra afetaram os tempos de ócio, ruminação e mastigação total, mas não houve efeito para as eficiências de alimentação e ruminação. O feno de capim elefante aumentou, quando comparado com o bagaço, o peso de caracaça quente (9,87 vs 10,79; p=0,025) e o rendimento de carcaça quente (43,81 vs 46,87; p=0,013). Os animais inteiros produziram carcaças quentes mais pesadas em comparação aos castrados (10,80 vs 9,86; p=0,014). Conclusão: Alimentar caprinos inteiros ou castrados com bagaço de cana ou feno de capim-elefante não interfere no consumo de nutrientes e desempenho. Caprinos confinados terão as características de carcaça melhoradas se mantidos intactos e alimentados com feno de capim elefante.

RESUMO

ABSTRACT: There is limited information regarding both nitrogen (N) and energy partitioning of dairy cows grazing wellmanaged tropical pastures. The objective of this study was to investigate the N and energy partitioning of midlactation dairy cows on rotationally grazed elephant grass using two pregrazing targets: 95 % or maximum canopy light interception (LI95% or LIMax) during regrowth. The study used 26 Holstein × Jersey dairy cows arranged in a randomized complete block design with three 40day periods of sampling. Grazing at LI95% increased organic matter and crude protein intake by 20 % (p 0.05) which resulted in a 9 % increase in fat corrected milk yield (p 0.05) relative to LIMax. Cows grazing at LI95% had greater concentration of total volatile fatty acids, butyrate and valerate (p 0.05), and smaller acetate (p 0.05) than those grazing at LIMax. Intake of net energy for lactation (NEL) and NEL secreted in milk were greater (p 0.05), while partitioning of NEL towards maintenance tended to be greater (p = 0.07) for cows grazing at LI95% than those grazing at LIMax. Milk urea nitrogen and both urine and fecal N excretion were greater for cows grazing at LI95% (p 0.05), but N excretion intensity was lower than in cows grazing at LIMax (p 0.05). Strategic grazing management using the LI95% pregrazing target increases N losses through both urine and feces; however, it reduces N excretion intensity of dairy cows by 9 %.

RESUMO

There is limited information regarding both nitrogen (N) and energy partitioning of dairy cows grazing well­managed tropical pastures. The objective of this study was to investigate the N and energy partitioning of mid­lactation dairy cows on rotationally grazed elephant grass using two pre­grazing targets: 95 % or maximum canopy light interception (LI95% or LIMax) during regrowth. The study used 26 Holstein × Jersey dairy cows arranged in a randomized complete block design with three 40­day periods of sampling. Grazing at LI95% increased organic matter and crude protein intake by 20 % (p ≤ 0.05) which resulted in a 9 % increase in fat corrected milk yield (p ≤ 0.05) relative to LIMax. Cows grazing at LI95% had greater concentration of total volatile fatty acids, butyrate and valerate (p ≤ 0.05), and smaller acetate (p ≤ 0.05) than those grazing at LIMax. Intake of net energy for lactation (NEL) and NEL secreted in milk were greater (p ≤ 0.05), while partitioning of NEL towards maintenance tended to be greater (p = 0.07) for cows grazing at LI95% than those grazing at LIMax. Milk urea nitrogen and both urine and fecal N excretion were greater for cows grazing at LI95% (p ≤ 0.05), but N excretion intensity was lower than in cows grazing at LIMax (p ≤ 0.05). Strategic grazing management using the LI95% pre­grazing target increases N losses through both urine and feces; however, it reduces N excretion intensity of dairy cows by 9 %.

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There is limited information regarding both nitrogen (N) and energy partitioning of dairy cows grazing well–managed tropical pastures. The objective of this study was to investigate the N and energy partitioning of mid–lactation dairy cows on rotationally grazed elephant grass using two pre–grazing targets: 95 % or maximum canopy light interception (LI95% or LIMax) during regrowth. The study used 26 Holstein × Jersey dairy cows arranged in a randomized complete block design with three 40–day periods of sampling. Grazing at LI95% increased organic matter and crude protein intake by 20 % (p ≤ 0.05) which resulted in a 9 % increase in fat corrected milk yield (p ≤ 0.05) relative to LIMax. Cows grazing at LI95% had greater concentration of total volatile fatty acids, butyrate and valerate (p ≤ 0.05), and smaller acetate (p ≤ 0.05) than those grazing at LIMax. Intake of net energy for lactation (NEL) and NEL secreted in milk were greater (p ≤ 0.05), while partitioning of NEL towards maintenance tended to be greater (p = 0.07) for cows grazing at LI95% than those grazing at LIMax. Milk urea nitrogen and both urine and fecal N excretion were greater for cows grazing at LI95% (p ≤ 0.05), but N excretion intensity was lower than in cows grazing at LIMax (p ≤ 0.05). Strategic grazing management using the LI95% pre–grazing target increases N losses through both urine and feces; however, it reduces N excretion intensity of dairy cows by 9 %.

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The world population is expected to be larger and wealthier over the next few decades and will require more animal products, such as milk and beef. Tropical regions have great potential to meet this growing global demand, where pasturelands play a major role in supporting increased animal production. Better forage is required in consonance with improved sustainability as the planted area should not increase and larger areas cultivated with one or a few forage species should be avoided. Although, conventional tropical forage breeding has successfully released well-adapted and high-yielding cultivars over the last few decades, genetic gains from these programs have been low in view of the growing food demand worldwide. To guarantee their future impact on livestock production, breeding programs should leverage genotyping, phenotyping, and envirotyping strategies to increase genetic gains. Genomic selection (GS) and genome-wide association studies play a primary role in this process, with the advantage of increasing genetic gain due to greater selection accuracy, reduced cycle time, and increased number of individuals that can be evaluated. This strategy provides solutions to bottlenecks faced by conventional breeding methods, including long breeding cycles and difficulties to evaluate complex traits. Initial results from implementing GS in tropical forage grasses (TFGs) are promising with notable improvements over phenotypic selection alone. However, the practical impact of GS in TFG breeding programs remains unclear. The development of appropriately sized training populations is essential for the evaluation and validation of selection markers based on estimated breeding values. Large panels of single-nucleotide polymorphism markers in different tropical forage species are required for multiple application targets at a reduced cost. In this context, this review highlights the current challenges, achievements, availability, and development of genomic resources and statistical methods for the implementation of GS in TFGs. Additionally, the prediction accuracies from recent experiments and the potential to harness diversity from genebanks are discussed. Although, GS in TFGs is still incipient, the advances in genomic tools and statistical models will speed up its implementation in the foreseeable future. All TFG breeding programs should be prepared for these changes.

RESUMO

The objective of this study was to evaluate the BRS capiaçu grass silage combined with different hays of banana crop residue on fermentation profile, aerobic stability and nutritional value. The treatments consisted of elephant grass cv. BRS capiaçu (Pennisetum purpureum Schum.) ensiled with 37.44% banana peel hay, 36.06% banana pseudostem hay and 37.00% banana leaf hay, on a dry matter (DM) basis and control silage (no additive). The experimental design used was completely randomized, with five treatments and five replicates. Forage was collected when it reached 3.5 meters in height (90 days). Experimental PVC silos of known weight, 50 cm long, 10 cm diameter, were used for silage making. For all treatments, silage aerobic stability breakdown started after 64 hours exposure to air. The BRS capiaçu grass control silage or silage combined with pseudostem hay (mean of 73.15 kg t GM-1) presented effluent losses 40.46% higher than those observed for BRS capiaçu grass silage + banana leaf hay and 69.17% in relation the BRS capiaçu grass silage + banana peel hay. The inclusion of banana crop residue (hay) when ensiling BRS capiaçu grass decreased 13.93% gas losses compared to the control silage (mean of 3.11% DM). Higher values of total digestible nutrients, metabolizable energy and digestible energy content was found in BRS capiaçu grass silage + with banana peel hay. The greater in vitro dry matter digestibility and in vitro neutral detergent fiber digestibility was observed for BRS capiaçu grass silage combined with pseudostem hay. The inclusion of 37.44% banana peel hay improves the fermentation profile and aerobic stability of BRS capiaçu grass silage.(AU)

Ojetivou-se por meio desta pesquisa avaliar a silagem de capim-BRS capiaçu associada com diferentes fenos de resíduos da cultura da banana sobre o perfil fermentativo, estabilidade aeróbia e valor nutricional. Os tratamentos consistiram de capim-elefante cv. BRS capiaçu (Pennisetum purpureum Schum.) ensilado com 37,44% de feno de casca de banana, 36,06% de feno de pseudocaule de banana e 37,00% de feno de folha de bananeira, à base da matéria seca (MS), e a silagem controle (sem aditivo). O delineamento experimental utilizado foi inteiramente casualizado com cinco tratamentos e cinco repetições. A forragem foi coletada quando atingiu 3,5 metros de altura (90 dias). Para a produção da silagem, foram utilizados silos experimentais de PVC de peso conhecido, com 50 cm de comprimento e 10 cm de diâmetro. Para todos os tratamentos, a quebra da estabilidade aeróbia da silagem iniciou a partir de 64 horas de exposição ao ar. A silagem de BRS capiaçu controle ou associada ao feno de pseudocaule (média de 73,15 kg t MN-1) apresentaram perdas de efluentes 40,46% maiores do que as observadas para a silagem de BRS capiaçu associada ao feno de folha de bananeira e 69,17% em relação à silagem de BRS capiaçu associada à casca de banana. A inclusão dos resíduos da cultura da banana (feno) na ensilagem do capim- BRS capiaçu diminuiu 13,93% as perdas por gases em comparação com a silagem controle (média de 3,11% da matéria seca - MS). Maiores teores de nutrientes totais digestíveis, energia metabolizável e energia digestível foram verificadas na silagem de BRS capiaçu associada à casca de banana. A maior digestibilidade in vitro da matéria seca e da fibra em detergente neutro foi verificada na silagem de BRS capiaçu associada com feno de pseudocaule. A inclusão de 37,44% de feno de casca de banana melhora o perfil fermentativo e a estabilidade aeróbia da silagem de capim- BRS capiaçu.(AU)

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Abstract Background: Tropical grasses, such as elephant grass, have high moisture content during its ideal phenological state for silage. High moisture content hinders proper preservation and reduces the nutritive value of silage due to secondary fermentation and production of effluents. Adding feed materials with high dry matter content, such as murumuru (Astrocaryum murumuru) meal, is a potential alternative to improve silage yield. Objective: To determine the effects of including murumuru meal (0, 7, 14, 21, and 28%) on the fermentative characteristics, microbiological activity, aerobic stability, and chemical composition of elephant grass silages. Methods: A completely randomized design with five treatments and five replicates was used. Elephant grass was collected at 60 d of age, minced, and homogenized with murumuru meal. The mass was placed in experimental 15-L silos. The silos were collected and analyzed 45 d later. Results: Effluent production decreased (p<0.05) as the proportions of murumuru meal in silage increased. A quadratic effect (p<0.05) was observed on dry matter recovery. An increase (p<0.05) was observed in dry matter content, a decrease (p<0.05) in the neutral detergent fiber content, and an increase (p<0.05) in the non-fibrous carbohydrate content with the inclusion of murumuru meal. Conclusions: Addition of murumuru meal improves chemical composition and does not affect the fermentative characteristics of elephant grass silage, while it reduces effluent losses. Nevertheless, the inclusion of murumuru meal in the elephant grass silage decreased the time of aerobic stability.

Resumen Antecedentes: los pastos tropicales, tales como el pasto elefante, tienen alto contenido de humedad cuando están en su estado fenológico ideal para ensilar. Esto dificulta su adecuada preservación en el silo, reduciendo el valor nutritivo del ensilaje debido a fermentaciones secundarias y generación de efluentes. Una posible solución sería incluir materiales con alto contenido de materia seca, tales como la torta de murumuru (Astrocaryum murumuru). Objetivo: determinar el efecto de la inclusión de torta de murumuru (0; 7; 14; 21 y 28%) sobre las características fermentativas, microbiológicas, estabilidad aeróbica y composición química de los ensilajes de pasto elefante. Métodos: se utilizó un diseño completamente al azar, con cinco tratamientos y cinco repeticiones. El pasto elefante fue colectado a los 60 días de edad, luego picado y homogeneizado con la torta de murumuru. La masa fue colocada en silos experimentales con capacidad de 15 L. Luego de 45 días de ensilado, los silos fueron abiertos y las muestras fueron colectadas para su posterior análisis. Resultados: hubo reducción (p<0,05) en la producción de efluentes a medida que se incrementó la proporción de torta de murumuru en el ensilado. Se observó un efecto cuadrático (p<0,05) en la recuperación de materia seca. Hubo aumento (p<0,05) en los contenidos de materia seca con la adición de torta de murumuru. Se observó disminución (p<0,05) en el contenido de fibra detergente neutra y aumento (p<0,05) de carbohidratos no fibrosos. Conclusión: La adición de torta de murumuru mejora la composición química, reduce las perdidas por efluentes y no afecta las características fermentativas de ensilado de pasto elefante. Sin embargo, la inclusión de la torta de murumuru en el ensilado de pasto elefante disminuye el tiempo en estabilidad aeróbica.

Resumo Antecedentes: capins tropicais, como por exemplo o capim-elefante apresentam alto teor de umidade quando possuem produtividade compatível e estão no estádio fenológico adequado para ensilagem. Isso dificulta a adequada preservação no silo, ocasionando a redução do valor nutritivo da silagem devido a fermentações secundárias e a produção de efluentes. Uma possível solução seria o uso de aditivos com alto teor de matéria seca, como bolo de murumuru (Astrocaryum murumuru). Objetivo: determinar o efeito da inclusão da torta de murumuru (0; 7; 14; 21 e 28%) na ensilagem de capim-elefante sobre as características fermentativas, microbiológicas, estabilidade aeróbia e a composição química das silagens. Métodos: utilizou- se um delineamento inteiramente casualizado, com cinco tratamentos e cinco repetições. O capim-elefante foi colhido aos 60 dias de idade, o mesmo foi picado e homogeneizado à torta de murumuru. A massa foi ensilada em silos experimentais com capacidade de 15 L. Após 45 dias de ensilagem, os silos foram abertos e amostras foram coletadas para posteriores análises laboratoriais. Resultados: houve redução (p<0,05) na produção de efluentes à medida que se elevaram as proporções da torta de murumuru na ensilagem. Observou-se efeito quadrático (p<0,05) na recuperação de matéria seca. Houve aumento (p<0,05) nos teores de matéria seca com a adição da torta murumuru. Observou-se diminuição (p<0,05) nos teores de fibra em detergente neutro e aumento (p<0,05) nos teores de carboidratos não fibrosos. Conclusão: torta de murumuru como aditivo melhora a composição química, reduz perdas principalmente por efluente e não afeta as características fermentativas de silagens de capim- elefante. Entretanto, a inclusão da torta de murumuru na ensilagem de capim-elefante diminui o tempo em estabilidade aeróbia.

RESUMO

The objective of this study was to evaluate the association of pseudostem hay of banana trees of different roughages in the diet of F1 Holstein/Zebu cows on their nutrient intake and digestibility, nitrogen balance, microbial synthesis, ingestive behavior, and milk production. The experiment was distributed in two simultaneous 4 × 4 Latin squares. The treatments were as follows: diet 1-sorghum silage as exclusive dietary roughage; diet 2-sorghum silage (70%) associated with 30% pseudostem hay of banana trees (dry matter basis); diet 3-70% elephant grass with 30% pseudostem hay of banana trees (dry matter basis); and diet 4-70% sugarcane with 30% banana pseudostem hay (dry matter basis). The roughage/concentrate ratio was 75:25. The animals fed with sorghum silage presented 14.45% higher intake (p = 0.01) to that of animals fed hay and elephant grass. The diets containing silage and silage with hay showed digestibility of neutral detergent fiber corrected for ash and protein that was 57.75% higher (p < 0.01) than that of other diets. Cows fed elephant grass spent more time intake (p = 0.01). Diets did not influence milk yield (p = 0.47), and the milk yield corrected for 3.5 fat (p = 0.22), final weight (p = 0.06), and intake efficiency (p = 0.57), presenting a mean of 14.16 kg/day, 15.94 kg/day, 590 kg, and 0.9 kg of milk/kg of ingested dry matter, respectively. The utilization of pseudostem hay associated with other roughage can be an alternative to milk yield in F1 Holstein/Zebu cows.

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The objective was to estimate the growth indexes of elephant grass cv. Roxo managed under rainfed conditions in different growing seasons. Seven growth ages (9, 18, 27, 36, 45, 54, and 63 days) were evaluated in three growing seasons (rainy, transition and dry). A completely randomised design was adopted, with split-plot arrangement with time repeated measures, with the ages being the plots and the seasons the subplots. Interaction of age x season was observed. The specific leaf area mean was 0.0286 ± 0.0039 during the rainy season. In the transition season, it adjusted to a third-degree polynomial model; in the dry season it declined linearly (0.0003 m2 g-1). The leaf weight ratio adjusted to the third-degree polynomial model in the rainy and dry seasons, and in the transition season it was maximised at 28 DAC (0.694 g g-1). The leaf area ratio continuously declined in the rainy season. In the transition and dry seasons, it adjusted to the third-degree polynomial model. The net assimilation rate presented averages of 3.73 ± 2.50 and 3.63 ± 1.48 g m-2 day-1 in the rainy and transition seasons, respectively. In the dry season, it was minimised at 48.4 days. The relative growth rate mean was 0.0075 ± 0.0037 during the rainy season. In the transition and dry seasons, it adjusted to the third-degree polynomial model. The growth index rates of elephant grass cv. Roxo are modified by growing seasons, and the pattern and magnitude of the response varies throughout the growth cycle.

Objetivou-se estimar os índices de crescimento do capim-elefante cv. Roxo manejado sob sequeiro em diferentes épocas de cultivo. Analisaram-se sete idades de crescimento (9; 18; 27; 36; 45; 54 e 63 dias) em três épocas de cultivo (chuvosa, transição e seca). Adotou-se delineamento inteiramente casualizado em arranjo de parcelas subdivididas no tempo, com as idades sendo alocadas nas parcelas e as épocas de cultivo nas subparcelas. Constatou-se interação idade x época de cultivo. A área foliar específica revelou média de 0,0286 ± 0,0039 na época chuvosa. Na época de transição ajustou-se ao modelo polinomial de terceiro grau e na época seca reduziu linearmente (0,0003 m2 g-1). A razão de peso foliar ajustou-se ao modelo polinomial de terceiro grau nas épocas chuvosa e seca e na época de transição foi maximizada aos 28 DAC (0,694 g g-1). A razão de área foliar reduziu continuamente na época chuvosa. Já nas épocas de transição e seca ajustou-se ao modelo polinomial de terceiro grau. A taxa de assimilação líquida apresentou médias de 3,73 ± 2,50 e 3,63 ± 1,48 g m-2 dia-1 para as épocas chuvosa e de transição, respectivamente. Na época seca, foi minimizada aos 48,4 dias. A taxa de crescimento relativo apresentou média de 0,0075 ± 0,0037 na época chuvosa. Nas épocas de transição e seca ajustou-se ao modelo polinomial de terceiro grau. Os índices de crescimento do capim-elefante cv. Roxo são modificados pelas épocas de cultivo e o padrão e a magnitude da resposta variam ao longo do ciclo de crescimento.

Assuntos

RESUMO

The objective was to estimate the growth indexes of elephant grass cv. Roxo managed under rainfed conditions in different growing seasons. Seven growth ages (9, 18, 27, 36, 45, 54, and 63 days) were evaluated in three growing seasons (rainy, transition and dry). A completely randomised design was adopted, with split-plot arrangement with time repeated measures, with the ages being the plots and the seasons the subplots. Interaction of age x season was observed. The specific leaf area mean was 0.0286 ± 0.0039 during the rainy season. In the transition season, it adjusted to a third-degree polynomial model; in the dry season it declined linearly (0.0003 m2 g-1). The leaf weight ratio adjusted to the third-degree polynomial model in the rainy and dry seasons, and in the transition season it was maximised at 28 DAC (0.694 g g-1). The leaf area ratio continuously declined in the rainy season. In the transition and dry seasons, it adjusted to the third-degree polynomial model. The net assimilation rate presented averages of 3.73 ± 2.50 and 3.63 ± 1.48 g m-2 day-1 in the rainy and transition seasons, respectively. In the dry season, it was minimised at 48.4 days. The relative growth rate mean was 0.0075 ± 0.0037 during the rainy season. In the transition and dry seasons, it adjusted to the third-degree polynomial model. The growth index rates of elephant grass cv. Roxo are modified by growing seasons, and the pattern and magnitude of the response varies throughout the growth cycle.(AU)

Objetivou-se estimar os índices de crescimento do capim-elefante cv. Roxo manejado sob sequeiro em diferentes épocas de cultivo. Analisaram-se sete idades de crescimento (9; 18; 27; 36; 45; 54 e 63 dias) em três épocas de cultivo (chuvosa, transição e seca). Adotou-se delineamento inteiramente casualizado em arranjo de parcelas subdivididas no tempo, com as idades sendo alocadas nas parcelas e as épocas de cultivo nas subparcelas. Constatou-se interação idade x época de cultivo. A área foliar específica revelou média de 0,0286 ± 0,0039 na época chuvosa. Na época de transição ajustou-se ao modelo polinomial de terceiro grau e na época seca reduziu linearmente (0,0003 m2 g-1). A razão de peso foliar ajustou-se ao modelo polinomial de terceiro grau nas épocas chuvosa e seca e na época de transição foi maximizada aos 28 DAC (0,694 g g-1). A razão de área foliar reduziu continuamente na época chuvosa. Já nas épocas de transição e seca ajustou-se ao modelo polinomial de terceiro grau. A taxa de assimilação líquida apresentou médias de 3,73 ± 2,50 e 3,63 ± 1,48 g m-2 dia-1 para as épocas chuvosa e de transição, respectivamente. Na época seca, foi minimizada aos 48,4 dias. A taxa de crescimento relativo apresentou média de 0,0075 ± 0,0037 na época chuvosa. Nas épocas de transição e seca ajustou-se ao modelo polinomial de terceiro grau. Os índices de crescimento do capim-elefante cv. Roxo são modificados pelas épocas de cultivo e o padrão e a magnitude da resposta variam ao longo do ciclo de crescimento.(AU)

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RESUMO

Objective: This study ascertained effects of cactus pear in association with different roughage in the diet of F1 Holstein/Zebu cows on intake, nutrient digestibility, nitrogen balance, ingestive behavior and performance. Methods: Eight cows with 72 ± 11 days of lactation were used. The experimental design was simultaneous in two 4 x 4 Latin squares. Four experimental diets were used: Diet 1 - sorghum silage as exclusive roughage; Diet 2 - sorghum silage associated with cactus pear in a proportion of 50% of the roughage (dry basis); Diet 3 - elephant grass (Pennisetum purpureum cv. Roxo) as exclusive roughage; Diet 4 - elephant grass associated with cactus pear in a proportion of 50% of the roughage. The roughage:concentrate ratio was 75:25. Dry matter intake (P = 0.01) was higher with sorghum silage. Results: There were differences in dry matter intake (P = 0.01), crude protein (P <0.01), ether extract (P = 0.01), non-fibrous carbohydrates (P <0.01) and total digestible nutrients (P = 0.01) among the diets. Cactus pear in the diet reduced water intake by 44.52% (P < 0.01). The nitrogen balance was 59.71% and 27.49% lower in animals treated with exclusive sorghum silage and sorghum silage associated with cactus pear in relation to diets with elephant grass and elephant grass associated with cactus pear, respectively (P < 0.01). The diets did not influence the milk production (P = 0.70), 3.5% fat corrected milk production (P = 0.72) or feed efficiency (P = 0.61). Conclusion: The association of cactus pear with sorghum or elephant grass silage does not alter milk production, reduces the intake of dry matter and water and improves the digestibility of nutrients.

RESUMO

Biomass has attracted considerable attention as energy, economic, and environmental asset, as result of its abundance and range of properties. The use of mesoporous catalysts during fast pyrolysis has been a highly important route to improve efficiency as well adding value to biomass. The addition of titanium to molecular sieves increases the efficiency of the pyrolysis reaction by improving production and selectivity of products of interest. This study aims at analyzing the catalytic pyrolysis products of elephant grass using titanium catalysts prepared at different Si/Ti molar ratios, i.e., 25 and 50. The material was supported on MCM-41 for the catalytic pyrolysis of biomass. The biomass pyrolysis reactions were performed in a micropyrolyzer coupled to a GC/MS analyzer. The Ti-MCM-41 samples were characterized by XRD, BET-specific area, and UV-visible. The distribution of pyrolysis products depended on process parameters such as temperature and catalyst type. The highest yield for hydrocarbon production, such as styrene, benzene, methylbenzene, and naphthalene, was observed at 600 °C using Si/Ti equal to 50.

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RESUMO

The objective of this study was to evaluate the macronutrient accumulations in leaf, stem, and shoot of elephant grass cv. Roxo. The treatments consisted of seven growth ages (9, 18, 27, 36, 45, 54, and 63 days) and three growing seasons (rainy, transition, and dry). A completely randomized design and a split-plot time arrangement were used, where the ages were the plots and the seasons the subplots, with three replications. Interaction between the factors age and season of cultivation for the contents and the daily accumulation rates of N, P, K, Ca, Mg, and S in leaf, stem, and shoot fractions were calculated. The margins of daily accumulation of nutrients N, P, K, Mg, and S presented positive linear behavior in all seasons studied; however, with variation in the magnitude of the response between them. The daily accumulation rate of Ca in the canopy was adjusted to a linear model for the rainy and dry seasons and to a quadratic model for the transition season, reaching a maximum of 4.60 kg ha-1 at 59.76 days of growth. The accumulation of nutrients in elephant grass cv. Roxo showed the following decreasing order: K > N > P > Mg > Ca > S in the rainy and transition seasons, while in the dry season the following decreasing order was observed: K > P > N > Ca > Mg > S.(AU)

Objetivou-se avaliar a marcha de acúmulo de macronutrientes na folha, colmo e na parte aérea do capim-elefante cv. Roxo. Os tratamentos consistiram em sete idades de crescimento (9; 18; 27; 36; 45; 54 e 63 dias) em três períodos de cultivo (chuvoso, de transição e seco). Adotou-se um delineamento inteiramente casualizado e um arranjo de parcelas subdivididas no tempo, onde as idades foram alocadas nas parcelas e os períodos de cultivo nas subparcelas, com três repetições. Constatou-se interação entre os fatores idade e período de cultivo para os teores e para as taxas de acúmulo diário de N, P, K, Ca, Mg e S nas frações folha, colmo e parte aérea. As marchas de acúmulo diário dos nutrientes N, P, K, Mg e S apresentaram comportamento linear positivo para todos os períodos estudados, todavia com variação na magnitude da resposta entre estes. A taxa de acúmulo diário de Ca na parte aérea do dossel ajustou-se ao modelo linear para os períodos chuvoso e seco e ao modelo quadrático para o período de transição, atingindo máximo de 4,60 kg ha-1 aos 59,76 dias de crescimento. O acúmulo dos nutrientes no capim-elefante cv. Roxo apresentou a seguinte ordem decrescente: K > N > P > Mg > Ca > S no período chuvoso e de transição enquanto no período seco observou-se a seguinte ordem decrescente: K > P > N > Ca > Mg> S.(AU)

Assuntos

RESUMO

The objective of this study was to evaluate the macronutrient accumulations in leaf, stem, and shoot of elephant grass cv. Roxo. The treatments consisted of seven growth ages (9, 18, 27, 36, 45, 54, and 63 days) and three growing seasons (rainy, transition, and dry). A completely randomized design and a split-plot time arrangement were used, where the ages were the plots and the seasons the subplots, with three replications. Interaction between the factors age and season of cultivation for the contents and the daily accumulation rates of N, P, K, Ca, Mg, and S in leaf, stem, and shoot fractions were calculated. The margins of daily accumulation of nutrients N, P, K, Mg, and S presented positive linear behavior in all seasons studied; however, with variation in the magnitude of the response between them. The daily accumulation rate of Ca in the canopy was adjusted to a linear model for the rainy and dry seasons and to a quadratic model for the transition season, reaching a maximum of 4.60 kg ha-1 at 59.76 days of growth. The accumulation of nutrients in elephant grass cv. Roxo showed the following decreasing order: K > N > P > Mg > Ca > S in the rainy and transition seasons, while in the dry season the following decreasing order was observed: K > P > N > Ca > Mg > S.

Objetivou-se avaliar a marcha de acúmulo de macronutrientes na folha, colmo e na parte aérea do capim-elefante cv. Roxo. Os tratamentos consistiram em sete idades de crescimento (9; 18; 27; 36; 45; 54 e 63 dias) em três períodos de cultivo (chuvoso, de transição e seco). Adotou-se um delineamento inteiramente casualizado e um arranjo de parcelas subdivididas no tempo, onde as idades foram alocadas nas parcelas e os períodos de cultivo nas subparcelas, com três repetições. Constatou-se interação entre os fatores idade e período de cultivo para os teores e para as taxas de acúmulo diário de N, P, K, Ca, Mg e S nas frações folha, colmo e parte aérea. As marchas de acúmulo diário dos nutrientes N, P, K, Mg e S apresentaram comportamento linear positivo para todos os períodos estudados, todavia com variação na magnitude da resposta entre estes. A taxa de acúmulo diário de Ca na parte aérea do dossel ajustou-se ao modelo linear para os períodos chuvoso e seco e ao modelo quadrático para o período de transição, atingindo máximo de 4,60 kg ha-1 aos 59,76 dias de crescimento. O acúmulo dos nutrientes no capim-elefante cv. Roxo apresentou a seguinte ordem decrescente: K > N > P > Mg > Ca > S no período chuvoso e de transição enquanto no período seco observou-se a seguinte ordem decrescente: K > P > N > Ca > Mg> S.

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RESUMO

This study was carried out aiming to evaluate the biomass components of elephant grass cv. Roxo at seven growth ages, during rainy, transition and dry seasons. A completely randomized design was adopted with a split plot arrangement over time. The treatments consisted of seven growth ages (9, 18, 27, 36, 45, 54 and 63) and three seasons (rainy, transition and dry). The variables green forage biomass, dead forage biomass, green stem biomass and green leaf blade biomass showed positive linear responses to age and had their magnitude influenced by the evaluated seasons. The live/dead material ratio showed a decreasing linear response as a function of age. The leaf blade/stem ratio showed a negative linear adjustment in the rainy season, reaching a critical value of 1.0 at 59 days, and it showed a quadratic adjustment in the transition season, with the maximum point at 27.53 days; however, this ratio was not influenced by age in the dry season, revealing an average value of 2.22 ± 0.27. The canopy height and leaf area index showed a positive linear response to age in the three seasons. Tiller population density showed quadratic behaviour for age, with maximum estimated values of 134 and 110 til. m-2 at 31.24 and 37.40 days in the rainy and dry seasons, respectively. Rainfall seasonality influences the magnitude of the daily increase of the distinct biomass components of Pennisetum purpureum cv. Roxo.

Objetivou-se avaliar os componentes da biomassa em capim-elefante cv. Roxo em sete idades de crescimento, nas épocas chuvosa, transição e seca. Adotou-se um delineamento inteiramente casualizado, em arranjo de parcelas subdivididas no tempo. Os tratamentos consistiram em sete idades de crescimentos (9; 18; 27; 36; 45; 54 e 63 dias) e três épocas (chuvosa, transição e seca). As variáveis biomassa de forragem verde, forragem morta, colmo verde e de lâmina foliar verde apresentaram resposta linear positiva para o fator idade e tiveram suas magnitudes influenciadas pelas épocas de avaliação. A relação material vivo/material morto respondeu de forma linear decrescente em função das idades. A relação lâmina foliar/colmo apresentou ajuste linear negativo na época chuvosa, atingindo valor crítico de 1,0 aos 59 dias e ajuste quadrático na época de transição, com ponto de máxima aos 27,53 dias, e não foi influenciada pelo fator idade na época seca, com valor médio de 2,22±0,27. A altura do dossel e o índice de área foliar responderam de forma linear positiva para o fator idade, nas três épocas. A densidade populacional de perfilhos apresentou comportamento quadrático para o fator idade, com valores máximos estimados em 134 e 110 perf. m-2 aos 31,24 e 37,40 dias de idade nas épocas chuvosa e seca, respectivamente. A sazonalidade da precipitação pluvial influencia a magnitude do incremento diário nos distintos componentes da biomassa em Pennisetum purpureum cv. Roxo.

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RESUMO

This study was carried out aiming to evaluate the biomass components of elephant grass cv. Roxo at seven growth ages, during rainy, transition and dry seasons. A completely randomized design was adopted with a split plot arrangement over time. The treatments consisted of seven growth ages (9, 18, 27, 36, 45, 54 and 63) and three seasons (rainy, transition and dry). The variables green forage biomass, dead forage biomass, green stem biomass and green leaf blade biomass showed positive linear responses to age and had their magnitude influenced by the evaluated seasons. The live/dead material ratio showed a decreasing linear response as a function of age. The leaf blade/stem ratio showed a negative linear adjustment in the rainy season, reaching a critical value of 1.0 at 59 days, and it showed a quadratic adjustment in the transition season, with the maximum point at 27.53 days; however, this ratio was not influenced by age in the dry season, revealing an average value of 2.22 ± 0.27. The canopy height and leaf area index showed a positive linear response to age in the three seasons. Tiller population density showed quadratic behaviour for age, with maximum estimated values of 134 and 110 til. m-2 at 31.24 and 37.40 days in the rainy and dry seasons, respectively. Rainfall seasonality influences the magnitude of the daily increase of the distinct biomass components of Pennisetum purpureum cv. Roxo.(AU)

Objetivou-se avaliar os componentes da biomassa em capim-elefante cv. Roxo em sete idades de crescimento, nas épocas chuvosa, transição e seca. Adotou-se um delineamento inteiramente casualizado, em arranjo de parcelas subdivididas no tempo. Os tratamentos consistiram em sete idades de crescimentos (9; 18; 27; 36; 45; 54 e 63 dias) e três épocas (chuvosa, transição e seca). As variáveis biomassa de forragem verde, forragem morta, colmo verde e de lâmina foliar verde apresentaram resposta linear positiva para o fator idade e tiveram suas magnitudes influenciadas pelas épocas de avaliação. A relação material vivo/material morto respondeu de forma linear decrescente em função das idades. A relação lâmina foliar/colmo apresentou ajuste linear negativo na época chuvosa, atingindo valor crítico de 1,0 aos 59 dias e ajuste quadrático na época de transição, com ponto de máxima aos 27,53 dias, e não foi influenciada pelo fator idade na época seca, com valor médio de 2,22±0,27. A altura do dossel e o índice de área foliar responderam de forma linear positiva para o fator idade, nas três épocas. A densidade populacional de perfilhos apresentou comportamento quadrático para o fator idade, com valores máximos estimados em 134 e 110 perf. m-2 aos 31,24 e 37,40 dias de idade nas épocas chuvosa e seca, respectivamente. A sazonalidade da precipitação pluvial influencia a magnitude do incremento diário nos distintos componentes da biomassa em Pennisetum purpureum cv. Roxo.(AU)

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Law 12305/10, National Solid Waste Policy of Brazil, banned the disposal in landfills of any solid waste that could be converted to another use. Sludge produced at Industrial Wastewater Treatment Plants, which contains components characteristic of fertilizers, falls into this category. This type of sludge, also known as a biosolid, has great potential to replace commercial chemical fertilization. The use of biosolids in agriculture allows for compliance with new legislation, reducing the burden on landfills and reusing a waste product. The present paper utilizes the life cycle assessment methodology to compare the carbon footprint associated with the use of different quantities of biosolid and selected chemical fertilizers in the production of elephant grass. The IPCC 2013 GWP 100a method, which is based on data published by the Intergovernmental Panel on Climate Change, was selected as the environmental assessment method. The method expresses the emissions of greenhouse gases generated, in kilograms of CO2 equivalent, over a time horizon of 100 years. The biosolid quantities used were based on the Brazilian Environment Council Resolution 375. The chemical fertilizer used contained urea, simple superphosphate, and potassium chloride. The use of biosolids in the amounts calculated according to Brazilian standards resulted in a carbon footprint approximately 17.7% lower than the use of the chemical fertilization mix, with similar productivity in both cases. The transportation of biosolids to the experimental area was responsible for the majority of emissions associated with the use of biosolids. Urea synthesis was the largest contributor to emissions resulting from the use of commercial chemical fertilizer, accounting for 73.6% of total emissions.

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The influence of process conditions (rotary speed/temperature) on the performance of a rotary kiln reactor for non-catalytic pyrolysis of a perennial grass (elephant grass) was investigated. The product yields, the production of non-condensable gases as well as the biochar properties were evaluated. The maximum H2 yield was close to that observed for catalytic pyrolysis processes, while the bio-oil yield was higher than reported for pyrolysis of other biomass in rotary kiln reactors. A H2/CO ratio suitable for Fischer-Tropsch synthesis (FTS) was obtained. The biochars presented an alkaline pH (above 10) and interesting contents of nutrients, as well as low electrical conductivity, indicating a high potential as soil amendment.

Assuntos