MORFOGÊNESE, CARACTERÍSTICAS ESTRUTURAIS E ACÚMULO DE FORRAGEM EM PASTAGEM DE Cynodon dactylon, EM DIFERENTES ESTACÕES DO ANO

Foram avaliadas as características morfogênicas e estruturais e o acúmulo de biomassa foliar em uma pastagem de capim-coastcross-1, manejada sob lotação rotacionada com vacas em lactação, nas estações do ano. As avaliações foram feitas em outubro–novembro de 2000 (primavera) e fevereiro–março (verão), maio–junho (outono) e julho–agosto de 2001 (inverno), segundo o delineamento de blocos casualizados, com seis repetições. Durante o período de descanso do piquete, foram identificados perfilhos para observações do alongamento, aparecimento e senescência foliares. A densidade de perfilhos foi estimada por respectiva contagem em área de 0,09 m2. A taxa de acúmulo de biomassa foliar foi obtida multiplicando-se o acúmulo/perfilho pela densidade de perfilhos. A taxa de alongamento foliar foi maior no verão, enquanto a taxa de aparecimento foliar e o número de folhas/perfilho, na primavera. O número de perfilhos não variou com a estação (valor médio de 2.770/m2). O acúmulo de biomassa senescente foi proporcional ao acúmulo de biomassa de folhas. A taxa de acúmulo de folhas foi maior no verão e apresentou estreita relação com a taxa de alongamento de folhas. O uso da taxa de alongamento foliar e da densidade de perfilhos, para obtenção das taxas de acúmulo de biomassa foliar, superestimou os valores. PALAVRAS-CHAVE: Alongamento foliar, aparecimento foliar, perfilhamento, producão de forragem, senescência.

Agronomic characteristics and nutritive value of elephant grass clones managed under rotational stocking during the dry period

This study aimed to evaluate the agronomic characteristics and nutritional value of two clones of elephant grass (CNPGL 00-1-3 and BRS Kurumi) operating under rotational stocking in the dry season. A completely randomized design with repeated measures (grazing cycles) and three replicates (paddocks) was used. Clones were managed under rotational stocking with a defoliation interval of 24 days and four days of occupation of paddocks, using Holstein x Gyr heifers with mean body weight of 150 kg. The evaluations were conducted in April/May, May/June, June/July and July/August 2010. Green forage mass was influenced by clone and grazing cycle, with higher mean value observed for CNPGL 03-01-00, which was 17% higher than the value observed for BRS Kurumi, and there was decreased of dry mass of green forage with the advance of grazing cycles. Leaf mass was influenced only by grazing cycle, with gradual reduction from the first to the third cycle. However, in fourth cycle was increase in biomass of leaves, which did not differ from that observed in the second cycle. There was interaction for dry matter production of stem, being observed differences in the first and third cycles for the clones. There was no effect of the factors studied for the production of senescent material. The leaf:stem ratio was influenced by grazing cycles, with interaction of the factors studied. The clone BRS Kurumi kept the leaf:stem ratio stable over the cycles, while clone CNPGL 1-3-00 presented a decrease in leaf:stem ratio from first until to third cycle. The content of crude protein (PB) was not influenced by the factors studied, with average values of 15.3% and 15.8% PB for the CNPGL 00-1-3 and BRS Kurumi clones. Neutral detergent fiber (NDF) and the in vitro dry matter digestibility (IVDMD) were affected only by grazing cycles. The highest values of NDF were observed in the three first grazing cycles, with values of 55.5%, 56.0% and 55.7% from the first to the third grazing cycle, respectively, while in the fourth cycle was obtained the value of 50.5%. There was a decrease in the IVDMD until the third cycle. In the fourth cycle the IVDMD values were similar to the first cycle. The clones did not differ in relation to biomass production, morphological composition and nutritional value, during the dry season

Morphogenesis and leaf biomass accumulation in elephantgrass sward evaluated at diferent period of the year

O objetivo deste trabalho foi avaliar o efeito da época do ano nas características morfogênicas e estruturais e no acúmulo de biomassa foliar de uma pastagem de capim-elefante (Pennisetum purpureum Schum.). Vacas mestiças Holandês x Zebu foram manejadas segundo o método de pastejo com lotação rotacionada com três dias de ocupação e 30 dias de descanso. Foi usado delineamento em blocos casualizados com seis repetições. As avaliações foram realizadas em fevereiro/março, abril/maio, julho/agosto e outubro de 2001. As maiores taxas de alongamento e aparecimento de folhas ocorreram durante fevereiro/março. Os perfilhos aéreos superaram os basilares em quantidade, mas apresentaram menores taxas de alongamento (5,1 versus 9,8 cm/dia/perfilho), aparecimento (0,13 versus 0,16 folhas/dia/perfilho) e senescência (0,9 versus 1,3 cm/dia/perfilho) foliares. As produções e taxas de acúmulo de biomassa foliar foram maiores durante fevereiro/março e apresentaram estreita relação com as variáveis morfogênicas. Os perfilhos aéreos contribuíram, em média, com 63% da biomassa foliar do capim-elefante.The objective of this work was to evaluate the effect of the time of the year on morphogenetic and structural traits and leaf biomass accumulation of elephantgrass (Pennisetum purpureum Schum.). The sward was managed in a rotational stocking method with lactacting cows with 30 days of resting period and three days of paddock occupation. A randomized block and six replicates were used. Evaluations were carried out at February/March, April/May, July/August and October of 2001. Higher values of leaf appearance and expansion rates were observed during the February/March period. Although the aerial tiller density was greater than the basal one, they showed lower leaf expansion (5.1 versus 9.8 cm/day/tiller), appearance (0.13 versus 0.16 leaves/day/tiller) and senescence (0.9 versus 1.3 cm/day/tiller) rates. The forage mass production and accumulation rates of leaf biomass were higher during February/March period and showed strong relationship with pasture morphogenetic traits. The aerial tillers contributed, in average, with 63% of total elephantgrass leaf biomass

Comparative efficacy of the conventional and automated methods for determining neutral and acid detergent fiber

Different methods are available to determine fiber content in feeds. However, information about the accuracy of this methods for neutral detergent fiber (NDF) and acid detergent fiber ADF contents estimation (obtained with the use of TNT-100 nylon filtering bags) is very limited related to the large number of ruminant feed analysis. The purpose of this study was to compare the efficacy of the automated and conventional Van Soest methods to determine NDF and ADF contents for bovine cattle and feed supplements. Four classes of samples (tropical forage, maize silage hybrid, concentrated supplements and bovine cattlecattle) were evaluated for NDF and ADF contents using conventional and automated methods. Analysis involved a hierarchical factorial scheme with an entirely randomized design executed with repetitions. It was concluded that the automated method procedure generated similar results when compared to the conventional method for the determination of NDF contents in tropical forage, bovine cattle and maize silage samples, although is not recommended for samples with a high starch content. This system was not efficient for ADF determination in the evaluated samples.Different methods are available to determine fiber content in feeds. However, information about the accuracy of this methods for neutral detergent fiber (NDF) and acid detergent fiber ADF contents estimation (obtained with the use of TNT-100 nylon filtering bags) is very limited related to the large number of ruminant feed analysis. The purpose of this study was to compare the efficacy of the automated and conventional Van Soest methods to determine NDF and ADF contents for bovine cattle and feed supplements. Four classes of samples (tropical forage, maize silage hybrid, concentrated supplements and bovine cattlecattle) were evaluated for NDF and ADF contents using conventional and automated methods. Analysis involved a hierarchical factorial scheme with an entirely randomized design executed with repetitions. It was concluded that the automated method procedure generated similar results when compared to the conventional method for the determination of NDF contents in tropical forage, bovine cattle and maize silage samples, although is not recommended for samples with a high starch content. This system was not efficient for ADF determination in the evaluated samples

Milk fatty acid profile of cows grazing elephant grass BRS Kurumi pasture with and without energy supplementation

This study evaluated the effects of energy supplementation on the intake and milk fatty acid composition of cows grazing BRS Kurumi elephant grass pasture during the rainy season. Two treatments (with and without supplementation) were evaluated using a switchback design with six Holstein × Gyr dairy cows after the peak of lactation. The average milk yield, body weight, and days in milk of the cows at the beginning of the study were 18.0±2.89 kg day−1, 560±66 kg, and 99±12, respectively. The evaluations were performed over three grazing cycles, with adaptation periods of 14 days and six days of sampling. In the energy supplementation treatment, each cow received 3 kg day−1 of ground corn (as-fed basis), with 2 kg day−1 at the morning milking and 1 kg day−1 at the afternoon milking. The ground corn presented 87.5% dry matter, 7.3% crude protein, 5.1% ether extract, and 85% of total digestible nutrients. The cows supplemented with ground corn consumed more oleic (+567%) and linoleic (+88%) acids. Unsupplemented cows consumed 26% more α-linolenic acid and produced milk with more oleic (+10%), vaccenic (+23%), and rumenic (+21%) acids, and less (−7%) pro-atherogenic fatty acids (lauric + myristic + palmitic acids). Milk fat from unsupplemented cows showed better nutritional quality, with lower atherogenicity and thrombogenicity indices and a higher hypo/hypercholesterolemic fatty acid ratio

Morphophysiology and nutritive value of signalgrass under natural shading and full sunlight

O objetivo deste trabalho foi avaliar características morfofisiológicas e o valor nutritivo da Brachiaria decumbens, nas épocas chuvosas de 2003 e 2004, em um sistema silvipastoril, com faixas de 30 m de largura com essa gramínea, alternadas com faixas de 10 m com árvores de Acacia mangium, A. angustissima, Mimosa artemisiana, Leucaena leucocephala x L. diversifolia, Eucalyptus grandis. Foi adotado o delineamento de blocos ao acaso, em parcelas subsubdivididas (características morfofisiológicas) ou parcelas subdivididas (características do valor nutritivo), com quatro repetições. Em 2003, o sombreamento foi de 65% da radiação incidente fora do bosque e, em 2004, de 35%, depois da retirada de árvores de eucalipto. Sob sombreamento, a densidade de perfilhos, o índice de área foliar e a massa de forragem foram maiores no segundo ano. Os teores médios de fibra em detergente neutro (FDN) foram maiores a pleno sol que sob sombreamento, enquanto os valores médios de proteína bruta (PB) e a digestibilidade in vitro da matéria seca foram maiores à sombra. O sombreamento moderado aumenta os teores de PB, reduz os teores de FDN e incrementa a digestibilidade da forragem de gramíneas que crescem sob a copa das árvores.The objective of this trial was to evaluate the morphophysiological traits and nutritive value of Brachiaria decumbens, during 2003 and 2004 rainy seasons, in a silvopastoral system, with grass alone (30 m width), alternated with grass plus trees (Acacia mangium, A. angustissima, Mimosa arthemisiana, Leucaena leucocephala x L. diversifolia, Eucalyptus grandis) strips (10 m width). The experimental design was a randomized block arranged in a split plot design (morphophysiological traits) or split-split plot (nutritive value traits), and replicated four times. The level of shading was 65% of incident radiation out of the wood in 2003, and 35% in 2004 after harvesting of some Eucalyptus trees. Under shade, tiller population leaf area and forage mass index were higher in the second year than in the first. Forage neutral detergent fiber value was higher at full sunlight than in the shade, while the crude protein content and in vitro dry matter digestibility were higher under the trees. Moderate shading increases crude protein and reduces neutral detergent fiber, therefore improving forage digestibility of grasses growing under trees

Características do pasto e desempenho de novilhas em sistema silvipastoril e pastagem de braquiária em monocultivo

The objective of this work was to evaluate the pasture characteristics and the performance of heifers from the Holstein x Zebu cross in a silvopastoral system (SPS), and in a Brachiaria (Urochloa decumbens) pasture. The experiment was set up in a randomized block design with two treatments: an exclusive Brachiaria pasture; and SPS, which had mixed U. decumbens and Stylosanthes guianensis strips alternating with strips with trees. Paddocks were grazed in rotational stocking, with seven days of grazing and 35 and 49 days of rest in the rainy and dry seasons, respectively. Pasture traits, dry matter intake and live weight gain did not vary with the systems. However, due to the reduction in the amount and nutritional value of the forage, these variables had higher values for the rainy season than the dry season, respectively: pre-grazing forage mass, 1,525 and 964 kg ha-1; crude protein, 9.3 and 8.2%; in vitro dry matter digestibility, 56.1 and 50.3%; dry matter intake, 2.3 and 1.6% of body weight; and live weight gain, 625 and 242 g per day per heifer. Moderate shading in SPS did not affect pasture traits, dry matter intake, or the performance of the heifers, in comparison to the values obtained for an exclusive Brachiaria pasture.O objetivo deste trabalho foi avaliar as características do pasto e o desempenho de novilhas oriundas do cruzamento Holandês x Zebu, em sistema silvipastoril (SSP) e em monocultivo de braquiária (Urochloa decumbens). O delineamento experimental foi o de blocos ao acaso, com dois tratamentos: em monocultivo de braquiária; e o SSP, que apresentava faixas de braquiária consorciada com Stylosanthes guianensis, alternadas com faixas arborizadas. Os piquetes foram manejados sob lotação rotacionada, com 7 dias de ocupação e 35 e 49 dias de descanso, nas épocas chuvosa e seca, respectivamente. As características do pasto, o consumo e o ganho de peso não variaram com o sistema; porém, devido às reduções na quantidade e no valor nutritivo da forragem, apresentaram valores maiores na época chuvosa do que na época seca, respectivamente: massa de forragem pré-pastejo, 1.525 e 964 kg ha-1; teores de proteína bruta na gramínea, 9,3 e 8,2%; digestibilidade in vitro da matéria seca, 56,1 e 50,3%; consumo de matéria seca, 2,3 e 1,6% do peso vivo; ganho de peso de 625 e 242 g por dia por novilha. O sombreamento moderado no SSP não interferiu nas características do pasto, nem no consumo de forragem, nem no desempenho de novilhas leiteiras, quando comparado aos valores obtidos na pastagem de braquiária em monocultivo

Flemingia macrophylla in goat feeding

ABSTRACT -The objective of this work was to evaluate the inclusion of Fabaceae Flemingia macrophylla (Willd.) Kuntze ex Merr. in the diet of lactating dairy goats arranged in a 5 × 5 Latin square. The diets were composed of 40% of concentrate and 60% of roughage, and the dietary treatments were defined by the level of Flemingia hay inclusion (0%, 8%, 16%, 24%, and 32% in the diet dry matter) replacing Cynodon dactylon cv. Tifton 85 hay. The diets were isonitrogenous, with 14% crude protein. Feed intake, nutrient digestibility, feeding behavior, and ruminal pH and ammonia nitrogen were evaluated. There was no difference in dry matter intake with the inclusion of Flemingia hay in the diet. The digestibility of dry matter, organic matter, crude protein, neutral detergent fiber, and total carbohydrates decreased with the inclusion of Flemingia in the diet. The diet did not change rumen ammonia nitrogen concentration or ruminal pH. There were no differences in the feeding behavior or feed and rumination efficiencies. Flemingia macrophylla can be used up to the level of 32% in the dry matter in diets for lactating goats

Grãos de leguminosas moídas como fonte de urease para amonização do feno de capim-elefante

The objective of this work was to evaluate the use of soybean (Glycine max), pigeon pea (Cajanus cajan), and jack bean (Canavalia ensiformis) as urease sources for elephant grass (Pennisetum purpureum) hay ammoniated with urea. The experimental design was completely randomized in a double factorial arrangement with one additional treatment: 4 urease source levels x 3 urease sources + 1 control. Chemical-bromatological analyses and carbohydrate fractionation were performed in the hay, and cumulative gas production in vitro was determined. There were interactions between urease level and source for neutral detergent fiber and acid detergent fiber, in which 1 and 2% jack bean lowered acid detergent fiber values, and 2% jack bean and 3% soybean reduced lignin content. The addition of milled legume grains reduces fiber components and increases non protein nitrogen content in elephant grass hay ammoniated with urea. Adding 4% milled soybean increases gas production in the soluble fraction.O objetivo deste trabalho foi avaliar o efeito da inclusão de soja (Glycine max), feijão-guandu (Cajanus cajan) e feijão-de-porco (Canavalia ensiformis) como fonte de urease para feno de capim-elefante (Pennisetum purpureum) amonizado com ureia. O delineamento experimental foi inteiramente casualizado, em arranjo fatorial duplo, com um tratamento adicional: 4 níveis de fonte de urease x 3 fontes de urease + 1 controle. Realizou-se a análise química-bromatológica e o fracionamento de carboidratos no feno, e a produção cumulativa de gás in vitro foi determinada. Houve efeito da interação entre o nível e a fonte de urease para fibra em detergente neutro e fibra em detergente ácido, em que a adição de 1 e 2% de feijão-de-porco resultou nos menores valores de fibra em detergente ácido, e a adição de 2% de feijão-de-porco e 3% de soja, nos menores valores de lignina. A adição de grãos moídos das leguminosas reduz os componentes da fibra e aumenta o teor de nitrogênio não proteico do feno de capim-elefante amonizado com ureia. A adição de 4% de grão de soja moído aumenta a produção de gás proveniente da fração solúvel

Subprodutos agroindustriais na ensilagem de Pennisetum purpureum/ Agroindustrial by-products in Pennisetum purpureum silage

Objetivou-se avaliar o efeito da inclusão de níveis crescentes (0, 5, 10, 15 e 20%) de polpa cítrica peletizada (PCP) e melaço em pó (MP) na ensilagem de capim-elefante. O delineamento experimental foi inteiramente casualizado, com 10 tratamentos e cinco repetições. Determinou-se o conteúdo de matéria seca (MS), teores de proteína bruta (PB), fibra em detergente neutro (FDN) e ácido (FDA), lignina (LIG), proteína insolúvel em detergente ácido (PIDA), carboidratos solúveis (CS), potencial hidrogeniônico (pH), nitrogênio amoniacal (N-NH3), perdas por efluentes (PE), perdas por gases (PG) e recuperação da matéria seca (RMS). Foram observados efeitos dos níveis de inclusão da PC e do MP sobre a massa de forragem ensilada. A PCP promoveu aumento de MS e CS, diminuição de FDN, FDA e LIG, e efeito quadrático para a PB. Observou-se redução na PE e PG, resultando em maior RMS com a inclusão deste aditivo. O MP aumentou o teor de MS e diminuiu a FDN, FDA e LIG linearmente. Entretanto, este aditivo promoveu aumento na PE e menor RMS. A PC proporcionou efeitos positivos sobre a silagem e sua inclusão até 10% melhora a qualidade nutricional e evita a redução do teor proteico do material. Por outro lado, o MP apresentou efeitos negativos sobre o teor proteico, perda por EFLU e produção de N.NH3, porém aumentou os teores de MS e CS, bem como as perdas via gás