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Showing papers in "Revista Brasileira De Zootecnia in 2009"


Journal ArticleDOI
TL;DR: Crop-livestock integrated systems (CLIS) have been widely used in tropical agriculture, such as in Brazil as mentioned in this paper, where minimum tillage has increased to more than 60% of soil tillage usage in Brazil.
Abstract: Sustainability is an actual theme and very present in all discussion in the tropical agriculture world, including Brazil. This country experienced high taxes of development in agribusiness, increasing exportation trading, producing foods of better quality and raising incoming rates of farmers. However, two mains aspects call the attention in respect to sustainability: excessive soil preparation with monoculture of annual crops and pasture degradation. These situations have brought losses in crop and livestock yields, increased soil degradation and collapse of natural resources. Continuous cropping of monoculture accelerates attacks of insects and diseases, specially the ones related to soil interactions. Technologies such as minimum tillage, crop rotation and crop-livestock integration can alleviate these problems and drive agriculture to sustainability. Minimum tillage has increase to more than 60% of soil tillage usage in Brazil. Adoption of this system in large scale, covering more regions, with different clime and soil, is highly dependent of crops that produce high amounts of residues and straw for better soil coverage. Crop-livestock integrated systems (CLIS) have been cultivated with many crops, such as: soybeans, corn, pearl millet, sorghum, cotton, sunflower, etc. and especially perennial tropical grasses asBrachiaria spp, intercropped or not. CLIS can be one important alternative to pasture recuperation and improvement of annual crops. They increase straw to minimum tillage systems, improve soil chemical, physical and biological properties, and better use of equipments, farmers income, and jobs in rural area. This paper analyze the state of the art in CLIS research, later results, and bring some considerations for the near the future of CLIS in Brazil.

242 citations


Journal ArticleDOI
TL;DR: Objetivou-se avaliar os efeitos de compostos nitrogenados suplementares sobre o consumo, a digestibilidade e a sintese de proteina microbiana em bovinos alimentados com forragem tropical de baixa qualidade sobre os consumos de MS, materia orgânica (MO) e fibra em detergente neutro (FDN).
Abstract: The objective of this study was to evaluate the effects of supplementation with nitrogenous compounds on intake, digestibility, and rumen microbial synthesis in cattle fed low-quality tropical forage. Five crossbred heifers, averaging 209 kg and fitted with ruminal fistulla, were used. The animals were fed ad libitum with signal grass (Brachiaria decumbens Stapf.) hay, which had crude protein (CP) content of 5.08%, as dry matter (DM) basis. The five treatments were defined according to the increasing level of CP in the diet (0, 3, 5, 7, and 9 percentile points above the forage CP level). The supplement consisted of the following nitrogen sources: urea, ammonium sulfate and albumin (4.5:0.5:1.0, respectively). The experiment was carried out according to a 5 × 5 Latin square design, with five experimental periods. The average CP levels in the diets were: 5.28, 8.08, 9.82, 11.87, and 13.63% on DM basis. The intakes of DM, organic matter (OM), and neutral detergent fiber (NDF) showed a quadratic response according to CP levels in the diet, with maximum responses at 10.83%, 10.78%, and 10.37% CP, respectively. The digestibility coefficients of OM and NDF showed a linear-response-plateau response according to CP levels, with the plateau beginning (maximum response) at 7.93% and 7.55% CP, respectively. The average daily concentration of rumen ammonia nitrogen (RAN) was positively related with CP levels. The RAN estimate associated with the maximum DM intake was 15.33 mg/dL. It was observed that intestinal flow of microbial nitrogenous compounds and nitrogen intake became equivalent to each other at 7.13% of CP.

180 citations


Journal ArticleDOI
TL;DR: As especies forrageiras mais produtivas e com maior potencial para utilizacao em ambiente silvipastoril foram: Axonopus catharinensis e Brachiaria brizantha cv.
Abstract: Objetivou-se avaliar o comportamento de especies forrageiras (Brachiaria decumbens cv. Basilisk, Brachiaria brizantha cv. Marandu, Panicum maximum cvs. Tanzânia, Aruana e Mombaca, Hemarthria altissima cv. Florida; Paspalum notatum cv. Pensacola, Axonopus catharinensis, Cynodon sp. hibrido Tifton-85; Arachis pintoi cvs. Alqueire e Amarillo) submetidas a diferentes niveis de luminosidade produzidos por arvores de Pinus taeda (ceu aberto; 9 m entre linhas e 3 m entre arvores; e 15 m entre linhas e 3 m entre arvores). Avaliaram-se a producao de MS, a relacao lâmina foliar:colmo (L:C), o nivel de florescimento das plantas, os teores de PB e FDN e as variaveis meteorologicas e do solo, na projecao da copa e no meio da entrelinha de arvores, de cada parcela. A producao de MS foi afetada negativamente pelo sombreamento, por outro lado, o teor de PB foi maior nas parcelas sombreadas em relacao ao pleno sol. Alem da menor radiacao, a velocidade do vento e a temperatura do solo nas parcelas sombreadas foram menores naquelas a sol pleno. O teor de FDN nao diferiu significativamente entre os niveis de luminosidade, embora a relacao L:C tenha sido maior na entrelinha do 9 × 3 em relacao aquela a ceu aberto. As especies forrageiras mais produtivas e com maior potencial para utilizacao em ambiente silvipastoril foram: Axonopus catharinensis e Brachiaria brizantha cv. Marandu.

107 citations


Journal ArticleDOI
TL;DR: The rumen flow of fibrous particles showed a linear-response-plateau pattern according to the CP levels in diets, and the degradation rate of potentially degradable NDF was linearly increased with the CP Levels in diets.
Abstract: The aim of this work was to evaluate the effects of supplementation with nitrogenous compounds on rumen dynamics of neutral detergent fiber (NDF) in cattle fed low-quality tropical forage. Five crossbred heifers with average live weight of 180 kg and fitted with rumen cannulae were used. The animals were fed ad libitum with signal grass (Brachiaria decumbens Stapf.) hay, which had crude protein (CP) content of 4.86% of dry matter (DM). The five treatments were proposed in order to raise the CP level of diets to 0, 2, 4, 6, and 8 percentile points above the CP level of the forage. The supplement was a mixture of urea, ammonium sulfate, and albumin (4.5:0.5:1.0, respectively). The experiment was carried out according to a 5 × 5 Latin square design, with five experimental periods. The average CP levels in the diets were: 5.19, 7.11, 8.60, 11.67, and 13.02% on DM basis. The potentially degradable NDF was linearly increased according to the CP levels in diet up to 6.97% of CP. From this point, there was stabilization of estimates (47.87% of NDF). The degradation rate of potentially degradable NDF was linearly increased with the CP levels in diets. The rumen flow of fibrous particles (L) showed a linear-response-plateau pattern according to the CP levels in diets. The plateau (maximum estimate) began on 7.24% of CP. The mean retention time in the rumen and the rumen fill effect of undegradable NDF were affect by the CP levels similarly to L, with plateau (minimum) beginning on 6.90 and 6.97% of CP, respectively.

107 citations


Journal ArticleDOI
TL;DR: The effect of four nitrogen doses and six water depths on elephant grass dry mass yield in the plant tops, crude protein (CP), neutral detergent fiber (NDF), and in vitro dry matter digestibility (IVDMD) during the dry and rainy periods was evaluated.
Abstract: The effect of four nitrogen (N) doses (100, 300, 500 e 700 kg/ha) and six water depths (0, 20, 40, 80, 100 and 120% of evapotranspiration) on elephant grass dry mass yield in the plant tops, crude protein (CP), neutral detergent fiber (NDF), and in vitro dry matter digestibility (IVDMD) during the dry and rainy periods was evaluated. The N doses were the plots and the water depths constituted the subplots, according to the complete randomized blocks experimental design with four replicates. The elephant grass dry mass yield in the plant tops accumulated either in the experimental year or during the rainy period, it increased linearly both in relation to the N doses and in relation to the water depths. During the dry period, the elephant grass production increased linearly with the N doses, but it had a quadratic behavior with the applied water depths. The CP content of the leaf blades plus pseudoculm of the elephant grass increased linearly with the N doses both in the experimental year as in the dry and rainy periods being, not influenced by the applied water depths. The NDF content in the leaf blades plus pseudoculm of the elephant grass plants was negatively influenced by the N doses during the experimental year and in the dry period, it was positively influenced by the supplement irrigation in the rainy period. The IVDMD of the leaf blades plus pseudoculm of the elephant grass was adjusted to the regression quadratic model according to the N doses only in the experimental year and in the rainy period; however, it was not influenced by the water depths. In the dry period, the IVDMD was not influenced by any of the studied variables.

95 citations


Journal ArticleDOI
TL;DR: The integration of precision feeding techniques into large-group production systems can provide real-time off-farm monitoring of feed and animals for optimal slaughter and production strategies, thus improving the environmental sustainability of pork production, animal well-being and meat-product quality.
Abstract: The high cost of feed ingredients, the use of non-renewable sources of phosphate and the dramatic increase in the environmental load resulting from the excessive land application of manure are major challenges for the livestock industry. Precision feeding is proposed as an essential approach to improve the utilization of dietary nitrogen, phosphorus and other nutrients and thus reduce feeding costs and nutrient excretion. Precision feeding requires accurate knowledge of the nutritional value of feedstuffs and animal nutrient requirements, the formulation of diets in accordance with environmental constraints, and the gradual adjustment of the dietary nutrient supply to match the requirements of the animals. After the nutritional potential of feed ingredients has been precisely determined and has been improved by the addition of enzymes (e.g. phytases) or feed treatments, the addition of environmental objectives to the traditional feed formulation algorithms can promote the sustainability of the swine industry by reducing nutrient excretion in swine operations with small increases in feeding costs. Increasing the number of feeding phases can also contribute to significant reductions in nutrient excretion and feeding costs. However, the use of precision feeding techniques in which pigs are fed individually with daily tailored diets can further improve the efficiency with which pigs utilize dietary nutrients. Precision feeding involves the use of feeding techniques that allow the provision of the right amount of feed with the right composition at the right time to each pig in the herd. Using this approach, it has been estimated that feeding costs can be reduced by more than 4.6%, and nitrogen and phosphorus excretion can both be reduced by more than 38%. Moreover, the integration of precision feeding techniques into large-group production systems can provide real-time off-farm monitoring of feed and animals for optimal slaughter and production strategies, thus improving the environmental sustainability of pork production, animal well-being and meat-product quality.

83 citations


Journal ArticleDOI
TL;DR: O trabalho foi realizado com o objetivo de avaliar a producao de B. decumbens cv.
Abstract: O trabalho foi realizado com o objetivo de avaliar a producao de B. decumbens cv. Basilisk e B. brizantha, cultivares Marandu e Xaraes, sob diferentes niveis de sombreamento. Utilizou-se delineamento em blocos casualizados com esquema de parcelas subdivididas, considerando os niveis de sombreamento (0, 50, 70%) como parcela e as especies ou cultivares como subparcelas. Sementes das gramineas foram postas a germinar em bandejas e transplantadas (tres plântulas por vaso). Foram realizados quatro cortes em cada subparcela. Antes de cada corte, mediram-se a altura de planta e a area foliar de quatro folhas em cada planta e quantificou-se o numero de perfilhos vivos por vaso. Apos a colheita, as plantas foram separadas em lâmina, colmo + bainha e material morto para determinacao da producao de materia seca. Para producao de materia seca total, calcularam-se a producao media em cada um os cortes e a producao total. No ultimo corte, avaliou-se a massa seca de raizes. As interacoes significativas foram desdobradas adequadamente. O fator qualitativo foi submetido a comparacao de medias pelo teste Tukey e o quantitativo a analise de regressao linear. A excecao da producao media em quatro cortes e da producao de colmos e de material morto, observou-se interacao significativa para todas as outras variaveis. Independentemente do nivel de sombreamento, o cultivar Xaraes destacou-se positivamente na maioria das caracteristicas analisadas, enquanto, no nivel de 50% de sombreamento, o capim-braquiaria apresentou maior produtividade, em porcentagem de producao a pleno sol. Na avaliacao da porcentagem de folhas, destacou-se o capim-xaraes, seguido do capim-marandu. Independentemente da forrageira, o nivel de sombreamento teve efeito direto sobre o numero de perfilhos/planta, a producao de MS do sistema radicular, a area foliar e o valor SPAD.

75 citations


Journal ArticleDOI
TL;DR: Benefits of supplementation of the diet of the grazing animals can increase the pasture carrying capacity and reduce the probability of future pasture degradation.
Abstract: O manejo do pastejo permite que sistema com base na utilizacao de pastagem propicie altos rendimentos por animal e por area. Para isto, devem-se utilizar criterios de manejo com intuito de controlar, simultaneamente a qualidade e a quantidade de forragem e manter a sustentabilidade do sistema. A intensidade de pastejo e dinâmica, jamais permanece a mesma, mudando com a taxa de consumo pelos animais e tambem pelo crescimento das plantas, variando de hora a hora e dia a dia, por isso deve ser controla sistematicamente. Neste cenario, o consumo de forragem parece ser o fator que mais explica as variacoes no desempenho animal em relacao a qualidade da forragem. A suplementacao da dieta dos animais em pastejo com concentrado permite aumentar o desempenho de animais, reduzindo a idade de abate ou a da primeira cria. Contudo, as caracteristicas nutricionais do suplemento devem variar em funcao da quantidade e da qualidade da forragem ofertada. Ao suplementar a dieta dos animais em pastejo com energia e proteina, pode-se manejar pastos mais baixos em relacao a suplementacao apenas com sal mineral, sem que ocorra reducao da densidade populacional de perfilhos. Estas estrategias de manejo podem reduzir a probabilidade de degradacao do pasto. Desta forma, a suplementacao da dieta de animais permite aumento na capacidade suporte do pasto.

73 citations


Journal ArticleDOI
TL;DR: The pasture deferred for the longest period showed the highest dead forage mass and falling index and the neutral detergent fiber was high and crude protein percentage diminished as the deferred period increased.
Abstract: This research was carried out aiming to assess the forage mass and its morphological components, pasture height and falling index, bulk density and the forage nutritional value on nitrogen (N) fertilized and deferred Brachiaria decumbens cv. Basilisk pastures. The treatments had 73, 95 and 116-day deferring periods, and 0, 40, 80 and 120 kg/ha N doses. A randomized block design with three replicates and subdivided plots was used. Total forage, green forage and green stem mass, as well as pasture height and forage bulk density increased along with the deferring periods and N doses. The pasture deferred for the longest period showed the highest dead forage mass and falling index. The neutral detergent fiber was high and crude protein (CP) percentage diminished as the deferred period increased. The CP percentage increased as the N dose increased. The deferring period and the nitrogen fertilization equally affected both deferred forage production and characteristics; however the deferred period has a higher magnitude. Performing nitrogen fertilization allows a reduction in the deferring period of pasture without reducing the forage production.

72 citations


Journal ArticleDOI
TL;DR: A carne de qualidade as discussed by the authors can be classified into four categories: suculencia (capacidade de retencao de agua), cor, textura (dureza ou maciez), odor and sabor.
Abstract: Considerando que a tendencia mundial e produzir o que se consome e que a ciencia da carne busca o mais alto grau de satisfacao do consumidor, o estudo aborda as caracteristicas que propiciam essa satisfacao na carne ovina. A utilizacao dos orgaos dos sentidos humanos na percepcao das caracteristicas que propiciam a mais alta satisfacao do consumidor, passou a ser definicao de "qualidade"; que aponta como caracteristicas sensoriais importantes da carne ovina a suculencia (capacidade de retencao de agua), cor, textura (dureza ou maciez), odor e sabor e o flavor (odor + sabor). Estas caracteristicas variam de acordo com a especie, raca, idade, sexo, alimentacao, manejo pos-mortem e as condicoes e tempo de conservacao do produto. Sendo que a maioria das investigacoes relacionam estas caracteristicas direta ou indiretamente com as do produto carnico cozido. O produtor, a industria e os segmentos da cadeia devem ter em conta que as propriedades sensoriais aceitaveis sao fundamentais no momento da venda e consumo. No agronegocio da carne, todos os segmentos da cadeia sao responsaveis e participam direta ou indiretamente na maxima satisfacao do consumidor, quer atraves dos atributos do produto ou pelo preco. Assim, o aperfeicoamento dos processos de producao, industrializacao e comercializacao para obter um produto de qualidade serao consolidados se existirem tecnicas claras e praticas para descrever os caracteres relacionados com a qualidade da carne, que possam ser medidos na carcaca e que tenham relacao biologica com uma avaliacao in vivo. A carne de qualidade e a que provoca o mais alto grau de satisfacao do consumidor e as caracteristicas sensoriais estao relacionadas a porcao comestivel, principalmente a relacao musculo/gordura e composicao e valor biologico destes. Porem, nao basta somente estudar o alimento, e importante ter presente que a meta e o consumidor e, que nem sempre esta educado para melhor apreciar as caracteristicas sensoriais do produto. Para medir as propriedades sensoriais perceptiveis do alimento, ou seja, os atributos desse alimento que e possivel detectar e avaliar por meio dos sentidos humanos, esta a analise sensorial. Para que se possa alcancar a "mais alta satisfacao possivel do consumidor" nao somente devem-se buscar no alimento as caracteristicas desejadas; mas, tambem e necessario que o consumidor seja educado para melhor apreciar estas caracteristicas.

71 citations


Journal ArticleDOI
TL;DR: It may be concluded that when specific information on corn hybrids is not available, those with higher production of grains at maturity are selected due to their elevated correlation with DM production and digestible DM.
Abstract: Objetivou-se estabelecer correlacoes entre caracteristicas quantitativas e qualitativas e avaliar a influencia dessas caracteristicas sobre a producao e a qualidade do milho para silagem. Utilizaram-se dados do Programa de Avaliacao de Cultivares de Milho para Silagem IAC/APTA/ESALQ para calculo das correlacoes de Pearson entre as variaveis. A producao de materia seca (MS) digestivel foi afetada tanto pelas producoes de massa e de graos quanto pelas digestibilidades da planta e do colmo. A producao de materia seca digestivel apresentou os maiores coeficientes de correlacao com a producao de MS (0,85); com as producoes de graos na ensilagem (0,60) e na maturidade (0,68); com producao de materia verde (0,47); e com o indice de espigas (0,48). Os coeficientes de correlacao entre a producao de materia seca digestivel e a digestibilidade da planta inteira (0,44) e da fracao colmo (0,38) foram inferiores aos obtidos para a producao de materia seca. A digestibilidade da planta dependeu principalmente da digestibilidade do colmo (0,60) e dos parâmetros relacionados aos graos. Na ausencia de informacoes especificas sobre os cultivares de milho para silagem, pode-se optar por aqueles de maior producao de graos a maturidade, em razao da elevada correlacao dessa caracteristica com producao de materia seca e com producao de materia seca digestivel.

Journal ArticleDOI
TL;DR: Rest periods beyond the point where swards achieved 95% LI (100% LI or 28-d during the summer) resulted in higher accumulation and higher pre-graze FM, although this corresponded mainly to large amounts of stem and dead material, which could negatively affect the nutritive value of the forage produced and animal performance.
Abstract: Objetivou-se comparar a dinâmica do acumulo de forragem em pastos de capim-xaraes [Brachiaria brizantha (A. Rich.) Stapf. cv. Xaraes] submetidos a tres estrategias de desfolhacao intermitente, uma baseada no calendario (pastejo a cada 28 dias) e duas na interceptacao luminosa (IL), aos 95 ou 100% de interceptacao luminosa. A massa de forragem (MF) pre-pastejo foi maior na estrategia de desfolhacao aos 100% de interceptacao de luz. Os piquetes pastejados aos 95% de interceptacao de luz e a cada 28 dias apresentaram menores massas de forragem e nao diferiram entre si na primavera. O pastejo aos 95% de interceptacao de luz aumentou a proporcao de folhas, apesar das menores massas pre-pastejo. O pastejo aos 100% de interceptacao de luz resultou na menor porcentagem de folhas na massa de forragem, indicando que a maior producao total de forragem foi ocasionada pelo maior alongamento de colmos, o que esta associado a competicao por luz entre as plantas no interior do dossel. O prolongamento do periodo de descanso para alem dos 95% de interceptacao da luz incidente aumenta a massa de forragem na entrada dos animais no momento do pastejo (100% IL ou a cada 28 dias durante o verao), porem, esse aumento e resultado do acumulo de colmos e material morto e pode afetar negativamente o valor nutritivo da forragem produzida e o desempenho animal.

Journal ArticleDOI
TL;DR: A supplementation in the dry season in Brachiaria is biologically feasible for positive effect on weight gain, but the economic viability of the system is location dependent and supplementation levels above 0.8% of the BW should be investigated as alternatives that may avoid possible negative effects on the rumen environment.
Abstract: The objective was to evaluate the results of supplementation in the dry season of the year and the possible interference of the forage availability and quality and level of supplementation on performance. The total DM and green dry matter pasture availability deferred for use in the dry season has an average of all experiments of 6,431 kg ha-1 and 2,173 kg ha-1. The Brachiaria under grazing in the dry season have high levels of NDF, with an average of 74.50%, high levels of ADF, with an average of 44.19%, low levels of CP, with average of 5.59% and low levels of IVDM/O, with an average of 51.36%. In this sense, the diet taken by the animal usually presents higher crude protein and lower levels of NDF. On consumption in grazing, note that the intake reduction is limited by until the level of supplementation of 0.3% of body weight (BW) per day and when the consumption of supplement increases to levels above 0.3% of BW, the consumption of grass is low and that this decrease may be even greater when the supply of supplement is 0.8% of the BW. Supplementation of cattle provided larger gains than those receiving only mineral in the dry season. Must be guaranteed at least 4,500 kg DM total.ha-1, 1,200 kg.ha-1 of green dry matter, offering 10 to 12% of the BW offorage DM and 6% of DM potentially digestible to ensure selectivity and earnings satisfactory individual without compromising the gain per area. A supplementation in the dry season in Brachiaria is biologically feasible for positive effect on weight gain, but the economic viability of the system is location dependent. Supplementation levels above 0.8% of the BW should be investigated as alternatives that may avoid possible negative effects on the rumen environment to reduce the expectations of gain, as the fractionation of supplementation.

Journal ArticleDOI
TL;DR: The heritability estimates obtained in the multivariate analysis were high, especially at 3 and 5 years of age, suggesting better partition of genetic and environmental variances compared to uni and bivariate analyses but, high computer demands can still hinder its use in large databases.
Abstract: Dados de 19.458 animais da raca Nelore, nascidos entre 1975 e 2002 e pertencentes a oito fazendas participantes do Programa de Melhoramento Genetico da Raca Nelore (PMGRN), foram utilizados para estimar componentes de covariância, herdabilidade e correlacoes geneticas dos pesos ao nascimento, a desmama, ao sobreano e aos 2, 3 e 5 anos de idade. Utilizou-se o metodo da maxima verossimilhanca restrita, em analises uni, bi e multicaracteristicas, com modelos que incluiram o efeito genetico aditivo direto, como aleatorio, alem dos efeitos fixos de grupo de contemporâneos e os efeitos linear e quadratico da idade do animal a pesagem (com excecao do modelo para peso ao nascer) e da idade da mae ao parto. O efeito aleatorio de ambiente permanente materno tambem foi incluido nos modelos de analise do peso ao nascer, peso a desmama e peso ao sobreano e o efeito aleatorio genetico materno somente no modelo do peso a desmama. As herdabilidades estimadas em analise multicaracteristica para os pesos ao nascer, a desmama, ao sobreano, aos 2, 3 e aos 5 anos de idade foram 0,25; 0,33; 0,34; 0,32; 0,33 e 0,35, respectivamente. As correlacoes geneticas estimadas entre os pesos foram positivas e de moderadas a altas magnitudes e tenderam a diminuir com o aumento da distância entre as pesagens, o que indica que a selecao para peso em qualquer idade devera promover mudanca genetica nos pesos nas demais idades, inclusive no peso adulto de femeas da raca Nelore. As estimativas de herdabilidade obtidas na analise multicaracteristica foram superiores, sobretudo para os pesos aos 3 e aos 5 anos de idade, o que sugere melhor particao das variâncias genetica e de ambiente em comparacao as analises uni e bicaracteristicas, porem a alta demanda de recursos computacionais em analises de muitas caracteristicas pode ainda dificultar o uso dessas analises em grandes bancos de dados.

Journal ArticleDOI
TL;DR: The objective of this work was to evaluate the morphogenetic and structural characteristics of Brachiaria brizantha and decumbens submitted to different nitrogen doses, and found that the daily foliar structure emergence, total number of leaves and number of tillers per B. decumben plant was higher for B. brizintha, however, for phyllochron, thedaily foliar prolongation and life duration of the B. Brizantha leaf were higher.
Abstract: The objective of this work was to evaluate the morphogenetic and structural characteristics of Brachiaria brizantha and decumbens submitted to different nitrogen doses (N). The experiment was carried in a greenhouse. The treatments consisted of four N doses (0, 75, 150 and 225 mg/dm3 of N) and two grasses (Brachiaria brizantha and decumbens). Nitrogen fertilization was subdivided into three applications. A completely randomized block experimental design with five repetitions was used. For the morphogenetic and structural characteristics, the daily foliar structure emergence, total number of leaves and number of tillers per B. decumbens plant was higher for B. brizantha. However, for phyllochron, the daily foliar prolongation and life duration of the B. brizantha leaf were higher. B. decumbens and brizantha responded increasingly up to 190 mg/dm3 of nitrogen in relation to the majority the available characteristics. The process senescence is accelerated with increase of the nitrogen doses, reducing the life duration of leaves.

Journal ArticleDOI
TL;DR: Signalgrass and forage peanut have great potential for evaluation and use in silvopastoral systems where the light transmission level is around 50% of photosynthetically active radiation.
Abstract: The morphological and structural characteristics and dry matter production of signalgrass (Brachiaria decumbens, cv. Basilisk) and forage peanut (Arachis pintoi, cv. Amarillo) were evaluated in response to different shading levels (0, 50 and 70%). A randomized complete block design was used with four replications. Three and two harvests for signalgrass and forage peanut were made, respectively. Forage peanut showed significant reduction in dry matter production with shading, only in the second harvest. Dry matter production of signalgrass decreased linearly in the first and second harvest. In all the harvests evaluated, average sward height, petiole length, and stem and leaf blade length increased significantly with shading. Increasing shade levels promoted linear reduction in the tiller population density of signalgrass, in the three harvests evaluated. On the other hand, mean tiller weight was only affected in the third harvest, showing a linear increment with increasing shade levels. The leaf:stem ratio of signalgrass and forage peanut was not significantly altered by shade. Specific leaf area, leaf area per leaflet and leaf area per tiller increased with shading. Leaf area index (LAI) showed linear reduction with shading in the second harvest of forage peanut and signalgrass. Signalgrass and forage peanut have great potential for evaluation and use in silvopastoral systems where the light transmission level is around 50% of photosynthetically active radiation.

Journal ArticleDOI
TL;DR: Post-grazing residues of Tanzania guineagrass under rotational stocking management may be set at either 25 or 50 cm, since the herbage intake was not affected within this grazing intensity range, however, herbage removal and grazing efficiency were reduced with the 50 cm post-Grazing height and grazing time increased with long occupation periods.
Abstract: The objective of this experiment was to evaluate the ingestive behaviour, herbage intake and grazing efficiency of beef cattle steers grazing on Panicum maximum Jacq. cv. Tanzania subjected to different rotational stocking intensities. Treatments corresponded to two post-grazing conditions (residues of 25 and 50 cm) associated with a pre-grazing condition of 95% sward canopy light interception during regrowth (LI). The grazing time increased linearly with the duration of the occupation period (475 to 630 minutes/day). On paddocks grazed down to a residue of 25 cm, the bite rate increased linearly along the occupation period, with an average of 42.5 bites/minute. On paddocks grazed down to a residue of 50 cm, the bite rate was stable and equal to 39 bites/minute. There was no difference in herbage intake between grazing intensities. However, grazing at 25 cm residue resulted in greater herbage removal (68.0 vs. 45.6%) and greater grazing efficiency (90.4 vs. 49.8%) than grazing at 50 cm residue. Post-grazing residues of Tanzania guineagrass under rotational stocking management may be set at either 25 or 50 cm, since the herbage intake was not affected within this grazing intensity range. However, herbage removal and grazing efficiency were reduced with the 50 cm post-grazing height and grazing time increased with long occupation periods.

Journal ArticleDOI
TL;DR: In the semi-arid region of Brazil, a large number of cattle farms are located in rural areas and the major occupation is agriculture and livestock production as discussed by the authors, which is one of the few options in these areas, mainly in northeast Brazil, where the feeding systems are based on cultivated forage crops and use of native vegetation.
Abstract: The Brazilian semi-arid region has 928 km2 ranging from the northern portion of Minas Gerais and Espirito Santo States, the semi-arid lands of Bahia, Sergipe, Alagoas, Pernambuco, Paraiba, Rio Grande do Norte, Ceara, and Piaui States, and 45 counties from southeastern Maranhao State. Population is mainly concentrated in rural areas and the major occupation is agriculture and livestock production. Dairy production is one of the few options in these areas, mainly in northeast Brazil, where the feeding systems are based on cultivated forage crops and use of native vegetation, predominately the "Caatinga". These aspects give seasonal characteristics for the production on this region. Inadequate amount and distribution of rainfall in this region presenting strong spatial and seasonal variability and prolonged dry periods practically determines the need for supplementation feeding for dairy cows for production systems located in the semi-arid region. Thus, supplementation has been based on the use of forage resources adapted to the drought, by-products, residues from local agro-industry, and on concentrate feeding. Farmers are also using different options trying to reduce costs without losing productivity during the dry periods. Production systems such as "CBL" (Caatinga-Buffel Grass-Leucaena) and "Gloria System" have been proposed aiming to alleviate the adversities. In addition to these systems, the utilization of agro industrial by-products, crop residues, and native forage resources are important options. In this aspect, the forage cactus (Opuntia ficus-indica Mill.) deserves special attention for its great adaptation, nutritive value, and productivity in the region.

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TL;DR: Genotype and diet influenced significantly the saturated fatty acids (SFA) concentration, with ½Dorper + ½Santa Inez crossbred obtaining the lowest mean, behavior similar to that observed for PUFA concentrations.
Abstract: To assess the influence of genotype and diets with different energy levels on the lipid profile of sheep meat, 54 lambs were used (18 animals from each genotype: Morada Nova, Santa Inez and ½Dorper + ½Santa Inez crossbred), distributed in a completely randomized experimental design in a 3 × 2 factorial arragement (three genotypes and two diets). The animals were submitted to two diets, 2.5 Mcal ME/kg DM and 3.0 Mcal ME/kg DM, receiving feed and water to reach the desired average live weight of 30 kg, when they were slaughtered. Total lipids, cholesterol, phospholipids and fatty acids profile of the Longissimus muscle were assessed. Diet and genotype did not influence the total lipids, cholesterol and phospholipids contents. The diet with the highest energy value presented higher values for the concentration of C12:0, C14:0, C18:0, C19:0, C22:0 acids and monounsaturated fatty acids (MUFA) in relation to that with the lowest energy value. However, for the concentrations of C15:0 acid and polyunsaturated fatty acids (PUFA), the highest values were recorded for diet with the lowest energy value. Genotype and diet influenced significantly the MUFA concentration, in which ½Dorper + ½Santa Inez crossbred genotype and diet with 2.5 Mcal ME/kg DM showed the highest values. Genotype influenced the saturated fatty acids (SFA) concentration, with ½Dorper + ½Santa Inez crossbred obtaining the lowest mean, behavior similar to that observed for PUFA concentrations. Desirable fatty acids (DFA), atherogenicity index as well as PUFA:SFA, MUFA:SFA, (C18:0 + C18:1):C16:0 ratios were influenced by diet and genotype. ½Dorper + ½Santa Inez crossbred and diet with 2.5 Mcal ME/kg DM obtained the best results.

Journal ArticleDOI
TL;DR: A profundidade do bocado foi obtida em 40 perfilhos marcados por unidade experimental, em medicoes realizadas antes e apos o pastejo, e Observou-se correlacao positiva entre a altura do pasto e a massa de forragem, e negativa com a densidade of forragam.
Abstract: Com o objetivo de avaliar o efeito da estrutura de uma pastagem nativa nos parâmetros que compoem o processo de ingestao de forragem de ovelhas e bezerras em pastejo, foram estabelecidas quatro alturas de pasto (4, 8, 12 e 16 cm), em delineamento estatistico inteiramente casualizado, com quatro tratamentos e duas repeticoes no tempo e no espaco. A massa do bocado e a taxa de ingestao foram estimados por diferenca de peso vivo corrigido para a perda de peso metabolico, durante 45 minutos. Os movimentos mandibulares de apreensao e mastigacao foram registrados pelo aparelho IGER Behaviour Recorder. A profundidade do bocado foi obtida em 40 perfilhos marcados por unidade experimental, em medicoes realizadas antes e apos o pastejo. Observou-se correlacao positiva entre a altura do pasto e a massa de forragem, e negativa com a densidade de forragem. A profundidade de bocados apresentou relacao linear e positiva com o aumento da altura do pasto e nao diferiu entre especies animais. Acima de 9,5 cm de altura do pasto, a profundidade do bocado das ovelhas nao compensou a pouca densidade de forragem nos estratos mais superiores, o que reduziu a massa do bocado. A mesma resposta foi observada a partir da altura do pasto de 11,4 cm para as bezerras. Com o aumento da massa do bocado, houve diminuicao na taxa de bocados e aumento na taxa de mastigacao. A taxa de ingestao foi maior nas alturas em que a massa de bocados foi tambem superior, o que evidencia a correlacao positiva entre as duas variaveis. Nessas condicoes, para aumentar o consumo de ovelhas e bezerras em campo nativo, a estrutura ideal de manejo requer manutencao de altura do pasto entre 9,5 e 11,4 cm, respectivamente.

Journal ArticleDOI
TL;DR: The nutrient digestibility estimates by iNDF was overestimated and those estimated by iADF, chromium oxide, titanium dioxide and LIPE®, did not differ from the digestibility calculated on total fecal collection.
Abstract: Foram conduzidos dois experimentos com o objetivo de avaliar os indicadores internos fibra em detergente neutro indigestivel (FDNi) e fibra em detergente acido (FDAi), obtidos por incubacao in situ durante seis dias, e os indicadores externos oxido cromico (Cr2O3), dioxido de titânio (TiO2) e lignina isolada, purificada e enriquecida (LIPE®) em dois esquemas de coleta total de fezes (3 ou 5 dias) para estimativa da digestibilidade em bovinos. O delineamento experimental foi o de blocos ao acaso com parcelas subdivididas. No primeiro experimento, foram utilizadas cinco novilhas mesticas alimentadas com cana-de-acucar com 1% de ureia/sulfato de amonio e concentrado (1% do peso vivo). Nao houve diferencas entre as metodologias de coleta para a digestibilidade da materia seca. Quando estimada utilizando-se FDAi, a digestibilidade dos nutrientes foi subestimada, mas, quando estimada utilizando-se FDNi e os indicadores externos (oxido cromico, dioxido de titânio e LIPE®), nao diferiu significativamente daquela determinada por coleta total de fezes. No segundo experimento, foram utilizadas oito vacas em lactacao alimentadas com silagem de milho e 4 kg de concentrado. Nao houve diferenca na digestibilidade da materia seca entre os periodos de coleta. A digestibilidade dos nutrientes, quando estimada utilizando-se FDNi, foi superestimada, mas, quando estimada utilizando-se FDAi e os indicadores externos (oxido cromico, dioxido de titânio e LIPE®), nao diferiu significativamente daquela determinada por coleta total de fezes. Tres dias de coleta sao suficientes para estimativa da digestibilidade e os indicadores testados sao eficientes na determinacao da digestibilidade.

Journal ArticleDOI
TL;DR: Within PLP, precision grazing consists of the integration of information and communication technologies with knowledge about animal behavior and physiology to improve production of meat, milk and wool in grazing conditions to minimize overgrazing of sensitive areas and to maximize the quality of the product through enhanced traceability.
Abstract: Precision livestock production (PLP) is the augmentation of precision agriculture (PA) concepts to include all components of agroecosystems, particularly animals and plant-animal interactions. Soil, plants and soil-plant interactions are the subjects of PA or site-specific farming, where the main principle is to exploit natural spatial heterogeneity to increase efficiency and reduce environmental impacts. For the most part, PA has been studied and developed for intensive cropping systems with little attention devoted to pastoral and agropastoral systems. PLP focuses on the animal component and exploits heterogeneity in space and among individual animals towards more efficient and environmentally friendly production. Within PLP, precision grazing consists of the integration of information and communication technologies with knowledge about animal behavior and physiology to improve production of meat, milk and wool in grazing conditions. Two main goals are to minimize overgrazing of sensitive areas and to maximize the quality of the product through enhanced traceability. An integrated precision grazing system is outlined with its components: sensors of animal position, behavior and physiological status, real-time transmission of information to a decision support system, and feed-back through a series of actuators. Control of animal movement and diets is based on knowledge about species specific responses to various stimuli within the paradigms of flavor aversions and operant conditioning. Recent advances in the technologies and instrumentation available are reviewed briefly and linked to current livestock identification systems. The precision grazing vision is presented in full and the areas that need further research and development are discussed.

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TL;DR: In this paper, the authors evaluated the contents of in situ indigestible neutral detergent fiber (iNDF) and the fibrous particles lost in aqueous environment in some ruminant feeds by using bags made with different textiles.
Abstract: The aim of this work was to evaluate the contents of in situ indigestible neutral detergent fiber (iNDF) and the fibrous particles lost in aqueous environment in some ruminant feeds by using bags made with different textiles. The physical structure of the textiles was also observed. Wheat bran (WB), soybean hulls (SH), corn silage (CS), and signal grass hay (SGH) samples were used. The bags used for rumen incubation were made of nylon (50 µm); F57 (Ankom®); and non-woven textile (NWT -100 g/m²). The feed samples were ground (1 mm) and conditioned in bags (4 × 5 cm) (six bags of each feedstuff/textile), in a ratio of 20 mg of dry matter/cm2 of surface. The bags were incubated in the rumen of a cow fed with corn silage (70%) and concentrate (30%) for 144 hours. After that, the bags were removed, cleaned with running water and treated with neutral detergent. The residue was assumed as iNDF. The iNDF contents in WB, SH and CS were similar for F57 and NWT, but lower values were obtained when nylon was used For the SGH samples, all textiles produced different results, and the lowest contents were obtained with nylon. The fibrous particle losses in the aqueous environment were evaluated by cleaning the bags in warm running water (39oC) (10 bags/textile). The loss of fibrous particles was significant for nylon. This loss was considered the cause of lower iNDF contents obtained by using nylon textile, since the microscopic evaluation did not show the occurrence of ruptures during incubation or neutral detergent extraction.

Journal ArticleDOI
TL;DR: In this paper, the sward structure and nutritive value of Panicum maximum Jacq. cv. Tanzânia subjected to rotational stocking managements characterised by a common pre-grazing condition of 95% canopy light interception (LI) and two post grazing residues, 25 and 50 cm.
Abstract: The objective of this work was to evaluate the sward structure and nutritive value of Panicum maximum Jacq. cv. Tanzânia subjected to rotational stocking managements characterised by a common pre-grazing condition of 95% canopy light interception (LI) and two post-grazing residues, 25 and 50 cm. Treatments (95/25, 95/50 - LI/residue) were assigned to experimental units (groups of six 2500 m2 paddocks per treatment) according to a complete randomised block design, with two replications. The variables measured corresponded to: canopy light interception, pre and post-grazing sward height, herbage mass and pre and post-grazing morphological composition, herbage bulk density, herbage accumulation and nutritive value (including to IVOMD) of the morphological components. Pre-grazing herbage mass did not differ between residues, although the herbage accumulation rate was higher for the 50 than the 25 cm (164.9 and 90.6 kg/ha.day DM, respectively). Post-grazing herbage mass values were higher for the 50 cm residue and were characterised by a higher proportion of leaf blade in relation to the 25 cm treatment, which presented a higher proportion of dead material. On average, the contents of crude protein (CP), neutral detergent fibre (NDF) and lignin in acid detergent (LAD) as well as the values of the "in vitro" organic matter digestibility (IVOMD) were similar for both treatments. Crude protein and IVOMD decreased and NDF and LAD increased from top to the bottom of the sward, indicating grazing intensity as an important variable for promoting adjustments in the grazing efficiency and nutritive value of the consumed herbage by the grazing animals.

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TL;DR: A demografia de perfilhos, a composicao morfologica do pasto, o indice de area foliar (IAF), a taxa de acumulo de massa seca de forragem (TAcMS) and os teores de proteina bruta, fibra em detergente neutro e lignina and os coeficientes de digestibilidade in vitro da massaseca de Brachiaria decumbens cv.ano de N), em lotacao continua with
Abstract: Avaliaram-se a demografia de perfilhos, a composicao morfologica do pasto, o indice de area foliar (IAF), a taxa de acumulo de massa seca de forragem (TAcMS) e os teores de proteina bruta, fibra em detergente neutro e lignina e os coeficientes de digestibilidade in vitro da massa seca de Brachiaria decumbens cv. Basilisk submetido a adubacao nitrogenada (75, 150, 225 e 300 kg/ha.ano de N), em lotacao continua com taxa de lotacao variavel em dois anos agricolas consecutivos. O delineamento foi em blocos casualizados, com duas repeticoes. No primeiro ano, a demografia de perfilhos vivos nao foi alterada pelos meses de avaliacao, mas, no segundo ano, foi maior nos meses de marco e abril. A adubacao nitrogenada promoveu resposta linear positiva na demografia de perfilhos vivos, no indice de area foliar e na taxa de acumulo de massa seca. Maiores proporcoes de lâminas foliares foram constatadas em marco do primeiro ano e em dezembro e janeiro do segundo ano, entretanto, as proporcoes de colmos no pasto nao diferiram entre os meses de avaliacao nos dois anos. Tambem foram observadas respostas lineares positivas dos teores de PB as doses de nitrogenio aplicadas em todos os meses nos dois anos. Os teores de FDN e lignina do capim-braquiaria sao influenciados pelos meses de avaliacao e variam entre anos.

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TL;DR: Without the rendering industry, the accumulation of unprocessed animal by-products would impede the meat industries and pose a serious potential hazard to animal and human health.
Abstract: One third to one half of each animal produced for meat, milk, eggs, and fiber is not consumed by humans. These raw materials are subjected to rendering processes resulting in many useful products. Meat and bone meal, meat meal, poultry meal, hydrolyzed feather meal, blood meal, fish meal, and animal fats are the primary products resulting from the rendering process. The most important and valuable use for these animal by-products is as feed ingredients for livestock, poultry, aquaculture, and companion animals. There are volumes of scientific references validating the nutritional qualities of these products, and there are no scientific reasons for altering the practice of feeding rendered products to animals. Government agencies regulate the processing of food and feed, and the rendering industry is scrutinized often. In addition, industry programs include good manufacturing practices, HACCP, Codes of Practice, and third-party certification. The rendering industry clearly understands its role in the safe and nutritious production of animal feed ingredients and has done it very effectively for over 100 years. The availability of rendered products for animal feeds in the future depends on regulation and the market. Regulatory agencies will determine whether certain raw materials can be used for animal feed. The National Renderers Association (NRA) supports the use of science as the basis for regulation while aesthetics, product specifications, and quality differences should be left to the market place. Without the rendering industry, the accumulation of unprocessed animal by-products would impede the meat industries and pose a serious potential hazard to animal and human health.

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TL;DR: A venda da carne apresentou lucratividade maior that a venda de cordeiro vivo, com maior valor no sistema sem desmame terminado na pastagem, no que o maior custo total foi observado no confinamento e o menor, no sistsema de cordEiro terminado com a mae em pasto.
Abstract: Os objetivos neste trabalho foram analisar a viabilidade economica de sistemas de producao de cordeiros e identificar os componentes de maior influencia no custo de producao. O estudo foi realizado em duas etapas. Na etapa 1, realizou-se a comparacao de quatro sistemas de terminacao de cordeiros: 1) desmame aos 60 dias e terminacao em pasto; 2) cordeiro com mae em pasto; 3) cordeiro com mae em pasto e concentrado (1% PC/dia) em creep feeding; e 4) desmame aos 60 dias e confinamento. Na etapa 2, um modulo de 150 ovelhas em 9 ha de pasto cultivado nos sistemas em pastagem e 7 ha no confinamento foi proposto a partir do experimento para avaliacoes economicas, considerando a venda de cordeiro vivo terminado ou abate e venda de carne, alem da venda de matrizes. Foram realizados calculos de custo fixo (depreciacao), variavel (materiais, mao-de-obra, transporte, abate, juros, conservacao, despesas gerais) e total (fixo+variavel), lucratividade e rentabilidade, valor presente liquido, taxa interna de retorno e custo/beneficio. O maior custo total foi observado no confinamento e o menor, no sistema de cordeiro terminado com a mae em pasto. A margem liquida na venda de cordeiros foi negativa em todos os sistemas. A venda de carne apresentou margem liquida negativa apenas para terminacao em confinamento. A taxa interna de retorno para venda de carne foi: 1,4% no desmamado em pasto; 4,3% no de cordeiro com mae em pasto; 2,1% no creep feeding; e -2,3% no confinamento. Os componentes do custo operacional total com maior influencia sobre o custo de producao nos sistemas a pasto, em ordem decrescente, foram mao-de-obra e alimentacao; no confinamento, foram alimentacao e mao-de-obra. A venda da carne apresentou lucratividade maior que a venda de cordeiro vivo, com maior valor no sistema sem desmame terminado na pastagem.

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TL;DR: The use of inoculantes microbianos no Brasil vem aumentando nos ultimos anos, embora o numero de trabalhos ainda seja pequeno quando comparado aos observados no exterior, principalmente no que se refere ao desempenho de animais as discussed by the authors.
Abstract: O uso de inoculantes microbianos no Brasil vem aumentando nos ultimos anos, embora o numero de trabalhos ainda seja pequeno quando comparado aos observados no exterior, principalmente no que se refere ao desempenho de animais. Nos estudos com silagens de milho e sorgo os inoculantes avaliados foram compostos exclusivamente de bacterias homofermentativas, que tambem representaram a maioria das pesquisas em silagens de capins, enquanto que nas silagens de cana-de-acucar predominou o uso de bacterias heterofermentativas. Em geral, o uso de bacterias homofermentativas apresentou resultados favoraveis apenas para as silagens de milho e capins, traduzidos na maioria das vezes por menores teores de fibra e valor de pH, compensados pelo maior teor de PB. No caso das heterofermentativas foram encontrados bons resultados principalmente para as silagens de cana-de-acucar, com menor pH e teor de compostos fibrosos em face aos aumentos do teor de carboidratos soluveis, associado a maior recuperacao de MS e aumento de estabilidade aerobia. A associacao de bacterias hetero e homofermentativas proporcionou respostas satisfatorias e potencialmente interessantes embora os dados nacionais ainda sejam escassos. Investimentos adicionais na interface forragem:microrganismo podera permitir exploracao de novas perspectivas de aplicacao e consolidacao das recomendacoes desses aditivos.

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TL;DR: Meat from adult animals was darker than lamb meat, and cooking losses were higher in Triceps brachii compared to Longissimus lumborum and Semimembranosus.
Abstract: Eighteen ½ Ile de France ½ Polwarth sheep (6 no castrated lambs, 6 discarded ewes and 6 discarded wethers) were used to evaluate qualitative traits of meat from different categories of sheep for muscle cuts (shoulder, loin and leg). The animals were raised in grazing system with tifton-85 pastures and supplemented with concentrate. Lambs were slaughtered at 32 kg body weight, close to 5 months of age. Ewes and wethers were slaughtered with 55 kg and 60 months of age. There were no differences in pH45mim and pH24h values among different animal categories and muscles of carcass cuts. There was difference in meat luminosity between lambs and adult animals, considering all the evaluated muscles. The red level did not differ between adult categories, but it was higher than values observed in lambs. In conclusion, meat from adult animals was darker than lamb meat. Considering all animal categories, cooking losses were higher in Triceps brachii compared to Longissimus lumborum and Semimembranosus. Values of pH and water retention capacity were similar among animal categories.

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TL;DR: Visando selecionar clones de palma forrageira resistentes a cochonilha-do-carmim, realizou-se um experimento em casa de vegetacao no periodo de setembro de 2001 a janeiro of 2002, em delineamento inteiramente casualizado.
Abstract: Visando selecionar clones de palma forrageira resistentes a cochonilha-do-carmim, realizou-se um experimento em casa de vegetacao no periodo de setembro de 2001 a janeiro de 2002. A partir de infestacao artificial com a cochonilha, foram testados 20 clones de palma forrageira, em delineamento inteiramente casualizado, com quatro repeticoes. Foram observadas a fixacao de colonias sobre os cladodios e a porcentagem de cladodios infestados, por meio de uma escala de notas variando de 0 a 5. Os clones que apresentaram maior resistencia ao ataque da praga foram Miuda e Orelha de Elefante.