Feeding behavior of post-weaned crossbred steers supplemented in the dry season of the year.

The objective of this study was to evaluate the feeding behavior of grazing steers supplemented in the dry season of the year. Thirty-two castrated crossbred (½ Holstein-Zebu) steers with an average initial weight of 378 ± 7.54 kg, aged 14 months, were distributed into four treatment groups in a completely randomized design with eight replicates. The animals were managed in an area covered with a pasture of Brachiaria brizantha cv. Marandu, in a rotational grazing system. The supplement was formulated so that the animals in the different treatment groups would ingest the same amount of crude protein (CP) daily. Thus, the treatments consisted of increasing levels of supplementation, based on the animals' body weight (BW), as the protein content of the supplement was reduced. The following treatments (dry matter basis) were tested: T2, supplement at 0.2% BW, with 50% CP; T4, supplement at 0.4% BW, with 25% CP; T6, supplement at 0.6% BW, with 16.67% CP; and T8, supplement at 0.8% BW, with 12.5% CP. Forage dry matter intake decreased linearly (P < 0.05), characterizing a substitution effect. The increasing supplementation levels influenced the animals' feeding behavior, especially grazing time, total feeding time, number of grazing bouts, and number of bites per day, which showed a positive quadratic response (P < 0.05), and rumination time, number of rumination bouts, number of cuds ruminated per day, and number of chews per ruminated cud, which exhibited a negative quadratic behavior (P < 0.05). Dry matter and neutral detergent fiber (NDF) feed efficiencies and dry matter and NDF rumination efficiencies responded quadratically (P < 0.05). In conclusion, concentrate supplementation at up to 0.8% BW improves the feeding behavior of grazing steers in terms of the intake of concentrate supplement and forage as well as the feed and rumination efficiencies.

Rumen fermentation and metabolic profile of rams fed with diets amended cottonseed cake.

The aim of the study was to evaluate the addition of increasing cottonseed cake contents in the diet. The diets were composed of corn silage (500 g kg-1) and concentrate feed (500 g kg-1) on a dry matter (DM) basis. The treatments consisted of the substitution of 0, 140, 280, and 420 g kg-1 soybean meal to cottonseed cake in the DM of concentrate feed. Four rams of the Santa Inês breed, average age of 12 months and average weight of 27.77 ± 3.87 kg, were distributed in a Latin square design (4 × 4) in a split-split-plot design, with diets in the plots and as subplots were 5 days of collection and the collection times. The results were subjected to analysis of variance and regression at 5% probability. The soybean meal substitution contents by cottonseed cake in the concentrate increased linearly the pH (P = 0.019). Ruminal ammonia-nitrogen concentration decreased linearly by 0.0137 mg dL-1 at each 10 g/kg of substitution and the time after feeding promoted the same effect (P < 0.001) decreased linearly by 0.6204 mg dL-1 at each hour after feeding. There was an increased linearly of 0.0116 mmol mL-1 at the concentration of propionic (P = 0.008) and a reduction of 0.0062 mmol mL-1 at the concentration of butyric (P = 0.009) with cottonseed cake content; however, the substitution did not influence the others short-chain fatty acids. Replacement of soybean meal with cottonseed cake in the sheep feed did not significantly alter the blood parameters, promoting minor changes in the ruminal parameters mainly in the ruminal ammonia-nitrogen without affecting the animal's health.

Características morfogênicas do capim-Tanzânia consorciado com Estilosantes Campo Grande ou adubado com nitrogênio sob pastejo / Morphogenetic characteristics in Tanzania grass conhsorted with Stylosanthes Campo Grande or fertilized with nitrogen under grazing

Objetivou-se avaliar as características morfogênicas e estruturais do capim-Tanzânia (Panicum maximum cv. Tanzânia) consorciado com Estilosantes Campo Grande (Stylosanthes capitata e Stylosanthes macrocephala) ou adubado com nitrogênio. O pasto foi manejado sob lotação contínua e taxa de lotação variável. Foi utilizado delineamento experimental em blocos ao acaso com parcelas subdivididas, com três repetições. Os tratamentos foram: capim-Tanzânia + Estilosantes; capim-Tanzânia + 75 Kg N.ha.ano-1; capim-Tanzânia + 150 Kg N.ha.ano-1 e capim-Tanzânia + 225 Kg N.ha.ano-1. Foram utilizados ureia e nitrato de amônia como fonte de nitrogênio. As avaliações morfogênicas foram realizadas na primavera e no verão. Foram avaliados 15 perfilhos por piquete, duas vezes por semana, durante quatro semanas por estação em estudo. As características morfogênicas, exceto a taxa de alongamento foliar (TAlF), não foram influenciadas pela adubação nitrogenada ou consórcio com Estilosantes. Os maiores valores para esta variável foram observados na primavera, nas pastagens adubadas. Desta forma, conclui-se que a adubação nitrogenada influencia a taxa de alongamento foliar (TAlF) do capim-Tanzânia, e este quando é cultivado em consórcio com o Estilosantes Campo Grande apresenta características morfogênicas semelhantes quando adubado com nitrogênio, à excessão da taxa de alongamento foliar.(AU)

This study aimed to study morphogenic and structural characteristics of Tanzania grass (Panicum maximum cv. Tanzania) intercropped with Estilosantes Campo Grande (Stylosanthes capitata and Stylosanthes macrocephala) or fertilized with nitrogen. The pasture was managed under continuous stocking and variable stocking rate. Were used a randomized complete blocks with split plots and three replications. The treatments were: Tanzania grass + Stylosanthes; Tanzania grass + 75 Kg N.ha. year-1; Tanzania grass + 150Kg N.ha.year-1; Tanzania grass + 225 Kg N.ha.year-1. Were used urea and ammonium nitrate as nitrogen source. The morphogenetic evaluations were conducted in the spring and summer. Were evaluated 15 tillers per paddock, twice a week for four weeks per season in study. The morphogenic characteristics were not affected by nitrogen fertilization or consortium, except the leaf elongation rate (LER). The highest values for this variable were observed in the spring in the fertilized pastures. Therefore, it is concluded that nitrogen fertilization influences the leaf elongation rate (LER) of Tanzania grass, and this one when is intercropped with Stylosanthes Campo Grande show morphogenic characteristics similar when fertilized with nitrogen, except for rate leaf elongation.(AU)

Acúmulo e composição morfológica do pasto de capim-Tanzânia adubado com nitrogênio ou consorciado com estilosantes Campo Grande / Accumulation and forage morphological composition of Tanzania grass fertilized with nitrogen or intercropped with Campo Grande stylosanthes

Objetivou-se avaliar o acúmulo de massa de forragem e a composição morfológica do pasto de capim-Tanzânia adubado com nitrogênio ou consorciado com estilosantes Campo Grande. Utilizou-se um delineamento experimental em blocos ao acaso com parcelas subdivididas, com três repetições. Os tratamentos foram constituídos por: Tanzânia + Estilosantes; Tanzânia + 75 kg N ha-1; Tanzânia + 150 kg N ha-1; Tanzânia + 225 kg N ha-1. A maior porcentagem de lâmina foliar verde foi observada na primavera e nos pastos com 150 e 225 kg de N/ha. A porcentagem de colmo+bainha verde foi maior no verão e no outono, assim como, nos pastos adubados com N. A porcentagem de material morto foi mais elevada no outono e inverno. Com a aplicação de 225 kg de N/ha, os pastos apresentaram maior acúmulo diário de massa de forragem em relação aos outros tratamentos. A circunferência das touceiras foi semelhante entre os pastos consorciados e adubados com N. A quantidade de perfilhos vivos foi maior quando utilizou-se doses mais elevadas de nitrogênio. Os pastos consorciados com estilosantes ou adubados com 75 e 150 kg de nitrogênio apresentam respostas semelhantes para as características estruturais do pasto, e para o acúmulo de forragem.

The objective was to evaluate the accumulation of forage yield, composition and morphology of Tanzania grass pastures (Panicum maximum Jacq. cv. Tanzania-1) fertilized with nitrogen or intercropped with Campo Grande Stylosanthes. Were used a randomized blocks with split plots with three replications and having treatments as main plots: Stylosanthes + Tanzania; Tanzania + 75 kg N ha-1; Tanzania + 150 kg N ha-1; Tanzania + 225 kg N ha-1 and the subplots seasons. The highest percentage of green leaf blade were observed in spring and the pastures with 150 and 225 kg N/ha. The percentage of green stem + sheath were higher in summer and autumn, as well as in pastures fertilized with N. The percentage of dead material was higher in autumn and winter. With the application of 225 kg N/ha, pastures had higher daily accumulation of dry matter in relation to other treatments. The circumference of the stools was similar between the consortium and pastures fertilized with N. The number of live tillers was higher when we used higher doses of nitrogen. Pastures intercropped with stylosanthes or nitrogen fertilized (75 and 150 kg) presents better morphology and daily accumulation of forage.

Recria de novilhos em pastagem com e sem suplementação proteico/energética nas águas: consumo, digestibilidade dos nutrientes e desempenho / Recreates of steers on pastures with and without supplementation proteineous / energetics in the waters: intake, digestibility of nutrients and performance

Objetivou-se com esse estudo avaliar o fornecimento de suplemento proteico e suplemento mineral na fase de recria de novilhos mestiços ½ Holandês x Zebu mantidos em pastagem de Brachiaria brizantha cv. Marandu, no período das águas e suas implicações sobre o consumo, a digestibilidade dos nutrientes e o desempenho animal. Foram utilizados 22 novilhos com média de sete meses de idade e peso corporal médio inicial de 164,09±12,13 kg, distribuídos em delineamento inteiramente casualizado, com dois tipos de suplemento e onze repetições por tipo de suplementação. Os consumos de matéria seca (MS) total e dos nutrientes apresentaram maiores médias para os animais que receberam suplemento proteico/ energético. A utilização do suplemento proteico/energético melhorou a digestibilidade dos nutrientes da dieta, com exceção para a digestibilidade da fibra em detergente neutro corrigido para cinzas e proteína (FDNcp). Os animais que receberam suplemento proteico/energético apresentaram melhor desempenho quando comparado aos que receberam a suplementação mineral. O uso de suplemento proteico/energético no período das águas proporciona maior aporte de nutrientes, melhora a digestibilidade dos nutrientes e o desempenho de novilhos mestiços criados em pastagem de Brachiaria brizantha.(AU)

The objective of this study was to evaluate the supply of supplement of protein and supplement mineral in the rearing of crossbred steers Holstein x Zebu ½ maintained on Brachiaria brizantha. Marandu, in the rainy season and its implications on intake, nutrient digestibility and animal performance. Were used 22 steers averaging seven months of age and mean initial body weight of 164.09 ± 12.13 kg, distributed in a completely randomized design with two types of supplement and eleven repetitions per supplementation. The intake of dry matter (DM) total and of the nutrients had higher averages for animals receiving supplement of protein/energy. The use of supplement of protein/energy has improved digestibility of the nutrients of, except for the digestibility of neutral detergent fiber corrected for ash and protein (NDFap). The animals that received supplement of protein/energy presented better performance when compared to those receiving supplementation mineral. The use of supplement of protein/energy in the rainy season provides major input of nutrients, improves digestibility of nutrients and performance of crossbred steers reared in Brachiaria brizantha.(AU)

Impact of increasing levels of spineless-cactus meal on the ingestive behaviour of grazing steers / Impacto do aumento dos níveis de farelo de palma forrageira sobre o comportamento ingestivo de novilhos em pastejo

The objective of this study was to evaluate the effect of different levels of spineless-cactus meal substituting for maize in diets for supplemented steers grazing on Urochoa brizantha during the postweaning phase. The experiment was conducted on Princesa do Mateiro farm, located in Ribeirão do Largo-BA, Brazil. Forty crossbred steers with an average body weight of 261 ± 7.46 kg were distributed into four groups for evaluation of the following four levels of substitution of ground maize for spinelesscactus meal: 0.00, 30.00, 60.00, and 90.00%. The results were analysed statistically by variance and regression analyses at a 5% error probability. Increasing the amount of spineless-cactus meal in the diet had a quadratic effect on the grazing time and on the time spent on other activities. The diet had a quadratic effect on the number of grazing periods, the number of periods at the trough, and the total feeding and chewing times. In contrast, the number of periods spent on other activities and on rumination was not influenced by the level of spineless-cactus meal. The bite rate, number of bites per swallow, and number of bites per day increased linearly, whereas the swallowing time and number of cuds ruminated per day decreased as the level of spineless-cactus meal added to the diet wasincreased. The feed and rumination efficiencies of dry matter, neutral detergent fibre, crude protein, and non-fibre carbohydrates were not influenced by the level of substitution of spineless-cactus meal for ground maize. Spinelesscactus meal levels close to 60% probably provided greater fibre degradation, leading the animals tospend more time on social interactions with the group, use the feed better, and possibly have a better feed conversion.(AU)

Objetivou-se avaliar os efeitos de diferentes níveis de substituição do milho pelo farelo de palma forrageira na dieta de novilhos mestiços sob suplementação em pastagens de Urochoa brizantha na fase de recria. O experimento foi conduzido na fazenda Princesa do Mateiro, no município de Ribeirão do Largo, Bahia. Foram utilizados 40 novilhos mestiços com peso corporal médio de 261 ± 7,46 kg, distribuídos em quatro grupos, para avaliação de quatro níveis de substituição do milho moído pelo farelo de palma forrageira, 0,00; 30,00; 60,00; e 90,00%. Os resultados foram analisados estatisticamente por meio de análise de variância e de regressão, a 5% de probabilidade de erro. O aumento da quantidade de farelo de palma na dieta provocou efeito quadrático no tempo de pastejo e no tempo destinado a outras atividades. Houve efeito quadrático da dieta sobre o número de períodos de pastejo, o número de períodos de cocho e para os tempos totais de alimentação e mastigação, ao contrário dos números de períodos destinados a outras atividades e à ruminação não foram influenciados pelos níveis de farelo de palma. A taxa de bocados, o número de bocados por deglutição e o número de bocados por dia aumentaram de forma crescente, enquanto o tempo de deglutição e o número de bolos ruminados por dia decresceram com o aumento dos níveis de farelo palma forrageira dieta. As eficiências de alimentação e ruminação da matéria seca, fibra em detergente neutro, proteína bruta e carboidratos não-fibrosos não foram influenciadas pelos níveis de substituição do milho moído pelo farelo de palma. Níveis próximos a 60% de farelo de palma forrageira provavelmente promoveu maior degradação da fibra, proporcionando aos animais mais tempo para a interação social entre o grupo, ummelhor aproveitamento e possivelmente melhor conversão alimentar.(AU)

Recria de novilhos em pastagem com e sem suplementação proteico/energética nas águas: consumo, digestibilidade dos nutrientes e desempenho / Recreates of steers on pastures with and without supplementation proteineous / energetics in the waters: intake, digestibility of nutrients and performance

Objetivou-se com esse estudo avaliar o fornecimento de suplemento proteico e suplemento mineral na fase de recria de novilhos mestiços ½ Holandês x Zebu mantidos em pastagem de Brachiaria brizantha cv. Marandu, no período das águas e suas implicações sobre o consumo, a digestibilidade dos nutrientes e o desempenho animal. Foram utilizados 22 novilhos com média de sete meses de idade e peso corporal médio inicial de 164,09±12,13 kg, distribuídos em delineamento inteiramente casualizado, com dois tipos de suplemento e onze repetições por tipo de suplementação. Os consumos de matéria seca (MS) total e dos nutrientes apresentaram maiores médias para os animais que receberam suplemento proteico/ energético. A utilização do suplemento proteico/energético melhorou a digestibilidade dos nutrientes da dieta, com exceção para a digestibilidade da fibra em detergente neutro corrigido para cinzas e proteína (FDNcp). Os animais que receberam suplemento proteico/energético apresentaram melhor desempenho quando comparado aos que receberam a suplementação mineral. O uso de suplemento proteico/energético no período das águas proporciona maior aporte de nutrientes, melhora a digestibilidade dos nutrientes e o desempenho de novilhos mestiços criados em pastagem de Brachiaria brizantha.

The objective of this study was to evaluate the supply of supplement of protein and supplement mineral in the rearing of crossbred steers Holstein x Zebu ½ maintained on Brachiaria brizantha. Marandu, in the rainy season and its implications on intake, nutrient digestibility and animal performance. Were used 22 steers averaging seven months of age and mean initial body weight of 164.09 ± 12.13 kg, distributed in a completely randomized design with two types of supplement and eleven repetitions per supplementation. The intake of dry matter (DM) total and of the nutrients had higher averages for animals receiving supplement of protein/energy. The use of supplement of protein/energy has improved digestibility of the nutrients of, except for the digestibility of neutral detergent fiber corrected for ash and protein (NDFap). The animals that received supplement of protein/energy presented better performance when compared to those receiving supplementation mineral. The use of supplement of protein/energy in the rainy season provides major input of nutrients, improves digestibility of nutrients and performance of crossbred steers reared in Brachiaria brizantha.

Características morfogênicas do capim-Tanzânia consorciado com Estilosantes Campo Grande ou adubado com nitrogênio sob pastejo / Morphogenetic characteristics in Tanzania grass conhsorted with Stylosanthes Campo Grande or fertilized with nitrogen under grazing

Objetivou-se avaliar as características morfogênicas e estruturais do capim-Tanzânia (Panicum maximum cv. Tanzânia) consorciado com Estilosantes Campo Grande (Stylosanthes capitata e Stylosanthes macrocephala) ou adubado com nitrogênio. O pasto foi manejado sob lotação contínua e taxa de lotação variável. Foi utilizado delineamento experimental em blocos ao acaso com parcelas subdivididas, com três repetições. Os tratamentos foram: capim-Tanzânia + Estilosantes; capim-Tanzânia + 75 Kg N.ha.ano-1; capim-Tanzânia + 150 Kg N.ha.ano-1 e capim-Tanzânia + 225 Kg N.ha.ano-1. Foram utilizados ureia e nitrato de amônia como fonte de nitrogênio. As avaliações morfogênicas foram realizadas na primavera e no verão. Foram avaliados 15 perfilhos por piquete, duas vezes por semana, durante quatro semanas por estação em estudo. As características morfogênicas, exceto a taxa de alongamento foliar (TAlF), não foram influenciadas pela adubação nitrogenada ou consórcio com Estilosantes. Os maiores valores para esta variável foram observados na primavera, nas pastagens adubadas. Desta forma, conclui-se que a adubação nitrogenada influencia a taxa de alongamento foliar (TAlF) do capim-Tanzânia, e este quando é cultivado em consórcio com o Estilosantes Campo Grande apresenta características morfogênicas semelhantes quando adubado com nitrogênio, à excessão da taxa de alongamento foliar.

This study aimed to study morphogenic and structural characteristics of Tanzania grass (Panicum maximum cv. Tanzania) intercropped with Estilosantes Campo Grande (Stylosanthes capitata and Stylosanthes macrocephala) or fertilized with nitrogen. The pasture was managed under continuous stocking and variable stocking rate. Were used a randomized complete blocks with split plots and three replications. The treatments were: Tanzania grass + Stylosanthes; Tanzania grass + 75 Kg N.ha. year-1; Tanzania grass + 150Kg N.ha.year-1; Tanzania grass + 225 Kg N.ha.year-1. Were used urea and ammonium nitrate as nitrogen source. The morphogenetic evaluations were conducted in the spring and summer. Were evaluated 15 tillers per paddock, twice a week for four weeks per season in study. The morphogenic characteristics were not affected by nitrogen fertilization or consortium, except the leaf elongation rate (LER). The highest values for this variable were observed in the spring in the fertilized pastures. Therefore, it is concluded that nitrogen fertilization influences the leaf elongation rate (LER) of Tanzania grass, and this one when is intercropped with Stylosanthes Campo Grande show morphogenic characteristics similar when fertilized with nitrogen, except for rate leaf elongation.

Impact of increasing levels of spineless-cactus meal on the ingestive behaviour of grazing steers / Impacto do aumento dos níveis de farelo de palma forrageira sobre o comportamento ingestivo de novilhos em pastejo

The objective of this study was to evaluate the effect of different levels of spineless-cactus meal substituting for maize in diets for supplemented steers grazing on Urochoa brizantha during the postweaning phase. The experiment was conducted on Princesa do Mateiro farm, located in Ribeirão do Largo-BA, Brazil. Forty crossbred steers with an average body weight of 261 ± 7.46 kg were distributed into four groups for evaluation of the following four levels of substitution of ground maize for spinelesscactus meal: 0.00, 30.00, 60.00, and 90.00%. The results were analysed statistically by variance and regression analyses at a 5% error probability. Increasing the amount of spineless-cactus meal in the diet had a quadratic effect on the grazing time and on the time spent on other activities. The diet had a quadratic effect on the number of grazing periods, the number of periods at the trough, and the total feeding and chewing times. In contrast, the number of periods spent on other activities and on rumination was not influenced by the level of spineless-cactus meal. The bite rate, number of bites per swallow, and number of bites per day increased linearly, whereas the swallowing time and number of cuds ruminated per day decreased as the level of spineless-cactus meal added to the diet wasincreased. The feed and rumination efficiencies of dry matter, neutral detergent fibre, crude protein, and non-fibre carbohydrates were not influenced by the level of substitution of spineless-cactus meal for ground maize. Spinelesscactus meal levels close to 60% probably provided greater fibre degradation, leading the animals tospend more time on social interactions with the group, use the feed better, and possibly have a better feed conversion.

Objetivou-se avaliar os efeitos de diferentes níveis de substituição do milho pelo farelo de palma forrageira na dieta de novilhos mestiços sob suplementação em pastagens de Urochoa brizantha na fase de recria. O experimento foi conduzido na fazenda Princesa do Mateiro, no município de Ribeirão do Largo, Bahia. Foram utilizados 40 novilhos mestiços com peso corporal médio de 261 ± 7,46 kg, distribuídos em quatro grupos, para avaliação de quatro níveis de substituição do milho moído pelo farelo de palma forrageira, 0,00; 30,00; 60,00; e 90,00%. Os resultados foram analisados estatisticamente por meio de análise de variância e de regressão, a 5% de probabilidade de erro. O aumento da quantidade de farelo de palma na dieta provocou efeito quadrático no tempo de pastejo e no tempo destinado a outras atividades. Houve efeito quadrático da dieta sobre o número de períodos de pastejo, o número de períodos de cocho e para os tempos totais de alimentação e mastigação, ao contrário dos números de períodos destinados a outras atividades e à ruminação não foram influenciados pelos níveis de farelo de palma. A taxa de bocados, o número de bocados por deglutição e o número de bocados por dia aumentaram de forma crescente, enquanto o tempo de deglutição e o número de bolos ruminados por dia decresceram com o aumento dos níveis de farelo palma forrageira dieta. As eficiências de alimentação e ruminação da matéria seca, fibra em detergente neutro, proteína bruta e carboidratos não-fibrosos não foram influenciadas pelos níveis de substituição do milho moído pelo farelo de palma. Níveis próximos a 60% de farelo de palma forrageira provavelmente promoveu maior degradação da fibra, proporcionando aos animais mais tempo para a interação social entre o grupo, ummelhor aproveitamento e possivelmente melhor conversão alimentar.

Produção e composição morfológica do capim-tanzânia fertilizado com nitrogênio nas estações do ano / Production and morphological composition of tanzania grass fertilized with increasing doses of nitrogen in the seasons of the year

O objetivo do trabalho foi avaliar a produção e os componentes morfológicos do capim-Tanzânia (Panicum maximum cv. Tanzânia), adubado com nitrogênio nas estações dos anos, sob pastejo intermitente. Utilizou-se um delineamento em blocos ao acaso com parcelas subdivididas no tempo, com quatro repetições sendo os tratamentos: zero, 150, 300 e 450 kg de N ha-1 ano-1 e as estações do ano: outono, inverno e primavera de 2008 e verão de 2008/09. O maior acúmulo de matéria seca por corte foi obtido na maior dose de N e na primavera e verão. A adubação nitrogenada, especialmente quando em altas doses, proporciona as maiores porcentagens de lâmina foliar e colmo+bainha, porém com redução nas porcentagens de material morto. Independentemente da dose de N, maiores porcentagens de lâmina foliar e menores de material morto foram obtidas na primavera e verão. A maior porcentagem de colmo+bainha foi obtida principalmente no verão e outono. Elevadas doses de N associadas a intervalos menores de pastejo promovem uma maior produção do capim-Tanzânia sob lotação intermitente.

The objective was to evaluate the production and morphological components of Tanzania grass (Panicum maximum cv. Tanzania), fertilized with nitrogen at the times of the year, under intermittent grazing. Was used a randomized blocks with split plot with four replications and the treatments: zero, 150, 300 and 450 kg of N.ha-1.year-1 and seasons of the year: fall, winter and spring 2008 and summer of 2008/09. The largest accumulation of dry matter per cutting was obtained at higher N and in spring and summer. The fertilizer N, especially at high doses, provides the highest percentage of leaf and stem + sheath, but with reduction in the percentage of dead material. Regardless of N, higher percentages of leaf and smaller dead material were obtained in spring and summer. The highest percentage of stem + sheath was obtained mainly in summer and autumn. High doses of N associated with shorter intervals grazing encourage greater production of Tanzania grass under intermittent stocking.

Metabolic activity interferometer: description and calibration of an interferometric method to measure growth of mycobacteria.

An interferometer that measures the refractive index changes due to bacterial metabolism is described. The apparatus permits simultaneous and real time measurement of bacterial growth in several samples of slowly growing mycobacteria. The error sources are discussed and the sensitivity of the apparatus is tested. For the species Mycobacterium bovis BCG and M. smegmatis, a relation between refractive index change and bacterial concentration is determined experimentally and the time constant of bacterial growth is measured.

Social isolation and expression of serotonergic neurotransmission-related genes in several brain areas of male mice.

Early-life events influence brain development and evoke long-lasting behavioral consequences. Postweaning social isolation in rodents induces emotional and neurochemical alterations similar to those observed among some human psychopathologies. Central serotonergic neurotransmission is intimately involved in the observed adjustments, but the impact of social deprivation on serotonergic gene expression is unknown. We investigated the effects of prolonged early social isolation on emotion-related behaviors and 5-hydroxytryptamine (5-HT)-related gene transcription in mice. After weaning, male C57BL/6J mice were reared singly or in groups of four for 6 weeks. Gene expression of 5-HT(1A), 5-HT(1B), 5-HT(2A), 5-HT(2C), 5-HT(3A), 5-HT(6) and 5-HT(7) receptors and of 5-HT transporter and tryptophan hydroxylase-2 was determined by quantitative real-time polymerase chain reaction in distinct brain areas. Single-housed mice were hyperactive in a novel environment and showed signs of aggressive behavior. Housing condition did not alter weight gain or body temperature. Isolation markedly reduced transcription of all postsynaptic 5-HT receptors in the prefrontal cortex and reduced 5-HT(1B), 5-HT(2A) and 5-HT(2C) in both hypothalamus and midbrain. In contrast, the only alteration in the hippocampus was 5-HT(6) overexpression. Neither 5-HT transporter nor synthetic enzyme gene transcription differed between housing conditions. In conclusion, early social isolation in mice induces robust changes in postsynaptic 5-HT receptors gene transcription, motor hyperactivity and behavioral disinhibition. The overall pattern of decreased gene expression in the prefrontal cortex highlights its high vulnerability to environment. Furthermore, this is the first study to present a general representation of 5-HT-related gene expression in specific brain areas after social isolation and identifies novel candidates that may be critical for underlying molecular mechanisms.

Observing bacterial activity interferometrically.

It is shown that bacterial activity, even of slowly growing species, can be detected by precise interferometric measurements of refractive index changes of the culture medium. The bacteria-containing sample is kept in an isothermal block together with a reference liquid without bacteria. The biological activity is obtained from the difference of the index changes of these samples. Experiments were performed with Bacilo Calmette-Guérin. The order of magnitude of the observed total refractive index change was compatible with theoretical estimates based on the amount of available oxygen. An unexpected positive index change during the lag phase was observed, which might permit fast diagnostics in medical applications. This technique may provide cheap and quick tests of bacterial susceptibility with respect to antibiotics.

[Plasmodium falciparum malaria. Quadrennial analysis, during 12 years, of the efficacy of quinine treatment]. / Malária por Plasmodium falciparum. Análise quadrienal, durante 12 anos, da eficácia do tratamento com quinino.

The efficacy of quinine for the treatment of falciparum malaria was studied by quadriennal analysis of the medical records of 454 patients admitted to the HDT-GO from 1983 to 1994 and treated with identical doses of quinine alone for 7 days. In the quadriennium from 1983 to 1986, 98.4% of the patients became negative by the 5th day of treatment and 8% presented recurrence (R1); from 1987 to 1990, only 72.9% became negative by the 5th day of treatment, 1.4% remained positive until the 7th day (R2) and 9.7% presented recurrence (R1); from 1991 to 1994, 70.1% became negative by the 5th day of treatment, 3.5% remained positive until the 7th day (R2) and 20% presented recurrence (R1). The increase in parasite clearance time with failure up to the 7th day of treatment (R2) and the increase in recurrence (R1) show that P. falciparum is developing resistance to quinine in the region under study.