RESUMO -Foram avaliadas as características da biomassa do capim-tanzânia sob três frequências de desfolhação (85, 95 e 97% da interceptação da radiação fotossinteticamente ativa -IRFA) e dois resíduos pós-pastejo (índices de área foliar residual de 1,0 e 1,8) em delineamento inteiramente casualizado em arranjo fatorial 3 × 2, com quatro repetições. O maior período de descanso foi verificado para o menor resíduo pós-pastejo e a frequência com 97% de IRFA. Observou-se uma altura elevada, assim como maior IAF para a frequência com 97% de IRFA. Já no caso da densidade populacional de perfilhos (DPP) e no nº de folhas/perfilho, ocorreu uma interação entre os fatores, com uma redução nos seus valores nos pastos manejados com IAF residual de 1,8. As massas de forragem, com exceção da forragem morta, foram fortemente influenciadas pela frequência de desfolhação, mostrando maior produção para frequência de desfolhação com 95% de IRFA. A interceptação luminosa no residual, assim como a altura nessa condição, foram maiores para o maior resíduo pós-pastejo.A DPP residual apresentou interação entre os fatores com redução no perfilhamento nas freqüências 85 e 95% de IRFA no

RESUMO -Objetivou-se avaliar a composição químico-bromatológica, a digestibilidade e a degradação in situ da matéria seca da dieta consumida por ovinos em pastagem de Panicum maximum cv. tanzânia sob três frequências de desfolhação, determinadas pela interceptação da radiação fotossinteticamente ativa (IRFA) de 85, 95 e 97% no 1 o e 4 o dias de pastejo. O delineamento experimental foi inteiramente casualizado com arranjo fatorial 3 × 2 (três frequências de desfolhação e dois dias de pastejo), com quatro repetições (piquetes) por tratamento. Para determinação da composição químico-bromatológica e da digestibilidade e ensaio de cinética de degradação da matéria seca da dieta, foi realizada uma simulação de pastejo no 1 o e 4 o dias de ocupação. A diminuição da frequência de desfolhação piorou a composição químico-bromatológica, a digestibilidade e a degradação do capim-tanzânia. Recomenda-se frequência de desfolhação no capim-tanzânia menor ou igual a 95% de interceptação da radiação fotossinteticamente ativa visando à manutenção da qualidade do pasto.Palavras-chave: interceptação da radiação fotossinteticamente ativa, Panicum maximum, sistema de produção Chemical composition, digestibility and in situ degradation of sheep diet on Tanzania grass with three defoliation frequencies ABSTRACT -The objective of this study was to evaluate the chemical composition, digestibility and in situ degradation of dry matter of the diet consumed by sheep grazing on Panicum maximum cv. Tanzania under three defoliation frequencies, determined by the interception of the photosynthetically active radiation in the canopy (PAR) of 85, 95 and 97% on the first and fourth days of the grazing period. A randomized complete design in a 3 × 2 factorial arrangement (three defoliation frequencies and two days grazing), with four replications (poles). To determine the chemical composition, digestibility and an in situ dry matter degradation trial, a grazing simulation was carried out on the 1 st and 4 th days. Reduced defoliation frequency decreased the chemical composition, digestibility and in situ degradation of the diet. Thus defoliation frequency of tanzania grass is recommended of less or equal to 95% photosynthetically active radiation to maintain pasture quality.Key Words: Panicum maximum, photosynthetically active radiation interception, production system Introdução A qualidade de uma planta forrageira é definida como sua capacidade em gerar desempenho animal, portanto, inclui composição química, digestibilidade, consumo voluntário e interação de fatores hereditários e de ambiente (Mott, 1970;Moore, 1994). Então, a qualidade do alimento é uma combinação de características variadas que vão desde a composição químico-bromatológica até a forma como este alimento está disponível aos animais em pastejo.Com o avançar da idade, ocorre o enrijecimento das folhas, especialmente em sua base, e dos colmos, em decorrência do aumento de compostos estruturais (Hodgson, 1985). Reduzem ainda o teor de proteína bruta e a digestibilidade, podendo limitar...

Agroforestry systems (AFS) are considered alternative land use options to help prevent soil degradation and improve soil microbial biomass and organic C status. However, it is unclear how different densities of babassu palm [Attalea speciosa (syn. Orbignya phalerata)], which is an important tree in Northeast Brazil, affect the soil microbial biomass. We investigated the soil microbial biomass C and activity under AFS with different densities of babassu palm associated with Brachiaria brizantha grass. Soil microbial biomass C (MBC), soil microbial biomass N (MBN), MBC:total organic C ratio, fluorescein diacetate hydrolysis and dehydrogenase activity showed highest values in plots with high density of babassu palm. On the other hand, the respiratory quotient (qCO 2 ) was significantly greater in plots without babassu palm. Brachiaria brizantha in monoculture may promote C losses from the soil, but AFS with high density of babassu palm may increase the potential of soils to accumulate C. ResumenLos sistemas agroforestales (AFS, por sus siglas en inglés) son opciones alternativas de uso de la tierra que ayudan a prevenir la degradación del suelo y mejorar la biomasa microbiana y el estado del carbono (C) orgánico. Babasú [Attalea speciosa (syn. Orbignya phalerata)] es una importante palma nativa que forma bosques en los estados Maranhão y Piauí, nordeste de Brasil; no obstante no se conoce su efecto sobre la biomasa microbiana del suelo cuando crece en diferentes densidades. En el estudio se evaluaron los efectos sobre el C y la actividad de la biomasa microbiana del suelo en AFS con 3 densidades de babasú en pasturas de Brachiaria brizantha. El C y el nitrógeno de la biomasa microbiana (MBC resp. MBN) del suelo, la relación de MBC:C orgánico total del suelo, la hidrólisis de diacetato de fluoresceína y la actividad de la deshidrogenasa mostraron valores más altos en las parcelas con alta densidad de babasú. Por otra parte, el cociente respiratorio (qCO2) fue significativamente mayor en las parcelas sin babasú. El pasto B. brizantha en monocultivo puede promover la pérdida de C del suelo, pero los AFS con alta densidad de la palma pueden aumentar el potencial de los suelos para acumular C.

Haemonchus contortus is the most prevalent nematode in tropical and subtropical regions and is responsible for significant losses in small ruminant production systems. Control of this parasite is based on the use of synthetic anthelmintics; although effective, prolonged and indiscriminate use can select for populations of resistant nematodes. Hydrolyzed yeast can help prevent populations of nematodes and is low in cost. The present study aimed to evaluate the preventive effect of hydrolyzed yeast on H. contortus through in vitro and in vivo assays. In in vitro experiments, the yeast preparation was tested at different stages of the H. contortus life cycle via tests of egg hatchability, larval development, larval exsheathment and larval migration. Both eggs and L3 larvae were obtained from sheep artificially infected with a monospecific strain of H. contortus. In in vivo experiments, animals were treated with hydrolyzed yeast (53.4 mg/kg/BW), and fecal egg counts (FECs), feces culture and Famacha were performed. The yeast preparation inhibited larval exsheathment in a dose-dependent manner (IC of 0.46 mg/mL), though no activity at the other stages of the H. contortus life cycle was observed. The hydrolyzed yeast preparation was able to reduce FECs in treated animals from D40 to D54 (p < 0.05), showing an average efficiency of 60%. The yeast exhibited preventive properties, and the IC value suggests that H. contortus is highly susceptible. Our results indicate that administration of hydrolyzed yeast, which is already used commercially in ruminant nutrition, is an alternative method for the control of nematodes, mainly H. contortus.

-The objective of this work was to evaluate the quality of pasture and enteric methane (CH 4 ) emission of Curraleiro Pé-duro x Nellore cattle in a pasture of Megathyrsus maximus 'Mombaça', both in full sun and in a consortium with babassu palms (Attalea spp.) in the Amazonian biome. The experimental design was completely randomized, with six steers per system, and the evaluations were done during the dry period (2015) and rainy period (2016). In comparison to forage in the full sun system, forage in the silvopastoral system showed, in the dry period, higher levels of crude protein, ether extract, total digestible nutrient, and in vitro digestible organic matter, and lower levels of dry matter, neutral detergent fiber, and total carbohydrate (TCHO). In the rainy period, forage in the silvopastoral system showed higher levels of crude protein and a reduction of nonfibrous carbohydrate and TCHO. The CH 4 emissions were similar in both systems within the same period, and ranged from 44.0 to 74.2 kg per year per animal. During the dry period, the emission per kilogram of dry ingested matter and the loss of gross energy as methane were lower in the silvopastoral system. During the rainy period, the emissions were similar in both systems. The silvopastoral system yields forage with good quality in the dry period, and considering both periods, it is more efficient (emission of CH 4 per daily weight gain) than the system in full sun. Index terms: CH 4 , Curraleiro Pé-duro, greenhouse gases, livestock farming, Nellore. Metano entérico de bovinos em pastagem a pleno sol e em sistema silvopastoril na AmazôniaResumo -O objetivo deste trabalho foi avaliar a qualidade da pastagem e a emissão de metano (CH 4 ) entérico de bovinos Curraleiro Pé-duro x Nelore, em pastagem de Megathyrsus maximus 'Mombaça', tanto a pleno sol como em consórcio com palmeiras de babaçu (Attalea spp.), no bioma Amazônia. O delineamento experimental foi inteiramente casualizado, com seis novilhos por sistema, e as avaliações foram realizadas nos períodos seco (2015) e no chuvoso (2016). Em comparação à forragem no sistema a pleno sol, a forragem no sistema silvopastoril apresentou maiores teores de proteína bruta, extrato etéreo, nutrientes digestíveis totais e digestibilidade in vitro da matéria orgânica, e menores teores de matéria seca, fibra em detergente neutro e carboidratos totais (CHOT). No período das águas, o sistema silvopastoril apresentou maiores teores de proteína bruta e reduções de carboidratos não fibrosos e CHOT. As emissões de CH 4 foram semelhantes entre os sistemas, tendo variado de 44,0 a 74,2 kg por animal por ano. No período seco, a emissão por quilograma de matéria seca ingerida e a perda de energia bruta por metano foram menores no sistema silvopastoril. No período chuvoso, as emissões foram similares entre os tratamentos. O sistema silvopastoril oferece pastagem de boa qualidade na seca e, considerando-se o ciclo com ambos os períodos, é mais eficiente (emissão de CH 4 pelo ganho de peso diário) do que o sistema a ...

Gastrointestinal nematodes (GINs) cause considerable economic losses in grazing goat herds. At present, GIN control cannot rely on conventional anthelmintic (AH) drugs because parasites have developed resistance against such drugs. Thus, alternative control methods are being sought to reduce the dependence on AH. Many tannin-rich plants exhibit AH activity and may be used as alternatives for GIN control. Mimosa caesalpiniifolia is a tannin-rich shrub consumed by small ruminants in Brazil. This study evaluated the in vivo AH effect of M. caesalpiniifolia leaf powder supplementation on GIN egg fecal excretion and worm burden in goats. Plant leaves were harvested, dried and ground to obtain a powder. Twenty-four castrated male goats, aged six to eight months, with a mean body weight of 15.0 ± 2.5 kg were used in the experiment. Animals were infected orally with 16,000 larvae comprising 50% Haemonchus spp., 41% Trichostrongylus spp. and 9% Oesophagostomum spp. Once the infection was patent, the goats were distributed into four groups of six animals. The control group received concentrate without condensed tannins (CTs) and did not receive any drench against GINs. The monepantel group received concentrate without CTs and were drenched once with monepantel. The other two groups received the M. caesalpiniifolia leaf powder in two periods of seven consecutive days (days 1-7 and 14-21), with one of the groups also receiving 10 g of polyethyleneglycol (PEG)/day. The animals were weighed weekly, and individual fecal eggs counts (FECs) were performed daily. After 28 days, the animals were humanly slaughtered, and the worm burden was estimated. Although live weight gain and FECs did not differ among the groups (P > 0.05), post-mortem worm counts showed a reduction in Haemonchus contortus adult worm burden (57.7%) in goats of the CT group compared to control goats (P < 0.05). The addition of PEG did not diminish AH activity in the CT + PEG group (66.9% reduction compared to the control). No AH effect against other GIN species was found. The result for the addition of PEG suggested that the observed AH activity was associated with plant secondary compounds, as opposed to CTs. As expected, no AH effect against Oesophagostomum columbianum was found for the monepantel group showed. Thus, feeding dry leaves of M. caesalpiniifolia represent a promising alternative for the control of GIN infections in goats.

Rev. Bras. Saúde Prod. Anim., Salvador, v.15, n.4, p.815-826 out./dez., 2014 Accumulation of forage and sward structure of Xaraés grass subjected to intensity of cuts

-Biomass flow characteristics and forage accumulation were evaluated in Bermudagrass (Tifton 85) pasture managed under intermittent stocking with different management strategies. The management levels utilized were conventional (10 cm residual height and unfertilized), light (20 cm residual height and unfertilized), moderate (20 cm residual height with fertilization of 300 kg N/ha.year) and intensive (10 cm residual height with fertilization of 600 kg N/ha.year). A randomized design was used with repeated measurements over time, in two periods of the year, with four replicates. There was significant effect of management × period of the year on the leaf elongation rate (LER). The management levels under fertilization (0.59 and 0.60 cm/tiller.day for the intensive and moderate management, respectively) and the rainy season (0.49 cm/tiller.day) showed the greatest stem elongation rate. Leaf senescence rate (LSR) before and after and total LSR were modified by the management × period of the year interaction. The intensive management, with 0.38 leaves/tiller. day, as well as the dry period, with 0.27 leaves/tiller.day, showed higher leaf appearance rate. The lowest phyllochron was observed in intensive management and dry periods, as well as an interaction with the management of the same periods of the year. There was management × period of year interaction effect on leaf lifespan; the highest value was found under conventional management and dry period. Both production and forage accumulation rates were higher in the intensive and moderate management levels and dry season, and there was interaction of the intensive management system with the seasons. Managing pastures under moderate and intensive rotational stocking, which occurred mainly in the rainy and dry seasons, respectively, maximizes the flow of tissues and consequently production and accumulation of forage.