Cattle responses to small inclusions of lipids in the diet

The retention time of digesta in the rumen of cattle grazing tropical forages is long and extensive biohydrogenation occurs. The conjugated linoleic acid (CLA) levels that are found are low but would still result in a significant level in the products so formed. Many supplements contain low levels of lipids or even if found in a high concentration in the supplement, are fed at a low level with the end result being that the supplement cannot markedly change the fatty acid profile in the rumen fluid. Some small but significant changes can occur e.g. with coconut oil and fish oil. The level of CLA that is found and the likely level of inhibitory isomers of CLA suggest that this would not result in an inhibition of lipid synthesis especially given the long retention time and biohydrogenation of unsaturated fatty acids

Spittlebug damage on tropical grass and its impact in pasture-based beef production systems

Spittlebugs are the main pest of tropical pastures and Marandu palisade grass (Urochloa brizantha cv. Marandu) is the most representative cultivated pasture in the tropics. Our objective was to characterize Marandu palisade grass responses subjected to Mahanarva (Hemiptera: Cercopidae) attack and to estimate the losses in terms of beef production from pasture-based systems. A set of five experiments were carried out. Three consecutive years of monitoring showed that Mahanarva spittlebugs increased their abundance after first rains with three to four peaks throughout the wet season. A decrease of 66% on herbage yield was observed in the greenhouse trial, with an average decrease of 61% on pools of calcium, magnesium, phosphorus, sulfur, potassium, crude protein, neutral-detergent fiber and in vitro digestible dry matter of Marandu palisade grass. Results from field experiments corroborated with greenhouse trial showing decreases on herbage yield varying from 31 to 43% depending on level of fertilization and grazing severity of Marandu palisade grass. Finally, an unprecedented 154-ha field experiment indicated that Mahanarva decreases 74% the beef productivity (i.e. kg body weight ha-1) of Nellore heifers grazing Marandu palisade grass

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure <= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

Beef cattle responses to energetic supplementation on Marandu palisadegrass pastures subjected to rotational grazing with different stubble heights during the summer

Práticas adequadas de manejo do pastejo e de suplementação podem aumentar a produtividade e a competitividade de sistemas pastoris. Este experimento teve por objetivo avaliar o desempenho de bovinos de corte em pastos de capim-marandu submetidos a duas intensidades de pastejo rotativo (10 e 15 cm de resíduo) com e sem o uso de suplementação energética (0,6% do PV), entre 22 de dezembro de 2005 e 25 de maio de 2006. Foram utilizados 150 garrotes (80 marcadores e 70 ajustadores de taxa de lotação), provenientes de cruzamento industrial, com aproximadamente 220 kg e 8 meses de idade. A área experimental de 8,5 ha de pastagem de capim-marandu foi dividida em quatro módulos, com oito piquetes cada (2650 m2). Os pastos foram manejados com período de descanso variável, uma vez que o critério de entrada dos animais nos piquetes era a altura de 25 cm (equivalente a uma interceptação de luz pelo dossel de 95%) e a saída baseada nas alturas pós-pastejo de 10 e 15 cm. Os pastos foram adubados com 150 kg ha-1 de cloreto de potássio, 400 kg ha-1 de superfosfato simples e 30 kg ha-1 de FTE-BR12 (micronutrientes) antes do início do período experimental. Durante a fase experimental foi aplicado 2,5 kg de N. ha-1 dia-1 logo após o pastejo de cada piquete, sendo o período de descanso do ciclo de pastejo anterior utilizado como critério para determinar a quantidade de N aplicada. Foram avaliados: massa de forragem (MF) pré e pós pastejo (kg MS ha-1); composição morfológica (% de folhas, colmos e material morto) e valor nutritivo da forragem; ganho de peso individual (kg cab-1 dia-1); taxa de lotação (cab ha-1) e ganho de peso por área (kg ha-1). Não houve diferença no acúmulo de MS, composição morfológica da MF prépastejo e valor nutritivo da forragem do estrato pastejável entre os tratamentos de pastejo. A suplementação propiciou um ganho médio extra de 0,400 kg dia-1 nos dois tratamentos de pastejo. Os animais sem suplementação e mantidos nos pastos com altura pós-pastejo 10 cm apresentaram GPD baixo, 0,439 kg cab-1 dia-1. A suplementação desses animais propiciou GPD de 0,839 kg cab-1 dia-1. A suplementação com concentrado aumentou em aproximadamente 14% a taxa de lotação dos pastos manejados com a altura pós-pastejo 10 cm. Os pastos manejados com altura póspastejo 15 cm proporcionaram os maiores ganhos de peso por animal, tanto entre os não suplementados como entre os suplementados (0,548 e 0,960 kg cab-1 dia-1 respectivamente). Entretanto, a maior taxa de lotação e o maior ganho de peso por unidade de área, foram obtidos com os animais suplementados mantidos nos pastos manejados com a altura pós-pastejo de 10 cm. Para animais em recria mantidos em pastagens tropicais bem manejadas, a suplementação com concentrados energéticos, na dose de 0,6% do peso corporal, melhora o ganho de peso individual, a taxa de lotação dos pastos e o ganho por unidade de área, além de garantir peso mínimo para viabilizar a terminação dos animais em confinamento após a fase de recria.Adequate grazing management and supplementation practices can increase yield and economical competitiveness of the production system. The purpose of this work was to evaluate the performance of beef cattle on Brachiaria brizantha pastures (Marandu palisadegrass) subjected to rotational grazing managed with different stubble heights (10 vs 15cm), using an energetic supplement fed as 0 vs 0.6% LBW, from December 22nd of 2005 to May 25th of 2006. One hundred and fifty three cross breed non castrated calves were used (80 testers, and 70 stocking rate adjusters), averaging 220 kg of LBW, and 8 months old. The experimental area included 8.5 ha of Brachiaria brizantha pastures divided in four subareas, having 8 paddocks each, averaging 2650 m2. Resting intervals were different for each paddock, in order to achieve the target of grazing management: 25 cm of sward height at pre-grazing (equivalent to 95% interception of the incident light) and 10 or 15 cm at post-grazing, according to the treatment. Pastures were fertilized with 150 kg ha-1 of potassium chloride, 400 kg ha-1of superphosphate, and 30 kg ha-1 of FTE-BR12 (micronutrients) on October of 2005, prior to the experimental period. During the study, 2.5 kg of N ha-1day-1 were used right after grazing, with the resting period of the preceding cycle being used as criteria for the amount of N to be applied. The variables evaluated were: average daily gain (kg of LBW day-1), stocking rate (AU ha-1 period-1), system yield (kg of LBW ha-1 day-1), herbage mass on pre, and post grazing (kg DM ha-1), the morphological traits (stem, leaf, and senescent material percentages on the samples), and the nutritive value of the grazing horizon herbage. The supplemented animals gained an extra of 0.4 kg of LBW head-1 day -1 when compared to non supplemented, for both stubble height treatments. The animals kept on non supplement treatment with a 10 cm stubble height showed a low daily gain, of only 0.44 kg head-1. The supplementation of these animals promoted a satisfactory daily gain of 0.84 kg head-1. Supplementation increased on 14% the stocking rate (AU ha-1) of pastures managed with a 10 cm stubble height. The 15 cm stubble height treatment allowed higher daily gains for each animal, in both cases, supplemented, and non supplemented. However the highest stocking rates, and yield (ADG ha-1) were observed on the supplemented animals kept on 10 cm stubble height. For growing animals kept on well managed tropical pastures, energetic supplementation on a 0.6% of LBW amount improves daily gain, stocking rate, meat production per area, and assures a minimum weight that allows profitable finishing on a feedlot right after the growing period on pasture