Glucose Metabolism in Steers Receiving High Fibre Diets and Glucose Infusion Into Abomasum

ABSTRACT: Glucose has been the subject of a number of studies due to as important role in ruminant metabolism. Nevertheless, there is paucity in the literature dealing with glucose metabolism when ruminants are offerred a low-quality roughages_ Eight Brahman steers approximately two years old and weighing 238 ± 23 kg were alloted randomly into an individual metabolism cage. Each steer received barley straw ad lib., 151) gld mineral mix and 75 g/d urea which was infused eontmously into the rumen. In addition to that, two steers were infused continously per abomasum with 1500 ml water/headid, whilst the remainders were infiised with 50, 100, 150, 200, 250 and 300 g/1500 mi/d anhydrous glucose during which die folloNving parameters were observed 7 feed consumption, rumen metabolites, nitrogen balance (NB). and metabolism of glucose. The last parameter was studied using a radio isotope technique. The results showed that aboniasal infusion of glucose significantly improved (130.01) the consumption of dry matter and organic matter as well as NB. The latter was associated with a significant reduction of urinary N excretion suggesting that there was a competition of glucose requirement on the expense of amino acid catabolism. There was no significant alteration (P>0. I) on the rumen metabolites attributable. to glucose infusion. Pool size of glucose was not altered by infusion but glucose entry rate (GER) and T 112 were linearly increased as the level of glucose infusion increased. The implication of this study is discussed in relation to practical app[icatiois with particular el nialiasis given to enhancement of niminant productivity on low-quality roughage. Key Words: Glucose. Metabolism, Barley Straw, Nitrogen Balanc

Performance of Braford steers grazing on cultivated pastures and fed or not fed an energy supplement

This experiment evaluated the performance of 84 Braford steers grazing on summer and winter cultivated pastures fed or not fed an energy-protein supplement. Steers were 10 months old and weighed, on average, 165 kg at the beginning of the trial. Steers grazed on cultivated winter pasture, consisting of black oats (Avena strigosa) and ryegrass (Lolium multiflorum Lam.), and then on cultivated summer pasture, consisting of Napier grass (Pennisetum purpureum). The following treatments were applied: SS - supplement was fed during both seasons; SN - supplement was fed only during the winter; NS - supplement was fed only during the summer; and NN - steers were not fed any supplement. Supplementation resulted in higher body weight and better body condition score (SS: 369.2 and 4.52; SN: 335.2 and 4.01; NS: 352.5 and 4.49; SS: 322.5 and 3.83). Longissimus dorsi area was larger in supplemented steers, which also presented thicker backfat when compared with those not fed any supplement (3.67 and 2.29 mm, respectively)

Suplementação como estratégia de produção de carne de qualidade em pastagens tropicais

O manejo do pastejo e a suplementação estratégica permitem maximizar a produção de carne bovina em pastagens de forma sustentável. A intensidade de pastejo influencia diretamente o crescimento individual, taxas de aparecimento e mortalidade de perfilhos, a determinar o acúmulo de forragem e a estrutura do dossel. Dessa forma, nas águas, é função do manejo do pastejo adequar a frequência e intensidade de desfolhação para que o animal possa colher forragem com idade fisiológica e valor nutritivo adequados. A idade e tamanho dos perfilhos determinam a proporção de tecidos de suporte lignificados que reduzem a digestibilidade da forragem. No período seco, o manejo do pasto e a estratégia de diferimento, ao final do período das águas, são determinantes na obtenção de forragem de melhor valor nutritivo. Assim, o manejo das pastagens visa, primeiramente, à produção de forragens com altos teores de fibra potencialmente digestíveis. A partir de então, a caracterização da quantidade e qualidade da forragem são primordiais à adequação dos nutrientes fornecidos, via suplementos, para otimizar a utilização dos recursos forrageiros basais. A suplementação da dieta dos animais em pastejo, com concentrado, permite aumentar o desempenho dos animais, o que reduz a idade de abate e melhora a qualidade da carcaça e da carne obtida, além dos benefícios na preparação dos animais terminados em confinamento. Portanto, o manejo do pastejo e a suplementação da dieta dos animais permitem aumento de produtividade e maior qualidade dos produtos.Grazing management and strategic supplementation can maximize the production of beef cattle on pastures in a sustainable system. Grazing intensity affects directly on individual growth, appearance and mortality rate of tillers, and also determines the herbage accumulation and canopy structure. During the rainy season is a function of grazing management to adapt the frequency and intensity of defoliation, to supply the animal with forage in an appropriate physiological stage and nutritive value. The age and size of tillers determine the proportion of lignified tissues that will reduce the digestibility of forage. During dry season, the stockpiled pasture strategies at the end of the rainy season, will be crucial to obtaining forage of highest nutritive value. The pasture management primarily aims to produce forages with high levels of potentially digestible fiber. Since then, the characterization of the forage quantity and quality are essential to adjusting the nutrients supplied by supplements to optimize the available forage utilization. Supplementation of grazing beef cattle with concentrate can increase animal performance, reduce the slaughter age, and improve the quality of carcass and meat. Moreover, it has benefits in the preparation of the animals that will be finished in feedlot, and reducing this phase. Therefore, grazing management and supplementation of the animal diet should increase productivity, and improved carcass and beef quality.Universidade Estadual Paulista Faculdade de Ciências Agrárias e VeterináriaUniversidade Estadual Paulista Faculdade de Ciências Agrárias e Veterinária Programa de Pós Graduação em ZootecniaUniversidade Federal de Lavras (UFLA) Departamento de ZootecniaUniversidade Estadual Paulista Faculdade de Ciências Agrárias e VeterináriaUniversidade Estadual Paulista Faculdade de Ciências Agrárias e Veterinária Programa de Pós Graduação em Zootecni