960 resultados para Altura de pastejo
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Objetivou-se avaliar o efeito de diferentes relações entre proteína verdadeira e nitrogênio não-proteico sobre a digestibilidade, a síntese de proteína microbiana e o balanço de compostos nitrogenados em bovinos em pastejo durante o período das águas. Foram utilizados cinco novilhos mestiços Holandês × Zebu, castrados, com peso vivo inicial de 335±35 kg fistulados no rúmen e no abomaso. Os tratamentos foram: controle (somente pasto); e suplementos com ureia; com 2/3 de compostos nitrogenados oriundos da ureia e 1/3 de compostos nitrogenados oriundos da albumina; com 1/3 de compostos nitrogenados oriundos da ureia e 2/3 de compostos nitrogenados oriundos da albumina; e com albumina. Foram fornecidos 200 g/dia de proteína bruta (PB) a partir dos suplementos. O experimento foi conduzido segundo delineamento em quadrado latino 5 × 5, com cinco períodos experimentais, cada um de 15 dias. A suplementação não afetou os coeficientes de digestibilidade total nem o teor de nutrientes digestíveis totais da dieta; elevou as estimativas do coeficiente de digestibilidade aparente ruminal da PB, que migraram de negativa, no tratamento controle, para positivas, porém não diferentes de zero, nos tratamentos envolvendo suplementação. O fornecimento de suplementos elevou a concentração de nitrogênio amoniacal ruminal. O balanço de compostos nitrogenados aumentou com a suplementação. A substituição de ureia por albumina influenciou de forma cúbica o balanço de compostos nitrogenados, cuja estimativa foi maior para o suplemento com 1/3 de PB oriunda da ureia. A eficiência de síntese microbiana no rúmen não foi influenciada pelo fornecimento ou pela composição dos suplementos. A suplementação de bovinos em pastejo com fontes de compostos nitrogenados degradáveis durante o período das águas amplia a eficiência de uso do pasto, principalmente por ampliar a retenção de compostos nitrogenados no organismo.
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O trabalho foi conduzido no Campus da Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal/UNESP com o objetivo de estudar o efeito de duas frequências (35 e 42 dias) e duas alturas do corte (15 cm e 30 cm do solo) sobre as características morfo-fisiológicas de recuperação, a produção e a composição bromatológica do capim-colonião (Panicum maximum Jacq.). Os resultados revelaram que plantas cortadas a intervalos de 42 dias apresentaram maior percentagem de perfilhos decapitados (53,70%), menor vigor de rebrota (918,89 kg de MS/ha/21 dias), porém maior produção de matéria seca (12.652,67 kg/ha). O vigor de rebrota mostrou melhor correlação com a percentagem de perfilhos decapitados (r = -0,60*), do que com os teores de carboidratos totais não estruturais da base do colmo (r = -0,04) e da parte subterrânea (r = -0,39). Com base nas produções de matéria seca e de proteína bruta, bem como, na composição bromatológica, o capim-colonião poderia ser cortado, no período de janeiro a abril, a intervalos de 42 dias, independentemente das alturas adotadas (15 cm ou 30 cm de solo).
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The objective was to study the physical attributes of an Oxisol under fallow or planted with tropical grasses under grazing. The experiment was conducted under the experimental design of randomized blocks in split-plot 2 x 5, being five types of use of soil (Brachiaria ruziziensis, Panicum maximum cv. Aries, Brachiaria brizantha cv. MG5, Panicum maximum cv. Mombaca and fallow) and two evaluation periods (after the first and after the second grazing), with four replications. We evaluated the characteristics of soil bulk density, total porosity, microporosity and macroporosity, after the first and second grazing, and soil resistance to penetration after the second grazing. In layer of 0.00 to 0.10 m, the macroporosity was affected by the interaction between types of use and evaluation periods, while the microporosity and total porosity were reduced and the density was increased from first to second evaluation time. In the subsurface layer (0.10-0.20 m), there were significant effect only of evaluation time, on the macroporosity, total porosity and density. The porosity were reduced, while the density increased from first to second evaluation time. No significant effects of types of use of soil on penetration resistance in all layers studied. The maintenance of an Oxisol under fallow or cultivation with tropical grasses subjected to grazing cattle causes a reduction in total porosity and increased density of surface soil layers (0 to 0.10 m) and subsurface (0.10 - 0.20 m), without promoting changes on resistance to penetration mechanics.
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The objective of this study was to evaluate two grazing intervals (IG) for elephant grass (Pennisetum purpureum Schum cv. Cameroon) pasture: one variable, determined by the entry of animals to the paddocks when 95% of active photosynthetic radiation was intercepted by the sward, and fixed 26-day grazing interval. Eight dairy cows were used, averaging 124 days lactation, 516 kg body weight and 17.5 kg daily milk production at the beginning of the trial. The experimental period was 80 days divided into four sub-periods of 20 days each. Data were analyzed in a cross-over design. The grazing frequencies did not influence milk production and composition, plasma urea nitrogen, body condition score and variations in body weight. However, the stocking rate and milk production per hectare were higher for pasture with interval of grazing determined by 95% of active photosynthetic radiation. Thus grazing frequency defined in variable intervals by sward interception of active photosynthetic radiation result in higher milk production per area unit.
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Infection due to the gastrointestinal nematodes can negatively interact with the productive performance of dairy goats, and in some cases can induce mortality in the flocks. The objective was to study the influence of season, parturition order, postpartum, lactation and breed standard on the population of helminths in dairy goats. 31 goats were used, with 15 Saanen and 16 F1 (1/2 Boer + 1/2 Saanen). of these, 13 were from the 1st lactation and 18 from the 2nd or more lactations. The highest fecal egg counts occurred during the summer and spring, with FEC in Saanen higher (p < 0.01) than in F1 animals (1/2 Boer + 1/2 Saanen). The animals with 1st lactation showed higher FEC (p < 0.004) than the animals in 2nd or more lactation. During the peripartum the largest FEC for both breeds standards were in the week of the birth (p < 0.05), followed by post-partum and pre-partum. In peripartum the Saanen goats showed higher FEC (p < 0.02) than the F1 and primiparous (p < 0.008) in relation to pluriparous. F1 animals are resistant to helminthes when compared to Saanen animals, demonstrating that crossing of resistant breeds with high production breeds is a viable alternative to increase productivity without compromising the parasitary stability of the herd. The peripartum period is a risk factor associated to the occurrence of gastrointestinal helminths, especially in Saanen goats from first lactation.
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Objective. To assess factors determining growth in a group of children between 3 months and 6 years old enrolled in a public municipal (i.e., government-supported, not private) day-care center, in comparison to a group of children with similar characteristics but who were not enrolled in the center. Methods. A quasi-experimental study was designed to observe 444 children aged 3 to 72 months from a low-income neighborhood in the city of Sorocaba, in the state of São Paulo, Brazil. Two groups were studied: 164 children enrolled in a local municipal day-care center (intervention group) and 280 not receiving care at the center (nonintervention, comparison group) but instead being cared for at home. Both groups were seen four times over a period of 16 months. At each observation session, the children's weight and height were measured. Information was also collected on the mother's sociodemographic characteristics and the illnesses she had suffered as well as the child's weight and other health characteristics at birth, the child's illnesses in the 15 days before each observation, and any hospitalizations. Results. The children in both groups were from low-income families, with 65% of the families having an average monthly income below US$ 100; 80% of the mothers had received 8 years of schooling or less. Multivariate linear regression analysis showed that at the first observation (just before enrollment in the day-care center), birth weight was the only factor that explained the nutritional differences between the two groups. Subsequent analyses showed that being in day care was the factor that best explained the differences between the groups, especially in terms of the adequacy of weight for age, after controlling for birthweight, sex, age at the beginning of the study, and illnesses in the 15 days before an observation session. The nutritional impact of the intervention was significant as early as 3 months after being enrolled in day care. Conclusions. The nutritional benefits of the care provided at the center outweighed the negative effects sometimes seen in such centers, such as the greater morbidity that children in day-care centers often experience in comparison to children receiving care at home.
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This work was carried out to evaluate different frequencies of supplementation during the dry season. Forty-eight Nellore steers with 320 kg of initial live weight were fed with Brachiaria brizantha cv. Marandu pasture on a continuous stocking rate. The animals were submitted to following treatments: Daily supplementation and supplementation three times a week. The animals in both treatments received 7 kg of supplementation animal -1 weekly, and were weighted at 28-day intervals. The data were analyzed by the MIXED procedure in SAS (2004), with measurements repeated over time. The study observed average forage allowance of 4.2 tons of DM ha-1, with 3.5% CP, 82.24% NDF and 64.97% ADF. There was no difference (p < 0.01) among daily weight gains of animals who received daily supplementation and those received supplementation three times a week (0.23 and 0.13 kg day -1, respectively). Therefore, the supplementation intervals did not influence steer performance during the dry season.
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The objective of this study was to evaluate the effect of supplemental protein during the rainy season on body growth, ingestive behavior and reproductive performance of crossbred Gir x Holstein dairy heifers, with mean age of 21 ± 4.1 months and average initial body weight of 296.7 ± 57.3 kg, distributed in a completely randomized design with four treatments and six replicates per treatment. Heifers remained on Brachiaria brizantha cv. Marandu pasture, managed according to a rotational grazing system and, as treatment, it was supplemented with protein concentrate (34%, 43%, 56% and 66% BW) and level of supply of 0.30% body weight (BW). The animals were weighed and the mean weight of the lot was used for the calculation of adjustment of the amount of concentrate offered. Heifers that reached 330.0 kg of live weight were artificially inseminated and, 45 days after insemination, pregnancy diagnosis was performed for the calculation of pregnancy rate and age at conception. No significant difference of protein levels was observed on grazing, eating behavior, productive performance and age at conception of dairy heifers on pasture. The average daily weight gain of BW and age at conception were, on average, 0.907 kg/animal and 24.03 months, respectively.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Were evaluated the economic effects of four grazing heights (20, 40, 60 and 80 cm) of Tanzânia grass for beef cattle. The total area was 12 acres divided into paddocks of one hectare, with three replications. We used three animals, males, Nelore per paddock, as more animals need additional adjustment to the height you want. The reduction in sward height allowed higher stocking rate, which, even with a reduction in individual performance, there was more beef production per area. The interest rate on capital given the property represented the largest share in the final cost of production. The participation of fixed variables showed a positive linear function of the increase in height from grazing, showing significant reduction of the production scale. A reduction in cost of production per hectare per year with increasing grazing height. No differences were found in certain economic indicators, and the four systems remunerate the capital invested.
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The aim of this study was to evaluate the effects of residual leaf area index (rLAI), years of evaluation and grazing cycles on the morphogenetic and structural characteristics of xaraés palisadegrass subjected to grazing intensities in two summers (years of evaluation). The experiment was carried out at the Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP, Campus de Jaboticabal, São Paulo, Brasil and the intensities of grazing were defined by four rLAI: 0.8, 1.3, 1.8 and 2.3. When the canopy intercepted 95% of incident light, the animals were placed on the pasture for grazing and kept until the rLAI target has been reached. Pastures were grazed by non-lactating Holstein cows (Bos Taurus Taurus L.), using the technique of mob-stocking. The morphogenetic and structural characteristics of xaraés palisadegrass respond effectively to weather conditions. There is variability in morphogenetic and structural characteristics in response to years and grazing cycles within years.