994 resultados para Beef cattle breeds


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Pós-graduação em Zootecnia - FCAV

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Pós-graduação em Zootecnia - FCAV

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Pós-graduação em Genética e Melhoramento Animal - FCAV

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Genética e Melhoramento Animal - FCAV

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Pós-graduação em Genética e Melhoramento Animal - FCAV

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This experiment was conducted to evaluate the effect of grazing heights on daytime behavioral activities of Nellore beef cattle in the rainy season. The experimental area was 12 hectares divided into paddocks of one hectare each. The treatments consisted of four defoliation heights (15, 30, 45 and 60 cm) in pastures of Brachiaria brizantha cv. Xaraes with three replicates each. It was used the continuos grazing method, with variable stocking rate. Forage samples collected on the plots were sent to the laboratory for separation of the botanical components, weighing and determination of dry matter, with the material collected by simulated grazing. The variables: grazing time, idle time and ruminating time were evaluated for 12 consecutive hours on days 15 and 16 February 2011, considering the morning and afternoon periods. It was used a completely randomized design. The height of the canopy significantly influenced the daily grazing time and ruminating time, with a quadratic response as a function of time of defoliation. The bite rate decreased as a function of heights studied. However the chemical composition of the material collected by simulated grazing did not differ between treatments. Xaraes grass swards grazed at around 45 cm height provide greater ease of apprehension by grazing cattle.

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The objective of this study was evaluate the effects of immunocastration on body weight gain, carcass characteristics and meat quality of Nellore beef cattle. Eighty Nellore beef cattle, with initial body weight of 357 +/- 8.63 kg, were placed in feedlots and distributed in two treatments (40 animals per treatments) as follow: one - non-vaccinated bulls and two - immunocastrated bulls (Bopriva (R), Pfizer Animal Health). The animals placed on treatment two were vaccinated in two doses, first application 30 days before they arrive on the feedlots and second on the day they arrive on feedlots. After 67 days of experimental period, was calculated the daily gain of live weight in kg/day of the 80 animals and selected 20 animals from each treatment for the slaughter and carcass evaluations, and ten from each group for the meat analyzes. The data were submitted to analysis of variance. Immunocastrated animals showed lower daily weight gain, hot carcass weight, carcass yield, pH, leg thickness, muscle depth, loin muscle area, carcass muscle percentage, shear force and moisture. However, this animals had higher concentration of lactate and cortisol blood, chest depth, fat thickness, finishing degree, a *, b * and c*, liquid loss in thawing process, myofibrillar fragmentation index and ether extract of meat when compared to non-vaccinated bulss. The immunocastration (Bopriva (R)) is an alternative for improving the quality of meat by the higher fat deposition and by the reduction of the shear force of the meat when compared to non-vaccinated bulls.

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The objective of this study was to determine the best height of the Tanzania grass under grazing, assessing morphological and productive characteristics of the sward. This experiment was conducted in Cidade Gaucha, Parana, where he was rated the accumulation rate and morphological characteristics of Tanzania grass pastures grazed at 20, 40, 60 and 80 cm grazing under continuous stocking with variable stocking rate for beef cattle. The experimental area was 12 hectare divided in paddocks of one hectare each. For each paddock were allocated two grazing exclusion cage for estimating herbage accumulation, and eight samples were taken every 28 days throughout the year 2010. The completely randomized design. The herbage mass of the morphological structures showed a linear positive function of sward heights. The height of defoliation did not influence the rate of herbage accumulation for any of the morphological structures: green leaf, stem + sheaths and senescent material. There were also no differences in leaf: stem ratio. All heights within the range studied provided adequate number of green leaves per tiller. Tanzania grass pastures grazed under continuous stocking between 40 and 60 cm, for providing a good association between accumulation and mass of green leaf blades, and acceptable values of the mass of stem + sheaths and senescent material. Pasture of Tanzania grass under 60 and 80 cm allow of leaves satisfactory accumulation in the autumn.

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The age which heifers reach puberty depend on factors like genetics, environment and nutrition. Puberty in heifers can be defined as the onset of reproductive competence, the ability to ovulate a fertile oocyte with an estrous behavior and development of a corpus luteum with normal lifespan. The metabolic signals that trigger puberty are not yet fully defined. In Brazil, where most beef cattle are zebu, the age at puberty is very advanced, mainly these animals are feed with a poor diet. Many researches are trying to discover the metabolic signals that trigger puberty and anticipate better economic return in breeding farms. It has been demonstrated that the cascade of endocrine events that culminate in puberty can be hastened by an alternative management scheme that involves increased nutrient intake between 3 and 7 months of life. Different diet concentrations, different products and by-products have been used in research to achieve puberty early (less than 300 days of age). The hormonal induction of puberty, especially with the use of progestagens, has been developed in heifers as an alternative tool to improve reproductive efficiency in herds, increasing the amount of pregnant heifers in breeding season

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Escherichia coli O157:H7 is a foodborne pathogen associated with enteritis in humans, ranging from a mild to bloody diarrhea to hemolytic uremic syndrome, thrombotic thrombocytopenic purpura and even death. Large E. coli O157:H7 outbreaks have been reported worldwide and are frequently associated with consumption of undercooked beef. Cattle are a major reservoir of the pathogen, which is found in the intestinal tract of the animal. The carcasses can be contaminated with feces during the slaughter and production process. Ground beef remains the most common vehicle. The purpose of this study was to determine the E. coli O157:H7 importance associated to human illness and productivity losses to the meat industry, as well as identifying mechanisms of contamination related to beef and strategies to improve the safety of beef products

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When handling soil conservation practices isn’t applied correctly, they cause problems at the level of structure, cohesion and fertility in soils and lack of water availability. In the case of this monograph, conducted in a rural property located at Álvares Machado City, identified that most areas are intended for use activities of beef cattle and dairy and subsistence agriculture, which historically addition to withdraw native flora, resulting in problems such as compaction and increase soil exposure to climatic agents, generating a serious frame of erosion problems. In the case of water from rainfall, the soil exposed, causes the “splash” effect and therefore when it becomes runoff carries the spalled particles mainly for low land areas. Without the vegetation, especially trees or shrubs species, the velocity of runoff increases, initiating the appearance of furrows, which consequently may become a kind of ravine erosion and gully, which makes invalid any area in your surroundings... (Complete abstract click electronic access below)

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Pós-graduação em Medicina Veterinária - FCAV

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)