Productive and reproductive performance of heifers fed different levels of urea in the diet

The objective of the present study was to evaluate the nutrient intake, blood parameters, follicular diameter and performance of pre-puberty crossbred heifers fed isoproteic diets (14.1%CP) containing 0.0; 0.44; 0.88 and 1.32% urea on the total dry matter (DM) of the diet, with a 77:23 roughage:concentrate ratio. Twenty-four 18- month old heifers (Holstein x Zebu), 277.9 kg mean live weight (LW) were used, distributed in four treatments and six replications in a randomized complete design. The following were evaluated: dry matter intake (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), ether extract (EE), hemicellulose (HEM), plasmatic ureic nitrogen (PUN), plasmatic glucose, plasmatic total cholesterol, follicular diameter and daily weight gain (DWG). No influence of the urea levels in the diet was observed on NDF and HEM intake. A maximum intake was obtained of DM (8.75 kg day(-1)), CP (0.88 kg day(-1)), ADF (2.5 kg day(-1)) and EE (0.17 kg day(-1)) respectively for the levels 0.7, 0.8, 0.7 and 0.7% urea in total DM. The 0.6%; 0.77% and 0.6% urea levels in diet were the critical points for obtaining maximum response for the PUN (10.96 mg dL(-1)) and plasmatic glucose (84.97 mg dL(-1)) concentrations and, for follicular diameter (11.08 mm) on the 40(th); 24(th) and 31(st) day, respectively. The plasmatic total cholesterol concentration and DWG were not influenced by the urea added to the diet, with averages of 119.39 mg dL(-1) and 1.66 kg day(-1), respectively. It was concluded that urea can be added up to 1.32% on the total DM of the diet for pre-puberty crossbred heifers.

Avaliação da silagem de grãos úmidos de milho

This work had the objective of evaluating the effects of different percentages of corn (Zea mays L.) cob on the quality of the silage of high-moisture corn grains. The following treatments were studied: percentages of corn cob in the silage (0, 5, 10, 15 and 20%); period of sampling after opening the silos (zero, two, four and six days). The factorial arrangement 5 × 4 was studied according to a completely randomized block design with three replications. The variables studied were not affected by the sampling period. The buffering capacity and the pH were not affected by the cob, while the percent soluble carbohydrates and amoniacal nitrogen increasing until 1.2 and 1.89 unit percent, respectively. Increasing the amount of corn cobs reduced the contents of DM (from 63.9% to 58.6%), CP (from 10.0% to 7.3%), EE (from 4.87% to 3.92%) and the values of DMIVD (from 90.5% to 79.1%) in the silages and increasing the contents of acid detergente fiber (ADF) (from 3.3% to 12.9%) and neutral detergente fiber (NDF) (from 15.16% to 26.1%). The values of brute energy (BE) were not affected (P>0.01) by the cob corn in the silage.

Torta de dendê em dieta para a tilápia-do-nilo: Desempenho produtivo

To evaluate the nutritional value of African palm kernel meal (Elaeis guineensis) on the performance of Nile tilapia (Oseochromis niloticus), five isonitrogenous (30% crude protein), isoenergetic (2,800 Kcal/kg of digestible energy), and isofibrous (10% crude fiber) diets, with increasing levels of African palm kernel meal (0, 7, 14, 21, 28 and 35%) were fed ad libitum for 18 weeks to Nile tilapia (Oreochromis niloticus) fingerlings, averaging 1.52 ± 0.04 g of body weight, housed for 120 days in 60 liter aquaria with six fingerlings. To determine the production traits, weight gain, apparent food conversion, specific growth rate, protein efficiency ratio, weight gain percentage, net protein utilization, and body composition, fish were weighted at six-week intervals. Statistical analysis of recorded data were performed through multivariate profile analysis and polynomial regression models. Results showed that feeding fingerling Nile tilapia with ratios containing up to 35% of African palm kernel meal does not affect production performance.

Níveis de proteínas nas dietas de faisões em crescimento

The experiment with pheasants in initial growth phase (1 to 35 days of age), which had as its objective evaluating the nutritional needs of pheasants in the growth phase as to protein levels in the diets, was conducted on a pheasant farm located at Ribeirão Preto, SP, Brazil. Small pheasants were used, which were submitted to isocaloric diets containing 26%, 28% and 30% of crude protein. The experimental design was totally random with four repetitions of 30 birds per parcel, totaling 360 birds. The results showed that a 30% crude protein level should be recommended for pheasants in the growth phase (1 to 35 days of age).

Estabilidade física de péletes protegidos por diferentes produtos impermeabilizantes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aditivos na ensilagem do capim-elefante. I. Composição bromatológica das forragens e das respectivas silagens

The effect of the addition of ground ear corn with husks, wheat bran and saccharin, on the rate of 0, 8, 16 and 24% (dry weight of additive/wet weight of cut green grass), upon the chemical composition of both fodder and silage of Pennisetum purpureum Schum. cv. Guaçu was evaluated. A split-plot randomized block design was used. The plots were the additives and their levels and the sub-plots the material types (forage + additives and their silages). The grass was fertilized with 20 t/ha of green manure and 80, 160 and 160 kg/ha of P2O5, N and K2O, respectively. The material (chopped grass mixed with the levels of the additives) was ensiled in experimental silos (200 L plastic vessels). The dry matter percentages increased linearly as additive levels increased, being greater the effect of ground ear corn with husks. Wheat bran addition and saccharin increased the crude protein and soluble carbohydrates percentages while the ground ear corn with husks addition decreased them. Losses of dry matter soluble compounds (CP, ash and NFE) and a relative rise in the less soluble compounds (CF and organic matter) were observed.

Balance Preliminar de las Economías de América Latina y el Caribe 2006

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Balance Preliminar de las Economías de América Latina y el Caribe 2007

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Balance Preliminar de las Economías de América Latina y el Caribe 2011

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Implicaciones de la política macroeconómica, los choques externos y los sistemas de protección social en la pobreza, la desigualdad y la vulnerabilidad en América Latina y el Caribe: Nicaragua

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La inversión extranjera en México

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Contribución al crecimiento económico de las tecnologías de la información y las comunicaciones y de la productividad en la Argentina, el Brasil, Chile y México

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Dinámica del empleo y rotación de empresas: la experiencia en el sector industrial de Argentina desde mediados de los años noventa

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Política fiscal y protección social: sus vínculos en la experiencia chilena

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Rasgos estilizados de la relación entre inversión y crecimiento en América Latina y el Caribe, 1980-2012

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