Suchergebnisse

Este trabalho se propõe em monitorar quantitativamente a conversão no recorte espacial de uso e cobertura da terra na região central do Estado de Roraima, recorrendo de imagens captadas com sensores em satélites do programa LANDSAT 5 e 8, processando utilizando do sistema de informação geográfica (SIG) ArcGIS 10.1 R, para os anos de 1984,1994, 2004 e 2014 sucedendo em quatro mapas temáticos que serviram para identificação das classes de uso e cobertura da terra e cálculo da extensão da área em Hectares (ha).Tem-se como hipótese a existência de poucas classes de uso e cobertura da terra, principalmente floresta para o ano de 1984. No decorrer dos anos estudados foi possível perceber a conversão de áreas de floresta em pastagem. Partindo do pressuposto que Roraima é integrante da Amazônia Legal, o impacto da ação antrópica convertendo 29,14% correspondente a 135,691.18 ha de vegetação original em pastagem na imagem de 2014 explicita uma carência na fiscalização e um crescimento no mosaico do desmatamento. É proposto o estabelecimento de medidas de recuperação para as áreas que apresentaram certo padrão de regeneração da vegetação original.

O presente trabalho tem por finalidade, analisar quantitativamente se a evolução do uso do solo na região do Apiaú e vizinhanças no decorrer dos anos 1984, 1994 e 2014 tem relação com o tipo de solos presente na região. Para tal, utilizou-se o software Arcgis 10.1 e imagens LANDSAT 5 e LANDASAT 8. Confrontando o mapa temático de uso e cobertura com o de pedologia que foi digitalizado de uma folha digital (IBGE, 2005), observou-se que a classe de solo pouco influência na forma de uso e cobertura na região de estudo e que todos os solos das áreas são classificados como distróficos.

This study aimed to evaluate the inclusion of castor meal in the diet of lactating cows in grazing system and its implications in feeding behavior. Eight Holstein x Zebu crossbred cows, with average milk production adjusted to 300 days in the previous lactation, between 5000 and 6000 kg and 100.33 ± 13.33 days of lactation and average body weight of 509.47 ± 61.90 kg, were distributed in two 4 x 4 Latin squares, with 4 levels of castor meal inclusion in the total diet, and using Brachiaria brizantha pasture as roughage. The experiment consisted of four experimental periods, lasting 21 days each. In each trial, the roughage and supplements were collected for evaluation of chemical composition. Animals were subjected to visual observation for evaluation of feeding behavior for 24 hours, from the 20th to the 21st day of each experimental period. The observations of the activities were recorded every five minutes. We determined the number of ruminating chews and the time spent in rumination of each ruminal bolus with the use of digital stopwatch. There was a quadratic effect for the grazing time with maximum point of inclusion of castor meal at 4.61% in the diet; other variables did not differ: rumination, idleness, trough, rumination efficiency, feeding and grazing time, rumination and idleness. Castor meal can be included in the diet with levels up to 10%, for little changes in the feeding behavior of animals.

In this study, the feeding behavior of Nellore heifers receiving supplements containing mineral salt, conventional urea and slow release urea during the grazing stage at Brachiaria brizantha-based pastures during the dry period of the year was evaluated. Fifty-six heifers with approximately 284.72 ± 27.48 kg of body weight were used, distributed in a completely randomized design with four different treatment types: mineral salt; Urea - supplementation with 8.18% conventional urea; Mixed urea - supplementation with 4.09% conventional urea and 4.39% slow release urea and slow urea - supplementation with 8.78% slow release urea. Animals supplemented with mineral salt had longer grazing times compared to those supplemented with mixed urea, slow urea and regular urea. The dry matter intake, neutral detergent fiber and total digestible nutrients presented a similar effect, with higher values for heifers consuming supplements containing regular urea and slow urea compared to those of mixed urea. However, when the efficiency of hourly intake was evaluated, the animals that received urea supplement were more efficient in relation to the other treatments. The number of grazing periods for heifers receiving slow urea supplementation was higher compared to heifers receiving salt and mixed urea. The duration of grazing and rumination periods was longer for heifers receiving salt supplementation and mixed urea than those receiving regular urea and slow urea. It is recommended to use supplements at the level of 0.3% of body weight for heifers receiving conventional urea.

This study aimed to evaluate the inclusion of castor bean meal in the diet for lactating cows on Bracharia brizhanta pasture and its implications for nutritional and productive parameters. Eight crossbred cows were distributed in two 4 x 4 Latin squares, with four (0%; 3.33%; 6.66% and 10%) inclusion levels of castor bean meal in the total diet. The experiment consisted of four experimental periods of 21 days each. The digestibility and dry matter intake were estimated from fecal output, checked with the aid of external (chromium oxide) and internal (iNDF) indicators. Urine and milk were collected to determine the nitrogen balance and microbial protein production. The inclusion of different levels of castor bean meal in the diet for lactating cows did not affect the intake of dry matter and nutrients, and the same lack of effect was found for the digestibility of dry matter and total digestible nutrients, variation in body weight, milk production, chemical composition of milk, microbial production and nitrogen balance. The inclusion of up to 10% castor bean meal in the total diet did not influence productive parameters evaluated, and the use was conditioned to the price of castor bean meal.

This study evaluated the feeding behavior of lactating cows on pasture of Brachiaria (Urochloa) decumbens fed with concentrate supplementation containing different levels of castor meal inclusion treated with calcium hydroxide Ca (OH) 2, in the proportions of 0; 3.3; 6.6 to 10% of the total diet. Eight cows (degree of blood ½ to ¾ Holstein x Zebu), with previous average production of 3000-4000 kg adjusted to 300 days of lactation and average body weight of 465.16 kg ± 65.45 kg were distributed in two 4 x 4 Latin squares. The behavior was assessed every five minutes for 24 hours on the 21st day of each period. The results were tested by analysis of variance and regression at p < 0.05 probability. The time spent in grazing, rumination, idle and in the trough; total chewing time, number of cuds per day, chewing per day; chewing per cud; the number of periods of grazing, rumination, idle and in the trough; time spent by period of grazing, rumination, idle and in the trough were not different between treatments. The feed efficiency (g DM h-1; g NDFa h-1 and g TDN h-1) and time spent per cud ruminated TSR sec cud-1) were linearly reduced. It is recommended to include up to 10% castor meal treated with Ca (OH)2 in the total diet.

The modelling community has identified challenges for the integration and assessment of lake models due to the diversity of modelling approaches and lakes. In this study, we develop and assess a one-dimensional lake model and apply it to 32 lakes from a global observatory network. The data set included lakes over broad ranges in latitude, climatic zones, size, residence time, mixing regime and trophic level. Model performance was evaluated using several error assessment metrics, and a sensitivity analysis was conducted for nine parameters that governed the surface heat exchange and mixing efficiency. There was low correlation between input data uncertainty and model performance and predictions of temperature were less sensitive to model parameters than prediction of thermocline depth and Schmidt stability. The study provides guidance to where the general model approach and associated assumptions work, and cases where adjustments to model parameterisations and/or structure are required. (c) 2017 Published by Elsevier Ltd. ; Australian Research Council (ARC)Australian Research Council [DP130104078, LP130100756] ; GLM development and funding support for LCB, BDB, CB and MRH was provided by the Australian Research Council (ARC) (grants DP130104078 & LP130100756). Additional contributions from individuals and organisations as well as sources of data, provided from a variety of organisations are summarised in Appendix D. This study was made possible through the sharing of ideas, data and models across the AEMON and GLEON networks as well as discussions and working groups held during AEMON workshops and GLEON meetings. ; Public domain authored by a U.S. government employee