57 research outputs found

    Classification, characterisation and strategies for improvement of cattle and sheep pasture systems in marginal areas of Southern Chile

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    Pasture-based livestock systems in farms with medium or low size are especially important in less favored areas and are valuable for society. For these systems to survive, it is necessary to obtain an acceptable level of productivity and ensure commercialization of the products. This study was carried out in the district of Rio Ibáñez, General Carrera Province, in the XI (Aysén) Region of Chile. The sample consisted of 28 small-scale livestock farmers with dual-purpose cattle production; 16 of them also produced sheep for meat. The empirical data produced 55 variables which were subjected to multivariate analysis; three main components were obtained which explain 72.1 % of the variance. By cluster analysis it was obtained four groups with characteristics which varied by farm size, age and personal situation of farmers, farm management and farm profitability. The principal problems found are low productivity in the herds and the poor marketing channels of animals produced. In two groups, due to the low size and poor management, the profitability of the farms is very low and this may compromise their future. To improve production systems, the training and advice of farmers should be strengthened, investment should be supported, especially for young people, and the farmer partnership should be promoted. There is also a need to diversify the families' sources of income (sale of other farm products or handicrafts and touristic activities).Ministerio de Economía de Chile Innova-CORFO Project 11 NTEC 1279

    Classification, characterisation and strategies for improvement of cattle and sheep pasture systems in marginal areas of Southern Chile

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    Pasture-based livestock systems in farms with medium or low size are especially important in less favored areas and are valuable for society. For these systems to survive, it is necessary to obtain an acceptable level of productivity and ensure commercialization of the products. This study was carried out in the district of Rio Ibáñez, General Carrera Province, in the XI (Aysén) Region of Chile. The sample consisted of 28 small-scale livestock farmers with dual-purpose cattle production; 16 of them also produced sheep for meat. The empirical data produced 55 variables which were subjected to multivariate analysis; three main components were obtained which explain 72.1 % of the variance. By cluster analysis it was obtained four groups with characteristics which varied by farm size, age and personal situation of farmers, farm management and farm profitability. The principal problems found are low productivity in the herds and the poor marketing channels of animals produced. In two groups, due to the low size and poor management, the profitability of the farms is very low and this may compromise their future. To improve production systems, the training and advice of farmers should be strengthened, investment should be supported, especially for young people, and the farmer partnership should be promoted. There is also a need to diversify the families' sources of income (sale of other farm products or handicrafts and touristic activities).Ministerio de Economía de Chile Innova-CORFO Project 11 NTEC 1279

    Conjugated linoleic acid content in milk of Chilean Black Friesian cows under pasture conditions and supplemented with canola seed (Brassica napus) concentrate

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    At present, there is limited and contradictory information about the effects of the use of canola (Brassica napus) seed as supplement on the contents of conjugated linoleic acid (CLA) in milk of grazing cows. The objective of this study was to evaluate the effect of a dietary supplement with canola seed on the production and composition of milk, and CLA concentration in Chilean Black Friesian cows under pasture conditions. Three experiments were done. Experiment 1: control group was fed 5 kg d–1 of commercial concentrate without canola (0-TC1) and treatment group that was fed 3.75 kg of commercial concentrate plus 1.16 kg of whole canola seed (1.16-TC1). Experiment 2: Control group was fed 8 kg d–1 commercial concentrate without canola (0-TC2) and treatment group that was fed 6.2 kg of commercial concentrate plus 1.2 kg of ground canola seed (1.2-TC2). Experiment 3: control group was fed 6 kg d–1 commercial concentrate without canola (0-TC3) and treatment group was fed 6 kg of commercial concentrate with 20% of whole canola seed (1.2 kg d–1, 1.2-TC3). The duration of each experiment was 60 days. No differences in milk production and quality were observed among the experimental groups in every assay. The CLA isomers trans-10, cis-12 and cis-10, cis-12 were higher than those normally found in the scientific literature. There was no effect of the inclusion of canola seed on total CLA content or the content of cis-9, trans-11, trans-10, cis-12 and cis-10, cis-12 isomers

    Estimación de las relaciones genéticas entre razas caprinas españolas y criollas utilizando microsatélites

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    We have analyzed three Creole goat populations from Peru, Mexico and Chile using microsatellite markers. We have also analyzed the genetic relationship between them and Murciano-Granadina and Malagueña Spanish goat breeds. The average number of alleles per locus was similar in all populations (7.3) except the Chilean Creole (5.1). This Creole goat population has presented the lowest value of observed (Ho) (0.53) and expected (He) heterozygosis (0.59). The Peruvian Creole has presented the highest values of Ho (0.70) and He (0.71). We have found a scarce level of genetic differentiation between goat populations (FST= 0.069) being more important the individual genetic differences due to crossbreed with several breeds. The Peruvian Creole was closed to analyzed Spanish breeds, followed by Mexican Creole. Finally the Chilean Creole was the most distant to the others populations

    Assessment of a Sand Spit Morphodynamics Under Extreme Flood Events

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    &lt;p&gt;Spits are landforms that present a complex morphology, which depends on currents, waves, sediment transport, tidal range and anthropic-induced changes. Their position and shape is subject to extreme events like flood river discharges and storms. They can also respond to processes that take place at larger time scales, as plate tectonics, sea level rise or even climatological patterns with teleconnections all over the world, as the well know North Atlantic Oscillation (NAO) or El Ni&amp;#241;o-Southern Oscillation (ENSO). This is the case of the Douro river mouth sand spit located on the northern coast of Portugal. This naturally dynamic sand spit, which has moved landwards over the past decades, has caused frequent nuisance to navigation, affecting width and depth of the navigation channel. Therefore, a breakwater was constructed in an attempt to stabilise the sand spit and the estuary inlet.&lt;/p&gt;&lt;p&gt;Validated hydrodynamic numerical models (openTELEMAC-MASCARET and Delft3D) of the Douro river estuary have demonstrated ability to accurately describe the estuarine hydrodynamic patterns and water elevation under extreme flood conditions. Model results showed that for higher river flow discharges the sand spit is partially inundated.&lt;/p&gt;&lt;p&gt;In this work a morphodynamic model (Delft3D) of the estuary was implemented to assess both the morphodynamics of the sand spit under extreme events, including the effect of sea level rise due to climate change, and the variation of extreme water levels along the estuary due to spit erosional processes that can occur during flood events.&lt;/p&gt;&lt;p&gt;Preliminary results show that the sand spit will be locally eroded for the higher river flood discharges, forming a two-secondary-channels system, with one channel located near the breakwater&amp;#8217;s southern extremity and the other, narrower, near the south bank. Associated with these two channels, two depositional bars will be formed in front of the channels at the coastal platform. However, the inner immersed sand spit will be suffering a sedimentation process for all of the simulated scenarios. This way, neither the river mouth discharge conditions nor the water levels inside the estuary will suffer significant changes according to the simulated scenarios.&lt;/p&gt;&lt;p&gt;These results will be complemented with further analyses considering the sediment size influence, tidal level, storm surge, sea level rise and river flood discharges.&lt;/p&gt;&lt;p&gt;Acknowledgements: To the Strategic Funding UIDB/04423/2020 and UIDP/04423/2020 (FCT and ERDF) and to the project EsCo-Ensembles (PTDC/ECI-EGC/30877/2017, NORTE 2020, Portugal 2020, ERDF and FCT). The authors also want to acknowledge the data provided by EDP and IH.&lt;/p&gt;</jats:p

    Estimation of genetic relationships between Spanish and Creole goat breeds using microsatellite

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    Ponencia publicada en ITEA, vol.104Se han analizado genéticamente tres poblaciones caprinas Criollas de Perú, México y Chile utilizando marcadores de ADN de tipo microsatélite y se han comparado con las razas españolas Murciano Granadina y Malagueña. Se ha encontrado un número medio de alelos por locus similar en todas las poblaciones (7,3) excepto la población Criolla Chilena que ha mostrado un valor de 5,1, siendo ésta la que ha presentado el valor inferior tanto de heterocigosidad observada (Ho) (0,53) como de esperada (He) (0,59), habiendo sido la Criolla Peruana la que ha presentado los mayores valores (0,70 y 0,71 respectivamente). Se ha encontrado un escaso nivel de diferenciación genética entre las poblaciones (FST = 0,069) siendo las diferencias encontradas debidas a los individuos como consecuencia al cruzamiento indiscriminado con otras razas. La población caprina Criolla de Perú es la que más se aproxima gené- ticamente a las 2 razas españolas analizadas, seguida de la Criolla Mexicana, por último la población criolla Chilena es la que presenta la mayor lejanía genética con el resto de poblaciones estudiadas.We have analyzed three Creole goat populations from Peru, Mexico and Chile using microsatellite markers. We have also analyzed the genetic relationship between them and Murciano-Granadina and Malagueña Spanish goat breeds. The average number of alleles per locus was similar in all populations (7.3) except the Chilean Creole (5.1). This Creole goat population has presented the lowest value of observed (Ho) (0.53) and expected (He) heterozygosis (0.59). The Peruvian Creole has presented the highest values of Ho (0.70) and He (0.71). We have found a scarce level of genetic differentiation between goat populations (FST= 0.069) being more important the individual genetic differences due to crossbreed with several breeds. The Peruvian Creole was closed to analyzed Spanish breeds, followed by Mexican Creole. Finally the Chilean Creole was the most distant to the others populations

    Future estuarine circulation patterns characterization based on a hydrodynamic models ensemble

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    &lt;p&gt;Estuarine regions are strategically important from an environmental, economic, and social point of view. To reduce vulnerability and increase resilience, it is crucial to know their dynamics that usually are poorly understood. Numerical models have proven to be an appropriate tool to improve this knowledge and simulate scenarios for future conditions. However, as the modelling results may be inaccurate, the application of the ensembles technique can be very useful in reducing possible uncertainties. In the EsCo-Ensembles project, this technique is proposed to improve hydrodynamic predictions for two Portuguese estuaries: Douro and Minho.&lt;/p&gt;&lt;p&gt;Two already validated numerical models (openTELEMAC-MASCARET and Delft3D), which have demonstrated their ability to accurately describe estuarine hydrodynamic patterns and water elevation for river flow in normal and extreme conditions, were applied. Several scenarios for climate change effects were defined including river flood peak flows for the 100 and 1000 year return periods and sea level extreme values for RCPs 4.5 and 8.5 in 2100.&lt;/p&gt;&lt;p&gt;The results demonstrated a clear difference between the hydrodynamic behaviour of the two estuaries. Model outcomes for the Minho estuary, which is dominated by the tide and therefore by oceanographic conditions, show a pronounced effect of rising sea levels on estuarine hydrodynamics. Whereas, for the Douro estuary, which is heavily dominated by the river flow, the effect of the sea level rise is hardly noticeable during flood events.&lt;/p&gt;&lt;p&gt;These and further results of this ongoing project are expected to (i) provide a complete hydrodynamic characterization of the two estuaries; (ii) evaluate future trends; (iii) estimate the flood risks associated with extreme events and (iv) demonstrate that the combined use of different models reduces their uncertainty and increases the confidence and consistency of the forecasts.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Acknowledgements: &lt;/strong&gt;To the Strategic Funding UIDB/04423/2020 and UIDP/04423/2020 (FCT and ERDF) and to the project EsCo-Ensembles (PTDC/ECI-EGC/30877/2017, NORTE 2020, Portugal 2020, ERDF and FCT). The authors also want to acknowledge the data provided by EDP, IH and Confederaci&amp;#243;n Hidrogr&amp;#225;fica Mi&amp;#241;o-Sil.&lt;/p&gt;</jats:p
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