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Pasture
Kinds of Pasture Terms modified by Pasture Selected AbstractsHigh levels of grass pollen inside European dairy farms: a role for the allergy-protective effects of environment?ALLERGY, Issue 7 2009B. Sudre Background:, There is evidence of an allergy protective effect in children raised on farm. It has been assumed that microbial exposure may confer this protection. However in farm, little attention has been given to the pollen level and to concomitant microbiological exposure, and indoor pollen concentrations have never been precisely quantified. Methods:, The kinetics of pollen in dairy farms have been studied in a pilot study (n = 9), and exposure in a sub-sample of the ongoing European birth cohort PASTURE (n = 106). Measurements of viable microorganisms and pollen were performed in air samples. To identify factors that modulate the pollen concentration multivariate regression analyses were run. Results:, Indoor pollen (95% of Poaceae fragments and grains) were significantly higher in winter than in summer (P = 0.001) and ranged between 858 to 11 265 counts/m3 during feeding in winter, thus exceeding typical outdoor levels during the pollen season. Geometric mean in French farms was significantly higher than in German and Swiss farms (7 534, 992 and 1 079 count/m3, respectively). The presence of a ventilation system and loose housing systems significantly reduced indoor pollen levels. This pollen concentration rise after feeding was accompanied by an increase in fungal and actinomycetal levels, whereas the concentration of bacteria was not associated with feeding. Conclusions:, Farmers and their children who attend cowsheds during the feeding sessions are exposed perennially to high pollen concentrations. It might be speculated that the combined permanent exposure to microbes from livestock and grass pollen may initiate tolerance in children living on a farm. [source] Gene expression measurements in the context of epidemiological studiesALLERGY, Issue 12 2008C. Bieli Background:, Gene expression measurements became an attractive tool to assess biological responses in epidemiological studies. However, collection of blood samples poses various technical problems. We used gene expression data from two epidemiological studies to evaluate differences between sampling methods, comparability of two methods for measuring RNA levels and stability of RNA samples over time. Methods:, For the PARSIFAL study, PBLC of 1155 children were collected using EDTA tubes in two countries. In the PASTURE study, tubes containing RNA-stabilizing solutions (PAXgene® Blood RNA Tubes; PreAnalytiX) were used to collect cord blood leucocytes of 982 children in five countries. Real-time PCR (conventional single tube assay and high-throughput low density arrays) was used to quantify expression of various innate immunity genes. In 77 PARSIFAL samples, gene expression was measured repeatedly during prolonged storage. Results:, In PARSIFAL (EDTA tubes) the median RNA yield after extraction significantly differed between the two centres (70 and 34 ng/,l). Collecting blood into an RNA-stabilizing solution markedly reduced differences in RNA yield in PASTURE (range of medians 91,107 ng/,l). The agreement [Spearman rank correlation (r)] between repeated measurements of gene expression decreased with increasing storage time [e.g., for CD14: r (first/second measurement) = 0.35; r (first/third measurement) = 0.03]. RNA levels measured with either the conventional method or low-density arrays were comparable (r > 0.9). Conclusion:, Collecting blood samples into tubes containing an RNA-stabilizing solution increases RNA yield and reduces its variability. Long-term storage of samples may lead to RNA degradation, requiring special attention in longitudinal studies. [source] Put Them Out to Pasture?HIPPOCAMPUS, Issue 10 2010Anyway, What Are Old Granule Cells Good for Abstract In this issue, Alme and colleagues propose a novel hypothesis that young adult-born neurons represent the functional population of the dentate gyrus, and that old granule cells "retire" from relevance. Here, we present several implications of this interesting theory for the function of both neurogenesis and the dentate gyrus. © 2010 Wiley-Liss, Inc. [source] Underground Vetch (Vicia sativa ssp. amphicarpa): A Potential Pasture and Forage Legume for Dry Areas in West AsiaJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 3 2003A. M. Abd El Moneim Abstract Subterranean vetch [Vicia sativa ssp. amphicarpa (Dorth.) Aschers & Graebn.] is native to disturbed grasslands of the Mediterranean basin where heavy grazing, seasonal drought and erosion act as strong selection forces. It produces two pod types, above-ground and 5 cm below the soil surface. Unlike subterranean clover (Trifolium subterranean L.), which buries its seeds after flowering above-ground, subterranean vetch flowers and forms pods beneath the soil surface on underground stems. The aerial pods are produced after vegetative development ceases, while the underground pods are produced in ontogeny. The ability of this unusual vetch to survive in marginal areas with low rainfall (about 250 mm year,1) and to produce nutritious herbage and pods is an important characteristic which helps address rehabilitation of degraded rangelands and increase feed production for small ruminants. Research at the International Center for Agricultural Research in the Dry Areas (ICARDA) during the 1988,93 growing seasons has assessed the herbage and seed productivity of underground vetch, its ability to grow in rotation with barley in marginal low-rainfall areas, and its capacity to regenerate after heavy grazing. Drier conditions in 1989 favoured earlier underground flowering; the number of underground pods was higher than that of aerial pods. Grain yield of barley (var. Atlas) was around 2.0 t ha,1 after underground vetch and only 1.2 t ha,1 after barley. Grazing underground vetch had no effect on the productivity of the succeeding barley crop. The aerial and underground pods serve two distinct functions; aerial pods increase dissemination within suitable habitats, while underground pods increase the probability of plant survival under adverse conditions such as drought and heavy grazing. Underground vetch has two potential uses, namely the rehabilitation of marginal areas and production in rotation with barley. [source] , -Carotene is incorporated or mobilized along with triglycerides in bovine adipose tissue in response to insulin or epinephrineJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1 2009E. Arias Summary Pasture fed cattle ingest substantial amounts of , -carotene (, -C). Not all of the carotenoid compound is transformed into vitamin A, but the surplus is deposited in adipose tissue (AT). The mechanisms of , -C incorporation and mobilization are unknown. Two experiments were conducted using explants from bovine AT cultured in vitro. First, , -C incorporation by explants from three animals was examined with different , -C concentrations (0, 1, 5 and 20 ,m) and different times of incubation (every 5 h up to 25 h). The data showed a significant increase of , -C concentration in explants only for 20 ,m, -C. Secondly, effects of insulin and epinephrine on , -C and triglyceride (TG) contents of explants were studied. Explants from six animals were incubated with either hormone and 0 or 20 ,m, -C for 20 h. Both TG and , -C contents were affected positively by insulin and negatively by epinephrine. Interestingly, changes in ratios of , -C/TG (hormone vs. control) were similar (1.7 × 10,3 and 1.8 × 10,3), respectively, for insulin and epinephrine, indicating that , -C level is directly related to TG content. We also report the presence of mRNA for , -C 15, 15, oxygenase in bovine AT. The in vitro culture system using explants from bovine AT is a promising model to investigate factors that might affect the accumulation and metabolism of , -C. [source] Pasture and Grain Finishing Affect the Color Stability of BeefJOURNAL OF FOOD SCIENCE, Issue 7 2002M.C. Lanari ABSTRACT: We determined the effect of pasture feeding (P0) or sorghum feeding with 2500 IU/head/d; (G2500) or without (G0) vitamin E supplementation on the color stability of gluteus medius (GM), longissimus lumborum (LL) and semimembranosus (SM). Diets did not affect the total pigment concentration of the muscle. Color stabilities were G2500 > P0 > G0 for fresh GM and SM and G2500 > G0 > P0 for fresh LL. Color stabilities of aged beef from the P0 and G2500 treatments were similar and higher than those from unsupplemented animals. Color stability of minced beef ranked as: P0 aged > G0 and G2500 fresh > P0 fresh > G0 and G2500 aged. [source] Small U.S. dairy farms: can they compete?AGRICULTURAL ECONOMICS, Issue 2009Richard Nehring Pasture-based system; Technical efficiency; Returns to scale; Dairy Abstract The U.S. dairy industry is undergoing rapid structural change, evolving from a structure including many small farmers in the Upper Midwest and Northeast to one that includes very large farms in new production regions. Small farms are struggling to retain competitiveness via improved management and low-input systems. Using data from USDA's Agricultural Resource Management Survey, we determine the extent of U.S. conventional and pasture-based milk production during 2003,2007, and estimate net returns, scale efficiency, and technical efficiency associated with the systems across different operation sizes. We compare the financial performance of small conventional and pasture-based producers with one another and with large-scale producers. A stochastic production frontier is used to analyze performance over the period for conventional and pasture technologies identified using a binomial logit model. Large conventional farms generally outperformed smaller farms using most economic measures,technical efficiency, various profitability measures, and returns to scale. [source] Association of Season and Pasture Grazing with Blood Hormone and Metabolite Concentrations in Horses with Presumed Pituitary Pars Intermedia DysfunctionJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 5 2010N. Frank Background: Pituitary pars intermedia dysfunction (PPID) is a risk factor for pasture-associated laminitis, which follows a seasonal pattern. Hypothesis: Hormonal responses to season differ between PPID and unaffected horses. Animals: Seventeen horses aged 8,30 years (14 horses , 20 years of age). Methods: Longitudinal observational study. Blood was collected monthly from August 2007 until July 2008 after pasture grazing and again after overnight stall confinement. Blood hormone and metabolite concentrations were measured and pasture grass samples were analyzed to determine carbohydrate content. Analysis of variance analysis for repeated measures was performed. Results: Mean ACTH concentrations varied significantly over time (P < .001), with higher concentrations detected in August, September, and October compared with November,April. Pasture × time effects were detected for glucose and insulin concentrations, with peaks observed in September. Horses were retrospectively allocated to PPID (n = 8) and control (n = 9) groups on the basis of plasma ACTH concentrations. Changes in insulin concentrations over time differed in the PPID group when compared with the control group. Insulin concentrations were positively correlated with grass carbohydrate composition. Conclusions and Clinical Importance: PPID did not affect the timing or duration of the seasonal increase in ACTH concentrations, but higher values were detected in affected horses. Insulin concentrations differed between groups, but hyperinsulinemia was rarely detected. Glucose and insulin concentrations peaked in September when horses were grazing on pasture, which could be relevant to the seasonal pattern of laminitis. [source] Productivity of Bahiagrass Pastures in South-western Japan: Synthesis of Data from Grazing TrialsJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2006M. Hirata Abstract This study examined the rate of herbage production and herbage quality of bahiagrass (Paspalum notatum Flügge) using data from five grazing trials in the low-altitude region of Kyushu, south-western Japan, in an effort to (a) evaluate productivity of bahiagrass pastures, (b) analyse its relationship to meteorological, vegetational and managerial variables, and (c) obtain implications for better management of bahiagrass pastures. The rate of herbage production, ranging from ,56 to 213 kg DM ha,1 day,1, tended to increase from spring (April,May) to mid-summer (July) and decrease thereafter. The rate was expressed by a multiple regression equation where nitrogen fertilizer rate, air temperature, rainfall and herbage mass had positive effects. Dry matter digestibility (DMD) and crude protein (CP) concentration of herbage were in the range of 471,727 and 84,161 g kg,1 DM respectively. DMD was expressed by a regression equation where the day number from 1 April and herbage mass had negative effects, and the sampling height and nitrogen rate had positive effects. CP concentration was expressed by an equation showing a positive effect of nitrogen rate and a negative effect of herbage mass. The results indicate that management of bahiagrass pastures should aim at maintaining herbage mass closely above the critical level below which intake by grazing animals is restricted, in order to increase quality and ensure quantity. This is particularly important when nitrogen fertilizer is applied. [source] Forest Regeneration in a Chronosequence of Tropical Abandoned Pastures: Implications for Restoration EcologyRESTORATION ECOLOGY, Issue 4 2000T. Mitchell Aide Abstract During the mid-1900s, most of the island of Puerto Rico was deforested, but a shift in the economy from agriculture to small industry beginning in the 1950s resulted in the abandonment of agricultural lands and recovery of secondary forest. This unique history provides an excellent opportunity to study secondary forest succession and suggest strategies for tropical forest restoration. To determine the pattern of secondary succession, we describe the woody vegetation in 71 abandoned pastures and forest sites in four regions of Puerto Rico. The density, basal area, aboveground biomass, and species richness of the secondary forest sites were similar to those of the old growth forest sites (>80 yr) after approximately 40 years. The dominant species that colonized recently abandoned pastures occurred over a broad elevational range and are widespread in the neotropics. The species richness of Puerto Rican secondary forests recovered rapidly, but the species composition was quite different in comparison with old growth forest sites, suggesting that enrichment planting will be necessary to restore the original composition. Exotic species were some of the most abundant species in the secondary forest, but their long-term impact depended on life history characteristics of each species. These data demonstrate that one restoration strategy for tropical forest in abandoned pastures is simply to protect the areas from fire, and allow natural regeneration to produce secondary forest. This strategy will be most effective if remnant forest (i.e., seed sources) still exist in the landscape and soils have not been highly degraded. Patterns of forest recovery also suggest strategies for accelerating natural recovery by planting a suite of generalist species that are common in recently abandoned pastures in Puerto Rico and throughout much of the neotropics. [source] Countryside Biogeography of Moths in a Fragmented Landscape: Biodiversity in Native and Agricultural HabitatsCONSERVATION BIOLOGY, Issue 2 2001Taylor H. Ricketts We sampled moth species richness within a 227-ha forest fragment and in four surrounding agricultural habitats (coffee, shade coffee, pasture, and mixed farms) in southern Costa Rica. We found no significant difference in moth species richness or abundance among agricultural habitats, but agricultural sites within 1 km of the forest fragment had significantly higher richness and abundance than sites farther than 3.5 km from the fragment. In addition, species composition differed significantly between distance classes ( but not among agricultural habitats), with near sites more similar to forest than far sites. These results suggest that (1) different agricultural production regimes in this region may offer similar habitat elements and thus may not differ substantially in their capacities to support native moth populations and (2) that the majority of moths may utilize both native and agricultural habitats and move frequently between them, forming "halos" of relatively high species richness and abundance around forest fragments. Correlations between species richness and the amount of nearby forest cover, measured over circles of various radii around the sites, suggest that halos extend approximately 1.0,1.4 km from the forest edge. The extent of these halos likely differs among taxa and may influence their ability to survive in fragmented landscapes. Resumen: Los estudios de paisajes fragmentados, especialmente en los trópicos, tradicionalmente se han enfocado en los fragmentos nativos per se, ignorando las distribuciones de especies en áreas agrícolas circundantes o en otras áreas dominadas por humanos. Muestreamos la riqueza de polillas dentro de un fragmento de bosque de 227 hectáreas y en cuatro hábitats agrícolas (café, café con sombra, pastizal y campos mixtos) en el Sur de Costa Rica. Encontramos que no hubo diferencias significativas en la riqueza de especies o en la abundancia de polillas entre los hábitats agrícolas, sin embargo, los sitios agrícolas cercanos (<1 km) al fragmento de bosque tuvieron una riqueza de especies y abundancia significativamente mayor que las de los sitios lejanos (>3.5 km) al fragmento. Además, la composición de especies fue significativamente diferente entre las clases de distancia ( pero no entre los hábitats agrícolas), siendo los sitios cercanos más similares al bosque que los sitios retirados. Estos resultados sugieren que (1) los diferentes regímenes de producción agrícola en esta región pueden ofrecer elementos de hábitat similares y por lo tanto pueden no diferir substancialmente en lo que se refiere a su capacidad para sostener poblaciones de polillas nativas y (2) que la mayoría de las polillas pueden utilizar tanto hábitatsnativos como agrícolas y mover frecuentemente entre ellos, formando "halos" con una riqueza de especies y una abundancia relativamente altas alrededor de los fragmentos del bosque. Las correlaciones entre la riqueza de especies y la cantidad de cobertura forestal circundante, medida en círculos de diferente radio alrededor de los sitios de estudio, sugiere que los halos se extienden aproximadamente 1.0,1.4 km del borde del bosque. La extension de estos halos posiblemente difiere entre taxones y puede influenciar sus habilidades para sobrevivir en paisajes fragmentados. [source] Effects of Fragmentation of Araucarian Vine Forest on Small Mammal CommunitiesCONSERVATION BIOLOGY, Issue 4 2000Jocelyn M. Bentley We examined the abundance of small mammal species in forests, corridors, remnants of araucarian vine forest, and Araucaria cunninghamii plantations and pastures. None of the forest mammal species persisted following conversion of forest to pasture. Plantations supported lowered abundances of a subset of forest species that were mainly habitat generalists with respect to their occurrence in different floristic types of undisturbed native forest. Within plantations, an increased subcanopy cover was associated with a more forest-like small mammal assemblage. Species' responses to habitat fragmentation varied. The floristic habitat generalists were largely tolerant of habitat fragmentation, their abundance being similar in forests, corridors, and remnants, and were capable of persisting in remnants a few hectares in area. Floristic habitat specialists were vulnerable to habitat fragmentation and thus were abundant in continuous forest, were less abundant in corridors, and were generally absent from remnants. Species that avoid the corridor matrix and are therefore constrained to the corridor may be disadvantaged by the linearity of the habitat, consistent with the predictions of central-place foraging theory. Although small remnants and corridors provide habitat for some species, those that are more specialized in their use of undisturbed habitat types require the retention or reestablishment of large intact areas. Resumen: La pérdida de hábitat y la fragmentación son amenazas importantes para la sobrevivencia de la fauna que depende del bosque. Examinamos la abundancia de especies de mamíferos pequeños en bosques, corredores, y en remanentes de bosques de vid araucarios y en plantaciones de Araucaria cunninghamii y pastizales. Ninguna de las especies de mamíferos del bosque persistió después de la conversión del bosque a pastizal. Las plantaciones favorecieron abundancias menores de un conjunto de especies del bosque integrado principalmente por generalistas de hábitat con respecto a su presencia en diferentes tipos florísticos de bosque nativo sin perturbar. Dentro de las plantaciones, cuanto mayor era la cobertura por debajo del dosel más se parecía el ensamblaje de mamíferos pequeños al del bosque. Las respuestas de las especies a la fragmentación del hábitat fueron variadas. Los generalistas del hábitat florístico por lo general toleraban la fragmentación del hábitat ( la abundancia en bosques, corredores y remanentes era similar) y fueron capaces de persistir en remanentes de unas pocas hectáreas de extensión. Los especialistas de hábitat florístico fueron vulnerables a la fragmentación del hábitat y por ello fueron más abundantes en bosques continuos, menos abundantes en corredores y generalmente ausentes en los remanentes. Las especies que evitaron la matriz de corredores y por lo tanto se encuentran limitadas al corredor pueden estar en desventaja por la linearidad del hábitat, consistente con las predicciones de la teoría del forrajeo de sitio central. A pesar de que los remanentes pequeños y los corredores proveen hábitat para algunas especies, aquéllas que son más especializadas en el uso de tipos de hábitat sin perturbar requieren de la retención o del restablecimiento de áreas intactas grandes. [source] The spatial distribution of badgers, setts and latrines: the risk for intra-specific and badger-livestock disease transmissionECOGRAPHY, Issue 4 2008Monika Böhm The spatial distribution of wildlife hosts and the associated environmental distribution of their excretory products are important factors associated with the risk of disease transmission between wildlife and livestock. At a landscape scale, heterogeneous distribution of a wildlife host will create regional hot spots for disease risk, while at the farm level, distributional patterns of wildlife excretory products as well as habitat use are of primary importance to the assessment of disease risk to livestock. In the UK, badgers have been implicated in the transmission of bovine tuberculosis to cattle. In this study, we focus on the spatial and social organization and habitat use of badgers as well as the distributions of their excretions at latrine and sett sites to assess intra- and inter-species (badger,cattle) disease risk. Across the study site, badger latrines and setts were found in prominent clusters, at distances of up to 250 and 200 m respectively. This was partly due to small-scale clustering of latrines around sett sites, so that disease risk may be higher within the vicinity of setts. The clustered distribution suggests that sites of high risk for TB transmission may be localised within farms. Exclusion of cattle from the few sett and latrine sites within their grazing pasture is therefore likely to provide an effective way of reducing the risk of disease transmission. We also found evidence of social sub-division within badger social groups based on differences in the use of main and outlier setts. This may contribute to localised clusters of infection within the badger population, resulting in heterogeneous patterns of environmental disease risk to the wider host community. A greater understanding of variation in host behaviour and its implications for patterns of disease will allow the development of more targeted and effective management strategies for wildlife disease in group-living hosts. [source] Plant species richness and environmental heterogeneity in a mountain landscape: effects of variability and spatial configurationECOGRAPHY, Issue 4 2006Alexia Dufour The loss of biodiversity has become a matter of urgent concern and a better understanding of local drivers is crucial for conservation. Although environmental heterogeneity is recognized as an important determinant of biodiversity, this has rarely been tested using field data at management scale. We propose and provide evidence for the simple hypothesis that local species diversity is related to spatial environmental heterogeneity. Species partition the environment into habitats. Biodiversity is therefore expected to be influenced by two aspects of spatial heterogeneity: 1) the variability of environmental conditions, which will affect the number of types of habitat, and 2) the spatial configuration of habitats, which will affect the rates of ecological processes, such as dispersal or competition. Earlier, simulation experiments predicted that both aspects of heterogeneity will influence plant species richness at a particular site. For the first time, these predictions were tested for plant communities using field data, which we collected in a wooded pasture in the Swiss Jura mountains using a four-level hierarchical sampling design. Richness generally increased with increasing environmental variability and "roughness" (i.e. decreasing spatial aggregation). Effects occurred at all scales, but the nature of the effect changed with scale, suggesting a change in the underlying mechanisms, which will need to be taken into account if scaling up to larger landscapes. Although we found significant effects of environmental heterogeneity, other factors such as history could also be important determinants. If a relationship between environmental heterogeneity and species richness can be shown to be general, recently available high-resolution environmental data can be used to complement the assessment of patterns of local richness and improve the prediction of the effects of land use change based on mean site conditions or land use history. [source] Starling foraging success in relation to agricultural land-useECOGRAPHY, Issue 3 2002Ola Olsson Changes in agricultural land-use have been suggested to contribute to the decline of several bird species through negative effects on their food supply during breeding. One important change in land-use has been loss of pastures, especially permanent pastures. In this study we investigated how different forms of agricultural land-use affected foraging success of a declining bird species, the European starling Sturnus vulgaris. We let caged starlings forage in different forms of agricultural fields and determined time spent foraging and foraging success. The starlings' activity level (time spent actively foraging) as well as the number of prey caught per time unit was strongly related to the abundance of prey in soil samples. Also the body mass change during the experiment was positively related to activity level and prey capture rate. We found consistent differences in foraging variables between habitats. In spring sown grain starlings were least active and found fewer prey items at a lower rate than in any other habitat. The other three habitats differed less, but in general mowed hay fields appeared slightly more valuable than the cultivated and natural pastures. We did not find any differences between natural and cultivated pastures in foraging variables. Thus, starling foraging success is higher in grass-covered fields than in cultivated fields, but the management of the grass-covered fields mattered less. The results are consistent with starlings having higher population densities and breeding success in areas with higher availability of pasture. We suggest that the physical structure of the habitat (sward height) and moisture may be additional variables that need to be taken into account to explain starling breeding density and success in the agricultural landscape. [source] Small-scaled geographical variation in life-history traits of the blowfly Calliphora vicina between rural and urban populationsENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 3 2009C. C. Hwang Abstract The impact of the urban heat-island effect, the warming-up of an urban area caused by human activity, on the blowfly Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) was examined at two British sites, 30 km apart. Waterloo in Central London is a highly urbanised built-up area, whereas Box Hill in the county of Surrey is a rural pasture and woodland location. The phenotypic plasticity of 12 C. vicina cultures, originated from single females from each of the two sites, was measured using three developmental characters: adult body size (represented as the length of the cross vein dm-cu of the right wing), development time as accumulated degree-days (ADD), and growth rate (length of dm-cu/ADD), along a constant temperature series of 16, 20, 24, and 28 °C in the laboratory. The blowflies from Box Hill had the same ADD as those from Waterloo, but showed a significantly larger adult size and growth rate at lower temperatures, suggesting the existence of local adaptations that may be caused by the differing levels of urbanisation between the two studied sites. Not surprisingly, a trade-off between adult size and development time was found. Females showed longer development times than males at all four temperatures, indicating they may need to ingest more food as larvae to furnish ovarioles and increase fecundity. However, females had larger adult size than males at 16 and 20 °C but a reverse at 28 °C, suggesting that females may be more cold-adapted than males. [source] Population dynamics of insects associated with Rumex obtusifolius in different habitatsENTOMOLOGICAL RESEARCH, Issue 2 2006Ohseok KWON Abstract The effect of different habitats on insect communities associated with Rumex obtusifolius was studied in detail. Study sites were selected for their variety of environmental characteristics (vegetation and habitat): shaded woodland, disturbed wasteland and pasture. The results of this study were that insect populations associated with R. obtusifolius responded differently to the different habitats. The observed differences in population dynamics among the insects showed quite clearly their responses to different habitats. There was also a pattern of time partitioning in the exploitation of the host-plant among the insect species observed. Philaenus spumarius at nymphal stage had a peak density on approximately 20 June, Apion frumentarium and Apion spp. (Apion species other than A. frumentarium) had a peak density on approximately 30 June and Aphis rumicis had a peak density on approximately 28 July. This pattern of shift in time for peak population density (time-shift) among the insects sharing a common host-plant may guarantee each insect the opportunity to exploit the plant to a maximum. [source] Disclosing arbuscular mycorrhizal fungal biodiversity in soil through a land-use gradient using a pyrosequencing approachENVIRONMENTAL MICROBIOLOGY, Issue 8 2010Erica Lumini Summary The biodiversity of arbuscular mycorrhizal fungi (AMF) communities present in five Sardinian soils (Italy) subjected to different land-use (tilled vineyard, covered vineyard, pasture, managed meadow and cork-oak formation) was analysed using a pyrosequencing-based approach for the first time. Two regions of the 18S ribosomal RNA gene were considered as molecular target. The pyrosequencing produced a total of 10924 sequences: 6799 from the first and 4125 from the second target region. Among these sequences, 3189 and 1003 were selected to generate operational taxonomic units (OTUs) and to evaluate the AMF community richness and similarity: 117 (37 of which were singletons) and 28 (nine of which were singletons) unique AMF OTUs were detected respectively. Within the Glomeromycota OTUs, those belonging to the Glomerales order were dominant in all the soils. Diversisporales OTUs were always detected, even though less frequently, while Archaeosporales and Paraglomerales OTUs were exclusive of the pasture soil. Eleven OTUs were shared by all the soils, but each of the five AMF communities showed particular features, suggesting a meaningful dissimilarity among the Glomeromycota populations. The environments with low inputs (pasture and covered vineyard) showed a higher AMF biodiversity than those subjected to human input (managed meadow and tilled vineyard). A reduction in AMF was found in the cork-oak formation because other mycorrhizal fungal species, more likely associated to trees and shrubs, were detected. These findings reinforce the view that AMF biodiversity is influenced by both human input and ecological traits, illustrating a gradient of AMF communities which mirror the land-use gradient. The high number of sequences obtained by the pyrosequencing strategy has provided detailed information on the soil AMF assemblages, thus offering a source of light to shine on this crucial soil microbial group. [source] The impact of grassland management on archaeal community structure in upland pasture rhizosphere soilENVIRONMENTAL MICROBIOLOGY, Issue 3 2003Graeme W. Nicol Summary The community structure of rhizosphere soil Archaea from three grassland types, associated with different management practices, was examined at a site in the Borders region of Scotland, by analysis of 16S rRNA gene fragments amplified from 16S rDNA and from rRNA. Denaturing gradient gel electrophoresis (DGGE) and sequence analysis of amplified products indicated high relative abundance within the archaeal community of two distinct lineages of non-thermophilic (group 1) Crenarchaeota. Grassland management practices influenced archaeal community structure, as characterized by both 16S rRNA- and 16S rDNA-derived DGGE profiles. One band dominated DGGE profiles in all three grassland types examined, and reproducible differences in the presence and intensity of bands were observed between profiles from managed and natural grassland sites. Analysis of 16S rRNA-derived amplicons from managed and natural grasslands at sites in the north of England and the north of Wales also indicated high relative abundance of non-thermophilic crenarchaeotes within the archaeal community. The band dominating the Scottish grassland site also dominated DGGE profiles from the English and Welsh sites, and similar differences were seen between profiles derived from soils subjected to different management regimes. The study indicates that grassland archaeal communities are dominated by Crenarchaeota, with closely related members of this lineage ubiquitous in distribution in UK upland pasture, and indicate that management practices influence the nature of the crenarchaeotal community. [source] Sublethal responses of wolf spiders (Lycosidae) to organophosphorous insecticidesENVIRONMENTAL TOXICOLOGY, Issue 5 2002S. Van Erp Abstract The activities of cholinesterase (ChE) and glutathione S -transferase (GST) enzymes were assessed in the wolf spider (Lycosa hilaris) as biomarkers of organophosphate contamination in agricultural ecosystems. Spiders were exposed to simulated field rates of two commercially available organophosphorous insecticides [Basudin (diazinon) and Lorsban (chlorpyrifos)] under laboratory conditions. In terms of survival, chlorpyrifos and diazinon were more toxic to male than to female wolf spiders, but gender-specific differences in ChE activities were not evident. Cholinesterase activity in male spiders was inhibited to 14% and 61% of control activity by Basudin and Lorsban, respectively. Gluthathione S -transferase activity was not affected by either pesticide. Mortality and biomarker responses in the wolf spider were further investigated following the application of Basudin to pasture. Wolf spiders were deployed into field mesocosms; after 24 h mortality was 40%, and surviving spiders displayed significant inhibition of ChE activity (87%) compared with controls. Cholinesterase activity in spiders exposed for subsequent 24- or 48-h time periods was monitored until it returned to control levels 8 days post-application. Inhibition of ChE activity after a single application of Basudin indicate the potential use of this enzyme in wolf spiders as a biomarker for evaluating organophosphate contamination. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 449,456, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10078 [source] Stringhalt associated with a pasture infested with Hypochoeris radicataEQUINE VETERINARY EDUCATION, Issue 3 2005S. Y. Gardner First page of article [source] Prediction of incipient pasture-associated laminitis from hyperinsulinaemia, hyperleptinaemia and generalised and localised obesity in a cohort of poniesEQUINE VETERINARY JOURNAL, Issue 2 2009R. A. CARTER Summary Reasons for performing study: The ability to predict ponies at increased risk of laminitic episodes, when exposed to nutrient dense pasture, would facilitate management to avoid disease. Objectives: To identify variables and clinically useful cut-off values with reproducible diagnostic accuracy for the prediction of ponies that subsequently developed laminitis when exposed to nutrient dense pasture. Methods: A cohort of predominantly Welsh and Dartmoor ponies from a closed herd was evaluated in March 2006 (n = 74) and March 2007 (n = 57). Ponies were categorised as never laminitic or previously laminitic according to reported laminitic history and as clinically laminitic (CL) if laminitis was observed within 3 months following evaluation. Body condition score (BCS), cresty neck score (CNS), girth and neck circumferences (NC), withers height, blood pressure and hoof surface temperature, and plasma insulin, glucose, triglyceride, leptin, cortisol, ACTH, uric acid and TNF-, concentrations were measured. Analysis of sensitivity, specificity and receiver operating characteristic curves was used to evaluate the diagnostic accuracy for a variable to predict CL ponies. Results: Variables with diagnostic accuracy for the prediction of CL ponies included insulin, leptin, BCS, CNS, and NC:height ratio. Specific cut-off values of insulin (>32 mu/l), leptin (>7.3 ng/ml), BCS (,7), CNS (,4) and NC:height ratio (>0.71) had reproducible diagnostic accuracy for the prediction of laminitis. Combining tests did not result in higher diagnostic accuracy than individual tests of insulin or leptin during either evaluation. Conclusions: Tests of insulin and leptin concentrations and measures of generalised (BCS) and localised (CNS or NC:height ratio) obesity were beneficial in the prediction of laminitic episodes. Potential relevance: These results highlight the importance of monitoring and reducing insulin concentration, and generalised and regional obesity in ponies to reduce risk of laminitis. [source] Airway inflammation in Michigan pleasure horses: prevalence and risk factorsEQUINE VETERINARY JOURNAL, Issue 4 2006N. E. Robinson Summary Reasons for performing study: Although subclinical airway inflammation is thought to be common in horses, there is little information on its prevalence and none on risk factors. Objective: To determine the prevalence and risk factors for an increased number of inflammatory cells and for mucus accumulation in the trachea of pleasure horses. Methods: Horses (n = 266) in stables (n = 21) in Michigan were examined endoscopically, once in winter and once in summer 2004. Visible tracheal mucoid secretions were graded 0,5 and inflammatory cell numbers counted in a tracheal lavage sample. Information collected about each horse included age, gender, presence of cough, percent time indoors and source of roughage. The repeated measures were analysed by generalised estimating equations and linear mixed models. Results: Horses eating hay, especially from round bales, had the most neutrophils, whereas horses feeding from pasture had the fewest. Being female and being outdoors in winter were associated with increased numbers of inflammatory cells. Older horses had fewer macrophages than young horses. More than 70% of horses had >20% neutrophils in tracheal lavage. Twenty percent of horses had a mucus accumulation score >1; 17% had both a mucus score >1 and >20% neutrophils. The significant risk factors for mucus accumulation >1 were age >15 years, feeding on hay as compared to pasture, and being outdoors for more than 80% time in winter. Even though mucus accumulation score >1 was a risk factor for cough, only half of such horses coughed. Cough and mucus accumulation were associated with increased number of neutrophils. Conclusions: In comparison to pasture feeding, hay feeding, particularly from round bales, was associated with an increased number of neutrophils in the airway. Being outdoors in winter was associated with increased numbers of inflammatory cells and with mucus accumulation. Because 70% of horses have >20% neutrophils, this value should not be used as the sole indicator of airway inflammation. Potential relevance: The study reinforces the importance of hay feeding and older age as risk factors for inflammatory airway disease. Horses that do not have ,heaves' may be best kept indoors when winters are cold. [source] Lysosomal storage disease in Sida carpinifolia toxicosis: an induced mannosidosis in horsesEQUINE VETERINARY JOURNAL, Issue 5 2003A. P. LORETTI Summary Reasons for performing study: This study reports a neurological disease unrecognised until now in ponies in southern Brazil. Hypothesis: Epidemiological data strongly suggests that the ingestion of Sida carpinifolia is involved in the aetiology. We tested the hypothesis that it is an acquired lyosomal storage disease. Methods: Following the death of 3 ponies, all ponies from the premises were closely monitored; epidemiological data and clinical findings carefully recorded. Fragments of several organs, including CNS, were fixed in neutral formalin and embedded in paraffin-wax. Sections were stained with haematoxylin and eosin. Representative sections of the cerebellum and trigeminal ganglia were submitted to lectin histochemical procedures. Results: The neurological disorder, characterised by stiff gait, muscle tremors, abdominal pain and death, was observed on a farm with 3 hectares of pasture. Three of 11 ponies died 15,20 days after they had been introduced into a new paddock heavily infested by the plant Sida carpinifolia. No significant gross lesions were observed. The main histological findings included multiple cytoplasmatic vacuoles in swollen neurones in the brain, cerebellum, spinal cord, autonomic ganglia (trigeminal and celiac ganglia), and submucosal and myenteric plexus of the intestines. In the kidneys, there was marked vacuolation of the proximal convoluted tubular cells. Sections of cerebellum and trigeminal ganglion were submitted to lectin histochemistry. The vacuoles in different cerebellar and ganglion cells reacted strongly to the following lectins: Concanavalia ensiformis, Triticum vulgaris and succinylated- Triticum vulgaris. Conclusions: The pattern of staining coincides with that of both swainsonine toxicosis and inherited mannosidosis reports. The histopathological changes were similar to those described in S. carpinifolia spontaneous and experimental poisoning in goats. This disease seems to be similar to Swainsona, Oxytropis and Astragalus toxicosis. Potential relevance: S. carpinifolia should be evaluated as a possible cause in the diagnosis of equine neuropathies. [source] Environment and prednisone interactions in the treatment of recurrent airway obstruction (heaves)EQUINE VETERINARY JOURNAL, Issue 5 2000C. A. Jackson Summary Recurrent airway obstruction (RAO) or heaves is a manifestation of a hypersensitivity to dust, moulds, and spores in the environment of a susceptible horse. Although in the majority of RAO-affected horses, clinical remission can be achieved by keeping horses at pasture to reduce their allergen exposure, this often is not practicable. For this reason, we investigated if changing the environment of a single stall in a 4 stall stable was sufficient to improve lung function and reduce inflammation in RAO-affected horses. In addition, we determined if addition of oral prednisone provided additional benefit. Twelve RAO-susceptible horses were stabled, fed hay, and bedded on straw until they developed airway obstruction. At this point, bedding was changed to wood shavings and they were fed a pelleted diet for 2 weeks. Lung function was measured and bronchoalveolar lavage was performed before and 3, 7, and 14 days after environmental modification. In a crossover design, horses were treated for the 14 days with prednisone tablets (2.2 mg/kg bwt, q. 24 h). Horses then returned to pasture for 30 days. Airway obstruction was greatest before environmental modification. Significant improvement in lung function occurred within 3 days of the change in environment and continued to Day 7. Airway function was best after 30 days at pasture. The clinical response achieved by environmental modification was not significantly improved by addition of oral prednisone. The total number of cells, total neutrophils, and percent neutrophils was greatest before environmental modification. In the absence of prednisone, total and percent neutrophils did not decrease until Day 14 and total cell number until 30 days at pasture. In the presence of prednisone, total cells and total and percent neutrophils decreased by Day 3 and again at pasture. The fact that lung function can be improved within 3 days by environmental management alone emphasises the need for allergen reduction as the cornerstone of treatment of RAO. Although prednisone induced a more rapid reduction in airway inflammation, this was not associated with a more rapid improvement in airway function. [source] Selective Defecation and Selective Foraging: Antiparasite Behavior in Wild Ungulates?ETHOLOGY, Issue 11 2004Vanessa O. Ezenwa Selective defecation and selective foraging are two potential antiparasite behaviors used by grazing ungulates to reduce infection by fecal,oral transmitted parasites. While there is some evidence that domestic species use these strategies, less is known about the occurrence and efficacy of these behaviors in wild ungulates. In this study, I examined whether wild antelope use selective defecation and selective foraging strategies to reduce exposure to gastrointestinal nematode parasites. By quantifying parasite levels in the environment in relation to the defecation patterns of three species, dik-dik (Madoqua kirkii), Grant's gazelle (Gazella granti), and impala (Aepyceros melampus), I found that nematode larval concentrations in pasture were higher in the vicinity of clusters of feces (dung middens) compared to single fecal pellet groups or dung-free areas. In addition, experimental feeding trials in free-ranging dik-dik showed that individuals selectively avoided feeding near concentrations of feces. Given that increased parasite contamination was found in the immediate vicinity of fecal clusters, fecal avoidance could help reduce host consumption of parasites and may therefore be an effective antiparasite behavior for certain species. On the other hand, while the concentration of parasite larvae in the vicinity of middens coupled with host avoidance of these areas during grazing could reduce host contact with parasites, results showing a positive correlation between the number of middens in a habitat and larval abundance at control sites suggest that dung middens might increase and not decrease overall host exposure to parasites. If this is the case, dung midden formation may not be a viable antiparasite strategy. [source] Predicting pasture root density from soil spectral reflectance: field measurementEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2010B. H. KUSUMO This paper reports the development and evaluation of a field technique for in situ measurement of root density using a portable spectroradiometer. The technique was evaluated at two sites in permanent pasture on contrasting soils (an Allophanic and a Fluvial Recent soil) in the Manawatu region, New Zealand. Using a modified soil probe, reflectance spectra (350,2500 nm) were acquired from horizontal surfaces at three depths (15, 30 and 60 mm) of an 80-mm diameter soil core, totalling 108 samples for both soils. After scanning, 3-mm soil slices were taken at each depth for root density measurement and soil carbon (C) and nitrogen (N) analysis. The two soils exhibited a wide range of root densities from 1.53 to 37.03 mg dry root g,1 soil. The average root density in the Fluvial soil (13.21 mg g,1) was twice that in the Allophanic soil (6.88 mg g,1). Calibration models, developed using partial least squares regression (PLSR) of the first derivative spectra and reference data, were able to predict root density on unknown samples using a leave-one-out cross-validation procedure. The root density predictions were more accurate when the samples from the two soil types were separated (rather than grouped) to give sub-populations (n = 54) of spectral data with more similar attributes. A better prediction of root density was achieved in the Allophanic soil (r2 = 0.83, ratio prediction to deviation (RPD ) = 2.44, root mean square error of cross-validation (RMSECV ) = 1.96 mg g ,1) than in the Fluvial soil (r2 = 0.75, RPD = 1.98, RMSECV = 5.11 mg g ,1). It is concluded that pasture root density can be predicted from soil reflectance spectra acquired from field soil cores. Improved PLSR models for predicting field root density can be produced by selecting calibration data from field data sources with similar spectral attributes to the validation set. Root density and soil C content can be predicted independently, which could be particularly useful in studies examining potential rates of soil organic matter change. [source] Enhancing the P trapping of pasture filter strips: successes and pitfalls in the use of water supply residue and polyacrylamideEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2008M. R. Redding Summary In intensive pastoral systems the landscape at ground level is clad in dense, filtering vegetation , yet phosphorus losses in overland flow do occur, and pollution of surface waters is a serious consequence. The use of pre-applied polyacrylamide (PAM) or chitosan to trap particulate phosphorus (PP) and P-sorbing potable water treatment alum residue (PWTR) to enhance vegetative filtering effects is examined here using field and laboratory overland flow simulation (flows from 0.43 to 0.34 litres s,1 (m width),1) and analysis. Fitted equations suggest that up to 40% of dissolved reactive P applied (0.75 mg P litre,1) in overland flow could be captured in a flow length of 2.1 m (1 kg PWTR m,2). Unfortunately, drying decreased PWTR effectiveness, though little of the P captured was readily desorbed. This effect did not appear to be the result of gibbsite formation. Compared with the other treatments, there was a strong treatment effect of pre-applied PAM on the change in PP losses (P < 0.001) over time, though evidence suggests the PAM effect declined during a 44 minute flow period. We showed that the investigated two-pronged approach to the enhancement of the effectiveness of P trapping by pasture had limitations. Laboratory sheet-flow simulations suggest that a field-stable P sorber with sorption characteristics similar to those of the un-dried PWTR could be an effective retention enhancer for dissolved P. Pre-applied PAM can have an effect on particulate-P trapping but was rapidly dissolved and removed by flow. [source] Soil organic carbon in density fractions of tropical soils under forest , pasture , secondary forest land use changesEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2008S. Paul Summary Our knowledge of effects of land use changes and soil types on the storage and stability of different soil organic carbon (SOC) fractions in the tropics is limited. We analysed the effect of land use (natural forest, pasture, secondary forest) on SOC storage (depth 0,0.1 m) in density fractions of soils developed on marine Tertiary sediments and on volcanic ashes in the humid tropics of northwest Ecuador. The origin of organic carbon stored in free light (< 1.6 g cm,3) fractions, and in two light fractions (LF) occluded within aggregates of different stability, was determined by means of ,13C natural abundance. Light occluded organic matter was isolated in a first step after aggregate disruption by shaking aggregates with glass pearls (occluded I LF) and in a subsequent step by manual destruction of the most stable microaggregates that survived the first step (occluded II LF). SOC storage in LFs was greater in volcanic ash soils (7.6 ± 0.6 Mg C ha,1) than in sedimentary soils (4.3 ± 0.3 Mg C ha,1). The contribution of the LFs to SOC storage was greater in natural forest (19.2 ± 1.2%) and secondary forest (16.6 ± 1.0%) than in pasture soils (12.8 ± 1.0%), independent of soil parent material. The amount of SOC stored in the occluded I LF material increased with increasing silt + clay content (sedimentary soils, r = 0.73; volcanic ash soils, r = 0.58) and aggregation (sedimentary soils, r = 0.52; volcanic ash soils, r = 0.45). SOC associated with occluded I LF, had the smallest proportion of new, pasture-derived carbon, indicating the stabilizing effect of aggregation. Fast turnover of the occluded II LF material, which was separated from highly stable microaggregates, strongly suggested that this fraction is important in the initial process of aggregate formation. No pasture-derived carbon could be detected in any density fractions of volcanic ash soils under secondary forest, indicating fast turnover of these fractions in tropical volcanic ash soils. [source] Fate of airborne metal pollution in soils as related to agricultural management.EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 3 2007Summary The fate of airborne metal pollutants in soils is still relatively unknown. We studied the incorporation of such airborne metal pollution in two soils under long-term permanent pasture (PP) and conventional arable land (CA). Both soils were located at an almost equal distance from a former zinc smelter complex and developed under comparable pedogenetic conditions. Profiles of total concentrations of Zn, chosen as a mobile, and Pb as a little- or non-mobile element, were examined and compared with macro- and micromorphological soil characteristics (soil colour, biological activity). The two soils showed different profiles of total Zn and Pb concentrations, with a marked decrease of concentrations of both elements under the plough layer in CA, whereas the decrease was more progressive in PP. However, the stocks of Zn and Pb for the 1-m soil profiles of CA and PP were comparable. Correlation of Zn and Pb concentration at different depths with total Fe contents and comparison with estimated data for the local geochemical background (LGCB), suggests transport of Zn from the surface to depth in CA and PP, and Pb movement in PP. In CA, 53% of Zn and 92.5% of Pb stocks derived from airborne metal pollution were located at depths < 26 cm. In PP, only 40% of Zn and 82% of Pb, derived from airborne pollution, were found in the A11 and A12 horizons (< 26 cm), the remaining 18% of the Pb stock being incorporated until 50 cm depth; one-third of total Zn stock ascribed to airborne pollution was found at depths > 50 cm. Studies of the composition of gravitational water collected in soils from the same study area suggest two mechanisms for metal movement. First, mobile metal ions (Zn2+) move in the soil solution and are intercepted by iron-clay complexes in deeper soil horizons. Second, observed only in PP, simultaneous movement of Zn and Pb is ascribed to bioturbation by earthworms. [source] | ||||||||||||||||||||||||||||||||||||||||||||||