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1
Parker, EM, CP Gardiner, AE Kessell i AJ Parker. "Hypovitaminosis A in extensively grazed beef cattle". Australian Veterinary Journal 95, nr 3 (27.02.2017): 80–84. http://dx.doi.org/10.1111/avj.12560.
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Fogarty, Eloise S., David L. Swain, Greg M. Cronin, Luis E. Moraes i Mark Trotter. "Behaviour classification of extensively grazed sheep using machine learning". Computers and Electronics in Agriculture 169 (luty 2020): 105175. http://dx.doi.org/10.1016/j.compag.2019.105175.
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Wehn, Sølvi, Knut Anders Hovstad i Line Johansen. "The relationships between biodiversity and ecosystem services and the effects of grazing cessation in semi-natural grasslands". Web Ecology 18, nr 1 (13.04.2018): 55–65. http://dx.doi.org/10.5194/we-18-55-2018.
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Abstract. Land use change can affect biodiversity, and this has an impact on ecosystem services (ESs), but the relationships between biodiversity and ESs are complex and poorly understood. Biodiversity is declining due to the abandonment of extensively grazed semi-natural grasslands. We therefore aim to explore relationships between biodiversity and ESs provided by extensively managed semi-natural grasslands. Focusing on vascular plant species richness, as well as the ESs fodder quantity, quality, and stability, allergy control, climate regulation, nutrient cycling, pollination, and aesthetic appreciation, we carried out botanical field surveys of 28 paired extensively grazed and abandoned semi-natural grassland plots, with four subplots of 4 m2 in each plot. The management of the semi-natural grasslands is and has been at low intensity. We calculated the influence of abandonment on the ES indicators, measured the correlation between the biodiversity measure of vascular plant species richness and ES indicators, and finally determined how the relationships between plant species richness and the ES indicators were affected by the cessation of the extensive management. ES indicators are often, but not always, positively correlated with species richness. Cessation of extensive grazing has both negative and positive effects on ES indicators but the relationships between species richness and ES indicators are often different in extensively managed and abandoned semi-natural grasslands. The relationships between species richness and ES indicators are less pronounced in the extensively managed semi-natural grassland than for the abandoned. One possible reason for this outcome is high functional redundancy in the extensively managed semi-natural grasslands.
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Goosey, Hayes B., Patrick G. Hatfield, Sue L. Blodgett i S. Dennis Cash. "Evaluation of Alfalfa Weevil (Coleoptera: Curculionidae) Densities and Regrowth Characteristics of Alfalfa Grazed by Sheep in Winter and Spring". Journal of Entomological Science 39, nr 4 (1.10.2004): 598–610. http://dx.doi.org/10.18474/0749-8004-39.4.598.
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Fall regrowth of alfalfa, Medicago sativa (L.), serves as a major source of winter pasture for Montana sheep producers. In years of drought, alfalfa fields are extensively winter/spring grazed; however, the impact on crop health is unknown. Alfalfa paddocks were continuously grazed for 95 d in 2002 and 98 d in 2003 during winter and spring to determine the impact on spring and summer alfalfa regrowth, nutrient quality characteristics, and alfalfa weevil, Hypera postica Gyllenhal, densities. Grazed and non-grazed forage yield, crude protein (%), and acid and neutral detergent fibers (%) did not differ at harvest (P> 0.17) during either study year. Acid and neutral detergent fibers (kg/ha) were greater (P < 0.05) in non-grazed compared to grazed plots during 2002–2003. Alfalfa weevil densities were lower in grazed than non-grazed plots (P< 0.03) over four sampling dates during both study years. Winter/spring sheep grazing appears to offer potential for alfalfa weevil management without compromising yield or nutritive factors of subsequent alfalfa production.
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Liddell, Caroline, Eric R. Morgan, Katie Bull i Christos C. Ioannou. "Response to resources and parasites depends on health status in extensively grazed sheep". Proceedings of the Royal Society B: Biological Sciences 287, nr 1920 (5.02.2020): 20192905. http://dx.doi.org/10.1098/rspb.2019.2905.
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A fundamental question in animal ecology is how an individual's internal state and the external environment together shape species distributions across habitats. The increasing availability of biologgers is driving a revolution in answering this question in a wide range of species. In this study, the position of sheep ( Ovis aries ) from Global Positioning System collars was integrated with remote sensing data, field sampling of parasite distributions, and parasite load and health measures for each tagged individual. This allowed inter-individual variation in habitat use to be examined. Once controlling for a positive relationship between vegetation productivity and tick abundance, healthier individuals spent more of their time at sites with higher vegetation productivity, while less healthy individuals showed a stronger (negative) response to tick abundance. These trends are likely to represent a trade-off in foraging decisions that vary between individuals based on their health status. Given the rarity of studies that explore how animal distributions are affected by health and external factors, we demonstrate the value of integrating biologging technology with remote sensing data, traditional ecological sampling and individual measures of animal health. Our study, using extensively grazed sheep as a model system, opens new possibilities to study free-living grazing systems.
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Skiba, U., S. K. Jones, J. Drewer, C. Helfter, M. Anderson, K. Dinsmore, R. McKenzie, E. Nemitz i M. A. Sutton. "Comparison of soil greenhouse gas fluxes from extensive and intensive grazing in a temperate maritime climate". Biogeosciences Discussions 9, nr 8 (2.08.2012): 10057–85. http://dx.doi.org/10.5194/bgd-9-10057-2012.
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Abstract. Greenhouse gas (GHG) fluxes from a seminatural, extensively sheep grazed drained moorland and intensively sheep grazed fertilised grassland in SE Scotland were compared over 4 yr (2007–2010). Nitrous oxide and CH4 fluxes were measured by static chambers, respiration from soil including ground vegetation by a flow through chamber and the net ecosystem exchange of CO2 by eddy covariance. All GHG fluxes displayed high temporal and interannual variability. Temperature, radiation, water table height and precipitation could explain a significant percentage of seasonal and interannual variations. Greenhouse gas fluxes were dominated by the net ecosystem exchange of CO2, emissions of N2O from the grazed grassland (384 g CO2eq m−2 yr−1) and emissions of CH4 from ruminant fermentation (147 g CO2eq m−2 yr−1). Methane emissions from the moorland were small (6.7 g CO2eq m−2 yr−1). Net ecosystem exchange of CO2 and respiration were much larger on the productive fertilised grassland (−1624 and +7157 g CO2eq m−2 yr−1, respectively) than the seminatural moorland (−338 and +2554 g CO2eq m−2 yr−1, respectively). Large CH4 and N2O losses from the grazed grassland counteracted the CO2 uptake by 35%, whereas the small N2O and CH4 emissions from the moorland did only impact the NEE by 2%.The 4 yr average GHG budget for the grazed grassland was 1006 g CO2eq m−2 yr−1 and 331 g CO2eq m−2 yr−1 for the moorland.
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CZOBEL, Szilard, Orsolya SZIRMAI, Zoltan NEMETH, Csaba GYURICZA, Judit GAZI, Andrea TOTH, Judit SCHELLENBERGER, Laszlo VASA i Karoly PENKSZA. "Short-term Effects of Grazing Exclusion on Net Ecosystem CO2 Exchange and Net Primary Production in a Pannonian Sandy Grassland". Notulae Botanicae Horti Agrobotanici Cluj-Napoca 40, nr 2 (5.11.2012): 67. http://dx.doi.org/10.15835/nbha4028300.
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Using portable, non-destructive own developed chambers (d=60 cm) and infrared gas analyses, the in situ field investigation was performed to study the seasonal and inter-annual dynamics of the stand level CO2-flux and production of sandy grassland that has been extensively grazed for decades. Furthermore, NEE measurements and biomass samples were used to identify the initial effects of grazing exclusion on CO2 exchange, aboveground phytomass and potential plant productivity in years of significantly different precipitation levels. A considerable inter-annual variation in all of the studied parameters was found both in the non-grazed and grazed stands. As a result of the grazing exclusion the CO2 uptake potential of the non-grazed stand increased by 13% compared to the grazed stand. It was more significant in the extreme dry year (220%), however, in wet year slightly lower average carbon sequestration was detected at the non-grazed stand (-13%), than that of the grazed area. Significant carbon sequestration potential was only detected during wet periods in both stands. The rate of CO2 uptake was found to be nearly six times higher in the non-grazed stand in the wet year than in the previous extremely dry year. The drought in 2003 significantly reduced the CO2 uptake of both stands, leading to lower annual net primary production and potential plant productivity. The annual net primary production dropped by almost 40% in the extremely dry year but then it rose by nearly two and a half times in the subsequent year with adequate rainfall.
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Trevisan, Dominique, Jean Marcel Dorioz, Jérome Poulenard, Philippe Quetin, Claire Prigent Combaret i Philippe Merot. "Mapping of critical source areas for diffuse fecal bacterial pollution in extensively grazed watersheds". Water Research 44, nr 13 (lipiec 2010): 3847–60. http://dx.doi.org/10.1016/j.watres.2010.04.039.
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Hill, BD, RG Holroyd i M. Sullivan. "Clinical and pathological findings associated with congenital hypovitaminosis A in extensively grazed beef cattle". Australian Veterinary Journal 87, nr 3 (marzec 2009): 94–98. http://dx.doi.org/10.1111/j.1751-0813.2009.00398.x.
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Skiba, U., S. K. Jones, J. Drewer, C. Helfter, M. Anderson, K. Dinsmore, R. McKenzie, E. Nemitz i M. A. Sutton. "Comparison of soil greenhouse gas fluxes from extensive and intensive grazing in a temperate maritime climate". Biogeosciences 10, nr 2 (26.02.2013): 1231–41. http://dx.doi.org/10.5194/bg-10-1231-2013.
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Abstract. Greenhouse gas (GHG) fluxes from a seminatural, extensively sheep-grazed drained moorland and intensively sheep-grazed fertilised grassland in South East (SE) Scotland were compared over 4 yr (2007–2010). Nitrous oxide (N2O) and methane (CH4) fluxes were measured by static chambers, respiration from soil plus ground vegetation by a flow-through chamber, and the net ecosystem exchange (NEE) of carbon dioxide (CO2) by eddy-covariance. All GHG fluxes displayed high temporal and interannual variability. Temperature, radiation, water table height and precipitation could explain a significant percentage of seasonal and interannual variations. Greenhouse gas fluxes were dominated by the net ecosystem exchange of CO2 at both sites. Net ecosystem exchange of CO2 and respiration was much larger on the productive fertilised grassland (−1567 and 7157 g CO2eq m−2 yr−1, respectively) than on the seminatural moorland (−267 and 2554 g CO2eq m−2 yr−1, respectively). Large ruminant CH4 (147 g CO2eq m−2 yr−1) and soil N2O (384 g CO2eq m−2 yr−1) losses from the grazed grassland counteracted the CO2 uptake by 34%, whereas the small N2O (0.8 g CO2eq m−2 yr−1) and CH4 (7 g CO2eq m−2 yr−1) emissions from the moorland only impacted the NEE flux by 3%. The 4-yr average GHG budget for the grazed grassland was −1034 g CO2eq m−2 yr−1 and −260 g CO2eq m−2 yr−1 for the moorland.
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Barrett, David C. "Cattle Review". Livestock 25, nr 1 (2.01.2020): 23. http://dx.doi.org/10.12968/live.2020.25.1.23.
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Introduction: In this, the first Cattle Review of the new decade, we consider three open access papers on the likely effectiveness of the TB control and eradication programme in Ireland, BVDV transmission in extensively grazed beef cattle, and farmers' awareness of hypomagnesaemia in UK cattle and sheep and the measures taken to prevent and control the condition.
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Sárospataki, M., A. Báldi, P. Batáry, Z. Józan, S. Erdős i T. Rédei. "Factors affecting the structure of bee assemblages in extensively and intensively grazed grasslands in Hungary". Community Ecology 10, nr 2 (grudzień 2009): 182–88. http://dx.doi.org/10.1556/comec.10.2009.2.7.
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Balmer, Oliver, i Andreas Erhardt. "Consequences of Succession on Extensively Grazed Grasslands for Central European Butterfly Communities: Rethinking Conservation Practices". Conservation Biology 14, nr 3 (czerwiec 2000): 746–57. http://dx.doi.org/10.1046/j.1523-1739.2000.98612.x.
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James, P. J., B. J. Horton, N. J. Campbell, D. L. Evans, J. Winkleman i R. McPhie. "Population dynamics and production effects of sheep lice (Bovicola ovis Schrank) in extensively grazed flocks". Animal Production Science 51, nr 8 (2011): 753. http://dx.doi.org/10.1071/an11008.
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An experiment was conducted to characterise population dynamics of lice and associated production loss in extensively grazed flocks infested at different times after shearing. Merino wethers were allocated to six groups of 31 sheep. In the first year (Y1), one sheep in each of two groups was infested with 2500 lice at 6 weeks after shearing (September), sheep in two groups were infested at 4 months (December) and two groups remained uninfested. In year 2 (Y2), infestations carried over from Y1, but a lousy sheep was added to each 6-week infestation mob. In year 3 (Y3), the infested mobs were treated and remained lice free, while lousy donor sheep were added to the two previously uninfested mobs. In Y1, lice appeared to die out in one 6-week-infestation group and were found on only two sheep before next shearing in the other. Lice persisted and spread in the two 4-month-infestation flocks, reaching mean counts (±s.e.) of 0.5 (±0.2) and 0.2 (±0.1) per part before shearing. In Y2 and Y3, lice persisted and increased in all infested flocks, reaching mean counts of 2.3 (±0.6), 8.5 (±1.5), 3.6 (±0.6) and 2.8 (±0.7) per part in Y2 and 1.0 (±0.2) and 1.2 (±0.4) per part in Y3. The count of 8.5 was in the flock with both a carry-over infestation and an infestor sheep. Exponential and logistic models were fitted to describe lice increase; differences in fleece derangement reflected louse numbers. Clean fleece weight was higher in flocks without lice in all years (0.12 kg/head in Y1; 0.22 kg/head in Y2 and Y3; P < 0.05). Classer-assigned colour scores (although not measured colour), cott score and line into which the wool was classed also differed significantly (P < 0.05) between infested and non-infested flocks and there was an indication that staple length was reduced in more heavily infested flocks. In spring-shorn flocks in environments with high solar radiation and no lice present at shearing, even if lice subsequently enter the mob, it appears unlikely that they will increase to levels where serious economic loss will be experienced before next shearing. The study also indicated that lice could persist in flocks at levels unlikely to be detected by most commercial wool producers for extended periods, possibly through one season, which may help to explain reports of new infestations with no apparent source.
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Wezel, A. "Variation of soil and site parameters on extensively and intensively grazed hillslopes in semiarid Cuba". Geoderma 134, nr 1-2 (wrzesień 2006): 152–59. http://dx.doi.org/10.1016/j.geoderma.2005.10.001.
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Marsden, Karina A., Jon A. Holmberg, Davey L. Jones, Alice F. Charteris, Laura M. Cárdenas i David R. Chadwick. "Nitrification represents the bottle-neck of sheep urine patch N2O emissions from extensively grazed organic soils". Science of The Total Environment 695 (grudzień 2019): 133786. http://dx.doi.org/10.1016/j.scitotenv.2019.133786.
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Pittarello, Marco, Alessandra Gorlier, Giampiero Lombardi i Michele Lonati. "Plant species selection by sheep in semi-natural dry grasslands extensively grazed in the south-western Italian Alps". Rangeland Journal 39, nr 2 (2017): 123. http://dx.doi.org/10.1071/rj16068.
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Sheep can have an important role in the conservation of abandoned and shrub- and tree-encroached, semi-natural dry grasslands because their feeding behaviour is known to affect plant diversity and structure. Nevertheless, little information is available about feeding preferences of sheep at the sward-patch scale and about the effects of stocking density on their selectivity. Consequently, we investigated plant-species selection by sheep managed with a low-intensity grazing, examining the influence of stocking density and plant species abundance by means of vegetation surveys and animal GPS tracking. Sheep grazed a graminoid-dominated, semi-natural dry grassland (Festuco–Brometea) in Piedmont Region, north-west Italy. Plant species, classified into graminoids, suffruticose forbs, and herbaceous forbs, were selected with a different intensity by sheep, which preferred graminoids over suffruticose and herbaceous forbs. Plant species showing a high consumption ratio (CR), i.e. the level of selection of plant species (CR >10%), were mostly graminoids (e.g. Bromus erectus, Koeleria vallesiana and Stipa pennata). Furthermore, Carex species were also noticeably selected, in particular C. humilis, whereas spiny species and those with a rosette or prostrate forms were rarely grazed. The heterogeneity of stocking density over the pasture allowed testing of the relationships between stocking density and CR. For many species, the higher the stocking density, the higher was the CR, regardless of the abundance of dominant neighbouring species. Results suggest that sheep under low-intensity grazing conditions exert a specific plant-species selection in abandoned dry grasslands. By regulating the stocking density through the management of grazing sheep, it may be possible to condition the consumption of certain plant species, with medium–long-term effects on the botanical composition.
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Hunt, L. P. "Safe pasture utilisation rates as a grazing management tool in extensively grazed tropical savannas of northern Australia". Rangeland Journal 30, nr 3 (2008): 305. http://dx.doi.org/10.1071/rj07058.
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The concept of safe pasture utilisation rates is frequently promoted as a tool for use in setting livestock numbers in perennial grass pastures in northern Australia’s tropical savannas to achieve a grazing intensity that is ecologically and economically sustainable. However, recommended pasture utilisation rates have been defined and applied in several ways, and this has led to some confusion among managers, researchers and advisers about their appropriate use. In order to reduce this confusion, this paper reviews the ecological basis and use of safe pasture utilisation rates as a management tool, concentrating on two common ways (i.e. strategic and tactical) in which they are applied. The main objective of both approaches is to limit the intensity of grazing of perennial grasses during the growing season when they are most sensitive to defoliation. When used in a strategic way, safe pasture utilisation rates provide an indication of long-term safe stocking rates that will avoid pasture deterioration in most years. Alternatively, they are used in a tactical sense to adjust stocking rates to track forage production, usually on an annual basis. Using the tactical approach, stocking rates are set at the end of the growing season in order to use a ‘safe’ proportion of the standing forage available at that time during the subsequent 12 months. Thus, stocking rates for one growing season are based on the quantity of forage available at the end of the previous growing season. In areas with high year-to-year variability in pasture growth this may lead to overgrazing during the growing season. This paper concludes by suggesting several strategies to better manage pasture utilisation levels under a tactical management approach to ensure that palatable perennial grass populations persist in the long term. A call is also made for researchers and land management advisers to be clear in the way recommended safe pasture utilisation rates are defined and intended to be used.
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Tarmi, Sanna, i Terho Hyvönen. "Plant Species Diversity and Composition of Plant Communities in Buffer Zones with Variable Management Regimes". Sustainable Agriculture Research 1, nr 2 (17.07.2012): 152. http://dx.doi.org/10.5539/sar.v1n2p152.
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<p>Field boundaries with permanent vegetation cover are a key habitat for farmland biodiversity. Buffer zones are wide field boundaries established to prevent nutrient leaching and erosion into waterways and serve as habitats for farmland wildlife. Our main hypothesis was that several years of grazing or cutting management results in greater plant species richness and heterogeneity in buffer zones in comparison with sites managed for only a few years. We also hypothesized that litter cover and soil phosphorus (P) level would decrease after several years of management, in comparison sites with relatively few years of management. Through this study we aimed to gain a better understanding of how to increase biodiversity in buffer zones. The study included 15 buffer zones within a single landscape. Mean species richness was significantly higher in the group of sites grazed over several years (21 species) in contrast to extensively cut sites (14.8 species) and/or grazed sites (18 species). Species heterogeneity did not respond to different management regimes. Management, slope aspect and litter were significant explanatory factors for species composition. The amount of soil phosphorus measured at three different depths was significantly lower in the buffer zones managed by cutting or grazing for a few years in contrast to those that were grazed for several years. Management that positively affected species diversity did not result in the expected decrease in soil phosphorus. Therefore, we propose that the greater species richness at grazed sites results mainly from disturbances caused by grazing.</p>
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Callaghan, M. J., N. W. Tomkins, I. Benu i A. J. Parker. "How feasible is it to replace urea with nitrates to mitigate greenhouse gas emissions from extensively managed beef cattle?" Animal Production Science 54, nr 9 (2014): 1300. http://dx.doi.org/10.1071/an14270.
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Reducing methane emissions from cattle in Australia will be dependent upon finding a strategy that can be readily adopted by its northern beef industry. The majority of the herd are located in this region and they graze low-quality tropical (C4) pastures, resulting in high methane output. There are few mitigation options that can be readily applied to extensively grazed cattle. The addition of nitrate to the diet of cattle has been shown to reduce methane production and may be an applicable strategy in northern Australia. Nitrogen is often the primary limiting nutrient in low-quality tropical pastures and it is common practice by industry to supplement with urea. Supplying an equivalent dose of nitrogen using nitrate as an alternative to urea has been demonstrated in cattle without adverse impacts upon animal productivity or health. These findings may not be directly applicable to grazing cattle in northern Australian because the diets and feeding management are not representative of the region. Nitrite toxicity can result from feeding nitrates to livestock and there is evidence that the composition of the total diet and feeding pattern influences the risk of toxicity. If nitrate supplementation in grazing beef cattle in northern Australia can be demonstrated to reduce methane and be applied safely, adoption rates will still depend on carbon market pricing. Current modelling suggests that the cost of supplementing beef cows with nitrate in northern Australia would be at least double the cost of urea supplementation.
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NIKOLOV, STOYAN C. "Effects of land abandonment and changing habitat structure on avian assemblages in upland pastures of Bulgaria". Bird Conservation International 20, nr 2 (30.11.2009): 200–213. http://dx.doi.org/10.1017/s0959270909990244.
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SummaryOver the past half century, grassland birds in Europe have declined dramatically and in order to maintain and restore their populations it is critical to understand how habitat structures and quality within pastures affect birds. This study investigated the effects of habitat structure and pasture abandonment on grassland birds in IBA Ponor, western Bulgaria. Birds were sampled using the point count method at 143 randomly located circular plots and a total of 1,401 observations of birds from 31 species were recorded. The results showed that habitat complexity, management and landscape position influenced bird community structure and species occurrence within the upland pastures. Extensively grazed pastures supported higher structural complexity of vegetation cover and higher bird-species richness and diversity compared with abandoned ones. Moreover, bird species with a preference for grazed rather than abandoned pastures had higher conservation status and most were associated with shrub cover. To maintain high levels of avian diversity, habitat complexity within pastures should be maintained through extensive grazing, to ensure availability of scrub vegetation wherever possible. Finally, this study provided evidence that agri-environmental schemes should not be directly extrapolated from one country or region to another without been tested first, because within the same management, differences in habitat structural characteristics may exist due to the landscape and socio-economic characteristics of the region.
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BATÁRY, PÉTER, ANDRÁS BÁLDI i SAROLTA ERDŐS. "The effects of using different species conservation priority lists on the evaluation of habitat importance within Hungarian grasslands". Bird Conservation International 17, nr 1 (marzec 2007): 35–43. http://dx.doi.org/10.1017/s0959270906000591.
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Many bird species of conservation importance inhabit the grasslands of the Hungarian Great Plain. Although extensive grazing management usually supports more bird species than intensive management, the conservation priority is to protect rare or declining species. Therefore, the conservation status of species must also be included in assessments of the value of different habitats. We used territory mapping to count birds in 21 extensively and intensively grazed field pairs on the Hungarian Great Plain, and subsequently adjusted site scores depending on which species appeared on various lists of priority taxa. We investigated differences in conservation scores of two global conservation lists (the Bonn Convention and another based on values of eight biological characteristics), two West Europe based lists (Bird Directive and CORINE), three continental lists (European Threat Status, SPEC and Bern Convention) and two Hungarian lists (protected species of Hungary and an alternative based on the specifics of Hungarian populations). Extensively managed fields had higher conservation values under seven of the nine priority lists: only the two West Europe based lists showed opposite trends in more than half the study areas. Since both West Europe based lists cover many central and eastern European countries, there is an urgent need to revise these lists, especially the Bird Directive list that gives serious legal responsibilities to countries.
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Morton, J. F. "Pastoralist parliamentary groups: a comparative study". Proceedings of the British Society of Animal Science 2005 (2005): 24. http://dx.doi.org/10.1017/s1752756200009352.
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Pastoralists (broadly speaking, people dependent on extensively grazed livestock for their livelihoods), are a vulnerable group of people who have been marginalised in developmental and political terms, and whose problems are very different from those of people in mainstream agricultural areas. Pastoralist Parliamentary Groups (PPGs), groupings of MPs concerned with the issue of pastoralism, have been formed since 1997 in the national parliaments of Ethiopia, Kenya and Uganda (Mohammed Mussa 2004, Livingstone forthcoming a and b). A research project investigated the context, successes and failures of the three PPGs, using interviews with their members and other stakeholders and document review.
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Farruggia, A., B. Dumont, P. D’hour i D. Egal. "How does protein supplementation affect the selectivity and performance of Charolais cows on extensively grazed pastures in late autumn?" Grass and Forage Science 63, nr 3 (wrzesień 2008): 314–23. http://dx.doi.org/10.1111/j.1365-2494.2008.00644.x.
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MARRIOTT, C. A., G. T. BARTHRAM i G. R. BOLTON. "Seasonal dynamics of leaf extension and losses to senescence and herbivory in extensively managed sown ryegrass–white clover swards". Journal of Agricultural Science 132, nr 1 (luty 1999): 77–89. http://dx.doi.org/10.1017/s0021859698006121.
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Tissue flow measurements of leaf material in Lolium perenne (perennial ryegrass), Agrostis capillaris or Poa annua, and Trifolium repens (white clover) were made at three upland sites in Scotland (Hartwood, Sourhope and Fasque) in 1992/93 to determine if there were differences in seasonal growth, senescence and losses to herbivory between species in their response to more extensive sward management. The measurements were made monthly from May until October in established predominantly perennial ryegrass/white clover swards receiving three different treatments. One treatment received a conventional annual fertilizer application of 140 kg N/ha plus maintenance P and K and was grazed by sheep at a sward height of 4 cm (4F), whereas the other two treatments were unfertilized and grazed to maintain a sward height of 4 cm (4U) or 8 cm (8U).Significant sources of the variation in leaf appearance, increase in green lamina/petiole length (leaf extension), senescence and losses to herbivory were attributable to site, sward, species and date of measurement. The rate of leaf extension for all three measured species was less in 4U than 4F swards, and less in 4U than 8U swards. Leaf extension of L. perenne exceeded that of the other species, even in unfertilized swards, but rates of leaf appearance were less. There was some evidence in spring of a reduction in net growth as a consequence of removing fertilizer inputs and maintaining a sward height of 4 cm. Species differences in the losses of leaf tissue to herbivory were dependent on sward management. In the 4F treatment, leaf loss to herbivory from L. perenne tillers was greater than that from either A. capillaris, P. annua or T. repens in May, June and September. In the 4U treatment more leaf tissue was also lost from L. perenne than from T. repens. In contrast, there was no difference between grass species in losses to herbivory in either unfertilized sward. The responses of species to changes in fertilizer and grazing management were similar at three sites of differing fertility. The results are discussed in relation to plant competition and species dynamics in extensively managed swards.
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de Sosa, Laura L., Helen C. Glanville, Miles R. Marshall, A. Prysor Williams, Maïder Abadie, Ian M. Clark, Aimeric Blaud i Davey L. Jones. "Spatial zoning of microbial functions and plant-soil nitrogen dynamics across a riparian area in an extensively grazed livestock system". Soil Biology and Biochemistry 120 (maj 2018): 153–64. http://dx.doi.org/10.1016/j.soilbio.2018.02.004.
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Kaupuža, Renāte, i Gotfrīds Noviks. "DETERMINATION OF HABITAT 6270*_3 PERMITTED DRAINAGE RATE". HUMAN. ENVIRONMENT. TECHNOLOGIES. Proceedings of the Students International Scientific and Practical Conference, nr 23 (24.04.2019): 122. http://dx.doi.org/10.17770/het2019.23.4403.
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Amelioration has dramatically altered the distribution of semi-natural grasslands in Latvia and as a result of the drainage, and the ocurrance of humid grassland habitats has decreased sharply. The aim of the paper was to identify drainage rate for habitat 6270*_3 ecohydrological requirements which is necessary for its successful management and long-term existence. The work looked at 15 equally managed (extensively grazed and/or mowed) perennial, natural grasslands at different levels of drainage resulting in various quality states. To reveal the most habitat-preserving drainage rate, for each site of the habitat 6270*_3 a decrease of groundwater table was identified. As a result a rate that meets ecohydrological requiremets is procured.
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Hodgkinson, KC, JW Terpstra i WJ Muller. "Spatial and Temporal Pattern in the Grazing of Grasses by Sheep Within a Semi-Arid Wooded Landscape." Rangeland Journal 17, nr 2 (1995): 154. http://dx.doi.org/10.1071/rj9950154.
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Grazing the woodlands of semi-arid and arid Australia by domestic stock has extensively collapsed perennial *grass populations and thereby fostered woody plant increase. This study examined the pattern of grazing of individual grass plants by sheep in the landscape of a semi-arid woodland, and a model was developed describing the spatial and temporal influences on the grazing pressure placed on plants. Plants of two widespread perennial grass species differing in palatability, Eragrostis eriopoda and Thyridolepis mitchelliana, were examined weekly in two contrasting periods at the CSIRO Lake Mere Research Facility. The plants were located throughout the landscape in lightly- and heavily- stocked paddocks. Patterns of grazing in space and time were determined by examining the grazing of marked tillers. No preference was shown for previously ungrazed plants and only occasionally were previously grazed plants preferred. Thyridolepis mitchelliana plants were slightly preferred over E. eriopoda plants. Landscape zones receiving water and nutrients from elsewhere were preferred for grazing but the effect was weak. The foliage biomass of herbaceous plants in the immediate vicinity of a grass plant did not influence the number of tillers grazed nor the probability of the plant being grazed. Overall the defoliation of individual plants by sheep was weakly determined by landscape location, stocking level, plant species and prevailing forage on offer. The influence of spatial and temporal variation was small; random grazing of grass plants was the rule. This finding suggests that the grazing pressure on palatable perennial grasses in the paddocks of semi-arid woodlands will be similar across wooded landscapes and that spatial variability in plant mortality could be due to. the combined effect of plant water stress, which varies spatially and temporally, and grazing pressure which varies temporally but not spatially.
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Creamer, Maggie L., Leslie M. Roche, Kristina M. Horback i Tina L. Saitone. "Optimising cattle grazing distribution on rangeland: a systematic review and network analysis". Rangeland Journal 41, nr 5 (2019): 441. http://dx.doi.org/10.1071/rj19066.
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Optimising beef cattle (Bos taurus and Bos indicus) distribution, both spatially and temporally, is one of the most significant challenges associated with managing extensive grazed rangelands. Landscape variability and behavioural patterns of cattle may lead to non-uniform and inefficient forage utilisation, damage to critical habitats, and water quality impairment. In order to overcome these distribution challenges, a large suite of tools have been developed and researched to optimise grazing patterns. The objectives of this synthesis paper are 2-fold: (i) to survey and categorise distribution tools; and (ii) to analyse the connectivity of existing research across academic disciplines to identify and isolate knowledge gaps. A systematic literature review revealed specific types of tools and strategies to improve cattle distribution, which were categorised as either ‘animal’ or ‘environmental manipulations’. Animal manipulations utilise aspects of individual behaviour and herd dynamics to alter grazing patterns, whereas environmental manipulations involve transforming aspects of the animal’s surroundings to overcome challenges associated with inefficient distribution. This review reveals that strategies are overwhelmingly studied in isolation, and that there is potential to increase efficacy by integrating multiple strategies to achieve a desired outcome. Motivated by these findings, an author collaboration network analysis was conducted to investigate connectivity within and among author fields of expertise to understand why more integrated management strategies are not currently studied. Authors were classified into five fields of research: animal behaviour science, animal production science, biophysical rangeland science, economics, and other. The network analysis revealed that communities of authors contributing to papers on enhancing cattle distribution are disjointed. These results suggest that in order to fulfil knowledge gaps about the efficacy and cost of management strategies, there needs to be interdisciplinary engagement with particular attention to strategies that integrate animal and environmental manipulations to enhance cattle grazing distribution on extensively grazed landscapes.
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Kendall, N. R., D. W. Jackson, A. M. Mackenzie, D. V. Illingworth, I. M. Gill i S. B. Telfer. "The effect of a zinc, cobalt and selenium soluble glass bolus on the trace element status of extensively grazed sheep over winter". Animal Science 73, nr 1 (kwiecień 2001): 163–69. http://dx.doi.org/10.1017/s135772980005815x.
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AbstractThe effects of trace element deficiencies in lambs, particularly zinc, copper, cobalt and selenium, include decreased growth rates and increased mortality. However, trace element supplementation of sheep reared under extensive conditions has several logistical problems.Two trials were designed to investigate the effect of a zinc, cobalt and selenium soluble glass bolus on the trace element status of out-wintered ewe lambs. In trial 1 600 8-month-old ewe lambs (500 Scottish Blackface and 100 North Country Cheviots) were allocated to two treatment groups; 300 were treated with a zinc, cobalt and selenium soluble glass bolus (zinc) and 300 were untreated (control). In trial 2, 315 8-month-old Scottish Blackface ewe lambs were allocated to three treatments: 105 were treated with the zinc, cobalt and selenium soluble glass bolus (zinc), 105 were treated with a copper, cobalt and selenium soluble glass bolus (copper) and the remaining 105 were untreated (control). Blood samples were collected immediately prior to giving boluses and again after approximately 4 months. These were assessed for zinc (plasma zinc concentration), cobalt (serum vitamin B12concentration), selenium (erythrocyte glutathione peroxidase activity) and copper status (plasma copper concentration, caeruloplasmin, amine oxidase and superoxide dismutase activity and calculation of the ratio between the caeruloplasmin and plasma copper).The zinc bolus in both trials significantly increased the plasma zinc concentrations (P< 0·001 andP< 0·01 respectively), erythrocyte glutathione peroxidase activities (P< 0·001) and serum vitamin B12concentrations (P< 0·001). The copper bolus also significantly increased the erythrocyte glutathione peroxidase activities (P< 0·001) and serum vitamin B12concentrations (P< 0·001) when compared with the controls but were not significantly different from the zinc group. The copper bolus significantly increased all of the copper status indicators (P< 0·01) when compared with the control and zinc groups. However, in trial 1 when only the zinc and control groups were compared, the zinc bolus significantly increased the ratio (P< 0·001) and serum caeruloplasmin (P< 0·001) and erythrocyte superoxide dismutase (P< 0·01) activities. These responses were not observed in trial 2 with the erythrocyte superoxide dismutase being significantly reduced in the zinc group when compared with the control group (P< 0·001).The zinc, cobalt and selenium soluble glass bolus increased the status of all three trace elements consistently for a period of at least 100 days. The increases of cobalt and selenium status were similar to those achieved using the copper, cobalt and selenium bolus, which also increased the copper status of the sheep.
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Wilson, Brian R., Ivor Growns i John Lemon. "Scattered native trees and soil patterns in grazing land on the Northern Tablelands of New South Wales, Australia". Soil Research 45, nr 3 (2007): 199. http://dx.doi.org/10.1071/sr07019.
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Over large areas of south-eastern Australia, the original cover of native woodland has been extensively cleared or modified, and what remains is often characterised by scattered trees beneath which the ground-storey vegetation is largely grazed or otherwise managed. This study investigated the influence of scattered Blakely’s red gum (Eucalyptus blakelyi) trees on both near-surface and deeper soil layers in temperate grazed pastures on the Northern Tablelands of New South Wales, Australia. A significant canopy effect was observed with elevated soil pH, carbon, and nutrient status inside the tree canopy indicating soil enrichment in a zone around the tree. This effect, however, was largely restricted to the surface (0–0.20 m) soil layers. Chloride concentrations were elevated near to trees but only in the deeper soil layers, suggesting that a modified water use and deep drainage mechanism occurred near the trees. Close to the tree, however, a significant acidification was observed between 0.40–0.60 m depth in the soil, without any obvious depletion in other soil element concentrations. It is concluded that this acidification provides strong evidence in support of a ‘biological pumping’ mechanism that has been proposed elsewhere. Key questions remain as to the management implications of these results, whether the subsurface acidification that was observed is common among native Australian trees, if it might be persistent through time, and if this might be a soil issue that requires management.
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Whalley, R. D. B., J. N. Price, M. J. Macdonald i P. J. Berney. "Drivers of change in the Social-Ecological Systems of the Gwydir Wetlands and Macquarie Marshes in northern New South Wales, Australia". Rangeland Journal 33, nr 2 (2011): 109. http://dx.doi.org/10.1071/rj11002.
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The Murray–Darling Basin is a Social-Ecological System (SES) of major importance to Australia and includes extensive wetland areas in the north-western parts of New South Wales. The Gwydir Wetlands and the Macquarie Marshes are the particular focus of this paper. These two wetland SES have undergone five successive adaptive cycles (phases) since they were first visited by Europeans in the early 19th century and the ecological, economic and social drivers initiating each transformation to a new cycle are described and analysed. The arrival of the European settlers with their domestic livestock rapidly displaced the Indigenous SES and the wetlands were extensively grazed; during wet periods the livestock were moved out of the wetlands and moved back in as the water receded. More recent land-use changes resulted from the building of major dams to enable storage of water for use in irrigated agriculture. A consequence of dam construction and water use has been a reduction in the frequency and extent of flooding, which has allowed many parts of the wetlands to be continually grazed. Furthermore, as machinery capable of cultivating the very heavy textured soils became available, dryland cropping became a major enterprise in areas of the floodplain where the likelihood of flooding was reduced. With the reduction in flooding, these wetland sites have been seriously degraded. The final phase has seen the invasion by an exotic weed, lippia [Phyla canescens (Kunth) Greene], which is a perennial that grows mat-like between other species of plants and spreads to produce a virtually mono-specific stand. The domestic livestock carrying capacity of the land becomes more or less zero and the conservation value of the wetlands is also dramatically decreased. Therefore, we suggest that lippia should be classed as an ecosystem engineer that has caused the latest transformation of these wetland SES and suggest research directions to investigate how they can be managed to revert to a state in which lippia is no longer dominant.
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Felber, R., A. Münger, A. Neftel i C. Ammann. "Eddy covariance methane flux measurements over a grazed pasture: effect of cows as moving point sources". Biogeosciences Discussions 12, nr 4 (24.02.2015): 3419–68. http://dx.doi.org/10.5194/bgd-12-3419-2015.
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Abstract. Methane (CH4) from ruminants contributes one third to global agricultural greenhouse gas emissions. Eddy covariance (EC) technique has been extensively used at various flux sites to investigate carbon dioxide exchange of ecosystems. Since the development of fast CH4 analysers the instrumentation at many flux sites have been amended for these gases. However the application of EC over pastures is challenging due to the spatial and temporal uneven distribution of CH4 point sources induced by the grazing animals. We applied EC measurements during one grazing season over a pasture with 20 dairy cows (mean milk yield: 22.7 kg d−1) managed in a rotational grazing system. Individual cow positions were recorded by GPS trackers to attribute fluxes to animal emissions using a footprint model. Methane fluxes with cows in the footprint were up to two orders of magnitude higher than ecosystem fluxes without cows. Mean cow emissions of 423 ± 24 g CH4 head−1 d−1 (best guess of this study) correspond well to animal respiration chamber measurements reported in the literature. However a systematic effect of the distance between source and EC tower on cow emissions was found which is attributed to the analytical footprint model used. We show that the EC method allows to determine CH4 emissions of grazing cows if the data evaluation is adjusted for this purpose and if some cow distribution information is available.
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McCormick, J. I., J. W. Paulet, L. W. Bell, M. Seymour, M. P. Ryan i S. R. McGrath. "Dual-purpose crops: the potential to increase cattle liveweight gains in winter across southern Australia". Animal Production Science 61, nr 11 (2021): 1189. http://dx.doi.org/10.1071/an19231.
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Context Dual-purpose wheat (Triticum aestivum L.) and canola (Brassica napus L.) crops have been extensively researched for grazing in Australian farming systems, with a focus on grazing by sheep. In some regions, dual-purpose crops have been grazed by cattle, but there have been reports of animal health problems. Aims This paper sought to collate all known experiments conducted throughout Australia of cattle grazing dual-purpose crops, in order to evaluate grazing management options for cattle on dual-purpose crops that result in high growth rates and good animal health outcomes. Methods There were six experiments. In Expts 1–3, cattle were grazed on wheat crops with and without available mineral supplementation of NaCl and MgO in a 1:1 ratio. In Expt 3, lime was also added to the mineral mix. In Expts 4 and 5, dual-purpose crops were grazed in combination with annual pastures to determine whether strategic use of dual-purpose crops could increase whole farm livestock productivity. In Expt 6, cattle were introduced to dual-purpose canola with different periods of adaptation (0, 4 and 7 days). Liveweight gain was monitored regularly to assess differences between adaptation treatments. Key results Liveweight gain was increased by 0–27% when cattle grazing high quality, dual-purpose wheat were provided with mineral supplement. Cattle had an initial lag in growth rate when introduced to dual-purpose canola for grazing and this was not affected by the adaptation strategy used. Cattle that experienced a shorter adaptation period achieved higher weight gains more quickly. After the lag phase, average daily gain (ADG) was ≥2 kg/head.day, with an ADG over the entire grazing period for all treatments of 1.75 kg/head.day. The effect on the farm system was determined by extending the length of the grazing period on the dual-purpose crops. Grazing periods of shorter duration did not increase overall liveweight gains compared with grazing only pasture, whereas extending the period of dual-purpose crop grazing resulted in increased cattle weights. Conclusions Cattle benefit from the addition of mineral supplements when grazing a dual-purpose wheat crop, with a response similar to that previously demonstrated in sheep. Cattle can safely graze dual-purpose canola and achieve high ADG. Inclusion of dual-purpose crops can improve overall cattle performance in the farming system. Implications The potential area for production of dual-purpose crops within the Australian mixed farming zone is large and there may be insufficient livestock numbers within the zone to utilise the potential forage production. Cattle from other regions could be introduced during autumn and winter to realise this large forage potential during a period that is commonly a feed deficit on grazing-only properties. Estimates suggest that up to two million young cattle could be supported for 60 days, increasing liveweight by 90 kg/head.
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van Leeuwen, J. P., D. Moraetis, G. J. Lair, J. Bloem, N. P. Nikolaidis, L. Hemerik i P. C. de Ruiter. "Ecological soil quality affected by land use and management on semi-arid Crete". SOIL Discussions 2, nr 1 (3.03.2015): 187–215. http://dx.doi.org/10.5194/soild-2-187-2015.
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Abstract. Land use and soil management practice can have strong effects on soil quality, defined in terms of soil fertility, carbon sequestration and conservation of biodiversity. In this study, we investigate whether ecological soil quality parameters are adequate to assess soil quality under harsh conditions, and are able to reflect different land uses and intensities of soil management practices. We selected three sites as main representatives for the dominant types of land use in the region: an intensively cultivated olive orchard (annually tilled), an extensively used olive orchard (not tilled) and a heavily grazed pasture site in the Koiliaris catchment (Crete/Greece). Soil quality was analysed using an ecosystem approach, studying soil biological properties such as soil organism biomass and activity, and taxonomic diversity of soil microarthropods, in connection to abiotic soil parameters, including soil organic matter contents, and soil aggregate stability. The intensively cultivated olive orchard had a much lower aggregate water stability than the extensive olive orchard and the pasture. Contents of soil organic C and N were higher in the extensively used olive orchard than in the intensively cultivated orchard, with intermediate concentrations in the pasture. This was mainly caused by the highest input of organic matter, combined with the lowest organic matter decomposition rate. Soil organism biomasses in all sites were relatively low compared to values reported from less harsh systems, while microarthropod richness was highest in the pasture compared to both the intensive and extensive olive orchards. From the present results we conclude that microarthropod taxonomic richness is a very useful indicator for ecological soil quality, because it is not only able to separate harsh sites from other systems, but it is also sensitive enough to show differences between land management practices under harsh conditions. Microbial biomass and especially microarthropod biomass were much lower in our harsh study sites than reported from less affected areas, and have therefore also potential as biological indicators for degradation.
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Felber, R., A. Münger, A. Neftel i C. Ammann. "Eddy covariance methane flux measurements over a grazed pasture: effect of cows as moving point sources". Biogeosciences 12, nr 12 (29.06.2015): 3925–40. http://dx.doi.org/10.5194/bg-12-3925-2015.
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Abstract. Methane (CH4) from ruminants contributes one-third of global agricultural greenhouse gas emissions. Eddy covariance (EC) technique has been extensively used at various flux sites to investigate carbon dioxide exchange of ecosystems. Since the development of fast CH4 analyzers, the instrumentation at many flux sites has been amended for these gases. However, the application of EC over pastures is challenging due to the spatially and temporally uneven distribution of CH4 point sources induced by the grazing animals. We applied EC measurements during one grazing season over a pasture with 20 dairy cows (mean milk yield: 22.7 kg d−1) managed in a rotational grazing system. Individual cow positions were recorded by GPS trackers to attribute fluxes to animal emissions using a footprint model. Methane fluxes with cows in the footprint were up to 2 orders of magnitude higher than ecosystem fluxes without cows. Mean cow emissions of 423 ± 24 g CH4 head−1 d−1 (best estimate from this study) correspond well to animal respiration chamber measurements reported in the literature. However, a systematic effect of the distance between source and EC tower on cow emissions was found, which is attributed to the analytical footprint model used. We show that the EC method allows one to determine CH4 emissions of cows on a pasture if the data evaluation is adjusted for this purpose and if some cow distribution information is available.
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Hezron E, Nonga, Muwonge Adrian i Mdegela Robinson H. "Tick infestations in extensively grazed cattle and efficacy trial of high-cis cypermethrin pour-on preparation for control of ticks in Mvomero district in Tanzania". BMC Veterinary Research 8, nr 1 (2012): 224. http://dx.doi.org/10.1186/1746-6148-8-224.
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Sinden, J. A. "Do the public gains from vegetation protection in north-western New South Wales exceed the landholders' loss of land value?" Rangeland Journal 26, nr 2 (2004): 204. http://dx.doi.org/10.1071/rj04014.
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Protection of native vegetation on farms provides many gains for the public as a whole, but may also lead to losses in property value for the landholders. At least 41% of Moree Plains Shire remains in native vegetation, most of which is grazed extensively and all of which must now be protected under recent laws. A benefit-cost analysis was combined with a risk simulation to estimate these gains and losses. The data collection stage of the analysis included a synthesis of the literature on the relationship between protection and land values. The analysis showed that protection of native vegetation leads to substantial public gains and to considerable losses in land value in this region. The public gains and the private losses are of the same magnitude, so there may be an economic case for protection. But the size of the landholders' losses demonstrates the need to better balance the gains and losses through policies to target protection and to redistribute the costs between the landholder and the community.
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Rodríguez-Rigueiro, Francisco Javier, José Javier Santiago-Freijanes, María Rosa Mosquera-Losada, Marina Castro, Pablo Silva-Losada, Andrea Pisanelli, Anastasia Pantera, Antonio Rigueiro-Rodríguez i Nuria Ferreiro-Domínguez. "Silvopasture policy promotion in European Mediterranean areas". PLOS ONE 16, nr 1 (22.01.2021): e0245846. http://dx.doi.org/10.1371/journal.pone.0245846.
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Silvopasture is the deliberate integration of a woody component with grazed pastures as understorey. It is one of the most extended agroforestry practices all over the world. Silvopasture use is key to increase the sustainability of livestock farming systems as silvopasture reduces the use of concentrates since the woody component provides feed for animals. However, it is not an extensively used practice in Europe. This paper aims at evaluating, from Eurostat, LUCAS database and the 118 rural development programs, the current situation of permanent grasslands in the Mediterranean area of Europe as well as the rural development programmes fostering silvopasture to better understand how sustainable land use systems are promoted and provide insights to foster silvopasture across Europe. The results of this study show that most of the policy measures related to silvopasture are adapted to the local necessity. The already existing agroforestry managed land (dehesas/montado) are related to measures supporting regeneration and maintenance while in those areas where agroforestry does not exist the measures are related to forest fire prevention.
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Robertson, S. M., T. Atkinson, M. A. Friend, M. B. Allworth i G. Refshauge. "Reproductive performance in goats and causes of perinatal mortality: a review". Animal Production Science 60, nr 14 (2020): 1669. http://dx.doi.org/10.1071/an20161.
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Goat meat production is an expanding industry in Australia. However, there is limited data quantifying the levels of reproductive performance, particularly under extensively grazed rangeland conditions, which would inform interventions to improve performance. This review aimed to quantify the levels of reproduction, time and causes of reproductive wastage in goats. It considers the levels of fertility, fecundity, embryonic loss, fetal loss and post-natal survival reported under Australian conditions, and comparisons are made with international reports. Key management factors that may contribute to reproductive performance include breed, seasonality, nutritional conditions, and weather conditions at kidding. While goats are potentially prolific breeders, in Australia, the variation in weaning rate (kids/doe joined) among properties is large (51–165%), although the causes of this variation are not well defined. Generally, conception and kidding rates are high, although fetal loss associated with undernutrition is more likely in goats than sheep. As with sheep, perinatal losses are generally the largest source of wastage, with an average 20% kid mortality, but this level is influenced by litter size and appears to be higher under extensive rangeland systems. The causes of perinatal kid loss under Australian conditions are similar to those in sheep, with starvation–mismothering–exposure and dystocia or stillbirth the key causes. Studies are needed to accurately quantify the level and causes of reproductive wastage in commercial herds, including a range of management situations, to enable effective interventions to be developed.
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Norton, Mark R., Denys L. Garden, Beverley A. Orchard, Philip Armstrong i Trent Brassil. "Effects of lime, phosphorus and stocking rate on an extensively managed permanent pasture: botanical composition and groundcover". Crop and Pasture Science 71, nr 7 (2020): 700. http://dx.doi.org/10.1071/cp20135.
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Low phosphorus (P) constrains productivity of many of the permanent pastures of south-eastern Australia where wool and meat production are important. Whereas the need for fertilisation with P is indisputable for many soils, the benefits of liming to ameliorate soil acidification are not always clear in terms of forage production or quality. This experiment, by measuring botanical composition and groundcover over 10 years, aimed to address the issue of forage composition and groundcover. Merino wethers were continuously grazed on a permanent pasture under two stocking rates (low and high) following treatments with three rates of surface-applied lime and two rates of P. The lime rates were: nil, and sufficient to raise the pHCaCl2 of the 0–10 cm soil layer to 5.0 and to 5.5. Phosphorus was added as two rates of single superphosphate: 125 kg ha–1 every 2–3 years, and 250 kg ha–1 every year. Two hypotheses were proposed: (i) as lime application rate increased, it would lead to the pasture swards having a higher percentage of species favourable for grazing animal production, and a higher level of sward groundcover would be maintained; and (ii) legume presence would be favoured by a higher level of applied P over the long term. The Millennium Drought (1997–2008), which coincided with this experiment (1998–2008), tended to mask or reduce lime effects; nevertheless, the higher legume content in the sward, as well as the superior groundcover found in the high lime–high P treatments at various times throughout the experiment and at its completion compared with the nil-lime control, indicated positive forage effects of lime application. Moreover, by the termination of the experiment in 2008, groundcover generally tended to be lower under nil lime than in treatments that had received lime. The higher proportion of legume in the sward was closely linked to greater applied P, although this did not occur at the low stocking rate in the absence of lime. By contrast, similar high P–low stocking rate treatments but with applied lime had the highest clover contents. It is proposed that the poor persistence of the treatment without lime may be due to a combination of poor legume seedset, because of excessive competition from accompanying grasses, and aluminium toxicity adversely affecting legume growth.
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Ciais, P., J. F. Soussana, N. Vuichard, S. Luyssaert, A. Don, I. A. Janssens, S. L. Piao i in. "The greenhouse gas balance of European grasslands". Biogeosciences Discussions 7, nr 4 (13.08.2010): 5997–6050. http://dx.doi.org/10.5194/bgd-7-5997-2010.
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Abstract. The long-term carbon balance (NBP) of grasslands is estimated by combining scarce multi-year eddy-covariance observations at ecosystem observation sites where information on carbon inputs and harvesting removals is available. Following accounting for carbon leached to rivers, we estimated grasslands to be net carbon sinks of 74±10 g C m−2 yr−1. Uncertainties arise from the small number of sites and the short measurement period. Only 11 sites, out of a total of 20 grassland sites in Europe where eddy covariance systems are installed, were set-up for estimating NBP. These 11 selected sites are representative of intensive management practice and we lack information on disturbance history, such as plowing. This suggests that the grassland NBP estimate is likely biased towards overestimating the sink, compared to the European average. Direct measurements of Net Primary Productivity (NPP) are not possible in grasslands given permanent biomass removal by grazing and mowing, uncertainties in rhizodeposition and production of volatile organic carbon compounds lost to the atmosphere. Therefore, the grassland process-based ecosystem model PASIM was used to estimate the spatial-temporal distribution of NPP, providing a European average value of 750±150 g C across extensively grazed, intensively grazed pastures, and forage production systems. In Europe the NPP of grasslands seems higher than that of croplands and forests. The carbon sequestration efficiency of grasslands, defined as the ratio of NBP to NPP, amounts to 0.09±0.10. Therefore, per unit of carbon input, grasslands sequester 3–4 times more carbon in the soil than forests do, making them a good candidate for managing onsite carbon sinks. When using the 100 yr greenhouse warming potential for CH4 and N2O, their emissions due to management of grasslands together offset roughly 70–80% of the carbon sink. Uncertainties on the European grassland greenhouse gas balance, including CO2, CH4 and N2O fluxes are likely to be reduced in the near future, with data being collected from more sites, and improved up-scaling methods.
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van Delden, Lona, David W. Rowlings, Clemens Scheer i Peter R. Grace. "Urbanisation-related land use change from forest and pasture into turf grass modifies soil nitrogen cycling and increases N<sub>2</sub>O emissions". Biogeosciences 13, nr 21 (7.11.2016): 6095–106. http://dx.doi.org/10.5194/bg-13-6095-2016.
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Abstract. Urbanisation is becoming increasingly important in terms of climate change and ecosystem functionality worldwide. We are only beginning to understand how the processes of urbanisation influence ecosystem dynamics, making peri-urban environments more vulnerable to nutrient losses. Brisbane in South East Queensland has the most extensive urban sprawl of all Australian cities. This research estimated the environmental impact of land use change associated with urbanisation by examining soil nitrogen (N) turnover and subsequent nitrous oxide (N2O) emissions using a fully automated system that measured emissions on a sub-daily basis. There was no significant difference in soil N2O emissions between the native dry sclerophyll eucalypt forest and an extensively grazed pasture, wherefrom only low annual emissions were observed amounting to 0.1 and 0.2 kg N2O ha−1 yr−1, respectively. The establishment of a fertilised turf grass lawn increased soil N2O emissions 18-fold (1.8 kg N2O ha−1 yr−1), with highest emissions occurring in the first 2 months after establishment. Once established, the turf grass lawn presented relatively low N2O emissions for the rest of the year, even after fertilisation and rain events. Soil moisture was significantly higher, and mineralised N accumulated in the fallow plots, resulting in the highest N2O emissions (2.8 kg N2O ha−1 yr−1) and significant nitrate (NO3−) losses, with up to 63 kg N ha−1 lost from a single rain event due to reduced plant cover removal. The study concludes that urbanisation processes creating peri-urban ecosystems can greatly modify N cycling and increase the potential for losses in the form of N2O and NO3−.
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DINESEN, LARS, ALAN CHAMORRO, JON FJELDSÅ i CONSTANTINO AUCCA. "Distribution and habitat description of Junín Rail Laterallus tuerosi, Andean Peru". Bird Conservation International 27, nr 3 (13.02.2017): 388–97. http://dx.doi.org/10.1017/s0959270916000599.
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SummaryDistribution and habitat description of the endangered Junín Rail Laterallus tuerosi were assessed during a field study between 6 and 20 February 2014 in the marshes surrounding Lake Junín in the high Andes of Peru, which is the only known locality for the species. By using point counts and playback, we found the species to be present in the marshland all around the lake, with preference for two clearly defined habitat types: one comprising extensively grazed tussocks of Festuca dolichophylla and the other of rather uniform stands of Juncus balticus with undergrowth, or smaller open spaces, with various low herbs. We estimate the suitable habitat of the species to be a minimum of 100 km2 and based upon our point count data we provide indicative population figures of 6,200 individuals, which is higher than previous estimates. No records were obtained without playback, although five minutes of silent listening prior to playback were used at each point. All records were in vegetation of at least 0.5 m tall and in the marshy edge on muddy ground with less than 20 cm of water depth. Grazing especially by sheep or cattle is a serious threat to the marsh vegetation structure essential for Junín Rail and the rail is also under pressure from fluctuations in water levels accentuated by regulation for hydroelectric power.
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OURA, C. A. L., R. BISHOP, E. M. WAMPANDE, G. W. LUBEGA i A. TAIT. "The persistence of componentTheileria parvastocks in cattle immunized with the ‘Muguga cocktail’ live vaccine against East Coast fever in Uganda". Parasitology 129, nr 1 (10.06.2004): 27–42. http://dx.doi.org/10.1017/s003118200400513x.
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The ‘Muguga cocktail’ live vaccine comprises threeTheileria parvastocks (Muguga, Kiambu 5 and the buffalo-derived Serengeti-transformed) and has been used extensively in Eastern, Central and Southern Africa with an infection and treatment protocol to protect cattle against East Coast fever. We report the characterization of the three component vaccine stocks using a panel of polymorphic micro-satellite and mini-satellite markers and the development of a stock-derived PCR method that distinguishes two of the vaccine stocks. These markers, with the use of a recently developed Reverse Line Blot assay, have enabled us to address four important questions in relation to vaccination. First, how closely related are the vaccine stocks, secondly do all three stocks persist post-vaccination and induce a carrier state, thirdly is there evidence for the transmission of the vaccine stocks and fourthly does vaccination prevent infection with local genotypes? The results show that Muguga and Serengeti-transformed stocks are highly related but very distinct from Kiambu 5 that persists in vaccinated cattle establishing a carrier state. No evidence was obtained for the transmission of vaccine stocks to co-grazed animals, although these animals were infected with up to 8 differentT. parvagenotypes showing there was a significant level of tick challenge. Some of the vaccinated animals become infected with a subset of local genotypes providing evidence for limited vaccine ‘breakthrough’.
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Kingston-Smith, A. H., R. J. Merry, D. K. Leemans, H. Thomas i M. K. Theodorou. "Evidence in support of a role for plant-mediated proteolysis in the rumens of grazing animals". British Journal of Nutrition 93, nr 1 (styczeń 2005): 73–79. http://dx.doi.org/10.1079/bjn20041303.
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The present work aimed to differentiate between proteolytic activities of plants and micro-organisms during the incubation of grass in cattle rumens. Freshly cut ryegrass was placed in bags of varying permeability and incubated for 16 h in the rumens of dairy cows that had previously grazed a ryegrass sward, supplemented with 4 kg dairy concentrate daily. Woven polyester bags (50 μm pore size) permitted direct access of the micro-organisms and rumen fluid enzymes to the plant material. The polythene was impermeable even to small molecules such as NH3. Dialysis tubing excluded micro-organisms and rumen enzymes/metabolites larger than 10 kDa. DM loss was 46·3 % in polyester, 36·2 % in polythene and 38·1 % in dialysis treatments. It is possible that the DM loss within polythene bags occurred due to a solubilisation of plant constituents (e.g. water-soluble carbohydrates) rather than microbial attachment/degradation processes. The final protein content of the herbage residues was not significantly different between treatments. Regardless of bag permeability, over 97 % of the initial protein content was lost during incubationsin situ. Electrophoretic separation showed that Rubisco was extensively degraded in herbage residues whereas the membrane-associated, light-harvesting protein remained relatively undegraded. Protease activity was detected in herbage residues and bathing liquids after all incubationin situtreatments. Although rumen fluid contains proteases (possibly of plant and microbial origin), our results suggest that, owing to cell compartmentation, their activity against the proteins of intact plant cells is limited, supporting the view that plant proteases are involved in the degradation of proteins in freshly ingested herbage.
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Zimmer, Heidi C., Vivienne B. Turner, Jaimie Mavromihalis, Josh Dorrough i Claire Moxham. "Forb responses to grazing and rest management in a critically endangered Australian native grassland ecosystem". Rangeland Journal 32, nr 2 (2010): 187. http://dx.doi.org/10.1071/rj09069.
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Worldwide, temperate grasslands have been extensively cleared for agriculture and urban expansion and the ‘Natural Temperate Grassland of the Victorian Volcanic Plain’ in south-eastern Australia has recently been listed as critically endangered. Because of land clearing, these grasslands now occupy <1% of their original distribution and much of the remaining grassland continues to be grazed by livestock. Although forbs (wildflowers) constitute most of the floristic richness in natural grasslands, few experimental studies have focused on their responses to strategic livestock grazing and rest. This paper reports on the outcomes of five grazing and rest management regimes imposed for 4 years at three sites on the Victorian Volcanic Plain. Seasonal grazing and rest management regimes resulted in significantly different native and exotic forb frequencies, but not richness. Native perennial and exotic annual forb frequency was higher when management incorporated grazing and rest periods (14 and 16% deviance explained), particularly with spring rest from grazing. However, the most important influence on native perennial and exotic annual and perennial forb frequency (46, 58 and 41% deviance explained) and native perennial and exotic annual species richness (62 and 35% deviance explained) was site. Differences among the three sites included soil, rainfall, size of remnant, presence of small burrowing mammals, management history and consequent species assemblages. Despite differences among sites, the results indicate that native perennial forb frequency may be increased using management regimes that incorporate both grazing and rest. However, targeted management may be necessary to reduce exotic annual forbs, also promoted by grazing with seasonal rest.
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Dobicki, A., P. Nowakowski, M. Kierzek, A. Zachwieja i P. Baranowski. "Reproduction behavior and performance of beef cattle herd in free ranging environment of "Warta Mouth" national park". Biotehnologija u stocarstvu 23, nr 5-6-1 (2007): 253–60. http://dx.doi.org/10.2298/bah0701253d.
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The observations conducted on a herd of beef cattle, extensively free grazed, demonstrated that cows in oestrus, breeding bulls (sires) and young bulls showed a wide range of sexual behavior. In the cow-cow relation mutual mounting was a standard sexual behavior, confirmed by 88.9% of observations. In the relation between sire and cow in oestrus, of the four forms of activity initiated by the cow, rubbing against a sire and mounting him was recorded in 100% of observations. The evaluation of the activity of the sire in relation to a cow in oestrus covered seven behavioral forms, of which as standard one may consider: sniffing and rubbing against, tasting the cow?s urine and mounting in an attempt at a sexual act, while mounting ended by a sexual act was not always the standard - 88.9% of observations. Young bulls manifested their sexual behavior by sniffing the cow in oestrus, often attempting to mount, following the sire and being always driven away. Driving away of the rival by a dominant sire was a standard behavior in relations between sires remaining close to a cow in oestrus. During the three year period of studies calving rate averaged 96.5%, while losses of calves as still born or dead during the first day after birth reached 1.5%. The best calving ratio was recorded for Salers cows (98.7%), while beef crossbred, Limousine, Hereford and Simmental cows demonstrated similar results (96.3-97.9%), and cows of the Charolais breed performed significantly (P?0.01) poorer (94.1%). Moreover, in the group of Charolais cows the largest percentage of still born calves (2.3%) was demonstrated.
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FRASER, M. D., H. R. FLEMING, V. J. THEOBALD i J. M. MOORBY. "Effect of breed and pasture type on methane emissions from weaned lambs offered fresh forage". Journal of Agricultural Science 153, nr 6 (22.06.2015): 1128–34. http://dx.doi.org/10.1017/s0021859615000544.
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SUMMARYTo investigate the extent to which enteric methane (CH4) emissions from growing lambs are explained by simple body weight and diet characteristics, a 2 × 2 Latin square changeover design experiment was carried out using two sheep breeds and two fresh pasture types. Weaned lambs of two contrasting breed types were used: Welsh Mountain (WM, a small, hardy hill breed) and Welsh Mule × Texel (TexX, prime lamb) (n = 8 per breed). The lambs were zero-grazed on material cut from recently reseeded perennial ryegrass and extensively managed permanent pasture. In each experimental period, individual ad libitum dry matter intake (DMI) was determined indoors following an adaptation period of 2 weeks, and CH4 emissions were measured individually in open-circuit respiration chambers over a period of 3 days. Although total daily CH4 emissions were lower for the WM lambs than for the TexX lambs (13·3 v. 15·7 g/day, respectively) when offered fresh forage, the yield of CH4 per unit DMI was similar for the two breed types (16·4 v. 17·7 g CH4/kg DMI). Total output of CH4 per day was higher when lambs were offered ryegrass compared with permanent pasture (16·1 v. 12·9 g/day, respectively), which was probably driven by differences in DMI (986 v. 732 g/day). Methane emissions per unit DMI (16·4 v. 17·7 g CH4/kg DMI) and proportion of gross energy intake excreted as CH4 (0·052 v. 0·056 MJ/MJ) were both higher on the permanent pasture. No forage × breed type interactions were identified. The results indicate that forage type had a greater impact than breed type on CH4 emissions from growing weaned lambs. It can be concluded that when calculating CH4 emissions for inventory purposes, it is more important to know what forages growing lambs are consuming than to know what breeds they are.
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Coblentz, Wayne K., i Matthew Akins. "39 Management of cereal-grain forages for yield and quality". Journal of Animal Science 97, Supplement_2 (lipiec 2019): 20–21. http://dx.doi.org/10.1093/jas/skz122.038.
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Abstract Cereal-grains have a long history of providing quality forage for livestock operations. Our objective is to review the existing literature and describe the principle factors controlling the yield and quality of cereal-grain forages. Generally, cereal-grain forage production can occur via management scenarios that include: 1) winter-annuals planted during fall and then grazed or harvested the following spring; 2) cereals not requiring vernalization planted during early spring and harvested during late-spring or summer; and 3) cereals not requiring vernalization planted during late-summer and harvested before winter. Winter-annuals planted during fall also are used extensively for fall grazing, particularly for backgrounding stocker cattle. The requirement for vernalization before plants elongate and produce viable seed plays a large role in synchronizing management strategies with producer goals. For example, maximization of fall growth can be attained by choosing a species or cultivar that does not require vernalization and will elongate, but this choice will likely eliminate winter survival and subsequent spring forage production. Ambient temperature during plant maturation affects lignin formation positively; therefore, forages grown during cooler fall temperatures will typically exhibit greater NDF digestibility than those maturing during summer. Most nutritional characteristics are influenced heavily by two competing processes that include the normal negative maturation effects that reduce the quality of most forages. However, this process is juxtaposed against the physiological process of grain fill, which can dilute concentrations of forage fiber components, increase energy density, and improve DM digestibility at advanced plant-growth stages. Digestibility of NDF declines with plant maturity, and generally is not affected by grain fill. A boot-stage harvest for silage often exhibits the most favorable nutritional characteristics for lactating dairy cows; however, producers making this management choice will need to accept a substantial yield penalty compared with a commonly recommended harvest at soft-dough stage, which would likely maximize yield.