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Articles 12511 - 12540 of 302419

Full-Text Articles in Physical Sciences and Mathematics

Framework For Assessing Information System Security Posture Risks, Syed Waqas Hamdani Jun 2023

Framework For Assessing Information System Security Posture Risks, Syed Waqas Hamdani

Electronic Thesis and Dissertation Repository

In today’s data-driven world, Information Systems, particularly the ones operating in regulated industries, require comprehensive security frameworks to protect against loss of confidentiality, integrity, or availability of data, whether due to malice, accident or otherwise. Once such a security framework is in place, an organization must constantly monitor and assess the overall compliance of its systems to detect and rectify any issues found. This thesis presents a technique and a supporting toolkit to first model dependencies between security policies (referred to as controls) and, second, devise models that associate risk with policy violations. Third, devise algorithms that propagate risk when …

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The Effect Of Dairy Cow Genotype On Modelled Greenhouse Gas Emissions Derived From Pasture Based Milk Production Systems, Dan K. Lovett, L. Shalloo, P. Dillon, Frank O'Mara Jun 2023

The Effect Of Dairy Cow Genotype On Modelled Greenhouse Gas Emissions Derived From Pasture Based Milk Production Systems, Dan K. Lovett, L. Shalloo, P. Dillon, Frank O'Mara

IGC Proceedings (1993-2023)

A three-year systems comparison study was undertaken to see if progressively increasing the genetic potential for milk production of the dairy cow is desirable within pastoral based systems of spring milk production (Kennedy et al., 2002). The production data was inputted into the Moorepark Dairy System Model (MDSM) (Shalloo et al., 2004) to describe the economic, biological and production efficiency of each system. Output was then used to model whole farm greenhouse gas (GHG) emissions (Lovett et al., in press) from the nine systems studied (three concentrate levels by three genotype levels). Only the genotype effects are …

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Methane Of Animal Origin In Cattle Fed High Or Low Tannin Sorghum Silage, T. T. Berchielli, S. G. Oliveira, M. P. Pedreira, O. Primavesi, M. A. Lima, R. Frighetto Jun 2023

Methane Of Animal Origin In Cattle Fed High Or Low Tannin Sorghum Silage, T. T. Berchielli, S. G. Oliveira, M. P. Pedreira, O. Primavesi, M. A. Lima, R. Frighetto

IGC Proceedings (1993-2023)

The harmful or beneficial effects associated with the presence of tannin in plants depends on its concentration and form. One of these beneficial effects is the reduction of the production of methane in the rumen (Woodward et al., 2001). This study financed by FAPESP aimed to evaluat the effect of diets containing low or high tannin sorghum silage supplements on dry matter intake (DMI) and methane production in cattle.

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Field Measurements Of Ruminal Methane Of Cattle Grazing Tropical Grasses, M. P. Pedreira, O. Primavesi, M. A. Lima, R. Frighetto, T. T. Berchielli Jun 2023

Field Measurements Of Ruminal Methane Of Cattle Grazing Tropical Grasses, M. P. Pedreira, O. Primavesi, M. A. Lima, R. Frighetto, T. T. Berchielli

IGC Proceedings (1993-2023)

Ruminal methane production represents energy losses from ingested feed that should be utilised to maintain body weight or to generate products. Quantitatively, daily methane production varies according to amount and quality of ingested dry matter (DM), as well as physiological status of the animal.

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Hedgerow Systems And Livestock In Philippine Grasslands: Ghg Emissions, D. B. Magcale-Macandog, E. Abucay, R. G. Visco, R. N. Miole, E. L. Abas, G. M. Comajig, A. D. Calub Jun 2023

Hedgerow Systems And Livestock In Philippine Grasslands: Ghg Emissions, D. B. Magcale-Macandog, E. Abucay, R. G. Visco, R. N. Miole, E. L. Abas, G. M. Comajig, A. D. Calub

IGC Proceedings (1993-2023)

Hedgerow systems are widely adopted in the smallholder farms in the sloping grassland areas of Claveria, Mindanao, Philippines. The system is effective in addressing soil erosion problems and in conserving the topsoil. Gmelina arborea and Eucalyptus deglupta are two fast-growing timber species that are planted in hedgerow systems while maize is planted in the alley areas in between the hedgerows. Livestock holdings are widespread in Claveria, with 74% of the households having livestock. Cattle and carabao are the most common livestock in smallholder farms providing draught power for land preparation and transportation. In hedgerow systems, fodder tree leaves and crop …

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The Effect Of Soil Type And Climate On Modelled Greenhouse Gas Emissions Derived From Pasture Based Milk Production Systems, Dan K. Lovett, L. Shalloo, P. Dillon, Frank O'Mara Jun 2023

The Effect Of Soil Type And Climate On Modelled Greenhouse Gas Emissions Derived From Pasture Based Milk Production Systems, Dan K. Lovett, L. Shalloo, P. Dillon, Frank O'Mara

IGC Proceedings (1993-2023)

The ability of spring calving dairy farmers to exploit herbage production can be limited by soil type and climatic conditions. Previous work, using the Moorepark Dairy System Model (MDSM) (Shalloo et al., 2004) demonstrated differences in terms of biological and production efficiency for two contrasting sites. This study models whole farm greenhouse gas (GHG) emissions (Lovett et al., in press) from two dairy systems, the Moorepark Standard System (MSS, Co. Cork) and the Kilmaley Standard System (KSS,Co. Clare), classified as lower and high rainfall (1025 and 1614 mm yr) and free draining versus poor draining respectively.

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Quantification Of Co2 Exchange In Grassland Ecosystems Of The World Using Tower Measurements, Modeling And Remote Sensing, Tagir Gilmanov, M. W. Demment, B. K. Wylie, K. Akshalov, D. D. Baldocchi, L. Belelli, J. A. Bradford, G. G. Burba, R. L. Coulter, W. A. Dugas, W. E. Emmerich, L. B. Flanagan, A. B. Frank, J. Fuher, M. R. Haferkamp, M. B. Jones, D. A. Johnson, T. Laurila, A. Lohila, T. P. Meyers, P. C. Mielnick, J. A. Morgan, M. Nasyrov, C. E. Owensby, M. S. Pekour, K. Pilegaard, A. Raschi, N. Z. Saliendra, M. J. Sanz, P. L. Sims, R. H. Skinner, J. F. Sousanna, A. E. Suyker, L. L. Tieszen, Z. Tuba, R. Valentini, S. B. Verma, E. A. Laca Jun 2023

Quantification Of Co2 Exchange In Grassland Ecosystems Of The World Using Tower Measurements, Modeling And Remote Sensing, Tagir Gilmanov, M. W. Demment, B. K. Wylie, K. Akshalov, D. D. Baldocchi, L. Belelli, J. A. Bradford, G. G. Burba, R. L. Coulter, W. A. Dugas, W. E. Emmerich, L. B. Flanagan, A. B. Frank, J. Fuher, M. R. Haferkamp, M. B. Jones, D. A. Johnson, T. Laurila, A. Lohila, T. P. Meyers, P. C. Mielnick, J. A. Morgan, M. Nasyrov, C. E. Owensby, M. S. Pekour, K. Pilegaard, A. Raschi, N. Z. Saliendra, M. J. Sanz, P. L. Sims, R. H. Skinner, J. F. Sousanna, A. E. Suyker, L. L. Tieszen, Z. Tuba, R. Valentini, S. B. Verma, E. A. Laca

IGC Proceedings (1993-2023)

Grasslands cover significant areas in nontropical regions, perform essential biogeochemical functions and represent important natural and agricultural resource. Nevertheless, in contrast to forests and agroecosystems, no flux measurement-based global summary of their CO2 exchange, sequestration potential, and role in mitigation of the greenhouse effect were available.

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The Influence Of Local Immigration And Extinction Of Species On Spatial Heterogeneity Of Vegetation In Semi-Natural Grasslands In Japan, Taisuke Yasuda, Masae Shiyomi, T. Egawa, K. Sei, R. Ishikawa, S. Takahashi Jun 2023

The Influence Of Local Immigration And Extinction Of Species On Spatial Heterogeneity Of Vegetation In Semi-Natural Grasslands In Japan, Taisuke Yasuda, Masae Shiyomi, T. Egawa, K. Sei, R. Ishikawa, S. Takahashi

IGC Proceedings (1993-2023)

Spatiotemporal variation in the local immigration and extinction of species in a community may form and change the spatial heterogeneity (SH) of vegetation but few studies have evaluated the influences of these processes on SH. SH often occurs in grassland grazed by cattle and sheep. Understanding the formation and dynamics of SH is important because SH profoundly affects local and regional ecological processes. We propose a new way to quantify the effect of the local immigration and extinction of species on SH, and try to clarify the influence of the processes on SH

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Cattle Slurry Amended With Nitrification Inhibitors: Effects On Nitrous Oxide, Dinitrogen And Methane Emissions, J. P. Carneiro, L. Cardenas, D. Hatch, H. Trindade, J. Hawkins, David Scholefield, D. Chadwick Jun 2023

Cattle Slurry Amended With Nitrification Inhibitors: Effects On Nitrous Oxide, Dinitrogen And Methane Emissions, J. P. Carneiro, L. Cardenas, D. Hatch, H. Trindade, J. Hawkins, David Scholefield, D. Chadwick

IGC Proceedings (1993-2023)

In recent decades, a very intensive dairy farming system has been developed in northern Portugal. Considering the appreciable amounts of slurry generated and the small farm areas for spreading, this activity involves large annual inputs of N with the risk of undesirable consequences for the environment. Emission of greenhouse gases from agricultural sources, such as N2O (originating from nitrification and denitrification) and CH4, therefore need to be reduced. The aim of this laboratory experiment was to evaluate the effectiveness of two nitrification inhibitors (dicyandiamide (DCD) and 3,4-dimethylpyrazole phosphate (DMPP)) in reducing nitrification and subsequent denitrification after …

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Methane Production By Cattle Grazed At Two Stocking Rates On A Semi-Natural Grassland, Cesar S. Pinares-Patiño, Y. Rochette, M. Fabre, J.-P. Jouany, C. Martin Jun 2023

Methane Production By Cattle Grazed At Two Stocking Rates On A Semi-Natural Grassland, Cesar S. Pinares-Patiño, Y. Rochette, M. Fabre, J.-P. Jouany, C. Martin

IGC Proceedings (1993-2023)

Global warming induced by the human-enhanced concentrations of greenhouse gases (GHG) in the atmosphere is a major environmental concern of our day. Enteric methane (CH4) is the most important GHG associated with grazing livestock. The emissions of methane may be influenced by environmental conditions and grazing management. Stocking rate (SR), the number of animals per unit of land area, remains the simplest management tool in pastoral farming. However, little is known about the influence of SR on CH4 emission. The objective of this study was to compare the CH4 emissions from cattle managed under low and …

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Carbon Accumulation Under Brachiaria Pastures In The Brazilian Cerrado In Relation To Their Productivity, R. M. Boddey, S. P. Braz, R. S. M. Dos Santos, B. J. R. Alves, S. Urquiaga Jun 2023

Carbon Accumulation Under Brachiaria Pastures In The Brazilian Cerrado In Relation To Their Productivity, R. M. Boddey, S. P. Braz, R. S. M. Dos Santos, B. J. R. Alves, S. Urquiaga

IGC Proceedings (1993-2023)

Vast areas of land within Brazil has been converted from either the native vegetation of the Amazon and Atlantic forests or the native vegetation (NV) of the central savanna region (the Cerrado) to Brachiaria spp pastures. Productive pastures (PPs) in these regions eventually accumulate soil carbon (C) in excess of levels under native vegetation. However the effect of pasture degradation on soil C stocks has not been reported. We compared soil C stocks under both NV and Brachiaria pastures varying in productivity according to the indicators of Oliveira et al. (2004) over 5 sites in the Cerrado region.

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Comparison Of Methodological Tools In Tropical Soil Carbon Sequestration Field Research, Bram Van Putten, M. C. Amézquita Jun 2023

Comparison Of Methodological Tools In Tropical Soil Carbon Sequestration Field Research, Bram Van Putten, M. C. Amézquita

IGC Proceedings (1993-2023)

Models play a crucial role in studying complex systems like soil Carbon sequestration processes (Hanson et al., 2001). A Carbon sequestration research project is currently under way in pasture and silvopastoral systems of four Tropical American ecosystems. A main research question is the identification of Land Management Systems (LMS) that exhibit optimal soil Carbon sequestration capacity (identification question). Another main issue is the extrapolation of data in space and time (extrapolation question).

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Effects Of Tropical Legumes With Contrasting Tannin Contents And Mixtures Of Them On In Vitro Ruminal Fermentation And Methanogenesis, H. D. Hess, F. L. Valencia, P. Avila, C. E. Lascano, Michael Kreuzer Jun 2023

Effects Of Tropical Legumes With Contrasting Tannin Contents And Mixtures Of Them On In Vitro Ruminal Fermentation And Methanogenesis, H. D. Hess, F. L. Valencia, P. Avila, C. E. Lascano, Michael Kreuzer

IGC Proceedings (1993-2023)

Previous in vitro experiments have showed that the supplementation of a low-quality grass diet with Arachis pintoi or Cratylia argentea (legumes low in tannins) enhanced ruminal fermentation and methane release, whereas the supplementation with Calliandra calothyrsus (rich in tannins) decreased methane release and suppressed organic matter (OM) degradation and N turnover (Hess et al., 2003). It was hypothesised that a mixture of tanniniferous legumes with legumes free of or low in tannins would result in a methane-suppressing effect but without impairing ruminal nutrient degradation.

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A Simulation Study Of Nitrous Oxide Emissions From A Fertilised, Grazed Grassland Site In Ireland, Michael J. Hawkins, J. Connolly, B. Hyde, M. Ryan, R. P. O. Schulte Jun 2023

A Simulation Study Of Nitrous Oxide Emissions From A Fertilised, Grazed Grassland Site In Ireland, Michael J. Hawkins, J. Connolly, B. Hyde, M. Ryan, R. P. O. Schulte

IGC Proceedings (1993-2023)

Nitrous oxide (N2O) emissions from grazed grassland are understood to be strongly influenced by the availability of a mineral N source, soil temperature and soil water content (Skiba & Smith, 2000). We derive an empirical model of emissions based on these factors and use it to simulate daily emissions from a fertilised, grazed grassland site in Wexford, Ireland, under different application schedules and climatic conditions for the period 1994 to 2001, inclusive (Table 1).

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Cattle Overwintering Areas In Middle-European Conditions - Important “Point” Sources Of Nitrous Oxide Emissions, M. Šimek, J. Hynšt, P. Brůček, J. Čuhel, D. Elhottová, H. Šantrůčková, V. Kamír Jun 2023

Cattle Overwintering Areas In Middle-European Conditions - Important “Point” Sources Of Nitrous Oxide Emissions, M. Šimek, J. Hynšt, P. Brůček, J. Čuhel, D. Elhottová, H. Šantrůčková, V. Kamír

IGC Proceedings (1993-2023)

Nitrous oxide (N2O) emissions in grazed grasslands are strongly influenced by animal excreta (Fowler et al., 1997). In addition, soil compaction caused by animal traffic significantly influences soil physical conditions and thus directly or indirectly impacts on the microbial processes producing N2O. In the Czech Republic pastures are mostly located in hilly and mountain areas. During the growing season, cattle are typically grazing, while during the winter the animals are concentrated near the animal house on a relatively small plot called an "overwintering area". The objective of this study was to estimate the fluxes of …

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Modelling Nitrous Oxide Emissions From Grazed Grasslands In New Zealand, Surinder Saggar, D. L. Giltrap, C. Li, Carolyn B. Hedley, K. R. Tate, S. Lambie Jun 2023

Modelling Nitrous Oxide Emissions From Grazed Grasslands In New Zealand, Surinder Saggar, D. L. Giltrap, C. Li, Carolyn B. Hedley, K. R. Tate, S. Lambie

IGC Proceedings (1993-2023)

Spatial and temporal variability are major difficulties when quantifying annual N2O fluxes at the field scale. New Zealand currently relies on the IPCC default methodology (National Inventory Report, 2004). This methodology is too simplistic and generalised as it ignores all site-specific controls, but is also not sufficiently flexible to allow mitigation options to be assessed. Therefore, a more robust, process-based approach is required to quantify N2O emissions more accurately at the field level. Denitrification-decomposition (DNDC) is a process-based model originally developed (Li et al., 1992) to quantify agricultural nitrous oxide (N2O) emissions across …

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Modelling Effects Of Agricultural Policies On Regional Greenhouse Gas Emissions From Cattle Raising Production Systems In Baden-Württemberg (Southwest Germany), Henry Neufeldt, M. Schäfer, E. Angendt, M. Kaltschmitt, J. Zeddies Jun 2023

Modelling Effects Of Agricultural Policies On Regional Greenhouse Gas Emissions From Cattle Raising Production Systems In Baden-Württemberg (Southwest Germany), Henry Neufeldt, M. Schäfer, E. Angendt, M. Kaltschmitt, J. Zeddies

IGC Proceedings (1993-2023)

In the light of the anthropogenic climate change and the resulting need to mitigate greenhouse gas (GHG) emissions, policies are needed which efficiently abate GHG emissions in the agricultural sector. However, reliable estimates of regional GHG abatement potentials in the agricultural sector are rare because the models do not integrate the economic and environmental effects of different agricultural policies and are generally restricted to a single-gas approach. Coupling an economic sector model with a process-oriented ecosystem model can overcome this gap and thus provide realistic exante information of socioeconomically and environmentally sustainable agricultural policies.

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Nitrogen Fluxes In Grassland In Response To Inter-Annual Climate Variability, Pierluigi L. Calanca, Juerg Fuhrer Jun 2023

Nitrogen Fluxes In Grassland In Response To Inter-Annual Climate Variability, Pierluigi L. Calanca, Juerg Fuhrer

IGC Proceedings (1993-2023)

Most model studies dealing with the response of grassland dynamics to climate change (e.g. Thornley & Cannell, 1997; Riedo et al., 2000) consider either step changes or a smooth transition in the climatic drivers, therefore neglecting short-term variations. However, the inter-annual variability of the climatic and edaphic elements (Calanca, 2004) can be substantial, with important consequences for the fluxes of nitrogen (N). The objective of this study is to investigate the response of nitrogen fluxes to this type of variability with the help of the Pasture Simulation Model (PaSim), looking at years considerably differing in terms of temperature, radiation …

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Potential Climate Change Impacts On Beef Production Systems In Australia, David H. Cobon, K. L. Bell, G. M. Mckeon, J. F. Clewett, S. Crimp Jun 2023

Potential Climate Change Impacts On Beef Production Systems In Australia, David H. Cobon, K. L. Bell, G. M. Mckeon, J. F. Clewett, S. Crimp

IGC Proceedings (1993-2023)

There is increasing evidence suggesting that Australia's climate is changing due to enhanced levels of greenhouse gases and that it will continue to change (Pittock 2003). Climate changes are partly established, however the impact on systems, industries and process are unclear. Industry distribution reflects climatically imposed boundaries and the relative profitability of alternative land use. Climate change may negatively impact some existing industries but create opportunities for others. This study provides an assessment of the likely impacts of plausible climate change on the beef industry in central Queensland.

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Targeted Seasonal Climate Forecasts Offer More To Pastoralists, David H. Cobon, J. N. Park, K. L. Bell, I. W. Watson, W. Fletcher, M. Young Jun 2023

Targeted Seasonal Climate Forecasts Offer More To Pastoralists, David H. Cobon, J. N. Park, K. L. Bell, I. W. Watson, W. Fletcher, M. Young

IGC Proceedings (1993-2023)

The existing forecast systems such as the Southern Oscillation Index (SOI) phase system (Stone et al., 1996) and the Sea Surface Temperature (SST) phase system (Drosdowsky 2002) produce rolling three monthly forecasts with lead-times of either zero (SOI phase) or 1 month (SST phase). Both forecasts are reissued monthly. This approach leaves little time for pastoralists to consider the forecast and then make changes to management decisions. In addition the forecast period can often be of little interest because of the seasonal pattern of rainfall.

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Yield Progress Of Perennial Ryegrass And Silage Maize - Genetic Gain Or Climate Change?, Antje Herrmann, A. Kornher, Friedhelm Taube Jun 2023

Yield Progress Of Perennial Ryegrass And Silage Maize - Genetic Gain Or Climate Change?, Antje Herrmann, A. Kornher, Friedhelm Taube

IGC Proceedings (1993-2023)

Gains in annual dry matter yield (DMY) from breeding achieved during the last decades are reported to range between 2.5 and 6% per decade for perennial ryegrass (Wilkins & Humphreys, 2003). In contrast, accelerated progress in improving DMY has been achieved for silage maize, varying between 8 and 13% per decade (Lauer et al., 2001). These gains are mainly attributed to (i) genetic yield potential increase, (ii) improved crop management and (iii) increased stress tolerance. The potential impact of climate change on yield progress, however, is disregarded in most studies. The objective of this study therefore was to quantify …

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Shifts In N-Efficiency Of Different Farm Types In Response To Climate Change, S. Dueri, P. L. Calanca, Juerg Fuhrer Jun 2023

Shifts In N-Efficiency Of Different Farm Types In Response To Climate Change, S. Dueri, P. L. Calanca, Juerg Fuhrer

IGC Proceedings (1993-2023)

Climate change may affect European farms, but in contrast to individual crops - the sensitivity of whole farming systems has not been the subject of much research. At the farm level, where different farm units are linked through the availability and flow of nitrogen (N), effects on individual crops are interlinked, and through shifts in grasslands and related animal production with altered nutrient flows. Ideally, N flows into the system and N-export with products should be equal, and thus N-use-efficiency (NUE), expressed as the ratio of N export to N loss, would be maximal. The objective of this study was …

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The Effect Of Extremes In Soil Moisture Content On Perennial Ryegrass Growth, A. Scott Laidlaw Jun 2023

The Effect Of Extremes In Soil Moisture Content On Perennial Ryegrass Growth, A. Scott Laidlaw

IGC Proceedings (1993-2023)

Seasonal distribution of rainfall in the UK and Ireland is predicted to become more variable (Sweeney, 2003). The problems of excessive soil moisture on grass utilisation and the effect of deficit in soil moisture on grass growth are well known. However the effect of excess rainfall on the growth of sown grass is less clear and is usually not taken into account in grass growth models. This study was carried out to investigate the potential impact of excess moisture on perennial ryegrass growth in the field and to investigate the relative effect of soil moisture varying from deficit to excess …

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Forage Grass Phenology In Relation To Climate Change, G. Żurek Jun 2023

Forage Grass Phenology In Relation To Climate Change, G. Żurek

IGC Proceedings (1993-2023)

Phenological phases of plants, such as heading or flowering are mainly driven by environmental factors such as pests, diseases, competition, soil properties, genetics, age and, most importantly, weather conditions (Menzel & Fabian, 1999; Menzel 2000). At the end of the last century there was an emerging recognition that phenological records can be especially useful in environmental monitoring and it has gained the UK government approval as an indicator of climate change (Sparks et al., 2000). The aim of this work was to analyse long-term trends in the mean heading date for Polish ecotypes of three forage grass species.

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Long-Term Responses Of A Mesic Grassland To Manipulation Of Rainfall Quantity And Pattern, A. K. Knapp, J M. Blair, P. A. Fay, M. D. Smith, S. L. Collins, J. M. Briggs Jun 2023

Long-Term Responses Of A Mesic Grassland To Manipulation Of Rainfall Quantity And Pattern, A. K. Knapp, J M. Blair, P. A. Fay, M. D. Smith, S. L. Collins, J. M. Briggs

IGC Proceedings (1993-2023)

Climatic variability is an inherent feature of grassland biomes, with large fluctuations in temperatures combined with precipitation regimes characterised by floods and severe drought occurring on both an interannual and seasonal scale. Global climate models and emerging data indicate that extremes in precipitation regimes are increasing worldwide coupled with increases in temperature. Thus, variability in spatial and temporal patterns of water availability in grasslands, as directly influenced by altered precipitation patterns and indirectly by increased temperatures, will likely increase in the future. The objectives of our experiments were to experimentally manipulate rainfall amount and temporal patterns (amount and timing of …

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Dynamics Of Long-Term Carbon Sequestration On Rangelands In The Western Usa, G. E. Schuman, L. J. Ingram, P. D. Stahl, G. F. Vance Jun 2023

Dynamics Of Long-Term Carbon Sequestration On Rangelands In The Western Usa, G. E. Schuman, L. J. Ingram, P. D. Stahl, G. F. Vance

IGC Proceedings (1993-2023)

Rangelands in the USA occupy 161 million hectares of land. Worldwide, rangelands occupy about half of the land area and account for more than 1/3 of the world's terrestrial carbon (C) reserves. Because of their large land area, rangelands have the potential to sequester a significant amount of additional atmospheric C. Schuman et al. (2001) estimate that rangelands and marginal croplands restored to grasslands in the USA can sequester 64 million metric tonnes C/ha/yr if properly managed. The objective of this research was to evaluate the long-term effects of grazing on soil C storage in a northern mixed-grass prairie (NMP).

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Lactating Ewes Were Strongly Attracted To Salt When Spread On Sodium-Deficient Undergrazed Hill Pastures, N. Mandaluniz, J. C. Ruiz, R. J. Lucas Jun 2023

Lactating Ewes Were Strongly Attracted To Salt When Spread On Sodium-Deficient Undergrazed Hill Pastures, N. Mandaluniz, J. C. Ruiz, R. J. Lucas

IGC Proceedings (1993-2023)

New Zealand hill and high country pastures for sheep and cattle cover very variable topography. Shady south face hill country pastures on steeper slopes are grazed inefficiently because of their mature state and low nutritive value. Flatter more fertile areas reflect more frequent defoliation and stock camping behaviour. These inland pastures are deficient in sodium (Na) (Aspinall et al., 2004) because they are distant from coastal sea spray. Management alternatives are sought to improve pasture quality on steep, shady aspects. The provision of different nutrients such as Na or nitrogen (N), which are deficient in these under-grazed areas of …

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Toxicity In Beef Cattle Grazing Leucaena Leucocephala In Queensland, Australia, Scott A. Dalzell, D. J. Burnett, J. E. Dowsett, V. E. Forbes, H. M. Shelton Jun 2023

Toxicity In Beef Cattle Grazing Leucaena Leucocephala In Queensland, Australia, Scott A. Dalzell, D. J. Burnett, J. E. Dowsett, V. E. Forbes, H. M. Shelton

IGC Proceedings (1993-2023)

Improved pastures based on the leguminous shrub Leucaena leucocephala (leucaena) are the most productive, profitable and sustainable for beef cattle production in northern Australia. Leucaena forage contains the toxic, non-protein amino acid mimosine, which is rapidly converted to 3-hydroxy-4(1H)-pyridone (DHP) upon ingestion by grazing cattle. This is a potent goitrogen and appetite suppressant. Animals suffering severe DHP toxicity exhibit distinctive symptoms (e.g. hair loss, excessive salivation, goitre and weight loss), while subclinical DHP toxicity can suppress live weight gain by 30-50% without producing any obvious symptoms. Prior to the discovery and introduction of the DHP-degrading rumen bacteria Synergistes jonesii into …

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Simulations Of Woodland Grassland Transitions Caused By Elephant, Kevin J. Duffy, S. Moyo Jun 2023

Simulations Of Woodland Grassland Transitions Caused By Elephant, Kevin J. Duffy, S. Moyo

IGC Proceedings (1993-2023)

In South Africa, reintroduction of wildlife on small to medium sized farms is common. A primary concern for the landowners who introduce elephant is the effects they will have on tree and grass densities. It is possible that elephant impact can exacerbate a shift from woodland to grassland. In this paper it is shown how simulations can possibly assist in understanding the possible dynamics involved.

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Cattle Grazing Management Effects On Pasture Composition In Semi-Arid Woodlands, Trevor J. Hall, J. R. Douglas Jun 2023

Cattle Grazing Management Effects On Pasture Composition In Semi-Arid Woodlands, Trevor J. Hall, J. R. Douglas

IGC Proceedings (1993-2023)

Manipulating grazing pressure, controlling tree competition and burning are the main options for cattle farmers to manage land in subtropical Australian Eucalypt woodlands. These can contain >175 herbaceous and 60 woody species, but only 5 are desirable perennial and productive grass (Silcock et al., 1996). Here we describe the responses of some perennial grasses to cattle grazing pressure, tree competition and spring burning.

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