Agricultural Science Commons^™

Optimising Financial Return From Grazing In Temperate Pastures, P. Dillon, J. R. Roche, L. Shalloo, B. Horan

IGC Proceedings (1977-2023)

Key Points

1. The increased interest in pasture-based systems of milk production in recent years has been largely generated through lower product prices and rising costs of production.

2. Pasture based systems of milk production decrease unit production costs, through lower feed and labour expenses, and reduced capital investment.

3. Systems utilising grazed pasture will be optimised in regions where pasture production potential is high, variability in seasonal pasture supply and quality is low, manufacturing milk accounts for a large proportion of total production, and where large areas of land are available at relatively low cost.

4. Pasture based systems may allow greater global …

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Challenges And Opportunities For Animal Production From Temperate Pastures, D. A. Clark

IGC Proceedings (1977-2023)

Key points

1. Temperate pastures offer a major opportunity to reduce the feed costs associated with ruminant production.

2. Pastures offer unique opportunities for producing high value components in feedstuffs that are beneficial to human health.

3. The increased use of pasture will not automatically lead to improved environmental outcomes – difficult challenges exist in reducing nitrogen and greenhouse gas pollution.

4. Grazed pasture systems offer advantages in animal welfare, provided management avoids the problems associated with climatic extremes, and the toxins associated with some pastures.

5. To remain competitive with total mixed ration systems, and environmentally acceptable, pastures with higher intake characteristics that allow …

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Decision Support For Temperate Grasslands: Challenges And Pitfalls, J. R. Donnelly, L. Salmon, R. D. H. Cohen, Zl. Liu, Xp. Xin

IGC Proceedings (1977-2023)

Key points

1. Successful adoption of decision support tools (DS tools) to address grassland management issues requires careful attention in design to ensure ease-of-use, accuracy in prediction and the flexibility to simulate actual practices.

2. DS tools must handle spatial variability and where possible include facilities for automatic sourcing of essential information for initialisation.

3. Advances in the development of DS tools will depend on resolution of scientific issues in grassland biology including investment in dedicated experiments to determine parameter values for model equations.

4. The use of mechanistic models, the integration of remote sensing technology and cooperation between research groups to develop modular …

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Modelling Of Herbage Intake And Milk Production By Grazing Dairy Cows, Rémy Delagarde, M. O'Donovan

IGC Proceedings (1977-2023)

Key-points

1. Models predicting intake and performance of grazing ruminants from animal, sward, grazing and supplements characteristics are rare, but they are now included in several decision support systems (DSS).

2. An evaluation of the performance and accuracy of published models are rarely undertaken by their authors, but this is proposed in this paper.

3. There is still a need for experimental research but also for the development of generic and dynamic models to predict intake and performance over a wide range of grazing conditions.

Grass Growth Modelling: To Increase Understanding And Aid Decision Making On-Farm, P. D. Barrett, A. S. Laidlaw

IGC Proceedings (1977-2023)

Key points

1. Crop and grass growth models have been developed over the last 50 years, or so, but general appreciation of their benefits and potential has been recognised only relatively recently. The most popular application of grass growth models has traditionally been for knowledge understanding.

2. There is growing awareness of the potential of models in decision support systems (DSS) applications to aid pasture management and grassland budgeting on dairy farms.

3. Although some models have been developed for DSS, their widespread uptake in industry has been slow; challenges still exist which need to be addressed in order to improve their precision …

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Genetic Characteristics Required In Dairy And Beef Cattle For Temperate Grazing Systems, F. Buckley, C. Holmes, M. G. Keane

IGC Proceedings (1977-2023)

Key points

1. Only about 10% of the world’s milk is produced from grazing systems. Consequently the majority of dairy cattle have not been selected under grazing, nor on seasonal systems. This is not true for beef cattle, for which the majority, especially the dams, are managed under seasonal grazing systems.

2. In grazing systems daily feed intake is limited to lower levels than are achievable on concentrate plus conserved forage rations. Consequently, cows most suited to grazing environments are likely to have a lower genetic potential for milk production than cows selected in high concentrate systems, to minimise their relative energy …

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New Insights Into The Nutritional Value Of Grass, D. H. Rearte

IGC Proceedings (1977-2023)

Key points

1. The rumen environment in cattle grazing high quality forage is different to that reported for cattle fed indoors with diets based on processed feedstuffs.
2. Temperate pasture is an excellent source of nutrients for ruminants but a high energy:protein imbalance can occur when it is offered at the stage of optimal digestion.
3. Beef and milk produced on grass in temperate regions have a composition with nutritional advantages over beef or milk produced in indoor systems based on concentrate.
4. Increasing water soluble carbohydrate content of grasses would diminish environmental contamination by reducing the excretion of urea through the urine.
5. Increasing …

Plant And Sward Characteristics To Achieve High Intake In Ruminants, W. J. Wales, C. R. Stockdale, P. T. Doyle

IGC Proceedings (1977-2023)

Key points

1. Intake is affected by complex interactions between signals from the digestive tract, intermediary metabolism and energy supply, and behavioural signals associated with learned behaviours or sensory signals.
2. The ideal sward needs to have characteristics that are similar to total mixed rations to achieve high intake and animal performance.
3. Genetic manipulation of plants may offer an accelerated rate of plant improvement, but benefits need to be demonstrated in a systems context.

Overview Of Animal Production From Pastures In Ireland, M. J. Drennan, A. F. Carson, S. Crosse

IGC Proceedings (1977-2023)

Key points

The importance of grassland to agriculture in Ireland is indicated by the fact that:

1. Sixty percent of agricultural output is from grassland as cattle, milk and sheep products.
2. Over 90% of the total farmed area is in grass.
3. Livestock are almost entirely dependent on grazed grass for 200 to 235 days of the year.
4. Grass conserved as silage is the main source of fodder in winter.
5. To improve competitiveness changes are continuously taking place, which include:

• increased suckler herd size and a movement to late maturing continental cattle breeds;
• movement in the dairy herd towards Holstein with increased …

Pearl Millet Response To Drought: A Review, Nikee Shrestha, Hao Hu, Kumar Shrestha, Andrew N. Doust

Department of Agronomy and Horticulture: Faculty Publications

The C4 grass pearl millet is one of the most drought tolerant cereals and is primarily grown in marginal areas where annual rainfall is low and intermittent. It was domesticated in sub-Saharan Africa, and several studies have found that it uses a combination of morphological and physiological traits to successfully resist drought. This review explores the short term and long-term responses of pearl millet that enables it to either tolerate, avoid, escape, or recover from drought stress. The response to short term drought reveals fine tuning of osmotic adjustment, stomatal conductance, and ROS scavenging ability, along with ABA and ethylene …

Expression Of Malic Enzyme Reveals Subcellular Carbon Partitioning For Storage Reserve Production In Soybeans, Usda Agricultural Research Service, Donald Danforth Plant Science Center, Donald Danforth Plant Science Center, Thomas E. Clemente, Hanh T. Nguyen

Department of Agronomy and Horticulture: Faculty Publications

• Central metabolism produces amino and fatty acids for protein and lipids that establish seed value. Biosynthesis of storage reserves occurs in multiple organelles that exchange central intermediates including two essential metabolites, malate, and pyruvate that are linked by malic enzyme. Malic enzyme can be active in multiple subcellular compartments, partitioning carbon and reducing equivalents for anabolic and catabolic requirements. Prior studies based on isotopic labeling and steady-state metabolic flux analyses indicated malic enzyme provides carbon for fatty acid biosynthesis in plants, though genetic evidence confirming this role is lacking. We hypothesized that increasing malic enzyme flux would alter carbon partitioning …

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Grassland Productivity And Water Quality: A 21st Century Issue, David M. Nash, P. M. Haygarth

IGC Proceedings (1977-2023)

1. Irrigation and other changes to the hydrological cycle can increase soil and water salinity.
2. Primary salinisation is a natural process that affects much of Europe, Asia, Africa, the Americas and Australia. Secondary salinisation is caused by human activities such as irrigation and land clearing that mobilise salt stored in the soil.
3. The critical water contaminants exported from grasslands are nitrogen, phosphorus, potential pathogens and sediment.
4. The mechanisms responsible for diffuse pollution from grasslands and mitigation strategies are most effectively investigated using a ‘source-mobilisation-transport’ framework.
5. There is a lack of coherent interaction across discipline boundaries that links pollutant sources to impact. …

Water Resources, Agriculture And Pasture: Implications Of Growing Demand And Increasing Scarcity, M. W. Rosegrant, R. A. Valmonte-Santos, S. A. Cline, C. Ringler, W. Li

IGC Proceedings (1977-2023)

1. Water availability for irrigation is threatened in many regions by rapidly increasing demand for nonagricultural water uses in industry, households, and the environment. The scarcity of irrigation water will not only impact crop production, but also meat production, as much of the pasture used to feed livestock is irrigated.
2. Grassland is caught between two countervailing forces: a requirement for increasing meat demand that boosts the need for additional pasture to support livestock production, and rapidly increasing water scarcity that makes pasture irrigation uneconomical.
3. The most effective means of dealing with water scarcity is likely to be conserving water in existing …

Soil Quality Assessment And Management, M. G. Kibblewhite

IGC Proceedings (1977-2023)

1. Soil quality is related to the capacity of soil to deliver ecosystem services on a sustainable basis.
2. Effective management of soil within grasslands can deliver many benefits to mankind but poor management may cause loss of soil quality from erosion, loss of organic matter, physical deterioration etc.
3. Services are delivered from soil by biological processes. Soil quality depends on the form and condition of the soil habitat. Fixed factors (e.g. texture) are useful for assigning soil to types. Variable factors (e.g. organic carbon) can then be used to assess quality within soil types, by reference to percentiles of the distribution …

Soil Microbial Community: Understanding The Belowground Network For Sustainable Grassland Management, Y. G. Zhu, W. D. Kong, B. D. Chen, Z. B. Nan, P. Christie

IGC Proceedings (1977-2023)

1. In addition to the use of conventional methodologies in soil microbial research, molecular techniques are now being applied to gain insights into the soil microbial community;
2. Plant diversity can exert impacts on soil microbial diversity (through root activities and plant litter etc.), but may in itself be significantly altered by soil properties;
3. Soil microbial diversity largely determines the stability of soil ecosystems under biotic and abiotic perturbations.
4. Management of soil microbial diversity can only be achieved through better understanding their structures and functions.

Grasslands1 For Production And The Environment, David R. Kemp, David L. Michalk

IGC Proceedings (1977-2023)

1. To manage grasslands for production and enhanced environmental values requires a redefinition of the frameworks within which management decisions are made, and a tailoring of practices to suit the ways that farmers operate.
2. Improving the perenniality and permanence of grasslands usually leads to better environmental and production outcomes.
3. There is a case for a more conservative approach to utilising grasslands in order to sustain the functioning of local ecosystems and to improve water quality, nutrient and energy cycling and biodiversity.
4. A landscape rather than paddock focus is more appropriate for meeting current grassland management objectives. Grasslands can be triaged to …

The Potential Of Grassland And Associated Forages To Produce Fibre, Biomass, Energy Or Other Feedstocks For Non-Food And Other Sectors: New Uses For A Global Resource, M. F. Askew

IGC Proceedings (1977-2023)

1. In developed countries increased areas of land will become available for non-food production. Recent reforms of the Common Agricultural Policy will further intensify this trend in Europe.
2. There is potential for grassland and associated species to contribute to large tonnage markets of energy and bulk fibres, to the supply of fermentation products and to speciality markets, but processes and approaches to the market are not as yet developed.
3. There is potential for the establishment of Graminaceous species - specifically for non- food use. For European conditions particular attention is being given to Miscanthus sinensis (Miscanthus), Arundo donax (Giant Reed), Phalaris …

Grasses As Biofactories: Scoping Out The Opportunities, Nick Roberts, K. Richardson, G. Bryan, Christine R. Voisey, W. Mcnabb, T. Conner, M. Christey, R. Johnson

IGC Proceedings (1977-2023)

1. Plant biopharming is set to dominate commercial recombinant protein expression for specific proteins.
2. The choice of plant species depends on a multitude of factors and is determined on a case- by-case basis.
3. As a leaf based expression system grasses would have to compete predominantly with tobacco and alfalfa.
4. The grass-endophyte symbiosis offers a number of unique possibilities for biopharming.

Adoption Of Tropical Legume Technology Around The World: Analysis Of Success, H. M. Shelton, Steven Franzel, M. Peters

IGC Proceedings (1977-2023)

1. Examples of successful adoption of forage legumes are reported from all continents, where they delivered profitability and often provided multipurpose benefits to farmers.
2. Factors vital to successful adoption were: meeting the needs of farmers; building relevant partnerships; understanding the socio-economic context and skills of farmers; participatory involvement with rural communities; and long-term involvement of champions.
3. Organisation of seed supply, achieving scale-up and forming partnerships to implement adoption are key features.
4. Legumes remain an important but under-exploited resource for tropical farming systems. The alternative to legumes will be greater and more costly use of N-fertilisers and purchased protein concentrates.
5. The R&D …

Evolution Of Integrated Crop-Livestock Production Systems, Martin H. Entz, William D. Bellotti, J. M. Powell, S. V. Angadi, W. Chen, K. H. Ominski, B. Boelt

IGC Proceedings (1977-2023)

1. Many factors contribute to changes in the crop-livestock systems, but no logical end-point in the evolution process exists.
2. While benefits of integrated crop-livestock systems over specialised crop and livestock systems are well documented, there has been a move to specialised crop and livestock production.
3. Sustainability issues (manure nutrient concentration, soil quality maintenance, salinity, herbicide resistance, economic instability) have created a renewed interest in integrated crop-livestock systems.
4. Farmer adaptability is as an important link in the evolution between ‘states of integration’.

Overcoming Seasonality Of Production: Opportunities Offered By Forage Conservation Technologies, P. O'Kiely, A. G. Kaiser

IGC Proceedings (1977-2023)

1. Seasonality of forage supply is a key contributor to the seasonality of meat and milk production.
2. Conserving forages as silage or hay can help reduce the seasonality of feed supply.
3. Forage conservation technologies make this contribution mainly through increases in the yield or quality of suitable crops, through an improved efficiency of the conservation process or by allowing a reduction in costs.
4. Future research needs differ considerably among regions of the world.

Strategies To Mitigate Seasonality Of Production In Grassland-Based Systems, Claudio Porqueddu, S. Maltoni, J. G. Mcivor

IGC Proceedings (1977-2023)

1. Fertilisation use and manipulation can cost-effectively alter species composition, increase seasonal herbage production and improve herbage quality.
2. Choice of suitable grassland species, varieties and mixtures offers opportunity to mitigate limitations of seasonal grassland production.
3. Special purpose fodder crops, cereals, shrubs and trees offer alternative or supplementary feed sources.
4. Manipulation of stocking rates, grazing systems, transhumance and pasture management at various times of the season are significant advantageous options.
5. Integration of different strategies is essential to mitigate seasonality in systems of animal production that must be inherently more sustainable over a longer time frame.

Interactions Between Foraging Behaviour Of Herbivores And Grassland Resources In The Eastern Eurasian Steppes, Deli Wang, Guodong Han, Yuguang Bai

IGC Proceedings (1977-2023)

1. In rangeland areas such as the eastern Eurasian steppes (Mongolia and China), foraging behaviour is influenced by plant or vegetation properties with high heterogeneity.
2. Until recently foraging theory has not accounted for the foraging process or ingestive behaviour. Existing theories on foraging behaviour need to evolve and begin to coalesce, and combine with observations or manipulative experiments.
3. Plant and patch properties such as diversity and height influence animal foraging behaviour (related to foraging process or diet selection) in heterogeneous steppes.
4. Stocking rate is the most important management factor for grazing or vegetation management, and determining the optimal stocking rate in …

Foraging Behaviour And Herbage Intake In The Favourable Tropics/Sub-Tropics, S. C. Da Silva, Paulo C. De F. Carvalho

IGC Proceedings (1977-2023)

1. Herbage intake by animals grazing tropical/sub-tropical pastures is directly related to bite mass, as it is for those grazing temperate pastures.
2. Where these swards have low proportions of stem and dead material (controlled swards), herbage intake follows a similar pattern to that of temperate pasture species, but leaf characteristics, such as lamina length play an important role and influence the short-term rate of intake.
3. Sward structural characteristics and behavioural factors are relatively more important than nutritional factors in terms of herbage intake regulation. The feeding value of the herbage produced is potentially adequate to sustain high levels of beef cattle …

Screening Spring Wheat Genotypes For Tadreb-B1 And Fehw3 Genes Under Severe Drought Stress At The Germination Stage Using Kasp Technology, Elsayed A. Mohamed, Asmaa A. M. Ahmed, Matías Schierenbeck, Mohamed Y. Hussein, P. Stephen Baenziger, Andreas Börner, Ahmed Sallam

Department of Agronomy and Horticulture: Faculty Publications

Drought stress is a major yield-limiting factor throughout the world in wheat (Triticum aestivum L.), causing losses of up to 80% of the total yield. The identification of factors affecting drought stress tolerance in the seedling stage is especially important to increase adaptation and accelerate the grain yield potential. In the current study, 41 spring wheat genotypes were tested for their tolerance to drought at the germination stage under two different polyethylene glycol concentrations (PEG) of 25% and 30%. For this purpose, twenty seedlings from each genotype were evaluated in triplicate with a randomized complete block design (RCBD) in …

Evaluation Of Pollination Traits Important For Hybrid Wheat Development In Great Plains Germplasm, Nicholas Garst, Vikas Belamkar, Amanda Easterly, Mary J. Guttieri, Hannah Stoll, Amir M. H. Ibrahim, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Hybrid wheat (Triticum aestivumL.) offers potential yield advantages over conventional inbred cultivars. For hybrid wheat to be a commercial success, the cost to produce the hybrid seed needs to be minimized. Although wheat is naturally selfpollinated, hybrid wheat seed production can be improved by increasing the amount and availability of pollen for cross-pollination. This research examined 19 pollination traits using the Hard Winter Wheat Association Mapping Panel for 3 years. Anther extrusion, pollen 50 date (date at which a genotype has 50% of spikes pollinating), plant height, and pollination duration (last spike pollen 50 date minus first spike …

Refined Teaching Methods, Systems Thinking, And Experiential Approaches Enhanced Students Learning Through Covid-19, Osler Ortez, Alyssa Kuhn, Meghan Sindelar

Department of Agronomy and Horticulture: Faculty Publications

The Soil Nutrient Relationships course serves juniors and seniors with a major or minor in agronomy at the University of Nebraska-Lincoln. Pre-pandemic enrollment averaged 65 students. In 2021 and 2022, course enrollment was 42 and 55, respectively. The course was adjusted to a flipped design in 2017. Moving into 2021, the Soil Nutrient Relationships course underwent a major overhaul by changing the content source materials and organization of lab activities while maintaining the flipped delivery format. While responding to the COVID-19 pandemic limitations, the redesign was intended to focus limited face-to-face meetings (in person or webconference) on problem-solving activities. This …

Jumble Judging: Cognitive And Affective Outcomes Of Intercollegiate Collaboration At A Soil Judging Competition, Rebecca A. Young, Judith Turk, Nicolas A. Jelinski, Amber D. Anderson, Kerry M. Clark, Ashlee L.D. Dere, Colby J. Moorberg, Kristopher Osterloh, Deann Presley

Department of Agronomy and Horticulture: Faculty Publications

Student–student interactions are influential parts of field experiences. While competitive judging events are a fun way to engage students in field-based learning, the focus on competition leads to an atmosphere that discourages collaboration between students. The objective of this study was to evaluate the cognitive and affective learning outcomes resulting from intercollegiate collaboration at a soil judging competition. Teams with students from two to three different universities were assigned and referred to as jumble judging teams. Jumble judging was held for the first time in the 2021 Region 5 Collegiate Soil Judging Contest. Learning outcomeswere assessed using a pre- and …

Improving The Quality Of Products From Grassland, Nigel D. Scollan, R. J. Dewhurst, A. P. Moloney, J. J. Murphy

IGC Proceedings (1977-2023)

1. Consumers are increasingly aware of the links between diet and health, and place increasing emphasis on nutritional quality as a component of product quality.
2. Meat and milk products are rich sources of nutrients such as omega-3 (n-3) fatty acids and conjugated linoleic acid, which offer health benefits to consumers.
3. Green plants are the primary source of n-3 fatty acids in the food chain.
4. Grassland production systems have the potential to enhance the content of beneficial fatty acids, improve stability (from higher antioxidant content) and alter sensory attributes of meat and milk.
5. Grassland offers considerable scope to help …

Grass And Forage Improvement: Temperate Forages, Chris J. Pollock, M. T. Abberton, M. O. Humphreys

IGC Proceedings (1977-2023)

1. Plant breeding has contributed significantly to the development of effective grassland production systems.
2. New technologies offer enhanced precision in breeding and access to wider genetic variation.
3. The requirement for more sustainable production systems will require genetic improvements in complex traits where the use of new technology will be vital.