Life Sciences Commons^™

A New Agro-Meteorological Simulation Model For Predicting Daily Grass Growth Rates Across Ireland, R. P. O. Schulte

IGC Proceedings (1977-2023)

Grass growth rates and herbage yields depend on weather conditions, soil characteristics and grassland management and differ from year to year and from site to site. In the past, grass growth has been predicted using both mechanistic and statistical models. The accuracy of mechanistic models is commonly insufficient for practical application, while statistical models generally apply to one test site only (e.g. Han et al., 2003). In this paper a semi-empirical grass growth model is presented which is numerically accurate, but which can be applied to contrasting sites across Ireland at the same time.

A Farmer-Based Decision Support System For Managing Pasture Quality On Hill Country, I. M. Brookes, D. I. Gray

IGC Proceedings (1977-2023)

Despite considerable effort to promote formal feed budgeting in New Zealand, survey data suggests it is only adopted by 20% of farmers (Nuthall & Bishop-Hurley, 1999). Recent work (Gray et al., 2003) has identified that farmers may use a different approach - micro-budgeting - to manage feed. Rather than operate at a whole farm level, micro-budgeting focuses at the paddock level. This paper describes micro-budgeting as used by a high performing hill country sheep and cattle farmer to manage pasture quality over spring and a decision support model developed to help other farmers undertake this process

Pâtur’In: A User-Friendly Software Tool To Assist Dairy Cow Grazing Management, L. Delaby, J. L. Peyraud, P. Faverdin

IGC Proceedings (1977-2023)

The feeding of dairy cows at pasture presents many technical, economic and environmental advantages, while benefiting from a very favourable image. However, the management of grazed land is a complex game of strategy in which the farmer applies decisions in order to manage two unstable and uncertain fluxes of change: growth of grass and intake of the herd. Many tools (platemeter, etc.) and overall methods (local stocking rate references, farm cover, etc.) have been developed as aids to grazing management. Nevertheless, few decision-support systems are currently available that make it possible to anticipate and assess the consequences of a given …

Understanding Livestock Grazing Impacts: A Decision Support Tool To Develop Goal-Oriented Grazing Management Strategies, S. J. Barry, K. Guenther, G. Hayes, R. Larson, G. Nader, M. Doran

IGC Proceedings (1977-2023)

Managing grasslands in the western United States has become much more complex over the last few decades. A century ago the goal was to survive as a livestock producer, and grassland management involved using forage effectively and overcoming obstacles such as predators and shortages of water and feed. Today the successful grassland manager also needs to consider the diversity and health of the ecosystem as a whole. Livestock grazing can negatively and/or positively affect riparian areas, sensitive plants, and endangered wildlife. Since the impact on a specific factor will vary depending on the timing, intensity and class of livestock grazed, …

Enhancing Grasslands Education With Decision Support Tools, H. G. Daily, J. M. Scott, J. M. Reid

IGC Proceedings (1977-2023)

We have successfully used Decision Support Tools (DST) relevant to the management of grazing enterprises to enhance problem solving skills of undergraduates in Australia. Tools such as GrassGro™ (Moore et al., 1997) and GrazFeed™ (Freer et al., 1997) are accessed from a central server by authorised users at many widely dispersed Universities across Australia using remote access to thin-client technology via an Internet portal. This has been supplemented with training for lecturers. Experience in developing appropriate teaching and learning materials and the reliable delivery of simulation software to many clients has enhanced learning outcomes at tertiary level. We …

A Farmer Friendly Feed Budget Calculator For Grazing Management Decisions In Winter And Spring, M. Curnow, M. W. Hyder

IGC Proceedings (1977-2023)

The Western Australian (WA) environment is Mediterranean with annual legume/grass pastures and a 6 month growing season. In autumn where over grazing can impact pasture establishment and in spring, prior to senescence, when under grazing can mean significant losses of efficiency are crucial times for grazing management. Pasture utilisation is typically low (25-35%) due to conservative stocking regimes; key to increasing productivity is increasing pasture utilisation (Grimm, 1998). Increased levels of productivity require farmer sophistication in the way they feed budget. To this end, satellite technology is being used to provide farmers in southern Australia with weekly estimates of pasture …

Simulation Of Pasture Phase Options For Mixed Livestock And Cropping Enterprises, L. Salmon, A. D. Moore, J. F. Angus

IGC Proceedings (1977-2023)

In southern Australia, 50% of grain-producing farms also run beef and/or sheep enterprises. Legume pasture leys are used to replace soil nitrogen and manage crop disease risks. Deep-rooted perennials, predominantly lucerne (Medicago sativa), are replacing annual Trifolium subterraneum-based leys to increase pasture production. They also have the environmental benefits of limiting soil acidity, rising water tables and dryland salinity. After recent droughts depletion of soil water by lucerne has penalised wheat yields. Decision support tools can help farmers evaluate the long-term effects of grazed annual and perennial leys on animal and crop production at the whole farm …

Grasscheck: Monitoring And Predicting Grass Production In Northern Ireland, P. D. Barrett, A. S. Laidlaw

IGC Proceedings (1977-2023)

No abstract provided.

Effect Of Strategy Of Forage Supplementation And Of Turnout Date In A Medium Stocking Rate System On The Main Characteristics Of Dairy Cows Grazing, P. Defrance, L. Delaby, J. M. Seuret, M. O'Donovan

IGC Proceedings (1977-2023)

Having a stocking rate of 2.9 cows per hectare of grassland (35 ares/cow) in Brittany offers many options for turnout date and forage supplementation strategies. For a farmer, knowing the consequences of the different options during the course of the grazing season makes grazing management decisions easier. As experiments on grazing management require considerable resources and are hardly generalisable, various spring scenarios have been tested using a dynamic decision support system, Pâtur’IN (Delaby et al., this volume).

Grass Growth Profiles In Brittany, P. Defrance, J. M. Seuret, L. Delaby

IGC Proceedings (1977-2023)

For farmers, knowing the local grass growth profile and the possible variations between years is very helpful in managing grazing. Indeed, the comparison with herd needs and anticipated farm cover change allows decisions to be made that will maintain the cover at the desired level. This paper proposes a ten-days grass growth profile corresponding to Brittany’s different conditions of soil, climate and pasture management.

Using The Grassgro Decision Support Tool To Evaluate The Response In Grazing Systems To Pasture Legume Or A Grass Cultivar With Improved Nutritive Value, H. Dove, J. R. Donnelly

IGC Proceedings (1977-2023)

Decision support tools (DST) based on models of grazing systems allow the evaluation of changes in enterprise management on productivity and profitability. The Grassgro DST (Moore et al., 1997) uses historical weather data on a daily time step to simulate pasture growth and the resultant productivity of either grazing sheep or cattle. Different pasture species are represented within a parameter set that describes the response of pasture species to their environment. Manipulation of these parameters provides a means of evaluating, a priori, the likely responses of livestock production to ‘improved cultivars’. We report the results of simulations conducted …

Factors Affecting Presence And Occupancy Of Marabou Storks (Leptoptilos Crumeniferus) At Abattoirs And Slaughter Slabs Near Jinja, Uganda, Elena Arroway

DU Undergraduate Research Journal Archive

This study examined the factors affecting the presence and occupancy of marabou storks at abattoirs and slaughter slabs near Jinja, Uganda. The average number of storks per unit area was compared across different areas within one large abattoir, including an analysis of the presence of free food, human disturbance, and other scavenging birds (pied crow, piapiac, spur-winged lapwing, and cattle egrets). Occupancy across two abattoirs and one slaughter slab was compared and related to the number of animals slaughtered daily at the facility. Direct observations at abattoirs and slaughter slabs were conducted for ten minutes with five minutes between observations. …

Increased Floodplain Inundation In The Amazon Since 1980, Ayan Fleischmann, Fabrice Papa, Stephen K. Hamilton, Alice Fassoni-Andrade, Sly Wongchuig, Jhan Carlo Espinoza, Rodrigo Paiva, John Melack, Etienne Fluet-Chouinard, Rafael M. Almeida

School of Earth, Environmental, & Marine Sciences Faculty Publications

Extensive floodplains throughout the Amazon basin support important ecosystem services and influence global water and carbon cycles. A recent change in the hydroclimatic regime of the region, with increased rainfall in the northern portions of the basin, has produced record-breaking high water levels on the Amazon River mainstem. Yet, the implications for the magnitude and duration of floodplain inundation across the basin remain unknown. Here we leverage state-of-the-art hydrological models, supported by in situ and remote sensing observations, to show that the maximum annual inundation extent along the central Amazon increased by 26% since 1980. We further reveal increased flood …

Feasibility Of [18f]Fspg Pet For Early Response Assessment To Combined Blockade Of Egfr And Glutamine Metabolism In Wild-Type Kras Colorectal Cancer, Seong-Woo Bae, Jianbo Wang, Dimitra K Georgiou, Xiaoxia Wen, Allison S Cohen, Ling Geng, Mohammed Noor Tantawy, H Charles Manning

Faculty, Staff and Student Publications

Early response assessment is critical for personalizing cancer therapy. Emerging therapeutic regimens with encouraging results in the wild-type (WT) KRAS colorectal cancer (CRC) setting include inhibitors of epidermal growth factor receptor (EGFR) and glutaminolysis. Towards predicting clinical outcome, this preclinical study evaluated non-invasive positron emission tomography (PET) with (4S)-4-(3-[18F]fluoropropyl)-L-glutamic acid ([18F]FSPG) in treatment-sensitive and treatment-resistant WT KRAS CRC patient-derived xenografts (PDXs). Tumor-bearing mice were imaged with [18F]FSPG PET before and one week following the initiation of treatment with either EGFR-targeted monoclonal antibody (mAb) therapy, glutaminase inhibitor therapy, or the combination. Imaging was correlated with tumor volume and histology. In PDX …

Data From: Mechanisms Of Gill-Clogging By Hagfish Slime, Luke Taylor, Gaurav Chaudhary, Gaurav Jain, Andrew Lowe, Andre Hupe, Atsuko Negishi, Yu Zeng, Randy Ewoldt, Douglas Fudge

Biology, Chemistry, and Environmental Sciences Faculty Data Sets

Abstract of Proc. Roy. Soc. article:

Hagfishes defend themselves from gill-breathing predators by producing large volumes of fibrous slime when attacked. The slime’s effectiveness comes from its ability to clog predators’ gills, but the mechanisms by which hagfish slime clogs are uncertain, especially given its remarkably dilute concentration of solids. We quantified the clogging performance of hagfish slime over a range of concentrations, measured the contributions of its mucous and thread components, and measured the effect of turbulent mixing on clogging. To assess the porous structure of hagfish slime, we used a custom device to measure its Darcy permeability. We …

Ergot And Sterility In Bahiagrass: Genotypic And Environmental Effects On Seed Yield Potential, Javier Do Canto, Rafael Reyno, Hector Oberti, Marco Dalla Rizza, Daniel Real

Grain and Other Field Crops Research Articles

Ergot disease (Claviceps paspali) and sterility have the potential to reduce seed yield in bahiagrass (Paspalum notatum Flüggé). Our objective was to determine the genotypic and environmental effects on seed yield, and the levels of ergot and sterility. Seventeen genotypes were evaluated in three locations across two years for seed yield, ergot severity, and total seed fractions (percentage of full seeds, ergot sclerotia and empty seeds). The percentage of full seeds and total seed yield were correlated (r = 0.52) but both were negatively correlated with the percentage of ergot sclerotia (r = −0.81 and −0.51). …

Monitoring Resistance And Biochemical Studies Of Three Egyptian Field Strains Of Spodoptera Littoralis (Lepidoptera: Noctuidae) To Six Insecticides, Moataz A M Moustafa, Rasha I A Moteleb, Yehia F Ghoneim, Sameh Sh Hafez, Reham E Ali, Essam E A Eweis, Nancy N Hassan

Faculty, Staff and Student Publications

BACKGROUND:

METHODS: Laboratory bioassays were carried out using the leaf-dipping method to examine the susceptibility of the laboratory and field strains to the tested insecticides. Activities of detoxification enzymes were determined in an attempt to identify resistance mechanisms.

RESULTS: The results showed that LC

CONCLUSION: Our findings, along with other tactics, are expected to help with the resistance management of

Pasture Land Management System Decision Support Software, G. E. Groover, S. R. Smith, N. D. Stone, J. J. Venuto, J. M. Galbraith

IGC Proceedings (1977-2023)

Controlled or rotational grazing provides benefits to producers and society through profitable and sound management of grazing land and livestock. Pasture land management system (PLMS) is a decision support system developed to help university, government, and professionals provide technical pasture management assistance to beef and dairy producers. The PLMS focuses on the balance between seasonal forage supply and nutrient demand in a dairy or beef cattle operation. It allows users to explore and compare alternatives (dividing fields into multiple paddocks, changing stocking rates, and forage species) through a visual display and embedded simulation. Users enter a description of the farm …

Forecast Of Herbage Production Under Continuous Grazing, K. Søegaard, J. Berntsen, K. A. Nielsen, I. Thysen

IGC Proceedings (1977-2023)

The utilization of pasture is very sensitive to oscillations in herbage growth. The farmer’s daily planning involves decisions on pasture use as well as on the amount and composition of supplement feeding. In this planning, expected daily growth rate is an important factor. Often the knowledge and experience about the growth rate is first available after changes in management should have been made. A different growth rate than expected should lead to changes in the grazing area or in the supplement feeding. Therefore, a simple model of grass/clover growth under grazing and irrigated conditions was developed. From spring 2004, the …

A Decision Support Tool For Seed Mixture Calculations, B. P. Berg, G. Hutton

IGC Proceedings (1977-2023)

Grassland species are normally seeded in mixtures rather than monocultures. In theory, seeding rates for mixtures are simply a sum of the amount of pure live seed (PLS) of each seed lot in the mix, an amount sufficient to ensure establishment and survival of each species. Mixtures can be complex because of the number of species used (especially in conservation and reclamation programs) and variations in seed purity and seed size. Soil limitations and seeding equipment settings need to be considered and in Canada, a metric conversion may be required. All these conditions make by-hand calculations of mixtures containing more …

Risk-Efficiency Assessment Of Haying, A. J. Romera, J. Hodgson, S. T. Morris, S. J. R. Woodward, W. D. Stirling

IGC Proceedings (1977-2023)

Pastoral livestock farms are complex, dynamic systems subject to many forms of external disturbance. Farm Management strategies are therefore typically designed to minimize system variation. The objective of this study was to explore the impacts of different haying policies, in terms of expected profit and risk, for cow-calf farms in the Salado Region of Argentina.

Environmental Clustering Of New Zealand Dairy Herds, J. R. Bryant, N. López-Villalobos, J. E. Pryce, C. W. Holmes

IGC Proceedings (1977-2023)

Previous studies have found that milk yield (a proxy for feeding level) and temperature-humidity index (THI) are important factors in explaining genotype x environment (G x E) interactions, indicating differences between the abilities of genotypes to forage or consume concentrates effectively or to cope with thermal stress (Ravagnolo and Misztal, 2000; Zwald et al., 2003). The objective of this study was to quantify and cluster (CL) herd environments within New Zealand (NZ) based on production levels, a summer heat load index (HLI) and geographical location.

Irish Dairy Farming: Effects Of Introducing A Maize Component On Grassland Management Over The Next 50 Years, A. J. Brereton, N. M. Holden

IGC Proceedings (1977-2023)

Typical management of Irish dairy units is based on a low-cost spring-calving strategy with 90% of annual feed derived from grass grown on the farm. Almost 70% of feed is from grazed grass managed by rotational grazing, the remainder is conserved forage and concentrates. The objectives of the work were to examine how the management system has to be modified when part of the dairy unit land is allocated to maize silage instead of grass silage production, and to examine how climate change over the next 50 years will impact on grass and maize management within the production system.

Autumn Root Reserves Of Lucerne Affected Shoot Yields During The Following Spring, D. J. Moot, E. I. Teixeira

IGC Proceedings (1977-2023)

Frequent grazing affects shoot yield of lucerne (Medicago sativa L.) by limiting radiation interception (Teixeira et al., 2005b) and the accumulation of endogenous reserves (C and N) in perennial storage organs like crowns and taproots (Teixeira et al., 2005a). In temperate regions, the impact of low level of perennial reserves is particularly evident during early-spring, when lucerne regrowth resumes after an overwintering period. The analysis of lucerne yield can be fragmented into its yield components of plant population, shoots per plant and yield per shoot (Volenec et al., 1987). The objective of this research was to quantify …

Lucerne Crown And Taproot Biomass Affected Early-Spring Canopy Expansion, E. I. Teixeira, D. J. Moot, A. L. Fletcher

IGC Proceedings (1977-2023)

Leaf area index (LAI) quantifies canopy expansion in crops and is used in lucerne (Medicago sativa L.) simulation models to predict daily PAR interception (PAR i). This then drives yield through radiation use efficiency (RUE) (Gosse et al., 1984). In perennial crops, like lucerne, the level of biomass stored in crown and taproot may affect canopy expansion in subsequent regrowth cycles (Avice et al., 1997). In temperate regions the impact of this is likely to be greatest in early-spring, when low temperatures delay development. The objective of the current research was to identify whether contrasting levels of winter biomass in …

Extending The Grazing Season With Turnips, P. Thomet, S. Kohler

IGC Proceedings (1977-2023)

A comparison of the actual feeding costs on 86 typical Swiss dairy farms confirmed that the production of hay and grass silage is very expensive with costs from the field to intake in the range of 20-25 Euro cents/kg of dry matter (DM). Options to extend the grazing season for dairy cows in the late autumn and early winter, and hence reduce winter feeding costs, would therefore be welcome (Penrose et al., 1996). The aim of the study was to compare the DM production potential of summer-seeded turnips with other brassicas and Italian ryegrass and to test whether dairy cows …

Milk Production Performance Based On Grazed Grassland In Switzerland, P. Thomet, H. Menzi

IGC Proceedings (1977-2023)

A common feature of profitable dairy systems is the use of large amounts of low cost feed. One approach to improve the competitive ability of the dairy production therefore is to promote grazing (Dillon et al., 1995). A comparison of the actual feeding costs on typical Swiss dairy farms showed that hay and grass silage were four times and concentrates seven times more expensive than grazed grass. A maximum utilisation of grazed grass can be achieved with a seasonal production system, which synchronises the cow’s feed requirements with pasture growth. This strategy was implemented and consistently optimised on an …

The Effect Of Inclusion Of A Range Of Supplementary Feeds On Herbage Intake, Total Dry Matter Intake And Substitution Rate In Grazing Dairy Cows, S. J. Morrison, D. C. Patterson, S. Dawson, C. P. Ferris

IGC Proceedings (1977-2023)

The milk production potential of dairy cows has increased substantially over the past two decades. This development presents new challenges for managing dairy cows during grazing, particularly where the objective is to maximise the proportion of energy in the diet derived from forage. The objective of the current study was to explore supplementation strategies to maintain high total forage intakes from grazed grass supplemented with alternative forage supplements in dairy cows during the grazing season. A second objective of the study was to examine the effect of supplement on substitution rate (SR) and milk yield response.

White Clover Soil Fatigue: An Establishment Problem On Large And Intensive Dairy Farms, K. Søegaard, K. Møller

IGC Proceedings (1977-2023)

In recent years a new constraint, clover soil fatigue, has appeared for the establishment of white clover (Trifolium repens) in Denmark. Increasing dairy farm size has led to more intensive use of clover in crop rotation schemes in the grazing areas located at convenient distances from stables. It has become common practice to establish new clover/grass in the fields just after ploughing clover/grass swards, and soil fatigue is becoming more common. On fatigued land the clover plants emerge, then become stunted and eventually disappear within the same year. The problem tends to cover the full field area. Obviously, …

Effect Of Farm Grass Cover At Turnout On The Grazing Management Of Spring Calving Dairy Cows, M. O'Donovan, L. Delaby, P. Defrance

IGC Proceedings (1977-2023)

Early spring grazing is an objective for most Irish dairy farmers. If more grass is included in the diet of the cow in early lactation, the profitability of the farm system can be increased. Post turnout, dairy cow feeding management varies with the amount of farm grass cover (FC) available. Experiments on the consequences of different FC at turnout require large resources and all scenarios cannot be accounted for. Consequently, a decision support system, Pâtur’IN (Delaby et al., this volume), was used to describe the effects of various FC at turnout on grazing management in spring.