Physical Sciences and Mathematics Commons^™

How Do Artemisia Capillaris Population Respond To Grazing Management And Rain Reduction?, Li-Yuan Shi, Fu-Jiang Hou, Zhen Wang

IGC Proceedings (1997-2023)

Climate and human activities, such as drought event and livestock grazing, generally coupled to influence the structure and function of grassland ecosystems. However, most of previous studies focused on the isolated effects of grazing or drought on grassland ecosystems, with little attention paid to the combined effects of them. Further, we know little about how plants respond to grazing and drought at the population level. We conducted a grazing regime (enclosure, stop grazing, and heavy grazing) and drought manipulation experiment in a typical steppe to explore how grassland plants response to ongoing drought and grazing regimes at the population level. …

Spring Grass Availability And Silage Supplementation Impact On Dry Matter Intake And Enteric Methane Emissions In Grazing Dairy Cattle, M. Kennedy, S. Walsh, T. M. Boland, M. Egan

IGC Proceedings (1997-2023)

Enteric methane (CH4) emissions were measured in forty spring calving cows offered one of two (n=20) contrasting diets (High Grass; HG, Low Grass; LG) over 10 weeks in early lactation (8th February – 18th April 2021). All cows were blocked for breed and parity and balanced on milk production, economic breeding index (EBI), bodyweight and body condition score and randomly allocated to treatments. The HG grazing treatment cows were offered their full daily nutrient requirement from grazed grass and concentrate with no silage supplementation. The LG grazing treatment cows were offered a restricted (~60%) amount of their daily nutrient requirement …

Forage Production Is Not Changed In Dwarf Elephantgrass Swards Managed In A Wide Range Of Pre-Grazing Canopy Heights, V. Y. M. Moncada, K. C. Vargas, D. A. Barreta, D. S. Comassetto, F. C. S. Gislon, E. R. Ribeiro, D. Moraes, A. F. Sbrissa

IGC Proceedings (1997-2023)

Height corresponding to the critical leaf area index (LAI) has been successfully used to define pre-grazing management targets in pastures subjected to intermittent stocking. However, studies on short/stoloniferous grasses have demonstrated that it is possible to manage pastures at heights below those corresponding to the critical LAI (with a threshold grazing height of approximately 65% of those corresponding to the critical LAI) and achieve a similar forage yield, provided that the severity of defoliation does not exceed 50 percent of the pre-grazing height. In this study, we hypothesized that in tall tussock grasses (such as elephant grass), the amplitude of …

Building Partnerships To Address Social And Technological Challenges To Enhance Farm Profitability And Improve Water Quality Through Better Grassland Management, C. C. Stafford, R. A. Clark, L. Ritchie, J. Dudding, G. Pent, J. Fike, J. Benner, C. Swanson, S. Baker, T. Mize, V. Temu, K. Payne, D. Gill, D. Mullins, R. Mcguire, C. Teutsch, W. Thomason, A. Grev, P. Blevins, T. P. Clarke, M. Poore, M. Booher, T. Stanley, G. Halich, J. Bovay, S. Jones, K. Love, A. Hilliard, A. Byington, E. Mullins, L. Haugen

IGC Proceedings (1997-2023)

With 2.1 million acres of pastureland and 1.25 million acres of hay land in Virginia, the rural Virginia landscape is predominately grassland. These lands form the base of the $3.96 billion-dollar livestock and dairy industry in Virginia. Managing these livestock in a profitable manner for farmers and beneficial to the environment is important. A cultural tradition with roots in colonial times has been to run animals in large fields year-round throughout Virginia. Livestock often graze from spring until fall (about 220 days), and farmers feed hay the remainder of the year. Spikes in the cost of fuel, fertilizer, and equipment …

Canopy Characteristics And Growth Rate Of Bahiagrass Monoculture And Mixtures With Rhizoma Peanut, N. Caram, Lynn E. Sollenberger, Marcelo O. Wallau, C. H. Wilson

IGC Proceedings (1997-2023)

Understanding relationships among canopy light interception (LI), canopy height and structure, and leaf area index (LAI) informs management decisions and can improve efficiency of forage-livestock systems. In a long-term experiment in Florida, USA, we assessed the LI, LAI and sward height relationships of rhizoma peanut (Arachis glabrata Benth., RP)-bahiagrass (Paspalum notatum Flügge) mixed swards compared with bahiagrass monoculture to determine whether changes in canopy structure affect herbage accumulation (HA) rate due to changes in radiation use. Treatments were arranged in a semi-factorial, split-plot design (r=4). Bahiagrass monoculture and bahiagrass-RP mixtures were whole-plot treatments. Sub-plot treatments were an undefoliated …

Influence Of Grazing On Soil Microbial Communities On A Mixed Grass Prairie Ecosystem, L. J. Ingram, G. E. Schuman, P. D. Stahl, J. Buyer

IGC Proceedings (1997-2023)

The grazing of ungulates is the predominant use for much of the world's semiarid rangelands. Grazing these lands can result in significant changes not only in the vegetation community but also in the soil physical, chemical and biological properties. Changes in soil physical and chemical properties and the plant community can potentially lead to changes in soil microbial communities which may have long-term ramifications for nutrient cycling and carbon (C) sequestration. The objective of this research was to ascertain the influence of three long-term grazing treatments on soil microbial communities.

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

IGC Proceedings (1997-2023)

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 …

External Validation In Northwest Spain Of A Decision Support System For Grazing Dairy Cows (Grazemore), Antonio González-Rodríguez, J. López Díaz, O. P. Vázquez Yáñez

IGC Proceedings (1997-2023)

A model to predict intake and milk production of cows on grazed grass (Grazemore) was developed (Mayne et al., 2004) for farmers to increase reliance on the grassland resources of the farm and reduce the tendency towards intensive dairy production in most countries of the Atlantic Arc of Europe (González, 2003). Climatic conditions and fertiliser use is the basis of the herbage growth model, but under practical conditions the estimation of the nutrient supply to cows is much affected by management, number of cows and the area of each paddock grazed. The intake capacity of the animal and the …

Determination Of Optimal Grazing Management For Dairy Cows In Galicia (Spain) Using A Decision Support System, O. P. Vázquez Yáñez, A. González Rodríguez, J. López Díaz

IGC Proceedings (1997-2023)

GRAZEMORE is a decision support system (DSS) oriented to evaluate dairy grazing management decisions on pasture growth and milk production. The system integrates a herbage growth model (Barrett et al., 2003) and a herbage intake model (Delagarde et al., 2004) and has been validated in several EU countries. The objective of this work was to use this DSS to determine optimal grazing management of dairy cows at three supplementation levels and three grazing management strategies under Galician conditions.

Grassland Technology Interaction And Policy Evolution In Canada, Duane H. Mccartney, P. Jefferson

IGC Proceedings (1997-2023)

Canada is the world's second largest country covering approximately 10 million km² (McCartney & Horton, 1997). About 90% of Canada is uninhabited with 90 percent of Canadians living within 500 km of the American border. The forage resources used by livestock grazing and the production of forage crops covers over 36 million ha of Canada's land base (3.6%) and is divided into 72% native range (26 million ha), 11% cultivated pastures (4 million ha) and 17% forage crops (6 million ha) There are 25 million ha in grain and oilseed crops (McCartney & Horton, 1997).

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 (1997-2023)

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).

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

IGC Proceedings (1997-2023)

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.

Sustainable Semi-Arid Grazing Management Based On Indigenous Shona Practices Prior To Introduction Of Western Ideas In Zimbabwe, O. Mugweni, R. Mugweni

IGC Proceedings (1997-2023)

In the Shona culture the land, i.e. the plants, animals, soil, water, air and others, evolved with herding animals. Hence, the absence of one results in the destruction of the other. It is argued that the conventional grazing management belief that too many animals cause overgrazing is a misconception of the semi-arid savanna environments of Southern Africa where these environments evolved with thousands of herding grazers and mega-faunas such as elephants, wildebeests and buffalo. The objective of the research is to establish that grazing with an adequate recovery period for grazed plants, as a result of domesticated animals being managed …

Herbage Production Of Tanzania Grass (Panicum Maximum Cv. Tanzania) Submitted To Combinations Of Frequencies And Intensities Of Grazing By Cattle, Domicio Nascimento Jr., Rodrigo A. Barbosa, Valéria P. B. Euclides, S. C. Da Silva, R. A. Torres

IGC Proceedings (1997-2023)

Animal production from pastures is a complex process comprising three main stages: herbage growth, consumption by grazing animals and conversion into animal products (Hodgson, 1990). Utilisation is the stage where the grazier finds greater flexibility for management, probably because most processes related to harvest of the produced herbage by the grazing animals are very responsive to manipulation and control of defoliation practices. The objective of this study was to evaluate herbage production of a Panicum maximum cv. Tanzania pasture submitted to combinations of frequencies and intensities of grazing.

Herbage Intake And Animal Performance Of Cattle Grazing Brachiaria Brizantha Cv. Marandu Under Continuous Stocking, S. C. Da Silva, P. Sarmento, L. K. Molan, F. M. E. Andrade, André F. Sbrissia, A. V. Lupinacci, A. C. Gonçalves, D. E. Oliveira

IGC Proceedings (1997-2023)

Grazing management affects sward structure, which in turn influences plant and animal responses. With the objective of understanding causal relationship between sward structure and animal responses, the present experiment evaluated the daily herbage intake and live weight gain of growing cattle on Brachiaria brizantha cv. Marandu pasture during summer (Dec. 2001 to Mar. 2002).

Sustainable Semi-Arid Grazing Management Based On Indigenous Shona Practices Prior To Introduction Of Western Ideas In Zimbabwe, O. Mugweni, R. Mugweni

IGC Proceedings (1997-2023)

In the Shona culture the land, i.e. the plants, animals, soil, water, air and others, evolved with herding animals. Hence, the absence of one results in the destruction of the other. It is argued that the conventional grazing management belief that too many animals cause overgrazing is a misconception of the semi-arid savanna environments of Southern Africa where these environments evolved with thousands of herding grazers and mega-faunas such as elephants, wildebeests and buffalo. The objective of the research is to establish that grazing with an adequate recovery period for grazed plants, as a result of domesticated animals being managed …

Rangeland As A Common Property Resource: Contrasting Insights From Communal Areas Of Central Eastern Cape Province, South Africa, J. E. Bennett, H. R. Barrett

IGC Proceedings (1997-2023)

In communal areas of South Africa, grazing systems are held under a variety of different common property regimes. However, the social and ecological realities of these communal grazing systems remain poorly understood, particularly with regard to the use of land allocated for crop production. Little is known about how these arable areas are utilised as a common grazing resource but the wide array of tenure arrangements under which they are held suggests that they facilitate some interesting departures from recognised common property systems. A clearer understanding of how common property regimes function at an integrated level in South Africa will …

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

IGC Proceedings (1997-2023)

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 (1997-2023)

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, …

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 (1997-2023)

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 (1997-2023)

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.

Both Grass Development Stage And Grazing Management Influence Milk Terpene Content, G. Tornambé, A. Cornu, N. Kondjoyan, P. Pradel, M. Petit, B. Martin

IGC Proceedings (1997-2023)

Terpenes are a wide group of molecules originating from plants’ secondary metabolism. Forage terpenes vary according to the botanical composition and in particular to the proportion of plants such as Apiaceae, Lamiaceae or Asteraceae. These molecules are considered effective milk markers for the presence of diversified forages in dairy cow diets. The variation in terpene content in the milk of grazing cows would depend on the period of development of terpene-rich plants and on the grazing management, whereby cows do or do not have the opportunity to choose and to modify the botanical composition of the ingested grass. The aim …

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

IGC Proceedings (1997-2023)

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 …

Challenges And Opportunities For Sustainable Rangeland Pastoral Systems In The Edwards Plateau Of Texas, J. W. Walker, J. L. Johnson, C. A. Taylor Jr.

IGC Proceedings (1997-2023)

This paper focuses on pastoral systems in an area of west-central Texas known as the Edwards Plateau. These rangelands have a combination of grass, forb and browse species and are used primarily for combinations of grazing by cattle, sheep, goats and wildlife. A major ecological challenge is woody plant encroachment. Stocking rate is the major factor affecting sustainability and historically this area was heavily grazed. Today the stocking rate is half or less of its historical peak. Species of livestock has shifted from predominantly small ruminant to cattle. About 70 % of pastoralists use some sort of rotational grazing system. …

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

IGC Proceedings (1997-2023)

Key points

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 …

Spring Forage Stash Module To Prevent Forage Crisis On Uruguayan Livestock Systems: An Evaluation Based On Model Simulations, M. Pereira Machín, F. Dieguez Cameroni

IGC Proceedings (1997-2023)

In Uruguay, rangeland cattle production systems support national economy by beef exportation chain and economic inputs to the country. Soil hydric stress episodes results to forage crisis on grassland-based production systems, having high impact on its trajectory and leaving sequels at several farm levels mainly on rearing cattle systems in drought sensitive regions of the country. In that context, the proposal is to create a spring forage stash module, with a simple management rules as a mechanism to build stability to farms and to buffering drought impact. The concept is to differ spring forage (season with low variation coefficient on …

Real-World Applications For Virtual Fences – What Are Potential Benefits For Conservation?, F. Riesch, M. Komainda, J. Horn, J. Isselstein

IGC Proceedings (1997-2023)

Livestock grazing can enhance biodiversity and ecosystem services in agricultural landscapes. In many parts of Europe, however, grazing has lost its importance, especially in the dairy sector. Large proportions of permanent grassland have been converted to arable land or intensified by fertilization and frequent defoliation. The disappearance of large herbivores and extensively grazed pastures contributes to the loss of structural, functional and biological diversity and ecosystem services. Modern technologies, which circumvent the cost- and labour-intensive installation of physical fences, could facilitate a precise spatio-temporal management of livestock and promote grazing. We reviewed the literature on the state-of-the-art of virtual fencing, …

Effect Of High-Intensity, Short-Duration Grazing On Species Density And Botanical Composition Of Arid Rangelands, Mounir Louhaichi, Mouldi Gamoun, Fethi Gouhis, Ezzeddine Belfekih, Mohamed Abdelkader

IGC Proceedings (1997-2023)

Rangelands are the mainstay of pastoral and agropastoral livelihoods worldwide. They have provided forage for livestock and wildlife for centuries, but steady degradation of rangelands is causing increasing concern. Many rangeland managers believe exclusion of livestock grazing for extended periods would allow degraded rangelands to recover. The purpose of this current ongoing research is to evaluate the effect of high-intensity short-duration grazing on plant density, species richness and botanical composition on arid rangelands during favorable years. The site, which is protected for two years in southern Tunisia and covers an area of 6 ha, was grazed by a flock of …

Impact Of Grazing Management On Productivity Of Tropical Grasslands, Moacyr Corsi, Geraldo B. Martha Jr., Domício Do Nascimento Jr., Marco A. A. Balsalobre

IGC Proceedings (1997-2023)

Beef and dairy cattle enterprises from tropical pasture-based systems are notoriously of low productivity. The low soil fertility, the exploitation of native grasslands, the low genetic potential of the animals and the poor management of soil, pasture and animal components are all arguments used to explain these “low-productivity systems”. In fact, research has consistently indicated up to 50% increase in calving rate when animals grazing unfertilized pastures were supplemented with trace-mineralized salt (Table 1) but unfortunately less than 90% of Brazilian farmers use this management strategy (Tosi, 1997). However, a recent survey conducted by São Paulo State government showed that …

Impact Of Grazing Management On The Productivity Of Cold Temperate Grasslands Of Southern Patagonia - A Critical Assessment, A. F. Cibils, M. B. Coughenour

IGC Proceedings (1997-2023)

The contention that productivity of cold temperate grasslands of southern Patagonia have been greatly affected by domestic herbivore grazing in the past is fairly widespread. The consequences of spatiotemporal interactions between grazing and abiotic factors on the overall productivity of such systems, however, are still poorly understood. Predictions of both short- and long-term impacts of grazing management strategies on grassland productivity require a better understanding of these interactions. In this paper we make a critical assessment of the impact of grazing management on long-term sustainability of the grass steppes of southern Patagonia (Argentina). We discuss this issue in the context …