Agronomy and Crop Sciences Commons^™

Ingestive Behaviour Of Steers In Native Pastures In Southern Brazil, C. E. Pinto, Paulo C. De F. Carvalho, A. Frizzo, J. A.S.F. Júnior, T. M. S. Freitas, Carlos Nabinger

International Grassland Congress Proceedings

The Campos biome, particularly its native pastures, is the main resource for livestock production in southern Brazil (Boldrini, 1997). It has a huge floristic diversity in which more than 400 grass and 150 legume species are found. These pastures are very heterogeneous with horizontal as well as vertical structure. Hodgson (1985) stressed the importance of sward structure upon diet selection, emphasizing the difficulties animals could have to access all pasture layers in temperate pastures. This experiment investigates how variation in herbage allowance along the growing season influences the ingestive behaviour of steers.

The Efficacy Of Genethresher® Methylation Filtering Technology In The Plant Kingdom, U. Warek, J. A. Bedell, M. A. Budiman, A. N. Nunberg, R. W. Citek, D. Robbins, N. Lakey, P. D. Rabinowicz

International Grassland Congress Proceedings

The genomes of many plants are known to be composed of a large fraction of repetitive DNA, while a small portion is dedicated to genes. The bulk of the repetitive DNA constitutes transposable elements and is heavily methylated. GeneThresher technology has been developed to take advantage of these differential methylation patterns by filtering genomic shotgun libraries to exclude methylated sequences (Rabinowicz et al., 1999; Palmer et al., 2003; Martienssen et al., 2004). The result is a gene-enriched genomic shotgun library. Random shotgun sequencing of plant gene space, enabled by GeneThresher technology, is a rapid and cost-effective strategy …

Translational Genomics For Alfalfa Varietal Improvement, G. D. May

International Grassland Congress Proceedings

Key points

1. Medicago truncatula is a model legume with available mapping, genome, and RNA, protein and metabolite profiling databases and genetically diverse populations.
2. Genomics resources developed for M. truncatula have application in the study and improvement of alfalfa making it an excellent model for this forage legume.

Species Richness Affects Grassland Yield And Yield Stability Across Seasons, Sites And Years, David J. Barker, Reuben M. Sulc, M. R. Burgess, T. L. Bultemeier

International Grassland Congress Proceedings

The benefits of biodiversity (specifically species richness) are proposed to include both greater yield and greater stability of yield in a variable environment (Sanderson et al., 2004). Experimental evidence showing yield benefits is inconsistent (White et al., 2004). There is relatively little experimental data showing the effects of species richness on yield stability. The objective of this study was to measure the yield from mixtures with up to 12 species, and to measure the variability of yield between 2 sites, between spring and summer, and in 2 successive years.

Discovery And Functional Categorisation Of Expressed Sequence Tags From Flowers Of Eragrostis Curvula Genotypes Showing Different Ploidy Levels And Reproductive Modes, V. Echenique, S. Felitti, N. Paniego, L. Martelotto, S. C. Pessino, D. Zanazzi, P. Fernández, M. Díaz, P. Polci, G. C. Spangenberg

International Grassland Congress Proceedings

Two novel genotypes of weeping lovegrass (Eragrostis curvula) - a dihaploid strain obtained in vitro from an apomictic cultivar and a tetraploid plant derived from the dihaploid after chromosome duplication – have recently been developed. These materials represent an excellent system for the identification, through transcriptional profiling, of genes involved in diplospory and/or ploidy level gene regulation. The aim of this work was the discovery and functional classification of expressed sequence tags (ESTs) from immature inflorescences of the apomictic E. curvula cultivar Tanganyika (2n=4x=40), a dihaploid sexual strain derived from it (2n=2x=20) and a tetraploid sexual strain …

Protection Of Agrobiodiversity: Model Calculations In Rhineland-Palatia: Costs And Implications For Farmers, H. Bergmann

International Grassland Congress Proceedings

Biological conservation and production use the same areas of land in less favoured areas. Grassland in these areas makes an important contribution to the protection of agro-biodiversity. However, under existing market conditions and production needs, the use of low yielding grasslands is not economically efficient. The objective of this study was to analyze the economic consequences of different mowing strategies in a small region in Rhineland-Palatia (Germany) that served the protection of two butterfly species.

Stocking Rate Theory And Profit Drivers In North Australian Rangeland Grazing Enterprises, Neil D. Macleod, A. J. Ash, John G. Mcivor

International Grassland Congress Proceedings

Setting correct stock numbers is a key decision for successful pastoralism. In marginal environments, typified by northern Australia, this involves careful cattle herd management across landscapes and seasons characterised by heterogeneous land condition and extreme climatic uncertainty. Stocking rate theory which links animal production to stocking rates concentrates only on liveweight gain of sale animals and ignores complex herd (e.g. reproduction, mortality) and pasture dynamics (e.g. land condition) and costs of maintaining stock numbers (e.g. supplementary feeding). Related economic models are generally naïve and incomplete, being based on liveweight gain, meat prices and variable husbandry costs (e.g. Workman, 1986). Modelling …

An Ecological And Economic Risk Avoidance Drought Management Decision Support System, R. K. Heitschmidt, L. T. Vermeire

International Grassland Congress Proceedings

Ecologists have long recognized the fundamental impacts of drought on rangeland structure and function. Simulation models have been developed to increase our understanding of these impacts as they relate to forage production, particularly for predictive purposes. Although the capacity of these models to accurately predict quantity and quality of forage produced under varying climatic conditions is often quite good, their ability to serve as an effective and proactive drought management decision support system is often limited. This is in large part because their complexity impedes their use by on-the-ground managers. The objective of this research was to develop a very …

Predicting The Effects Of Management On Upland Birds, Economy And Employment, S. M. Gardner, G. M. Buchanan, J. W. Pearce-Higgins, M. C. Grant, A. Waterhouse

International Grassland Congress Proceedings

Livestock farming systems play a significant role in the economy and conservation of the UK uplands and rely heavily upon public financial support. Changes in that support could have far-reaching impacts on the wildlife interest and socio-economics of upland areas. Predicting the impacts of such changes is difficult, since they arise from responses to new economic circumstances. The effect of management change is also influenced by natural variation, such as the mosaic of plant communities, already present in the upland landscape. This paper sets out an approach that integrates theoretical models with field studies to investigate the effects of management …

Managing Resources By Grazing In Grasslands Dominated By Dominant Shrub Species, D. Magda, Cyril Agreil, Michel Meuret, E. Chambon-Dubreuil, P. -L. Osty

International Grassland Congress Proceedings

The European natural grasslands are attracting new attention because of their environmental value as habitats for threatened fauna and flora species and their contribution to the diversity of landscapes. Those responsible for the implementation of the European agri-environmental policy are hence encouraging livestock farmers to adopt grazing practices that contribute to the conservation of grassland biodiversity especially by limiting encroachment by dominant shrubs. However, current scientific knowledge and technical information are often insufficient to connect flock feeding and the impact of grazing on shrub dynamics and livestock farmers are not very enthusiastic about restoring or conserving “plant mosaics” including shrubs …

Challenges In Modelling Live-Weight Change In Grazed Pastures In The Australian Subtropics, C. K. Mcdonald, A. J. Ash

International Grassland Congress Proceedings

In sub-tropical regions there is enormous seasonal, annual and spatial variation in pasture quality and considerable variation in quality between pasture species. The heterogeneous structure of sub-tropical pasture swards means that process based modelling of liveweight change (LWC) is particularly difficult. In response to this complexity LWC has been expressed as a function of the length of the growing season and/or pasture utilization (McKeon et al. 2000), green leaf availability, or pasture availability and climate (Hirata et al. 1993). However, these relationships vary from year to year, often fail when species composition changes, and generally explain

Vegetation Dynamics Of Campos Under Grazing/Fire Regimes In Southern Brazil, Fernando L. F. De Quadros, J. P. P. Trinidade, D. G. Bandinelli, L. Pötter

International Grassland Congress Proceedings

Natural grassland vegetation in Southern Brazil, known as campos, has most likely evolved under a disturbance regime that included fire and grazing (Pillar et al., 1997). Nowadays, the composition of the vegetation of campos is grazing- and fire-dependent (Boldrini et al., 1997). Its importance can be evaluated by the fact that it represents 37 % of the state’s area and provides 77 % of the slaughtered cattle at Rio Grande do Sul (Barcellos et al., 2002). The objective of this experiment was to evaluate the vegetation dynamics of campos under grazing/fire regimes in order to explore the …

Accumulation Of Polyphenols And Major Bioactive Compounds In Plantago Lanceolata L. As A Medicinal Plant For Animal Health And Production, Y. Tamura, K. Yamaki

International Grassland Congress Proceedings

Producing animals without the use of feed-grade antibiotic growth promoters and chemical medicines is sought. Scientific studies with this aim have focused on medicinal plants to identify and quantify any beneficial effects that they might have on animal production. Plantago lanceolata L. has been used in herbal medicines and is currently being evaluated as a potential pasture species because of its beneficial effects on animal health. In the present study, the accumulation of polyphenols in P. Lanceolata is compared to that in principal pasture species, and genetic variation and environmental changes in the major bioactive compounds in P. Lanceplata are …

Effect Of Urea-Treated Pennisetum Pedicellatum And Supplementation Of Concentrates With Urea On Milk Production Of “Mossi” Ewes, V. M. C. Bougouma-Yameogo, A. J. Nianogo

International Grassland Congress Proceedings

The “Mossi” sheep is a near parent of “Djallonke” sheep that live in sudano-sahelian area of Burkina Faso. However, there are few available results on dairy production from this breed. The treatment of straw with urea is a technique used in several developing countries to improve the nutritional value of gramineous forages (Sourabié et al., 1995). The aim of this study was to test the influence on the performance of “Mossi” ewes and on milk composition of treatment of Pennisetum pedicellatum (Pp) with urea in comparison with addition of urea to the concentrate feed.

Effect Of Stocking Rate On A Stipa Breviflora Desert Steppe Community Of Inner Mongolia, G. Han, Walter D. Willms, M. Zhao, A. Gao, S. Jiao, David R. Kemp

International Grassland Congress Proceedings

Stocking rate is an important factor in grazing management. The stocking rate defines utilization and ultimately grazing pressure, which in turn affects grassland sustainability. Grassland sustainability is partly defined by its species composition and ultimately by its productivity. These attributes are unique for specific plant communities and the effect of stocking rate must be established for each in order to understand the community response to grazing and to determine its carrying capacity. While some information exists on the effects of stocking rate on livestock production in the Stipa breviflora Griseb. Desert Steppe (Wei et al., 2000), the effects on …

Using The N-Alkane Technique To Estimate The Herbage Intake And Diet Composition Of Cattle Grazing A Miscanthus Sinensis Grassland, Y. Zhang, Y. Togamura, K. Otsuki

International Grassland Congress Proceedings

Plant wax alkanes are now widely used as marker substances (Dove & Mayes 1991) for the estimation of forage intake and diet composition of grazing herbivores. The objective of this study was to evaluate this method with cattle grazing a M. sinensis grassland in Japan.

Reasons For The Premature Decline In Astragalus Adsurgens Stands In Kerqin Sandy Land, Qizhong Sun, Z. L. Wang, J. G. Han, Y. W. Wang, G. R. Liu

International Grassland Congress Proceedings

Diseases partly account for reductions in Astragalus adsurgens stand longevity. The effect of some cultural practices on the control of pests and diseases have been reported (Hou, 1986; Nan, 1996), but few reports have detailed the relationship among soil fertiliser status, diseases and premature stand decline. This study was conducted to investigate these relationships in order to extend the longevity of Astragalus adsurgens stands.

Selecting Grassland Species For Saline Environments, M. E. Rogers, A. D. Craig, T. D. Colmer, R. Munns, S. J. Hughes, P. M. Evans, P. G. H. Nichols, R. Snowball, D. Henry, J. Deretic, B. Dear, M. Ewing

International Grassland Congress Proceedings

In Australia, around 5.7 million hectares of agricultural land are currently affected by dryland salinity or at risk from shallow water tables and this figure is expected to increase over the next 50 years (LWRA, 2001). Most improved grassland species cannot tolerate the combined effects of salt and waterlogging and, therefore, the productivity of sown grasslands in salt-affected areas is low. However, there is potential to overcome the lack of suitably adapted fodder species by introducing new, salt and waterlogging-tolerant species and by diversifying the gene pool of proven species. Potential species include exotic, naturalised and native Australian grass, legumes, …

Effects Of The Stage Of Growth And Inoculation On Proteolysis In Field Pea Silage, L. Cavallarin, G. Borreani, S. Antoniazzi, E. Tabacco

International Grassland Congress Proceedings

Ensiling legumes is a good way of providing home-grown protein in dairy farms but severe protein degradation can occur when conserving legumes. Peas (Pisum sativum L.) are legumes with a high crude protein and starch content, that provide a high forage yield in a short growing period. Very little information is available on the protein value of field pea silage. The aim of the study was to investigate the effect of stage of maturity and inoculant application on proteolysis in field pea silage in the Po Valley, NW Italy.

Grass Silage: Factors Affecting Efficiency Of N Utilisation In Milk Production, P. Huhtanen, K. J. Shingfield

International Grassland Congress Proceedings

Key points

1. Low efficiency of N utilisation for milk production in cows fed grass silage-based diets is mainly due to excessive N losses in the rumen.
2. The type and extent of in silo fermentation can alter the balance of absorbed nutrients.
3. There is very little experimental evidence that the capture of N in the rumen can be improved by a better synchrony between energy and N release in the rumen. Nitrogen losses in the rumen can be reduced by decreasing the ratio between rumen degradable N and fermentable energy.
4. Rapeseed meal has increased milk protein output more than isonitrogenous soybean …