Plant Pathology Commons^™

Paying For Our Keep: Grasslands Decision Support In More-Developed Countries, Andrew D. Moore

IGC Proceedings (1977-2023)

Key points

1. A survey of decision support (DS) tools in grassland agriculture illustrates the diversity of decisions supported and of delivery technologies that are used. Larger, whole-enterprise planning tools are undergoing a period where their user interfaces are being adapted to better reflect the requirements and practice of advisory users.

2. The history of use of GrassGro, a ‘versatile simulator’, is used to illustrate how versatile tools attract a diverse range of users and uses. Lessons learnt by the GrassGro team are discussed.

3. Uptake rates of DS tools in grasslands are generally lower than was expected a decade …

Survey Of Tetraploid And Diploid Perennial Pastures In The Waikato For Number Of Spores Produced By The Fungus Pithomyces Chartarum, J. P. J. Eerens, W. W. Nichol, J. Waller, J. M. Mellsop, M. R. Trolove, M. G. Norriss

IGC Proceedings (1977-2023)

Facial eczema (FE) is a disease of livestock, caused by a toxin released into the bloodstream after digestion of spores of Pithomyces chartarum, a fungus residing in necrotic plant material in the base of pastures (di Menna & Bailey, 1973). Spore numbers tend to be highest in warm, humid conditions, where high post grazing residuals have lead to a build up of necrotic plant material. Tetraploid perennial ryegrass pastures tend to be more palatable, and with lower post gazing residuals, than equivalent diploid pastures; thus we hypothesised that spore numbers would be lower in tetraploid pastures. A survey of …

A Survey Of European Regional Adaptation In Italian Ryegrass Varieties, T. J. Gilliland, A. J. P. Wijk

IGC Proceedings (1977-2023)

Ryegrass is widely adapted to cool temperate eco-zones and breeders often submit individual varieties for testing in a number of EU countries. National testing programmes often combine data from several trial sites that may differ climatically, but not from sites in other member states, despite the possibility of high ecological similarity. Given increasing interest in ‘animal value’ characters (soluble sugars, lipids, sward geometry), additional testing for these would be valuable but is prohibited by capped or declining funding. Data sharing between EU national authorities could be advantageous but is inhibited by the lack of statistically valid data on the sensitivity …

Correlation Between Epiphytic Microflora And Microbial Pollution And Fermentation Quality Of Silage Made From Grasses, B. Osmane, J. Blūzmanis

IGC Proceedings (1977-2023)

Grass forage in Latvia is the main and inexpensive cow feed, however its composition and nutritive value differ during the growth period of grasses. The traits of grasses, their natural ensilage capacity, count of epiphytic microflora, the timing of harvest and ensilage making technology affecting the quality of grass silage are important issues to be studied. Silage making for the winter period is the treatment of green material to minimise the breakdown of nutrients being the results of biochemical and microbiological processes. The aim of the research was to clarify the methodologies to reduce the count of epiphytic microflora and …

Perennial Ryegrass Variety Differences In Nutritive Value Characteristics, T. J. Gilliland, R. E. Agnew, A. M. Fearson, F. E. A. Wilson

IGC Proceedings (1977-2023)

Animal grazing performance at grass is predominately determined by herbage intake rates, with high yielding dairy cows requiring up to 20 kg/d DM within a limited grazing time (Gibb, 1998). Grass nutritional factors such as seasonal patterns in digestibility and water-soluble carbohydrate levels have been linked to animal productivity (Davies et al., 1991), while sward surface height, herbage mass, bulk density and green leaf mass have been shown to promote high grazing intake (Barrett et al., 2001). Furthermore, fatty acid profiles have been shown to improve the unsaturated fatty acid composition of milk, with potential human health benefits …

Management Of Pasture Quality For Sheep On New Zealand Hill Country, D. I. Gray, J. I. Reid, P. D. Kemp, I. M. Brookes, D. Horne, P. R. Kenyon, C. Matthew, S. T. Morris, I. Valentine

IGC Proceedings (1977-2023)

The control of pasture quality over spring is central to the achievement of high levels of sheep performance on hill country. Despite this, with the exception of the work of Lambert et al. (2000), little is known about how farmers actually manage pasture quality. The purpose of this research was to describe how a high performing hill country farmer manages pasture quality on their sheep area over spring and from this develop a framework that will assist other farmers improve their pasture management.

Production And Plant Density Of Sulla Grazed By Sheep At Three Growth Stages, H. Krishna, P. D. Kemp

IGC Proceedings (1977-2023)

Sulla is one of the few temperate forage legumes that contain enough condensed tannins to improve the efficiency with which livestock use protein (Marshall et al., 1979). However, it usually is productive only for approximately 14 months in New Zealand, and little is known of its response to grazing. This paper reports on the production and persistence of Sulla cv. Necton, when using growth stage as the criterion for time of grazing by sheep in a maritime, temperate environment.

Spring Calving Suckler Beef Systems: Influence Of Grassland Management System On Herbage Availability, Utilisation, Quality And Cow And Calf Performance To Weaning, M. J. Drennan, M. Mcgee, S. Kyne, B. O'Neill

IGC Proceedings (1977-2023)

Suckler beef systems in Ireland are primarily based on grass. Suckler systems vary in intensity but many operate low input systems and participate in REPS (Rural Environmental Protection Scheme). As there is a considerable cost associated with second-cut silage this research compared a two-cut system with a simplified low input one-cut system.

The Importance Of Patch Size In Estimating Steady-State Bite Rate In Grazing Cattle, E. D. Ungar, N. Ravid, T. Zada, E. Ben-Moshe, R. Yonatan, S. Brenner, H. Baram, A. Genizi

IGC Proceedings (1977-2023)

Since the pioneering work of Black and Kenney (1984), various intake studies have been conducted at the spatial scale of a single feeding station ("patch") to elucidate the processes that determine instantaneous intake rate (e.g. Laca et al., 1994). While these are well-suited for patch depletion studies, it is less clear how well they represent non-patchy and relatively homogeneous environments (Ungar & Griffiths, 2002). Clearly, grazing should be restricted to the upper grazing horizon (i.e. layer of bites), but sample duration may be insufficient to characterize steady-state behaviour, especially when grazing commences on an empty mouth. We examined the …

Performance Of Meat Goats Grazing Winter Annual Grasses In The Piedmont Of The Southeastern Usa, J-M. Luginbuhl, J. P. Mueller

IGC Proceedings (1977-2023)

In the Southeastern United States, meat goats (Capra hircus hircus) are becoming increasingly important contributors to the income of many small producers. Meat goats perform well in grazing situations if grazing management practices match their grazing behavior. Nevertheless, little research data are available from the region specifically directed toward forage feeding programs for goats reared for meat production. Hart et al. (1993) reported that growing Alpine, Angora and Nubian kids grazed on high quality Triticum aestivum forage gained 50 g/d, whereas Kiesling et al. (1994) reported gains ranging from 65 to 141 g/d in growing Angora …

The Effect Of Early And Delayed Spring Grazing On The Milk Production, Grazing Management And Grass Intake Of Dairy Cows, E. Kennedy, M. O'Donovan, J. P. Murphy, L. Delaby, F. P. O'Mara

IGC Proceedings (1977-2023)

Earlier access to pasture can increase the overall proportion of grazed grass in the diet of the spring calving dairy cow. Further benefits can also be achieved from early turnout, including improved animal production, increased sward utilisation and enhanced sward quality (O’Donovan et al., 2004). The objective of this study was to compare the effect of initial spring grazing date and stocking rate on the performance of spring calving dairy cows.

Intake Characteristics Of Diploid And Tetraploid Perennial Ryegrass Varieties When Grazed By Simmental X Holstein Yearling Heifers Under Rotational Stocking Management, R. J. Orr, J. E. Cook, K. L. Young, R. A. Champion, A. J. Rook

IGC Proceedings (1977-2023)

Orr et al. (2003) measured large differences in dry matter (DM) intake rate between 15 intermediate-heading perennial ryegrass varieties when they were continuously stocked with sheep and subsequently explored the extent to which, for 5 of these varieties, these differences could be explained by chemical and morphological traits (Orr et al., 2004a) which could be targeted in grass breeding programmes. Here, four of the 15 varieties, which within ploidy had low or high intake characteristics when grazed by sheep, were rotationally stocked with cattle and intake and sward factors were measured.

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 …

   ---

   Go to article

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 …

   ---

   Go to article

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 …

   ---

   Go to article

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 …

   ---

   Go to article

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 …

   ---

   Go to article

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.