Agricultural Science Commons^™

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

IGC Proceedings (1977-2023)

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

IGC Proceedings (1977-2023)

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

IGC Proceedings (1977-2023)

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

IGC Proceedings (1977-2023)

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

IGC Proceedings (1977-2023)

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 …

Decision Support For Grassland Systems In Developing Countries, P. K. Thornton

IGC Proceedings (1977-2023)

Key points

1. Information flows in complex systems are often themselves highly complex, and decision support approaches based on linear input-output processes may have only limited impact.

2. How decisions are made, and how they can be appropriately supported, is often incompletely understood, in part because of inadequate understanding of the objectives and attitudes of all the decision makers involved.

3. Much of the developing world faces daunting problems in the coming 30 years, and appropriate information could play a critical role in dealing with these.

4. System complexity, household variability, and institutional intricacies have to be embraced rather than …

An Ecosystem Modelling Approach To Rehabilitating Semi-Desert Rangelands Of North Horr, Kenya, G. A. Olukoye, W. N. Wamicha, J. I. Kinyamario

IGC Proceedings (1977-2023)

Decreased rainfall, recurrent droughts and increased anthropogenic activities have led to a dramatic increase in wind erosion on pastoral lands of North Horr resulting in the reactivation of the once-stable sand dunes. This has degraded the vegetation and impoverished the local community. Mobile sand has a severe impact on dry season grazing areas (Omar & Abdal, 1994) and, therefore, affects pastoral livestock production. In North Horr, Suaeda monoica is important in camel production and for stabilising sand dunes but it has been over-utilized over the years. The objective of this study was to use ecosystem modelling approaches to examine the …

Riparian Management In Intensive Grazing Systems For Improved Biodiversity And Environmental Quality: Productive Grazing, Healthy Rivers, S. R. Aarons, M. Jones-Lennon, P. Papas, N. Ainsworth, F. Ede, J. Davies

IGC Proceedings (1977-2023)

Within high rainfall intensive grazing systems of southern Victoria, riparian zones are often degraded due to vegetation clearing, stock access and inappropriate farm management. Streams in these landscapes often have poor water quality and reduced biodiversity due to degraded terrestrial and aquatic ecosystems. Improved management of riparian zones depends on developing tools and practices for integration into productive grazing systems. This paper describes the approaches used and the tools developed in the ‘Productive Grazing, Healthy Rivers: Improving riparian and in-stream biodiversity’ project.

Contributions Of The United States Department Of Agriculture Natural Resources Conservation Service To Conserving Grasslands On Private Lands In The United States, L. Peter Heard

IGC Proceedings (1977-2023)

The future of biodiversity in the USA is tied inseparably to activities taking place on private lands. Agriculture is by far the most important user of these lands, with about 50% or 900M acres managed as private cropland, grassland or rangeland. Decisions made by America’s farmers and ranchers directly affect grasslands and their impact on food supply, biodiversity, soil protection and water quality. Agricultural programs and policies in the USA have had a large influence on the choices available to farmers and ranchers in land management. Since the 1930s, USDA’s Natural Resource Conservation Service (NRCS) has been working with farmers, …

Effect On Sward Botanical Composition Of Mixed And Sequential Grazing By Cattle And Sheep Of Upland Permanent Pasture In The Uk, J. E. Vale, M. D. Fraser, J. G. Evans

IGC Proceedings (1977-2023)

Previous work has shown benefits of sequential grazing by cattle and sheep, with superior liveweight gains being recorded for lambs grazing swards previously grazed by cattle. A preliminary study of the effects of mixed sheep and cattle grazing also suggested that more extensively grazed swards offer scope for complementary grazing between sheep and cattle. The aim of this experiment was to directly compare these two approaches of integrating the grazing of cattle and sheep.

Effect Of Mixed And Sequential Grazing By Cattle And Sheep Of Upland Permanent Pasture On Liveweight Gain, M. D. Fraser, J. E. Vale, J. G. Evans

IGC Proceedings (1977-2023)

Previous work has shown benefits of sequential grazing by cattle and sheep, with superior liveweight gains being recorded for lambs grazing swards previously grazed by cattle. A preliminary study of the effects of mixed sheep and cattle grazing also suggested that more extensively grazed swards offer scope for complementary grazing between sheep and cattle. The aim of this experiment was to directly compare these two approaches of integrating the grazing of cattle and sheep.

Effects Of Breed And Stage Of Growing Season On The Metabolic Profile Of Sheep Grazing Moorland, V. J. Theobald, M. D. Fraser, J. M. Moorby

IGC Proceedings (1977-2023)

Previous studies have shown that the diet of sheep grazing heather moorland is affected by season (Grant et al., 1987) and the proportion of Calluna vulgaris cover (Osoro et al., 2000). In order to investigate the impact of these factors on the associated nutrient supply of animals grazing heathland, blood samples were taken to monitor the metabolic status of different breeds of sheep at different stages of the growing season when grazing sites with different proportions of heather cover.

Characterising The Fermentation Capabilities Of Gut Microbial Populations From Different Breeds Of Cattle And Sheep Grazing Heathland, D. R. Davies, M. D. Fraser, V. J. Theobald, E. L. Bakewell

IGC Proceedings (1977-2023)

Previous studies have demonstrated differences in the diet composition of sheep and cattle when grazing heather moorland, and such differences may in turn lead to differences in rumen fermentation characteristics and associated adaptation to diet. To investigate this further an in vitro gas production experiment was conducted using inocula from different breeds of cattle and sheep grazing heathland.

The Performance Of Cattle On Lowland Species-Rich Neutral Grassland At Three Contrasting Grazing Pressures, B. A. Griffith, J. R.B. Tallowin

IGC Proceedings (1977-2023)

Grazing is an essential management practice for maintaining the nature conservation value of lowland semi-natural neutral grassland to control succession and create different faunal habitats via structural heterogeneity within the pasture (Duffey et al., 1974). However, there is a paucity of information on what would constitute a sustainable grazing intensity that will deliver the wildlife objectives and what the consequences of this management would be on growth rate of livestock and overall pasture output. An experiment was designed to quantify the ecological and agronomic consequences of imposing different grazing intensities on species-rich neutral grassland. The results will provide sward-based …

Nutritional Value Of Pasture Forage For Sheep In Krkonoše National Park, P. Homolka

IGC Proceedings (1977-2023)

This study describes the nutritional value of pastures in extreme mountain conditions in Krkonoše Mountains National Park. The Park performs important ecological and environmental functions. Extensive sheep grazing serves in the preservation of rare, protected and endangered species of plants (including endemics) and in the restoration of the biodiversity of meadows. The objective of this experiment was to estimate the production of plant biomass in these pastures and its digestibility by sheep.

Ruminal Proteolysis In Forages With Distinct Endopeptidases Activities, G. Pichard, C. Tapia, R. Larrain

IGC Proceedings (1977-2023)

Improving livestock efficiency in utilisation of nitrogen resources continues to be a major environmental and economic objective. Zhu et al. (1999) have shown that plant endopeptidases are activated as a response to cutting stress. Previous work in our laboratory explored over 300 entries of forage genotypes and found a broad diversity in enzymatic activity by means of hydrolysis in gelatine and direct autolysis assays in forage tissues. The objective of this work was to assess if the species previously identified as having high or low endopeptidase activity, would behave consistently when exposed to ruminal microbial proteolysis.

Effects Of Particle Size In Forage Samples For Protein Breakdown Studies, G. Pichard, C. Tapia

IGC Proceedings (1977-2023)

Coupling ruminal processes of hydrolysis and synthesis continues to be a research issue where more progress is needed. This requires the development of good protein assessment methods, particularly when representing the breakdown processes that occur in fresh pastures eaten by herbivores. Laboratory analyses need to deal with small and homogeneous samples, but the mechanical reduction of particle size may not reflect the actual digestion kinetics occurring when the original fresh forage is consumed. Such physical traits may alter the release of non-structural compounds and the penetration of microbial enzymes (Boudon et al., 2002). The objective of this work was …

A New System For The Evaluation Of The Fermentation Quality Of Silages, K. Weiß, E. Kaiser

IGC Proceedings (1977-2023)

Depending on the content of nitrate in green forage, the pattern of fermentation products in silages differ significantly (Weiß & Kaiser, 2001). The systems, which are now common in practice for evaluating the quality of silage fermentation, characterise fermentation quality incorrectly because the evaluation is influenced by the chemical composition of green forage. The aim of this work was to derive an evaluation system for fermentation quality, which is independent from the chemical composition of green forage.

Prediction Of Indigestible Ndf Content Of Grass And Legume Silages By Nirs, L. Nyholm, M. Rinne, M. Hellämäki, P. Huhtanen, J. Nousiainen

IGC Proceedings (1977-2023)

The future feed evaluation systems based on mechanistic digestion models require reliable estimates of forage digestible and indigestible NDF content (DNDF and INDF). The objective of this study was to examine the potential of near infrared reflectance spectroscopy (NIRS) in predicting INDF content of grass and legume silages.

Analysis Of Silage Fermentation Characteristics Using Transflectance Measurements By Near Infrared Spectroscopy, A. Martínez, A. Soldado, R. Garcia, D. Sánchez, B. De La Roza-Delgado

IGC Proceedings (1977-2023)

The fermentation end products as lactic acid, volatile fatty acids and ammonia-nitrogen, are important indicators of the efficiency of silage fermentation and are closely related to nutritive value of them (Jaster, 1995). Drying is problematic in the case of silage as many fermentation products are volatile and may get lost during the drying process. This may be a reason why NIR technology is being little used for the evaluation of silage fermentation characteristics. The feasibility of using near infrared transflectance spectroscopy to evaluate the content in fermentation end products of grass and maize fresh silage was investigated in this study.

Development Of A Method For The Fast And Complete Assessment Of Quality Characteristics In Undried Grass Silages By Means Of An Nir-Diode Array Spectrometer, H. Gibaud, C. Paul, J. M. Greef, B. Ruser

IGC Proceedings (1977-2023)

Traditionally, the determination of grass silage is very time consuming and needs a lot of manpower and chemicals. The advantages of conventional laboratory NIRS instruments are well known but their disadvantage lies in their lacking suitability for on-farm use. A new type of spectrometer based on diode arrays may be used for this purpose. However, these new instruments still need to be calibrated for an accurate estimate of the fermentative and nutritive value of wet and unchopped grass silage.

A Simple Method For The Correction Of Fermentation Losses Measured In Laboratory Silos, F. Weissbach

IGC Proceedings (1977-2023)

Dry matter (DM) losses caused by formation of gaseous fermentation products can be measured by different methods. The most common method (A) is measuring the difference between the DM input and output of a silo. Other methods are based on the measurement of the fermentation gases which spontaneously leave the silo, either directly by collecting them (B) in a special absorbent like KOH or, much more easily, by weighing the filled silo at the beginning and the end of the fermentation process (C). The figures obtained by B and C are substantially smaller than those by A. This difference represents …

Prediction Of Red Clover Content In Mixed Swards By Near-Infrared Reflectance Spectroscopy, B. Deprez, D. Stilmant, C. Clément, C. Decamps, A. Peeters

IGC Proceedings (1977-2023)

Because of the legume fixation capacity, their high protein content, digestibility and intake characteristics, more and more attention is paid to grassland clover content. In field experiments, clover content must often be determined, for example to quantify nitrogen flux or the best practices to manage such species (Stilmant et al., 2004). However hand sorting of clover and grass, even if accurate, is time-consuming and has a high labour cost. In comparison, accuracy of visual estimation of clover content, directly in the field, varies according to training and experience. Near-infrared reflectance spectroscopy (NIRS) has been proposed as a method for …

Intake And Milk Production Of Lactating Dairy Cows Grazing Diverse Forage Mixtures Over Two Grazing Seasons, K. Soder, M. A. Sanderson, J. L. Stack, L. Muller

IGC Proceedings (1977-2023)

Voluntary intake and stocking rate are key determinants of animal performance on pasture. Greater plant diversity in grassland plant communities has been linked to increased primary production, greater stability in response to disturbance, and reduced weed pressure. Thus, increasing plant diversity may be one approach to improving animal productivity. An experiment was conducted to determine the effects of forage diversity on intake and milk production of lactating dairy cows over two grazing seasons.

A Comparison Of Perennial Ryegrass Cultivars Differing In Heading Date And Grass Ploidy For Grazing Dairy Cows At Two Different Stocking Rates, M. O'Donovan, G. Hurley, L. Delaby, G. Stakelum

IGC Proceedings (1977-2023)

Animal productivity is the ultimate performance indicator of any new grass cultivar. Direct assessment is complex and expensive. Recent research has identified a number of important sward factors that influence intake and production. The most important factor appears to be green leaf mass. The objective of this two year study was to investigate the effects on milk yield, composition and grass intake of grass cultivars with contrasting heading dates (HD) and grass ploidies (PL) when grazed at different stocking rates.

In Situ Rumen Degradability Of Perennial Ryegrass Cultivars Differing In Ploidy And Heading Date In Ireland, V. Olsson, J. J. Murphy, F. P. O'Mara, M. O'Donovan, F. J. Mulligan

IGC Proceedings (1977-2023)

Grazed grass is the predominant feed in Irish dairy and beef cattle production systems. Knowledge of the degradability characteristics of protein in Irish forages is necessary for the establishment of protein values (PDIE and PDIN values) for these. This knowledge would also facilitate more accurate formulation of supplements for grass diets with the potential to reduce nitrogen (N) excretion.

Grazing Behaviour Of Beef Steers Grazing Kentucky 31 Endophyte Infected Tall Fescue, Q4508-Ar542 Novel Endophyte Tall Fescue, And Lakota Prairie Grass, H. T. Boland, G. Scaglia, J. P. Fontenot, A. O. Abaye, R. Smith

IGC Proceedings (1977-2023)

Tall fescue is the most dominant grass used for pasture in the U.S. covering over 14 million ha. As a result, fescue toxicosis is a major concern among producers, especially during the summer months when the symptoms, such as reduced weight gains, are most pronounced. Producers need alternative forages for grazing cattle that do not have the negative effects associated with endophyte infected tall fescue. The objective of this experiment was to determine the grazing behaviour of cattle on Kentucky 31 endophyte infected (E+) tall fescue (Festuca arundinacea Schreb.), Q4508-AR542 (Q) novel endophyte tall fescue, and Lakota (L) …

Caucasian Clover Is More Productive Than White Clover In Temperate Pastures, A. D. Black, D. J. Moot, R. J. Lucas

IGC Proceedings (1977-2023)

White clover (wc) (Trifolium repens) is present and is often the dominant legume in the >11 m ha of grassland in New Zealand (NZ). However, wc has limitations and normally contributes less than 20% of total annual pasture dry matter (DM) production. The use of a wider range of legume species is one way to increase legume percentage in wc/grass pastures. Caucasian (Cc) or Kura clover (Trifolium ambiguum) is a persistent legume which is slower to establish than wc but can increase total legume production (Cc plus volunteer wc) and hence N2 fixation and animal productivity. …

Response Of Warm-Season Grass Pasture To Grazing Period And Recovery Period Lengths, B. E. Anderson, W. H. Schacht

IGC Proceedings (1977-2023)

Grazing period and recovery period lengths are key variables influencing grassland production and composition. Systems with short grazing periods and lengthy recovery periods require numerous pastures. Relatively high facility and management costs associated with multiple-pasture systems can be justified only if plant response is favorable and/or if livestock production is improved. This study determined the effects of 4 different combinations of grazing period/recovery period lengths on percentage basal cover (PBC) and relative species composition (RSC) of seeded, warm-season grass pasture.

Yield Components In A Signal Grass-Clitoria Mixture Grazed At Different Herbage Allowance, R. Jiménez-Guillen, S. Rojas-Hernández, J. Olivares-Pérez, A. Martínez-Hernández, J. Pérez-Pérez

IGC Proceedings (1977-2023)

A Signal grass-Clitoria mixture provides good quality forage in the dry tropic of southern Mexico. However, its response in leaf and stem yields to grazing at different daily herbage allowances is not well documented. The objective of this study was to determine available and residual leaf and stem yields in a Signal grass (Brachiaria decumbens)-Clitoria (Clitoria ternatea) mixture grazed at different daily herbage allowance.