Digital Commons Network^™

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 …

Breeding Milestones Correspond With Changes To Wheat Rhizosphere Biogeochemistry That Affect P Acquisition, Rebecca Kay Mcgrail, David A. Van Sanford, David H. Mcnear Jr.

Plant and Soil Sciences Faculty Publications

Breeding wheat (Triticum aestivum L.) has resulted in small gains in improved nutrient acquisition and use as numerous traits are involved. In this study, we evaluated the impact of breeding on P-acquisition and identified both plant and soil variables that could be used to inform the selection of germplasm with increased P acquisition efficiency. We previously screened a historic panel of winter wheat cultivars for root system architecture and root tip organic acid content when grown in P-deficient solution/agar and used these characteristics together with breeding history to develop a predicted P extraction potential (PEP). We tested the validity …

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.

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.

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.

Isomerization Of Galactose To Tagatose: Recent Advances In Non-Enzymatic Isomerization, Jikai Zhao, Zhuo Wang, Qing Jin, Danyi Feng, Juhee Lee

School of Earth, Environmental, & Marine Sciences Faculty Publications

The valorization of galactose derived from acid whey to low-calorie tagatose has gained increasing attention. Enzymatic isomerization is of great interest but faces several challenges, such as poor thermal stability of enzymes and a long processing time. In this work, non-enzymatic (supercritical fluids, triethylamine, arginine, boronate affinity, hydrotalcite, Sn-β zeolite, and calcium hydroxide) pathways for galactose to tagatose isomerization were critically discussed. Unfortunately, most of these chemicals showed poor tagatose yields (70%). The latter is able to form a tagatose–calcium hydroxide–water complex, which stimulates the equilibrium toward tagatose and prevents sugar degradation. Nevertheless, the excessive use of calcium hydroxide may …

Benthic Habitat Mapping Of Mountain Top Bank Within The Northern Gulf Of Mexico Through Integrated Geophysical And Visual Data Analysis, Bethany Pertain

Master's Theses

Mesophotic coral ecosystems (MCEs) are among the seafloor ecosystems that have been poorly studied throughout the world’s oceans, but they are a vital and diverse ecosystem that should be prioritized for future mapping and ecological studies. Priority should be given to them because they possess natural, social, and economic values, and face a variety of threats, all of which, if not better understood will result in the loss of this unique ecosystem. Insights into these ecosystems, among other deep-sea environments, are lacking due to difficulty accessing them, inherent lag between data collection by an autonomous system and observation by a …

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.

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.

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. …

Genetic Alternatives For Dairy Producers Who Practise Grazing, H. D. Norman, J. R. Wright, R. L. Powell

IGC Proceedings (1977-2023)

The decline in cow fertility has had a negative impact on all dairy producers, especially those that practise seasonal calving with pasture-based dairying. One alternative that is being tried in the United States (US) by a few graziers is to use bulls from New Zealand (NZ) because NZ producers have practised seasonal calving for some time. However, genotype-environment interaction is a concern; genetic correlations that were derived by the International Bull Evaluation Service (2004) between bull rankings from different countries were often lower for NZ than for other countries. The objective of this study was to compare the performance of …

Suitability Of Small And Large Size Dairy Cows In A Pasture-Based Production System, M. Steiger Burgos, R. Petermann, P. Hofstetter, P. Thomet, S. Kohler, A. Munger, J. W. Blum, P. Kunz

IGC Proceedings (1977-2023)

Pasture-based dairy production with greatly reduced supplemental feeding and block-calving in spring is increasingly applied in Switzerland. The prevalent cow type has been selected mainly for high individual production in a barn feeding system with balanced diet. This cow type has continuously increased in size over the last 30 years. The question arises whether this type is suitable for the new system, and particularly if cow size is a critical factor. Theoretically a large, heavy type of cow has a higher intake capacity, while the nutrient requirements for a small, light type are easier to satisfy.

The Effect Of Stocking Rate And Lamb Grazing System On Sward Performance Of Trifolium Repens And Lotus Corniculatus In Uruguay, F. Montossi, R. San Julián, M. Nolla, M. Camesasca, F. Preve

IGC Proceedings (1977-2023)

Lambs have a great potential to diversify and stimulate meat and wool production and economical returns within the industry. The main objective of this study was to evaluate different feeding and management alternatives for the production of high quality wool and meat as well as their effects on sward characteristics in the Basaltic region of Uruguay.

Pasture Intake And Milksolids Production Of Different Strains Of Holstein-Friesian Dairy Cows, J. L. Rossi, K. A. Macdonald, B. S. Thorrold, C. Holmes

IGC Proceedings (1977-2023)

Cows of high yield potential require high daily dry matter intakes (DMI) to meet their increased energy demand. For this reason, DMI may be constrained in a pasture-based system. Daily milksolids yield and DMI of three strains of Holstein-Friesian dairy cows farmed at low and high feeding level during season 2002- 2003 are reported.

Does The Feeding Behaviour Of Dairy Cows Differ When Fed Ryegrass Indoors Vs. Grazing?, A. V. Chaves, A. Boudon, J. L. Peyraud, R. Delagarde

IGC Proceedings (1977-2023)

Dairy cows eating ryegrass ingest smaller boli when grazing than when fed indoors (93 vs. 142 g; Boudon et al., 2004). To investigate whether this difference in bolus affects feeding behaviour of the cows, an automated system (chewing halters) was used to monitor feeding behaviour of cows given ad libitum access to perennial ryegrass in individual feed troughs (indoor feeding, IF) or at pasture (grazing, GR).

Modelling The Effect Of Breakeven Date In Spring Rotation Planner On Production And Profit Of A Pasture-Based Dairy System, P. C. Beukes, B. S. Thorrold, M. E. Wastney, C. C. Palliser, G. Levy, X. Chardon

IGC Proceedings (1977-2023)

The breakeven date is the expected date when pasture supply exceeds cow demand. This date is used to plan the rotation rates, slow during the winter, when pasture growth is low and cows are dry, to a fast rotation in spring, when growth is accelerating and most cows lactating. This date is influenced by regional climate, mainly rainfall and soil temperature, which affects timing and rate of growth acceleration. The objective of this modeling exercise was to explore the effect of the breakeven date on milksolids (MS), grass silage, farm cover and economic farm surplus (EFS) over different climate years …

Development Of A Model Simulating The Impact Of Management Strategies On Production From Beef Cattle Farming Systems Based On Permanent Pasture, M. Jouven, R. Baumont

IGC Proceedings (1977-2023)

Grazing systems in Europe increasingly have to meet environmental objectives, which influence management strategies. A deterministic model describing farming system dynamics is being developed in order to elucidate interactions between nature-friendly management practices, as for example late (after flowering) hay harvest or moderate stocking rate, and agricultural output.

Intake By Lactating Goats Browsing On Mediterranean Shrubland, M. Decandia, G. Pinna, A. Cabiddu, G. Molle

IGC Proceedings (1977-2023)

In Mediterranean regions goat feeding systems are mainly based on shrubland that contain a wide variety of species. There are only a few equations for predicting feed intake of stall-fed goats (Luo et al., 2004). The objective of this study was to develop a model for predicting the intake of lactating goats browsing on Mediterranean shrubland.

The Impact Of Concentrate Price On The Utilization Of Grazed And Conserved Grass, P. Crosson, P. O'Kiely, F. P. O'Mara, M. J. Drennan, M. Wallace

IGC Proceedings (1977-2023)

A linear programming model was designed and constructed to facilitate the identification of optimal beef production systems under varying technical and policy scenarios. The model operates at a systems level and most activities that could occur in Irish spring-calving, suckler beef production systems are included. In this paper, the components of the model are described together with a simple application of the model involving changing concentrate prices.

Modelling Urine Nitrogen Production And Leaching Losses For Pasture-Based Dairying Systems, I. M. Brookes, D. J. Horne

IGC Proceedings (1977-2023)

Urine from dairy cattle grazing pastures with high crude protein (CP) concentrations is a major source of N lost in drainage water from New Zealand farms. This paper provides predictions of urinary N leaching losses for a range of stocking rates and levels of supplementation.

Effect Of Nitrogen On The Radiation Use Efficiency For Modelling Grass Growth, R. Lambert, A. Peeters

IGC Proceedings (1977-2023)

When nitrogen (N) is not at a sufficient level to permit maximum growth rate, dry matter production is reduced. Models of plant growth in relation to solar radiation intercepted by the crop have been largely used. According to these models, N deficiency can act on the leaf extension and thus on the quantity of radiation intercepted by the crop, but also by reducing the radiation use efficiency of the crop (RUE) (Bélanger, 1990). The effect of N on the RUE of ryegrass swards is determined and discussed.

The Meal Criterion Estimated In Grazing Dairy Cattle: Evaluation Of Different Methods, P. A. Abrahamse, D. Reynaud, J. Dijkstra, S. Tamminga

IGC Proceedings (1977-2023)

The meal criterion (MC) has been found a useful tool to pre-treat intake behaviour data in dairy cows. It was defined as the longest interval between bouts that belong to the same meal (Tolkamp & Kyriazakis, 1999), necessary to cluster bouts to meals. The method of Yeates et al. (2001) calculating the log_e-transformed intervals between bouts and using the Gaussian-Gaussian-Weibull (GGW) model to calculate the MC was found to provide the best estimation of the MC in biological as well as statistical terms. However, in grazing dairy cattle the MC-estimation has only been carried out by Rook …

Radiation Use Efficiency Of Ryegrass: Determination With Non Cumulative Data, R. Lambert, A. Peeters

IGC Proceedings (1977-2023)

The growth of a crop is generally described as biomass accumulation per unit time. Monteith (1977) developed a model of growth where biomass accumulation is related to solar radiation intercepted by the crop. This model has been largely used for different crops. The conversion factor between radiation absorbed or intercepted by the crop and the biomass production is called “radiation use efficiency” or “dry matter radiation quotient”. Radiation use efficiency (RUE) is usually calculated as the regression coefficient of the linear relationship between crop biomass measured repeatedly during growth and cumulated intercepted or absorbed solar radiation. Demetriades-Shah et al. …