231 research outputs found

    Improving cost-effectiveness of supplementation systems for breeder herds in northern Australia

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    Low level strategic supplements constitute one of the few options for northern beef producers to increase breeder productivity and profitability. Objectives of the project were to improve the cost-effectiveness of using such supplements and to improve supplement delivery systems. Urea-based supplements fed during the dry season can substantially reduce breeder liveweight loss and increase fertility during severe dry seasons. Also when fed during the late wet season these supplements increased breeder body liveweight and increased fertility of breeders in low body condition. Intake of dry lick supplements fed free choice is apparently determined primarily by the palatability of supplements relative to pasture, and training of cattle appears to be of limited importance. Siting of supplementation points has some effect on supplement intake, but little effect on grazing behaviour. Economic analysis of supplementation (urea, phosphorus or molasses) and weaning strategies was based on the relative efficacy of these strategies to maintain breeder body condition late in the dry season. Adequate body condition of breeders at this time of the year is needed to avoid mortality from under-nutrition and achieve satisfactory fertility of breeders during the following wet season. Supplements were highly cost-effective when they reduced mortality, but economic returns were generally low if the only benefit was increased fertility

    Effects of a nitrogen-based supplement on intake, live weight and body energy reserves in breeding Bos indicus cross cows

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    Breeding cows grazing seasonally dry rangelands usually lose substantial live weight (LW) during the dry season, when in late pregnancy. An experiment investigated the effects of feeding a N-based supplement to cows in late pregnancy on voluntary intake, total live weight (T-LW), body condition score (CS) and estimated body net energy content (Body-NE), as well as carry-over effects during lactation. In Phase A for 139 days from mid-pregnancy, mature Bos indicus cross breeders [initially 438 kg T-LW and 5.7 CS units (9-point scale)] were fed in pens on low quality tropical grass hay alone (Control) or with a N supplement (Supplemented). Most (17/22) of the cows calved during this interval. Voluntary hay intake averaged 6.74 g DM/kg T-LW/d in Control cows, and was increased by 35% (P<0.001) when supplement was fed. As a result, feeding supplement reduced loss in conceptus-free live weight (CF-LW) by 30% (from 1.11 kg/d to 0.78 kg/d; P<0.001) and in Body-NE by 20% (from 26.6 to 21.2 MJ NE/d; P = 0.007). Control cows mobilized 24% of maternal LW and 32% of body energy when fed low quality hay during late pregnancy, and these losses were substantially reduced when a N-based supplement was fed. During Phase B, when the lactating cows with their calves grazed a high quality rainy season grass-Stylosanthes pasture, the previously supplemented cows produced more milk (P = 0.065) and their calves grew faster (P = 0.077) in early lactation than Control cows. In addition, during early lactation Control cows exhibited compensatory LW gain relative to the Supplemented cows (0.80 vs. 0.43 kg/d, respectively; P<0.001) and there was no discernable weight difference between the groups by 205 days of lactation. In conclusion the losses in LW and body energy reserves by late pregnant cows fed low quality tropical grass hay were substantially reduced by a N supplement, but the differences were not maintained when the cows subsequently grazed high quality pasture

    Project LOCOST: Laser or Chemical Hybrid Orbital Space Transport

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    A potential mission in the late 1990s is the servicing of spacecraft assets located in GEO. The Geosynchronous Operations Support Center (GeoShack) will be supported by a space transfer vehicle based at the Space Station (SS). The vehicle will transport cargo between the SS and the GeoShack. A proposed unmanned, laser or chemical hybrid orbital space transfer vehicle (LOCOST) can be used to efficiently transfer cargo between the two orbits. A preliminary design shows that an unmanned, laser/chemical hybrid vehicle results in the fuel savings needed while still providing fast trip times. The LOCOST vehicle receives a 12 MW laser beam from one Earth orbiting, solar pumped, iodide Laser Power Station (LPS). Two Energy Relay Units (ERU) provide laser beam support during periods of line-of-sight blockage by the Earth. The baseline mission specifies a 13 day round trip transfer time. The ship's configuration consist of an optical train, one hydrogen laser engine, two chemical engines, a 18 m by 29 m box truss, a mission-flexible payload module, and propellant tanks. Overall vehicle dry mass is 8,000 kg. Outbound cargo mass is 20,000 kg, and inbound cargo mass is 6,000 kg. The baseline mission needs 93,000 kg of propellants to complete the scenario. Fully fueled, outbound mission mass is 121,000 kg. A regeneratively cooled, single plasma, laser engine design producing a maximum of 768 N of thrust is utilized along with two traditional chemical engines. The payload module is designed to hold 40,000 kg of cargo, though the baseline mission specifies less. A proposed design of a laser/chemical hybrid vehicle provides a trip time and propellant efficient means to transport cargo from the SS to a GeoShack. Its unique, hybrid propulsion system provides safety through redundancy, allows baseline missions to be efficiently executed, while still allowing for the possibility of larger cargo transfers

    Improving cost-effectiveness of supplementation systems for breeder herds in northern Australia

    Get PDF
    Low level strategic supplements constitute one of the few options for northern beef producers to increase breeder productivity and profitability. Objectives of the project were to improve the cost-effectiveness of using such supplements and to improve supplement delivery systems. Urea-based supplements fed during the dry season can substantially reduce breeder liveweight loss and increase fertility during severe dry seasons. Also when fed during the late wet season these supplements increased breeder body liveweight and increased fertility of breeders in low body condition. Intake of dry lick supplements fed free choice is apparently determined primarily by the palatability of supplements relative to pasture, and training of cattle appears to be of limited importance. Siting of supplementation points has some effect on supplement intake, but little effect on grazing behaviour. Economic analysis of supplementation (urea, phosphorus or molasses) and weaning strategies was based on the relative efficacy of these strategies to maintain breeder body condition late in the dry season. Adequate body condition of breeders at this time of the year is needed to avoid mortality from under-nutrition and achieve satisfactory fertility of breeders during the following wet season. Supplements were highly cost-effective when they reduced mortality, but economic returns were generally low if the only benefit was increased fertility

    Carbon Disclosure, Performance and the Green Reputation of Higher Educational Institutions in the UK

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    Purpose This study aims to investigate the carbon emission disclosures (CED) and performance of UK higher educational institutions (HEIs) and the associated impact on their environmental reputation. The paper argues that HEIs possess distinct characteristics that make comparisons with profit-oriented companies problematic and misleading. Design/methodology/approach The green score published by the People and Planet organisation provided the population for this analysis. All universities with a 2012 score were entered into the initial sample. The association between green reputation, CED and carbon performance was examined using a robust least squared regression model. The green score published in 2019 was then compared with this to confirm whether the findings still held. Findings CED, carbon emissions and carbon audit were found to have highly significant determinant relationships with HEIs’ green reputation status at a 1% significance level. Research limitations/implications The impact of CED and carbon performance indicators needs to have a clear relationship with reputation to motivate HEIs to act and disclose. Originality/value The study is distinct in investigating the impact of CED and carbon performance by UK HEIs on their environmental reputation. The study shows whether, and how, the HEI CED and carbon performances contribute towards their environmental reputation. HEIs have distinct characteristics from profit-seeking organisations and thus tailored research is required. </jats:sec

    Faecal near Infrared Spectroscopy to Measure the Diet Selected and Productivity of Grazing Ruminants

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    In ruminants near infrared spectroscopy of faeces (F.NIRS) can measure the concentrations of faecal constituents such as N and fibre. It can also directly estimate many diet attributes, including total N, fibre, digestibility and the major plant groups (e.g. monocots versus dicots, and some plant species). In some situations F.NIRS can be used to estimate voluntary intake and liveweight change, but it is difficult to encompass animal effects (e.g. lactation, maturity), pasture availability or mineral deficiencies. Application of F.NIRS, especially in conjunction with other measurements (e.g. metabolizable energy intake calculated from liveweight change, 13C/12C ratio in faeces, microbial protein synthesis and phosphorus concentrations in faeces) can provide valuable and reliable information about the nutritional status of grazing ruminants. Examples where F.NIRS has been used to measure the nutritional status of grazing cattle and sheep are described for extensive and intensive tropical production systems in northern Australia, the Caribbean, the Amazonian humid tropics, and for temperate pastures in Europe. F.NIRS can be applied to routinely and economically measure the nutrient intakes of grazing ruminants, and such information used to modify herd management

    High-cut harvesting of maize stover and genotype choice can provide improved feed for ruminants and stubble for conservation agriculture

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    In smallholder crop–livestock systems where maize (Zea mays L.) is a staple cereal, the stover is usually an important but low-quality ruminant feed. Maize stover has various competing uses, and optimal allocation of stover, particularly for forage and mulch, is essential for improving whole-farm productivity and sustainability. Knowledge that feed quality increases with height in maize stover provides opportunities. An experiment investigated the effects of a high cutting height of stover at grain harvest (cut at two internodes below the lowest ear) on the yields and feed quality of the upper and lower stover (stubble) fractions. Measurements were made on six maize genotypes at two sites during two cropping seasons in Ethiopia. The upper stover fraction (USF) on average comprised 674 g kg–1 of the entire stover and was also substantially higher (P <.001) than the lower stover fraction (LSF) in in vitro dry matter digestibility (527 vs. 450 g kg−1 dry matter [DM]) and total N concentrations (8.8 vs. 6.2 g kg−1 DM) and was lower in fiber. Stems (including leaf sheath and tassel), husks (including shank), and leaf blade comprised 484, 310, and 206 g kg−1 of the USF, respectively. Yields and feed quality of stover varied among genotypes and environments. Use of an USF can provide a feedstuff of increased nutritional quality for ruminants, but the efficacy of the LSF for mulch requires investigation. In conclusion, a simple management change to harvest maize stover at higher stubble height combined with use of appropriate genotypes can provide higher-quality feed while leaving stubble for conservation agriculture

    Variations in seed and post-harvest residue yields and residues quality of common bean ( Phaseolus vulgaris L.) as a ruminant feedstuff

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    Common bean is widely grown as a food legume and the post-harvest crop residues (CR) (i.e. haulm + pod wall (HPW)) are valuable as ruminant feedstuffs. The yields and constituents indicative of nutritive value for ruminants of the HPW from a wide range of common bean genotypes (G) were examined at 4 trial sites in Ethiopia during the 2013 main cropping season to assess the extent of genetic variation among G for simultaneous improvement of both HPW attributes and seed yield. Attributes measured were seed and HPW yields and the amounts of the morphological components, their concentrations of total nitrogen (N), neutral detergent fibre (aNDFom) and acid detergent fibre (ADFom), and the dry matter digestibility (DMD). The constituents were measured using near infrared spectroscopy (NIRS) and calibrations based on a large set of reference tropical forages and CR (including common bean), and were validated against other CR reference samples. These CR quality attributes were very well predicted with R2v and RPDv ranging from 0.90 to 0.98 and 3.13–7.36, respectively. There was considerable variation in yields of HPW and seed, and in the proportions and attributes of the HPW fractions among the common bean G. Trial site means for yields of HPW and seed ranged from 0.74 to 2.54 t/ha and 0.79–2.62 t/ha, respectively while for N, aNDFom and ADFom concentrations and DMD of HPW ranged from 7.7 to 11.4 g/kg DM, 648–739 g/kg DM, 502–585 g/kg DM, and 467–570 g/kg DM, respectively. Environment (E), as represented by site, generally affected the yields of HPW and seed (P < 0.001) and nutritive value of the HPW fractions (P < 0.05) as feedstuffs. Seed yield was positively correlated with HPW yield both within and across trial sites (r = 0.92; P < 0.0001), but in general seed yield was not related to the N concentration. Across all sites, seed yield was positively correlated (r = 0.68; P < 0.0001) with haulm DMD. Although this correlation may be due to variation associated with E rather than G, it is nevertheless important in that selection for higher seed yield is likely to also increase metabolisable energy (ME) content of the HPW. There were G x E interaction effects on yields of HPW (P < 0.0001) and seed (P = 0.011), but these were generally less important than E effects which explained 52–58% of the variation. In conclusion the study demonstrated that it is possible to identify genotypes such as ECAB0081 which combine high yields of both seed and HPW, and with HPW attributes which improve their quality as ruminant feedstuffs

    Ecosystem service assessment of selected wetlands of Kolkata and the Indian Gangetic Delta: multi-beneficial systems under differentiated management stress

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    © 2019, The Author(s). A structured literature review using the search term ‘ecosystem services’ found few relevant studies relating to three contrasting wetlands in West Bengal: the unpopulated Sudhanyakhali Island in the Sundarbans National Park, the populated Gosaba Island separated from Sudhanyakhali Island by a narrow channel, and the East Kolkata Wetland (EKW). Subsequent structured review focused on the EKW using specific service-related terms located only 2 provisioning, 6 regulating, 1 cultural and 3 supporting services. Few services are currently recognized in the literature, with significant gaps in whole service categories. Significantly, there was no published evidence of a systemic overview of service production at these sites. Field observations and stakeholder dialogue informed assessment of ecosystem services using the Rapid Assessment of Wetland Ecosystem Services (RAWES) approach, adopted by the Ramsar Commission, on both islands and three discretely different areas of the EKW. The RAWES surveys found that 32 of 36 ecosystem services were produced from at least one assessed wetland site. Despite low sample size, statistically significant differences were observed in the range of services produced between the five wetland sites and the geographical range at which benefits accrued, explained by differing wetland characteristics and management regimes. Were decisions based solely on evidence provided by existing published knowledge, few ecosystem services would be considered and, potentially, whole ecosystem service categories might be overlooked. Importantly, there would also be no systemic account of service production and interdependencies. RAWES assessment serves as a practical, rapid and systemic approach, taking account of interdependent ecosystem services, supporting protection of the ecological character and achievement of wise use of wetlands. RAWES can also help redress perceptions that the values of peri-urban wetlands are currently under-represented
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