School of Agriculture, Food and Ecosystem Sciences - Research Publications
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ItemNo Preview AvailableImpact of Haemonchus contortus infection on feed intake, digestion, liveweight gain, and enteric methane emission from Red Maasai and Dorper sheep(Frontiers Media SA, 2023-01-01)A study was conducted with Red Maasai and Dorper lambs to evaluate the effects of infection with the gastrointestinal nematode (GIN) Haemonchus contortus on feed intake, liveweight gain (LWG), feed energy and nitrogen partitioning, and enteric methane (CH4) emissions. Six- to seven-month-old Red Maasai (n=12) and Dorper (n=12) lambs were randomly allocated to three treatments (n=8, four lambs per breed) in a 2×3 factorial cross-over study over two periods (P1 and P2) of 36 days each. The treatments consisted of three combinations of GIN infection and feeding level: Infected + ad libitum feeding (I-adlib), uninfected + ad libitum feeding (Un-adlib), and uninfected + restricted feeding (Un-restd), across the two breeds. Lambs in the I-adlib group were trickle-infected daily with 1,000 L3 stage larvae of H. contortus for four consecutive days (Days 1–4), whereas lambs in the other experimental treatments were kept GIN free. The feed intake was measured daily. Liveweight (LW), faecal egg counts (FEC), and packed cell volume (PCV) were measured on Day 1 and weekly thereafter. On Days 29–33 total faecal and urine outputs were determined in metabolic crates. The lambs were then housed in respiration chambers for three consecutive days (Days 34–36). There was a washout period of 21 days before P2 started. Uninfected lambs (Un-adlib and Un-restd) had undetectable FEC throughout the study. On Day 36, FEC did not differ between the breeds (P>0.05). Infected lambs (I-adlib) had lower PCV than uninfected (Un-adlib and Un-restd) lambs on day 36. Neither breed nor infection influenced feed and nutrient intake, but as expected, restricted-fed lambs had a lower intake (P<0.05). The LWG of Un-adlib lambs was significantly higher than that of I-adlib and Un-restd lambs (P<0.05), whereas there was no breed difference (P>0.05). Neither breed nor infection affected feed digestibility, nitrogen retention or energy metabolisability (P>0.05). However, feed restriction decreased feed intake, LWG and N retention, whereas feed digestibility and energy metabolisability were unaffected. Neither daily CH4 emissions nor yield (per unit of feed intake) were affected by experimental infection, but Un-restd lambs had lower CH4 emissions per day. Red Maasai lambs had consistently lower daily CH4 emissions and yields than Dorper (P<0.01). This study confirmed the relative resistance of indigenous sheep (Red Maasai) to H. contortus infection, but the increased CH4 emission and yield due to GIN observed in other studies was not confirmed. Further investigations are needed to test whether in environments with multiple stress factors, local or indigenous breeds or their crossbreeds with exotic breeds may be better equipped to sustain production and simultaneously have a reduced carbon footprint than purebred exotic breeds.
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ItemNo Preview AvailableWater use strategy determines the effectiveness of internal water storage for trees growing in biofilters subject to repeated droughts(ELSEVIER, 2023-10-10)Impervious surfaces create large volumes of stormwater which degrades receiving waterways. Incorporating trees into biofilters can increase evapotranspiration and therefore reduce stormwater runoff. Tree species with i) high water use, ii) drought tolerance and iii) rapid and full recovery after drought have been suggested for biofilters to maximise runoff reduction while minimising drought stress. Moisture availability fluctuates greatly in biofilter substrates and trees growing in biofilters will likely experience multiple, extended drought events that increase trade-offs between these traits. Providing an internal water storage has the potential to reduce tree drought stress and increase evapotranspiration. Two urban tree species (Agonis flexuosa and Callistemon viminalis) were grown in plastic drums with biofilter profiles. Three irrigation treatments were used: well-watered, drought with an internal water storage and drought without an internal water storage. Transpiration, leaf water potential and biomass were measured to determine the effect of biofilter internal water storage and repeated drought events on tree water use, drought stress and growth. Biofilter internal water storage improved water use and reduced drought stress for A. flexuosa, whereas C. viminalis reduced leaf loss but saw no change in water use or drought stress. A. flexuosa with biofilter internal water storage was able to recover transpiration to well-watered levels after repeated droughts, while C. viminalis experienced reduced recovery ability. It is recommended all biofilters planted with trees should have internal water storage. In systems with lower moisture availability a species with more stomatal control, such as A. flexuosa, is recommended. If selecting a species with less stomatal control, such as C. viminalis, the internal water storage volume needs to be increased to avoid drought stress.
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ItemNo Preview AvailableSustainable management of Eucalyptus pellita plantations: A review(ELSEVIER, 2023-06-01)
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ItemInfluence of particle granulometry and panel composition on the physico-mechanical properties of ultra-low-density hemp hurd particleboard(Wiley, 2023)This study investigated Australian hemp hurd (Cannabis sativa L., “Frog One”) as a lignocellulosic raw material for ultra-low-density hemp particleboard (ULHPB) with densities ranging from 213 to 309 kg/m3. The hurd was first milled and fractionated into three particle size categories, that is, fine (F), medium (M), and coarse (C). Twelve unique ULHPB variants were then fabricated comprising varying particle loadings from four particle size mixes, that is, 100% C, 100% M, 50%/50% CM, 25%/50%/25% CMF, and adhesive contents of bio-epoxy (EPX), phenol resorcinol formaldehyde (PRF), and emulsifiable methylene diphenyl diisocyanate (MDI), respectively. The panel assessments, conducted in accordance with the Australian reconstituted wood-based panels standard AS/NZS 1859.1 (2017), revealed a significant effect of particle dimension on most physico-mechanical properties. Furthermore, the resination method and pressing temperature controlled post-cure panel expansion and additional panel characteristics. Notably, MDI-ULHPB exhibited drastically different behavior and properties compared to EPX and PRF equivalents, demonstrating greater bending strength, stiffness, screw withdrawal strength, and dimensional stability. Importantly, all MDI variants conformed to the 15% thickness swelling limit for moisture resistant particleboard. Surface lamination of MDI-bonded ULHPB with sheets of aluminum, Masonite, and Kraft liner significantly improved the inherently low flexural properties, suggesting the potential suitability of ULHPB as a core layer in lightweight sandwich composite panels. The integration of agricultural by-products, such as hemp hurd, into engineered building materials presents a promising opportunity to mitigate the depletion of finite timber resources and aligns well with circular economy principles. Highlights • Utilizing agricultural residue as sustainable raw material in building products. • Hemp hurd enables ultra-low-density particleboard with thermosetting resins. • Coarse particle size mix enhances mechanical performance in panels. • Panel characteristics controlled by resination method and pressing temperature. • Lamination enhances functionality of lightweight hemp hurd sandwich panel.
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ItemNo Preview AvailableAdvancing enhanced wood manufacturing industries in Laos and Australia - Final Report(Australian Centre for International Agricultural Research (ACIAR), 2023-07-17)ACIAR invested in Lao PDR's plantation and wood products sector in 2005, with the third project, FST/2016/151 – Advancing enhanced wood manufacturing industries in Laos and Australia (VALTIP3), building on the results. The VALTIP3 project conducted research on plantation-wood value chains, mapping plantations, exploring actors like traders and women, developing innovative wood products, and implementing processing technologies. It also assessed policy, regulatory, and strategic settings in these areas. The projects built local capacity to meet the demand of plantation-wood processing companies in Laos for NUoL FFS graduates and government stakeholders seeking VALTIP3 team members' knowledge for policy changes.
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ItemA review of some aspects of goat meat quality: future research recommendations(CSIRO Publishing, 2023)The global goat meat sector is advancing and contributes to long-term food security, especially in meeting the protein demands of the growing human population in developing countries. Spanning all countries, Australia, is the largest exporter of goat meat, although it has negligible consumption. However, Australia does potentially have a secure future as an innovative, profitable, and resilient world leader in goat production, provided some challenges are addressed. These challenges facing the goat meat sector require suitable strategies and interventions for better profitability and acceptance of goat meat consumed in Australia and as an export product. Limited research on goat meat quality and the lack of an adequate grading system for goat meat quality are two of the major issues that need attention from the industry and researchers. Some of the most critical areas that need further research to enable growth of the goat meat industry are the influence of genetics and age of animals on meat quality, standardisation of the ageing period of various goat meat cuts, cooking innovations, consumer acceptance and sensory analysis of goat meat (both farmed and rangeland goats). This paper reviews the status of the goat meat sector and identifies the opportunities for the goat meat sector, particularly in Australia. In addition, we highlight several key issues requiring further research and interventions to enhance the growth of the goat meat industry.
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ItemInulin fructans - food applications and alternative plant sources: a review(WILEY, 2022-07-12)Fructans are water soluble, non‐digestible fructose polymers found as storage polysaccharides in certain plants. They are classified as inulin‐type, graminan‐type and branched‐type, while the former being the most extensively researched fructan type. Inulin fructans vary in different plants, with respect to the chain length, degree of polymerisation and molecular weight. Being one of the most versatile functional food ingredients, inulin fructans are well known for their unique bifidogenic and prebiotic properties as well as techno‐functional properties including fibre enhancing, fat and sugar replacing and viscosity and texture modifying attributes in food systems. Therefore, incorporation of inulin fructans into more frequently consumed dairy and non‐dairy products has become an emerging trend in the food industry. Despite the commercial manufacture of inulin fructans from chicory, a growing interest has emerged to extract this functional ingredient from inulin‐rich alternative plant sources including jerusalem artichoke, globe artichoke, yacon, burdock, asparagus species, garlic, agave and dandelion, which can potentially be good sources of inulin for food and nutraceutical applications in future. This review provides an in‐depth insight of inulin fructans including the chemistry, food applications and health benefits, and also giving special reference to alternative plant sources.
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ItemNo Preview AvailableEstimating forest above-ground biomass with terrestrial laser scanning: Current status and future directions(WILEY, 2022-06-09)Abstract Improving the global monitoring of above‐ground biomass (AGB) is crucial for forest management to be effective in climate mitigation. In the last decade, methods have been developed for estimating AGB from terrestrial laser scanning (TLS) data. TLS‐derived AGB estimates can address current uncertainties in allometric and Earth observation (EO) methods that quantify AGB. We assembled a global dataset of TLS scanned and consecutively destructively measured trees from a variety of forest conditions and reconstruction pipelines. The dataset comprised 391 trees from 111 species with stem diameter ranging 8.5 to 180.3 cm and AGB ranging 13.5–43,950 kg. TLS‐derived AGB closely agreed with destructive values (bias <1%, concordance correlation coefficient of 98%). However, we identified below‐average performances for smaller trees (<1,000 kg) and conifers. In every individual study, TLS estimates of AGB were less biased and more accurate than those from allometric scaling models (ASMs), especially for larger trees (>1,000 kg). More effort should go to further understanding and constraining several TLS error sources. We currently lack an objective method of evaluating point cloud quality for tree volume reconstruction, hindering the development of reconstruction algorithms and presenting a bottleneck for tracking down the error sources identified in our synthesis. Since quantifying AGB with TLS requires only a fraction of the efforts as compared to destructive harvesting, TLS‐calibrated ASMs can become a powerful tool in AGB upscaling. TLS will be critical for calibrating/validating scheduled and launched remote sensing initiatives aiming at global AGB mapping.