Veterinary and Agricultural Sciences Collected Works - Research Publications
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ItemNo Preview AvailablePampered pets or poor bastards? The welfare of dogs kept as companion animals(ELSEVIER, 2022-06-01)
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ItemNo Preview AvailableHigh NH3 deposition in the environs of a commercial fattening pig farm in central south China(IOP Publishing Ltd, 2021-12-01)Abstract Intensive livestock production has been increasing, and has resulted in the emission of more than seven teragram per year of ammonia (NH3) in China in recent years. However, little is known about the fate of the emitted NH3, especially the dry deposition of NH3 in the environs of intensive animal farms. In this study, the spatial and temporal variations of NH3 deposition in the environs of an intensive fattening pig farm were investigated in the central south of China. NH3 concentrations were measured at sites situated 50, 100, 200, 300, and 500 m in the downwind direction from the farm each month from July 2018 to June 2019. The NH3 deposition was calculated based on a bidirectional NH3 exchange model. The monthly NH3 emissions from the pig farm were estimated based on the breeding stock. The annual average NH3 concentrations ranged from 1200 to 14 μg m−3 at the downwind sites within 500 m of the pig farm, exhibiting exponential decay as distance increased. Strong seasonality in NH3 deposition was observed, with the highest season being in the summer and lowest in the winter, and air temperature was found to be an important factor affecting this seasonal variation. The estimated monthly total dry deposition within 500 m of the pig farm ranged from 92 to 1400 kg NH3–N mo−1, which accounted for 4.1%–14% of the total monthly NH3 emissions from the pig farm. The estimated total NH3 emissions and NH3 deposition from the pig farm were 63 000 kg NH3–N yr−1 and 5400 kg NH3–N yr−1, respectively, with the annual average ratio of NH3 deposition to NH3 emission being 8.6%. This study found NH3 deposition around intensive pig farms is high, and determined it as a significant fate of the NH3 emitted from pig farms.
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ItemNo Preview AvailableImpact of hot weather on animal performance and genetic strategies to minimise the effect(CSIRO PUBLISHING, 2022-02-01)Dairy cows in Australia and New Zealand are generally kept outdoors, making them susceptible to weather variability and in particular heat stress. In this paper, we review (1) exploiting genetic variability to improve heat tolerance, (2) genotype by environment interactions, i.e. suitability of high merit cows to weather variability and (3) how novel phenotyping and genomics can help improve heat tolerance. Selection for heat tolerance is a permanent and cumulative strategy and especially useful in grazing situations where management practices, such as cooling mechanisms, are sometimes impractical. Australia was the first country in the world to release breeding values for heat tolerance in dairy cattle nationally in 2017. The breeding value captures genetic variation in the reduction of milk production traits with rising temperature and humidity. The breeding values have been validated in independent studies (in Victoria, Australia, and California, USA), showing that thermotolerant cows maintain a lower core body temperature under hot and humid conditions. Genotype by environment interactions for traits sensitive to heat is only a concern for farms in very extreme conditions and therefore affect only a small proportion of individuals (those in the extreme 5th percentile). Heat tolerance is a complex trait in that in addition to milk traits, health and fertility may also be affected. Next-generation heat tolerance breeding values may include sensor device information in addition to changes in milk composition, or other measurable biomarkers. This is especially useful when measured in genotyped female populations. Research into novel ways of measuring heat tolerance could transform the way we select for this trait and capture more of the complexity of this trait. To be successful in this area, multi-disciplinary collaboration among animal scientists is likely to facilitate this goal. Combining genomics, traditional and novel measures of heat tolerance with intermediate metabolic biomarkers and prioritised genetic variants could be a way to capture the complexity of thermotolerance in future heat tolerance breeding values. Finally, selecting cows that are resilient to variability in weather is feasible and heat tolerance is a good example of this.
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ItemNo Preview AvailableInterventions that influence animal-product consumption: A meta-review(Elsevier BV, 2022-06-01)
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ItemNo Preview AvailableIrrigation subsidies and their externalities(ELSEVIER, 2021-10-30)
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ItemNo Preview AvailableChemical pollution: A growing peril and potential catastrophic risk to humanity(PERGAMON-ELSEVIER SCIENCE LTD, 2021-05-12)Anthropogenic chemical pollution has the potential to pose one of the largest environmental threats to humanity, but global understanding of the issue remains fragmented. This article presents a comprehensive perspective of the threat of chemical pollution to humanity, emphasising male fertility, cognitive health and food security. There are serious gaps in our understanding of the scale of the threat and the risks posed by the dispersal, mixture and recombination of chemicals in the wider environment. Although some pollution control measures exist they are often not being adopted at the rate needed to avoid chronic and acute effects on human health now and in coming decades. There is an urgent need for enhanced global awareness and scientific scrutiny of the overall scale of risk posed by chemical usage, dispersal and disposal.
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ItemNo Preview AvailableAbsence of high priority critically important antimicrobial resistance in Salmonella sp. isolated from Australian commercial egg layer environments(ELSEVIER, 2021-01-16)The development of antimicrobial resistance in foodborne pathogens is a growing public health concern. This study was undertaken to determine the antimicrobial susceptibility of Salmonella enterica subspecies enterica isolated from the Australian commercial egg layer industry. S. enterica subspecies enterica (n=307) isolated from Australian commercial layer flock environments (2015-2018) were obtained from reference, research and State Government laboratories from six Australian states. All Salmonella isolates were serotyped. Antimicrobial susceptibility testing (AST) for 16 antimicrobial agents was performed by broth microdilution. Antimicrobial resistance genes and sequence types (STs) were identified in significant isolates by whole genome sequencing (WGS). Three main serotypes were detected, S. Typhimurium (n=61, 19.9%), S. Senftenburg (n=45, 14.7%) and S. Agona (n=37, 12.1%). AST showed 293/307 (95.4%) isolates were susceptible to all tested antimicrobial agents and all isolates were susceptible to amoxicillin-clavulanate, azithromycin, ceftiofur, ceftriaxone, ciprofloxacin, colistin, florfenicol, gentamicin, kanamycin and trimethoprim-sulfamethoxazole. Low levels of non-susceptibility were observed to streptomycin (2.3%, n=7), sulfisoxazole (2.0%, n=6), chloramphenicol (1.3%, n=4) and tetracycline (1.0%, n=3). Very low levels of non-susceptibility were observed to ampicillin (2/307; 0.7%) and cefoxitin (2/307; 0.7%). Two isolates (S. Havana and S. Montevideo), exhibited multidrug-resistant phenotypes to streptomycin, sulfisoxazole and tetracycline and possessed corresponding antimicrobial resistance genes (aadA4, aac(6')-Iaa, sul1, tetB). One S. Typhimurium isolate was resistant to ampicillin and tetracycline, and possessed both tetA and blaTEM-1B. WGS also identified these isolates as belonging to ST4 (S. Montevideo), ST578 (S. Havana) and ST19 (S. Typhimurium). The absence of resistance to highest priority critically important antimicrobials as well as the extremely low level of AMR generally among Australian commercial egg layer Salmonella isolates likely reflect Australia's conservative antimicrobial registration policy in food-producing animals and low rates of antimicrobial use within the industry.
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ItemRice paddy soils are a quantitatively important carbon store according to a global synthesis(Springer Science and Business Media LLC, 2021-12)Abstract Rice paddies account for ~9% or the world’s cropland area and are characterized by environmental conditions promoting soil organic carbon storage, methane emissions and to a lesser extent nitrous oxide emissions. Here, we synthesize data from 612 sites across 51 countries to estimate global carbon stocks in paddy soils and determine the main factors affecting paddy soil carbon storage. Paddy soils (0–100 cm) contain 18 Pg carbon worldwide. Paddy soil carbon stocks decrease with increasing mean annual temperature and soil pH, whereas mean annual precipitation and clay content had minor impacts. Meta-analysis shows that paddy soil carbon stocks can be increased through several management practices. However, greenhouse gas mitigation through paddy soil carbon storage is generally outweighed by increases in methane and nitrous oxide emissions. Our results emphasize the key role of paddies in the global carbon cycle, and the importance of paddy management in minimizing anthropogenic greenhouse gas emissions.