Assessing Resilience of Pasture Production to Climatic Changes

Increasing temperatures and atmospheric carbon dioxide (CO2) concentrations, together with changes to rainfall patterns, will influence seasonal pasture production; however climate change projections for south eastern Australia are uncertain (CSIRO and BoM 2007). Despite this, climate change impact assessments generally rely on specific climate projections, but in this study an alternative approach was developed to test the resilience of production to incremental changes in climate

Construction of a "mutagenesis cartridge" for poliovirus genome-linked viral protein: Isolation and characterization of viable and nonviable mutants

By following a strategy of genetic analysis of poliovirus, we have constructed a synthetic "mutagenesis cartridge" spanning the genome-linked viral protein coding region and flanking cleavage sites in an infectious cDNA clone of the type 1 (Mahoney) genome. The insertion of new restriction sites within the infectious clone has allowed us to replace the wild-type sequences with short complementary pairs of synthetic oligonucleotides containing various mutations. A set of mutations have been made that create methionine codons within the genome-linked viral protein region. The resulting viruses have growth characteristics similar to wild type. Experiments that led to an alteration of the tyrosine residue responsible for the linkage to RNA have resulted in nonviable virus. In one mutant, proteolytic processing assayed in vitro appeared unimpaired by the mutation. We suggest that the position of the tyrosine residue is important for genome-linked viral protein function(s)

The Use of Long-Term Modelling in Analysing N\u3csub\u3e2\u3c/sub\u3eO Abatement Strategies in Dairy Pastures

Concerns about the environmental impact of nitrogen (N) losses in Australia, in particular, nitrous oxide emissions are related to the rapid increase in N application on dairy pastures. Computer modelling is the most suitable method available to assess the potential of best management practices (BMP) to reduce field losses, as direct field measurements are frequently limited by the short term nature of many field trials

Modelling Adaptation and Mitigation Strategies for Southern Livestock Industries of Australia

Climate change will impact on the Australian grazing industries both through mitigation policies and the impact of warmer temperatures, increased atmospheric CO2 and changed rainfall patterns (Cullen et al. 2009; Eckard et al. 2010). Mechanistic models are useful tools to inform our understanding of the complex interactions between future climates and the soil, plant, animal and management in livestock production systems. This paper summarises the results of a number of whole farm systems modelling studies investigating likely impacts of climate change, adaptation options and emissions implications for livestock production in southern Australia

Modified approach to estimating daily methane emissions of dairy cows by measuring filtered eructations during milking

The aim of this study was to compare metrics for quantifying enteric methane (CH4) emissions from individual cows during milking using frequent spot measurements and peak analysis methods. An infrared gas analyser was used to measure the CH4 emitted by cows, and eructation peaks were identified using a Signal Processing Toolbox provided by Matlab. CH4 emissions were quantified by gas peak height, peak amplitude and average concentration, and were expressed in grams per day and CH4 yield (grams per kilogram of dry matter intake (DMI)). Peak analysis measurements of CH4 were obtained from 36 cows during 2,474 milkings, during which cows were fed a ration containing between 39 and 70 % forage. Spot measurements of CH4 were compared to a separate dataset of 196 chamber CH4 records from another group of 105 cows, which were fed a ration containing between 25 and 80 % forage. The results showed that the metrics of CH4 peak height and CH4 peak amplitude demonstrated similar positive relationships between daily CH4 emissions and DMI (both r = 0.37), and a negative relationship between CH4 yield and DMI (r = -0.43 and -0.38 respectively) as observed in the chamber measurements (r = 0.57 for daily emissions and r = -0.40 for CH4 yield). The CH4 metrics of peak height and peak amplitude were highly repeatable (ranging from 0.76 to 0.81), comparable to the high repeatability of production traits (ranging from 0.63 to 0.99) and were more repeatable than chamber CH4 measurements (0.31 for daily emissions and 0.03 for CH4 yield). This study recommends quantifying CH4 emissions from the maximum amplitude of an eructation

Nitrogen Balances in High Rainfall, Temperate Dairy Pastures of South Eastern Australia

Nitrogen (N) fertilizer use on dairy pastures in south eastern Australia has increased exponentially over the past 15 years, causing increasing environmental concerns. Volatilisation, denitrification and leaching of N were measured for one year (1998-1999) in pastures receiving no N fertilizer (grass/clover), or 200 kg N/ha applied as urea (46%N) or ammonium nitrate (34.5%N). Nitrogen balances were calculated for each treatment. Significantly more N was lost through volatilisation and denitrification when N was applied as urea compared to ammonium nitrate. Nitrate leaching losses were significantly greater with the application of N fertilizer, although the maximum loss was only 4.1 kg N/ha due to low rainfall between May and September. Nitrogen balances were -15, +87 and +82 kg N/ha per year for the grass/clover, 200 kg N/ha urea and 200 kg N/ha ammonium nitrate treatments, respectively. Given the large range in N losses and balances, there is opportunity for improving the N efficiency in dairy pastures, through lower stocking rates and more tactical use of grain and N fertilizer

Third WHO Global Consultation on regulatory requirements for xenotransplantation clinical trials, Changsha, Hunan, China December 12-14, 2018: "The 2018 Changsha Communiqué" The 10-Year Anniversary of The International Consultation on Xenotransplantation

After feedback from the working parties, the final session focused on drafting proposed revisions of the WHO documents, and resulted in the formulation of the draft “Third WHO Global Consultation on Regulatory Requirements for Xenotransplantation Clinical Trials, The 2018 Changsha Communiqué.” This draft was submitted to WHO in February 2019 for WHO and World Health Assembly consideration. If approved, the 2018 Changsha Communiqué will then be posted on the websites of WHO, IXA, and TTS, and published in Xenotransplantation. This report includes summaries of the various sessions, followed by the abstracts of invited speakers from the update sessions