Livestock forms an important component of global food production and is a significant contributor to anthropogenic greenhouse-gas (GHG) emissions. This paper reviews how whole farm-system modelling has been used to assess GHG mitigation strategies for livestock production. Whole farm-system modelling provides an effective and efficient means for quantifying the benefits farmers are delivering through changing farm management practices.

Studies of greenhouse gas emissions (GHGE) in agriculture rarely account for the variation that occurs due to seasonal conditions. This study quantified the effects of climate variability and stocking strategies on GHGE and profit of a northern Queensland beef herd. Moderate stocking rates had the lowest GHGE intensity and highest profit, supporting previous work that recommends similar stocking strategies in the region.

Emissions of the greenhouse gas nitrous oxide arise following deposition of excretal nitrogen from cattle grazing on pasture. Accurate measurement is challenging because the emissions can be very variable in time and space; paddock-scale methods can capture and integrate through this variability. We present here the first experiment to independently verify a paddock-scale emission method with a known emission of nitrous oxide. We show that emission is likely to be under-estimated using uncorrected vertical concentration-difference measurements.

Cattle emit methane, a greenhouse gas, which is usually measured in specialised facilities over 2 or more days. We have demonstrated that the measurement can be done in 1 day with less than 5% loss in accuracy. The resulting increase in throughput of the facilities means that more cattle can be measured for this important gas.

Methane, a major greenhouse gas emitted by livestock, requires robust methods of measurement in order to identify new and appropriate mitigation strategies. This study demonstrates that isolation within respiration chambers, the current most precise method of methane measurement in livestock, could underestimate emissions due to a reduction in feed intake. If changes in behaviour and physiology due to isolation stress are modelled, this would refine estimations of livestock greenhouse gas emissions that will help to find the most appropriate measures to mitigate climate change.

Methane emissions from ruminants are a significant contributor to climate change and are produced by archaeal methanogens. Due to their unusual metabolism, gene- and enzyme-based techniques can be used to develop methanogen-specific inhibitors, using strategies similar to those employed to develop anti-cancer drugs. We review previous research that has incorporated chemically defined inhibitors against methanogens and discuss the impacts on future control of ruminant methane emissions.

Livestock contributes to global warming by emission of greenhouse gases (GHGs). In the process of fermentation of feed in the fore stomach, dairy animals produce methane. Majority of dairy animals in developing countries are fed on rations imbalanced in nutrients. As a result, animals on such rations produce more methane per litre of milk. On feeding balanced rations, animals produce less enteric methane and manure nitrous oxide. Thus, balanced feeding could be a promising strategy for reducing GHGs emission intensity.

Methane production of sheep in pastoral systems is a major contributor to total greenhouse gasses produced in New Zealand. Elevated water-soluble carbohydrate concentrations, as in high sugar (HSG) and tetraploid (TRG) ryegrass, may affect rumen fermentation and reduce methane production per unit of intake, as found in this study for sheep fed HSG and TRG. However, the effect was not consistently associated with either cultivar and could not be attributed to higher forage water-soluble carbohydrate concentrations.

Dietary supplementation of 3-nitrooxypropanol (NOP) has been suggested as an effective strategy to lower enteric methane (CH₄) emissions from ruminants. Results from the present study further support the efficacy of NOP in lowering CH₄ emissions. Among various dose levels investigated in the present study, NOP supplemented at 100, 150 and 200 mg/kg DM was the most effective in decreasing CH₄ emissions in steers fed high-forage and high-grain diets, without inducing any negative effects on intake.

Methane emissions from ruminant livestock (cattle, buffalo, sheep and goat) were estimated at ~2.2 billion tonnes of carbon dioxide equivalent, accounting for ~80% of agricultural methane and 37% of the total anthropogenic methane emissions. The present study was designed to evaluate the effects of plants as methane inhibitors in growing buffaloes. Methane emission was inhibited by ~10–18% in the supplemented groups. Further, long-term experiments should be conducted to validate these findings before they can be recommended for use at a field level.

Six different herbal additives were evaluated in vitro using rumen liquor inoculum sourced from cattle and buffalo. The herbal additives influenced differently the in vitro ruminal microbial production efficiency and methane-inhibitory attributes. Further, the response of the herbal additives was different when incubated in rumen inoculum from cattle versus buffalo, indicating the importance of the species of the donor animal for such in vitro studies. Additionally, this may have significant implications in practical feeding situations targeting methane-reduction strategies.

Previous work has shown canola and wheat have potential as dual-purpose crops to support animal liveweight gain and grain production in animals other than dairy heifers. Limited information is available regarding the use of canola and wheat to support dairy heifer production and its effect on environment sustainability. This study investigated liveweight gain and urinary nitrogen excretion of dairy heifers grazing canola and wheat in comparison to perennial ryegrass-white clover pasture. The results indicate that canola and wheat can sustain heifer liveweight gain, while potentially reducing nitrous oxide emissions and nitrate leaching compared with pasture.

CH₄ and N₂O emissions from bovine dung-N are linearly correlated with faeces weight. N₂O emission factor of urine is reduced with urine volume. N deposited as urine is a much greater N₂O source than is faeces-N.

In Australia, animal excreta deposited onto pasture by grazing livestock is a major source of nitrous oxide, a potent greenhouse gas. Field studies found that emissions of nitrous oxide from excreta could be reduced by up to 59% by the application of the chemical inhibitor, nitrapyrin. Nitrapyrin was found to be an effective tool in reducing emissions from dung, urine and dairy sludge and was most effective on wet soils.

The greenhouse gas methane can be absorbed or emitted by soil while cattle wastes deposited onto the soil can be a source. In field studies, the effect of applications to pasture of dung and dairy sludge on net methane emissions to the atmosphere were examined. Measured emissions were mostly lower than those currently used in the current Australian estimates for emissions from dairy cow dung in temperate Australia.

Genome association studies for meat quality and carcass traits have identified genes and markers of major relevance for modern pig breeding industries. We have validated significant markers for meat quality and carcass traits with meta-analysis. Further, we developed gene network from GWAS that identified key transcription factors, gene-gene interactions and molecular pathways contributing to understanding the molecular genetic mechanisms underlying these traits in pigs.

The large intestine is a part of the gastrointestinal tract of pigs that is the most colonised by bacteria and its proper function is crucial for the maintenance of animal welfare and performance. Activity and composition of bacterial flora may be changed by feed additives such as inulin. Our results indicate that inulin, regardless of dietary level and degree of polymerisation, does not stimulate beneficial bacteria and immune system of the large intestine of young pigs.

Dietary restriction result in accelerated body growth in pigs during re-feeding, but it is not clear whether this phenomenon is due to changes in metabolic hormones, lipid deposition or protein metabolism. Effect of dietary protein restriction on the body growth and blood content of some metabolic hormones as markers of lipid or protein metabolism was studied. During the re-feeding, increased daily weight gains and concentrations of plasma leptin and urea nitrogen were observed, indicating greater lipid deposition and protein breakdown.

This study examined risk factors for dystocia, which is a major cause of lamb deaths. Dystocia increased with ewe age and for low birthweights was associated with increased litter size. Low birthweight dystocia may be a different condition from dystocia with high birthweight.

Adjusting the porosity of beddings can improve their ability to produce heat. The type of fungal-residue media has no effect on the growth performance of pigs. Smaller bedding granules may lead to pig cough. Fungal-residue bedding can partly replace sawdust in bedding. Bedding added 45% fungal residue can improve the welfare of pigs during winter.

For science to be effectively valorised in practise, stakeholders should be part of the research process. In this study, a management problem in pig production was analysed with stakeholders, which led to guidelines on how to perform such a process. These guidelines can well be considered in any research effort aiming at practical implementation of its results.

This study completed a life cycle assessment of energy, water and land occupation from pork production, covering supply chains and the national herd. Impacts arose predominantly from feed production, highlighting the importance of system efficiency, and particularly the feed conversion ratio for reducing resource use and environmental impacts. Changes to housing and improvements to manure management offer substantial opportunities for reducing the resource use intensity of pork.

A very high n-6 : n-3 ratio, as is found in today’s Western diets, promotes the pathogenesis of many diseases in consumers. The results of our study indicate that the recommended n-6 : n-3 polyunsaturated fatty acid ratio in turkey breast meat may be easily reached if birds are fed 2.5% flaxseed oil for the last 3 weeks before slaughter. Therefore, such a feeding program with a relatively low application of dietary flaxseed oil could be considered a suitable delivery vehicle for health-promoting fatty acids.