Mitigation of gaseous emissions from dairy livestock: A farm-level method to examine the financial implications.

Feeding the world's population while minimising the contribution of agriculture to climate change is one of the greatest challenges facing modern society. This challenge is particularly pronounced for dairy production where the carbon footprint of products and the mitigation costs are high, relative to other food stuffs. This paper reviews a number of mitigation measures that may be adopted by dairy farmers to reduce greenhouse gas emissions from their farms. A simulation model is developed to assess the cost-benefit of a range of mitigation measures. The model is applied to data from Ireland, a country with a large export-oriented dairy industry, for a range of farms including top, middle and bottom performing farms from a profitability perspective. The mitigation measures modelled included animal productivity, grass production and utilisation, better reproductive performance, early compact calving, reduced crude protein, decreased fertiliser N, protected urea, white clover, slurry tank cover and low emission slurry spreading (LESS). The results show that over half of the greenhouse gas abatement potential and most of the ammonia abatement potential were realised with cost-beneficial measures. Animal and feed-related measures that increased efficiency drove the abatement of GHG emissions. Low-emission slurry spreading was beneficial for the bottom and middle one-third of farms, while protected urea and reducing nitrogen use accounted for most of the ammonia abatement potential for the most profitable farms. Results showed that combining mitigation measures resulted in a decrease of 23%, 19%, and 12% in GHG emissions below 2020 levels for the bottom, middle, and top performing dairy farms, respectively. The findings imply that top dairy farms, that are already managed efficiently and optimally, may struggle to achieve the national and international GHG reduction targets with existing technologies and practices.

Comparing different pneumoperitoneum (12 vs. 15 mmHg) pressures with cytokine analysis to evaluate clinical outcomes in patients undergoing robotic-assisted laparoscopic radical cystectomy and intracorporeal robotic urinary diversion.

Background: Robotic cystectomy is the mainstay surgical intervention for treatment-refractory nonmuscle-invasive and muscle-invasive bladder cancer. However, paralytic ileus may complicate the postoperative recovery and may be a consequence of an inflammatory response associated with transient gut ischaemia. We have therefore investigated clinical, operative and inflammatory biomarker associations between paralytic ileus in the context of robotic cystectomy and intracorporeal ileal conduit urinary diversion. Methods: Prospective consective patients referred for robotic cystectomy were consented and included in the study, while patients >75 years old and converted to open procedure were excluded. The pneumoperitoneum pressure (PP) for carbon dioxide insufflation required to perform the procedure efficiently and safely was recorded (12 or 15 mmHg). We also recorded the postoperative days patients passed flatus and stools, whether they developed ileus, as well as other standard clinical and demographic data. The expression of select proinflammatory and anti-inflammatory cytokines was determined by multiplex analysis using a cytometric bead array with changes in profiles correlated with the pressures applied and with the existence of an ileus. Results: Twenty-seven patients were recruited, but only 20 were used in the study with 10 patients in each PP group. Seven patients were excluded all of whom had an extracorporeal ileal conduit formation. There were differences in the 40-min shorter operative time and 1 day shorter length of stay, as well as passing flatus 1 day and stools 1.5 days earlier in the 12 mmHg compared with the 15 mmHg group. More patients had ileus in the 15 mmHg group vs 12 mmHg group (30% vs. 10.0%). These were not statistically significant. Similarly, there were no statistical differences in the expression of proinflammatory cytokines at the two different pressures or between patient groups, but there were outliers, with the median indicating nonsymmetrical distribution. By comparison, anti-inflammatory cytokines showed some significant differences between groups, with IL-6 and IL-10 showing elevated levels postsurgery. No statistical difference was observed between pressures or the existence of an ileus, but the maximum levels of IL-6 and IL-10 detected in some patients reflect a pressure difference. Conclusions: The initial findings of this novel scientific study indicated a higher risk of paralytic ileus postrobotic cystectomy and robotic intracorporeal urinary diversion when a higher pressure of 15 mmHg is used compared with 12 mmHg. Although further studies are required to establish the linkage between cytokine profile expression, pressure and ileus, our initial data reinforces the advantages of lower pressure robotic cystectomy and intracorporeal urinary diversion in patient outcomes.

Influence of key factors on ammonia and nitrous oxide emission factors for excreta deposited by livestock and land-applied manure.

Ammonia (NH3) and nitrous oxide (N2O) emissions from livestock manure management have a significant impact on air quality and climate change. There is an increasing urgency to improve our understanding of drivers influencing these emissions. We analysed the DATAMAN ("DATAbase for MANaging greenhouse gas and ammonia emissions factors") database to identify key factors influencing (i) NH3 emission factors (EFs) for cattle and swine manure applied to land and (ii) N2O EFs for cattle and swine manure applied to land, and (iii) cattle urine, dung and sheep urine deposited during grazing. Slurry dry matter (DM) content, total ammoniacal nitrogen (TAN) concentration and method of application were significant drivers of NH3 EFs from cattle and swine slurry. Mixed effect models explained 14-59 % of the variance in NH3 EFs. Apart from the method of application, the significant influence of manure DM, manure TAN concentration or pH on NH3 EFs suggests mitigation strategies should focus on these. Identifying key factors influencing N2O EFs from manures and livestock grazing was more challenging, likely because of the complexities associated with microbial processes and soil physical properties impacting N2O production and emissions. Generally, significant factors were soil-related e.g. soil water content, pH, clay content, suggesting mitigations may need to consider the conditions of the receiving environment for manure spreading and grazing deposition. Total variability explained by terms in mixed effect model was on average 66 %, with the random effect 'experiment identification number' explaining, on average, 41 % of the total variability in the models. We suspect this term captured the effect of non-measured manure, soil and climate factors and any biases in application and measurement technique effects associated with individual experiments. This analysis has helped to improve our understanding of key factors of NH3 and N2O EFs for inclusion within models. With more studies over time, insights into the underlying processes influencing emissions will be further improved.

Comparison of ammonia emissions related to nitrogen use efficiency of livestock production in Europe.

The increasing global demand for food and the environmental effects of reactive nitrogen losses in the food production chain, increase the need for efficient use of nitrogen (N). Of N harvested in agricultural plant products, 80% is used to feed livestock. Because the largest atmospheric loss of reactive nitrogen from livestock production systems is ammonia (NH3), the focus of this paper is on N lost as NH3 during the production of animal protein. The focus of this paper is to understand the key factors explaining differences in Nitrogen Use Efficiency (NUE) of animal production among various European countries. Therefore we developed a conceptual framework to describe the NUE defined as the amount of animal-protein N per N in feed and NH3-N losses in the production of milk, beef, pork, chicken meat and eggs in The Netherlands, Switzerland, United Kingdom, Germany, Austria and Denmark. The framework describes how manure management and animal-related parameters (feed, metabolism) relate to NH3 emissions and NUE. The results showed that the animal product with the lowest NUE had the largest NH3 emissions and vice versa, which agrees with the reciprocal relationship between NUE and NH3 within the conceptual framework. Across animal products for the countries considered, about 20% of the N in feed is lost as NH3. The significant smallest proportion (12%) of NH3-N per unit of Nfeed is from chicken production. The proportions for other products are 17%, 19%, 20% and 22% for milk, pork, eggs and beef respectively. These differences were not significantly different due to the differences among countries. For all countries, NUE was lowest for beef and highest for chicken. The production of 1 kg N in beef required about 5 kg N in feed, of which 1 kg N was lost as NH3-N. For the production of 1 kg N in chicken meat, 2 kg N in feed was required and 0.2 kg was lost as NH3. The production of 1 kg N in milk required 4 kg N in feed with 0.6 kg NH3-N loss, the same as pork and eggs, but those needed 3 and 3.5 kg N in feed per kg N in product respectively. Except for beef, the differences among these European countries were mainly caused by differences in manure management practices and their emission factors, rather than by animal-related factors including feed and digestibility influencing the excreted amount of ammoniacal N (TAN). For beef, both aspects caused important differences. Based on the results, we encourage the expression of N losses as per N in feed or per N in product, in addition to per animal place, when comparing production efficiency and NUE. We consider that disaggregating emission factors into a diet/animal effect and a manure management effect would improve the basis for comparing national NH3 emission inventories.

Utilization of by-products from ethanol production as substrate for biogas production.

The aims of this work were to determine the specific biogas yields of steam-exploded sugarcane straw and bagasse as well as to estimate their energy potential under Brazilian conditions. Steam-explosion was carried out under different time and temperature conditions. The specific biogas yields were analyzed in batch-tests according to VDI 4630. Results have shown that steam-explosion pre-treatment increased the specific biogas yields of straw and bagasse significantly compared to the untreated material. The utilization of these by-products can contribute to 5% of the total energy consumption and thereby higher energy independence in Brazil. Further efforts in defining the optimum pretreatment conditions with steam-explosion as well as implementing this technology in large scale plants should be made.