GrassGroTM simulation of pasture, animal performance and greenhouse emissions on low and high sheep productivity grazing systems: 1-year validation and 25-year analysis

Globally, there is a focus on reducing the absolute methane (CH4) and nitrous oxide emissions, and the emissions intensity (EI, kg CO2e/kg animal product) of livestock production. Increasing the productivity of mixed pasture systems has the potential to increase food (e.g., lamb) and textile fibre (e.g., wool) production while reducing the EI of those products from grazing livestock. The objective of this study was to quantify the differences in greenhouse gas (GHG) emissions and EI between sheep on Low (i.e., low sustainable stocking rate) and High (i.e., high sustainable stocking rate) productivity grazing systems (PGSs). Therefore, a replicated breeding-ewe trial on 18 paddocks was established across 2 - years. Three flocks on Low (3 × 16 ewes/flock) and High PGSs (3 × 32 ewes/flock) rotated across three land-classes and three paddocks per PGS. In year 1, the observed on-farm pasture quantity, quality, and botanical composition, together with lamb BW (kg), and daily CH4 production (DMP, g CH4/head per day) using Open Path Fourier Transformed Infrared (OP-FTIR) spectrometers data were measured. Subsequently, two simulations using GrassGroTM were conducted: (1) a 1-year GrassGroTM simulation that used the observed on-farm data to adjust parameters: date of mating, paddock fertility, and weight of mature ewes to validate GrassGroTM predictions to achieve accuracy and precision targets; and (2) a 25-year (1986-2011) simulation to analyse the effects of Low and High PGSs on sheep production and GHG emissions across a variable climate. The 1-year validation predictions fitted well with the observed on-farm data for: pasture biomass (kg/ha), DM digestibility (%), botanical composition (kg/ha), lamb (kg) product, and DMP (g CH4/head per day). The subsequent predicted results from the 25-year GrassGroTM simulation showed minimal effect of PGS on the mean DM intake (kg DM/day) or DMP for Low and High PGSs, but this was thought to be due to the biomass in both PGSs exceeding 1 500 kg DM/ha. The EI, over the 25-year simulation, on the High PGS was 16.5% lower than the Low PGS. Additional calculations of DMP were conducted using a recent global equation, giving estimates of DMP that closely matched the observed on-farm OP-FTIR DMP measurements, but these were lower than the GrassGroTM predictions and improved the accuracy and precision. It is concluded that in some pasture situations, managing pastures and stock numbers to intensify grazing systems can allow increased livestock production, without increasing daily CH4 emissions/head while substantially decreasing the EI of the animal products generated.

Perioperative administration of tranexamic acid in hip fracture surgery (The PATHS study): national audit of current practice

INTRODUCTION

Neck of femur fractures (NOFF) are associated with significant morbidity and mortality, exacerbated by anaemia. Evidence indicates tranexamic acid (TXA) administration in NOFF surgery reduces blood loss and transfusion requirements, without increasing complications. The aim of this study was to establish current TXA administration practice in patients undergoing surgery for NOFF in the UK.

METHODS

We conducted a multicentre prospective study within the UK over a two-week period in March 2019. Pre-, intra- and postoperative data were collected locally and analysed centrally.

RESULTS

Data for 917 patients were submitted from 66 institutions. Of those eligible, 48.0% received TXA perioperatively. Administration rates varied from 0 to 100%. Significantly greater numbers undergoing arthroplasty received TXA (57.6%) compared with internal fixation (38.4%, p<0.01). Some 15.2% of institutions had a protocol for TXA use in NOFF. Patients treated in these units were significantly more likely to receive TXA (86.7%) than those who were not (41.2% p<0.01). Of those receiving TXA, 92.3% were given 1g intravenously (IV) at anaesthetic administration.

CONCLUSIONS

Despite supportive evidence for its use, a wide variation in the administration of TXA between hospitals and procedures has been demonstrated. Administration rates were higher for arthroplasty than for fixation procedures. Most centres do not have a protocol guiding TXA administration. We recommend administration of 1g IV TXA perioperatively for patients undergoing NOFF surgery, where not contraindicated, unless future randomised controlled trials support an alternative regimen. We recommend units include their own locally agreed TXA policy within a written protocol for the care of NOFF patients.

768 Impact Of COVID-19 And BOAST Standards on Surgical Management of Upper Limb Injuries in A Large Teaching Hospital

Aim

During the first peak of the COVID-19 pandemic, the BOA recommended that upper limb surgery for trauma should be avoided if possible, or performed as day-case if unavoidable, to reduce the risk of COVID-19 related negative outcomes. This audit assessed compliance with recommendations and impact on proportion of injuries managed conservatively due to COVID-19 risks, inpatient stay duration, COVID-19 infections, and corrective surgical intervention rates.

Method

Data was collected for all referrals to orthopaedics for upper limb fractures/dislocations at a large NHS teaching hospital in the North West over a 10-week period from April 4^th to June 12^th. Follow up was performed to 6 months after date of injury. Care was audited against the “British Orthopaedic Association Standard in Trauma: Management of patient with urgent orthopaedic conditions and trauma during the coronavirus pandemic”.

Results

A total of 112 patients were referred. 76% of patients were discharged from Emergency Department, with surgery indicated in 48%. Of those, 11% (n = 6) were not operated on due to COVID-19 risks and 1 patient from this group (16.7%) has required secondary corrective surgery. Surgery was completed as day-case procedure in 50%. COVID-19 swabs were not taken in 46% of referrals, 50% had a negative test and 4% positive. No patients tested positive after discharge following treatment.

Conclusions

Few cases were managed conservatively based on COVID-19 risk, and only 1 patient has required secondary surgery. More upper limb injuries may be managed conservatively, as per BOAST standards, with day-case procedures better utilised as an alternative.

405 Radiological Analysis of Gentamicin Eluting Synthetic Bone Graft Substitute Used in The Management of Gustilo IIIB Open Fractures

Background

Management of traumatic bone void associated with Gustilo IIIB open fractures is challenging. Gentamicin eluting synthetic bone graft substitute (Cerament-G) had been recently utilised for the management of patients with these injuries. This study aims to assess radiological signs of Cerament-G remodelling.

Method

Retrospective data analysis of all patients admitted to our unit with IIIB open fractures who had Cerament-G applied as avoid filler. Postoperative radiographic images of the fracture site at 6-weeks, 3-months, 6-months and at the last follow-up were reviewed. The radiological signs of Cerament-G integration, percent of void healing, and bone cortical thickness at the final follow-up were assessed.

Results

34 patients met our inclusion criteria, mean age: 42 years. Mean follow-up time was 20 months. 59% of patients had excellent (&gt;90%) void filling, 26.4% of patients had 50-90% void filling, and 14.6% had &lt; 50% void filling. Normal bone cortical thickness was restored on AP and Lateral views in 55.8% of patients. No residual Cerement-G was seen on X-rays at the final follow-up in any of the patients.

Conclusions

Our results showed successful integration of Cerament-G with excellent void filling and normal cortical thickness achieved in more than half of the patients.

Field measurement of beef pen manure methane and nitrous oxide reveals a surprise for inventory calculations

Few data exist on direct greenhouse gas emissions from pen manure at beef feedlots. However, emission inventories attempt to account for these emissions. This study used a large chamber to isolate NO and CH emissions from pen manure at two Australian commercial beef feedlots (stocking densities, 13-27 m head) and related these emissions to a range of potential emission control factors, including masses and concentrations of volatile solids, NO, total N, NH, and organic C (OC), and additional factors such as total manure mass, cattle numbers, manure pack depth and density, temperature, and moisture content. Mean measured pen NO emissions were 0.428 kg ha d (95% confidence interval [CI], 0.252-0.691) and 0.00405 kg ha d (95% CI, 0.00114-0.0110) for the northern and southern feedlots, respectively. Mean measured CH emission was 0.236 kg ha d (95% CI, 0.163-0.332) for the northern feedlot and 3.93 kg ha d (95% CI, 2.58-5.81) for the southern feedlot. Nitrous oxide emission increased with density, pH, temperature, and manure mass, whereas negative relationships were evident with moisture and OC. Strong relationships were not evident between NO emission and masses or concentrations of NO or total N in the manure. This is significant because many standard inventory calculation protocols predict NO emissions using the mass of N excreted by the animal.

Coarse particulate matter emissions from cattle feedlots in Australia

Open cattle feedlots are a source of air pollutants that include particular matter (PM). Over 24 h, exposure to ambient concentrations of 50 microg m(-3) of the coarse-sized fraction PM (aerodynamic diameter <10 microm [PM(10)]) is recognized as a health concern for humans. The objective of our study was to document PM(10) concentration and emissions at two cattle feedlots in Australia over several days in summer. Two automated samplers were used to monitor the background and in-feedlot PM(10) concentrations. At the in-feedlot location, the PM(10) emission was calculated using a dispersion model. Our measurements revealed that the 24-h PM(10) concentrations on some of the days approached or exceeded the health criteria threshold of 50 microg m(-3) used in Australia. A key factor responsible for the generation of PM(10) was the increased activity of cattle in the evening that coincided with peak concentrations of PM(10) (maximum, 792 microg m(-3)) between 1930 and 2000 h. Rain coincided with a severe decline in PM(10) concentration and emission. A dispersion model used in our study estimated the emission of PM(10) between 31 and 60 g animal(-1) d(-1). These data contribute to needed information on PM(10) associated with livestock to develop results-based environmental policy.

Emissions of the indirect greenhouse gases NH3 and NOx from Australian beef cattle feedlots

Emissions of indirect greenhouse gases, notably the nitrogen gases ammonia (NH3) and the odd oxides of nitrogen (NOx), play important roles in the greenhouse story. Feedlots are intense, but poorly quantified, sources of atmospheric NH3 and although production of NOx is to be expected in feedlots, rates of NOx emission are virtually unknown. In the atmosphere, these gases are involved in several transformations, but eventually return to the earth in gaseous or liquid form and can then undergo further transformations involving the formation and emission of the direct greenhouse gas nitrous oxide (N2O). The IPCC Phase II guidelines estimate that indirect N2O emissions due to atmospheric deposition of N compounds formed from NH3 and NOx could be ~14% of the direct emissions from agricultural soils or from animal production systems. IPCC recommends that these indirect emissions be accounted for in making inventory estimates of N2O emission. This paper is a preliminary report of emissions of NH3 and NOx from two Australian feedlots determined with micrometeorological techniques. Emissions of nitrogen gases from both feedlots were dominated by emissions of NH3. The average NH3 emission rate over both feedlots in winter was 46 g N/animal.day, while that of NOx was less than 1% of that rate at 0.36 g N/animal.day. It was apparent that NH3 release was governed by the wetness of the surface. Rates of emission from the feedlot with the wetter surface were almost three times those from the other. The IPCC default emission factor for the combined emission of NH3 and NOx from livestock is 0.2 kg N/kg N excreted, but in our work, the emission factor was 0.59 kg N/kg N excreted. Potential emissions of N2O due to NH3 and NOx deposition were estimated to be of the same magnitude as the direct N2O emissions, the sum of direct and potential indirect amounting to ~3 g N2O-N/animal.day. If applied nationally, this would represent a contribution of N2O from Australian feedlots of 533Gg CO2-e or 2.2% of all Australian N2O emissions.

Finding extraterrestrial sites for thermophiles

Virtually our entire knowledge of the universe comes from two sorts of measurement of the electromagnetic radiation from the stars and galaxies within it; either their flux through relatively wide bandpasses (photometry), or measurements of the shape and wavelength of relatively narrow lines via spectroscopy. These techniques are now being used to discover planets outside our solar system, and perhaps in the next 10 years will begin to characterize them. If a serious search is to be made for extraterrestrial thermophiles, we need predictions for the effects of thermophiles on their host planets that are observable with these techniques. In this paper I shall outline what sorts of observation are likely to be used in the next 15 years for extra-solar planet work. All of the journal articles quoted here can be found through http://adsabs.harvard.edu/abstract_service.html, and often also accessed as preprints at http://uk.arxiv.org/form/astro%20ph?MULTI=form%20±%20interface.