Background: Since January 1, 2016 2358 people have died from opioid poisoning in Alberta. Buprenorphine/naloxone (bup/nal) is the recommended first line treatment for opioid use disorder (OUD) and this treatment can be initiated in emergency departments and urgent care centres (EDs). Aim Statement: This project aims to spread a quality improvement intervention to all 107 adult EDs in Alberta by March 31, 2020. The intervention supports clinicians to initiate bup/nal for eligible individuals and provide rapid referrals to OUD treatment clinics. Measures & Design: Local ED teams were identified (administrators, clinical nurse educators, physicians and, where available, pharmacists and social workers). Local teams were supported by a provincial project team (project manager, consultant, and five physician leads) through a multi-faceted implementation process using provincial order sets, clinician education products, and patient-facing information. We used administrative ED and pharmacy data to track the number of visits where bup/nal was given in ED, and whether discharged patients continued to fill any opioid agonist treatment (OAT) prescription 30 days after their index ED visit. OUD clinics reported the number of referrals received from EDs and the number attending their first appointment. Patient safety event reports were tracked to identify any unintended negative impacts. Evaluation/Results: We report data from May 15, 2018 (program start) to September 31, 2019. Forty-nine EDs (46% of 107) implemented the program and 22 (45% of 49) reported evaluation data. There were 5385 opioid-related visits to reporting ED sites after program adoption. Bup/nal was given during 832 ED visits (663 unique patients): 7 visits in the 1st quarter the program operated, 55 in the 2nd, 74 in the 3rd, 143 in the 4th, 294 in the 5th, and 255 in the 6th. Among 505 unique discharged patients with 30 day follow up data available 319 (63%) continued to fill any OAT prescription after receiving bup/nal in ED. 16 (70%) of 23 community clinics provided data. EDs referred patients to these clinics 440 times, and 236 referrals (54%) attended their first follow-up appointment. Available data may under-report program impact. 5 patient safety events have been reported, with no harm or minimal harm to the patient. Discussion/Impact: Results demonstrate effective spread and uptake of a standardized provincial ED based early medical intervention program for patients who live with OUD.

Introduction: Determining fluid status prior to resuscitation provides a more accurate guide for appropriate fluid administration in the setting of undifferentiated hypotension. Emergency Department (ED) point of care ultrasound (PoCUS) has been proposed as a potential non-invasive, rapid, repeatable investigation to ascertain inferior vena cava (IVC) characteristics. Our goal was to determine the feasibility of using PoCUS to measure IVC size and collapsibility. Methods: This was a planned secondary analysis of data from a prospective multicentre international study investigating PoCUS in ED patients with undifferentiated hypotension. We prospectively collected data on IVC size and collapsibility using a standard data collection form in 6 centres. The primary outcome was the proportion of patients with a clinically useful (determinate) scan defined as a clearly visible intrahepatic IVC, measurable for size and collapse. Descriptive statistics are provided. Results: A total of 138 scans were attempted on 138 patients; 45.7% were women and the median age was 58 years old. Overall, one hundred twenty-nine scans (93.5%; 95% CI 87.9 to 96.7%) were determinate. 131 (94.9%; 89.7 to 97.7%) were determinate for IVC size, and 131 (94.9%; 89.7 to 97.7%) were determinate for collapsibility. Conclusion: In this analysis of 138 ED patients with undifferentiated hypotension, the vast majority of PoCUS scans to investigate IVC characteristics were determinate. Future work should include analysis of the value of IVC size and collapsibility in determining fluid status in this group.

Quaternary processes and environmental changes are often difficult to assess in remote subantarctic islands due to high surface erosion rates and overprinting of sedimentary products in locations that can be a challenge to access. We present a set of high-resolution, multichannel seismic lines and complementary multibeam bathymetry collected off the eastern (leeward) side of the subantarctic Auckland Islands, about 465 km south of New Zealand's South Island. These data constrain the erosive and depositional history of the island group, and they reveal an extensive system of sediment-filled valleys that extend offshore to depths that exceed glacial low-stand sea level. Although shallow, marine, U-shaped valleys and moraines are imaged, the rugged offshore geomorphology of the paleovalley floors and the stratigraphy of infill sediments suggests that the valley floors were shaped by submarine fluvial erosion, and subsequently filled by lacustrine, fjord, and fluvial sedimentary processes.

Tree-ring reconstructions of temperature often target trees at altitudinal or latitudinal tree line where annual growth is broadly expected to be limited by and respond to temperature variability. Based on this principal, regions with sparse tree line would seem to be restricted in their potential to reconstruct past temperatures. In the northeastern United States, there are only two published temperature reconstructions. Previous work in the region reconstructing moisture availability, however, has shown that using a greater diversity of species can improve reconstruction model skill. Here, we use a network of 228 tree-ring records composed of 29 species to test the hypothesis that an increase in species diversity among the pool of predictors improves reconstructions of past temperatures. Chamaecyparis thyoides alone explained 31% of the variability in observed cool-season minimum temperatures, but a multispecies model increased the explained variance to 44%. Liriodendron tulipifera, a species not previously used for temperature reconstructions, explained a similar amount of variance as Chamaecyparis thyoides (12.9% and 20.8%, respectively). Increasing the species diversity of tree proxies has the potential for improving reconstruction of paleotemperatures in regions lacking latitudinal or elevational tree lines provided that long-lived hardwood records can be located.

Introduction: Les patients ayant un retour de circulation spontanée (RCS) durant la phase préhospitalière de leur réanimation suite à un arrêt cardiaque extrahospitalier (ACEH) ont un meilleur taux de survie que ceux n'en ayant pas. La durée des efforts de réanimation avant l'initiation d'un transport ne varie généralement pas en fonction du rythme initial observé. Cette étude vise à comparer la durée des manœuvres de réanimation nécessaire afin de générer la majorité des RCS préhospitaliers et des RCS préhospitaliers menant à une survie en fonction du rythme initial. Methods: La présente étude de cohorte a été réalisée à partir des bases de données collectées de la Corporation d'Urgences-santé dans la région de Montréal entre 2010 et 2015. Les patients avec un ACEH d'origine médicale ont été inclus. Les patients dont l'ACEH était témoigné par les paramédics ont été exclus, tout comme ceux dont le rythme initial était inconnu. Nous avons comparé entre les groupes (rythme défibrillable [RD], activité électrique sans pouls [AESP] et asystolie) les taux de RCS préhospitalier et le temps nécessaires pour obtenir une majorité des RCS préhospitaliers et des RCS préhospitaliers menant à une survie. Results: Un total de 6002 patients (3851 hommes et 2151 femmes) d'un âge moyen de 52 ans ( ±10) ont été inclus dans l’étude, parmi lesquels 563 (9%) ont survécu jusqu’à leur congé hospitalier et 1310 (22%) ont obtenu un RCS préhospitalier. Un total de 1545 (26%) patients avaient un RD, 1654 (28%) une AESP et 2803 (47%) une asystolie. Les patients avec un RD ont obtenu plus fréquemment un RCS préhospitalier et un RCS préhospitalier menant à une survie que les patients avec une AESP qui eux même avaient un meilleur pronostic que ceux avec une asystolie initial (777 patients [55%] vs 385 [23%] vs 148 [5%], p < 0,001; 431 [28%] vs 85 [5%] vs 7 [0,2%], p < 0,001, respectivement). Les RCS survenaient également plus rapidement lorsque le rythme initial était un RD (13 minutes [ ±12] vs 18 [ ±13] vs 25 [ ±12], p < 0,001). Cependant, une période de réanimation plus longue était nécessaire afin d'obtenir 95% des RCS préhospitaliers menant à une survie pour les patients avec un RD (26 minutes vs 21 minutes vs 21 minutes). Conclusion: Les patients avec un rythme initial défibrillable suite à leur ACEH sont à meilleur pronostic. Il serait envisageable de transporter plus rapidement vers l'hôpital les patients avec une AESP ou une asystolie que ceux avec un rythme défibrillable si l'arrêt des manœuvres n'est pas envisagé.

Background: Buprenorphine/naloxone (bup/nal) is a partial opioid agonist/antagonist and recommended first line treatment for opioid use disorder (OUD). Emergency departments (EDs) are a key point of contact with the healthcare system for patients living with OUD. Aim Statement: We implemented a multi-disciplinary quality improvement project to screen patients for OUD, initiate bup/nal for eligible individuals, and provide rapid next business day walk-in referrals to addiction clinics in the community. Measures & Design: From May to September 2018, our team worked with three ED sites and three addiction clinics to pilot the program. Implementation involved alignment with regulatory requirements, physician education, coordination with pharmacy to ensure in-ED medication access, and nurse education. The project is supported by a full-time project manager, data analyst, operations leaders, physician champions, provincial pharmacy, and the Emergency Strategic Clinical Network leadership team. For our pilot, our evaluation objective was to determine the degree to which our initiation and referral pathway was being utilized. We used administrative data to track the number of patients given bup/nal in ED, their demographics and whether they continued to fill bup/nal prescriptions 30 days after their ED visit. Addiction clinics reported both the number of patients referred to them and the number of patients attending their referral. Evaluation/Results: Administrative data shows 568 opioid-related visits to ED pilot sites during the pilot phase. Bup/nal was given to 60 unique patients in the ED during 66 unique visits. There were 32 (53%) male patients and 28 (47%) female patients. Median patient age was 34 (range: 21 to 79). ED visits where bup/nal was given had a median length of stay of 6 hours 57 minutes (IQR: 6 hours 20 minutes) and Canadian Triage Acuity Scores as follows: Level 1 – 1 (2%), Level 2 – 21 (32%), Level 3 – 32 (48%), Level 4 – 11 (17%), Level 5 – 1 (2%). 51 (77%) of these visits led to discharge. 24 (47%) discharged patients given bup/nal in ED continued to fill bup/nal prescriptions 30 days after their index ED visit. EDs also referred 37 patients with OUD to the 3 community clinics, and 16 of those individuals (43%) attended their first follow-up appointment. Discussion/Impact: Our pilot project demonstrates that with dedicated resources and broad institutional support, ED patients with OUD can be appropriately initiated on bup/nal and referred to community care.

Introduction: Les patients dont l'arrêt cardiaque extrahospitalier (ACEH) n'a pas été témoigné sont généralement exclus des protocoles de réanimation par circulation extracorporelle puisque le délai avant l'initiation de leur réanimation est inconnu. Il a été proposé que la présence d'un rythme initial défibrillable (RD) est fortement suggestif une très courte période avant l'initiation des manœuvres de réanimation. La présente étude vise à décrire l'association entre la durée avant l'initiation de la réanimation et la présence d'un RD chez des patients souffrant d'un ACEH. Methods: Cette étude de cohorte a été réalisée à partir des bases de données collectées de la Corporation d'Urgences-santé dans la région de Montréal entre 2010 et 2015. Les patients dont l'arrêt était témoigné, mais dont les témoins n'ont pas entamé de manœuvres de réanimation, ont été inclus. Nous avons également inclus les patients dont l'arrêt était témoigné par les paramédics comme groupe contrôle (durée avant l'initiation de la réanimation = 0 minute). Les patients avec un retour de circulation spontanée avant l'arrivée des services préhospitaliers ont été exclus, tout comme ceux dont le rythme initial était inconnu. Nous avons décrit l’évolution de la proportion de chacun des rythmes et construit une régression logistique multivariée ajustant pour les variables sociodémographiques et cliniques pertinentes. Results: Un total de 1751 patients (1173 hommes et 578 femmes) d'un âge moyen de 69 ans (±16) ont été inclus dans l'analyse principale, parmi lesquels 603 (34%) avaient un RD. Un total de 663 autres patients ont vu leur ACEH témoigné directement par les paramédics. Un plus court délai avant l'initiation des manœuvres est associé à la présence d'un RD (rapport de cotes ajusté = 0,97 [intervalle de confiance à 95% 0,94-0,99], p = 0,016). Cependant, cette relation n'est pas linéaire et la proportion de RD ne diminue pas avant notablement jusqu’à ce que 15 minutes s’écoulent avant le début de la réanimation (0 min = 35%, 1-5 min = 37%, 5-10 min = 35%, 10-15 min = 34%, +de 15 min = 16%). Conclusion: Bien que la proportion de patients avec un RD diminue lorsque le délai augmente avant l'initiation des manœuvres, cette relation ne semble pas linéaire. La baisse principale de la proportion de patients avec RD semble se produire suite à la quinzième minute de délai avant le début de la réanimation.

Introduction: La réanimation par circulation extracorporelle (R-CEC) permet potentiellement d'améliorer la survie de patients souffrant d'un arrêt cardiaque extrahospitalier (ACEH) réfractaire aux traitements habituels. Cette technique, se pratiquant généralement en centre hospitalier (CH), doit être réalisée le plus précocement possible. Un transport vers le CH en temps opportun est donc nécessaire. Cette étude vise à décrire la durée nécessaire des manœuvres de réanimation préhospitalières afin d'optimiser le moment du départ vers le CH dans le but d'obtenir un maximum de retour de circulation spontanée (RCS) préhospitalier. Methods: La présente étude de cohorte a été réalisée à partir des bases de données collectées de la Corporation d'Urgences-santé dans la région de Montréal entre 2010 et 2015. Les patients éligibles à une R-CEC selon les critères locaux ont été inclus (<65 ans, rythme initial défibrillable, arrêt témoigné avec réanimation par un témoin). Les patients ayant eu un arrêt devant les paramédics ont été exclus, tout comme ceux avec un RCS avant l'arrivée des services préhospitaliers. Nous avons calculé la sensibilité et la spécificité à différents seuils afin de prédire un RCS préhospitalier et une survie au congé hospitalier. Une courbe ROC a également été construite. Results: Un total de 236 patients (207 hommes et 29 femmes) d'un âge moyen de 52 ans (±10) ont été inclus dans l’étude, parmi lesquels 93 (39%) ont survécu jusqu’à leur congé hospitalier et 136 (58%) ont obtenu un RCS préhospitalier. Le délai moyen avant leur RCS était de 13 minutes (±10). Plus de 50% des survivants avaient eu un RCS moins de 8 minutes après l'initiation des manœuvres de réanimation par les intervenants préhospitaliers, et plus de 90% avant 24 minutes. Plus de 50% de tous les RCS survenaient dans les 10 premières minutes de réanimation et plus de 90% dans les 31 premières minutes. La courbe ROC montrait visuellement que le délai avant le RCS maximisant la sensibilité et la spécificité pour prédire la survie chez ces patients était à 22 minutes (Sensibilité = 90%, spécificité = 78%; aire sous la courbe = 0,89 [intervalle de confiance à 95% 0,84-0,93]). Conclusion: Le départ vers le CH pourrait être considéré pour ces patients entre 8 et 24 minutes après l'initiation des manœuvres. Une période de réanimation de 22 minutes semble être le meilleur compromis à cet égard.

Introduction: Parmi les patients souffrant d'un arrêt cardiaque extrahospitalier (ACEH), ceux ayant un retour de circulation spontanée (RCS) durant la phase préhospitalière de leur réanimation ont un meilleur taux de survie. Il est plausible que les patients ayant un RCS plus précocement durant leur réanimation préhospitalière aient de meilleur taux de survie que les patients ayant un RCS plus tardif. Cette étude visait à décrire l'association entre la survie et la durée de la réanimation par les paramédics avant le RCS préhospitalier. Methods: La présente étude de cohorte a été réalisée à partir des bases de données collectées de la Corporation d'Urgences-santé dans la région de Montréal entre 2010 et 2015. Tous les patients adultes avec un RCS préhospitalier suite à un ACEH d'origine médicale ont été inclus. Les patients ayant eu un arrêt devant les paramédics ont été exclus, tout comme ceux avec un RCS avant l'arrivée des services préhospitaliers. L'association entre la survie et le temps de réanimation avant le RCS a été évaluée à l'aide d'une régression logistique multivariée ajustant pour les variables sociodémographiques et cliniques pertinentes (âge, sexe, rythme initial, heure de l'appel initial, arrêt témoigné, manœuvre par témoin, présence de premiers répondants ou de paramédics de soins avancés, délai avant l'arrivée des intervenants préhospitaliers). Results: Un total de 1194 patients (818 hommes et 376 femmes) d'un âge moyen de 64 ans ( ±17) ont été inclus dans l’étude, parmi lesquels 433 (36%) ont survécu jusqu’à leur congé hospitalier. Le délai moyen avant leur RCS était de 17 minutes ( ±12). Nous avons observé une association indépendante entre la survie au congé hospitalier et le délai avant le RCS préhospitalier (rapport de cotes ajusté = 0,91 [intervalle de confiance à 95% 0,89-0,92], p < 0,001). Plus de 50% des survivants avaient obtenu un RCS moins de 9 minutes après l'initiation des manœuvres de réanimation par les intervenants préhospitaliers, et plus de 95% avant 26 minutes. Aucun (0%) des 17 patients ayant eu un RCS plus de 56 minutes après l'initiation de la réanimation préhospitalière n'a survécu. Conclusion: Un RCS précoce semble être un facteur de bon pronostic parmi les patients souffrant d'un ACEH. La majorité des patients avec un RCS préhospitalier allant survivre à leur hospitalisation ont obtenus leur RCS dans les 9 minutes suivant l'initiation des manœuvres de réanimation.

Effective treatment of maternal antenatal depression may ameliorate adverse neurodevelopmental outcomes in offspring. We performed two follow-up rounds of children at age 2 and age 5 whose mothers had received either specialized cognitive-behavioural therapy or routine care for depression while pregnant. Of the original cohort of 54 women, renewed consent was given by 28 women for 2-year follow-up and by 24 women for 5-year follow-up. Child assessments at the 2-year follow-up included the Parenting Stress Index (PSI), Bayley Scales of Infant Development (BSID-III) and the Child Behaviour Checklist (CBCL). The 5-year follow-up included the Wechsler Preschool and Primary Scales of Intelligence (WPPSI-III) and again the CBCL. Treatment during pregnancy showed significant benefits for children’s development at age 2, but not at age 5. At 2 years, intervention effects were found with lower scores on the PSI Total score, Parent Domain and Child domain (d=1.44, 1.47, 0.96 respectively). A non-significant trend favoured the intervention group on most subscales of the CBCL and the BSID-III (most notably motor development: d =0.52). In contrast, at 5-year follow-up, no intervention effects were found. Also, irrespective of treatment allocation, higher depression or anxiety during pregnancy was associated with higher CBCL and lower WPPSI-III scores at 5 years. This is one of the first controlled studies to evaluate the long-term effect of antenatal depression treatment on infant neurodevelopmental outcomes, showing some benefit. Nevertheless, caution should be taken interpreting the results because of a small sample size, and larger studies are warranted.

Introduction: Patients suffering from out-of-hospital cardiac arrest (OHCA) with an initial shockable rhythm (ventricular tachycardia or ventricular fibrillation) have higher odds of survival than those suffering from non-shockable rhythm (asystole or pulseless electrical activity). Because of that prognostic significance, patients with an initial non-shockable rhythm are often not considered for advanced resuscitation therapies such as extracorporeal resuscitation. However, the prognostic significance of the conversion to a shockable rhythm from an initially non-shockable rhythm remains uncertain. This study aimed to determine the degree of association between the conversion (or not) of a non-shockable rhythm to a shockable rhythm and resuscitation outcomes in patients with OHCA. It was hypothesized that such a conversion would be associated with a higher survival to discharge. Methods: The present study used a registry of adult OHCA between 2010 and 2015 in Montreal, Canada. Adult patients with non-traumatic OHCA and an initial non-shockable rhythm were included. The primary outcome measure was survival to hospital discharge, and the secondary outcome measure was prehospital return of spontaneous circulation (ROSC). The associations of interest were evaluated with univariate logistic regressions and multivariate models controlling for demographic and clinical variables (e.g. age, gender, type of initial non-shockable rhythm, witnessed arrest, bystander cardiopulmonary resuscitation). Assuming a survival rate of 3% and 25% of the variability explained by the control variables, including more than 4580 patients would allow to detect an absolute difference of 4% in survival between both groups with a power of more than 90%. Results: A total of 4893 patients (2869 men and 2024 women) with a mean age of 70 years (standard deviation 17) were included, of whom 450 (9.2%) experienced a conversion to a shockable rhythm during the course of their prehospital resuscitation. Among all patients, 146 patients (3.0%) survived to discharge and 633 (12.9%) experienced prehospital ROSC. In the univariate models, there was no association between the conversion to a shockable rhythm and survival (odds ratio [OR] 1.14 [95% confidence interval {CI} 0.66-1.95]), but a significant assocation was observed with ROSC (OR 2.00 [95% CI 1.57-2.55], p<0.001). However, there was no independent association between the conversion to a shockable rhythm and survival (adjusted OR [AOR] 0.92 [95% CI 0.51-1.66], p=0.78) and prehospital ROSC (AOR 1.30 [95% CI 0.98-1.72], p=0.073). Conclusion: There is no clinically significant association between the conversion to a shockable rhythm and resuscitation outcomes in patients suffering from OHCA. The initial rhythm remains a much better outcome predictor than subsequent rhythms and should be preferred when evaluating the eligibility for advanced resuscitation procedures.

Introduction: Introduction: Paramedics frequently make immediate life-altering decisions with minimal clinical information. This applies to their decision to treat an unconscious patient with naloxone when the history of an opioid overdose cannot be readily established. Among patients treated by paramedics with naloxone, our objective was to compare patient demographics, treatment interventions and clinical response between patients with and without a confirmed history of an opioid overdose. Methods: Methods: This was a retrospective cohort study design of consecutive patients treated with naloxone by paramedics between January 1, 2016, and June 30, 2017. Patients were classified based on whether paramedics did or did not document a history of an opioid overdose. Baseline characteristics, treatment interventions, and response to naloxone were compared between groups. Comparisons were done using a chi-squared or Fishers exact test. Results: Results: We identified 294 patients of whom 113 (38%) did not have a confirmed history of an opioid overdose. The groups were similar in gender, bystander CPR, and bystander administration of naloxone. There were no differences in the presence of pinpoint pupils, initial oxygen saturation, initial Glasgow Coma Score (GCS), respiratory rate, or time on scene. Both patient groups were managed similarly with respect to route of naloxone administration and the use of a bag valve mask. All patients who were intubated were in the no confirmed history group (n=5; p=.003). Post naloxone there were no differences in last recorded vital signs except the no confirmed history group was less likely to achieve a GCS 10 (57% versus 89%; p<.001). The overall post-naloxone development of agitation (9%) was moderate while the need for physical/chemical restraint (2%) was low with no differences between groups. All patients were transported to the hospital. Conclusion: Conclusion: A substantial proportion of patients who received naloxone did not have a confirmed history of an opioid overdose. These patients closely resembled those with a confirmed history with respect to demographics and physical characteristics. The primary difference was a lower proportion of patients with no confirmed history who achieved a post naloxone GCS 10. Despite a moderate development of post naloxone agitation, paramedics were able to manage most of these patients without the use of physical/chemical restraints.

Research into the gut microbiota of human infants is necessary in order to better understand how inter-species interactions and ecological succession shape the diversity of the gut microbiota, and in turn, how the specific composition of the gut microbiota impacts on host health both during infancy and in later years. Blastocystis is a ubiquitous intestinal protist that has been linked to a number of intestinal and extra-intestinal diseases. However, emerging data show that asymptomatic carriage is common and that Blastocystis is prevalent in the healthy adult gut microbiota. Nonetheless, little is known about the prevalence and diversity of this microorganism in the healthy infant gut, including when and how individuals become colonized by Blastocystis. Here, we surveyed the prevalence and diversity of Blastocystis in an infant population (n = 59) from an industrialized country (Ireland) using Blastocystis-specific primers at three or more time-points up to 24 months old. Only three infants were positive for Blastocystis (prevalence = 5%) and this was only noted for samples collected at month 24. This rate is comparatively low relative to previously reported prevalence rates in the contemporaneous adult population. These data suggest that infants in Westernized countries that are successfully colonized by Blastocystis most likely acquire this microorganism via horizontal transfer.

The mechanics of snow friction are central to competitive skiing, safe winter driving and efficient polar sleds. For nearly 80 years, prevailing theory has postulated that self-lubrication accounts for low kinetic friction on snow: dry-contact sliding warms snow grains to the melting point, and further sliding produces meltwater layers that lubricate the interface. We sought to verify that self-lubrication occurs at the grain scale and to quantify the evolution of real contact area to aid modeling. We used high-resolution (15 µm) infrared thermography to observe the warming of stationary snow under a rotating polyethylene slider. Surprisingly, we did not observe melting at contacting snow grains despite low friction values. In some cases, slider shear failed inter-granular bonds and produced widespread snow movement with no persistent contacts to melt (μ < 0.03). When the snow grains did not move and persistent contacts evolved, the slider abraded rather than melted the grains at low resistance (μ < 0.05). Optical microscopy revealed that the abraded particles deposited in air pockets between grains and thereby carried heat away from the interface, a process not included in current models. Overall, our results challenge whether self-lubrication is indeed the dominant mechanism underlying low snow kinetic friction.

Adding nitrate to or increasing the concentration of lipid in the diet are established strategies for reducing enteric methane (CH4) emissions, but their effectiveness when used in combination has been largely unexplored. This study investigated the effect of dietary nitrate and increased lipid included alone or together on CH4 emissions and performance traits of finishing beef cattle. The experiment was a 2×4 factorial design comprising two breeds (cross-bred Aberdeen Angus (AAx) and cross-bred Limousin (LIMx) steers) and four dietary treatments (each based on 550 g forage : 450 g concentrate/kg dry matter (DM)). The four dietary treatments were assigned according to a 2×2 factorial design where the control treatment contained rapeseed meal as the main protein source, which was replaced either with nitrate (21.5 g nitrate/kg DM); maize distillers dark grains (MDDG, which increased diet ether extract from 24 to 37 g/kg DM) or both nitrate and MDDG. Steers (n=20/dietary treatment) were allocated to each of the four treatments in equal numbers of each breed with feed offered ad libitum. After 28 days adaptation to dietary treatments, individual animal intake, performance and feed efficiency were recorded for 56 days. Thereafter, CH4 emissions were measured over 13 weeks (six steers/week). Increasing dietary lipid did not adversely affect animal performance and showed no interactions with dietary nitrate. In contrast, addition of nitrate to diets resulted in poorer live-weight gain (P<0.01) and increased feed conversion ratio (P<0.05) compared with diets not containing nitrate. Daily CH4 output was lower (P<0.001) on nitrate-containing diets but increasing dietary lipid resulted in only a non-significant reduction in CH4. There were no interactions associated with CH4 emissions between dietary nitrate and lipid. Cross-bred Aberdeen Angus steers achieved greater live-weight gains (P<0.01), but had greater DM intakes (P<0.001), greater fat depth (P<0.01) and poorer residual feed intakes (P<0.01) than LIMx steers. Cross-bred Aberdeen Angus steers had higher daily CH4 outputs (P<0.001) but emitted less CH4 per kilogram DM intake than LIMx steers (P<0.05). In conclusion, inclusion of nitrate reduced CH4 emissions in growing beef cattle although the efficacy of nitrate was less than in previous work. When increased dietary lipid and nitrate inclusion were combined there was no evidence of an interaction between treatments and therefore combining different nutritional treatments to mitigate CH4 emissions could be a useful means of achieving reductions in CH4 while minimising any adverse effects.