Trends in Antimicrobial Usage on Swiss Pig Farms from 2018 to 2021: Based on an Electronic Treatment Journal.

(1) Background: The aim of this retrospective observational study was to observe the trends in antimicrobial usage (AMU) from 2018 to 2021 in Swiss pigs based on an electronic treatment journal used nationwide by farmers. Thus, for the first time, standardized, longitudinal comparisons of AMU between the years could be analyzed, as well as the influence of targeted interventions, on farms with higher consumption. (2) Methods: The data was evaluated by different indicators, such as the amount of active ingredient in kilograms, treatment days per farm (ATI) and treatment incidence (TI) based either on animal-defined daily doses (TIADD) or used daily doses (TIUDD). Calculations were performed across the following five age categories: suckling piglets, weaners, fattening pigs, and gestating and lactating sows, and the proportions of antimicrobial classes were evaluated for each age category. (3) Results: The highest amount of the active ingredient was administered to the group of fattening pigs, while the suckling piglets received the lowest amount of the active ingredient. In 2021, there was a significant decrease in active ingredient consumption per pig, but a significant increase in ATI, TIADD and TIUDD compared to 2018. The largest proportion of AMU was attributed to penicillins each year, followed by sulfonamides and tetracyclines. The "Highest Priority Critically Important Antimicrobials" represented a proportion of overall usage, declining from 5.2% in 2018 to 3.1% in 2021, while polypeptides were the most used class of critical antimicrobials. Interventions on high-usage farms showed that some farms decreased their AMU in the following year while others did not. (4) Conclusions: This study reveals a decrease in the overall usage measured in kilograms per pig of antimicrobials in Swiss pigs between 2019 and 2021 through the monitoring of AMU, but, at the same time, there was an increase in treatment days or incidence per farm. Critical antimicrobials can be reduced regardless of the indicator. The significance and quality of interventions should be investigated in future studies.

Comparison of Antibiotic Use and the Frequency of Diseases Depending on the Size of Herd and the Type of Cattle Breeding.

Diseases are responsible for losses in livestock production by increasing animal mortality and reducing productivity. The administration of antibiotics can help mitigate these negative effects. However, inappropriate use can lead to severe complications, such as raising antibiotic resistance. The purpose of this study was to perform a comparative analysis of antibiotic use and disease frequency over four years, based on the size of dairy farms and the type of farm. The study covered a 4-year period and included medium dairy farms (20-50 cows, n = 13), large dairy farms (>250 cows, n = 8), and large beef farms (n = 8). The collected data involved antimicrobial use but also included farm demographics, animal health, disease frequency, and herd management practices. The criteria used to categorise antibiotics into groups A-D were based on the EMA guidelines. The carried-out study showed that the large dairy cattle farms had the highest antibiotic consumption (18.29 mg·PCU-1), due to the high frequency of diseases, and consequently, the treatment of calf (diarrhoea, lung inflammations) and cow diseases (general treatment and mastitis). Cattle on large beef farms suffer mainly from general diseases caused by maintenance and herd management conditions. The use of restrict antibiotics was, in some cases, unjustified (antibiotics for dry cow therapy). Future studies should consider a larger number of farms, taking into account the given direction of cattle production.

Effect of a dairy farmworker stewardship training program on antimicrobial drug usage in dairy cows.

Antimicrobial use (AMU) is critical to preserving animal health and welfare. However, the development of antimicrobial resistance (AMR) represents a public health threat. Although most antimicrobials used on the farm require a veterinarian prescription, farmworkers make daily on-farm treatment decisions. Therefore, farmworker training is vital to promote responsible AMU. This research project aimed to evaluate the effect of farmworker antimicrobial stewardship (AMS) training on the quantity of AMU on dairy farms in Ohio and California. We hypothesized that farms receiving AMS training would have reduced AMU in dairy cattle compared with farms where training wasn't administered. We designed a quasiexperimental study with 18 conventional dairy farms enrolled in Ohio and California. Twelve farms received AMS training, and 6 farms did not. The AMS program included a 12-wk training focused on accurate identification of cows requiring antimicrobial treatment. We quantified AMU by collecting used drug containers, manually counted by researchers during farm visits. Treatment incidence (TI) was calculated using animal daily doses (ADD), and Poisson regression models were used to analyze the TI data. Disease incidence rate (DIR) in lactating cows was 2.2, 1.5, 1.0, 0.4, 0.3, 0.2, and 0.03/1,000 cow-days for mastitis, lameness, metritis, pneumonia, retained placenta, diarrheas, and other diseases (e.g., conjunctivitis, injuries), respectively. The highest TI by antimicrobial class (provided in ADD/1,000 cow-days) was cephalosporin (5.9), penicillin (5.2), tetracyclines (0.4), lincosamides (0.2), and sulfonamides (0.1). Among the trained farms using a within-treatment group analysis, no significant differences were observed in TI pre-intervention (10.9 ADD/1,000 cow-days) compared with TI postintervention (10.3 ADD/1,000 cow-days). Treatment incidence from the training group was 10.8 ADD/1,000 cow-days and although numerically lower, it was not significantly different compared with TI in the control groups at 13.9 ADD/1,000 cow-days (rate ratio = 0.77, CI = 0.25-2.38). Future research on AMS should incorporate farmworker training with social science approaches to overcome barriers and promote on-farm responsible use.

Quantitative and qualitative analysis of antimicrobial usage and biosecurity on broiler and Sonali farms in Bangladesh.

Antimicrobial use (AMU) is a major contributing factor to the rising threat of antimicrobial resistance (AMR) in human and animals. To control AMR, indiscriminate antibiotic use needs to be restricted, preventive measures such as biosecurity must be prioritized and proper action plans must be implemented. This study aimed to quantify and associate AMU and biosecurity status of broiler and Sonali farms in Bangladesh. Data on all antimicrobial treatments administered during a batch production cycle and antimicrobials purchased over a year were collected from 94 conventional broiler and 51 Sonali (cross-breed) farms from the northern and southeast regions of Bangladesh. Flock-level AMU was quantified using Treatment Incidence (TI) per 100 days based on the Defined Daily Dose (TIDDDvet) expressing the number of days per 100 animal-days at risk that the flock receives a standard dose of antimicrobials. The biosecurity status (external and internal) of these farms was assessed by means of the Biocheck.UGent scoring system and the correlation between biosecurity and TIDDDvet were assessed by Pearson's correlation coefficients. Median flock TIDDDvet was 60 and 58 for broilers and Sonali flocks, indicating that the birds were treated around 60% and 58% of their lifetime with an antimicrobial dose, respectively. Minimum and maximum values of TIDDDvet ranged from 18 -188 and 31-212 in broilers and Sonali, respectively. Fluoroquinolones, sulfonamides, tetracyclines and aminopenicillins were the most frequently used antimicrobial classes. The mean external and internal biosecurity scores were 39% and 61% for broilers and 44% and 61% for Sonali, respectively. There was a statistically significant difference in the external biosecurity score in broiler farms in the two regions (p ≤ 0.001), whereas, the internal biosecurity score was borderline not statistically significantly different (p = 0.065). The biosecurity score was negatively correlated with AMU in broiler and sonali farms both for external (R2 =-0.38; -0.36) and internal biosecurity (R2 =-0.33; -0.32), respectively. As most of the farmers treated their birds with antimicrobials for a very large part of the production, it could be concluded that there is a high overuse of antimicrobials both in broiler and Sonali poultry production in Bangladesh. This study also highlighted a low level of farm biosecurity practices. Overuse of antimicrobials and low level of biosecurity practice may be due to a lack of knowledge, ignorance, avoid loss and/or lack of monitoring by governmental agencies. Therefore, urgent action is required to increase awareness and biosecurity levels and to reduce AMU in these production systems.

Antimicrobial use and its association with the presence of methicillin-resistant staphylococci (MRS) and extended-spectrum beta-lactamases (ESBL)-producing coliforms in mastitic milk on dairy farms in the Chiba Prefecture, Japan.

Food-producing animals, including dairy cattle, are potential reservoirs of antimicrobial resistance. However, there is limited data on antimicrobial use and the selection of resistant bacteria. Therefore, we investigated the association between antimicrobial use and resistance to mastitis pathogens using 2016 data from milk samples collected from cows with mastitis in 134 dairy farms in Chiba Prefecture, one of the principal dairy production prefectures in Japan. We recorded the antimicrobial use and isolation of methicillin-resistant staphylococci (MRS) and extended-spectrum beta-lactamase (ESBL)-producing coliforms (E. coli and Klebsiella spp.), and used the antimicrobial treatment incidence (ATI; the theoretical number of animals per 1000 animal-days subjected to antimicrobial treatment) to indicate antimicrobial use on each farm. The farms in which MRS or ESBL-producing coliforms were isolated from at least one mastitic milk sample were classified as antimicrobial resistance (AMR)-positive, and those in which neither MRS nor ESBL-producing coliforms were isolated were classified as AMR-negative. The AMR-positive farms showed a significantly higher ATI (median 45.17) than AMR-negative farms (median 38.40). The results indicate that high antimicrobial usage is associated with AMR in staphylococci and coliforms isolated from mastitic milk on dairy farms in Chiba Prefecture.

Evaluating the antimicrobial use on dairy farms in Chiba Prefecture in Japan using the antimicrobial treatment incidence, an indicator based on Japanese defined daily doses from 2014-2016.

The use of antimicrobial agents in food-producing animals may lead to the emergence and spread of antimicrobial resistance in bacteria of animal origin. However, there is a paucity of data on the quantity of antimicrobials use on dairy farms in Japan. This study describes antimicrobial use on dairy farms from 1 January 2014 to 31 December 2016 in five administrative districts (central, eastern, western, southern and northern) of Chiba Prefecture. The use of antimicrobial agents in dairy cattle over these three years was evaluated in terms of the antimicrobial treatment incidence (ATI; theoretical number of animals per 1,000 animal-days subjected to antimicrobial treatment) using data collected from a total of 442 dairy farms in that prefecture. Our results revealed that the average ATI on these farms for these years ranged from 38.7 to 39.4 with no significant difference between years and that the average ATI for these administrative districts varied between 32.9 and 43.2 with a significant variation between some of the districts. Approximately 84% of antimicrobials were administered intramammarily, 13-14% by injection and 1-2% orally. Scenario analyses were performed to assess the effect of changes in some of the defined daily dose (DDDjp) values used to calculate the ATI. Our results revealed that the calculated ATI is considerably affected by the changes in the long-acting factor used for assigning the DDDjp values of intramammary products for dry cows and the way in which DDD values are assigned for combination products.

[Intramammary use of antibiotics in dairy farms in the canton of Ticino before, during and after Staphylococcus aureus genotype B elimination]. / Intramammärer Antibiotikaeinsatz vor, während und nach einer Staphylococcus aureus Genotyp B Sanierung in Milchkuhbetrieben im Kanton Tessin.

INTRODUCTION: The aim of the study was to evaluate the use of intramammary antibiotics before, during and after the elimination of Staphylococcus aureus genotype B (SAGTB). Data on intramammary antibiotic use was collected in 65 dairy farms as part of a pilot project for SAGTB elimination in the canton of Ticino from 2017 to 2019. The investigated farms were divided into 46 affected farms (with at least one SAGTB-positive animal) and 19 control farms (SAGTB-free farms). Data on antibiotic use were requested from veterinarians and treatment incidence, as a measure of antibiotic use, was calculated based on medical records and veterinary prescriptions. In addition, the treatment incidence was calculated for 47 farms during alpine farming period. In 2018 (elimination year), the mean incidence of treatment during lactation in the SAGTB-positive farms was significantly higher than in the control farms (p=0,003). In 2019 no significantly lower antibiotic use during lactation or dry period was detected between 2017 (before elimination) and 2019 (after elimination). Alpine farming places where only S. aureus genotype B-negative animals had access to had a significantly lower antibiotic use during lactation (p=0,004). The new federal database (Antibiotics Information System in Veterinary Medicine, IS ABV) should allow continuous monitoring and to confirm the reduction of antibiotic use in the coming years.

INTRODUCTION: L'objectif de l'étude était d'évaluer la consommation d'antibiotiques intramammaires avant, pendant et après l'assainissement de Staphylococcus aureus génotype B (SAGTB). Dans le cadre d'un projet pilote d'assainissement SAGTB dans le canton du Tessin, l'étude a recueilli des données sur la consommation d'antibiotiques intramammaires de 2017 à 2019 dans 65 exploitations laitières réparties en 46 exploitations test (avec au moins un animal positif au SAGTB) et 19 exploitations témoins (exploitations exemptes de SAGTB). Les données relatives à la consommation d'antibiotiques ont été demandées aux vétérinaires et, grâce aux enregistrements et aux prescriptions des vétérinaires, il a été possible de calculer l'incidence du traitement en tant que mesure de la consommation d'antibiotiques. En outre, l'incidence des traitements pendant l'alpage a également pu être calculée pour 47 exploitations. En 2018 (année d'assainissement), l'incidence des traitements pendant la lactation était en moyenne significativement plus élevée dans les exploitations SAGTB-positives que pour les exploitations de contrôle (p=0,003). En comparant 2017 (avant l'assainissement) et 2019 (après l'assainissement), il n'y a pas eu de baisse significative de la consommation d'antibiotiques pendant la lactation et le tarissement en 2019. Dans les exploitations d'estivage, on a constaté l'année suivant l'assainissement (2019) une consommation d'antibiotiques significativement plus faible pendant la lactation pour les alpages qui n'accueillaient que des animaux négatifs à S. aureus génotype B (p=0,004). Il faut espérer qu'avec l'aide de la nouvelle base de données fédérale (Système d'information sur les antibiotiques en médecine vétérinaire, IS ABV), le monitoring pourra être poursuivi dans les années à venir et que la réduction de la consommation d'antibiotiques sera confirmée dans les années suivantes.

The use of common antimicrobial agents in US veal calves.

The use of antimicrobials in food animals and the selection of antimicrobial-resistant pathogens continue to be prominent concerns for human food safety and public health. To provide optimal stewardship programs, antimicrobial use in animal production operations must be quantified and standardized for benchmarking and creating goals, monitoring temporal trends, and identifying causes of emerging resistance. In the United States, quantified estimates of antimicrobial use are available in dairy and beef cattle, but these data have not been generated for veal calf herds. Therefore, the objective of this study was to estimate the treatment incidence (TI) of antimicrobials for eight US veal calf farms in one rearing cycle. Treatment incidences were compared between calculated doses defined by the labeled daily dose (LDD), animal-defined daily dose (ADD) from the European Medicines Agency (EMA) guideline, and the used daily dose (UDD) from the farm treatment protocols. Among eight farms, veal calves received a mean of 34.40 LDD, 34.88 ADD, and 28.68 UDD of an antimicrobial per 100 days. The lower TI based on the UDD administration was a result of higher farm protocol dosing relative to the labeled and EMA daily doses. Higher quantities of antimicrobial administration were observed in the first three weeks (day 1-21) of rearing (Tukey-adjusted p < .05). This study is the first to quantitatively estimate the TI of antimicrobials on the US veal calf operations and serves as an important step toward the development of antimicrobial stewardship programs.

Promoting Judicious Antimicrobial Use in Beef Production: The Role of Quarantine.

Judicious antimicrobial stewardship in livestock industry is needed to reduce the use of antimicrobials (AMU) and the associated risk of antimicrobial resistance. Biosecurity measures are acknowledged for their role against the spread of diseases and the importance in reducing AMU in different species. However, their effectiveness in beef production has been scarcely considered. The aim of this study was to investigate the effect of the quarantine strategy on AMU in beef cattle. A total of 1206 Charolaise animals in five farms were included in the trial. Roughly half of the animals followed the standard procedure of the fattening cycle (no-quarantine; NO-QUA group) and half followed a 30-day period of quarantine (QUA group) since their arrival. Performance and antimicrobial data were recorded and a treatment incidence 100 (TI100it) per animal was calculated. Penicillins was the most used class of antimicrobials. Differences between groups were significant for males only, with NO-QUA group having greater TI100it (3.76 vs. 3.24; p < 0.05) and lower body weight at slaughter (713.4 vs. 723.7 kg; p < 0.05) than QUA group. Results suggest that quarantine strategy can reduce AMU in males without compromising their performance, whereas further investigation is needed for females.

Assigning Defined Daily/Course Doses for Antimicrobials in Turkeys to Enable a Cross-Country Quantification and Comparison of Antimicrobial Use.

Antimicrobial resistance (AMR) threatens our public health and is mainly driven by antimicrobial usage (AMU). For this reason the World Health Organization calls for detailed monitoring of AMU over all animal sectors involved. Therefore, we aimed to quantify AMU on turkey farms. First, turkey-specific Defined Daily Dose (DDDturkey) was determined. These were compared to the broiler alternative from the European Surveillance of Veterinary Antimicrobial Consumption (DDDvet), that mention DDDvet as a proxy for other poultry species. DDDturkey ranged from being 81.5% smaller to 48.5% larger compared to its DDDvet alternative for broilers. Second, antimicrobial treatments were registered on 60 turkey farms divided over France, Germany and Spain between 2014 and 2016 (20 flocks per country). Afterwards, AMU was quantified using treatment incidence (TI) per 100 days. TI expresses the percentage of the rearing period that the turkeys were treated with a standard dose of antimicrobials. Minimum, median and maximum TI at flock level and based on DDDturkey = 0.0, 10.0 and 65.7, respectively. Yet, a huge variation in amounts of antimicrobials used at flock level was observed, both within and between countries. Seven farms (12%) did not use any antimicrobials. Aminopenicillins, polymyxins, and fluoroquinolones were responsible for 72.2% of total AMU. The proportion of treating farms peaked on week five of the production cycle (41.7%), and 79.4% of the total AMU was administered in the first half of production. To conclude, not all DDDvet values for broilers can be applied to turkeys. Additionally, the results of AMU show potential for reducing and improving AMU on turkey farms, especially concerning the usage of critically important antimicrobials.

Antimicrobial use in poultry flocks in Austria between 2013 and 2019.

BACKGROUND: The increase in bacteria that are resistant to antimicrobials-often selected for a high level of antimicrobial uses (AMUs) in human beings or food-producing animals-is a global concern. The Austrian Poultry Health Service (QGV) has established a database containing comprehensive information on poultry flocks in Austria. METHODS: AMU in 32,411 broiler flocks and 2946 turkey flocks between 2013 and 2019 is analysed by calculating different metrics, including the treatment incidence TI1000 . Furthermore, the Austrian benchmarking system for poultry is introduced. RESULTS: Annual AMU in broilers decreased from 1030.8 kg of active ingredient to 762.5 kg between 2013 and 2016 but rose again to 1165.0 kg in 2019; while for turkeys annual AMU dropped from 1196.4 kg to 569.0 kg between 2013 and 2019. At the same time, the proportion of treated flocks decreased from 34.2% to 24.8% for broilers and from 54.3% to 44.0% for turkeys. In both broilers and turkeys, the most frequently used antimicrobial class, according to the TI1000 unit, in broilers and turkeys is polymyxins. CONCLUSION: Calculating different metrics enables a deeper insight into AMU. Total AMU reduced without legislation but the increase of AMU in broiler production needs further investigation.

Antibiotic and medical zinc oxide usage in Danish conventional and welfare-label pig herds in 2016-2018.

This register-based study compared the usage of antibiotics and medical zinc oxide (ZnOmed) in three different pig production systems: organic, conventional free-range and conventional indoor in 2016-2018. ZnOmed is used to prevent weaning diarrhoea with a dosage of max 2500 mg zinc/kg feed for 14 days post weaning. The treatment incidence (TI) of antibiotics (injectable and oral) and ZnOmed was calculated as the total number of animal daily doses (ADD) per 100 animals per day at herd level over a calendar year. Zero-inflated negative binomial models were used to compare the antibiotic and ZnOmed usage across the three production systems. The correlation between antibiotic and ZnOmed usage was evaluated using Spearman's correlation coefficient. In all age groups, the antibiotic TI was highest in the conventional indoor system, lower in the conventional free-range system and lowest in the organic system. In weaners, which is the age group with the highest antibiotic usage, conventional indoor, conventional free-range and organic herds had an average TI of 7.20, 3.37 and 0,48 ADD/100 animals/day, respectively. Another important finding in the study was that non-use of antibiotics is more common (>30% of herds) in welfare-label production systems (organic and conventional free-range) than in conventional indoor production (16% of herds). The overall differences in usage of ZnOmed between the three production systems were not statistically significant, but the probability of not using ZnOmed, was significantly higher for organic (36%) and conventional free-range herds (61%) compared to conventional indoor herds (19%). There was a weak to moderate positive correlation between antibiotic and ZnOmed usage at herd level with the weakest correlation in conventional indoor herds (0.31). The results indicate that ZnOmed does not appear to replace or prevent the use of antibiotics and suggest that ZnOmed is used differently in different systems. A weak correlation between the usage of antibiotics and ZnOmed in conventional indoor herds could reflect a frequent use of routine treatments within this system. The lower level of antibiotic usage in welfare-label systems indicates that a significant reduction in antibiotic use in pig production would require housing and management changes or regulatory changes in the conventional indoor system. The large variation in both antibiotic and ZnOmed usage between herds in similar production systems indicates that a further reduction in use of antibiotics and ZnOmed is achievable.

Exploring potential risk factors of antimicrobial use in beef cattle.

Livestock species are major contributors to the increase of antimicrobial (AM) resistance which is a worldwide concern for both human and animal health. The over-use of AM is widely acknowledged, however, unlike pigs, poultry and dairy cattle, knowledge on potential risk factors affecting AM usage (AMU) in beef industry is limited. Hence, this study aimed to investigate the impact of farm, breed, sex and season of arrival of purchased beef cattle on AMU in Italian beef cattle. Data on 1063 batches were collected from January 2016 to April 2019 from specialised beef fattening farms located in the north of Italy. Information on breed, sex, date of arrival, performance traits and AM agents used on farm was collected, and the treatment incidence 100 (TI100) indexes per batch were calculated using the defined daily dose animal estimated according to Italian summaries of product characteristics. Factors affecting TI100 indexes were investigated using a cross-classified multilevel model. Farms largely differed in terms of AMU. Males had greater AMU than females (P < 0.001), likely due to their higher susceptibility to disease. Statistically significant differences were observed between seasons of arrival with summer and spring having lower TI100 indexes than winter and autumn (P < 0.001). Indeed, winter is commonly linked to an increase in respiratory diseases in beef cattle. Finally, the TI100it indexes tended to be different among breeds with Blonde d'Aquitaine and Limousine having greater AMU compared to the other breeds. Results of this study provided valuable information on potential risk factors of AMU in beef production which may be useful to address its reduction. For instance, the development of tailored management strategies for specific breeds, targeted approaches to improve the health of males as well as greater care towards batches purchased in winter are possible advice to implement on-farm for a more responsible AM stewardship.

Welfare Assessment in Calves Fattened According to the "Outdoor Veal Calf" Concept and in Conventional Veal Fattening Operations in Switzerland.

The "outdoor veal calf" system was developed to encounter the demand for a veal fattening system that allows for reducing antimicrobial use without impairing animal welfare. Management improvements including direct purchase, short transportation, vaccination, three-week quarantine in individual hutches, and open-air housing in small groups in a roofed, straw-bedded paddock with a group hutch were implemented in a prospective intervention study (1905 calves, 19 intervention and 19 control farms, over one year): antimicrobial use was five times lower in "outdoor veal" farms compared to control farms (p < 0.001), but it was crucial to ensure that antimicrobial treatment reduction was not associated with decreased animal welfare, i.e., that sick animals were not left untreated. Welfare was assessed monthly on the farms, and organs of 339 calves were examined after slaughter. Cough and nasal discharge were observed significantly (p ≤ 0.05) less often in intervention than in control farms, mortality (3.1% vs. 6.3%, p = 0.020) and lung lesion prevalence (26% vs. 46%, p < 0.001) were lower; no group difference was seen in abomasal lesion prevalence (65% vs. 72%). Thus, besides reduced antimicrobial use, calf health and welfare were improved in "outdoor veal calf" farms in comparison to traditional operations.

What drives antimicrobial prescribing for companion animals? A mixed-methods study of UK veterinary clinics.

Antimicrobial use in companion animals is a largely overlooked contributor to the complex problem of antimicrobial resistance. Humans and companion animals share living spaces and some classes of antimicrobials, including those categorised as Highest Priority Critically Important Antimicrobials (HPCIAs). Veterinary guidelines recommend that these agents are not used as routine first line treatment and their frequent deployment could offer a surrogate measure of 'inappropriate' antimicrobial use. Anthropological methods provide a complementary means to understand how medicines use makes sense 'on-the-ground' and situated in the broader social context. This mixed-methods study sought to investigate antimicrobial use in companion animals whilst considering the organisational context in which increasing numbers of veterinarians work. Its aims were to i) to epidemiologically analyse the variation in the percentage of antimicrobial events comprising of HPCIAs in companion animal dogs attending UK clinics belonging to large veterinary groups and, ii) to analyse how the organisational structure of companion animal practice influences antimicrobial use, based on insight gained from anthropological fieldwork. A VetCompassTM dataset composed of 468,665 antimicrobial dispensing events in 240,998 dogs from June 2012 to June 2014 was analysed. A hierarchical model for HPCIA usage was built using a backwards elimination approach with clinic and dog identity numbers included as random effects, whilst veterinary group, age quartile, breed and clinic region were included as fixed effects. The largest odds ratio of an antimicrobial event comprising of a HPCIA by veterinary group was 7.34 (95% confidence interval 5.14 - 10.49), compared to the lowest group (p < 0.001). Intraclass correlation was more strongly clustered at dog (0.710, 95% confidence interval 0.701 - 0.719) than clinic level (0.089, 95% confidence interval 0.076 -0.104). This suggests that veterinarians working in the same clinic do not automatically share ways of working with antimicrobials. Fieldwork revealed how the structure of the companion animal veterinary sector was more fluid than that depicted in the statistical model, and identified opportunities and challenges regarding altering antimicrobial use. These findings were organised into the following themes: "Highest priority what?"; "He's just not himself"; "Oh no - here comes the antibiotics police"; "We're like ships that pass in the night"; and "There's not enough hours in the day". This rigorous mixed-methods study demonstrates the importance of working across disciplinary silos when tackling the complex problem of antimicrobial resistance. The findings can help inform the design of sustainable stewardship schemes for the companion animal veterinary sector.

Use of antimicrobials in beef cattle: an observational study in the north of Italy.

Antimicrobial resistance is a worldwide issue whereby a more prudent use of medications is needed, especially for those antimicrobials (AM) classified as 'highest priority critically important antimicrobials' (HPCIAs) which are likely contributors to the development of resistance. So far, data on antimicrobial use (AMU) in EU are mainly reported at sales level while information on real use, mostly in beef production, is poor. The most reliable indicator to measure AMU is the treatment incidence (TI100) calculated by using the Defined Daily Dose Animal (DDDA) as stated by the European Medicines Agency (EMA). Although Italy ranks second among EU countries with regard to the AM sales in livestock production, data on AMU of the Italian beef production is still lacking, whereby the aim of this study was to provide information on the current scenario of AMU in Italian beef cattle. Data were collected from January 2016 to April 2019 from specialized beef fattening farms located in the north of Italy yielding a final dataset of 1376 batches. Data on performance and AM agents used in the study were collected and TI100 indexes per batch were calculated according to both Italian and EMA's DDDA. A Kruskal-Wallis test was used to check for differences between years and seasons. Results showed a significant variation between years and seasons with a reduction of TI100 based on Italian DDDA as time progressed (P < 0.05). However, about 40% of the total amount of treatments administered were HPCIAs with macrolides accounting for the 27.7% of the total amount. The most common reasons of administration of AM were respiratory diseases (68.9%) and lameness (17.6%). Penicillins was the class of AM used on the highest proportion of batches (84.4%) showing that broad-spectrum AM were widely exploited among herds. In summary, despite a general reduction of AMU in beef cattle over time, a great use of HPCIAs was still observed suggesting that AM stewardship for Italian beef production should pay particular emphasis on the reduction of HPCIAs use. This shows how overall knowledge on where efforts need to be optimized is important to develop targeted strategies for a more responsible AM stewardship. Results of the current study may also contribute to define national and EU benchmark criteria for AMU, as a comparison with studies carried out in other countries or on other food-producing sectors is still challenging to achieve.

Effectiveness of alternative measures to reduce antimicrobial usage in pig production in four European countries.

BACKGROUND: The reduction of antimicrobial usage (AMU) is in the focus in modern pig production. The objective of this study was to assess the effectiveness of alternatives to reduce AMU at herd level. In a prospective study, 68 farrow-to-finish pig herds located in Belgium, France, Germany and Sweden were recruited on a voluntary basis to implement tailor-made intervention plans to reduce their AMU. Alternative measures included improvement of biosecurity (n = 29 herds), vaccination (n = 30), changes of feeding schemes or drinking water quality (n = 45), improved pig health and welfare care (n = 21) as well as changes in stable climate and zootechnical measures (n = 14). Herds were followed for 1 year after implementation of measures. Annual antimicrobial expenditures or treatment records, as well as disease incidence scores were collected and compared to those of the year before intervention. AMU was measured as the treatment incidence and calculated by age category, antimicrobial class and administration route. RESULTS: Compliance with the intervention plans was high (median 93%). AMU was significantly reduced following the implementation of alternative measures: in the median herd of the four countries, pigs were treated before intervention 25% of their expected lifespan (200 days from birth to slaughter) and after intervention 16%. AMU of suckling and weaned pigs were significantly reduced by 37 and 54%, respectively. The usage of polymyxins and tetracyclines was significantly reduced by 69 and 49%, respectively. AMU via feed and water, as well as parenteral AMU were significantly reduced by 46 and 36%, respectively. Herds with a higher AMU level before intervention achieved a bigger reduction. The majority of disease incidence were similar before and after intervention, with a few exceptions of disorders related to the gastro-intestinal tract in suckling pigs (decreased) and in breeding pigs (increased). CONCLUSION: Following tailor-made implementation of alternative measures, a substantial reduction of AMU in pig production was achievable without jeopardizing animal health. The AMU reduction in the youngest age categories (suckling and weaned pigs) and the reduction of group treatments via feed and water was in line with the recent European Guidelines on the prudent use of antimicrobials in veterinary medicine.

Effects of the novel concept 'outdoor veal calf' on antimicrobial use, mortality and weight gain in Switzerland.

The aim of the intervention study 'outdoor veal calf' was to evaluate a novel concept for calf fattening which aimed at reducing antimicrobial use without compromising animal health. Management practices such as commingling of calves from multiple birth farms, crowding, and suboptimal barn climate are responsible for high antimicrobial use and mortality in the veal calf population. The risk of selecting bacteria resistant to antimicrobials and of economic losses is accordingly elevated. The 'outdoor veal calf' concept, implemented in nineteen intervention farms (IF), is based on three main measures: 1. purchased calves are transported directly from neighboring birth farms to the fattening facility instead of commingling calves in livestock dealer trucks; 2. each calf is vaccinated against pneumonia after arrival and completes a three-week quarantine in an individual hutch; and 3. the calves spend the rest of the fattening period in outdoor hutches in groups not exceeding 10 calves. The covered and bedded paddock and the group hutches provide shelter from cold weather and direct sunshine, constant access to fresh air is warranted. Nineteen conventional calf fattening operations of similar size served as controls (CF). Every farm was visited once a month for a one-year period, and data regarding animal health, treatments, and production parameters were collected. Treatment intensity was assessed by use of the defined daily dose method (TIDDD in days per animal year), and calf mortality and daily weight gain were recorded in both farm groups. Mean TIDDD was 5.3-fold lower in IF compared to CF (5.9 ±â€¯6.5 vs. 31.5 ±â€¯27.4 days per animal year; p < 0.001). Mortality was 2.1-fold lower in IF than in CF (3.1% ± 2.3 vs. 6.3 % ± 4.9; p = 0.020). Average daily gain did not differ between groups (1.29 ±â€¯0.17 kg/day in IF vs. 1.35 ±â€¯0.16 kg/day in CF; p = 0.244). A drastic reduction in antimicrobial use and mortality was achieved in the novel 'outdoor veal calf' system without compromising animal health. The principles of risk reduction used in designing the system can be used to improve management and animal health, decrease the need for antimicrobial treatments and thus selection pressure on bacteria in veal operations.

How Input Parameters and Calculation Rules Influence On-Farm Antimicrobial Use Indicators in Animals.

A variety of indicators of antimicrobial use are available in veterinary medicine, their choice should depend on the study objective as none has been recognized as the most appropriate metric. Calculation of indicators of antimicrobial use is based on a number of parameters (e.g., treatment dose or weight at treatment) that can be informed using theoretical (also called "standard") or actual (also called "used") values. Although few studies compare the application of several indicators to the same antimicrobial data, the obtained results lead to apparent discrepancies or contradictions. This study aimed to investigate antimicrobial use at the weaning stage in French pig farms and, more specifically, the impact the sources of information regarding doses, body weight at treatment and treatment length, had on the indicators results. A cross-sectional survey was conducted, and data collected from 70 farms made it possible to calculate four indicators at the weaning stage using different input values. The indicator values did not show significant differences when calculated based on the theoretical dose and length of treatment (as recommended by the summary of product characteristics) or when calculated based on the dose used and treatment length as applied by the farmer. However, all of the indicators showed significant differences when calculated using the standard theoretical weight (15 kg) or actual weight (P < 0.05). It appears that if data collection plans cannot be harmonized, clarification of indicator calculations in the literature is needed to allow comparisons between studies.

Do Dairy Farming Systems Differ in Antimicrobial Use?

The quantitative assessment of antimicrobial use (AMU) in food-producing animals contributes to the provision of essential information for developing relevant and effective policies to reduce use and to control antimicrobial resistance. Information on AMU is available mainly for intensive dairy farming systems and specialized high-yielding breeds. The aim of this study is to investigate AMU in different dairy farming systems by comparing the treatment incidence in mountain farms with specialized high-yield dairy breeds or with dual-purpose breeds raised for milk production to the treatment incidence in lowland farms with specialized high-yield dairy breeds or with dual-purpose breeds raised for milk production. Significant differences were found only between the overall treatment incidence, as well as the treatment incidence of highest-priority critically important antimicrobials for human medicine, in lowland farms with high-yielding breeds and mountain farms with dual-purpose breeds. Mountain farms have a generally lower milk production and smaller herd size than lowland farms, provide cows with access to pasture, and limit concentrates in the diet. These management practices and the use of local/dual-purpose breeds could reduce the risk of production diseases and the consequent need for AMU.