Conventional and unsupervised artificial intelligence analyses identified risk factors for antimicrobial resistance on dairy farms in the province of Québec, Canada.

Antimicrobial resistance (AMR) is one of the greatest threats to global health worldwide and is threatening not only humans, but also animal production systems, including dairy farms. The objective of this paper was to describe risks factors associated with AMR on dairy farms in Québec, Canada. This observational cross-sectional study included 101 commercial dairy farms and took place between the springs of 2017 and 2018 for a one-year period. We explored risk factors such as farm practices and producer's knowledge (measured using a questionnaire), antimicrobial use (quantified using veterinary invoices), and the presence of Salmonella Dublin (tested by serology). We evaluated AMR with fecal Escherichia coli retrieved from pre-weaned calves and lactating cows using the following outcomes: the presence of extended-spectrum-ß-lactamase/AmpC resistance and the number of resistances to antimicrobial classes. We used logistic regression models to evaluate the association between each risk factor and the 2 outcomes for the 2 types of samples (pre-weaned calves and lactating cows). Furthermore, we explored the relationships between these risk factors utilizing data dimensionality reduction and hierarchical clustering. Outputs of these analyses were used as regressors for AMR in regression models. While the results for univariate analyses were ambiguous, the unsupervised analysis naturally categorized the sample of farms according to their health/treatment status (dimension 1, explaining 12.9% of the variance) and herd size (dimension 2, explaining 7.8%). Three clusters of farms were identified (cluster 1: mainly healthy herds and low ceftiofur users, cluster 2: relatively high ceftiofur users, cluster 3: farms with a higher incidence of diseases and higher antimicrobial treatment rates). Dimension 1 and cluster membership were statistically associated with the presence of extended-spectrum-ß-lactamase/AmpC resistance in lactating cows and in pre-weaned calves. Dimension 1 was also statistically associated with the number of resistances in lactating cows and in pre-weaned calves. This study highlights the complexity of analyzing risk factors associated with AMR. Our results suggest that the herd health status and the AMU-related practices used are associated with AMR in dairy farms. However, prospective studies are needed to confirm a causal relation.

Redefining on-farm practices: The perceived effect of a responsible antimicrobial use regulation on dairy farmers.

The global food animal industry faces a growing concern regarding antimicrobial resistance (AMR), primarily driven by the use of antimicrobials (AM) for the treatment, control, and prevention of diseases. Addressing this challenge requires promoting responsible antimicrobial use (AMU) practices. In 2019, the province of Québec, Canada, took a significant step by implementing a regulation that limits the use of AM of very high importance for human medicine (category I AM as defined by Health Canada) in the food animal industry. However, the implementation of such regulation can significantly influence behavioral shifts among producers, contributing to the wider effort against AMR. Therefore, the objective of this observational study was to describe the perceived changes in dairy producers' knowledge and on-farm practices following the implementation of this regulation, using a cohort design. Data collection involved administering questionnaires to 87 dairy producers from 3 regions of the province of Québec (Estrie, Montérégie, Centre-Du-Québec) before (2017-2018) and after (2020-2021) the implementation of the regulation. The questionnaires explored the descriptive characteristics of farms, the knowledge of producers about the categorization of AM, the on-farm treatment practices, and the perceived effects of the regulation. Statistical analysis included t-tests and McNemar tests to compare the paired data obtained using the 2 questionnaires. The results indicated an increase in the knowledge score (the number of AM correctly categorized by the producers by their importance for human medicine) after the implementation of the regulation, suggesting an improved understanding of the categorization of AM based on their importance for human medicine. Trends in AMU practices for treating clinical mastitis and reproductive diseases suggested that category I AM were less likely to be reported as the primary treatment after the regulation, whereas category II AM were more often reported as primary treatment. Adoption of the selective dry cow therapy method significantly increased, whereas the use of teat sealants remained unchanged. Moreover, producers had divergent perceptions regarding the effect of the regulation on the cure rates and disease frequencies. This disparity emphasizes the need for comprehensive data collection to discern the risks associated with such regulatory shifts. The study acknowledges several limitations, including the potential for recall bias, confirmation bias, and desirability bias. Despite these limitations, this study shows that implementing regulations to encourage responsible AMU drives positive transformations in producers' knowledge and on-farm practices. This underscores the pivotal effect of proactive interventions in combating the escalating threat of AMR within the global food animal industry.

Critique of Approaches for Evaluating Teaching and Proposal for a New Institutional Policy.

A review of current literature provides ample evidence that Student Evaluation of Teaching, as currently practiced, can be a biased and flawed evaluation of educator performance and student learning. Due to this, many institutions have developed their own internal multimodal approach for faculty evaluation and professional advancement review that removes the underlying bias associated with survey results. Ross University School of Veterinary Medicine created a taskforce to evaluate the current teaching assessment practices and provide an alternative method. Based on an extensive literature review, an institutional policy was created using a multimodal approach, combining student evaluations of teaching scores with peer review of teaching, review of teaching materials, mentorship, self-ratings, and self-reflection. The implementation plan for this policy is described to allow for a teaching evaluation process built on a philosophy of mentorship, guidance, and self-reflection; as well as the use of external professional exam metrics to review the institutional academic quality at large.

Descriptive study of a method for identification of the pylorus by ultrasound in lactating Holstein cows.

The purpose of this study was to develop a method for identification of the pylorus, in lactating Holstein cows, based on ultrasound examination and the use of external anatomical landmarks such as the mammary vein (anulus venae subcutaneae abdominis). An ultrasound method based on successive identification of 4 internal anatomical landmarks was developed. The procedure was performed 157 times, on clinically healthy lactating Holstein cows, with a portable ultrasound machine equipped with a 3.5 MHz curvilinear probe. The pylorus was identified with a success rate of 98.7% (155 times out of 157 procedures). The average position of the pylorus was noted near the entrance of the right mammary vein, with a craniocaudal and dorsoventral dispersion. This ultrasound method of identifying the pylorus is simple, effective, and rapid.

Étude descriptive d'une méthode échographique d'identification du pylore chez la vache Holstein en lactation. Le but de cette étude était de développer une méthode permettant d'identifier le pylore, basée sur un examen échographique et l'utilisation de repères anatomiques externes telle la veine mammaire (anulus venae subcutaneae abdominis). Une méthode échographique s'appuyant sur l'identification successive de quatre repères anatomiques internes a été développée. La procédure a été réalisée à 157 reprises avec un échographe portable muni d'une sonde sectorielle de 3,5 MHz sur des vaches Holstein saines en lactation. Le pylore a été identifié avec un taux de succès de 98,7 % (155 fois sur 157 procédures). La position moyenne du pylore a été notée à proximité de l'entrée de la veine mammaire droite, avec une dispersion cranio-caudale et dorso-ventrale. Cette méthode échographique d'identification du pylore est simple, efficace et rapide.(Traduit par les auteurs).

Cheek teeth apical infection in cattle: Diagnosis, surgical extraction, and prognosis.

OBJECTIVE: To report the clinical presentation, treatment, and outcome of cattle undergoing surgical extraction of apically infected cheek teeth (CT). STUDY DESIGN: Short case series. ANIMALS: Nine adult cattle. METHODS: Medical records were searched for cattle having a diagnosis of apical infection of CT that were treated with surgical extraction between 2005 and 2017. Data retrieved included clinical examination, ancillary tests, surgical procedure, and outcomes. RESULTS: The main presenting complaints were mandibular swelling and decreased appetite and milk production. In total, 7 mandibular and 3 maxillary CT were extracted, 7 molars and 3 premolars that were distributed more frequently on the left dental arcades (n = 7 CT). Two cattle had no visible external lesions. Radiograph images revealed that lucency surrounded all affected tooth roots. Mandibular teeth were removed by lateral buccotomy with removal of alveolar bone plate or retrograde repulsion, and maxillary teeth were removed by repulsion through a maxillary sinus flap. Most common bacterial isolates consisted of anaerobic bacteria (6/11 isolates) and Truperella pyogenes (3/11 isolates). The most common complications included inability to remove the tooth intact (n = 4 cattle) and surgical site infection (n = 5). All cattle remained in their herd after treatment. CONCLUSION: Surgical extraction of CT was achieved in all 9 cattle. The postoperative morbidity was high but without long-term consequences on animal productivity. CLINICAL SIGNIFICANCE: Surgical extraction of CT is a successful treatment for apical infection in cattle.

Arthroscopic approach and intra-articular anatomy of the dorsal and plantar synovial compartments of the bovine tarsocrural joint.

OBJECTIVE: To determine arthroscopic approaches to the dorsal and plantar synovial compartments of the tarsocrural joint in adult cattle, and to describe the arthroscopic intra-articular anatomy from each approach. STUDY DESIGN: Ex vivo study. ANIMALS: Fresh adult bovine cadavers (n = 7). METHODS: Two tarsocrural joint were injected with latex to determine arthroscopic portal locations and arthroscopy of the tarsocrural joint of 12 tarsi was performed. The dorsolateral approach was made through the large pouch located between the long digital extensor and peroneus longus tendons. The dorsomedial approach was made just medial to the common synovial sheath of the tibialis cranialis, peroneus tertius, and long digital extensor tendons. The plantarolateral and plantaromedial approaches were made lateral and medial to the tarsal tendon sheath, respectively. RESULTS: Each approach allowed visualization of the distal tibia articulating with the proximal trochlea of the talus. Consistently observed structures included the distal intermediate ridge of the tibia, and the medial and lateral trochlear ridges and trochlear groove of the talus. Lateral and medial malleoli were best assessed from dorsal approaches. From the lateral approaches evaluation of the abaxial surface of the lateral trochlear ridge allowed visualization of the fibulocalcaneal joint. From the plantar approaches additional observed structures included the coracoid process of the calcaneus, plantar trochlea of the talus, and plantar talotibial and talofibular ligaments. CONCLUSION: In cattle, the dorsolateral and plantarolateral approaches allowed for the best evaluation of the dorsal and plantar aspects of the tarsocrural joint, respectively.

Dorsal Arthroscopic Approach and Intra-Articular Anatomy of the Bovine Antebrachiocarpal and Middle Carpal Joints.

OBJECTIVE: To determine arthroscopic approaches to the dorsal synovial compartments of the antebrachiocarpal and middle carpal joints in adult cattle, and to describe the arthroscopic intra-articular anatomy from each approach. STUDY DESIGN: Ex vivo study. ANIMALS: Six fresh adult bovine cadavers. METHODS: Two carpi were injected with latex and dissected to determine the ideal location for arthroscopic portals. Arthroscopy of the antebrachiocarpal and middle carpal joints of 10 carpi was then performed. The dorsolateral approach was made between the extensor carpi radialis and common digital extensor tendons. The dorsomedial approach was made medial to the extensor carpi radialis tendon, midway between the distal radius and proximal row of carpal bones (antebrachiocarpal joint) and midway between the two rows of carpal bones (middle carpal joint), with the joint in flexion. RESULTS: Arthroscopy of the antebrachiocarpal joint allowed visualization of the distal radius, proximal aspect of the radial, intermediate and ulnar carpal bones, and a palmar ligament located between the radius and the intermediate carpal bone. The approach to the middle carpal joint allowed visualization of the distal aspect of the radial, intermediate, and ulnar carpal bones, the proximal aspect of the fourth and fused second and third carpal bones and an interosseous ligament. The most lateral articular structures (lateral glenoid cavity of the distal radius, ulnar carpal and fourth carpal bones) were difficult to assess. CONCLUSION: Dorsal approaches to the antebrachiocarpal and middle carpal joints allowed visualization of most intra-articular dorsal structures in adult cattle.

Surgical Correction of Traumatic Lateral Patellar Luxation.

OBJECTIVE: To report successful surgical repair of a grade IV lateral patellar luxation in a 437-kg heifer. STUDY DESIGN: Case report. ANIMAL: Seventeen-month-old Holstein heifer (437 kg). METHODS: Diagnosis of traumatic lateral patellar luxation was made based on physical examination, and confirmed on radiographs. Arthroscopic examination of the stifle assessed joint changes. Lateral patellar luxation was surgically repaired using lateral release of the patella and medial imbrication of the joint capsule. RESULTS: The heifer presented nonweight-bearing lameness of the left hind limb (5/5 lameness score). Unilateral grade IV lateral patellar luxation was diagnosed based on physical examination and radiography. Arthroscopic examination of the stifle showed synovitis and cartilage eburnation of the medial articular surface of the patella and of the lateral trochlear ridge of the femur. Lateral release of the patella and medial imbrication of the joint capsule was performed. The heifer remained lame (4.5/5 lameness score) and developed severe disuse muscle atrophy after surgery. By day 112, the heifer was walking easily and was completely weight bearing on the left hindlimb but did have a gait alteration (2/5 lameness score). On day 229, the heifer calved for the first time and lameness was no longer evident. CONCLUSION: This report documents successful surgical treatment of traumatic lateral patellar luxation in a large heifer but additional case evaluation is required to provide an accurate prognosis for this condition and treatment in large cattle.

Outcome Following Partial Unilateral Hysterectomy by Standing Flank Approach in Dairy Cattle.

OBJECTIVE: To describe the clinical findings, surgical treatment, and long-term outcome of dairy cattle undergoing partial hysterectomy with or without unilateral ovariectomy. STUDY DESIGN: Retrospective case series. ANIMALS: Dairy cattle (n = 7). METHODS: Medical records (June 2007-June 2014) of dairy cattle that had partial hysterectomy with or without ipsilateral ovariectomy were reviewed. Follow-up data were obtained by telephone interviews with owners and referring veterinarians between 6 months and 7 years following discharge. RESULTS: Seven dairy cattle met the inclusion criteria. Diagnoses made intra- or postoperatively were ovarian abscess with multiorgan adhesions (4 cows), segmental aplasia of the uterus (2 cows), and uterine lymphosarcoma (1 cow). Partial hysterectomy with or without unilateral ovariectomy was performed without surgical complications by standing flank approach. All cows were successfully discharged from the hospital (short-term prognosis). Five cows became pregnant, and 4 delivered live calves and had a satisfactory productive life without long-term complications. CONCLUSION: Partial hysterectomy by standing flank approach should be considered as a viable treatment option for unilateral ovarian or uterine problems in dairy cattle. Cattle undergoing partial hysterectomy with or without ipsilateral ovariectomy are capable of satisfactory reproduction and milk production after surgery with no short- or long-term complications.

Surgical Management of Omphalophlebitis and Long Term Outcome in Calves: 39 Cases (2008-2013).

OBJECTIVE: To describe and evaluate the surgical management of omphalophlebitis and to report the short and long term outcomes in calves. STUDY DESIGN: Retrospective case series. ANIMALS: Calves (n = 39). METHODS: Medical records (2008-2013) of calves diagnosed with omphalophlebitis and that underwent surgical correction were reviewed. Short term (hospital discharge) and long term (≥6 months after surgery) survival rates were obtained. Descriptive statistics were used to describe the population and a Fisher's exact test was used to evaluate the relationship between clinical signs, surgical management, and outcome. RESULTS: Thirty-nine calves (median age 30 days) were included in the study. Eleven calves had septic arthritis associated with omphalophlebitis and 18 had evidence of liver abscesses on ultrasound. Complete surgical en bloc resection was achieved in 18 calves and umbilical vein marsupialization was performed on the other 21 calves. Thirty-five calves were discharged from the hospital and long term followup was obtained for 30 of them. Twenty-nine animals were performing according to the owner's expectation at least 6 months after surgery (14 for marsupialization and 15 for en bloc resection). A better prognosis was detected when en bloc resection was performed (100% survival); however, when marsupialization was performed, the prognosis was good (74%; P = .05). Septic arthritis had a significant negative effect on overall survival (P < .001). CONCLUSION: The overall survival is good with both surgical options, and even calves with liver involvement and septic arthritis associated can be successfully treated with a combination of long term antibiotics and umbilical vein marsupialization.

Multiple tarsal luxations in 2 Holstein heifers.

Two Holstein heifers were referred for non-weight bearing lameness. The physical examination and radiographic findings were diagnostic of tarsal luxation. Treatment and outcome are reported. A closed reduction was successfully performed in 1 heifer. The second animal was euthanized after attempts to reduce and stabilize the joint.

Luxations multiples du tarse chez 2 taures Holstein. Deux taures Holstein ont été référées pour boiterie de non-appuie. L'examen physique et les radiographies étaient diagnostiques d'une luxation du tarse. Les traitements et pronostic sont décrits. Une réduction fermée a été possible sur une taure et l'autre a été euthanasiée après l'échec de la réduction.(Traduit par les auteurs).

Laryngeal obstruction caused by lymphoma in an adult dairy cow.

A Holstein cow was presented for inspiratory dyspnea. Endoscopic evaluation revealed swollen arytenoids and a presumptive diagnosis of bilateral arytenoidal chondritis was made. A partial arytenoidectomy was performed, the right arytenoid was submitted for histopathology, and a diagnosis of laryngeal lymphoma was made. Due to the poor prognosis, the cow was euthanized.

Obstruction laryngée causée par un lymphome chez une vache à lait. Une vache Holstein a été présentée pour dyspnée inspiratoire. L'évaluation endoscopique a révélé une enflure des aryténoides. Une hypothèse diagnostique de chondrite des aryténoides a été émise. Une aryténoidectomie partielle a été effectuée. L'aryténoide droit a été soumis pour évaluation histopathologique. Un diagnostic de lymphome laryngé a été émis. Le pronostic d'un lymphome étant sombre, la vache a été euthanasiée.(Traduit par les auteurs).

Epidemiology of Salmonella enterica subspecies enterica serotypes, isolated from imported, farmed and feral poultry in the Cayman Islands.

Non-typhoidal Salmonellae (NTS) are common foodborne pathogens throughout the world causing acute gastroenteritis. Compared to North America and Europe, there is little information on NTS in the Caribbean. Here we investigated the prevalence and characteristics of NTS present in the local poultry of the Cayman Islands to determine the public health risk. In total, we collected 156 samples. These were made up of boot swabs of 31 broiler farms and 31 layer farms (62 samples), paper bedding from 45 imported chick boxes, and 49 pooled cecum samples from feral chickens, each sample representing 10 individual chickens. Salmonella was isolated using the ISO 6579 protocol and isolates were characterized using Whole Genome Sequencing (WGS) analysis. Eighteen Salmonella isolates were obtained and comprised six S. enterica subspecies enterica serotypes and one subspecies houtenae serotype. Serotypes were: S. Kentucky (n = 9), S. Saintpaul (n = 5), S. Javiana (n = 1), S. Senftenberg (n = 1), S. Poona (n = 1) and S. Agona (n = 1). S. Kentucky strains were all ST152 and clonally related to poultry strains from the United states. S. Saintpaul ST50 strains showed clonality to North American strains. Over half of the strains (n = 11) contained resistance genes to at least two antibiotic groups and five strains were MDR, mainly those from imported day-old chicks. The blaCMY-2 gene was found in S. Kentucky from day-old chicks. Strains from feral poultry had no acquired AMR genes. While serotypes from feral poultry have been identified in human infections, they pose minimal risk due to their low virulence.

Milk flow obstruction caused by varicose vein of the teat in dairy cattle.

OBJECTIVE: To describe varicose vein as a cause of obstruction of the teat cistern in dairy cattle and to report therapeutic options and outcome. STUDY DESIGN: Retrospective case series. ANIMALS: Dairy cows (n = 22). METHODS: Medical records (1998-2011) of dairy cows admitted for milking difficulties caused by a teat varicose vein were reviewed. Three treatment approaches were used: sclerotherapy, ligation of the vein associated with sclerotherapy, and phlebectomy. Long-term outcome was obtained ≥ 6 months after treatment and defined as a milking improvement. Descriptive statistics were used to determine the population at risk and a chi square test was used to evaluate the relationship between treatments and outcomes. RESULTS: Twenty-four teats (22 cows) had a varicose vein. Forequarters were more frequently affected than rear quarters (P < .01). Three sclerotherapies, 12 ligations associated with sclerotherapy and 6 phlebectomies were performed. Five veins were not treated. Overall prognosis with treatment was good (84%) at ≥ 6 months and was not significantly different between treatment types (P = .38). Recurrence of the obstruction by the varicose vein occurred in 3 of 19 teats. CONCLUSIONS AND CLINICAL RELEVANCE: Several surgical options are available for treatment of teat varicose veins. The overall prognosis of return to normal milking is good.

Barriers and facilitators to implementing a new regulation restricting antimicrobial use in dairy production in Québec, Canada: A qualitative study.

With the emergence of antimicrobial resistance (AMR), many countries are implementing restrictive regulations to reduce antimicrobial use (AMU) in animal production. Although these measures are effective at the national level, their implementation may generate challenges for producers and veterinarians. The objective of this study was to explore the barriers and facilitators of implementing a new regulation restricting the use of antimicrobials of very high importance for human health in the dairy production sector in the province of Québec, Canada. Individual interviews were conducted with fifteen veterinarians and twenty-seven dairy producers. Thematic analysis was performed based on the COM-B model of behavior change (capability-opportunity-motivation-behavior). Our results indicated that the lack of availability of alternative treatments, the long delays related to diagnostic tests and the fear of economic consequences were major barriers to the implementation of the regulation. A small number of producers also perceived that the regulation negatively impacted the health and wellbeing of their animals. Additionally, participants acknowledged the importance of early education and training to better understand the purpose of the regulation and increase its acceptability. Lastly, most participants reported that they had not only reduced their use of antimicrobials of very high importance for human health following the regulation, but they had also increased preventive practices on their farm. This study reveals that the implementation of restrictive regulations to reduce AMU in animal production can lead to multiple challenges in practice. Our results highlight the need for better communication and training of producers and veterinarians before and during the implementation of similar regulations in the future and underline the importance of measuring the direct and indirect impacts of those regulations on productivity and on animal health and wellbeing.

Clonal and plasmidic dissemination of critical antimicrobial resistance genes through clinically relevant ExPEC and APEC-like lineages (ST) in the dairy cattle population of Québec, Canada.

Antimicrobial resistance can be effectively limited by improving the judicious use of antimicrobials in food production. However, its effect on the spread of AMR genes in animal populations is not well described. In the province of Québec, Canada, a new legislation implemented in 2019 has led to an unprecedented reduction in the use of critical antimicrobials in dairy production. We aimed to investigate the potential link between ESBL/AmpC E. coli isolated before and after legislation and to determine the presence of plasmids carrying genes responsible for critical AMR. We collected fecal samples from calves, cows, and manure pit from 87 Québec dairy farms approximately 2 years before and 2 years after the legislation came into effect. The whole genomes of 183 presumptive ESBL/AmpC E. coli isolated after cefotaxime enrichment were sequenced. Their phylogenetic characteristics (MLST, serogroup, cgMLST) and the presence of virulence and resistance genes and replicons were examined. A maximum likelihood phylogenetic tree was constructed based on single nucleotide polymorphism (SNPs). We identified 10 clonal lineages (same cgMLST) and 7 clones (SNPs ≤ 52). Isolates belonging to these clones could be found on different farms before and after the legislation, strongly suggesting a clonal spread of AMR genes in the population during this 4-year period. All isolates were multidrug resistant (MDR), with clone 2 being notable for the presence of macrolide, fluoroquinolone, and third-generation cephalosporin resistance genes. We also identified clinically relevant ExPEC (ST10) and APEC-like lineages (ST117, ST58, ST88) associated with the presence of ExPEC and APEC virulence genes, respectively. Our data also suggests the presence of one epidemic plasmid belonging to the IncY incompatibility group and carrying qnrs1 and blaCTX-M-15. We demonstrated that AMR genes spread through farms and can persist over a 4-year period in the dairy cattle population through both plasmids and E. coli clones, despite the restriction of critical antimicrobial use. MDR ExPEC and APEC-like STs are present in the normal microbiota of cattle (more frequently in calves). These data increase our knowledge on gene dissemination dynamics and highlight the fact that biosecurity measures should be enhanced in this industry to limit such dissemination.

Evidence of a decrease in sales of antimicrobials of very high importance for humans in dairy herds after a new regulation restricting their use in Quebec, Canada.

In the province of Quebec, Canada, a new regulation restricting usage of antimicrobials of very high importance for human health (Health Canada: category 1 antimicrobials) in production animals is effective since February 2019. The objective of this study was to estimate changes in AM sales in dairy herds after the implementation of the regulation. Therefore, invoice data were extracted from veterinary software, Vet-Expert, used by most dairy veterinarians in the province of Quebec, and antimicrobial quantities were transformed in Canadian defined course doses for cattle (DCDbovCA). The sum of antimicrobials sales monthly in each herd was estimated in DCDbovCA from June 2016 to May 2020. To evaluate the herd-level change in AM sales and the impact of different factors, the number of DCDbovCA by herd from June 2017 to May 2018 (pre-regulation period) were compared with those of June 2019 to May 2020 (post-regulation period). Total category 1 AM sales of 3,569 Quebec's herds went from a range of 14,258 to 21,528 DCDbovCA/month to a range of 1,494 to 4,707 DCDbovCA/month after the implementation of the new regulation. Moreover, using data from 3,337 herds, we estimated a mean (95% confidence interval) reduction in 19 DCDbovCA/herd-year (14.8, 24.2), while the pre-regulation herd-level category 1 AM sales was 26 DCDbovCA/herd-year. This reduction was achieved without evidence of an increase in other antimicrobials. Finally, the veterinary facility associated with the herd was an important determinant of the herd-level reduction in category 1 antimicrobials. This study was the first to quantify a significant reduction in category 1 AM sales following the implementation of a restrictive regulation in dairy production in Canada. These results demonstrate that such an approach is effective to reduce the sales of a specific category of antimicrobial in animal production.

Impact of a Regulation Restricting Critical Antimicrobial Usage on Prevalence of Antimicrobial Resistance in Escherichia coli Isolates From Fecal and Manure Pit Samples on Dairy Farms in Québec, Canada.

To tackle antimicrobial resistance (AMR), one of the major health threats of this century, the World Health Organization (WHO) endorsed a global action plan in 2015. This plan calls countries to develop national actions to address AMR. The province of Québec, Canada, adopted a new regulation on the 25th of February 2019, to limit the use in food animals of antimicrobials of very high importance in human medicine. We aimed to establish the impact of this regulation by comparing the AMR situation in dairy cattle in Québec ~2 years before and 2 years after its introduction. We sampled calves, cows, and the manure pit in 87 farms. Generic and putative ESBL/AmpC E. coli were tested for susceptibility to 20 antimicrobials. Logistic regression was used to investigate whether the probability of antimicrobial resistance differed between isolates obtained from the pre and post regulation periods by sample type (calves, cows, manure pit) and in general. To identify AMR genes dissemination mechanisms, we sequenced the whole genome of 15 generic isolates. In the generic collection, at the herd level, the proportion of multidrug resistant (MDR) isolates, decreased significantly from 83 to 71% (p = 0.05). Folate inhibitor and aminoglycoside resistances demonstrated a significant decrease. However, when analyzed by sample type (calves, cows, manure pit), we did not observe a significant AMR decrease in any of these categories. In the ESBL/AmpC collection, we did not detect any significant difference between the two periods. Also, the general resistance gene profile was similar pre and post regulation. We identified both clonal and plasmidic dissemination of resistance genes. In conclusion, as early as 2 years post regulation implementation, we observed a significant decrease in MDR in the dairy industry in Quebec in the generic E. coli collection with folate inhibitor and aminoglycoside resistances showing the most significant decrease. No other significant decreases were yet observed.

Repair of transverse process fractures of multiple lumbar vertebrae in an adult dairy cow.

OBJECTIVE: To report lumbar vertebrae transverse process fracture repair using a narrow 3.5 mm limited contact dynamic compression plate (LC-DCP) in an adult dairy cow. STUDY DESIGN: Case report. ANIMALS: A 3-year-old Holstein cow. METHODS: Under general anesthesia, fractured left transverse processes of lumbar vertebrae 2-4 were repaired using internal fixation. A narrow 3.5 mm LC-DCP was contoured and secured to the spinous process and the transverse process of each fractured vertebra. RESULTS: Fractured transverse processes of the lumbar vertebrae were successfully repaired and the cow discharged 10 days after surgery. At 10 months after surgery, the cow was declared reserved champion at a regional show. CONCLUSION: A paramedian approach and muscle splitting can be used to repair multiple lumbar transverse process fractures using internal fixation with an excellent cosmetic outcome.

Comparison of Quantification Methods to Estimate Farm-Level Usage of Antimicrobials Other than in Medicated Feed in Dairy Farms from Québec, Canada.

The objective of the study was to compare three quantification methods to a "garbage can audit" (reference method, REF) for monitoring antimicrobial usage (AMU) from products other than medicated feed over one year in 101 Québec dairy farms. Data were collected from veterinary invoices (VET method), from the "Amélioration de la Santé Animale au Québec" provincial program (GOV method), and from farm treatment records (FARM method). The AMU rate was reported in a number of Canadian Defined Course Doses for cattle (DCDbovCA) per 100 cow-years. Electronic veterinary sales data were obtained for all farms for VET and GOV methods. For the FARM method, a herd management software was used by 68% of producers whereas farm treatment records were handwritten for the others; records could not be retrieved in 4% of farms. Overall, agreement was almost perfect between REF and VET methods (concordance correlation coefficient (CCC) = 0.83), but moderate between REF and GOV (CCC = 0.44), and between REF and FARM (CCC = 0.51). Only a fair or slight agreement was obtained between any alternative method of quantification and REF for oral and intrauterine routes. The billing software used by most of Québec's dairy veterinary practitioners seems promising in terms of surveillance and benchmarking of AMU in the province.