Sensitivity and specificity of mobility scoring for the detection of foot lesions in pasture-based Irish dairy cows.

Lameness is an important production disease in dairy cows worldwide and has detrimental effects on cows' welfare, production, and reproductive performance, thus affecting the sustainability of dairy farming. Timely and effective detection of lameness allows for effective treatment, minimizing progression of disease, and maximizing the prognosis of recovery. Mobility scoring (MSc) is a 4 point (0-3) visual lameness scoring system that is the industry standard in several countries. However, few studies have examined the sensitivity (Se) and specificity (Sp) of MSc to detect foot lesions. The aim of this observational study was to determine the Se and Sp of MSc to detect foot lesions in dairy cattle in a pasture-based system. Five hundred ninety-five primi- and multiparous cows were randomly selected from 12 commercial Irish dairy farms and recruited for the study. Recruited cows were mobility scored and passed through a foot-paring crate where all 4 feet were lifted for examination. The team recorded the anatomical location and severity of any foot lesions present based on appearance only. Then, based on the type and severity of the lesions present, cows were classified according to 3 case definitions case definition 1: Any lesion present; case definition 2: Moderate lesions present (excluding minor lesions expected to have a low probability of affecting gait); and case definition 3: Severe lesions present (only including lesions most likely to result in a detectable gait abnormality). Sensitivity and Sp of MSc was calculated based on a threshold of MSc ≥2, defined as impaired (MSc = 2) or severely impaired (MSc = 3) mobility for each of the 3 case definitions, at the overall level and disaggregated by parity. The overall cow-level lesion prevalence based on the case definition 1 was 0.54 with significant between-herd variation. The overall Se and Sp of MSc for the detection of foot lesions were 0.18 and 0.96, 0.35 and 0.94, 0.43 and 0.94 for the case definitions 1, 2, and 3, respectively. Our findings showed poor Se, but high Sp of MSc for the detection of cows with foot lesions in a pasture-based system.

Diagnosis of respiratory disease in preweaned dairy calves using sequential thoracic ultrasonography and clinical respiratory scoring: Temporal transitions and association with growth rates.

Bovine respiratory disease (BRD) in dairy calves is a multifactorial condition, involving environmental, host, and pathogen factors. Thoracic ultrasound scoring (TUS) has recently been validated as an accurate method of detecting BRD-related lung pathology in dairy calves. Previous studies investigating the use of TUS in preweaned dairy calves have largely been based on cross-sectional data from all-year production systems. The objectives of this longitudinal observational study were to characterize the temporal transitions in TUS scores in dairy calves from pasture-based, seasonal-calving herds using sequential examinations during the preweaning period, and to investigate the relationship between the presence and temporal pattern of BRD, diagnosed by TUS or clinical respiratory scoring (CRS), and average daily gain (ADG). In spring of 2019, 317 preweaned calves from 7 commercial dairy farms were recruited at less than 4 wk old (ranging from 1-27 d of age). Each farm was examined on at least 3 occasions at 20- to 28-d intervals and housed indoors in group or individual pens. At each visit TUS scores, CRS scores based on the University of Wisconsin Calf Respiratory Score Chart (https://www.vetmed.wisc.edu/fapm/wp-content/uploads/2020/01/calf_respiratory_scoring_chart.pdf), and live weight using a dairy breed-specific weigh band were recorded. All data were recorded by the same 2 veterinarians over the course of the study. The final data set consisted of 966 TUS and CRS scores collected from 317 calves over a period of approximately 6 wk from 7 farms. The data were analyzed in multivariable, mixed effects, linear regression models, with separate models constructed for TUS and CRS scores. Random effects (intercepts) were included for calf, farm, and visit week. Additionally, a random slope was included for age at sampling by farm. Median farm TUS score ranged from 0 to 2.5 over the 3 visits (possible range: 0-5). The percentage of calves with a TUS score ≥3 (consolidation of the full thickness of 1 lung lobe), on each farm ranged from 0 to 50%. The median CRS in calves on individual farms ranged from 1 to 3 over the 3 visits (possible range: 0-12). The percentage of calves on each farm with a CRS score ≥5 (possible range: 0-12) ranged from 0 to 26%. The TUS and CRS scores were weakly correlated. The TUS was associated with reduced ADG. Calves with TUS scores ≥3 grew at 126 g/d less than unaffected calves over the 3-wk period before examination. The predicted effect on ADG was dependent on the age and duration over which the animal was affected. Calves affected later (i.e., between visits 2 and 3) had lower predicted weights at 63 d compared with calves with increased TUS scores earlier in the study period. Calves with a TUS score ≥3 at each of the 3 sampling points had the lowest weight at 63 d of age. There was no association of CRS with ADG. This study showed that in contrast to CRS, higher TUS scores are associated with lower ADG, with weight loss being more pronounced in chronic cases.

An unusual presentation of developmental anomalies of the cardiovascular system including tetralogy of fallot, double outlet right ventricle, patent foramen ovale and persistent right aortic arch in a Friesian calf.

BACKGROUND: Congenital heart diseases are occasionally encountered in the bovine species. Ventricular septal defects (VSD) and atrial septal defects (ASD) are reported to be the most common; however, a vast collection have been reported [1, 2]. Congenital heart diseases is thought to represent less than 3% of all congenital abnormalities in calves [3]. Various cardiac anomalies arise due to defective embryologic development such as defects of the septae or the cardiac chambers [2]. The exact aetiology of these congenial heart anomalies remains to be fully elucidated [4]. VSDs appear to be the most common congenital cardiac anomaly in calves. Other diseases can be subdivided into cyanotic (e.g. ASD or patent ductus arteriosus) and non-cyanotic (e.g. tetralogy of fallot or eisenmengers complex) [5, 6]. An exceptional presentation of an array of congenital anomalies was identified in a Friesian heifer calf. To the authors' knowledge this concurrent collection of congenital abnormalities has never been reported in this species. CASE PRESENTATION: A 3-day old Friesian heifer presented with a history since birth of regurgitation post feeding. The main finding on clinical examination was tachypnoea with a holosystolic murmur. Echocardiography identified a VSD, patent foramen ovale (PFO) (both with left to right blood flow) and tricuspid insufficiency. The calf was subsequently euthanised and underwent gross post-mortem examination. A persistent right aortic arch (PRAA) was identified. The cardiac anomalies identified on the echocardiogram were confirmed along with additional abnormalities; double outlet right ventricle (DORV), partial transposition of the great vessels, pulmonic stenosis, hypoplasia of the right branch of the pulmonary artery and right ventricular hypertrophy. The final diagnosis was Tetralogy of Fallot with DORV, PFO and PRAA. The lungs appeared oedematous and congested due to cardiac malfunction and cranioventral aspiration pneumonia. Free serous fluid was identified in the thoracic cavity. Unilateral renal agenesis of the left kidney was an incidental finding but is of note due to its coexistence with the cardiac abnormalities. CONCLUSIONS: This is an unusual case as it features numerous congenital abnormalities that appeared to negate each other allowing capability with life. To the authors' knowledge, this collection of concurrent cardiac anomalies has not been previously reported in bovines.

Using examination performance data and focus groups to inform teaching - a case study from final year students of veterinary medicine.

BACKGROUND: Student feedback has played an important role in the maintenance of quality and standards in higher education. Perhaps the most commonly used method to capture feedback is a series of questions or statements where students indicate their degree of satisfaction or agreement. Focus groups offer an alternative means of capturing 'richer' qualitative data relating to students' thoughts on course structure. Aside from student evaluations, student examination performance has been used as a method to evaluate the efficacy of curriculum changes at programme level. However, this data is utilised less so at a 'finer detail' level to identify specific issues with the delivery of teaching. CASE PRESENTATION: The purpose of this report was to outline the approach taken using qualitative and quantitative data to identify problems with a specific area of teaching, inform a new teaching approach and to assess the impact of those changes. Following quantitative and qualitative analysis, a practical class on dairy herd fertility performance was highlighted as an area for improvement. After the introduction of the newly formatted practical class with a greater focus on self-directed learning, there was a significant increase in the average score (p < 0.001) and a decrease in the proportion of students failing (p < 0.001) the question that assessed the analysis of dairy herd fertility data. In addition, the R-squared value between students' performance in the fertility question and their performance in the overall examination increased from 0.06 to 0.11. CONCLUSIONS: The combination of qualitative focus group data and quantitative analysis of examination performance data represent robust methods for identifying problems associated with specific aspects of veterinary teaching.

Health-associated changes of the fecal microbiota in dairy heifer calves during the pre-weaning period.

Introduction: Neonatal calf diarrhea is a multifactorial condition that occurs in early life when calves are particularly susceptible to enteric infection and dysbiosis of the gut microbiome. Good calf health is dependent on successful passive transfer of immunity from the dam through colostrum. There are limited studies on the developing gut microbiota from birth to weaning in calves. Methodology: Therefore, the objective of this study was to examine the effect of immune status and diarrheal incidence on the development of the fecal microbiota in Jersey (n = 22) and Holstein (n = 29) heifer calves throughout the pre-weaning period. Calves were hand-fed a colostrum volume equivalent to 8.5% of their birthweight, from either the calf's dam (n = 28) or re-heated mixed colostrum (≤2 cows, ≤1d; n = 23) within 2 h of birth. All calves were clinically assessed using a modified Wisconsin-Madison calf health scoring system and rectal temperature at day (d) 0, d7, d21, or disease manifestation (DM) and weaning (d83). Weights were recorded at d0, d21, and d83. Calf blood samples were collected at d7 for the determination of calf serum IgG (sIgG). Fecal samples were obtained at d7, d21/DM [mean d22 (SE 0.70)], and at weaning for 16S rRNA amplicon sequencing of the fecal microbiota. Data were processed in R using DADA2; taxonomy was assigned using the SILVA database and further analyzed using Phyloseq and MaAsLin 2. Results and discussion: Significant amplicon sequence variants (ASVs) and calf performance data underwent a Spearman rank-order correlation test. There was no effect (p > 0.05) of colostrum source or calf breed on serum total protein. An effect of calf breed (p < 0.05) was observed on sIgG concentrations such that Holstein calves had 6.49 (SE 2.99) mg/ml higher sIgG than Jersey calves. Colostrum source and calf breed had no effect (p > 0.05) on health status or the alpha diversity of the fecal microbiota. There was a relationship between health status and time interaction (p < 0.001), whereby alpha diversity increased with time; however, diarrheic calves had reduced microbial diversity at DM. No difference (p > 0.05) in beta diversity of the microbiota was detected at d7 or d83. At the genus level, 33 ASVs were associated (adj.p < 0.05) with health status over the pre-weaning period.

Investigation into the safety, and serological responses elicited by delivery of live intranasal vaccines for bovine herpes virus type 1, bovine respiratory syncytial virus, and parainfluenza type 3 in pre-weaned calves.

Despite the fact that pneumonia remains a leading cause of mortality and morbidity in pre-weaned calves, relatively little is known regarding the effects of the concurrent administration of intranasal pneumonia virus vaccines, particularly in calves with high levels of maternally derived antibodies. The objective of this study was to use a cohort of 40 dairy and dairy-beef female and male calves (27 females and 13 males) to determine serological responses to concurrent administration at 3 weeks of age (22 ± 4.85 days) of two commercially available intranasal (IN) vaccines for the viruses: bovine respiratory syncytial virus (BRSV), bovine herpes virus 1 (BoHV-1), and parainfluenza-3-virus (PI3-V). The study groups were as follows: (i) Bovilis IBR Marker Live only® (IO), (ii) Bovilis INtranasal RSP Live® only (RPO), (iii) Concurrent vaccination with Bovilis IBR Marker Live® & Bovilis Intranasal RSP Live® (CV), and (iv) a control group of non-vaccinated calves (CONT). The calves' serological response post-IN vaccination, clinical health scores, rectal temperatures, and weights were measured. Data were analyzed in SAS using mixed models and logistic regression. The CV calves had an average daily weight gain (ADG) of 0.74 (±0.02) kg, which was similar to CONT (0.77 ± 0.02 kg). Despite no significant differences in the antibody levels between study groups 3 weeks post-IN vaccination, following the administration of subsequent parenteral injections in the form of Bovilis Bovipast RSP®(antigens; inactivated BRSV, inactivated PI3-V, inactivated Mannheimia haemolytica) and Bovilis IBR Marker Live®, the antibody levels of the BRSV and PI3-V increased in both the CV and RPO study groups. Concurrent vaccination resulted in no increase in fever and no difference in health scores when compared to CONT.

Survey of farm, parlour and milking management, parlour technologies, SCC control strategies and farmer demographics on Irish dairy farms.

BACKGROUND: This cross-sectional study describes a survey designed to fill knowledge gaps regarding farm management practices, parlour management practices and implemented technologies, milking management practices, somatic cell count (SCC) control strategies, farmer demographics and attitudes around SCC management on a sample of Irish dairy farms. RESULTS: We categorized 376 complete responses by herd size quartile and calving pattern. The average respondent herd was 131 cows with most (82.2%) operating a seasonal calving system. The median monthly bulk tank somatic cell count for seasonal calving systems was 137,000 cells/ml (range 20,000 - 1,269,000 cells/ml), 170,000 cells/ml for split-calving systems (range 46,000 - 644,000 cells/ml) and 186,000 cells/ml for 'other' herds (range 20,000 - 664,000 cells/ml). The most common parlour types were swing-over herringbones (59.1%) and herringbones with recording jars (22.2%). The average number of units across herringbone parlours was 15, 49 in rotary parlours and two boxes on automatic milking system (AMS) farms. The most common parlour technologies were in-parlour feeding systems (84.5%), automatic washers on the bulk tank (72.8%), automatic cluster removers (57.9%), and entrance or exit gates controlled from the parlour pit (52.2%). Veterinary professionals, farming colleagues and processor milk quality advisors were the most commonly utilised sources of advice for SCC management (by 76.9%, 50.0% and 39.2% of respondents respectively). CONCLUSIONS: In this study, we successfully utilised a national survey to quantify farm management practices, parlour management practices and technology adoption levels, milking management practices, SCC control strategies and farmer demographics on 376 dairy farms in the Republic of Ireland. Rotary and AMS parlours had the most parlour technologies of any parlour type. Technology add-ons were generally less prevalent on farms with smaller herds. Despite finding areas for improvement with regard to frequency of liner changes, glove-wearing practices and engagement with bacteriology of milk samples, we also found evidence of high levels of documentation of mastitis treatments and high use of post-milking teat disinfection. We discovered that Irish dairy farmers are relatively content in their careers but face pressures regarding changes to the legislation around prudent antimicrobial use in their herds.

GlnH, a Novel Antigen That Offers Partial Protection against Verocytotoxigenic Escherichia coli Infection.

Verotoxin-producing Escherichia coli (VTEC) causes zoonotic infections, with potentially devastating complications, and children under 5 years old are particularly susceptible. Antibiotic treatment is contraindicated, and due to the high proportion of infected children that suffer from severe and life-changing complications, there is an unmet need for a vaccine to prevent VTEC infections. Bacterial adhesins represent promising candidates for the successful development of a vaccine against VTEC. Using a proteomic approach to identify bacterial proteins interacting with human gastrointestinal epithelial Caco-2 and HT-29 cells, we identified eleven proteins by mass spectrometry. These included a glutamine-binding periplasmic protein, GlnH, a member of the ABC transporter family. The glnH gene was identified in 13 of the 15 bovine and all 5 human patient samples tested, suggesting that it is prevalent. We confirmed that GlnH is involved in the host cell attachment of an O157:H7 prototype E. coli strain to gastrointestinal cells in vitro. Recombinant GlnH was expressed and purified prior to the immunisation of mice. When alum was used as an adjuvant, GlnH was highly immunogenic, stimulating strong serological responses in immunised mice, and it resulted in a modest reduction in faecal shedding but did not reduce colonisation. GlnH immunisation with a T-cell-inducing adjuvant (SAS) also showed comparable antibody responses and an IgG1/IgG2a ratio suggestive of a mixed Th1/Th2 response but was partially protective, with a 1.5-log reduction in colonisation of the colon and caecum at 7 days relative to the adjuvant only (p = 0.0280). It is clear that future VTEC vaccine developments should consider the contribution of adjuvants in addition to antigens. Moreover, it is likely that a combined cellular and humoral response may prove more beneficial in providing protective interventions against VTEC.

Correction: Quinn et al. GlnH, a Novel Antigen That Offers Partial Protection against Verocytotoxigenic Escherichia coli Infection. Vaccines 2023, 11, 175.

In the original publication [...].

The new Veterinary Medicines Regulation: rising to the challenge.

This article focuses on the new Veterinary Medicines Regulation, which is applicable across all Member States of the European Union, including Ireland, from 28 January 2022. From this date, prophylactic use of antimicrobials (AMs) in groups of animals is banned, metaphylactic use in groups of animals is restricted, and certain AMs are reserved for humans only. In the Irish dairy industry, as elsewhere, successful implementation of the Regulation will require a high level of mastitis control across all herds, and measures to support high standards in antibiotic stewardship. National actions will be critical, to support optimal mastitis control throughout the national herd. For private veterinary practitioners (PVPs), the Regulation will lead to specific prescribing changes, including the requirement to shift from blanket to selective dry cow therapy. Further, prescribing choices will need to be guided by the categorisation for AMs developed by the European Medicines Agency (EMA). More broadly, the Regulation requires a fundamental shift in thinking both in terms of AM usage and of the role of the PVP. Given the close association between mastitis control and intramammary AM stewardship, it is imperative that prescribing and mastitis control decisions are made concurrently. A herd health approach will be critical, within a Client-Patient-Practice Relationship as outlined by the Veterinary Council of Ireland. On those farms with sub-optimal mastitis control, mastitis issues need to be sustainably resolved. A detailed farm investigation by the PVP, in partnership with the farmer and other milk quality professionals, is essential, to understand the epidemiology and on-farm drivers of mastitis, to develop farm-specific action plans, and to facilitate ongoing monitoring of progress. It is vital that PVPs provide leadership, with the provision of a holistic, herd health approach to inform both prescribing and mastitis control decisions in herds under their care.

Intramammary antimicrobial sales in Ireland: a 2020 descriptive update.

Intramammary (IM) antimicrobial sales data are currently the only feasible means to gain broad insights into on-farm usage of antimicrobials (AMs) relevant to mastitis control within the Irish dairy industry. The aim of this study was to update earlier work describing sales data of intramammary antimicrobial usage in the Irish dairy industry in 2020. Previously reported data from 2013 to 2019 is included for reference and 2020 sales data is reported using similar methodology to previously published work in this area. Data on IM AMs sold in Ireland during 2013-2020 were obtained from two sources, believed to represent 99% of all sales of IM AMs in Ireland, and analyses were undertaken to evaluate patterns in IM AM sales. We report an increase in overall sales of both lactating cow (LC) and dry cow (DC) IM AMs. We observed a large increase in the use of DC IM AMs, from 0.95 to 1.13 defined course dose (DCDvet) per cow per year in 2019 and 2020 respectively, as well as evidence of ongoing usage of highest priority critically important AMs, as defined by the World Health Organization. There was also a slight increase in LC use of IM AMs, from 0.43 to 0.44 defined course dose (DCDvet) per cow per year. We believe that our results provide an accurate reflection of IM sales in Ireland in 2020. In common with any study of this type, caution is needed when interpreting national IM AM sales data, noting the potential discrepancies between AM sales and on-farm usage. Nonetheless, the sales pattern described here, most importantly the increased use of DC products and ongoing and increasing use of HP CIA products in both DC and LC therapy raise significant concerns for the Irish dairy industry. This study provides an evidence base to inform current policy discussions, particularly in the context of the new Veterinary Medicines Regulation (Regulation (EU) 2019/6), which comes into force on 28 January 2022.

Prescribing and sales of intramammary antimicrobials in Ireland in 2019 and 2020: the role of milk purchasers.

BACKGROUND: In Ireland between 2008 and 2022, intramammary antimicrobial (AM) products could be prescribed by a veterinary practitioner under what was known as Schedule 8 (or remote) prescribing. Under this prescribing route, an annual herd visit was not required when criteria were met as outlined in Animal Remedies Regulation 2007 to 2017 (statutory instruments No. 786/2007 and 558/2017). Under this prescribing route, the responsibilities of the milk purchaser, the farmer and the veterinary practitioner were each outlined, and a written mastitis control programme (MCP) was required. Milk purchasers implemented MCPs on participating farms (so-called MCP herds) with support from veterinary practitioner(s) who undertook Schedule 8 prescribing of intramammary AM tubes. This study seeks a clearer understanding of the role of milk purchasers in the prescribing and sale of intramammary AM products in Ireland during 2019 and 2020, whilst this Regulation was in force. Specifically, the study sought insights into the role of milk purchasers in the prescribing and sale of intramammary AM products in the Irish dairy industry during 2019 and 2020, using anonymised and highly aggregated milk purchaser data. The study also provided insights into milk quality among supplying herds during this period. METHODS: For this study, we had access to anonymised, highly aggregated data from all milk purchasers that operated a MCP on at least some of their supplying herds during 2019 or 2020. Data collection was undertaken by the Department of Agriculture, Food and Marine. Data analysis was primarily descriptive. RESULTS: Data were available on 11 milk purchasers (64.7% of all) and 13,251 supplying herds. Of these, 52% were MCP herds. The quality of milk from supplying herds varied significantly by month, year and milk purchaser. During 2019 and 2020, there was a single Schedule 8 prescriber (a private veterinary practitioner prescribing intramammary AMs as part of a MCP), on average, for 549.3 herds. The sale of intramammary AM products through milk purchasers represented 15.2% and 26.9% of national sales in in-lactation and dry cow tubes, respectively. There was an overall 2% increase in sales through milk purchasers between 2019 and 2020. Few European Medicines Agency (EMA) category B ('Restrict') intramammary AM products were sold by milk purchasers. For both in-lactation and dry cow tubes, there was a statistically significant association between EMA classification and route of sale (through milk purchasers or otherwise). CONCLUSIONS: The study findings provide important insights into mastitis control and intramammary AM stewardship in the Irish dairy industry. Significant differences between milk purchasers were observed in the quality of milk, as measured through somatic cell count (SCC) values, from supplying herds. This warrants further research. In the context of intramammary AM prescribing, veterinary oversight under the Animal Remedies Regulation 2007 to 2017 was very limited during 2019 and 2020. There were also significant associations between EMA classification and route of sale during 2019 and 2020, reinforcing the need for Irish veterinary practitioners to move away from EMA category B intramammary AMs. Higher quality data are needed to address important industry questions. Specifically it is recommended that national bulk tank SCC data are made available for public good research. Past experiences with Schedule 8 prescribing (no longer permitted from 28 January 2022) may influence current efforts towards improved intramammary AM stewardship.

Mastitis Control and Intramammary Antimicrobial Stewardship in Ireland: Challenges and Opportunities.

The Veterinary Medicines Regulation (EU 2019/6) came into force in all EU member states on 28 January 2022. This regulation places particular emphasis on prudent and responsible antimicrobial use in food animal production. Key changes include restrictions on the prophylactic use of antimicrobials in animals, and the possibility to reserve certain antimicrobials for humans only. The Regulation presents challenges to the Irish dairy industry, particularly with respect to current approaches to dry cow therapy. In response, the CellCheck technical working group (TWG, a technical group working in support of CellCheck, the national mastitis control programme) have developed pragmatic national and farm-level recommendations in support of improved mastitis control and intramammary antimicrobial stewardship in the Irish dairy industry. This paper outlines these recommendations, and provides an overview of the evidence considered to inform the TWG during its work (including the Regulation, policy perspectives, international best-practice, international scientific reviews and specific Irish challenges). In many key areas of concern, the TWG recognises the challenges in seeking to shape recommendations in the absence of robust and practical scientific evidence. For this reason, some of the recommended actions are pragmatic in nature, informed by national and international experiences. Periodic programme review will be needed, informed by ongoing monitoring of key performance indicators, to identify those actions that are most effective in an Irish context.

Trends in estimated intramammary antimicrobial usage in the Irish dairy industry from 2003 to 2019.

The objective of this study is to update earlier work on intramammary (IM) antimicrobial (AM) usage in Ireland. There is a need to measure AM usage in food-producing animals given increasing societal concerns about AM resistance as well as recent regulatory changes that dictate changes in how AM are used in food-producing animals and how AM sales and usage are recorded. National sales data were collected and used in this analysis. Sales of the number of IM AM tubes and amount of active ingredient sold were analyzed each year by product type [in-lactation (LC) therapy and dry cow (DC) therapy] and classification system (World Health Organization and more recent European Medicine Agency). Descriptive trends in estimated IM AM use are presented, including defined course dose (DCDvet; a technical unit for on-farm usage). There has been a decrease in estimated on-farm usage of IM AM during lactation, from 0.48 DCDvet/cow per year in 2015 to 0.43 DCDvet/cow per year in 2019. Almost all LC therapies sold include critically important AM (CIA), with 98% of the total DCDvet administered for LC therapy in 2019 containing at least 1 CIA. There has been a slow increase in tubes containing at least 1 highest priority CIA in LC therapies, from 0.01 DCDvet/cow per year in 2003, accounting for 2% of the total DCDvet administered for LC therapy, to 0.03 DCDvet/cow per year in 2019, accounting for 7% of the total DCDvet administered for LC use. The estimated usage of IM AM DC therapy has decreased from 1.09 DCDvet/cow per year in 2015 to 0.95 DCDvet/cow per year in 2019. In the last 5 yr, more than 40% of the total DC DCDvet administered contained at least 1 CIA, and there has been an increase in recent years in the percentage of the total DC DCDvet administered that contains at least 1 highest priority CIA, driven mainly by use of fourth-generation cephalosporin. This work provides further insights into IM AM usage in Ireland and highlights some important areas for attention, including availability of farm-level usage data, prescribing practices, and usage of important AM.

Engaging with selective dry cow therapy: understanding the barriers and facilitators perceived by Irish farmers.

BACKGROUND: Selective dry cow therapy (SDCT) is widely promoted in dairy farming as a method to reduce antimicrobial usage. New legislation introduced by the European Union will restrict and regulate the prophylactic and metaphylactic use of antibiotics from January 2022. Blanket dry cow therapy continues to be a practice engaged in by many farmers in Ireland and for many of these farmers, moving towards SDCT would require a significant infrastructural, behavioural and/or cultural change on their farm. Existing research has reported the important need to understand farmers' motivations to initiate any substantial behaviour change. However, it is currently unknown what farmers know, think and believe about SDCT in Ireland. The aim of this study was to use qualitative methods to explore what barriers and facilitators farmers perceived to exist with SDCT and explore if they had chosen to implement SDCT after voluntarily participating in a funded dry cow consult with a trained veterinarian, with the objective of maximising the dry period udder health performance and moving safely to SDCT. RESULTS: In this study, 19 farmers were contacted, and telephone interviews were conducted regarding farmers' beliefs about the consequences of SDCT. Audio recordings were professionally transcribed verbatim and analysed qualitatively using an inductive thematic analysis. The analysis identified 6 barriers and 6 facilitators to implementing SDCT. A significant fear of increasing mastitis incidence was evident that caused reluctance towards SDCT and reliance on antibiotics. Mixed perceptions on SDCT, infrastructure limitations, a perceived lack of preventive advice as well as peer influence were presented as barriers to SDCT. Farmers can build confidence when a graded approach to SDCT is implemented, which could help overcome the fear of SDCT and reliance on antibiotics. Regulatory pressure, high standards of farm hygiene and use of targeted veterinary consults were found to facilitate SDCT. Education was suggested to motivate farmers in the future uptake of SDCT. Despite cited negative influences, peer influence can be utilised to encourage the farming community. CONCLUSIONS: This study prioritises areas to facilitate the major behaviour change required as a dairy industry in order to move from blanket dry cow therapy to SDCT.