Cattle Practice October 2023

Cattle Practice OCTOBER 2023 Volume 31 Part 1

CONTENTS Thursday 19th October Calf management: The effect of single and paired housing on dairy calf health and welfare McFarland D Validating accelerometer technology to detect play behaviour in weaned dairy calves McKay C Neonatal calf enteric immunity: an update Gladden N Effect of neonatal immunoglobulin status on the outcomes of spring-born suckler calves Bragg R The epidemiology and control of gastrointestinal nematodes of first grazing season dairy calves in Scotland Campbell P ImmunIGy: A novel pen-side test for checking calf immune status Hayton A 10 months into pathway – where are we? Russell J The California Mastitis Test – Is there a value? Roberts J Identifying resilient cows, and quantifying the effect of in utero effects on lifetime performance Lewis K Automated disease detection using computer vision Hyde R Monitoring of efficacy of synchronisation programmes in a dairy herd using milk progesterone analysis Macrae A Practical experiences in using disease data to promote farmer and vet engagement in Johne’s Disease control – The development and impact of the Johne’s Tracker Hanks J Probabilistic predictions of Johne’s disease status through modelling of serial milk antibody ELISA results in combination with milk-recording data Glover I The use of economic replacement theory as a tool to support on-farm decision making Clifton R Demystifying cattle IVF for practitioners Simmons R 1 3 4 5 6 7 8 9 10 11 12 14 16 17 18 Can the type of microscope slide affect my assessment of semen motility during microscopy Nicholson H A comparison of oestrus synchronisation and fixed time AI followed by sweeper bulls to natural service breeding in 3 beef herds Penny C Participatory development of a National code of prescribing conduct and prescribing guidelines for farm vets in Wales Rees G Better understanding the associations between antimicrobial use and resistance through active surveillance of AMR on cattle and sheep farms across Wales Best C M From ‘knowing’ to ‘doing’ – Is veterinary medicine currently utilising the potential offered by the field of implementation science? Reyneke R Monitoring Flukicide Anthelmintic and Ecto-parasiticides (FAEcto) use in dairy farms in South West Scotland Watson E Benchmarking antimicrobial usage on UK Dairy Herds – Actionable insights from the last 5 years Rowland K What are the challenges faced by new graduates when making antibiotic prescribing decisions? Vallis R Encouraging antibiotic stewardship on smallholdings and amongst farm animals kept as pets Scott C Tools and tips to engage farmers with the control of infectious disease - case studies using Johne’s Disease as an example Orpin P Bovine reproductive manual and ultrasound examination May P Teaching and training skills for farm vets O’Malley P EMS – Better for you and better for the student Davies H Cattle Practice – What can poultry vets and calf vets learn from each other? Lock J 20 21 22 24 26 28 30 32 34 36 37 38 39 40

Friday 20th October Thoracic Ultrasound in Beef Suckler calves (BTUS) – Is it useful or even possible?! More J Farmer and Vet insights into the management of calf pneumonia – a place for rapid diagnostics? Potter T Dairy beef calves – integration to succeed but what really lies beneath? Bell D UK Beef Lameness; what we know, what we don’t know and where do we go? Tunstall J An assessment of KPI data for 50 suckler herds in the North West & Midlands of England Henderson A Sheep associated malignant catarrhal fever (SA-MCF): a series of cases on three farms in the UK Angell J W Collecting data on farm for surveillance and improved biosecurity King J “I know prevention is better than the cure, but...”: Barriers and facilitators to implementing on-farm measures to reduce the risk of bovine tuberculosis Collinson A A collaborative investigation of a new syndrome of gastroparesis in dairy heifers Swinson V Defining sustainability in the dairy sector Middleton M Approaches to reducing enteric methane emissions in dairy cows using a feed additive Walker N Sustainability for cattle practitioners: A review of recent literature Britten N The impact of youngstock health and systems on carbon footprint Dent H A survey of foot disinfection practices for control of bovine digital dermatitis; evaluating solution depth, footbath hygiene, and the potential of footbaths as infection reservoirs for Treponema species Gillespie A A new approach to lameness – introducing the Lameness Pattern Analysis Tool Manning A Association between a genetic index for digital dermatitis resistance and the frequency of infectious foot lesions in Holstein cows Anagnostopoulos A Foot anatomy and structure and its association with the development of claw horn disruption lesions in dairy cattle Griffiths B E Validation of a fully automated optical system for cattle lameness detection Siachos N Farm animal careers and perception of ‘fit’ in undergraduate veterinary students: A mixed methods study Payne E Veterinary student competence and confidence in calving cows after simulator training in a blended learning approach Orr J How WhatsApp client communication can save time, improve cash flow and reduce phone calls Samuel S How your website and digital platforms can help you with recruitment Aveston H “BVD diagnosis – that’s always straightforward! What could possibly go wrong?” McCormick I A Client’s calves have pneumonia again – why? Swinson V Using REMEDY to model dairy enterprise carbon footprints Can E Bridging the gap – thinking big picture to improve the effectiveness of your veterinary services Reyneke R Interpreting results from automatic lameness detection systems Randall L Getting started with Dynamic Health Planning in practice Geraghty T Saturday 21st October Can we predict the probability of a cow calving in with a high SCC? Thompson J Outcomes following cow caesareans: a clinical audit Robinson N 42 45 46 48 49 50 51 53 54 55 72 74 75 76 78 79 80 82 83 84 86 87 88 89 90 91 92 93 94 96

Serological prevalence of five common Bovine Respiratory Disease (BRD) pathogens in Great Britain Cresswell E Predictive modelling of deviation from expected milk Hannon F P Efficiently achieving 1000kg for sustainable dairy production maximising milk solids Jackson R Antimicrobial monitoring on UK dairy farms Potter T The effect of neonatal calf diarrhoea with and without dehydration and calf characteristics on saliva pH and conductivity Riley B The effect of neonatal calf diarrhoea with and without dehydration and calf level characteristics on blood parameters used to measure dehydration Riley B Health trends on UK dairy farms Rowland K How are fertility, production and health parameters changing in the national UK dairy herd? Trends in key performance indicators since 2010 Taylor E Antimicrobial resistance in Escherichia coli from UK cattle farms Wooding C J Other Papers Evaluation of the difference between mobility score outcomes conducted before and after milking: A study on 5 UK dairy farms Blowers B J Reduction in antibiotic use in 800+ GB herds supplying 11 processors from veterinary practice sales data and changes in farmer behaviour Matthews K Effect of GnRH injection at AI in winter housed dairy cows Penny C Mastitis surveillance - data sharing and collaborations Swinson V UK Beef Lameness; what we know, what we don’t know and where do we go? Floyd T When even the simplest things go wrong – food and drink disasters Murphy M A What can liver gene expression tell us about ketosis? Payling L Bovine Respiratory Coronavirus: an important contributor to the Bovine Respiratory Disease Complex Burr P Udder Cleft Dermatitis – a Practitioner’s eye view of the condition and approaches to treatment Kerby M Maintaining our reputation, export market and consumer confidence in burgers, chops and steaks Jelley M In practice calf castration antimicrobial use clinical audit Simms T Sustainable control of helminth parasites in cattle Williams D Why should we give a sh#t about dung beetles? Mann D Bovine Tuberculosis: how do we engage farmers? Sellick B Action plans to improve dairy herd health & welfare and reduce the need for antibiotic use: examples and discussion Breen J We need to talk about Red Cow Disease! Geraghty T BCVA Congress 2023 Posters Estimating prophylactic dry cow therapy use in GB dairy herds Blank A Evaluating the potential of untargeted lipidomic analysis of cow’s milk to predict lameness Cardoso A S Project FEET: Taking a whole team approach to recognising and treating lameness in dairy cows Craven E 97 98 99 101 103 105 106 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 135 136 137

BRITISH CATTLE VETERINARY ASSOCIATION BCVA President: Colin Mason Senior Vice President: Elizabeth Berry Junior Vice President: Bridget Taylor Hon. Secretary: Karen Bond and Sara Pedersen Hon. Treasurer: Kat Hart BVA Rep: Sally Wilson Board Function: To discuss and formulate BCVA policy on cattle matters; to determine BCVA development and direction to assist in providing service to BCVA members. About the BCVA The British Cattle Veterinary Association was established in 1967 and is the cattle specialist division of the British Veterinary Association. The association is involved with all aspects of cattle veterinary matters and is consulted by many organisations for informed opinion. BCVA has a function in providing science and policy to Government and stakeholders on a range of cattle matters, representing the views of members in the industry and supporting the role of the vet in all aspects related to cattle health and welfare. BCVA works with many different organisations, including representation on groups such as CHeCs, CHAWG, Red Tractor as well as a number of Defra working groups. BCVA arrange CPD courses for Veterinary Surgeons throughtout the year on various topics relating to cattle health. BCVA’s Annual Congress is a mixture of scientific and practical papers given by speakers from the UK and abroad and is held in October. Other courses cover such issues as Mastitis, Nutrition, Lameness, Fertility and training for recent graduates. BCVA’s Journal Cattle Practice now has a peer-reviewed section. Papers for this secion are invited from all members, especially those in practice. We are very happy to provide help and advice to those less familiar with the publication process. Guidelines for submitting a paper can be found on the BCVA website (www.bcva.org.uk/cattle-practice/submit-a-paper). BCVA’s website (www.bcva.org.uk) has both public and members pages. BCVA offers individual and practice membership. This includes: ‹ Accessible, relevant CPD – (Subsidised rates or free-of-charge). ‹ Cattle Practice – BCVA’s annual dedicated cattle journal including a peer-reviewed section – available digital or in print (dependant on membership class). ‹ Cattle Quarterly – introduced in the Summer of 2021, a seasonal periodical that will include CPD, case studies, interviews and features. ‹ Discounted rates for BCVA Congress. ‹ Webinar Archive – we automatically pre-register members for a free monthly webinar – plus, each webinar is added to our growing archive. ‹ CattleCast – our podcast series exploring a range of farm vets experiences; from clinical topics and headline news stories to lifestyle themes and research topics. ‹ Vital representation and input at national level. ‹ Opt-in for SMS alerts for important disease outbreaks. BCVA, Unit 17, The Glenmore Centre, Waterwells Business Park, Quedgeley, Glos, GL2 2AP Tel: 01452 725735, Fax: 01452 725780, Email: [email protected], Web: www.bcva.org.uk

Cattle Practice is the journal of the British Cattle Veterinary Association Editor James Adams Assistant Editors Alice Miller Bridget Taylor Office Publications Aimee Hyett All communications to ‘Cattle Practice’ should be addresssed to: The Editor 17 The Glenmore Centre Waterwells Business Park Quedgeley Gloucestershire GL2 2AP Tel: 01452 725735 Fax: 01452 725780 Email: [email protected] Web: www.bcva.org.uk Material published in Cattle Practice reflects the views of the author, not necessarily those of Cattle Practice or BCVA. All papers are reproduced by permission of the authors or their original source (acknowledged with the paper). The material contained in this journal is only available for reproduction by other cattle journals for education purposes. Any other publication requires the prior permission of the Editor and the author. ISSN 0969-1251 We may have clients who are still intent on getting another cut of silage in, but that doesn’t mean that Autumn is not upon us. For BCVA and all of it’s members, the shorter days signify that Congress is near, which this year is to be held in Telford from the 19th – 21st October. This is not only your annual opportunity to catch-up with university peers and past work-colleagues, but it provides ample opportunity for you to explore all manner of things that come under the term ‘Role of Farm Veterinarian’, some of which you may be unaware of, or maybe dismissed as irrelevant at times. With the 2023 programme we have tried to titivate and indulge both new graduates and those who might be wearing spectacles to Congress for the first time (and those who can’t remember where they left said specs). We are very keen to make sure that all feel catered for, hence we have spread the net wide when looking for speakers on topics that you may consider well-trodden as we all like to hear a different opinion. Have you ever met a vet who doesn’t have an opinion?! We greatly appreciate all of those who have taken the time and effort to speak at Congress or present a poster. Please take your time to listen and learn from these people, and maybe thank them at some point for without them Congress would not exist. The same goes for this journal. If you feel able to contribute than please get in touch on [email protected]. See you in Telford. James Adams Editor EDITORIAL

CATTLE PRACTICE VOLUME 31 PART 1 2023 1 Calf management: The effect of single and paired housing on dairy calf health and welfare Mcfarland, D., Farm Animal Practice, Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, EH25 9RG ABSTRACT There have been a number of welfare concerns raised about the individual rearing of dairy calves in early life, such that the practice is now not allowed for many UK dairy farmers under a number of supermarketaligned contracts. Using a non-randomised control trial, this project examined the effects of individual versus pair-rearing of dairy calves on calf productivity (assessed via daily liveweight gain), health (morbidity and mortality) and welfare assessments (assessed using a number of behavioural measures including latency to feed and latency to approach a novel object test, as well as salivary cortisol measurements). The hypothesis was that pair-rearing dairy heifer calves from birth to 2-3 weeks of age compared to individual rearing will provide long-term benefits in calf performance, health and welfare. In the published literature in this area to date, few papers have included a large number of calves in their studies. Most papers average between 20-40 calves (Jensen and others 1997, Chua and others 2002, De Paula Vieira and others 2010, Costa and others 2015, Bolt and others 2017) with the highest number of calves being 110 (Jensen and Larsen 2014) although these calves were split into 5 groups. A common theme in the papers reviewed was to test calves around 6-16 weeks of age (De Paula Vieira and others 2010, Jensen and Larsen 2014, Knauer and others 2021). Relatively few studies investigated the effect of pairing calves at 2-3 weeks of age, as is common on dairy farms within Scotland to group calves at this stage for ease of management. There is currently also a lack of research published focussing on the effect of paired calves around new environments (i.e. batching) at 2-3 weeks of age. The use of cortisol salivary biomarkers has been shown in studies to be an indicator of stress and may assist in the detection of potential welfare issues in current farming practice (Contreras-Aguilar and others 2019). The project was based on a 450 cow Holstein Friesian dairy herd (predominantly autumn calving), and recruited 131 heifer calves onto the trial. Calves were allocated at birth to being either A) penned individually and B) as pairs from birth. Dairy heifer calves were penned in the order that they calved, to allow calves of similar age to be paired together. The experimental unit was the pen, and the study design required the same number of individual pens to paired pens (for example 5 individual pens (5 calves) to 5 paired pens (10 calves)). At 2-3 weeks of age, calves were transported as per standard farm management practice to go onto batch pens. The calves were then group housed in batches of 12 calves, whilst continuing on milk feeding. At approximately two months of age, the calves were weaned. Calf weights were recorded at birth, at batching and at weaning, allowing the calculation of average daily liveweight gain (ADLWG). All calf treatments and reason for treatment were recorded, as well as calf mortality. For behavioural assessment, all calves were given a unique identifiable mark using a combination of 4 different coloured marker sprays. This provided two purposes, in that it allowed calves to be identified on the video recordings and secondly it helped remove bias from the study. In the Latency to Feed test, video footage was recorded at two timepoints: A) first feed after batching and B) second feed after batching 24 hours later. This was subsequently analysed to determine how quickly the calves came forward for food. In the Latency to Approach a novel object test, a coloured gym ball was placed in the middle of the pen, and video footage was taken to assess the approach of calves within the following 15 minutes. Saliva samples were collected from calves using a Salivette Cortisol swab to collect approximately 1ml of saliva. Saliva samples were taken at three timepoints around batching: Prior to batching, 45 minutes after batching, and 24 hours after batching. The samples were frozen at -20°C until subsequent analyses by SRUC Biomarkers laboratory for salivary cortisol. The study found that the ADLWG from birth to weaning for individual and paired calves to be 0.63kg and 0.64kg respectively. One individual calf and two paired calves required veterinary intervention for the treatment of diarrhoea. 24% of individual calves and 12% of paired calves required treatment for pneumonia. The median for latency to feed at the first and second feed after batching was 3 and 0 seconds for paired calves, and 9 and 6 seconds for single calves respectively.

CATTLE PRACTICE VOLUME 31 PART 1 2023 2 Further analysis will be presented once the saliva cortisol analyses and behavioural data has been completed. Preliminary data suggests that there is no significant difference in ADLWG, although there may be potential differences in behavioural data worth further investigation. ACKNOWLEDGEMENTS This project was part-funded by the Hannah Dairy Research Foundation. REFERENCES Bolt, S.L., Boyland, N.K., Mlynski, D.T., James, R., Croft, D.P. (2017) Pair Housing of Dairy Calves and Age at Pairing: Effects on Weaning Stress, Health, Production and Social Networks. PLOS ONE 12(1): p.e0166926. Chua, B., Coenen, E., van Delen, J., Weary, D. (2002) Effects of Pair versus Individual Housing on the Behavior and Performance of Dairy Calves. Journal of Dairy Science 85(2): pp.360-364 Contreras-Aguilar, M., Monkeviciene, I., Ceron, J., Silinskas, I., Vallejo-Mateo, P., Tecles, F., Martinez-Subiela, S., Tvarijonaviciute, A., Zelvyte, R. (2019) Biochemical changes in saliva of cows with inflammation: A pilot study. Research in Veterinary Science 124: 383-386 Costa, J., Meagher, R., von Keyserlingk, M., Weary, D. (2015) Early pair housing increases solid feed intake and weight gains in dairy calves. Journal of Dairy Science 98(9): 6381-6386 De Paula Vieira, A., von Keyserlingk, M.A.G., Weary, D.M. (2010) Effects of pair versus single housing on performance and behavior of dairy calves before and after weaning from milk. Journal of Dairy Science 93(7): 3079–3085 Fujiwara M., Haskell M.J., Macrae A.I., Rutherford, K.M.D. (2020) Impact of Maternal High Stocking Density during the Dry Period on Dairy Calf Health, Behaviour, and Welfare. Animals (Basel) 10(6): 922 Jensen, M., Vestergaard, K., Krohn, C., Munksgaard, L. (1997) Effect of single versus group housing and space allowance on responses of calves during open-field tests. Applied Animal Behaviour Science 54(2-3): 109-121 Jensen, M., Larsen, L. (2014) Effects of level of social contact on dairy calf behavior and health. Journal of Dairy Science 97(8): 5035-5044 Knauer, W., Godden, S., Rendahl, A., Endres, M., Crooker, B. (2021) The effect of individual versus pair housing of dairy heifer calves during the preweaning period on measures of health, performance, and behavior up to 16 weeks of age. Journal of Dairy Science 104(3): 3495-3507

CATTLE PRACTICE VOLUME 31 PART 1 2023 3 Validating accelerometer technology to detect play behaviour in weaned dairy calves McKay, C.1 , Haskell, M.J.2 , Ellis, K.1 , Gladden, N.3 , 1 Scottish Centre for Production Animal Health and Food Safety, University of Glasgow School of Biodiversity, One Health and Veterinary Medicine, Glasgow, G61 1QH 2 Scotland’s Rural College (SRUC), West Mains Road, Edinburgh, EH9 3JG 3 School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, Loughborough, LE12 5RD OBJECTIVES Animal welfare is an increasingly important subject that is gaining interest not only from veterinarians and scientists, but also from consumers. The public drive for higher welfare standards has increased the need for research to better understand the needs and nature of animals. Play behaviour is commonly observed in young animals and may be adversely affected by negative experiences. Thus, play can be regarded as an indication of a positive welfare state. Observational methods of recording animal behaviour can be labour intensive and impractical for studies of long duration. The increase in commercially available accelerometer technology has allowed for detailed analysis of animal behaviours in a more efficient manner than continuous visual observations. Accelerometers have been validated for detecting play behaviour in newborn (≤ 48h old) dairy calves but not in any other age group of cattle. The objective of this study was to determine the ability of accelerometers to detect play behaviour in older calves (3 to 5 months old), with a particular focus on motion index (MI) – a proprietary measure of overall animal activity (IceTag, Peacock Technology, Scotland). MATERIALS AND METHODS Eight weaned female Holstein-Friesian calves (age 118 ± 16 d) were recruited from a 50-cow dairy herd in central Scotland. Calves were housed in a strawbedded group pen of up to ten calves and had ad libitum access to water, concentrate pellets and straw. Accelerometers (IceTag, Peacock Technology) were attached to one hindlimb of each calf for a 48-hour period. Sensor data were downloaded in 15-min intervals at the end of the recording period. These devices measure acceleration forces which occur during animal movements and output a variety of activity data including step count, lying times and a measure of overall activity termed “motion index (MI)”. Calf behaviour was filmed continuously over the same 48-hour period using two cameras providing an unobstructed view of the calf shed. Behavioural analysis was conducted using one-zero sampling to identify the presence (1) or absence (0) of play within each 15-min interval corresponding to the IceTag data output. Visual observations and MI data were compared and formatted in 2x2 contingency tables for the calculation of the sensitivity (Se), specificity (Sp) and balanced accuracy of different MI thresholds to detect the presence of play. RESULTS The number of 15-min intervals in which play events were recorded varied between calves and ranged from 9 to 39 (median 26) over the 48-hour recording period. The median MI was 6 (range 0 to 2343). The MI threshold which best correlated with visual identification of play behaviour was MI ≥ 69 (sensitivity = 94.42%; specificity = 93.60%; balanced accuracy = 94.01%). CONCLUSIONS The results of this study suggest that IceTag generated MI data can be used as a more time efficient alternative to visual analysis to detect play behaviour in weaned dairy calves. This technology can be implemented as a research tool in comparing play, an indicator of positive welfare states, in weaned dairy calves across different management systems.

CATTLE PRACTICE VOLUME 31 PART 1 2023 4 Neonatal calf enteric immunity: an update Gladden, N., Room A04 , Gateway Building, University of Nottingham School of Veterinary Sciences, Sutton Bonington Campus, Sutton Bonington, Leicestershire, LE12 5RD Neonatal enteritis (also known as neonatal calf diarrhoea) is one of the most common diseases diagnosed in young calves, with a reported prevalence of approximately 20%. Globally, neonatal enteritis is the most common cause of morbidity and mortality of calves under one month of age and as such is an important contributor to reduced calf welfare. Additionally, costs associated with neonatal enteritis (such as treatment costs, calf losses, and reduced subsequent performance) can be significant. The most common pathogens isolated from affected calves are E.coli, rotavirus, coronavirus, and Cryptosporidium parvum but these pathogens can also be isolated from the faeces of healthy calves, suggesting that other factors are also contributing to neonatal enteritis and the presence of these enteric pathogens may not always be the cause of diarrhoea. As such, neonatal enteritis is a complex condition that can be challenging for both veterinary surgeons and farmers. Neonatal immunity is an important consideration in the management of neonatal enteritis and the importance of colostrum management for neonatal ruminants is well documented. It is well established that calves with failure of passive transfer are at increased risk of neonatal enteritis, as well as other diseases. Furthermore, colostrum has an important role in neonatal intestinal development and colostrum quality has been found to be positively associated with development of intestinal immunity. Therefore, optimisation of colostrum management is a critical component in approaches to reducing the incidence of neonatal enteritis on farms. Mucosal immunity is an essential part of the immune system and has been subject to much research in recent years. In healthy intestines, the normal gut flora (microbiota) contributes to local immunity in three ways: 1. Competition for binding sites and nutrients. 2. Promotion of expression of mucous, antimicrobial peptides, and IgA to form a layer termed the ‘kill zone’. 3. Enhancement of immune responses to pathogens. Accordingly, maintenance of a healthy intestinal environment (in particular the gut flora) has an important role in enteric immunity of neonatal calves and aids the immune defence in the face of exposure to enteric pathogens. A number of approaches to optimise calf intestinal immunity have been described, including vaccination, feed supplements such as pro- and pre-biotics, and passive immunity. Vaccination is commonly performed indirectly by vaccinating the cow so that the colostrum contains antibodies to selected pathogens. Vaccination of calves directly is typically less effective due to the early exposure of calves to enteric pathogens, and the time taken to mount an immune response. Pre-biotics and pro-biotics have been found to augment intestinal immunity by enhancing mucosal tight junctions and optimising mucosal immunity respectively. As such, there is increasing interest in the use of these compounds for maintenance of intestinal health in young calves, but further research is needed to fully understand their effects. Passive immunity is an approach where an agent producing an immune response (e.g. antibodies) is administered to provide support to the calf’s immune system and has been successfully utilised in the management of E.coli diarrhoea in calves. Passive immunity has also been associated with reduced incidence of neonatal enteritis, even in calves with adequate passive transfer, and it is hypothesised that these products enhance the local mucosal immunity of the intestinal tract (in particular providing support to the ‘kill zone’) and augment colostral immunity. Neonatal calf enteritis is a complex condition that can be challenging to manage. Optimising calf immunity by ensuring adequate passive transfer of immunoglobulins is a key factor in the management of neonatal calf enteritis, but there is increasing awareness of the importance of the role of enteric mucosal immune defences to pathogens. Providing support to, and enhancement of, the intestinal microbiota and mucosal immune defences therefore has potential to further improve calf health and aid management of neonatal calf enteritis, a condition with important welfare and economic implications. This lecture aims to provide a review and update of the recent literature regarding calf immunity with a focus on intestinal immune defences and the implications for management of neonatal enteritis.

CATTLE PRACTICE VOLUME 31 PART 1 2023 5 Effect of neonatal immunoglobulin status on the outcomes of spring-born suckler calves Bragg, R., Corbishley, A., Lycett, S., Burrough, E., Russell, G., Macrae, S., The University of Edinburgh, Easter Bush Campus, Bush Farm, Roslin, Midlothian, EH25 9RG BACKGROUND Successfully rearing beef calves to weaning and beyond determines the economic performance of a beef farm. As such, it is important to understand the factors influencing performance outcomes. METHODS This study recorded the health events, mortality and growth rates of 674 calves born on 50 commercial beef farms in Great Britain using a postsampling questionnaire. All calves had a known postcolostral serum IgG status. RESULTS Preweaning mortality in the study population was 1.5% (10/674 calves), while the treatment rate was 6.4% (43/674 calves). Serum IgG, calf sex and dystocia were significant predictors of whether a calf died and/or required treatment. Average daily liveweight gain was calculated for calves where weaning weights were provided (n=513). Serum IgG and calf sex were consistent predictors of calf growth rates, while birthweight and whether the calf was born to a cow or heifer were predictive in a model where average daily liveweight gain was converted to a binary response variable using the mean average daily liveweight gain on the calf’s farm of origin. LIMITATIONS Morbidity and mortality were lower than comparable studies, potentially due to limitations in the study design. CONCLUSION Serum IgG and calf sex were significant explanatory variables that affected beef calf average daily liveweight gain. For every 5g/L increase in serum IgG, the odds ratio of dying and/or requiring treatment decreased by 0.86.

CATTLE PRACTICE VOLUME 31 PART 1 2023 6 The epidemiology and control of gastrointestinal nematodes of first grazing season dairy calves in Scotland Campbell, P., University of Glasgow, 464 Bearsden Rd, Glasgow, G61 1QH Gastrointestinal nematode (GIN) epidemiology may be changing spatially and/or temporally in regions worldwide. Climate change, the advancement of livestock management strategies, and the emergence of anthelmintic resistance are suspected to be the main driving factors of such changes. Helminth parasites have been shown to be strongly influenced by short-term weather and the climate through their effects on the free-living larval stages. Hence, there is a need for data describing how these epidemiological dynamics and, therefore, parasitic challenges to livestock may have changed; in order to provide veterinarians and farmers with relevant, informed advice on parasite control and best practices. The dynamics of these changes on Scottish dairy farms are currently poorly understood; due to the lack of empirical data using modern-molecular techniques. This longitudinal study aimed to monitor and estimate the specific species prevalence and faecal egg count intensities of GIN in first-grazing season (FGS) dairy calves in Scotland. Twenty commercial dairy farms in mainland Scotland were recruited in 2022 and followed for one full grazing season. Fresh environmental faecal samples (n=1498) were collected at monthly intervals (May to October). Within each group comprising a minimum of 30 individuals, 15 random faecal samples were collected. Sampling was conducted in and around each farm’s anthelmintic treatment regime, and the study did not stipulate any specific form of treatment. Eggs per gram of faeces (EPG) were determined using a modified McMaster technique, with a sensitivity of 8 EPG. The predominant gastrointestinal nematode species at the group level were identified by a multiplex PCR-based method. The assay targets unique species-specific markers of the second internal transcribed spacer (ITS-2) region of rDNA of L3-stage nematodes utilising individual larval lysates. Of the 20 farms recruited, four were organic, and 16 were conventional commercial holdings situated in either South-west Scotland, the Central belt or Aberdeenshire. Each participating farm was surveyed on general livestock and pasture management, anthelmintic usage, and key performance indicators. As expected, the majority of farms treated FGS calves using a macrocyclic lactone class product (n=14), with one treating with a benzimidazole product and five farms applying no anthelmintic products before housing. The number of treatments given before housing ranged from 0 to 4, with a median of two applications. All treatments were blanket treatment, with every individual in the cohort receiving treatment. The turnout dates for the FGS calves ranged from 23/03/22 to 16/06/22, and housing dates ranged from 19/10/22 to 07/11/22, with two farms overwintering calves outside. The faecal egg count intensity in the FGS calves remained relatively low throughout the study period. Individual FGS calf egg counts ranged from 0 to 456 EPG; no cohorts exhibited any clinical signs of parasitic gastroenteritis. But one cohort did experience an outbreak of lungworm, showing early clinical signs, and was treated accordingly. Unlike that of Ostertagia ostertagi milk antibody levels, there is currently no indicative FEC threshold at which a production-limiting impact is known. Faecal egg counts are often poorly correlated to an individual’s adult worm burden or the risk of clinical parasitic gastroenteritis, with FEC often low in cases of PGE. While the coinfection of cattle with GIN is complex, not all risk factors could be integrated into the study. This study, however, assesses previously unavailable data on the epidemiology of GIN in FGS calves in Scotland by evaluating the minimum species prevalence and FEC intensity. PRACTICAL TAKE HOME MESSAGES Changing climate, the advancement of livestock management strategies and anthelmintic resistance have a strong influence on gastrointestinal nematode parasitism in the field. And hence, there is a need to understand the current epidemiological dynamics. There is a lack of robust evidence of a consistent correlation between FECs and adult GIN burdens, or the impact of parasitism on the host. Effective parasite control requires the active engagement by both farm vets and their clients, so that collectively their knowledge can be utilised to monitor the impacts of GIN parasitism and implement effective interventions that will optimise both animal health and performance.

CATTLE PRACTICE VOLUME 31 PART 1 2023 7 ImmunIGy: A novel pen-side test for checking calf immune status Hayton, A., Synergy Farm Health Ltd, The Transmission Hall, Rampisham Business Centre, Rampisham Down, Maiden Newton, Dorset, DT2 0HS Serum concentration of IgG in neonatal calves is a direct marker of the level of passive transfer of maternal antibody from colostrum. There is substantial evidence that successful passive transfer is associated with decreased morbidity and mortality rates, improved growth rates and lifetime productive capacity, whether the calf is destined to produce milk or enter the beef supply chain. As such, successful passive transfer is a key driver of economic and environmental efficiency on both dairy and beef farms rearing calves sourced from dairy units. A review of failure of passive transfer (FPT) published in 2021 showed a prevalence range in dairy herds in the USA and Europe between 12 and 43% and the authors of the study concluded that due to the production, health, and economic impacts of FPT and its high prevalence in several countries, that this problem should be seriously addressed worldwide (Soalheiro de Souza and others 2021). Monitoring for FPT is accepted good practice. However, as testing usually requires a vet to obtain the blood sample and a laboratory to carry out the test, monitoring for FPT is currently under-performed. The potential value of monitoring FPT using IgG is not just within the first week of life but also within beef rearing units when calves are a few weeks of age. There is an increasing trend for beef calves to originate from dairy herds (50% of UK beef is now produced from this source and this percentage is expected to increase (AHDB)). The usual method for rearing such calves is for their collection from dairy herds and their subsequent dissemination to specialised rearing units where they remain until around 5 months of age. Such rearing systems present significant health challenges, as calves being mixed from multiple sources almost inevitably means their exposure to multiple pathogens, and, especially if the calves are immunecompromised via a FPT, there is high risk of disease outbreaks. Showing the value of such testing on entry to the rearing unit would prove transformational in optimising the quality of animals purchased, through information feedback and differential pricing, and improving outcomes and reducing antibiotic use through group appropriate management practices. ImmunIGy is a novel Point of Care Lateral Flow Device (LFD) test to be used in conjunction with a Cube Reader, enabling quantitative determination of IgG levels in whole blood. Results are available in a few minutes. The blood sample for testing is acquired via a novel lancet applied to an insensitive part of the calf’s nose. This system of obtaining blood has not been used previously in cattle and allows unskilled operators to obtain the sample. This combination of the test and the sample collection system allows the potential for farms to conduct their own routine monitoring of FPT. The presentation will demonstrate the test process methodology and research outcomes of an external independent validation of the test to confirm that ImmunIGy test results correlate with the current gold standard for IgG (results not yet produced at time of writing). REFERENCES Soalheiro de Souza, R., Costa dos Santos, L.B, Melo, I.O., Cerqueira, D.M., Dumas, J.V., Leme, F.P., Moreira, T.F., Meneses, R.M., Ultimo de Carvalho, A., Facury-Filho, E.J. (2021) Current Diagnostic Methods for Assessing Transfer of Passive Immunity in Calves and Possible Improvements: A Literature Review. Animals 11(10): 2963

CATTLE PRACTICE VOLUME 31 PART 1 2023 8 10 months into pathway – where are we? Russell, J.1 , Statham, J.M.E.2 , 1 University of Nottingham, Room A04 Gateway, Sutton Bonnington, Leicestershire, LE12 5RD 2 Bishopton Veterinary Group, Mill Farm, Studley Road, Ripon, Yorkshire, HG4 2QR This session, co-hosted by Jonathan Statham (Chair, Animal Health and Welfare Board for England) and James Russell (NED, AHWBE) will explore the decisions around co-design taken over a period of years to develop the current vet visit aspect of the animal health and welfare pathway. There will be opportunity to understand how the pathway visit fits alongside the health and welfare grants, and how you might maximise the opportunities presented by the pathway to enhance endemic disease surveillance for all farms, especially those who do not have a history of such engagement. Veterinary involvement in this aspect of the future delivery of endemic disease control on farms will be crucial, and should provide opportunities to support farmers further in coming years. With a move away from Single Farm Payment already underway, the pathway and its outputs will play an increasingly important role in delivering public money for public good in English agriculture. We will briefly summarise what is similar, and what is different across the 4 nations of the United Kingdom, before inviting attendees to question Jonathan and James about the role of AHWBE in developing and delivering on health and welfare priorities in England.

CATTLE PRACTICE VOLUME 31 PART 1 2023 9 The California Mastitis Test – Is there a value? Roberts, J., Map of Ag, Unit 15, Deben Mill Business Centre, Old Maltings Approach, Melton, Woodbridge, IP12 1BL The California Mastitis Test (CMT) is widely used as a qualitative cow side test for the detection of subclinical mastitis in dairy cattle (Middleton and others 2004). The threshold for this test is quoted as being between 200,000 and 400,000 cells/ ml based on human observations of the reaction rather than scientific measurement of the gel that is formed. The viscosity of the milk-CMT gel reaction has been characterised (Whyte and others 2005) but at present no successful attempt published determining whether the reaction can assess quantitatively the somatic cell count (SCC) in milk samples and the threshold at which the gel reaction occurs. The objective of this research was to fully characterise the CMT reaction at various SCC’s, to establish the threshold of the reaction and the quantitative relationship between the CMT reaction and SCC in milk. Foremilk samples were collected from 35 quarters from 21 Holstein-Friesian cows on a commercial dairy herd in the UK. Viscosity measurements were made using a Brookfield DV-II+ Viscometer (Brookfield, UK) at constant shear rate of 30rpm at 25○ C for 3.5ml milk with 3.5ml CMT reagent. A proportion of each quarter milk sample was sent away for external SCC measurement at a commercial approved laboratory (QMMS Limited, UK). The CMT reaction has a defined viscosity curve for each sample and there is a good correlation between SCC and μmax when samples are compared. The threshold at which the gel reaction occurs for the CMT can be clearly demonstrated by plotting log SCC against 1/e tμmax, with the threshold being approximately 390,000 cells/ml. THE CALIFORNIA MASTITIS TEST – PRACTICAL APPLICATION With knowledge of the threshold value of the CMT, the CMT can be considered for the following uses: • Identification of the infected quarter e.g. high SCC cow. • Confirmation of mastitis in a toxic cow. • Monitoring of response to treatment. • New calved cow mastitis identification. • Selective dry cow therapy decision making. REFERENCES Middleton, J.R., Hardin, D., Steevens, B., Randle, R., Tyler, J.W. (2004) Use of somatic cell counts and California mastitis test results from individual quarter milk samples to detect subclinical intramammary infection in dairy cattle from a herd with a high bulk tank somatic cell count. JAVMA 224(3): 419-423 Whyte, D., Walmsley, M., Liew, A., Claycomb, R., Mein, G. (2005) Chemical and rheological aspects of the gel formation in the California Mastitis Test. Journal of Dairy Research 72: 115-121

CATTLE PRACTICE VOLUME 31 PART 1 2023 10 Identifying resilient cows, and quantifying the effect of in utero effects on lifetime performance Lewis, K.1 , Bradley, A.2 , Carter, L.S.3 , Dewhurst, R.3 , Forde, N.4 , Hyde, R.1 , Kaler, J.1 , Mason, C.3 , Strain, S.5 , Thompson, J.1 , Green, M.1 , 1 University of Nottingham, Stanford, Sutton Bonington, Loughborough, LE12 5RD 2 Quality Milk Management Services, Cedar Barn, Easton Hill, Easton, Wells, Somerset, BA5 1DU 3 Scotland’s Rural College, Craibstone Estate, Ferguson Building, Aberdeen, AB21 9YA 4 University of Leeds, Worsley Building, University of Leeds, Woodhouse, Leeds, LS2 9JT 5 Animal Health and Welfare Northern Ireland, Unit 49, Dungannon Enterprise Centre, 2 Coalisland Rd, Dungannon, Co. Tyrone, BT71 6JT Resilient cows are generally thought to be those that have good reproductive performance, high milk yields and a long productive life span, with few health problems, which if they occur, are easily resolved. Resilience can be measured using cow-level data using a lifetime resilience score (Adriaens and others 2020), where cows are allocated “points” based primarily on the number of calves they have and their reproductive performance relative to the rest of the herd. There is increasing evidence that the in utero environment experienced by a calf contributes to their future lifetime performance and resilience. Examples of events that can cause changes in the in-utero environment, altering conceptus development and programming are disease insults and heat stress, which causes changes in placental mass and vasculature structure. The aim of our research was to examine the effect of potential “stressors” that the calf experienced while in utero on lifetime performance, as measured by the score from Adraeins and others (2020). Herd records were retrieved from 108 farms (Total Vet/QMMS). Following data cleaning, 84,304 cows were selected that were born from 01/01/2006 to 31/12/2015, and 35,891 mother-daughter pairs identified. Selected health “stressors” were cases of mastitis, lameness (including those identified in a mobility score) and instances of use of anti-microbial and anti-inflammatory medicines during the pregnancy. Potential thermal discomfort effects were determined using data from the National Centres for Environmental Information (National Oceanic and Atmospheric Administration) to calculate a daily thermal-discomfort index based on the maximum temperature observed per day (Thom 1959) (THI). Data were summarised for each calf into 1) maximum THI experienced while in utero, and 2) the number of potential heat stress days experienced, using a threshold of THI ≥ 68. Preliminary results from linear mixed effects models suggest that having a healthbased stressor in utero may be associated with changes in lifetime resilience score, further work will explore this association, as high yielding cows are known to be more susceptible to health problems. Brief take home message relevant to practitioners It is increasingly recognised that sustainability is key to the dairy industry and an element of this is to enhance the resilience, efficiency and lifetime productivity of dairy cows. This research is identifying long lasting effects of the in utero environment, which could help farmer and vet decision making and therefore improve herd health and sustainability. REFERENCES Adriaens, I., Friggens, N.C., Ouweltjes, W., Scott, H., Aernouts, B., Statham, J. (2020) Productive life span and resilience rank can be predicted from on-farm first-parity sensor time series but not using a common equation across farms. Journal of Dairy Science 103(8): 7155–7171. https:// doi.org/doi.org/10.3168/jds.2010-3483 Thom, E.C. (1959) The discomfort index. Weatherwise 12(2): 57–61. https://doi.org/https://doi.org/10.1080/00431672.19 59.9926960

CATTLE PRACTICE VOLUME 31 PART 1 2023 11 Automated disease detection using computer vision Hyde, R., University of Nottingham, C17 Gateway Building, Sutton Bonington Campus, School of Veterinary Medicine and Science, University of Nottingham, LE12 5RD The British cattle industry is faced with a wide range of diseases that has a negative impact animal health and welfare, substantially reduce productivity and are responsible for significant financial losses. As farm animal veterinary surgeons, we know that the rapid, and accurate identification of disease is critical for both prompt treatment of individual animals and the ability to benchmark key health and welfare outcomes between farms. However, currently, disease identification on cattle farms generally relies on the subjective, visual observation from an often time-poor farmer, which results in significant underdiagnosis, and is often relatively inaccurate. The latest developments in artificial intelligence (AI) research will provide a step change in this conventional approach, and the use of computer vision to automatically identify disease in animals is already becoming a reality on many cattle farms across the country. The use of computer algorithms linked to camera systems to constantly, and objectively monitor animal health would represent a paradigm shift in how we operate as farm animal veterinary surgeons, represents an enormous opportunity for cattle vets to improve animal health and welfare of farm animals at a national level. The automatic detection of health and welfare issues will enable faster treatments, as well as allowing a more data-driven epidemiological investigation of disease by veterinary surgeons. Alongside improvements for animal health, there would be significant benefits to wider society, and limiting the effects of disease through computer vision diagnosis would decrease both antimicrobial usage as well as the environmental impact of food production. Recent research conducted at the University of Nottingham School of Veterinary Medicine and Science over the last year has resulted in the development of several machine vision algorithms able to automatically monitor key animal health and welfare outcomes accurately, and without human intervention. There are several commercial examples of computer vision algorithms being used to improve cattle health and production today, and the farm vet of the future will play a key role in translating this technology into practical improvements on farms for many more to come. This presentation will provide the practical farm animal veterinary surgeon with an understanding of what computer vision can achieve in the automated diagnosis of disease and demonstrate through videos of animal disease what can be achieved with computer vision algorithms. The talk will provide listeners with the tools they require to utilise computer vision technology to automatically detect disease on their farms, and crucially, the ability to interpret the results provided by this technology to drive practical improvements in animal health outcomes.

CATTLE PRACTICE VOLUME 31 PART 1 2023 12 Monitoring of efficacy of synchronisation programmes in a dairy herd using milk progesterone analysis Macrae, A., DHHPS, RDSVS, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian, EH25 9RG Synchronisation programmes with subsequent fixed time artificial insemination (AI) are used predominantly in dairy herds to improve submission rates in the face of poor heat detection. Most studies show improvements in the number of pregnant cows following such synchronisation programmes, with cost:benefits for overall dairy herd profitability due to increased numbers of freshly calved cows, and overall improvements in national dairy herd fertility (Fricke and Wiltbank 2022). However such synchronisation protocols are complex, with a number of fertility drugs needing to be administered at correct times and in sequence, with fixed time AI at the correct time. There are also a wide range of differing programmes available, depending on the age and reproductive status of the cow at enrolment (DeJornette 2015). This complexity can result in potential compliance issues that can reduce the efficacy of such synchronisation protocols, resulting in perceived failure to generate sufficient numbers of pregnant cows. This apparent failure can be the result of not following the correct protocols, but may also be due to incorrect enrolment of cows at the correct stage of the oestrus cycle, or ovarian pathology (such as cystic ovarian disease). In addition, there may be many other factors affecting apparent conception rates such as poor semen handling or AI technique (Cook 2009). Assessment of synchronisation protocols is therefore necessary as part of any investigation into poor conception or pregnancy rates in a dairy herd. This paper describes the use of milk progesterone sampling to investigate issues with synchronisation programmes in a dairy herd, as part of a wider investigation into poor conception rates. An investigation was requested as the overall all services conception rate (CR) for the last 12 months had fallen to 21.5%. Although initial investigations were focused on suspected nutritional causes, it was found that conception rates were poor at all stages, including by Days in Milk, service number and lactation number, and had remained poor for at least 12 months. It was therefore considered that a nutritional cause was unlikely, which was confirmed by good cow body condition, herd milk butterfat and protein levels, and a metabolic profile which revealed no significant current nutritional concerns in the herd. Three members of farm staff were involved in AI, and there was no significant difference in CR between the different inseminators who were using the farm semen store. Of the 2181 inseminations performed in the previous 12 months, 1,220 (56%) were undertaken after heat was detected by an activity detection system with a CR of 25.1%, 72 (3%) were undertaken to cows in standing heat (26.6%), 716 (33%) were undertaken using synchronisation protocols (CR 14.2%) and 173 (8%) were “unknown”. Investigations were undertaken into the farm semen store (which was found to be faulty 6 months previously) and semen thawing. However in light of the lower CR using synchronisation protocols, it was decided to investigate this further using milk progesterone analysis on the day of service. Milk samples were collected from cows on the day of AI by manual stripping of one quarter into a milk sampling pot with bronopol preservative tablet, after discarding the first 4-5 squirts of milk. The samples were then sent to Ridgeway Science for analysis of progesterone levels (P4) using an ELISA. P4 values below 1.5ng/l were considered low, 1.5-3ng/l as medium, and P4 values over 3ng/l were considered high. Initial sampling of 11 cows on the day of service following various synchronisation protocols and fixed-time AI (mix of Ovsynch and CIDR-synch) showed that no cows had low P4 results, 7 had medium milk P4 results, and 5 cows had high milk P4 on the day of service. Only one of these 11 services resulted in a conception. Following discussion of the synchronisation protocols and simplification, a second round of sampling 17 cows (2 of which were served on standing heat, 15 following synchronisation protocols) showed that 6 cows had low P4 results, 9 had medium milk P4 results, and 2 cows had high milk P4 on the day of service. Only two of these 17 services resulted in a conception. A third round of sampling 17 cows (all following synchronisation protocols) showed that 7 cows had low P4 results, 6 had medium milk P4 results, and 4 cows had high milk P4 on the day of service.

CATTLE PRACTICE VOLUME 31 PART 1 2023 13 It was considered that a number of factors were likely to be involved in the poor CR in this herd, but that lack of efficacy of the synchronisation protocols was likely to be a contributory factor (Omontese and others 2020). A number of issues identified included poor compliance with the programmes, and a plan was put in place to simplify and standardise the synchronisation protocols used to improve compliance. REFERENCES Cook, J. (2009) Understanding conception rates in dairy herds. In Practice 31: 262-266 DeJornette, M. (2015) Ovsynch, Co-Synch, Presynch and Kitchensynch: how did breeding cows get so complicated? http://www.infodairy.com/infodairy_upload_files/ Cows_heifers_calves/Reproduction/0301ovsynch_cosynch_ presynch.pdf Accessed 9th February 2023. Fricke, P.M., Wiltbank, M.C. (2022) Symposium review: The implications of spontaneous versus synchronized ovulations on the reproductive performance of lactating dairy cows. Journal of Dairy Science 105(5): 4679-4689 Omontese, B.O., Gomes, G.C., Santos, A.R., Silva, L.G., Merenda, V.R., Bisinotto, R.S. (2020) Use of on-farm milk progesterone information to predict fertility outcomes in dairy cows subjected to timed artificial insemination. Journal of Dairy Science 103(7): 6600-6611

CATTLE PRACTICE VOLUME 31 PART 1 2023 14 Practical experiences in using disease data to promote farmer and vet engagement in Johne’s Disease control – The development and impact of the Johne’s Tracker Hanks, J.1 , Orpin, P.2 , Taylor, E.1 , Morrison, R.3 , 1 PAN Livestock Services Ltd, Earley Gate, University of Reading, P.O.Box 237, Reading, RG6 6EU 2 MyHealthyHerd, 519 Saffron Lane, Leicester, LE2 6UL 3 Cranfield Environment Centre, Cranfield University, Cranfield Campus, College Road, Cranfield, MK43 0AL INTRODUCTION Milk ELISA test results for Johne’s Disease (JD) were used from 253 milk recording herds to study the dynamics of the disease and its prevalence in UK dairy herds. Under the guidance of the Action Group on Johne’s, this resulted in a series of key metrics that covered both the prevalence of the disease and, crucially, measures of key drivers of infection and maintenance of the disease in herds. The practical outcome of this research was a range of parameters with benchmark values describing their distribution across the 253 herds. These measures are combined in to the Johne’s Tracker tool which takes data from any ELISA testing herd and displays the range of parameters in a way that highlights the relative strengths and weaknesses in Johne’s control in that herd. With historical test data this can also show how each parameter is changing over time. This description of the disease dynamics, combined with relevant details of the key animals of concern, results in a very constructive background for discussion between veterinarian and farmer. This can include the possible reasons influencing the current disease level as well as the likely impact of past and future management interventions. This talk will describe the key measures of disease and the drivers of infection. A series of case studies will describe the practical application of the tool. These will show how the tool can distinguish between different disease control strategies and their likely consequences. Among the principal disease drivers that will be discussed are: • Priority culls – a distinction between high test cows to identify the most dangerous animals for JD in the herd, based on actual test values and trends over time. Figure 1.

CATTLE PRACTICE VOLUME 31 PART 1 2023 15 • Management response of the farmer to infection – measuring the rate of service and culling of cows after they are identified as having the disease. • New infection rate – the paramount importance of measuring and reducing the rate of index cases. In addition to supporting JD control in individual herds, the Johne’s Tracker has also been used to assess performance across a cohort of herds. The national benchmark values in the Johne’s tracker provide an important reference point for measuring progress by demonstrating the proportion of herds in a vet practice that qualify in the top quartile nationally. Figure 1 shows the % of herds in a vet practice that would qualify in the top quartile nationally for the measure of Average Test Value (ATV). Comparison with earlier data can demonstrate both the overall progress of the practice in controlling disease but also which individual herds are making good progress and also the herds that are failing to improve.

CATTLE PRACTICE VOLUME 31 PART 1 2023 16 Probabilistic predictions of Johne’s disease status through modelling of serial milk antibody ELISA results in combination with milk-recording data Glover, I., Quality Milk Management Services LTD, Cedar Barn, Easton, Wells, BA5 1DU Due to the suboptimal sensitivity of diagnostic tests for paratuberculosis (Johne’s disease; JD), control of this disease in dairy herds in the UK and elsewhere is heavily reliant on serial ELISA testing of individual milk samples; the aim is to infer disease status of each individual animal through the accumulation of information given by repeated quantification of circulating antibodies to Mycobacterium avium subsp. paratuberculosis. Under the current convention, numeric antibody titres are usually classified as “positive” or “negative” according to whether they are less than or greater than a predetermined cutpoint (S/P ratio = 30). High test results (e.g. S/P >= 60, or S/P >= 100) may sometimes be used to indicate a vague but relatively high likelihood of infection, as evidenced by the new ‘Priority Cull’ definition. However, the magnitude of the test result is usually unaccounted for, leading to loss of useful information. Titres very near to the cutpoint are often interpreted in a similar fashion to those further from the cutpoint. Animals are commonly classified according to their perceived status with regards to infection and/or risk of transmission, based on the profile of serial test results. For example, animals are classified as “infected” or “high risk” if they have two positive results (S/P ratio >=30) within three, or sometimes within four, consecutive tests. Animals with some, but fewer, recent positive test results are classified in various ways as “uncertain”. Animals with repeated low antibody titres are classified as “non-infected” or “low-risk”. Such simplistic classification of animals into categories omits important information about the animals’ likelihoods of being infected; animals within one category (e.g. “positive”/”high risk”) may still have different likelihoods of being infected or infectious. Therefore it is desirable to have an indication as to the probability of an animal being infected and/or infectious. JD milk antibody ELISA results are influenced not only by disease status, but also by other factors including age, milk yield and somatic cell count. Failure to account for the influence of these other factors hinders proper interpretation of ELISA test results. Currently available frameworks for interpretation of milk antibody ELISA results are either non-probabilistic (i.e. they simplistically classify animals as “negative”, “unknown” or “positive”), or do not account for magnitude of titre nor influences on antibody titre other than the disease status of the animal. Inappropriate interpretation of test results, and thus inappropriate management and culling of some animals, is inevitable. A Bayesian approach to interpretation of Johne’s antibody titre results, incorporating milk-recording data, is presented, as well as preliminary results of deploying this modelling approach on a cohort of milk-recorded herds. The work presented aims to provide real-time, probabilistic predictions of Johne’s disease status, thereby providing farmers and their advisors with more accurate and intuitive information when managing this disease.

CATTLE PRACTICE VOLUME 31 PART 1 2023 17 The use of economic replacement theory as a tool to support on-farm decision making Clifton, R., Can, E., Hyde, R., Barden, M., Green, M., O’Grady, L., Bradley, A., University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, LE12 5RD Replacement policy of dairy herds impacts on profitability, and it is therefore vital that farmers make the best possible decisions regarding when to replace cows in their herd. In many cases dairy cows are culled because of poor reproductive performance or diseases that impact on welfare and productivity such as lameness, Johne's and mastitis. However, there are situations in which farmers need to determine whether it is more profitable to breed an animal again or whether to replace her. At a more strategic level, knowing the optimum replacement time for animals in a herd can inform on the number of replacements that should be reared. Economic replacement theory can be used to determine the optimum replacement time for animals within a herd. The marginal net revenue (MNR) technique models the economic costs and revenues of cows during their life span, with the aim of maximising net revenues from both present animals and subsequent replacements. The aim of this study was to apply the MNR technique to identify the optimum time of replacement for cows in an example UK dairy herd, and to compare the distribution of time of replacement to culling data for the herd to show how knowledge of optimum replacement times could be useful for reviewing culling practices in dairy herds. A seasonal calving herd with approximately 130 milking cows was used as an example herd. Yearly MNR was calculated for each cow for a period of 10 years from first calving with future revenues predicted by parity based on current data for the herd. Net revenues were then calculated as an annuity per year, with a 5% discount rate per year. All future revenues and costs were weighted by probability of animal survival, with survival defined as 1 – probability of involuntary culling. Retention pay-off (RPO) value of each cow per year was calculated as the total additional profits expected from keeping a cow until her optimum age compared with her immediate replacement, taking account of the chance of involuntary culling. The optimum replacement time for each cow was determined as the time when RPO < 0. The distribution of optimum replacement times for the herd were then compared to culling data for the period 2017-2020. In addition, cows were assigned a ranking based on their retention pay-off value. This ranking could be used by farmers and vets alongside health and fertility information to decide whether cows should be served or replaced. Ultimately, we envisage that information on optimum replacement time for the herd and individual cow RPO values will be presented as part of a culling and replacement report, with further example herds used as case studies. We hope that using the MNR technique can facilitate better management of replacement and culling strategy within a herd and can help farmers and vets to identify opportunities to maximise profit.

CATTLE PRACTICE VOLUME 31 PART 1 2023 18 Demystifying cattle IVF for practitioners Simmons, R., Paragon Veterinary Group, Townhead Farm, Newbiggin, Penrith, Cumbria, CA11 0HT INTRODUCTION To many vets and farmers, IVF (in-vitro fertilisation) or IVP (in-vitro production of embryos) is seen as a fairly new technology, however the first in-vitro produced calf was born in 1987 (Lu And others 1987), less than a decade after Louise Brown (the first IVF baby) was born. Following that milestone over 35 years ago, significant developments were made in the collection of oocytes, production of media and lab protocols through the 1990’s (Looney and others 1994), leading to it becoming an alternative to the ‘conventional’ multiple ovulation and embryo transfer (MOET) method of flushing IVD (in-vivo derived) bovine embryos. The large-scale uptake of IVF commercially started in South America just before the millennium, and followed in North America in the 2000’s (Hasler 2014) and a similar trend is now being seen in Europe. Globally, IVF embryo production surpassed IVD embryo production in 2016, and has accelerated significantly since then (Mastromonaco 2022). The International Embryo Transfer Society figures report over 1.5 million bovine embryos being produced by IVF in 2022, compared to fewer that 390,000 IVD embryos in the same period. With this growth in popularity now occurring in the UK, a greater number of vets on farm will find their clients are considering, or starting to use, IVF to produce embryos. A working knowledge of the basics of IVF, as well as the reasoning for utilising it, helps practitioners to engage with and support their farm clients with their breeding decisions. THE PROCESS The in-vitro production of embryos is made up of a number of processes, all of which must be undertaken with great care and attention to detail in order to be successful. Qualification of success is the production of embryos which, when transferred into good recipients, lead to acceptable pregnancy rates and the birth of healthy, live calves. The processes involved are as follows. Oocyte Collection Oocytes (unfertilised ova) can be collected by two main methods. The first, and most common, is by a technique known as ovum pick-up, or OPU, which involves the aspiration of oocytes from ovarian follicles in the standing donor. OPU is carried out under epidural anaesthesia by a veterinary surgeon, a special ultrasound probe with a needle guide is inserted into the vagina up to the fornix of the cervix. Each ovary in turn is then brought into apposition with the probe through the vaginal wall by per rectal manipulation, allowing the ovary to be clearly visualised and a needle advanced into each suitable follicle. The needle is connected by tubing to a collection vessel, and is held under negative pressure by a vacuum pump. Oocytes are recovered along with surrounding cumulus cells, so are commonly referred to as cumulus-oocyte complexes (COCs). The cumulus cells are sensitive to turbulence during collection, and are important for early support of the oocytes, so care is taken to preserve as much as possible. OPU can also be carried out laparoscopically, particularly in very young donors, but this is not currently practiced in the UK. The second method of oocyte collection is by retrieving the ovaries of donor animals postslaughter, sometimes known as genetic recovery. The ovaries are transported in warm conditions immediately to the lab, where the oocytes are recovered. This is usually reserved for donors at the end of their productive life, or occasionally where a valuable animal has suffered an accident, and only makes up a small proportion of oocyte collections. Collecting high quality oocytes is key to producing high quality embryos and as such good donor management including nutrition, vaccination timing and minimising stress is important. Donors are usually synchronised and then supported with a number of low dose injections of follicle stimulating hormone prior to collection in order to maximise the quality of oocytes, to ensure that they are at the optimal point of their development pathway for the later steps. On average, around 15 to 20 follicles are punctured per donor, with significant variation seen between donors. The collected oocytes and follicular fluid are filtered, with the filtrate searched under a microscope. High quality oocytes are retrieved and graded before commencing the maturation process. In-vitro Maturation Unlike in human IVF, where oocyte collection is timed to be close to the point of fertilisation, with each oocyte fertilised individually, the scale of

CATTLE PRACTICE VOLUME 31 PART 1 2023 19 cattle IVF requires oocytes to be treated as a group. As such, cattle oocytes are collected at a slightly earlier stage and maturation is completed as a group, in an incubator, aided by specially produced media. This lasts around 24 hours, at the end of which the oocytes are ready for fertilisation. In-vitro Fertilisation Oocytes are fertilised with semen from AI straws, either sexed or conventional. The semen is carefully prepared for IVF, with it being centrifuged to remove any dead cells and extender, with only a relatively small number of sperm cells required for fertilisation. These cells are added to media microdrops containing the matured oocytes and left for another 24 hours, although because the oocytes and sperm are in such close proximity fertilisation normally occurs within around 4 hours. In-vitro Culture Fertilised oocytes are supported through a series of different media over the following week, undergoing assessment at each stage. Each media provides for the specific stage of development that the growing embryos will have reached at that point. At the end of the process (7 days after fertilisation) the embryos are carefully graded and can either undergo freezing in liquid nitrogen for storage and later transfer, or can be transferred fresh into prepared recipients. Freezing of embryos tends to reduce the pregnancy rates of the embryos a little, and is restricted to the best embryos, whilst viable embryos judged not to be likely to survive freezing can still be transferred fresh leading to pregnancies. The system does not achieve 100% efficiency. Typically, around 70-80% of oocytes are recovered from the follicles punctured, 80-90% of which fertilise, and around 40% of fertilised oocytes fully develop to blastocyst stage and are judged as viable. THE BENEFITS There are numerous benefits of IVF in cattle. • IVF allows selected donors to greatly increase the number of offspring produced over time. Collections can be carried out fortnightly, or even weekly (depending on the system) and on average produce 5.5-6.0 embryos per fortnight. • OPU can be safely carried out on donors from around 7 months of age, without impacting future fertility or age at first calving. This, along with early identification of high value donors, enables the generation interval to be reduced by a number of months, accelerating genetic progress. • Because oocyte collection does not involve any penetration of the cervix or uterus, it can be safely carried out in pregnant animals in the first trimester. This is especially beneficial for use in show cattle, allowing additional progeny to be produced whilst maintaining optimal calving dates for show season. • IVF is highly semen-efficient. Because only a proportion of sperm cells are required for fertilisation, a single straw of semen can be used to fertilise oocytes from up to 3 donors in a session. This is often carried out when working with rare, or high-value semen. • The combination of enabling higher intensity of selection for breeding by producing multiple calves from the best animals, and reducing the generation interval by collecting from pre-breeding heifers means IVF is a key tool in delivering accelerated genetic progress. Most topically, it can form part of the strategy for more sustainable farming, by breeding replacements from the most efficient and healthy genetics available. There remain areas for improvement in cattle IVF: pregnancy rates still lag slightly behind those of conventionally “flushed” embryos, although the gap is closing (IVF conception rates tend to be 45% with conventional embryos 5-10% better); and IVF embryos still suffer a slightly high rate of pregnancy loss, but the benefits significantly outweigh these remaining challenges as evidenced by the rapidly increasing uptake of the technology. This growth opens opportunities for practitioners to become more involved in advanced breeding technologies, an exciting prospect! REFERENCES Looney, C.R., Lindsey, B.R., Gonseth, C.L., Johnson, D.L. (1994) Commercial aspects of oocyte retrieval and in vitro fertilization (IVF) for embryo production in problem cows. Theriogenology 41: 67–72. https://doi.org/10.1016/S0093- 691X(05)80050-0 Lu, K.H., Gordon, I., Chen, H.B., McGovern, H. (1987) In vitro culture of early bovine embryos derived from in vitro fertilization of follicular ovocytes matured in vitro. In 3. Colloque Scientifique de l'Association Europeenne de Transfert Embryonnaire, Lyon (France), 4-5 Sep 1987. AETE. Hasler, J.F. (2014) Forty years of embryo transfer in cattle: A review focusing on the journal Theriogenology, the growth of the industry in North America, and personal reminisces. Theriogenology 81: 152–169. https://doi.org/10.1016/j. theriogenology.2013.09.010 Mastromonaco, G. (2022) 2021 Statistics of Embryo Production and Transfer. IETS Newsletter Dec 2022

CATTLE PRACTICE VOLUME 31 PART 1 2023 20 Can the type of microscope slide affect my assessment of semen motility during microscopy Nicholson, H., University of Edinburgh and Dyneval Ltd, Roslin Innovation Centre, University of Edinburgh, Easter Bush Campus, EH25 9RG During bull soundnesss examinations, vets are required to assess the % progressive motility of semen through following the World Health Organisation guidelines for semen assessment. Typically, a drop of semen is placed on a microscope slide warmed to body temperature, then covered with a coverslide, and viewed using an optical microscope using a microscope objective around x20 magnification. It is common to observe that the % progressive motility appears different in various parts of the sample and there can be some uncertainty as to the best location on the slide to assess the semen quality. More recently ‘channel slides’ have come onto the market which are filled by capillary action and have a fixed depth along the channel. These are considerably more expensive than the standard microscope slide. To explore whether these offer better measurement capability, an IVOS II computer-aided semen analyser was used to to perform measurements of the % progressively motile (using standardised Qualivets settings) as a function of distance across numerous droplets and channels using a ‘standard’ single batch of post-thawed conventional bull semen straws. Droplets were formed by gently lowering a 24mm-by-24mm square coverslip over a 6µL droplet of a semen straw thawed according to conventional methods, 45 seconds in a water bath at 37 degrees Centigrade. The channel was from a 4-channel Leja slide with a depth of 20µm, filled from position 0 and sealed on both sides with petroleum jelly (Vaseline) before measurements were performed. The same batch of semen and the same preparation protocol was used for both types of sample slide. Our results show the % progressive motility measured for a droplet sandwiched between a coverslip and microscope slide is highly dependent on the position from the edge of the droplet. Measurements varied from 0% progressively motile near the droplet edge (at 0mm and 24mm) to over 50% progressively motile in the centre of the droplet. Measurements performed within a sealed channel have a much flatter profile, independent of the position, if further than approximately 3mm from an edge. In this case, a progressive motility of 30% was measured consistently for nearly 20mm along the length of the channel. This suggests that a channel slide provides results that are more reproducible from user to user. This result was confirmed using an automated Dynecan Semen Analyser which measures thousands of cells each time to provide precise and reproducible results. We interpret the findings as follows. During droplet preparation, outward flow occurs as the droplet is squeezed as the coverslip is lowered. Non-motile cells follow the outward flow so that a higher concentration of non-motile cells are near the edge of a confined droplet. Motile spermatozoa have the capability to swim in all directions, and, as a result, a higher % progressive motility is measured in the centre of a droplet. For a channel, slide flow occurs only while the sample fills due to capillary action and ceases once the channel is completely filled.

CATTLE PRACTICE VOLUME 31 PART 1 2023 21 A comparison of oestrus synchronisation and fixed time AI followed by sweeper bulls to natural service breeding in 3 beef herds Penny, C., Zoetis UK, Birchwood Building, The Office Park, Springfield Drive, Leatherhead, Surrey, KT22 7LP The presentation will summarise a joint project carried out in 2021/22 supported by Livestock Health Scotland and Zoetis UK. The aim of the study was to explore the cost/benefit of synchronising batches of beef cows for single timed AI (TAI) on day 1 of the mating period by comparing performance of AI bred cows to control groups of cows bred to stock bulls. Parameters to be measured included, AI conception rates, calving performance, calving pattern analysis and calf growth rates to weaning. Three spring/summer calving beef herds were enrolled from different geographical areas of Scotland. Following the 2021 calving period each farm identified approximately 50 cows to enrol in a fixed time AI programme with insemination occurring on day 1 of the normal mating start date (MSD). Control cows were bred to stock bulls as per the normal herd mating period. Cows were synchronised with the following protocol: day 0 CIDR inserted + injection of GnRH, day 7 injection of PG, Day 8 or 9 CIDR removal (+ 400iu PMSG in selected cows calved <55 days at MSD), single TAI at 56 hrs after CIDR removal with conventional beef semen. Sweeper bulls were introduced from the day after TAI and left in with cows for the same period as the control cows. Conception rate to TAI was confirmed by ultrasound pregnancy diagnosis and averaged 59%. Subsequent 2022 calving data was collected for all cows and weaning weights were available in 2 of 3 herds. The final pregnancy and calving results are summarised in Table 1. Barren Rate Assisted Calvings Calf Mortality Calved in 1st 3 weeks Weaned calf crop 2022 Weaned calf weight AI groups 4% 2% 0.7% 78% 96% 305kg Control 11% 10% 7% 44% 82% 280kg AI System Advantage -7% -8% -6% +34% +14% +25kg Table 1. Assuming the average production gains seen in these 3 herds could be replicated, then a simple cost/ benefit calculation was calculated for 100 beef cows bred either to AI/sweeper bulls or bulls alone. • Cost of synchronisation/AI was estimated at £5000 (£50/cow) • Value of 14 extra weaned calves estimated 14 @ £700 = £9,800 • Value of weaned calf weight premium of 25kg/calf weaned x 96 x £2.50 = £6,000 Cost/benefit = £108 per cow bred The cost/benefit of breeding groups of beef cows by synchronisation/AI is driven by achieving a target AI CR of 60%, superior weaned calf crop %, and heavier calves generated by more compact calving and superior genetics. Other benefits include the ability to generate superior heifer replacements by introducing maternal trait sires or using sexed semen.

CATTLE PRACTICE VOLUME 31 PART 1 2023 22 Participatory development of a National code of prescribing conduct and prescribing guidelines for farm vets in Wales Rees, G., Powell, A., Aberystwyth University School of Veterinary Science, Department of Life Sciences, Aberystwyth University, Penglais Hill, Aberystwyth, Ceredigion, SY23 3FL Arwain DGC is a national collaborative programme funded through Welsh Government aimed at improving responsible antimicrobial use in cattle and sheep in Wales. Aberystwyth University has been leading the Veterinary Prescribing Champions programme as part of Arwain DGC. The Veterinary Prescribing Champions (VPCs) are a network of highly trained and motivated veterinary surgeons representing around 90% of all Welsh veterinary practices who service farm animals. The network was initially recruited in 2019 and has received an ongoing programme of training in responsible veterinary medicine use, alongside discussion sessions, workshops and other in person and online events. The VPC network has also been responsible for creating and delivering several important outputs, including policy recommendations and designing and implementing antimicrobial stewardship interventions within practice. Most recently, the VPC network has worked together with Aberystwyth University and the wider Arwain DGC project to develop two key outputs for the profession with the aim of improving prescribing within the profession. These outputs are a voluntary code of prescribing conduct for Welsh veterinary practices, and a series of prescribing guidelines for key diseases of farm animals in Wales. From the wider VPC network of 52 vets, two working groups were formed in 2021. One working group (n=7) was formed in order to develop the code of prescribing conduct, whilst another discrete group (n=6) was tasked with establishing the clinical treatment guidelines. The membership of these working groups is solely made up of practising vets from farm practices working within Wales supported and facilitated by academic researchers from Aberystwyth University. 1. Voluntary Code of Prescribing Conduct The Code of Conduct Working Group met six times (twice face-to-face, and four times remotely) over a 12-month period to develop their draft output. This working group’s aim was to develop a code of conduct, to which practices across the wider Welsh Veterinary profession could voluntarily subscribe. Initial discussions identified pertinent and timely professional themes which could directly impact upon animal health and welfare, professional integrity, client relationships, and ultimately, prudent antimicrobial use and accurate recording. Via an iterative process, the group then discussed specific word use to accurately define key phrases and definitions to minimise any variation or misconstrued interpretation of the code, and resultant standards of prescribing and animal care. The two main themes were: • Under care: Towards creating a core prescribing practice (CPP), with minimal standards of farm visits and knowledge; • Responsible use: Defining justified antimicrobial use for susceptible disease agents, specifying sufficient clinical information, client engagement and reporting treatment outcomes. Following a subsequent VPC consultation process, feedback from the wider Welsh veterinary profession was considered and incorporated into a final Code of Conduct. 2. Prescribing Guidelines for key diseases Clinical Guideline Working Group members met eight times (four times remotely and four times face-to-face) over a 14-month period in order to develop these guidelines. Six key diseases were selected as representing important diseases to Welsh practitioners, where guidance would be most valuable with three of these being diseases of cattle. These diseases are: • Neonatal enteric disease • Mastitis – focus on dry cow therapy • Bovine respiratory disease Three sheep diseases were also selected: • Watery mouth • Lameness • Joint ill Extensive literature reviews were conducted by the research team in order to provide an up-todate evidence base for the guidelines. The working group then met several times, considering the evidence base alongside their extensive clinical experience and develop a series of treatment guidelines that would not only be informed by the

CATTLE PRACTICE VOLUME 31 PART 1 2023 23 best quality evidence but would also be practical and relevant to practitioners working in Welsh veterinary practices. The draft guidelines, once complete, were circulated among the wider VPC network for comment and for wider consultation among key stakeholders. The refined Codes and Guidelines will be launched to the profession at the Vets Conference in Aberystwyth in June 2023 and will be available in their final form for presentation and discussion at BCVA Congress 2023.

CATTLE PRACTICE VOLUME 31 PART 1 2023 24 Better understanding the associations between antimicrobial use and resistance through active surveillance of AMR on cattle and sheep farms across Wales Best, C.M., Vass, L., Mounsey, O., Sealey, K., Llamazares, B., Moiseienko, Y., Miller, W., Bettridge, J.M., Sealey, J.E., Dowsey, A.W., Avison, M.B., Reyher, K.K., Bristol Veterinary School, University of Bristol, Langford House, Langford, Bristol, BS40 5DU Arwain DGC is a national collaborative programme funded through Welsh Government aimed at improving responsible antimicrobial use in Wales. The University of Bristol has been leading the active surveillance of antimicrobial resistance (AMR) on cattle and sheep farms. This project is on-going and is due to complete in June 2023. Final results will be presented at BCVA Congress 2023. This presentation is intended to stand alongside other Arwain DGC presentations being offered to BCVA Congress 2023. A convenience sample of 54 farms (21 dairy, 11 beef, 10 sheep, 12 beef and sheep) across Wales were recruited, reflecting a variety of management systems. Participating farms from 13 veterinary practices were visited monthly by a representative from their registered veterinary practice. At each visit, samples were collected from a range of faecally contaminated environments and livestock groups on farm, using sterile over-boot socks or by directly collecting faeces into tubes using gloved hands. Samples were posted to the laboratory at the University of Bristol where they were tested for Escherichia coli resistant to one or more Category C and D antimicrobials - amoxicillin, amoxicillin-clavulanate, tetracycline, spectinomycin (sheep samples only) or streptomycin (cattle samples only), using an established phenotypic AMR detection method. Samples were also tested for E. coli resistance to the Category B antimicrobials: 3rd generation cephalosporins and fluoroquinolones. Individual representative isolates were selected for whole genome sequencing. Alongside the surveillance of AMR, 12-month retrospective and prospective antimicrobial use (AMU) data captured from the Welsh Lamb and Beef Producer’s AMU Calculator have been collated for each participating farm. Data concerning the management, health and performance of livestock on participating farms have also been collected through comprehensive questionnaires administered by veterinary surgeons. Bacteriology results indicate that farm- and sample-level positivity for E. coli resistant to Category C and D antimicrobials was high, with some variation in sample-level positivity observed over time. Whilst positivity was high across all species, samples from sheep appear more frequently positive, although this might be explained by sheep excreting more E. coli than cattle. Early analysis of resistance to Category B antimicrobials indicates sample-level positivity to be low, with resistance detected sporadically on a small number of farms, predominantly dairy farms, though on some farms, resistance was identified in multiple successive visits. Further exploration will assess how climate and sample type (representative areas and species age groups) impacts positivity rates for resistance. An evaluation of the risk factors for resistance is underway to better understand and manage AMR in the farm environment. Results from genome sequencing suggest a wide variety of E. coli and resistance mechanisms are present on participating farms. So far, two different mechanisms for amoxicillin-clavulanate resistance have been identified, one of which has not previously been associated with amoxicillin-clavulanate resistance in E. coli. These mechanisms have both been found genetically linked to an identical spectinomycin/streptomycin resistance gene, potentially explaining why sheep carry amoxicillin-clavulanate resistant E. coli, despite amoxicillin-clavulanate not being licenced in sheep. This could, in part, also explain an observation that streptomycin resistance rates in beef cattle on mixed beef and sheep farms are higher than in cattle on beefonly or dairy farms, given the historic use of spectinomycin in sheep. Preliminary genomic analyses have also identified instances where farm-to-farm transmission of near-identical isolates has occurred, mainly involving samples from sheep and between farms up to 100 miles apart - possibly a result of the movement of sheep across the country. Analysis of farm management and livestock health data will help illuminate the risk factors for the dissemination of resistant bacteria within AMR transmission networks on - and between farms.

CATTLE PRACTICE VOLUME 31 PART 1 2023 25 Final results presented will include, but are not limited to, findings and discussion surrounding the: • Location of AMR hotspots on farms; • Effect of time of year, animal age group and location on prevalence of AMR; • Regional differences between types of AMR present; • Extent of transmission of AMR genes around the farm and between farms; • Current picture of AMU on farms across Wales; • Associations between AMU and AMR on farms; • Risk factors associated with both higher AMU and levels of AMR; • Evaluation of sampling procedures and their suitability for ongoing AMR surveillance.

CATTLE PRACTICE VOLUME 31 PART 1 2023 26 From ‘knowing’ to ‘doing’ – Is veterinary medicine currently utilising the potential offered by the field of implementation science? Reyneke, R., University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, LE12 5RD Veterinary medicine has a widely acknowledged ‘gap’ between research and practice, with many examples of circumstances where proven evidence-based practices are not being successfully implemented (Hamilton 2018). This ‘research to practice gap’ is not solely a challenge of veterinary medicine but has also been well documented in human healthcare. It has been reported in human healthcare that it takes on average 17 years for research findings to be integrated into routine practice, and even then, not all evidence-based practices make it into general clinical usage - about half of them never make it this far (Balas and Boren 2000). One key reason for this is that traditionally the focus has been on education of stakeholders. However, successful implementation requires more than the transfer of knowledge alone. When interviewed about what challenges faced the veterinary profession, one veterinary respondent captured this; “it's not knowing more stuff that we need—we need to basically to be able to implement it better” (Ruston and others 2016). Implementation science was formed to address the challenges involved in improving the uptake of evidencebased practices in human healthcare. This is the study of methods that aid the uptake of evidence-based practices and other research findings into clinical practice, with the aim of improving provision of health care. Implementation science takes learnings from a variety of other fields including health behaviour change and social psychology. As a core component of implementation science, formal constructs (theories, models and/or frameworks) are used to guide, explain and/or evaluate the process of implementation, however the extent of the awareness about this approach and its use in veterinary medicine is unknown. A scoping review was conducted with the aim of characterising existing veterinary uses of theories, models and/or frameworks to inform the uptake of evidence-based practices, and to identify the focus of these applications. Searches were conducted in multiple literature databases and the grey literature (materials and research that is available through channels outside of commercial publishing). The search strategy was comprised of a list of known existing theories, models and/or frameworks that have been used to implement evidence-based practices in human health, alongside more generic terms for implementation and terms relevant to veterinary medicine. Studies from both peer reviewed journals and the grey literature were included if they were relevant to veterinary medicine and described the use of a theory, model and/or framework to inform the uptake of and evidence-based practice(s). Sixty-eight studies meeting the eligibility criteria were identified. These covered a variety of countries and evidence-based practices. Twenty-eight different theories, models and/or frameworks were used, however the Theory of Planned Behaviour was the most common, being used in 46% of the studies included (n=31). The most common aim of the usage of a theory, model and/or framework was to understand and/or explain what influences implementation outcomes (n=65, 96%). Only a small proportion of papers (n=8, 12%) described the use of a theory, model and/or framework in association with the actual implementation of an intervention. The remaining 60 papers (88%) all involved gathering information that would be relevant to an implementation effort should one be attempted, but without actuation of any implementation. The review highlighted that to date there has been some use of theories, models and/or frameworks to improve the uptake of evidence-based practices in veterinary medicine, however this has been reasonably scarce. Existing work has chiefly had the aim of understanding factors that may influence the outcome of an implementation effort, such as barriers and facilitators, with the usage of ‘classic theories’ (such as the Theory of Planned Behaviour) being heavily relied on. Furthermore, in most cases the knowledge gained is not then directly applied to the actual implementation of an intervention. In addition, key factors to ensure successful implementation are often neglected, such as acknowledgement of wider contextual factors and consideration of achieving long term sustained usage of interventions. The usage of theories, models and/or frameworks to improve the uptake of evidence-based practices is currently underutilised in veterinary medicine and there

CATTLE PRACTICE VOLUME 31 PART 1 2023 27 is clear scope for increasing and expanding this approach. Alongside this, it would also be highly valuable to further develop interdisciplinary collaborations with human implementation experts. REFERENCES Balas, E.A., Boren, S.A. (2000) Managing clinical knowledge for health care improvement. Yearbook of medical informatics 9: 65-70 Hamilton, L. (2018) Bridging the divide between theory and practice: taking a co-productive approach to vet-farmer relationships. Food Ethics 1: 221-233 Ruston, A., Shortall, O., Green, M., Brennan, M., Wapenaar, W., Kaler, J. (2016) Challenges facing the farm animal veterinary profession in England: A qualitative study of veterinarians’ perceptions and responses. Preventive Veterinary Medicine 127: 84-93

CATTLE PRACTICE VOLUME 31 PART 1 2023 28 Monitoring Flukicide Anthelmintic and Ecto-parasiticides (FAEcto) use in dairy farms in South West Scotland Watson, E., More, J., NMR Plc, Fox Talbot House, Greenways Business Park, Chippenham, SN15 1BN BACKGROUND Flukicide Anthelmintic and Ecto-parasiticides (FAEcto) are widely used in the UK dairy industry out with the direct prescription of veterinary practices. As a result, the levels and appropriateness of use are relatively unknown. International Medical Statistics (IMS) provide sales data for Flukicide Anthelmintic and Ecto-parasiticides, whilst providing a good indication of the major usage of compounds within a therapeutic/chemical group, it may not represent total sales. An over reliance on FAEcto products to manage parasite problems will have a detrimental effect on ecosystem and lead to increased levels of resistance of the products. Detailed advice on sustainable worm control strategies are available. However additional tools are required to change existing usage patterns and engage users more effectively. The aim of the pilot study was to create a methodology to monitor FAEcto usage in dairy farms in South West Scotland, engage stakeholders effectively and consider its wider application for U.K. dairy industry. Method Annual purchase data of Flukicide Anthelmintic and Ecto-parasiticides were collected for 20 dairy farms. Unlike antibiotic use, there are no industry standard methods to measure use of parasiticides. We will present worked examples on our selected metrics for use by active ingredient (mg/kg) and doses (DCD) based on the product type by intended use (for example endectocide, ectoparasiticide, anthelmintic, flukicide and anti-protozoal), by ingredient type (for example benzimidazoles, macrocyclic lactones, synthetic pyrethroids etc.) based on cattle age group(s) (youngstock and adults) at risk of treatment for each product. Result **These results are provisional and we expect to update the abstract with full results prior to presentation** Provisional data analysis show an average DCD of 7.05 (interquartile range 3.35-8.36) for all parasiticide use. On average there were just over four treatment courses per animal at risk of treatment with an endectocide (DCD 4.39) and just under two treatment courses (DCD 1.82) for ectoparasiticides. Mg/kg ranged from 0.57 to 25.70 with a mean of 7.15. There was a significant reliance on Macrocyclic Lactone 36% of all doses and virtually 100% of all anthelmintic doses. Figure 1.

CATTLE PRACTICE VOLUME 31 PART 1 2023 29 CONCLUSIONS Using monitoring metrics based on previously used antibiotic monitoring as a basis for FAEcto monitoring means the general concept is already accepted by the dairy industry and target stakeholders. Using this monitoring methodology allows benchmarking of usage and can be used to stimulate conversations with clients on their attitudes to the use of FAEcto products. This may become increasingly important where the prophylactic use of veterinary medicines is reviewed.

CATTLE PRACTICE VOLUME 31 PART 1 2023 30 Benchmarking antimicrobial usage on UK dairy herds – Actionable insights from the last 5 years Rowland, K.1 , Ford, C.1 , Potter, T.2 , 1 Kingshay Farming and Conservation, Glastonbury, Somerset, BA6 8LU 2 Westpoint Farm Vets, Dawes Farm, Bognor Road, Warnham, West Sussex, RH12 3SH The Veterinary Antimicrobial Resistance and Sales Surveillance 2021 report showed that overall, UK antibiotic sales for food-producing animals have reduced by 55% since 2014. This significant reduction highlights the success of the collaborative approach between everyone working in UK agriculture to ensure antimicrobials are used responsibly. The Kingshay antimicrobial monitoring service was established in 2017 in response to demands from farmers, vets, and milk processors to enable antimicrobial purchase data to be collected on an annual basis. This data has then been used as part of the health planning process enabling farms to reduce and refine their use of antimicrobials. The number of herds using the service has grown year on year with 1,044 herds being recorded in 2022. For each herd, the livestock numbers were collected from each producer and the antimicrobial purchases were collected from the vet practice. A set of validated reports were then created and sent out to the producer/ vet to check all products were included and validate the accuracy of the report content. Any products that were not used in the period were adjusted as well as any products used on other enterprises, such as beef or sheep. All producers and vets receive a summary report for their individual herd(s) benchmarked against other producers for the same period and also the previous year. The farmer report contained a comparison to the targets for antimicrobial use, along with administration routes, antimicrobial class and dry cow therapy. This presentation provides an overview of the trends and insights from the last five years of recording. There has been an overall 27% reduction in usage since 2018, however the usage has plateaued in the last 3 years rather than reducing further. When comparing to industry targets, 76.5% of herds are now below RUMA’s previous target of 21mg/PCU set in 2017. Across the 1,044 herds analysed in 2022 the overall usage ranged from 0.26 to 87.17mg/kg PCU. There are still improvements to be made, particularly in the highest 25%, which are contributing 49% of the overall antimicrobial usage. The RUMA Targets Task Force 2 set out targets for dry and lactating cow tubes. For sales of lactating cow tubes, the aim was for a year-on-year reduction from 0.69 DCDVet, which has been achieved. For the sales of dry cow tubes, the aim was a year-on-year reduction from 0.59 DCDVet which again has been achieved. The proportion of herds using teat sealants has remained relatively static over the last 4 years with 67% of herds using teat sealants in 2022. Over the recording period there has been a dramatic reduction in the percentage of herds using Critically Important Antimicrobials (CIAs) from 79.1% of herds in 2018 to 6.7% of herds in 2022. In 2022 Penicillin based products still contribute the highest mg/kg PCU of all the antimicrobial classes but have seen a reduction year-on-year. There has been a continued increase in the usage of tetracyclines over the last 5 years which is likely to be driven by the adoption of these Prudence (Category D) products in favour over other products. Whilst many herds have made substantive reductions in their usage over their periods of benchmarking, within the highest 25% of antimicrobial users, 49% of herds had stayed in that quartile in both 2022 & 2021, with 40% of those herds increasing in antimicrobial use on the previous year. This again highlights the need for further work to be focussed on the higher users in order to bring about significant and consistent reductions in antimicrobial usage across the UK dairy sector. The data showed no correlation between antimicrobial usage and herd size or milk yield. Analysis by region found herds in the South/South-East regions to have the lowest use, averaging 13.0mg/kg PCU and the North region to be the highest at 20.7mg/kg PCU. A more detailed analysis would be needed to understand why these differences exist, as herd size and milk yield suggests similarities between all regions. For all herds, injectable antimicrobials make up the largest proportion of their antimicrobial usage (ranging between 70% and 76%) and reductions in this area highlight the biggest opportunity for reducing overall herd usage. The data highlights the high usage of oral antimicrobials in herds within the highest 25% of users with herds in this quartile using on average 4.3mg/kg PCU which is 4 times as much as herds in the 3rd quartile

CATTLE PRACTICE VOLUME 31 PART 1 2023 31 and 43 times as much as herds in the lowest quartile. Oral administration to groups of animals has been highlighted by the EMA as having the highest estimated impact on antimicrobial resistance and this highlights a potential focus for further reductions on certain herds. SUMMARY The data presented highlights the significant reductions in antimicrobial usage achieved in the UK dairy sector over the last 5 years. As veterinary surgeons work with their clients to reduce the usage of antimicrobials further, the data presented highlights the need for a more targeted and bespoke approach dependent on an individual farms’ specific disease challenges and antimicrobial usage patterns. To achieve further reductions across the industry vets and farmers need to focus on how injectable products are being used and how their use can be reduced. The significant contribution of the highest 25% of users to the overall antimicrobial usage highlights the need for vets and advisors to focus their attention on the less engaged clients, whilst still maintaining the momentum with those farms that have already made reductions.

CATTLE PRACTICE VOLUME 31 PART 1 2023 32 What are the challenges faced by new graduates when making antibiotic prescribing decisions? Vallis, R., Wood, S., Bristol Veterinary School, Langford House, Dolberry, Bristol, BS40 5DU BACKGROUND As new graduates enter farm animal practice it is imperative that they have the confidence to prescribe antibiotics appropriately and a working knowledge of antimicrobial stewardship (AMS). The importance of AMS is widely recognised as critical in minimising the risk of antimicrobial resistance (AMR) within both veterinary and human medicine. The farm animal veterinary sector has been a particular area of focus for improved AMS due to concerns about resistance developing from antimicrobial use in agriculture and the food industry (O’Neill 2016, Manyi-Loh and others 2018). RCVS Day One Competences require new graduates to ‘prescribe and dispense medicines correctly and responsibly’; as well as ‘develop appropriate treatment plans and administer treatment in the interests of the patient and with regard to the resources available and appropriate public health and environmental considerations’ (RCVS 2022). Students are provided with teaching that pertains to this throughout the veterinary degree. The aim of this study was to understand the level of knowledge final year veterinary students at Bristol Vet School had on AMS in food producing animals, and their perceptions of the teaching on this subject during their veterinary studies. METHODS Participants were recruited from the 2021/22 final year cohort of the Bachelor of Veterinary Science degree at University of Bristol. A mixed methods approach was used to explore perceptions and knowledge of veterinary students on responsible use of antimicrobials in food producing animals. Students were invited to complete an anonymous online survey based on a similar study in Australia (Hardefeldt and others 2018). Focus groups investigated key topics in more detail. Descriptive statistics were used to analyse results from the survey. Thematic analysis was carried out on transcripts from the focus groups. RESULTS AND DISCUSSION Three quarters of participants were able to correctly identity the first line antibiotics listed within the survey, with all correctly identifying oxytetracycline as first line. There was more confusion classifying second and third line antibiotics. For example, streptomycin and amoxicillin clavulanate are classified as second line in European Medicines Agency guidelines (EMA 2019), however, around a quarter or participants classified these as first line. These results may partly reflect the students’ teaching, with a focus on recognising first line antibiotics. It is possible the frequency that students are exposed to second line antibiotics in practice impacts on students placing them as first line antibiotics. Participants were asked how likely they were to prescribe antibiotics in 10 clinical scenarios. Scenarios were chosen that were common to farm animal practice and represented cases where antibiotics are either highly likely or not likely at all to be administered. Results varied between scenarios. Over 80% of participants stated they would rarely prescribe antibiotics to a lame cow, however some scenarios such as ‘a cow with moderate mastitis’ created opposing views on whether antibiotics should be used. The decision-making process for prescribing antibiotics was discussed in focus groups, which explained some of the variation in responses seen in the cases. Participants described how they would consider all aspects of the case to decide upon treatment. This included acknowledging the importance of a clinical exam “We’d want a bit more information about the cow, like has she got a temperature and that kind of thing, and that might influence [antibiotic prescribing]”. Participants also discussed how they were drawing upon knowledge from both practice and lectures to decide upon treatment. “Last week we saw a similar situation but dairy rather than beef… they had a few calves that did have pneumonia and we did give them antibiotics, so having seen it done in practice that might influence my decision as I’ve seen it done before”.Participants commented on the importance

CATTLE PRACTICE VOLUME 31 PART 1 2023 33 of EMS and experiences gained here “I think from teaching I’ve got more… how to approach a case, how to take… a history, and … thinking about signalment, but diagnosing and practical aspects of treating these conditions on farm has come from EMS”. However, they sometimes find it challenging to have discussions regarding antibiotic choice with vets in practice: “on a case, if they’ve given three drugs….and they haven’t said what any of them are, like antibiotics, pain relief, then you spend so long asking what one of the is you don’t really have time to cover what they’ve given before the next call” This data highlights the important role that practitioners play in supporting development of clinical reasoning skills needed to manage cases. When deciding whether to use antibiotics or not, participants stated that they would benefit from a resource to aid them further with their decision making regarding antibiotic use. With regards to teaching, 89% of participants agreed that they had a good understanding of what AMS is and 72% agreed that they understood AMR mechanisms. However, it was discussed that they would benefit from more clinical application of AMS earlier on in the veterinary course. Participants mentioned that they struggled to draw upon knowledge from pre-clinical pharmacology teaching when making decisions for clinical scenarios, and that this teaching could be more integrated. CONCLUSIONS The results from this study give an insight into student’s confidence levels with prescribing antibiotics in farm animal practice. Although students at Bristol Vet School understand the principles of AMS and can correctly classify first line antibiotics, their confidence in ability to prescribe could be increased using clinical application of teaching throughout the veterinary course, exposure to appropriate use of antibiotics and discussions pertaining to this whilst in practice, and access to more detailed guidelines for prescribing. REFERENCES European Medicines Agency (2019) Categorisation of antibiotics for use in animals for prudent and responsible use. [https://www.ema.europa.eu/en/documents/report/ infographic-categorisation-antibiotics-use-animals-prudentresponsible-use_en.pdf] Hardefeldt, L., Nielsen, T., Crabb, H., Gilkerson, J., Squires, R., Heller, J., Sharp, C., Cobbold, R., Norris, J., Browning, G. (2018) Veterinary Students’ Knowledge and Perceptions About Antimicrobial Stewardship and Biosecurity—a National Survey. Antibiotics 7(2): doi: 10.3390/antibiotics7020034. Manyi-Loh, C., Mamphweli, S., Meyer, E., Okoh, A. (2018) Antibiotic Use in Agriculture and Its Consequential Resistance in Environmental Sources: Potential Public Health Implications. Molecules 23: 795. https://doi.org/10.3390/ molecules23040795 O’Neill, J. (2016) Tackling Drug Resistant Infections Globally: Final Report and Recommendations. The Review on Antimicrobial Resistance; Government of the United Kingdom: London, UK RCVS (2022) RCVS Day One Competences. 2022 edition.  [https://www.rcvs.org.uk/news-and-views/publications/rcvsday-one-competences-feb-2022/] Figure 1.

CATTLE PRACTICE VOLUME 31 PART 1 2023 34 Encouraging antibiotic stewardship on smallholdings and amongst farm animals kept as pets Scott, C., Buller, H., Reyher, K., Bristol Veterinary School, Langford House, Langford, North Somerset, BS40 5DU BACKGROUND Smallholders in the UK generally operate with fewer opportunities for regulation than larger, more commercial, farms, often acting outside of farm assurance or supermarket contracts. The effects of this and other factors, such as often having different veterinary oversight, are currently unknown for antibiotic use (ABU). Therefore, this research aimed to explore ABU on smallholdings, especially understanding the effects of factors that differentiate smallholders from larger, more commercial, farms. METHODS Suitable holdings were recruited purposively to achieve a heterogenous sample. Participants were approached by the researcher or replied to a social media post on specific social media pages introducing the research. 29 participants who agreed to take part in the study and were within a 3 hour driving radius of Bristol Veterinary School were visited 2-3 times over 2021 to 2023. Participants holdings ranged from 2 to ~250 animals of 1-8 species and included both small-scale producers and farm animals kept as pets. Semi-structured interview techniques were used to gain an holistic understanding of health management practices, to discuss the role of vets on smallholdings, to understand attitudes around antibiotic resistance and ABU and to elicit examples of ABU so that ABU practices could be explored. Techniques included listing and ranking participants’ knowledge resources for animal health management, a farm walk where participants took the researcher around the holding discussing each group of animals in turn and a calendar where participants recorded and described instances of ABU over the last year. Interviews were audio recorded, transcribed and analysed using thematic analysis with NVivo computer software, where codes and key themes were derived from the data. RESULTS Smallholders in the study characterised themselves as fundamentally different from larger, more commercial farms in their ABU practices, instead describing extensive, low input and natural systems where ABU reliance or overuse was unnecessary. Subjectively, despite variable adoption of vaccination and biosecurity practices (e.g. isolation of new stock) clinical signs of disease were uncommon and ABU was low. Nevertheless, despite these antibiotic stewardship intentions, response to disease signs, or a perceived high risk of disease, appeared constrained to antibiotics and ‘pain-relief’ as a standard, first-line response. In most cases, regardless of veterinary involvement, antibiotics were reportedly used without establishment of a diagnosis or as a prophylaxis against possible future infection, such as for unspecific clinical signs or following birthing interventions. This was defended by some smallholders as necessary to protect animal welfare, given that animals were unable to communicate their specific ailments, and reflective of the complexities around diagnosing the cause of clinical signs and the speed by which animals were considered to deteriorate in condition. In this way, as well as a perception that vets set the example of such ABU practices and a view that smallholder ABU was inconsequential in comparison to antibiotic overuse amongst commercial farmers, antibiotics were characterised as a justified first step in many cases. When administering antibiotics, many smallholders described the usefulness of ‘broadspectrum’ products for cases of unspecific clinical signs or for prophylaxis, rather than referring to particular antibiotics being appropriate for particular diagnoses. Alongside other factors, this led to veterinary oversight often not being sought for first-line treatment. Instead, commercial farmers, fellow smallholders and online resources could be consulted, described by smallholders as able to provide more expedient and, at times, more straight-forward veterinary advice. This was especially apparent for species discussed as ‘specialist’, such as poultry and pigs, where some participants felt they did not have appropriate access to a vet and were therefore obliged to seek

CATTLE PRACTICE VOLUME 31 PART 1 2023 35 alternative advice. Many smallholders described a preference to collect individual antibiotic courses in syringes from their vets. However, ABU without veterinary direction was most commonly encountered in examples where whole bottles had been prescribed by vets to farms. This was either in the form of ’standing medicines packs’ for the holding or via ‘leftover’ antibiotic from previous cases of disease. In these cases, smallholders were often not aware of the specific conditions for which antibiotics should be prescribed but were instead used as smallholders saw fit. Finally, antibiotics were also shared between holdings, as well as from larger commercial farms. CONCLUSIONS This study raises important considerations for vets seeking to achieve responsible ABU on smallholdings. If this is to be achieved in full, the veterinary community will be required to evaluate which instances of ABU constitute appropriate use and consider how we restrict ABU to only these cases, whilst balancing animal welfare and the vetclient relationship. Furthermore, these findings suggest that the current model for farm veterinary provision may require adaptation and adjustment to the specific needs of smallholders. This includes ensuring veterinary confidence for common smallholding species which may be considered ‘specialist’ by the veterinary community. Veterinary communication of ABU on smallholdings could be improved by consistently ensuring the process of clinical reasoning and identification of differential diagnoses is clearly communicated to smallholding clients, with a thorough explanation of why a particular antibiotic is appropriate for a particular instance. Furthermore, practice protocols for leaving whole bottles of antibiotics on smallholdings could be revised to involve ensuring that clients are fully aware of the instances in which they should be used and the legislation around the prescription of antibiotics, such as sharing of medicines between holdings. This could be appropriately achieved using written smallholdingspecific veterinary health plans, associated health planning visits and smallholder education schemes. Such schemes have the potential to improve overall health management practices amongst smallholders and further reduce need for ABU, as well as allow a formalised mechanism for training around the application of medicines, which could impact appropriate ABU.

CATTLE PRACTICE VOLUME 31 PART 1 2023 36 Tools and tips to engage farmers with the control of infectious diseasecase studies using Johne’s Disease as an example Orpin, P.1 , Hanks, J.2 , Morrison, R.3 , 1 MyHealthyHerd, 519 Saffron Ln, Leicester, LE2 6UL 2 PAN Livestock Services Ltd, School of Agriculture, Policy and Development, University of Reading, Earley Gate, P.O. Box 237, Reading, RG6 6EU 3 School of Water, Energy and the Environment, Cranfield University, College Rd, Wharley End, Bedford, MK43 0AL Successful engagement of farmers with robust disease control is a core skill required of any large animal vet wishing to progress. The purpose of this interactive workshop is to identify areas of difficulty utilising the Mentimeter tool and then to demonstrate how these areas of challenge can be overcome using Johne’s Disease control as an example. The areas that will be covered • Identifying farmer needs. • The importance of trust and relationships. • Infectious disease principles. • Progressing farmers from interest to full engagement. • Maintaining momentum. • Demonstrating progress at herd and practice level. • Tools and techniques that can be used to analyse, engage and motivate. • Sharing our experiences with 40 vet practices and 400 farmers within a BBRSC funded project investigating the roadblocks to control of Johne’s Disease in dairy herds. A series of case studies will be used to give participants example of a range of different scenarios that you are likely to be presented with when looking to control this disease. The authors will use their extensive experience to offer tips and guidance on the different messages that are required in different scenarios, and how different messages are best discussed with farmers. This will be extremely informal and interactive.

CATTLE PRACTICE VOLUME 31 PART 1 2023 37 Bovine reproductive manual and ultrasound examination May, P., Bovine Health & Reproduction, 10 Sambre Road, Ridgeway View, Chisledon, Swindon, Wiltshire, SN4 0JB This workshop is to share my experience of bovine reproductive ultrasound over the last nearly 40 years. The workshop uses both slides and videos to enable attendees to undertake the procedures demonstrated. The practical element of rectal palpation including uterine flipping is fully discussed and demonstrated as well as sharing ultrasound images. Combining gentle palpation with ultrasound use will help accurate placement of the ultrasound enabling improved accurate imaging. The presentation starts with observations of the normal oestrus cycle. Looking in more detail should help define at what stage of the cycle your patient is and help improve your fertility treatment efficacies. This is followed by aging the bovine foetus, using the scanner and manual palpation techniques can be very useful in accurately determining later gestation stages. Foetal death plus some abnormal foetuses comes next, then how to easily find twins during your routine visit. Multiple pregnancies should always be determined to allow your client to manage the dam safely before her next birth. Ultrasound gender determination is the next section with plenty of videos to help. The final section shares some recent observations including subclinical endometritis, follicular counting, persistent follicular structures plus Ovum Pick Up techniques.

CATTLE PRACTICE VOLUME 31 PART 1 2023 38 Teaching and training skills for farm vets O’Malley, P., Angel, T., Synergy Farm Health Ltd, The Transmission Hall, Rampisham Business Centre, Rampisham Down, Dorset, DT2 0HS ABSTRACT The role of the modern farm vet continues to evolve. Education and training of farmers and their staff, colleagues and peers, and veterinary students are all common place in modern farm practice. This teaching can take place formally and informally in a variety of settings. Teaching may vary from a brief cow-side demonstration to a new member of farm staff, to a structured course offered as a chargeable service to clients. This workshop will consider best practice in adult education as it applies to farm veterinary practice. During the workshop we will consider what good teaching looks like; considering different types of learners, the different learning environments, and the sort of learning outcomes we are hoping to achieve. Attendees of the workshop will learn some of the theory that underpins adult education and apply this theory to their current teaching and training experiences. We will share experiences on what works (and what doesn’t!) including practical tips and tricks on how to make training both impactful and enjoyable. Whether you teach vet students, deliver farmer meetings, or want to develop how you deliver on farm training to your clients, there will be something for you in this workshop.

CATTLE PRACTICE VOLUME 31 PART 1 2023 39 EMS – Better for you and better for the student Davies, H., Lawrence, R., Sanford, M., Robson, I., University Of Surrey, vet school main building, Daphne Jackson Road, Guildford, GU2 7AL Surrey Vet School, now in its 4th year of graduates, offers a fully distributed model of clinical veterinary education. Through partnership with first opinion veterinary practices around the country, final year students attend intramural rotations (IMR) in small groups (2 students), spending a minimum of 4 weeks within each species discipline. Discussion with partner practices has shown that this structured method of delivery of intramural rotations has had a wide reaching positive impact. The practice team, including vets and support staff, have shown greater engagement with students; and students have reported a more positive experience as a result. In order to deliver IMR, practices must provide a minimum of two ‘clinical instruction mentors’, who are trained in the principles of veterinary education and who are responsible for the students educational experience. As part of the IMR structure, students identify knowledge gaps and write learning objectives to guide their learning experience, whilst clinical instruction mentors provide a practice induction and provide weekly global feedback on student performance. Support staff are integral to the learning opportunity allowing students to gain experience within all aspects of the veterinary business. This workshop will provide an overview of the structure of the farm IMR at Surrey Vet School, highlighting the key components that lead to greater student engagement. We will endeavour to share the feedback from the clinical instruction mentors within Surreys farm partner practice network highlighting lessons learned from delivery of IMR which could be applied to enhance the farm EMS process. In particular, we will focus on the importance of giving timely feedback as well as tips and tricks for dealing with disengaged students. We would also like to use this workshop to better understand the challenges that farm practitioners are facing in regards to EMS in order to find solutions for driving positive change.

CATTLE PRACTICE VOLUME 31 PART 1 2023 40 Cattle Practice – What can poultry vets and calf vets learn from each other? Lock, J., Aplin, K., Cavill, B., Clark, M., Boehringer Ingelheim, Ellesfield Avenue, Bracknell, Berkshire, RG12 8YS It would be easy to think there are no similarities between broiler production and calf rearing but Boehringer Ingelheim poultry and cattle vets have found that the two industries have more in common than we initially realised. The overall aim of both is to rear a healthy animal to a good weight with optimal return on investment. In this discussion forum, the Boehringer Ingelheim cattle and poultry teams will look at how poultry vets work with their clients to improve health, welfare and productivity. Focusing on performance monitoring and disease control, we will discuss which practices might be applicable to the calf rearing setting, as well as looking at what pitfalls to avoid. We will be joined by a farmer with experience of rearing poultry and calves, who will give his perspective on how his approach to each sector has benefitted from knowledge of the other. The poultry industry is hugely focused on key performance indicators (KPIs), but what impact has this had? Antibiotic usage is a good example; it has been on a steep downward trajectory in the last ten years with 2021 antibiotic usage in broilers at 13.7mg/kg down by 72% from 2014 (VMD 2022) (data represents 90% of broiler chickens). The use of antibiotics in dairy herds is also thought to be declining but accurate data equivalent to that for broilers is not yet available. Data representing 9% of GB dairy herds showed a wide variation in antibiotic use, with the mean at 16.76mg/PCU (Kingshay 2022, VMD 2022). Broiler producers create and supply a plethora of data to the companies they grow for; weekly weights, daily, cumulative and final mortality, feed intake/food conversion ratios (FCR), environmental humidity, temperature, light levels, foot pad scores and much more. The data is used as a management tool for health and welfare, as well as to determine the appropriate timings to take the birds to slaughter and how much the farmer will be paid for the broilers they have produced. When data is used well, it can enable the farmer to make effective management decisions. The potential downside of collecting so much data is creating a ‘data rich but knowledge poor’ scenario. Large amounts of data can be overwhelming to analyse effectively, running the risk of missing important trends; for example, if weekly mortality is analysed then a spike in mortality across all farms at 8 days old could be missed if the cumulative mortality has dropped again by 14 days of age. From a veterinary health perspective, poultry vets will help farmers convert data into valuable knowledge and advise on all aspects of health, including drinker management, hygiene, lighting and feed management. Vaccination strategy is a key aspect of broiler health management. Broilers will receive a standard set of vaccinations irrespective of the farm’s health status; these are often given in the hatchery, before birds are moved to the rearing site. Other vaccines may be added depending on farm-specific risk. This strategy is based on the knowledge gained through long-term monitoring of KPIs, that proactive vaccination is more cost-effective than responding to a disease outbreak. Of course, health challenges such as Coccidia and Salmonella still appear in the broiler industry and KPI monitoring allows action to be taken quickly to minimise the impact – hygiene and biosecurity often being the key areas of focus. For example, an increase in Coccidia count is likely to trigger a hygiene review for the upcoming cleaning cycle – this will involve planning chemical usage with the farmer specifically for Coccidia control and monitoring the quality of the washing. Close monitoring of KPIs also enables the cost of any intervention, be that extra vaccination, medication, or management changes, to be weighed against the expected impact on production before implementation. Can some of these learnings from poultry be applied to calf rearing? What KPIs are important to calf rearers? For a KPI to be useful it must link to the goals and objectives of all involved - is it lowered antibiotic use, reduced age at first calving, quickest weight gain, or something else? Is a standard base-line vaccination strategy applicable to calf rearing? Could some of the hygiene and biosecurity protocols used for poultry housing and equipment be useful for calves? There is much that is good about calf rearing – what aspects of poultry farming would we want to avoid, and what could poultry vets learn from the cattle industry?

CATTLE PRACTICE VOLUME 31 PART 1 2023 41 The aim of this discussion forum is to explore these questions, share best practice across both sectors and pick up practical ideas to improve outcomes for calves. REFERENCES VMD (2022) UK Veterinary Antibiotic Resistance and Sales Surveillance Report UK-VARSS 20221. Available at: https:// assets.publishing.service.gov.uk/government/uploads/ system/uploads/attachment_data/file/1126450/FOR_ PUBLICATION_-_UK-VARSS_2021_Main_Report_Final_v3_- accessible.pdf Kingshay (2022) Dairy antimicrobial focus annual report. Available at: https://www.kingshay.com/news/kingshaysdairy-antimicrobial-focus-report-2021/

CATTLE PRACTICE VOLUME 31 PART 1 2023 42 Thoracic Ultrasound in Beef Suckler calves (BTUS) – Is it useful or even possible?! More, J.1 , Baxter-Smith, K.2 , 1 Solway Animal Health Consultancy, The Ben Sandside, Kirkcudbright, Dumfries and Galloway, DG6 4XD 2 MSD Animal Health, Walton Manor, Walton, Milton Keynes, MK7 7AJ INTRODUCTION Bovine respiratory disease (BRD) is a commonly reported cause of morbidity and mortality on UK beef suckler farms (Lorenz and others 2011, BaxterSmith and Simpson 2020, Hyde and others 2020, Thomson and others 2020). BRD is the result of a complex interaction of pathogens including viruses and bacterial agents. The initial insult is usually the result of viral infections such as bovine respiratory syncytial virus (BRSV) bovine herpes virus type 1 (BoHV-1), bovine parainfluenza-3 virus (BPI3V) and/ or bovine viral diarrhoea virus (BVDV). These viral infections predispose calves to secondary bacterial infections. Common pathogens associated with BRD include those mentioned above and Bovine coronavirus (BCoV), Bovine adenovirus-3 or 7 (BAV-3/7), Mannheimia haemolytica, Histophilus somni, Pasteurella multocida, Mycoplasma bovis and Streptococcus pnuemoniae, Mycoplasma dispar. Lung lesions due to BRD are associated with reductions in growth rates and productivity (Andrews 2000, Williams and Green 2007, Schneider and others 2009, Fernández and others 2020). Despite the importance of BRD, on-farm detection methods are currently limited. A systematic review and meta-analysis showed a Sensitivity (Se) of 27% based on clinical signs (Timsit 2016), demonstrating the difficulty of detecting BRD from clinical signs alone. The current ‘gold standard’ for the diagnosis of BRD in live calves is the Wisconsin Score Chart (McGuirk and Peek 2014), which has an increased accuracy (Se 62.4%, Specificity (Sp) 74.1%), however this requires daily examination, which is often not feasible in beef suckler calves (Buczinski and others 2015). Thoracic ultrasound (TUS) has been described as a fast, accurate, and practical calf-side diagnostic tool for assessing BRD prevalence and severity (Ollivett and Buczinski 2016). It is a sensitive and specific method for detecting BRD in dairy calves, with an Se of 76%–94% and Sp of 93%–100% (Buczinski and others 2016, Ollivett and Buczinski 2016). However, there is very limited previous work demonstrating the feasibility and accuracy of TUS in beef suckler calves (Cuevas-Gómez and others 2020). The main objective of this study was to demonstrate the feasibility and accuracy of using TUS to diagnose subclinical BRD in beef suckler calves. That is the practicalities of performing TUS in the field. A secondary objective was to compare TUS detection of BRD to farmer-reported treatment rates, to investigate the prevalence of undiagnosed or ‘subclinical’ BRD on Scottish beef suckler farms. MATERIALS AND METHODS The study was undertaken on eight beef suckler farms in Dumfries and Galloway, Scotland. Farms were selected as a convenience sample based on having a large population of calves of the correct age range (21–61 days old) to collect data from during the study period. TUS was scheduled to coincide with routine handling for other preventive actions. All calves were reared outdoors at grass with their dam. Calves were born outdoors at grass, except for a small number where assistance was required to deliver the calf, they were housed for no longer than 24 hours in individual bedded calving pens. One veterinary surgeon (JM) performed all examinations and was blinded to the treatment status of each calf prior to performing TUS. Examinations of the cohorts from the eight farms were conducted between March and June 2022. TUS was undertaken using an ‘EasyScan Go’ ultrasound scanner with linear probe (IMV Imaging, Bellshill, UK). The lung fields were scanned by moving the probe from a caudo-dorsal to cranio-ventral direction from rib spaces 10 to 6 on both sides, then each calf was given a TUS score on an 0–5 scale based on a standardised lesion identification and scoring system previously described (Buczinski and others 2015, Ollivett and Buczinski 2016). A normal TUS score was defined as ≤1 and abnormal scores as >1. The prevalence of abnormal TUS at farm level was calculated for each for each farm. Calf treatment data from the farm records were collected for analysis after scanning

CATTLE PRACTICE VOLUME 31 PART 1 2023 43 was performed. Treatments were classified as any antimicrobial product given to a calf by the farmer for perceived BRD prior to TUS examination. Farmers identified calves for treatment based on observation of clinical signs. RESULTS A total of 204 TUS examinations were performed by a single veterinarian over eight herds during the data collection period. Although TUS examinations use the same protocols as used when scanning dairy calves additional challenges are present. • Scheduling: Organising scanning of dairy calves is simple as they are housed, when sampling groups of suckler calves it is best to fit in with a routine handling by the farmer for another reason e.g., Clostridial vaccine. • Restraint: Calves are separated from dam as a safety concern. Smaller calves can be handled by loose restraint in crush or race in groups of 2-4. Larger calves, possibly 35 days old +, are best restrained in head yolks. • Scanning positioning: Due to limitations of space we found that rather than kneeling beside the calf it was better to stand and reach down from above from the opposite side being scanned. • Anatomy: Scanning fields remain the same however, scanning the apical lobes on the right was more challenging due to the increased muscle mass especially in older calves. However, reaching down from above reduced this problem. • Transducing agent: Due to increase thickness of coats in some calves larger volumes of Isopropyl Alcohol are required to saturate the exam area (50-60mls). Of the 204 ultrasonographic examinations, 62 (32%) were classified as abnormal and 138 (68%) as normal. The percentage of abnormal ultrasound examinations on farms ranged from 16.7% to 53.6%. All animals scoring 3 and above at the time of scanning were clinically examined. All were febrile with dyspnoea and spontaneous coughing. These were treated using antibiotic and non-steroidal anti-inflammatory. 11 Animals were treated in total. No calves were treated for BRD by farmers (Table 1 and Figure 1). DISCUSSION BTUS is more challenging than TUS carried out in dairy calves. It requires greater initial engagement with farmers as they must give some advance Table 1. Descriptive summary of the number of calves with an abnormal thoracic ultrasound (TUS) examination. FARM ID TUS Examinations Abnormal TUS examinations Abnormal TUS % A 32 9 28.1 B 35 12 43.3 C 28 15 56 D 9 4 44.4 E 26 11 42.3 F 20 4 20 G 24 6 25 H 30 5 16.7 Figure 1. warning of routine handling to coordinate TUS at the same time. Physical restraint of calves not handled or subjected to close human presence requires additional measures either head restraint for larger calves or simple penning in a narrow race for smaller calves. Increased muscling makes access to apical lobes on the right side of the chest more challenging but can be overcome be a dorsal approach i.e., reaching down from above when standing on the left side. And finally, beef calves have increased thickness of coats, as a result larger volumes of transducing agent/Isopropyl Alcohol are required to saturate the exam area. Throughout all farms, 32% of calves were identified by TUS examination as being abnormal; however, none of these had been identified and treated by the farmer. This suggests that BRD detection by farmers is currently very low, or frequently, non-existent, and that TUS has the potential to identify farms with poor detection rates. TUS examination at herd level might provide practitioners with the ability to identify farms with

CATTLE PRACTICE VOLUME 31 PART 1 2023 44 poorer sensitivity and specificity of BRD detection. This could benefit the farm by highlighting suboptimal BRD detection rates and allowing the vet and farmer to work on an improvement strategy. Second, demonstrating to farmers the true prevalence of calf subclinical respiratory disease (and subsequent welfare and financial implications) could provoke a discussion about preventive healthcare strategies, such as vaccination, environment and colostrum management. Any additional tools that allow a greater interaction between vet and beef suckler units, which are traditionally less engaged with vet practices (Baxter-Smith and Simpson 2020) are likely to improve the welfare and sustainability of the enterprise, while adding additional income streams for practices that do not depend solely on medicine sales. CONCLUSION This small pilot study indicates that Thoracic Ultrasound in Beef Suckler calves (BTUS) – Is useful and possible. Furthermore farmers are underdiagnosing BRD in their beef suckler cattle youngstock. Use of TUS on UK beef suckler farms may increase detection rates and help identify farms where diagnosis of BRD is inaccurate. Demonstrating the ‘true’ impact of BRD on farm may be of value in demonstrating the need to implement preventive healthcare strategies. BTUS can also be a way for veterinarians to engage more closely with their beef suckler clients and subsequently improve suckler calf health and welfare. REFERENCES Andrews, A.H. (2000) Calf pneumonia costs! Cattle Pract. 8(2): 109–14 Baxter-Smith, K., Simpson, R. (2020) Insights into UK farmers’ attitudes towards cattle youngstock rearing and disease. Livestock. 25(6): 274–81 Buczinski, S., Menard, J., Timsit, E. (2016) Incremental value (Bayesian Framework) of thoracic ultrasonography over thoracic auscultation for diagnosis of bronchopneumonia in preweaned dairy calves. J. Vet. Intern. Med. 30(4): 1396–401 Buczinski, S.L., Ollivett, T., Dendukuri, N. (2015) Bayesian estimation of the accuracy of the calf respiratory scoring chart and ultrasonography for the diagnosis of bovine respiratory disease in pre-weaned dairy calves. Prev. Vet. Med. 119(3–4): 227–31 Cuevas-Gómez, I., McGee, M., McCabe, M., Cormican, P., O'Riordan, E., McDaneld, T., Earley, B. (2020) Growth performance and hematological changes of weaned beef calves diagnosed with respiratory disease using respiratory scoring and thoracic ultrasonography. J. Anim. Sci. 98(11): skaa345. doi: 10.1093/jas/skaa345. PMID: 33095858; PMCID: PMC7694598. Fernández, M., Ferreras, M.D.C., Giráldez, F.J., Benavides, J., Pérez, V. (2020) Production Significance of Bovine Respiratory Disease Lesions in Slaughtered Beef Cattle. Animals (Basel). 10(10): 1770. doi: 10.3390/ani10101770. PMID: 33007901; PMCID: PMC7599887. Hyde, R.M., Green, M.J., Sherwin, V.E., Hudson, C., Gibbons, J., Forshaw, T., Vickers, M., Down, P.M. (2020) Quantitative analysis of calf mortality in Great Britain. Journal of Dairy Science 103(3): Lorenz, I., Earley, B., Gilmore, J., Hogan, I., Kennedy, E., More, S.J. (2011) Calf health from birth to weaning. III. housing and management of calf pneumonia. Ir. Vet. J. 64(1): 14. doi: 10.1186/2046-0481-64-14. PMID: 22018053; PMCID: PMC3220626. McGuirk, S.M., Peek, S.F. (2014) Timely diagnosis of dairy calf respiratory disease using a standardized scoring system. Anim. Health Res. Rev. 15(2): 145–7 Ollivett, T.L., Buczinski, S. (2016) On-farm use of ultrasonography for bovine respiratory disease. Vet. Clin. North Am. Food Anim. Pract. 32(1): 19–35 Schneider, M.J., Tait, R.G. Jr., Busby, W.D., Reecy, J.M. (2009) An evaluation of bovine respiratory disease complex in feedlot cattle: Impact on performance and carcass traits using treatment records and lung lesion scores. J. Anim. Sci. 87(5): 1821-7. doi: 10.2527/jas.2008-1283. Epub 2009 Jan 30. PMID: 19181770. Thomson, S., Spencer, M., Reeves, A., Moxey, A. (2020) (Pareto Consulting) SRUC Factsheet Structure and Efficiency of the Scottish Beef Herd - Cattle Tracing System Insights November 2020 Timsit, E. (2016) Diagnostic accuracy of clinical illness for bovine respiratory disease (BRD) diagnosis in beef cattle placed in feedlots: a systematic literature review and hierarchical Bayesian latent-class meta-analysis. Prev. Vet. Med. 135: 67–73 Williams, P., Green, L.E. (2007) Associations between lung lesions and grade and estimated daily live weight gain in bull beef at slaughter. Published in: Cattle Practice 15(3): 244-249. ISSN 0969-1251