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ForewordThis document was commissioned to provide UK veterinary surgeons with up-to-date information on Streptococcus equiinfection and to provide practical recommendations for veterinary surgeons in the field. The participants were selected to provide representation from a range of expertise and viewpoints and included practitioners, academics and social scientists. The document and practical recommendations were developed using a modified non-anonymised two-round Delphi process, considering published and unpublished research relating to ‘strangles’ using online discussion. The expert group was convened by UK-Vet Equineand Redwings and an online meeting held on 20th January 2021 with sponsorship from MSD and support from World Horse Welfare. The sponsors did not participate in the meeting and had no influence over editorial content. Each of the panellists was provided with a sub-topic and presented a review of the evidence pertaining to that area prior to taking two rounds of questions relating to the evidence presented. Where research evidence was conflicting or absent, collective expert opinion, based on the experience of the group, was applied. The opinions expressed are the consensus of views expressed by the authors who all approved the final manuscript. Where it was not possible to reach consensus, different viewpoints are presented.

Autumn is traditionally a time when most horses are de-wormed with one or more products that are effective against tapeworms and both adult and larval roundworms. However, the increasing prevalence of resistance and availability of diagnostics should prompt scrutiny of whether blanket de-worming at this time of year is appropriate. If management is good and horses are at low-risk of clinical disease, then there may be no need to use anthelmintics. Serology provides a means of assessing exposure to both cyathostomins and tapeworms, but it has its limitations and does not provide a validated means of assessing the risk of parasitic disease. The results of serology, results of faecal worm egg counts performed in the population through the preceding grazing season, and knowledge of management practices in the population should all be considered when assessing whether the risk of the disease to the individual is such that it must take priority over the ever-increasing threat of resistance in the equine population.

The veterinary profession's use of critically important antimicrobials is a One Health issue that has come under the scrutiny of the World Health Organization and the European Parliament. Failure by the veterinary profession to demonstrate the ability to self-regulate may result in restriction on the freedom to dispense antimicrobials, in an effort to protect human health. The implementation of such legislation would have a considerable impact on veterinary practices and would likely impair our ability to treat some conditions. These concerns, and the increasing frequency of multi-resistant bacterial infections in equine patients, should prompt implementation and audit of antimicrobial stewardship practices and measures to limit the development and spread of multi-resistant bacteria.

ForewordThis document was commissioned to provide veterinary surgeons with up-to-date information on equine influenza (EI) and the situation that has developed through 2019. The content of the document and practical recommendations were developed using an informal modified two-round Delphi process, considering published and unpublished research relating to EI using a roundtable forum and online discussion. Where research evidence was conflicting or absent, collective expert opinion, based on the experience of the group, was applied. The opinions expressed are the consensus of views expressed by the authors who all approved the final manuscript. Where an agreement was not reached, opposing views are presented such that readers can understand the arguments. The expert group was organised by UK-Vet Equineand the meeting held at Stanstead Airport on 11 July 2019 with sponsorship from MSD. The sponsors did not participate in the meeting and had no input to or sight of the resultant manuscript prior to publication.

ForewordThere are nine different equid herpesviruses (EHVs). Five types (EHV-1 to EHV-5) infect the domestic horse, while EHV-6 to EHV-9 are associated with infections in wild equids including asses and zebra. This review focuses on the commonest and most important clinical pathogens, the alphaherpesviruses EHV-1 and 4. These are respiratory pathogens and are also responsible for abortion and neurological disease. Several aspects of the biology of these viruses makes their control challenging. In particular, latent infection and reactivation of infection under stress, with subsequent virus shedding, makes elimination of these viruses impossible. Biosecurity measures are important both for minimising the risk of an outbreak and for controlling any outbreak when it occurs. Recognition of the disease and confirmatory diagnosis are also important in order for appropriate biosecurity measures to be instigated. Vaccination in key demographic groups is also important to reduce severe clinical disease. Unfortunately many horse owners are unaware of EHV or the importance of biosecurity measures and vaccination for control.

An unexpected side effect of the lockdown to reduce the spread of COVID-19 in humans is a reduced level of exercise for horses. David Rendle emphasises the importance of weight management and the need to prepare for this now to allow safe, stable weight loss over the winter.

Despite increasing awareness within the veterinary profession and equine industry of the potential implications of anthelmintic resistance (AHR), there is a concern that insufficient measures are being taken to reduce its development and spread. This document was commissioned to provide veterinary surgeons with up to date information on worm control plans that will prevent clinical disease while minimising selection pressure for resistance. Recommendations were developed using an informal two-round Delphi process, considering published and unpublished research relating to equine parasite control using a roundtable forum and online discussion. Where research evidence was conflicting or absent, collective expert opinion, based on the experience of the group, was applied. The opinions expressed are the consensus of views expressed by the authors. Where agreement was not reached opposing views are presented such that readers can understand the arguments. The document is focused on the management of horses and ponies; while much of the information herein applies to donkeys, it is important to recognise that donkeys face major challenges with AHR, and further research is required before specific recommendations can be made with respect to this species. The expert group was organised by UK-Vet Equineand hosted by Moredun Research Institute with sponsorship from Virbac and additional support from The Horse Trust and vetPartners.

Equine practices cannot fail to be aware of the need to implement sustainable parasite control strategies, yet engagement with practice-led targeted worming plans remains poor and many owners persist with interval dosing strategies or they administer anthelmintics in a haphazard manner. Veterinary practices should be in a position to be able to offer a better service to their clients than any other provider, if they have the motivation to do so. Practices that do use worming plans to their advantage can see benefits from increased anthelmintic and laboratory test sales, improved uptake of other packaged services and greater client engagement with the practice.

ForewordEquine obesity is now so common that is has become accepted by many as the norm (Owers and Chubbock, 2012). Rates of obesity may be as high as 70% in some populations and obesity is often associated with morbidities that may ultimately result in mortality. Obesity is a common feature in animals diagnosed with equine metabolic syndrome, a conflation of metabolic disturbances including insulin dysregulation, which may lead to laminitis. Obesity is a risk factor for insulin dysregulation and is therefore implicated in laminitis risk. In addition to laminitis, adverse consequences of obesity include orthopaedic disease, hyperlipaemia, hyperthermia, infertility and poor performance. Over time, perception of what constitutes a healthy body condition in horses has shifted, with the result that potentially harmful excess adiposity may not be recognised by owners or those working in the equine industry (Owers and Chubbock, 2012). In addition, increasing numbers of equines are kept as companions rather than athletes and live relatively inactive lifestyles favouring the development of obesity. Finally, owners of leisure horses often think their horses are working hard when, in reality, their exertions have minimal impact on their energy requirements.Despite increasing awareness within the veterinary profession and equine industry of the impact of obesity on equine welfare, little progress seems to have been made in tackling it. This document was commissioned in order to provide veterinary surgeons with up-to-date information on equine obesity and to equip them to tackle it within their own practices. Recommendations were developed using an informal two-round Delphi process, considering published and unpublished research relating to equine obesity using a round table forum and online discussion. Where research evidence was conflicting or absent, collective expert opinion based on the clinical experience of the group was applied. The opinions expressed are the consensus of views expressed by the authors. Where agreement was not reached, opposing views are presented such that readers can understand the arguments fully. The document is focused on the management of horses and ponies; while much of the information herein is applicable to donkeys it is important to recognise that the metabolism and management of donkeys are different and further research is required before specific recommendations can be made. The expert group was organised by UK-Vet Equinewith sponsorship from Baileys Horse Feeds.

ForewordThe European College of Equine Internal Medicine (ECEIM) consensus statement recently made the distinction between disease of the squamous mucosa (Equine Squamous Gastric Disease; ESGD) and of the glandular mucosa (Equine Glandular Gastric Disease; EGGD) (Sykes et al, 2015a). Since its publication, a number of reports have furthered understanding of the pathology and management of EGGD, such that new clinical guidelines for the management of this condition were considered necessary. The following guidelines are the consensus views of subject specialist representing authors of the ECEIM consensus statement, authors of recent clinical research, and clinical specialists active in the management of horses with this condition.The recommendations were developed using an informal two-round Delphi process, considering published and unpublished research relating to EGGD using a round table forum and online discussion. Where research evidence was conflicting or absent, collective expert opinion based on the clinical experience of the group was applied. The opinions expressed are the consensus of views expressed by the authors. The expert group was organised by UK-Vet Equinewith sponsorship from Luoda Pharma.

Cellulitis is a common condition in equine practice and one that is frustrating to treat. Typically, antimicrobials and anti-inflammatories are administered and most cases resolve with time. Bacterial culture and susceptibility should be performed more frequently as they enable more responsible and informed decisions on antimicrobial choice to be made, especially when first ineffective. In cases that are refractory to initial treatment imaging modalities play a role in providing a better understanding of the extent of the underlying pathology and hence prognosis. Recurrence is common.

Autumn is traditionally a time when all horses are de-wormed with a product that is effective against tapeworms and both adult and larval roundworms. However, if management is good and appropriate testing has been performed for the presence of round and tapeworms, there may be no need to use anthelmintics. For tapeworms, a single test for antibodies to Anoplocephalaspp.provides reassurance that treatment is not necessary. For roundworms the situation is more complicated as there is no test for larval stages currently. There is therefore a reliance on repeated worm egg counts through the grazing season. The risk of exposure, albeit low, to large strongyles also needs to be considered.

Equine metabolic syndrome (EMS) and/or pituitary pars intermedia dysfunction (PPID) are identified in most horses with laminitis. In some cases of laminitis, a diagnosis of EMS or PPID is obvious from clinical signs but in others laboratory testing can be helpful to confirm the diagnosis, assess laminitis risk and monitor treatment responses. Laboratory methods for assessing PPID and EMS have their limitations but recent clinical research from a number of groups has resulted in advances — this article aims to summarise recent developments and how they can be applied in practice.

Atypical myopathy, or perhaps more correctly hypoglycin toxicity, is a distressing condition that is associated with a high fatality rate. The onset of signs can be dramatic or more insidious and a range of clinical signs related to muscle weakness develop. Outbreaks are common and a clinical case should prompt blood testing of cohorts to check for subclinical cases that may go on to develop signs. A suggested protocol for managing clinical cases and in-contacts is outlined. Horses with clinical signs should ideally be hospitalised to somewhere that they can receive 24-hour care and multimodal analgesia. Even cases which appear mild often deteriorate before they improve and it is therefore prudent to transport while they are standing and mobile. Prognosis is exceedingly hard to predict.

Equine veterinary surgeons are so familiar with influenza vaccination that there is perhaps a tendency to take the disease for granted. However, the Australian outbreak in 2007 highlighted the devastating effect that the virus can have on equine welfare and equine industries, albeit in a naïve population. The outbreak, which resulted from the import of vaccinated horses that were infected and shedding virus, was estimated to have cost Australia around $1 billion dollars. However, vaccination using contemporary virus strains was also an important part of the solution. Given the frequency of horse movements into, and within, the UK equine population, in which it is estimated from sales data that only one in three horses are vaccinated, the threat of a major equine influenza (EI) outbreak in the UK is ever present. At practice level vaccines need to be chosen carefully and protocols ought to be in place to ensure that horses exhibiting clinical signs consistent with EI are isolated effectively and diagnosed promptly.

Despite extensive research in recent years into the aetiopathogenesis of sweet itch (more appropriately termed insect bite hypersensitivity or IBH) there have been no revelations in options for treatment. Where new treatments have become available they have not been supported by published evidence of efficacy leaving clinicians uncertain as to their relative merits. The absence of universally effective treatments has left the door open for a plethora of products to line the tack shop shelves frequently leaving the veterinary profession side-lined when it comes to managing the condition. This is regrettable as advice on effective management and avoidance strategies is likely to be infinitely more valuable than any treatments employed after clinical signs have developed.

Resistance to all of the licensed classes of anthelmintics is now widespread and targeted worming strategies are advocated to reduce selection pressure and delay the onset of anthelmintic resistance. Targeted strategies of worm control are relatively straightforward in adult horses but where youngstock are present the situation becomes more complicated. Youngstock are more susceptible to infection and clinical disease and additional parasites have to be considered in control programmes. Despite the additional complexity, targeted worming strategies can be employed on breeding establishments, and indeed should be, as owners of young horses have the most to lose if anthelmintic resistance develops.

Most horse owners worm their horses inappropriately and rarely consult veterinary surgeons. The majority perform a form of interval dosing regardless of need, increasing selection pressure for anthelmintic resistance. Targeted worming programmes should be adopted and individually tailored to all populations of adult horses to delay the onset of resistance. When instigating targeted worming regimens the use of faecal egg count reduction tests (FECRT) should be strongly encouraged; they are simple and inexpensive. Targeted strategies are cheaper for horse owners and provide an opportunity for veterinary surgeons to engage with, and profit from, preventive health care. As a profession, veterinary surgeons are better placed to implement effective strategies that are tailored to individual animals than other providers. Currently those owners that do choose to use faecal egg counts (FEC) and targeted worming plans frequently depend on online providers when they could be better served by their veterinary surgeons who have more direct involvement in the management of the property and general health care of individual horses.

While our understanding of pituitary pars intermedia dysfunction (PPID) remains limited a great deal of progress has been made recently in diagnosis and management of the condition. The disease should be considered in all but the youngest horses with laminitis and endocrine testing should be performed. Measurement of adrenocorticotropic hormone (ACTH) and insulin concentrations are recommended and a follow-up thyrotropin-releasing hormone (TRH) stimulation test should be performed if borderline ACTH results are obtained. Pergolide is the only licensed treatment for the condition and the only treatment that is likely to be effective. Horses that are being treated should be monitored clinically and endocrinologically every few months as response to treatment between individuals is variable. The importance of appropriate nutrition and good preventive medicine in horses with PPID cannot be overemphasised.

The following report describes the investigation of weight loss and abortion in a Thoroughbred broodmare. The mare was identified to have systolic and diastolic heart murmurs and haematological and clinical chemical examinations revealed a marked inflammatory response. The mare was subsequently diagnosed with bacterial endocarditis affecting both the mitral and aortic valves and was subjected to euthanasia in view of the hopeless prognosis. The characteristic clinical and pathological findings of bacterial endocarditis are discussed.

The following report describes an unusual case of poor performance. The findings of clinical examination were unremarkable in a 16 year-old gelding, however neutropaenia and anaemia were identified on haematological examination. A bone marrow disorder was suspected and ultimately confirmed. The investigation of anaemia in horses is discussed with reference to this unusual case.

Respiratory tract sampling is a vital component of the diagnosis of lower respiratory tract disease. The following report describes the clinical findings and response to treatment in two cases of lower respiratory tract disease where diagnosis was based upon the results of laboratory analysis of tracheal wash and bronchoalveolar lavage samples.

Sampling of fluids from the equine respiratory tract has become routine in equine practice and is an important component in the diagnosis of respiratory disease. Whilst the procedures are relatively straightforward, interpretation of the results may not be! A great deal remains to be determined about the relationships between the results of laboratory analyses and respiratory health and disease. The following article aims to give some tips on maximising the value of respiratory tract samples, focusing on sampling from the lower airways.

Sampling of fluids from the equine respiratory tract has become routine in equine practice and is an important component in the diagnosis of respiratory disease. Whilst the procedures are relatively straightforward, interpretation of the results may not be! A great deal remains to be determined about the relationships between the results of laboratory analyses and respiratory health and disease. The following article aims to give some tips on maximising the value of respiratory tract samples, focusing on sampling from the lower airways.

Haematology and biochemistry are frequently used to assess horses' fitness to compete and, in the event of disappointment, to investigate potential explanations for under-performance (Figs. 1 - 3). Despite the perceived importance of clinical pathology in these animals the evidence to substantiate the value of specific tests of fitness in resting horses is lacking. In addition to assessing measures of fitness directly, clinical pathology has a role in eliminating the presence of infectious challenge or other disease that may have a significant effect on performance. The role of haematological and clinical chemical examinations and relevance of specific findings are discussed.

Acts of terrorism, an increase in the use of firearms, drug abuse, the use of so-called date-rape drugs, and driving whilst under the influence of drugs, are just some of the subjects frequently in the news. In the absence of fingermarks and of material leading to the recovery of DNA, the forensic scientist has to rely upon chemical analysis of trace amounts of materials including explosives, drugs, toxicological specimens, firearms discharge residues, fibres, glass, paint, soil etc., in order to establish or eliminate links between suspect and victim andor scene. This tutorial reviewdescribes analytical problems facing the forensic chemist, and the current methods and techniques employed to tackle them.

Crystals of the 3,5-dimethylpyrazolylgallium dimethyl dimer [Me2Ga·N2C5H7]2(1a) are monoclinic, a = 8.660(3), b = 13.776(1), c = 8.443(2) Å, β = 112.45(2)°, Z = 2, space group P21/c, and crystals of the hydroxy-bridged species [Me2Ga(OH)(N2C5H7)GaMe2·2N2C5H8] (1b) are monoclinic, a = 28.778(3), b = 9.098(3), c = 20.222(2) Å, β = 100.72(1)°, Z = 8, space group C2/c. Both structures were solved by Patterson and Fourier methods and were refined by full-matrix least-squares methods to final Rvalues of 0.071 and 0.045 for 1443 and 2746 reflections with I ≥ 3σ(I) respectively. Molecules of 1alie on crystallographic centers of symmetry, the central Ga—(N—N)2—Ga ring being almost planar as a result of steric interactions between gallium-methyl groups and those on the 'pyrazolyl' rings. The mean Ga—N and Ga—C distances are 1.993 Å and 1.962 Å respectively. Compound 1bwas formed by the attack of moisture on the strained dimer 1a. The central feature is a five-membered Ga2N2O ring, with two 3,5-dimethylpyrazoie molecules hydrogen-bonded to it (N—H … O, O—H … N, 2.851 and 2.892 Å) and to each other (N—H … N, 2.907 Å). The five-membered ring adopts a slightly distorted envelope conformation, the angle between the Ga2N2and N2O moieties being 13.9°. The mean Ga—N and Ga—O distances are 1.989 and 1.934 Å respectively.

Crystals of the pyrazolylgallium dimethyl dimer (1a) are monoclinic, a = 16.914(3), b = 21.747(6), c = 8.117(2) Å, β = 92.09(3)°, Z = 8, space group P21/c, those of the 3-methyl-pyrazolylgallium dimethyl dimer (1b) are also monoclinic, a = 13.473(6), b = 7.162(2), c = 18.468(4) Å, β = 113.78(2)°, Z = 4, space group P21/c, and those of the indazolylgallium dimethyl dimer (1c) are orthorhombic, a = 8.909(2), b = 27.463(3), c = 15.738(2) Å, Z = 8, space group Pbca. All three structures were solved by Patterson and Fourier methods and were refined by full-matrix least-squares methods to final Rvalues of 0.065, 0.061, and 0.036 for 2542, 2011, and 1986 reflections with I ≥ 3σ(I) respectively. The three crystal structure analyses emphasize the critical role of steric interaction in determining the molecular geometry for these molecules. The results clearly demonstrate that changing deuterium for methyl groups on the gallium atoms and introducing substituents on the bridging 'pyrazolyl' ligands in the [D2Ga·N2C3H3]2dimer cause a pronounced flattening of the central Ga—(N—N)2—Ga boat conformation and a noticeable lengthening of the Ga—N bonds. Average Ga—N distances are 1.996, 1.986,1.996 Å, and V-angles (the angle between the Ga2N2C3moieties) are 131.5,139.5, and 147.8° in 1a, 1b, and 1crespectively.

Retained testicles and granulosa cell tumours may be suspected, or even diagnosed, from a history and clinical examinations. However, endocrine assessment is typically required to confirm the diagnosis and provide greater confidence of clinical findings prior to surgical excision of the affected gonad being performed. Anti-Müllerian hormone provides a convenient, reliable and cost-effective option for diagnosing both conditions. The following article discusses the use of this new assay.

Bronchoalveolar lavage (BAL) is an under-utilised procedure in the investigation of equine respiratory disease. It provides information on lower airway inflammation that cannot be obtained from a tracheal aspirate. In the diagnosis of Recurrent Airway Obstruction, Summer Pasture-Associated Recurrent Airway Obstruction and Inflammatory Airway Disease it provides more reliable cytological inflammation than a tracheal aspirate. The procedure is safe, straightforward and inexpensive to perform.

Introduction:this edition of the Equine Review has a focus on strangles, looking at serological testing, the possibility of an insect vector, issues of contamination of equipment used for diagnosis and the effect of penicillin on the immune response.