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Summary: Critical appraisal skills enabling assessment of the validity and importance of evidence are essential for clinicians to make informed decisions regarding what new information should be incorporated into their clinical practice. This review highlights key points to consider in a critical review concentrating on common study designs used in the equine literature. [ABSTRACT FROM AUTHOR]

Summary: Background: Despite the regularity with which castration is performed, the types of complications and current best practice are unknown. Objectives: The objective of this study was to perform a prospective audit of routine equine castrations performed in general practice to determine complication rates and factors associated with them. Study design: Multicentre, prospective audit of castrations. Methods: Data on castrations were collected on the day of surgery from 18 veterinary practices; 30‐days post‐operatively follow‐up was obtained and complications recorded. Frequency of complications was reported, and multilevel, multivariable logistic regression models used to investigate factors associated with the most common complications of bleeding in the first 24 h, stiffness of gait and/or swelling and discharge and/or infection. Results: Data were collected on 495 castrations performed by 53 participating veterinary surgeons. Over two thirds of surgeries were performed outside, 21% were performed under standing sedation and 79% with the horse recumbent. Almost all (98 and 97%) patients received preoperative nonsteroidal anti‐inflammatories (NSAIDs) and antimicrobials, respectively. One or more intraoperative complications were reported in 14.5% of procedures; most common were bleeding and excessive movement. Follow‐up to 30 days was available for 392 equids. One or more complications were reported in 44 castrations (11.2%). Swelling was the most common, then infection and stiffness of gait. Serious complications were rare. Main limitations: It is possible that there was bias towards submission of data for procedures where complications occurred. The low complication rates reduced the power to determine factors associated with complications. Minor complications may go unreported by owners and may be underrepresented. Conclusions: Overall complications associated with castration are low and mortality rare. Findings from this study can be used as guidelines for practices to perform regular audit to determine if their negative outcomes are comparable or warrant further investigation. [ABSTRACT FROM AUTHOR]

Summary: Background: Previous studies suggest that ocular disease is common among aged horses but owners may fail to identify or underestimate their clinical relevance. Objectives: To document the prevalence of owner‐reported ocular disease in horses aged ≥15 years. In a subset of these horses, to document ophthalmic findings from veterinary examination and compare with owner‐reported ocular disease, and to determine risk factors for veterinary ophthalmic findings. Study design: Cross‐sectional study. Methods: Owners of aged horses completed a survey on management, clinical signs and medical history. Risk factors for the presence of ocular disease as reported by the owner were determined. A subset of these horses underwent an ophthalmological examination. Risk factors for the presence of ocular disease detected during this examination were determined. Agreement between owner‐reported data and veterinary ophthalmic findings was assessed. Results: Abnormal ocular findings were detected in 287/327 horses aged ≥15 years that underwent a complete ophthalmic examination, whereas the presence of ocular disease as reported by the horse‐owners was only 3.3%. Agreement between owner‐reported ocular disease and results of the veterinary examination was low for all categories analysed. An owner‐reported history of ocular discharge was associated with increased odds of veterinary‐reported diminished vision. Increasing age was associated with increased odds of the presence of an eye abnormality (any) and cataracts. Appaloosa horses had increased odds of cataract compared with other breeds. Horses in work were less likely to have an eye abnormality. Main limitations: Volunteer bias may have influenced our results with owners of sick horses or those more concerned about their horses more likely to volunteer at the initial recruitment phase. Conclusions: This study showed a high prevalence of ocular lesions in aged horses which was not reflected in owner‐reported disease. This has highlighted problems in obtaining information on ocular conditions from horse‐owners. [ABSTRACT FROM AUTHOR]

Summary: Background: Pathogens are frequently implicated in equine respiratory disease. In Ethiopia, respiratory disease is a frequent cause for presentation at veterinary clinics and a priority concern for users of working horses. However, there is little existing literature on possible aetiologies. Objectives: Determine prevalence of respiratory signs and exposure to major respiratory pathogens through a serological survey. Study design: Cross‐sectional. Methods: Systematically selected horses from 19 sites in central Ethiopia were examined clinically and sampled once (August‐December 2013). A face‐to‐face interview collected data on horses’ management and history. Serological testing targeted equine influenza virus (EIV), equine herpesviruses‐1 (EHV‐1) and ‐4 (EHV‐4), equine rhinitis viruses A (ERAV) and B (ERBV), equine arteritis virus (EAV) and Streptococcus equi subspecies equi (S. equi). Results: Owners reported a recent history of coughing in 38% of horses and nasal discharge in 7%. No animals were observed coughing during examination but 6% had a nasal discharge. Antibodies towards S. equi, were most prevalent (8%, 33/350). Antibodies to EAV were confirmed in one animal (0.3%). Low antibody titres to EHV‐1/4 and ERA/BV suggested prior exposure but antibodies to EIV were not detected. Multivariable, multilevel logistic regression analysis for risk factors associated with S. equi serostatus showed higher odds of seropositivity in younger animals and those working less frequently. Main limitations: A single serological sample cannot describe dynamic changes in antibodies. Sampling horses at the place of work may result in healthy‐worker bias. Conclusions: S. equi may be endemic in this population and contributing, in part, to the occurrence of respiratory disease. Low prevalence of antibodies to viruses, with the exception of EIV, indicates these pathogens are present, but unlikely a predominant cause of respiratory signs and noninfectious causes of disease should also be investigated. Working horses in this region would be vulnerable to incursion of equine influenza. [ABSTRACT FROM AUTHOR]

Summary: Background: Evaluation of coagulation status is an important component of critical care. Ongoing monitoring of coagulation status in hospitalised horses has previously been via serial venipuncture due to concerns that sampling directly from the intravenous catheter (IVC) may alter the accuracy of the results. Adverse effects such as patient anxiety and trauma to the sampled vessel could be avoided by the use of an indwelling IVC for repeat blood sampling. Objectives: To compare coagulation parameters from blood obtained by jugular venipuncture with IVC sampling in critically ill horses. Study design: Prospective observational study. Methods: A single set of paired blood samples were obtained from horses (n = 55) admitted to an intensive care unit by direct jugular venipuncture and, following removal of a presample, via an indwelling IVC. The following coagulation parameters were measured on venipuncture and IVC samples: whole blood prothrombin time (PT), fresh plasma PT and activated partial thromboplastin time (aPTT) and stored plasma antithrombin activity (AT) and fibrinogen concentration. D‐dimer concentration was also measured in some horses (n = 22). Comparison of venipuncture and IVC results was performed using Lin's concordance correlation coefficient. Agreement between paired results was assessed using Bland Altman analysis. Results: Correlation was substantial and agreement was good between sample methods for all parameters except AT and D‐dimers. Main limitations: Each coagulation parameter was tested using only one assay. Sampling was limited to a convenience sample and timing of sample collection was not standardised in relation to when the catheter was flushed with heparinised saline. Conclusions: With the exception of AT and D‐dimers, coagulation parameters measured on blood samples obtained via an IVC have clinically equivalent values to those obtained by jugular venipuncture. [ABSTRACT FROM AUTHOR]

Background Equine recurrent uveitis ( ERU) is a common cause of ocular pain and blindness in horses. Leptospira spp. have been commonly implicated in the pathophysiology of ERU in mainland Europe and the USA. No recent studies have been carried out in the UK, but Leptospira is reported not to be a major factor in the aetiology of ERU in the UK. Objectives To establish the prevalence of Leptospira-associated ERU in the UK and to identify the serovars involved in these cases; to compare serum vs. aqueous humour antibody levels in cases and controls in order to confirm the diagnosis of Leptospira-associated ERU, and to assess the usefulness of serology alone as a confirmatory test for Leptospira-associated ERU in the UK. Study design Case-control study. Methods Eyes enucleated for clinical reasons in ERU-affected horses were collected. Blood and aqueous humour were obtained to determine antibody levels against a variety of Leptospira serovars and C-values (aqueous humour value/serum value) were calculated. In addition, eyes, blood and aqueous humour were obtained from control cases for comparison. Histopathology was performed in all eyes to confirm uveitis in each case. Differences in seroprevalences between ERU and control cases and between Leptospira- and non- Leptospira-associated ERU cases were calculated. Results A total of 30 ERU and 43 control eyes were analysed. Of the ERU eyes, only two had a C-value of >4 (prevalence of Leptospira-associated uveitis: 6.7%). Serovars hardjo and javanica were detected. There was no difference in seroprevalence between horses with uveitis and control cases (65.5% and 41.9%, respectively; P = 0.11) or between Leptospira- and non- Leptospira-associated uveitis cases (100% and 63.0%, respectively; P = 0.52). Main limitations The study was limited by low case numbers. Eyes were presented at different stages of disease. The only test used to detect Leptospira was the microscopic agglutination test. Conclusions Leptospira-associated ERU is uncommon in the UK. Serology alone may not help to definitively diagnose Leptospira-associated uveitis in this country. [ABSTRACT FROM AUTHOR]

Reasons for performing study Working horses, donkeys and mules suffer from numerous diseases and clinical problems. However, there is little information on what owners perceive as important health concerns in their working animals. Objectives To identify and prioritise with owners the diseases and other health concerns in working equids in central Ethiopia using participatory methodologies. Study design Participatory situation analysis (PSA). Methods The study was conducted with carthorse- and donkey-owners in 16 sites in central Ethiopia. Multiple participatory methodologies were utilised, including ranking, matrices and focus group discussions. Owners' perceptions on frequency, importance, morbidity and mortality of volunteered diseases and the clinical signs that owners attributed to each disease were obtained; information regarding the impact of these diseases and health concerns was also sought. Results A total of 40 separate disease and health problems were volunteered by carthorse- and donkey-owners. Horse-owners volunteered a musculoskeletal syndrome (with the local name 'bird', clinical signs suggest possible disease pathologies including equine exertional rhabdomyolysis), colic and epizootic lymphangitis most frequently, whereas donkey-owners volunteered sarcoids, nasal discharge and wounds to occur most frequently. One problem (coughing) was volunteered frequently by both horse- and donkey-owners. Owners demonstrated knowledge of differing manifestations and severity of these problems, which resulted in differing impacts on the working ability of the animal. Conclusions Although many of the diseases and clinical signs had been previously reported, this study also identified some previously unreported priorities such as rabies in donkeys, an unidentified musculoskeletal syndrome in horses and respiratory signs in both horses and donkeys. The information gathered during this participatory study with owners may be used to inform future veterinary and educational programme interventions, as well as identify future research priorities. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance poses a significant threat to the continued successful use of antimicrobial agents for the treatment of bacterial infections. While the epidemiology of antimicrobial resistance in bacteria from man has been studied extensively, less work has been undertaken in companion animals, particularly horses. Methicillin-resistant Staphylococcus aureus has been identified as a cause of infections, with a low prevalence of nasal carriage by horses in the community but higher for hospitalised horses. Molecular characterisation has shown methicillin-resistant Staphylococcus aureus strains either to be predominantly of types associated with horses or of sequence type ST398. Antimicrobial-resistant Escherichia coli (including multidrug-resistant and extended spectrum β-lactamase-producing isolates) have caused infections and been documented in faecal carriage by horses, with many significant resistance mechanisms identified. More sporadic reports and molecular characterisation exist for resistance in other bacteria such as enterococci, Salmonella, Acinetobacter and Pseudomonas species. Limited work has been undertaken evaluating risk factors and much of the epidemiology of antimicrobial resistance in bacteria from horses remains to be determined. [ABSTRACT FROM AUTHOR]

Reasons for performing study Recurrent colic occurs frequently in the general horse population but little evidence exists about what factors place horses at greater risk of recurrent colic. Objectives To quantify time-varying and non time-varying risk factors for recurrent colic among horses attended by first-opinion veterinary surgeons in northwest England. Study design Nested case-control study. Methods A nested case-control study was conducted on data from a prospective longitudinal cohort study of 127 horses recruited subsequent to an episode of medical colic. Data were collected on management and recurrent colic episodes at 4-monthly intervals by telephone questionnaires. All recurrent colic episodes were selected as cases; controls were unmatched and randomly selected from all horse-time at risk. Data relating to the 30 days prior to the date of colic or control selection were used to determine exposure status. Multivariable logistic regression analyses were used to determine risk factors for recurrent colic. Results In total, 59 cases and 177 controls were included. The final model showed that horses that displayed crib-biting/windsucking (odds ratio [ OR] 10.1, 95% confidence interval [ CI] 2.5-41.0) or weaving behaviour ( OR 3.9, 95% CI 1.5-10.1) had an increased risk of recurrence of colic. Increasing time at pasture reduced the risk of recurrence ( OR 0.99, 95% CI 0.99-1.0). A significant interaction was found suggesting that the risk associated with crib-biting/windsucking may be modified by feeding fruit/vegetables; however, further research is required before recommendations for feeding practices can be made. Conclusions This study suggests that sufficient access to pasture may be an important means of reducing recurrent colic risk. The behavioural risk factors highlight individuals who may be at increased risk of recurrent colic and whose colic prevention strategies should be carefully managed. [ABSTRACT FROM AUTHOR]

Reasons for performing study The factors associated with outcome following solar foot penetration involving synovial structures treated using endoscopic lavage have not been described in the UK population. Objectives To provide descriptive data on horses with synovial contamination or sepsis following solar penetration in 4 UK equine referral hospitals and to identify specific factors associated with the outcome. Study design Retrospective case series. Methods Data were collected from 4 veterinary hospitals. Follow-up data were obtained via a telephone questionnaire. Two multivariable logistic regression models were generated. Model 1 included all horses with synovial contamination following foot penetration undergoing surgical treatment, with the outcome variable being euthanasia during hospitalisation. Model 2 included all horses surviving anaesthesia, with the outcome variable being failure to return to pre-injury athletic function. Results Ninety-five horses were included. Overall, 56% of horses survived to discharge and 36% of horses returned to pre-injury athletic function. Model 1 included penetration of the central frog sulcus (odds ratio [ OR] 10, 95% confidence interval [ CI] 1.9-51.8), concurrent distal phalanx involvement ( OR 32, 95% CI 2.6-101.9), increasing days to presentation ( OR 1.2, 95% CI 1.0-1.3) and hospital. Model 2 included increasing days to presentation ( OR 1.1, 95% CI 1.1-1.6), breed ( OR 32, 95% CI 2.2-135.4), more than one surgery ( OR 5.6, 95% CI 1.0-32.7) and hospital. Conclusions and potential relevance Synovial involvement following solar foot penetration has a guarded prognosis for survival to discharge and a poor prognosis for return to pre-injury athletic function. Penetration of the central sulcus of the frog and distal phalanx involvement are associated with euthanasia during hospitalisation. Delayed referral and hospitalisation are associated with both euthanasia and failure to return to pre-injury athletic function. Breed and more than one surgery are associated with failure to return to pre-injury athletic function. These data may assist veterinary surgeons and owners to make evidence-based decisions when managing cases with synovial involvement following solar foot penetration. [ABSTRACT FROM AUTHOR]

Reasons for performing study Risk factors for large colon volvulus ( LCV) in the horse have not been previously reported. Knowledge of these risk factors may allow the introduction of measures that could be taken to minimise the incidence of LCV. Objectives To investigate risk factors for LCV in the horse. Methods A prospective, multicentre, unmatched case-control study was conducted over a 24 month period in the UK. Data on 69 cases and 204 control horses, from 4 veterinary hospitals, were obtained via telephone questionnaires. Multivariable logistic regression was used to identify associations between horse and management-level variables and the likelihood of LCV. Results Increasing height, multiple colic episodes in the previous 12 months and mares, with a greater odds ratio in mares that had previously foaled, were associated with increased risk of LCV. Receiving medication (excluding anthelmintic treatment) in the previous 7 days and quidding behaviour were also associated with increased risk. Management-level variables associated with greater risk of LCV were an increase in the hours of stabling in the previous 14 days, an increasing number of horses on the premises, and 3 or more people involved in the horse's care. Variables related to nutrition associated with increased risk of LCV were being fed hay, being fed sugar-beet, a change in pasture in the previous 28 days, and an alteration in the amount of forage fed in the last 7 days. Conclusions This study has identified factors that may assist in the recognition of horses with increased risk of LCV and factors that might be altered to minimise the incidence of LCV. Potential relevance Clinicians can use this information to identify horses at risk of LCV and to provide evidence-based advice to owners of these horses. [ABSTRACT FROM AUTHOR]

Reasons for performing study Palmar/plantar osteochondral disease ( POD) is a common, debilitating condition in Thoroughbred racehorses; however, training- and racing-related factors associated with this disease are unknown. Objectives To determine horse-, racing- and training-related risk factors for POD. The general hypotheses were that early training and racing, and increased intensity of racing and training, lead to increased severity of POD. Methods The metacarpo/metatarsophalangeal joints of 164 Thoroughbred racehorses were examined at post mortem and graded for third metacarpal and metatarsal POD. The relationships between training- and racing-related factors and grade of POD in each condyle were determined using multilevel, multivariable, ordinal logistic regression models. Results A total of 1288 condyles were graded. Factors associated with higher grades of POD were the total lifetime number of races, an increase in gallop sessions in the previous season, racing before import to Hong Kong and an increase in the number of short (8-16 weeks) between-race intervals per season. Horses in their first racing season were more likely to have lower POD grades, while horses that had a long between-race interval (greater than 16 weeks) in the season prior to euthanasia were also more likely to have lower POD grades. Lower POD grades were significantly more likely as days since last race increased up to 400 days. Age at first race was not significantly associated with grade of POD. Conclusions and potential relevance Cumulative racing exposure and training intensity in the previous season were associated with higher grades of POD, supporting the hypothesis that the disease is due to repetitive loading. Longer between-race intervals and increased time since racing were associated with lower POD grades, which may indicate that lesions heal. Further work is required to enable optimisation of racing and training programmes to reduce the frequency and severity of this disease. [ABSTRACT FROM AUTHOR]

Reasons for performing study Palmar/plantar osteochondral disease ( POD) of the metacarpo/metatarsophalangeal ( Mc/ MtPh) joints is common in Thoroughbred racehorses, but there is little information on predilection sites, associated pathologies and clinical signs. Objectives To describe the distribution of POD at post mortem examination and to examine the association of POD with other pathologies and clinical histories. Methods The Mc/ MtPh joints of 102 Thoroughbred racehorses were examined post mortem. Gross pathology of associated osteochondral elements, suspensory ligament and flexor tendons was recorded. Clinical data were extracted from computerised records. Relationships between all Mc/ MtPh joint pathologies, clinical data and grade of POD in each condyle were determined using multilevel, ordinal logistic regression models. Results Palmar/plantar osteochondral disease was recorded ( grade 1-3 in at least one condyle) in 80.4% (95% confidence interval 71-88) of horses. The grade of POD was significantly higher in the forelimb, where the medial condyle had higher grades, than in the hindlimb, where the POD grade was higher in the lateral condyle. There was a significant positive relationship between POD grade and multiple other joint pathologies, whereas grades of linear fissures had a negative relationship with grade of POD. There was no relationship between grade of POD and tendon and suspensory ligament gross pathology, although horses with a history of tendon injury had significantly lower POD grades. Horses that had a clinical history of a Mc/ MtPh joint problem had higher POD grades. In addition, horses that had been retired from racing for more than 2 months at the date of death had significantly lower POD grades. Conclusions and potential relevance Palmar/plantar osteochondral disease has specific predilection sites. Horses with a clinical history of Mc/ MtPh-associated lameness had higher POD grades, whereas those with a history of superficial digital flexor tendon injury and retired horses had lower grades. The progression of POD and its ability to heal requires further evaluation. [ABSTRACT FROM AUTHOR]

Reasons for performing study: Feed supplements are commonly used by owners to alleviate headshaking; however, randomised, controlled trials are required to assess their efficacy. Objective: To determine the efficacy of a feed supplement for alleviation of the clinical signs of headshaking using a randomised, blinded, placebo-controlled trial. Methods: Using a crossover design, 44 horses previously diagnosed with chronic idiopathic headshaking received both the supplement and a matching placebo per os for 28 days with a washout period between of 14 days. Video recordings were taken at rest and exercise prior to the study and at the end of both periods of treatment. The degree of headshaking was assessed in a blinded, randomised manner by 2 veterinary surgeons. At the same time points, owners completed a questionnaire to assess the severity of headshaking signs. A Wilcoxon signed rank test was used to compare the scores while on supplement and placebo. Results: Using the video assessments, there was no significant difference between scores while on supplement compared with placebo (P = 0.7). Using the questionnaire responses, there was no significant difference between scores for any activity when the placebo and the supplement were compared with each other. However, owners reported significant improvement during all activities for both placebo and supplement compared with pretreatment scores. Conclusions and potential relevance: The supplement offered no benefit over a placebo in alleviating the clinical signs of headshaking. There appeared to be a significant proxy placebo effect when the outcome was based on subjective owner perception of clinical signs. This study demonstrated no beneficial effect of this supplement on the clinical signs of headshaking. The study did show a significant placebo effect, thereby highlighting the necessity of properly conducted, randomised controlled trials, with blinding, to assess true treatment effects in trials in animals. [ABSTRACT FROM AUTHOR]

Reasons for performing study: The pattern of long-term survival and specific factors associated with long-term survival have not previously been evaluated in horses with a strangulating large colon volvulus (LCV). Objectives: To provide data on the long-term survival of horses with LCV and to identify pre-, intra- and post operative variables associated with survival. Methods: Clinical data and long-term follow-up information were obtained from 116 horses with a strangulating LCV (≥360°) undergoing general anaesthesia. Two multivariable Cox proportional hazards models for post operative survival time were developed: Model 1 included all horses and evaluated preoperative variables and Model 2 included horses that survived anaesthesia and evaluated pre-, intra- and post operative variables. Results: The study population comprised 116 horses. Eighty-nine (76.7%) survived general anaesthesia. Of these, the percentage that survived until discharge, to one year and to 2 years was 70.7%, 48.3% and 33.7%, respectively. Median survival time for horses that survived general anaesthesia was 365 days. In Model 1 increased preoperative packed cell volume (PCV) was significantly associated with reduced post operative survival (hazard ratio [HR] 1.08, 95% confidence interval [CI] 1.05-1.11). However, this effect changed over time. In Model 2 abnormal serosal colour intraoperatively (HR 3.61, 95% CI 1.55-8.44), increased heart rate at 48 h post surgery (HR 1.04, 95% CI 1.02-1.06), and colic during post operative hospitalisation (HR 2.63, 95% CI 1.00-6.95), were all significantly associated with reduced post operative survival. Conclusions: Survival time in horses with a LCV was associated with preoperative PCV, serosal colour, heart rate at 48 h post operatively and colic during post operative hospitalisation. Potential relevance: This study provides evidence-based information on the long-term survival of horses with LCV and identifies parameters that may assist decision-making by clinicians and owners. [ABSTRACT FROM AUTHOR]

Reasons for performing study: Antimicrobial use is known to select for the emergence of resistant strains of bacteria; therefore prudent use in both human and veterinary medicine is essential to preserve their efficacy. Objectives: To characterise antimicrobial prescribing patterns in UK equine practice and evaluate factors associated with prescribing. Methods: A postal questionnaire including 4 clinical scenarios was sent to 740 veterinary surgeons that treat horses. Data were collected on the clinician, their practice and sources of information regarding antimicrobials and their use. Multivariable logistic regression analysis was used to ascertain factors associated with 5 outcomes; prescribing off-licence drugs; prescribing at incorrect doses; prescribing 3rd or 4th generation cephalosporins; prescribing fluoroquinolones and prescribing potentiated sulphonamides. Results: Questionnaires were completed by 38% of veterinary surgeons who were sent questionnaires. Less than 1% of practices had antimicrobial use guidelines. Trimethoprim-sulphonamides were most commonly prescribed in each clinical scenario. Eleven percent of prescriptions were for antimicrobial drugs not licensed for use in horses in the UK. Five percent of prescriptions for licensed antimicrobials were under the recommended dose rate and 56% over the recommended dose rate. Fluoroquinolones and 3rd and 4th generation cephalosporins accounted for 1 and 3% of prescriptions, respectively. Veterinary surgeons working at referral practices were more likely to prescribe 3rd and 4th generation cephalosporins and fluoroquinolones and off-licence antimicrobials whereas those working in first-opinion practices were more likely to prescribe potentiated sulphonamides. Sources of information regarding antimicrobials also had an effect on prescribing. Conclusions and potential relevance: Prescription of antimicrobials at inappropriate doses was common even when provided with the weight of the animal. It is uncommon for UK equine veterinary practices to have guidelines for antimicrobial use. The introduction of such guidelines could lead to more prudent use of antimicrobials. [ABSTRACT FROM AUTHOR]

Reasons for performing study: Equine pituitary pars intermedia dysfunction (PPID) is an ageing-related neurodegenerative disorder. The prevalence and risk factors for PPID using seasonally adjusted basal adrenocorticotropic hormone (ACTH) concentrations in aged horses have not been previously reported. Objectives: To determine the prevalence, risk factors and clinical signs predictive for PPID in a population of horses aged ≥15 years in Queensland, Australia. Methods: Owner-reported data was obtained using a postal questionnaire distributed to an equestrian group. A subgroup of surveyed owners were visited and a veterinary physical examination performed on all horses aged ≥15 years. Blood samples were analysed for basal plasma alpha melanocyte-stimulating hormone (α-MSH) and ACTH concentrations, routine haematology and selected biochemistry. Aged horses with elevations above seasonally adjusted cut-off values for basal plasma ACTH were considered positive for PPID. Positive horses were compared with their aged counterparts to determine risk factors and clinical signs associated with PPID. Results: Pituitary pars intermedia dysfunction was prevalent in aged horses (21.2%) despite owners infrequently reporting it as a known or diagnosed disease or disorder. Numerous clinical or historical signs were associated with an increased risk of PPID in the univariable model, but only age (odds ratio (OR) 1.18; 95% confidence interval (CI) 1.11-1.25, P<0.001) and owner-reported history of hirsutism (OR 7.80; 95% CI 3.67-16.57, P<0.001) remained in the final multivariable model. There were no routine haematological or biochemical variables supportive of a diagnosis of PPID. Conclusions and potential relevance: Pituitary pars intermedia dysfunction occurs commonly in aged horses despite under-recognition by owners. The increased risk of PPID with age supports that this is an ageing associated condition. Aged horses with clinical or historical signs consistent with PPID, especially owner-reported hirsutism (delayed shedding and/or long hair coat), should be tested and appropriate treatment instituted. [ABSTRACT FROM AUTHOR]

Reasons for performing study: The sensitivity and specificity of basal plasma α-melanocyte-stimulating hormone (α-MSH) and adrenocorticotrophic hormone (ACTH) for the diagnosis of pituitary pars intermedia dysfunction (PPID) has not been evaluated in a population-based study. Objectives: To evaluate basal plasma α-MSH and ACTH concentrations for the diagnosis of PPID in a population of horses aged ≥15 years. Methods: Owner-reported data were obtained using a postal questionnaire distributed to an equestrian group. A subgroup of surveyed owners was visited and veterinary examination performed on horses aged ≥15 years. Blood samples were analysed for plasma α-MSH and ACTH concentrations. Seasonally adjusted cut-off values for α-MSH and ACTH concentrations for the diagnosis of PPID were obtained using Youden index values against a clinical gold standard diagnosis (hirsutism plus 3 or more clinical signs of PPID). Results: α-melanocyte-stimulating hormone and ACTH were highly correlated with each other and with clinical and historical indicators of PPID. The increase in both α-MSH and ACTH with increasing numbers of clinical signs in affected horses supports a spectrum of disease. Both variables were affected by season, with derived cut-off values being higher in autumn compared with other seasons. Sensitivity and specificity were moderate and good in nonautumn seasons (59 and 93%, respectively) for α-MSH using a cut-off of 52.0 pmol/l. Sensitivity and specificity were good in nonautumn seasons (80 and 83%, respectively) for ACTH using a cut-off of 29.7 pg/ml. For both α-MSH and ACTH, sensitivity and specificity were close to 100% for samples obtained during the autumn period. Conclusions and potential relevance: Basal plasma α-MSH and ACTH had moderate-to-good sensitivity and specificity for the diagnosis of PPID, which improved substantially during the autumn period, suggesting this may be the ideal time to test. Further studies to develop seasonally adjusted reference intervals for different geographical locations are warranted. [ABSTRACT FROM AUTHOR]

Summary Reasons for performing study: The increasing prevalence of antimicrobial-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and antimicrobial-resistant Escherichia coli represents a significant problem. However, the carriage of such bacteria by horses in the UK has not been well characterised. Objectives: To estimate the prevalence of nasal carriage of MRSA and faecal carriage of antimicrobial-resistant E. coli amongst horses in the general equine community of the mainland UK. Methods: A cross-sectional study of horses recruited by 65 randomly selected equine veterinary practices was conducted, with nasal swabs and faecal samples collected. Faecal samples were cultured for antimicrobial-resistant E. coli. Nasal swabs were cultured for staphylococcal species; methicillin-resistant isolates identified as S. aureus were characterised by SCC mec and spa gene typing. Multilevel logistic regression models were used to calculate prevalence estimates with adjustment for clustering at practice and premises levels. Spatial variation in risk of antimicrobial resistance was also examined. Results: In total, 650 faecal samples and 678 nasal swabs were collected from 692 horses located on 525 premises. The prevalence of faecal carriage of E. coli with resistance to any antimicrobial was 69.5% (95% CI 65.9-73.1%) and the prevalence of extended-spectrum β-lactamase (ESBL)-producing E. coli was 6.3% (95% CI 4.1-9.6%). The prevalence of nasal carriage of MRSA was 0.6% (95% CI 0.2-1.5%). Spatial analysis indicated variation across the UK for risk of carriage of resistant and multidrug-resistant (resistant to more than 3 antimicrobial classes) E. coli. Conclusions and potential relevance: Carriage of MRSA by horses in the community appears rare, but the prevalence of antimicrobial-resistant E. coli (including ESBL-producing E. coli) is higher. A high prevalence of antimicrobial-resistant bacteria could have significant health implications for the horse population of the UK. [ABSTRACT FROM AUTHOR]

Tumour necrosis factor alpha (TNF-α) is a pro-inflammatory cytokine that plays a crucial role in the regulation of inflammatory and immune responses. In all vertebrate species the genes encoding TNF-α are located within the major histocompatability complex. In the horse TNF-α has been ascribed a role in a variety of important disease processes. Previously two single nucleotide polymorphisms (SNPs) have been reported within the 5′ un-translated region of the equine TNF-α gene. We have examined the equine TNF-α promoter region further for additional SNPs by analysing DNA from 131 horses ( Equus caballus), 19 donkeys ( E. asinus), 2 Grant's zebras ( E. burchellii boehmi) and one onager ( E. hemionus). Two further SNPs were identified at nucleotide positions 24 (T/G) and 452 (T/C) relative to the first nucleotide of the 522 bp polymerase chain reaction product. A sequence variant at position 51 was observed between equidae. SNaPSHOT™ genotyping assays for these and the two previously reported SNPs were performed on 457 horses comprising seven different breeds and 23 donkeys to determine the gene frequencies. SNP frequencies varied considerably between different horse breeds and also between the equine species. In total, nine different TNF-α promoter SNP haplotypes and their frequencies were established amongst the various equidae examined, with some haplotypes being found only in horses and others only in donkeys or zebras. The haplotype frequencies observed varied greatly between different horse breeds. Such haplotypes may relate to levels of TNF-α production and disease susceptibility and further investigation is required to identify associations between particular haplotypes and altered risk of disease. [ABSTRACT FROM AUTHOR]

Few studies have examined the effect of dietary restriction in horses with equine metabolic syndrome (EMS). This study aimed to determine improvements in insulin sensitivity following dietary restriction for 6 weeks, and to determine if the improvement would be greater in horses receiving short-chain fructo-oligosaccharides (sc-FOS). Dietary management involved feeding grass hay, restricted to 1.25% of body mass (BM) as daily dry matter intake and soaked in cold water prior to feeding, with the addition of a vitamin and mineral nutraceutical supplement with or without the addition of sc-FOS (10 g/100 kg). Soaking the hay resulted in a significant reduction in non-structural carbohydrates (38%, P = 0.01 ), digestible energy (6.78%, P = 0.01) and water soluble minerals. Following 6 weeks of dietary restriction with soaked grass hay and nutraceutical supplement, horses lost an average of 6.8% BM and showed reductions in body condition score (BCS) and belly circumference. Sensitivity to insulin improved overall, as determined by the total insulin response during the combined glucose insulin test. The magnitude of improvement in insulin sensitivity was associated with the degree of insulin resistance recorded at out-set, and the extent of overall losses in BM and BCS, but was independent of the addition of sc-FOS. The nutraceutical supplement was highly palatable and no adverse effects were noted. From the findings of this study a strict dietary program in combination with a specifically designed vitamin and mineral nutraceutical supplement can be recommended to obtain rapid improvements in BM, BCS and insulin sensitivity of animals presenting with EMS. [ABSTRACT FROM AUTHOR]