Determinants of Thoroughbred yearling sales price in the UK.

Background: Industry-level figures suggest that up to two-thirds of Thoroughbred breeding operations in the UK are unprofitable and that around half of sales transactions of Thoroughbred yearlings, commercial breeders' predominant income source, return a loss. The industry strategy currently endorses investment in stallion covering fee; however, to date, a comprehensive evaluation of sales price determinants in the UK setting is lacking and could better inform economic decision making to improve profitability. Methods: Sales catalogue and Weatherbys' stud book data from all Thoroughbred yearlings sold at the 2020 Tattersalls October yearling sale in the UK were used to build a hedonic sales price model. Explanatory variables representing sire, dam, yearling and sales attributes were evaluated. The final model's accuracy was assessed using out-of-sample data from all yearlings sold in the equivalent 2021 sale. Results: In 2020, a total of 1506 catalogued yearlings, representing around 30% of the UK Thoroughbred foal crop, were sold, with a median price of £42,575 (interquartile range 15,750‒105,000; range 840‒3,570,000). The sires' covering fee, maternal siblings' race performance attributes, whether the yearling was the dams' first foal, consignment size, catalogue book and day of sale within book significantly influenced auction price; however, relationships were complex with significant interaction and confounding observed. The mean model forecasting error was £2074. The use of data from only one sale could affect generalisability. Conclusions: These novel findings can inform breeding decisions to maximise profitability, give context for current industry strategies and can inform valuations of breeding stock.

Associations between turn out practices and rates of musculoskeletal disease and injury in Thoroughbred foals and yearlings on stud farms in the United Kingdom.

BACKGROUND: Early-life locomotor activity during turn out may alter susceptibility to musculoskeletal disease and injury via modulation of behaviours and tissue development during growth. OBJECTIVES: Investigate associations between turn out practices and rates of musculoskeletal disease and injury in young Thoroughbreds on stud farms in the United Kingdom. STUDY DESIGN: Prospective cohort. METHODS: Daily records were kept on location and duration of turn out for 134 Thoroughbred foals on six stud farms, from birth until leaving the farm or study exit. Data on veterinary-attended episodes of musculoskeletal disease or injury were collated concurrently. Average daily turn out times (hours), areas (acres) and group size (n foals) were calculated for rolling 7- and 30-day periods of age. Multivariable Cox regression, including farm as a random effect, was used to investigate associations between turn out practices and musculoskeletal disease and injury. RESULTS: The overall incidence of musculoskeletal disease or injury was 5.3 cases/100 foal-months at risk (95% confidence interval [CI]: 4.2-6.6). Compared with 24/7 turn out, average daily turn out times of between 9 and 23 hours over a 7-day period were associated with a 4.6-fold increase in musculoskeletal injury rate (95% CI: 1.7-12.3; P < 0.001), adjusting for farm and paddock area. Each 1-acre increase in the average daily turn out area during the 4th month of life, reduced the rate of musculoskeletal disease and injury between 6 and 18 months of age by 24% (hazard ratio 0.76, 95% CI: 0.58-0.99; P < 0.001), adjusting for farm and turn out time. MAIN LIMITATIONS: Non-random sample of participants may affect generalisability. Use of veterinary-attended events likely underestimates disease/injury rates. CONCLUSIONS: Results suggest that disruptions or alterations to turn out time routines increase injury risk and should be avoided where possible. Turn out in larger paddocks, particularly before weaning, may confer protection against subsequent musculoskeletal disease and injury.

A study of the impact of the COVID-19 pandemic on equine veterinary care in the UK.

Background: During the COVID-19 pandemic, equine health care in the UK may have been adversely affected due to mandated changes in the delivery of veterinary healthcare and the potential for reduced health-seeking behaviour. Methods: Electronic patient records (EPRs) were analysed to describe veterinary activity for all equids under the active care of 20 veterinary practices in the UK in the 12 months before and after the introduction of the first UK lockdown. Pre-pandemic and pandemic levels of clinical activity were compared. Further comparisons of care, including immediate management and treatment, were made following a detailed review of EPRs from randomly selected subsets of equids under care in four time periods. Results: All measures of activity and face-to-face interaction were lower in the early pandemic period than in the equivalent pre-pandemic period. Compared to pre-pandemic, the early pandemic was associated with a decrease in prophylactic care and non-urgent diagnostic imaging and an increase in systemic non-steroid anti-inflammatory prescription. Convenience sampling of veterinary practices may have limited the generalisability of the findings. The quality of EPRs was variable. Conclusions: While equine veterinary activity was significantly disrupted in the early pandemic period, there was a rapid return to pre-pandemic levels of activity. Subsequent lockdowns appeared to have had little effect on veterinary care.

Testing and Refining the Ethical Framework for the Use of Horses in Sport.

In 2021, in response to an acknowledged need for universal, consistent ethics to guide decision making in the horse sport sector, Campbell published a theoretical ethical framework for the use of horses in competitive sport. The research reported here tested the applied usefulness of that theoretical ethical framework through stakeholder engagement in a three-round modified Delphi study and refined it to develop a practical decision-making tool which can be applied consistently across multiple equestrian disciplines. Stakeholders from a broad range of equestrian competitive disciplines participated in the research. Participants were required to apply the ethical framework to a pre-determined ethical dilemma, individually (Rounds 1 and 2) and within a group (Round 3), and at the end of each round to complete a questionnaire designed to gauge opinion and user experience. At the completion of each round of testing, the theoretical framework was refined based on stakeholder feedback. Results showed that participants perceived useability and application of the framework to generally increase with each round. Qualitative content analysis identified key concepts, including cognition (e.g., broadens/deepens thinking) and application (e.g., considers multiple angles from a variety of information sources, needs to be a short/simple process). Results suggested that the refined framework is beneficial for group decision making across a wide variety of ethical issues and equestrian competitive disciplines. The framework thus has the potential to improve equine welfare through facilitating consistent ethical decision making in which the interests of the horse are prioritized.

Incidence of disease, injury and death in Thoroughbred foals and yearlings on stud farms in the UK and Ireland.

BACKGROUND: Up-to-date estimates of early-life morbidity and mortality in Thoroughbreds are lacking. METHODS: A birth cohort was established on Thoroughbred stud farms across the UK and Ireland. All veterinary interventions for disease or injury between birth and 18 months of age or leaving the study were recorded. Multilevel Poisson regression models with farm and foal as random effects were fitted to estimate incidence rates. RESULTS: Data were available for 3328 foal-months at risk for 275 foals on seven farms. The overall rates of disease and injury requiring veterinary intervention and mortality were 11.9 cases/100 foal-months at risk (95% confidence interval [CI] 8.6-16.2) and 0.2 cases/100 foal-months at risk (95% CI 0.1-0.4), respectively. Almost half (n = 133/273, 49%, 95% CI 43-55) of the live-born cohort required veterinary intervention for musculoskeletal disease or injury, equating to 5.8 cases/100 foal-months at risk (95% CI 4.1-8.2), predominantly reported as developmental orthopaedic disease (DOD). LIMITATIONS: Convenience sampling of participants may affect the generalisability of the findings. CONCLUSIONS: Rates of musculoskeletal disease and injury, in particular DOD, on Thoroughbred stud farms were high. Further work to identify modifiable risk factors and further understanding of the economic impact of these conditions and long-term consequences for musculoskeletal health and performance is required.

Use of antimicrobials licensed for systemic administration in UK equine practice.

BACKGROUND: Judicious antimicrobial use (AMU) is important for preserving therapeutic effectiveness. Large-scale studies of antimicrobial prescribing can provide clinical benchmarks and help identify opportunities for improved stewardship. OBJECTIVES: To describe systemic AMU in UK equine practice and identify factors associated with systemic and Category B (third and fourth generation cephalosporins, quinolones and polymixins) AMU. STUDY DESIGN: Retrospective cohort. METHODS: Anonymised electronic patient records (EPRs) for all equids attended by 39 UK veterinary practices between 1 January and 31 December 2018 were collected via the VetCompass programme. Systemic antimicrobial prescriptions were identified using electronic keyword searches. Indications for AMU were determined through manual review of a randomly selected subset of EPRs. The types and frequency of systemic antimicrobials prescribed and indications were summarised using descriptive statistics. Mixed-effects logistic regression was used to evaluate practice- and horse-related risk factors. RESULTS: Systemic antimicrobials were prescribed to 12 538 (19.5%, 95% confidence interval [CI]: 19.2%-19.8%) of 64 322 equids attended in 2018. Category B antimicrobials were prescribed to 1.9% (95% CI: 1.8%-2.0%) of attended equids and in 8.9% (95% CI: 8.5%-9.4%) of antimicrobial courses. Bacteriological culture was performed in 19.1% (95% CI: 17.1%-21.3%) of Category B antimicrobial courses. The most commonly prescribed antimicrobial classes were potentiated sulphonamides (50.2% of equids receiving antimicrobials) and tetracyclines (33.5% of equids receiving antimicrobials). Integumentary disorders were the most common reason for systemic AMU (40.5% of courses). Urogenital disorders were the most common reason for Category B AMU (31.1% of courses). Increased odds of systemic and Category B AMU were observed in equids <1 year compared with those aged 5-14 years. Breed was associated with AMU, with odds of systemic and Category B AMU highest in Thoroughbreds and Thoroughbred crosses. MAIN LIMITATIONS: Convenience sample of practices may limit generalisability. CONCLUSIONS: Empirical use of Category B antimicrobials remains commonplace.

Bayesian accuracy estimates and fit for purpose thresholds of cytology and culture of endometrial swab samples for detecting endometritis in mares.

The overall aim of this work was to identify the potential impact of misclassification errors associated with routine screening and diagnostic testing for endometritis in mares. Using Bayesian latent class models (BLCM), specific objectives were to: 1) estimate the diagnostic accuracy of cytology and culture of endometrial swab samples to detect endometritis in mares; 2) assess the impact of different cytology thresholds on test accuracy and misclassification costs; and 3) assess the sensitivity (Se) and specificity (Sp) of a diagnostic strategy including both tests interpreted in series and parallel. Diagnostic and pre-breeding endometrial swab samples collected from 3448 mares based at breeding premises located in the South East of England between 2014 and 2020 were retrospectively analysed. Culture results were classified as positive according to three different case definitions: (A) > 90% of the growth colonies were a monoculture; (B) pathogenic or pathogenic and non-pathogenic bacteria were identified; and (C) any growth was observed. Endometrial smears were graded based on the percent of polymorphonuclear cells (PMN) per high power field (HPF). A hierarchical BLCM was fitted using the cross-tabulated results of the three culture case definitions with a cytology threshold fixed at > 0.5% PMN. Fit for purpose cytology thresholds were proposed using a misclassification cost analysis in the context of good antimicrobial stewardship and for varying endometritis prevalence estimates. Median [95% Bayesian credible intervals (BCI)] cytology Se estimates were 6.5% (2.2-11.6), 6.4% (2.2-10.8) and 6.3% (2.2-10.8) for scenario A, B and C, respectively. Median (95% BCI) cytology Sp estimates were 88.8% (83.1-94.8), 88.9% (83.9-93.8) and 88.8% (84.0-93.8) for scenarios A, B and C, respectively. Median (95% BCI) culture Se estimates were 37.5% (29.9-46.0), 42.3% (33.8-51.1) and 46.4% (35.7-55.9) for scenarios A, B and C, respectively. Median (95% BCI) culture Sp estimates were 92.8% (84.3-99.0), 91.5% (82.5-98.0) and 90.8% (80.1-97.4) for scenarios A, B and C, respectively. Regardless of the culture case definition, Se and Sp of cytology (> 0.5% PMN) was lower than previously reported for swab samples in studies using histology as the reference standard test. The misclassification cost term decreased as the cytology threshold increased for all scenarios and all prevalence contexts, suggesting that, regardless of the endometritis prevalence in the population, increasing the cytology threshold would reduce the misclassification costs associated with false positive mares contributing to good antimicrobial stewardship.

Mixed-Effects Modelling of the Risk Factors Associated with Multiple Pregnancies in Thoroughbred Mares.

Multiple pregnancies (MPs) are commonly diagnosed during breeding management of mares. Whilst some studies have reported on factors associated with the risk of MPs, few have utilised multivariable data analysis to control for confounding variables. A prospective cohort study of Thoroughbred broodmares was conducted with information collected on 27 factors. Mixed-effects logistic regression was used to determine risk factors for MPs. Mare, stallion, stud, and veterinarian were evaluated as random effects. The prevalence of MPs in 1754 mares and 2245 pregnancies was 16.06% (95% confidence interval [CI] = 14.54, 17.58). Multiple ovulations (OR = 15.57, 95% CI = 11.88, 20.53) and treatment with cloprostenol (OR = 1.35, 95% CI = 1.015, 1.80) were associated with increased odds of MPs following multivariable analysis. Mares that foaled at the start of the breeding season (OR = 0.66, 95% CI = 0.47, 0.94), conceived at the second or more oestrus cycles (OR = 0.60, 95% CI= 0.43, 0.84), or identified with a uterine cyst (OR = 0.63, 95% CI = 0.40, 0.97) were at reduced odds of conceiving MPs. Mare, stallion, stud, and veterinarian were not associated with MPs. These findings provide possible explanations as to why the prevalence of MPs but not MOs have increased over the last decade.

The effect of stress fracture occurring within the first 12 months of training on subsequent race performance in Thoroughbreds in Hong Kong.

BACKGROUND: Racehorses are at an increased risk of stress fracture within the first 12 months of racing and when resuming training after a break. Research in these high-risk periods and on the effect of performance post-recovery is limited. OBJECTIVES: To describe the occurrence of stress fractures, diagnosed by nuclear scintigraphy (NS), in racehorses' first 12 months training in Hong Kong, and their impact on racing performance and career length. STUDY DESIGN: Retrospective 1:2 matched case-control study. METHODS: Clinical records of horses with NS-diagnosed stress fractures within 365 days of import between 2006 and 2018 were collated. Cases and controls were matched on import date. Univariable conditional logistic regression compared signallment, pre-fracture training and post-recovery racing performance between cases and matched controls. Shared Frailty Cox regression analysed time from import to fracture and total career length. RESULTS: Eighty-seven horses sustained a NS-diagnosed fracture within their first year in Hong Kong (incidence risk 1.7% [95% confidence interval (CI) 1.4%-2.1%; N = 5180]). The humerus (42.0%; 95% CI 31.8%-52.6%; n = 39) and tibia (28.0%; 95% CI 19.1%-38.2%; n = 26) were the most common stress fracture sites. Cases missed a median of 63 days (Interquartile range (IQR) 49-82) of training because of fracture. Within the 12 months following diagnosis, case horses had a median of four (IQR 2-4, P < .0001) fewer race starts and were down HK$ 206 188 (IQR HK$ 0-436 800, P = .007) in race earnings compared to controls. Career length did not significantly differ between cases and controls (median 2 years and 3 months; IQR 15.3-39.1 months; P = .2). MAIN LIMITATIONS: Only stress fractures diagnosed by NS were included, hence, the study is not representative of all stress fractures occurring in racehorses in Hong Kong. CONCLUSIONS: Racehorses sustaining a stress fracture within 1 year of entering Hong Kong lost significant time in training, earnings and race starts. However, overall career length was unaffected.

Incidence and causes of pregnancy loss after Day 70 of gestation in Thoroughbreds.

BACKGROUND: Pregnancy loss after Day 70 of gestation manifests as abortion, stillbirth or perinatal death. While previous studies have reported the diagnoses of laboratory submissions, none have quantified the incidence and causes of abortions, stillbirths and perinatal mortality at a population level. OBJECTIVES: To report the incidence and causes of pregnancy loss after Day 70 of gestation in a cohort of Thoroughbreds. STUDY DESIGN: Retrospective cohort study. METHODS: Outcomes of Day 70 pregnancies were collected from eight Thoroughbred farms over the 2013-2017 breeding seasons. Stud, veterinary and laboratory records were supplemented with publicly available data. Cause of loss was categorised using custom criteria. RESULTS: Data were collected on 3,586 pregnancies from 1,802 mares. The incidence risk of a pregnancy failing to produce a live foal at 24 hours post parturition was 7.3% (95% confidence interval (CI) 6.5-8.2, equating to 7.3 cases per 100 Day-70 pregnancies). The incidence of pregnancy loss between Day 70 and 300 of gestation, Day 301-315 and stillbirth/perinatal death was 4.0% (95% CI 3.4-4.7), 0.3% (95% CI 0.2-0.6) and 1.4% (95% CI 1.1-1.9) respectively. Of the pregnancy losses where tissue was available, 61.1% were submitted for post-mortem examination. The incidence risk of loss due to umbilical cord-related pathologies was 1.5% (95% CI 1.1-1.9), 0.4% (95% CI 0.2-0.6) for noninfectious placental disease and 0.3% (95% CI 0.2-0.6) for both infectious placentitis and Equine Herpesvirus infection. No primary diagnosis was made in 11.2% of the cases which underwent full post-mortem examination. MAIN LIMITATIONS: It was not possible to differentiate between intra-partum stillbirth and early post-partum death. CONCLUSION: Pregnancy loss after Day 70 of gestation is a significant source of loss in the Thoroughbred with umbilical cord-related pathologies being the most commonly diagnosed cause. Reporting the incidence of pregnancy loss at a population level with clear case definitions will allow for accurate global comparisons.

Serological surveillance reveals patterns of exposure to H5 and H7 influenza A viruses in European poultry.

Influenza A viruses of H5 and H7 subtype in poultry can circulate subclinically and subsequently mutate from low to high pathogenicity with potentially devastating economic and welfare consequences. European Union Member States undertake surveillance of commercial and backyard poultry for early detection and control of subclinical H5 and H7 influenza A infection. This surveillance has moved towards a risk-based sampling approach in recent years; however, quantitative measures of relative risk associated with risk factors utilized in this approach are necessary for optimization. This study describes serosurveillance for H5 and H7 influenza A in domestic and commercial poultry undertaken in the European Union from 2004 to 2010, where a random sampling and thus representative approach to serosurveillance was undertaken. Using these representative data, this study measured relative risk of seropositivity across poultry categories and spatially across the EU. Data were analysed using multivariable logistic regression. Domestic waterfowl, game birds, fattening turkeys, ratites, backyard poultry and the 'other' poultry category holdings had relatively increased probability of H5 and/or H7 influenza A seropositivity, compared to laying-hen holdings. Amongst laying-hen holdings, free-range rearing was associated with increased probability of H7 seropositivity. Spatial analyses detected 'hotspots' for H5 influenza A seropositivity in western France and England, and H7 influenza A seropositivity in Italy and Belgium, which may be explained by the demographics and distribution of poultry categories. Findings suggest certain poultry category holdings are at increased risk of subclinical H5 and/or H7 influenza A circulation, and free-range rearing increases the likelihood of exposure to H7 influenza A. These findings may be used in further refining risk-based surveillance strategies and prioritizing management strategies in influenza A outbreaks.

Risk factors for race-day fatality in flat racing Thoroughbreds in Great Britain (2000 to 2013).

A key focus of the racing industry is to reduce the number of race-day events where horses die suddenly or are euthanased due to catastrophic injury. The objective of this study was therefore to determine risk factors for race-day fatalities in Thoroughbred racehorses, using a cohort of all horses participating in flat racing in Great Britain between 2000 and 2013. Horse-, race- and course-level data were collected and combined with all race-day fatalities, recorded by racecourse veterinarians in a central database. Associations between exposure variables and fatality were assessed using logistic regression analyses for (1) all starts in the dataset and (2) starts made on turf surfaces only. There were 806,764 starts in total, of which 548,571 were on turf surfaces. A total of 610 fatalities were recorded; 377 (61.8%) on turf. In both regression models, increased firmness of the going, increasing racing distance, increasing average horse performance, first year of racing and wearing eye cover for the first time all increased the odds of fatality. Generally, the odds of fatality also increased with increasing horse age whereas increasing number of previous starts reduced fatality odds. In the 'all starts' model, horses racing in an auction race were at 1.46 (95% confidence interval (CI) 1.06-2.01) times the odds of fatality compared with horses not racing in this race type. In the turf starts model, horses racing in Group 1 races were at 3.19 (95% CI 1.71-5.93) times the odds of fatality compared with horses not racing in this race type. Identification of novel risk factors including wearing eye cover and race type will help to inform strategies to further reduce the rate of fatality in flat racing horses, enhancing horse and jockey welfare and safety.

Relationship between serum biomarkers of cartilage and bone metabolism and joint injury in young Thoroughbred racehorses in training.

OBJECTIVE: To compare serum concentrations of biomarkers of cartilage and bone metabolism between racehorses with a carpal or metacarpophalangeal or metatarsophalangeal (ie, fetlock) joint injury and matched uninjured control horses, determine changes in biomarker concentrations following joint injury, and establish the biomarkers' diagnostic test performance. ANIMALS: 50 Thoroughbred racehorses with a carpal or fetlock joint injury and 50 matched uninjured horses (control horses). PROCEDURES: Serum concentrations of 2 cartilage synthesis biomarkers (carboxy-terminal propeptide of type II collagen [CPII] and chondroitin sulfate epitope 846 [CS846]), 2 cartilage degradation biomarkers (neoepitope generated by collagenase cleavage of type II collagen [C2C] and cross-linked carboxy-terminal telopeptide fragments of type II collagen [CTX-II]), and serum activity of a bone formation marker (bone-specific alkaline phosphatase [BAP]) were measured around the time of injury diagnosis and monthly thereafter for as long as possible. RESULTS: Injured horses as a group and horses specifically with fetlock joint injuries had significantly lower serum CPII concentrations and significantly higher serum BAP activities than matched control horses. Concentrations of CTX-II were decreased between 2 and 4 months following joint injury. Measurement of CPII concentration at baseline could distinguish between injured horses and control horses with a sensitivity of 82% and specificity of 50%. CONCLUSIONS AND CLINICAL RELEVANCE: Although significant differences in specific biomarker concentrations between horses with carpal and fetlock joint injuries and matched control horses were identified, there was no convincing evidence of the suitability of these biomarkers as diagnostic or prognostic tools in a clinical setting.

Food-specific serum IgE and IgG reactivity in dogs with and without skin disease: lack of correlation between laboratories.

BACKGROUND: Despite conflicting data on their utility and no reports on interlaboratory reproducibility, serum food-specific antibodies are commonly assayed in first-opinion canine practice. HYPOTHESIS/OBJECTIVES: To determine both the variability of test results between two laboratories and the frequencies and magnitudes of food reactivity in dogs of different disease status. ANIMALS: Sera were obtained from eight dogs with cutaneous adverse food reaction (Group A), 22 with nonfood-induced atopic dermatitis (Group B), 30 with an allergic/inflammatory phenotype (Group C), 12 with miscellaneous skin diseases (Group D) and nine healthy dogs (Group E). METHODS: Paired sera were submitted to two laboratories (A and B) for assays of food-specific IgE and IgG antibodies. RESULTS: Numbers of positive IgE and IgG tests determined by each laboratory in Groups A, B, D and E were comparable (Group C not included). Significant differences in the magnitude of IgE reactivity between groups for each allergen were seen only for lamb (Laboratory A, P = 0.003); lamb reactivity in Group D exceeded Group E (P = 0.004) but was comparable between all other groups. Agreement (kappa statistic) between the two laboratories' tests was 'moderate' for one antigen (potato IgE), 'fair' for four (corn IgE, rice IgE and IgG and soya bean IgG), 'slight' for eight (six IgE and two IgG) and 'less than chance' for the remaining six antigens (three IgE and three IgG). CONCLUSIONS AND CLINICAL IMPORTANCE: These laboratories' tests appear to have dubious predictive clinical utility because they neither correlate nor distinguish between dogs of different disease status.

Helping working Equidae and their owners in developing countries: monitoring and evaluation of evidence-based interventions.

There are an estimated 112 million Equidae (horses, donkeys, mules) in the developing world, providing essential resources for their owners' livelihoods and well-being. The impoverished situation of their owners and the often harsh conditions in which they work mean that the animals' welfare is a cause for concern. A number of equine non-governmental organisations (NGOs) operate within working equid communities providing veterinary care, education and training programmes aimed at improving equine welfare. However, there is little published information available that describes monitoring and evaluation (M&E) of such interventions using objective outcome-based indicators and where baseline data are available. The aim of this paper is to summarise the peer-reviewed reports of M&E in this sector and identify the key issues which need to be addressed in ensuring that such evaluations provide useful information on the work of these organisations. A rigorous evidence base for designing future interventions will provide an opportunity for enhancing the effectiveness of working equid NGO operations. Increased availability of M&E reports in the peer-reviewed literature will enable NGOs to learn from one another and disseminate to a wider audience information on the role of working Equidae and the issues they face.

Risk factors for equine laminitis: a case-control study conducted in veterinary-registered horses and ponies in Great Britain between 2009 and 2011.

Laminitis is a highly debilitating disease of the foot known to have a complex and multifactorial aetiology of metabolic, inflammatory, traumatic or vascular origin. The disease has major welfare implications due to unrelenting pain associated with degenerative changes, which often necessitate euthanasia on welfare grounds. Despite this, there have been few high-quality studies investigating risk factors for equine laminitis, and only a limited number of risk factors have been previously investigated. The aim of this study was to conduct a case-control study of risk factors for active episodes of veterinary-diagnosed laminitis in horses and ponies attended by veterinary practitioners in Great Britain, based on multivariable statistical analyses. Questionnaires were received for 1010 animals, comprising 191 laminitis cases and 819 controls. Factors associated with an increased risk of laminitis were weight gain in the previous 3 months, summer and winter months compared to spring, new access to grass in the previous 4 weeks, box rest in the previous week, owner-reported history of laminitis, lameness or foot-soreness after shoeing/trimming, existing endocrinopathic (pituitary pars intermedia dysfunction and equine metabolic syndrome) disease and increasing time since the last anthelmintic treatment. Factors associated with a decreased risk of laminitis were increasing height (cm), feeding of additional supplements in the previous week and transportation in the previous week. Novel associated factors were identified that may aid in the management and prevention of the disease in the veterinary-registered equine population.

Exercise affects joint injury risk in young Thoroughbreds in training.

The aim of this study was to identify exercise-related risk factors for carpal and metacarpo- and metatarso-phalangeal (MCP/MTP) joint injury occurrence in young Thoroughbreds in flat race training. In a 2-year prospective cohort study, daily exercise and joint injury data were collected from horses in 13 training yards in England. Four injury categories were defined: (1) localised to a carpal or MCP/MTP joint based on clinical examination and/or use of diagnostic analgesia with no diagnostic imaging performed; (2) localised to a carpal or MCP/MTP joint with no abnormalities detected on diagnostic images; (3) abnormality of subchondral bone and/or articular margin(s) identified using diagnostic imaging; (4) fracture or fragmentation identified by diagnostic imaging. Multivariable Cox regression analysis was conducted to determine risk factors for injury occurrence, by type (carpal or MCP/MTP) and category. Exercise distances at canter and high speed in different time periods were modelled as continuous time-varying variables. A total of 647 horses spent 7785months at risk of joint injury and 184 injuries were recorded. Increasing daily canter distance reduced the risk of Category 1 and Category 3 injuries whereas greater 30-day canter distances increased Category 4 injury risk. More weekly high-speed exercise increased Category 1 injury risk. MCP/MTP injury risk reduced with increasing daily canter distance but increased with accumulation of canter or high-speed exercise since entering training, whereas accumulation of canter exercise was marginally associated with reduced carpal injury risk. Risk of all injury types varied significantly between trainers. The results of this study suggest that regular canter exercise is generally beneficial for joint health, while accumulation of high-speed exercise detrimentally affects MCP/MTP joints.

Risk factors for equine laminitis: a systematic review with quality appraisal of published evidence.

Epidemiological studies into the risk factors for naturally-occurring equine laminitis are limited. There are a small number of such studies, although the results are inconsistent and remain disputed. The reasons for the conflicting results remain unclear. The aim of this review was to critically evaluate previous research in order to identify publications which provide the best evidence of risk factors for naturally-occurring equine laminitis. A systematic review of English language publications was conducted using MEDLINE (1950-2010), CAB Direct (1910-2010) and IVIS (1997-2010). Additional publications were included by searching bibliographies. Search terms included laminitis, equine, risk factors and epidemiology. Publications which compared a case population to a control population and made inferences about parameters as risk factors for naturally-occurring equine laminitis were included. Information was extracted using predefined data fields, including 18 study quality indicators. In total, 17 publications were fully appraised. Six were considered to provide the most reliable information about risk factors for naturally-occurring laminitis. Information on signalment was well researched and there was good evidence for an association with chronic laminitis and increasing age. There remain inconsistent results for many other horse-level risk factors including gender, breed and bodyweight. Previous publications estimating risk factors for equine laminitis were of reasonable quality, although they were limited in the number and scope of the risk factors studied. High-quality, evidence-based studies are needed to identify further risk factors and to establish consensus over previously identified risk factors for different equine populations.

Frequency of equine laminitis: a systematic review with quality appraisal of published evidence.

Equine laminitis is a highly debilitating disease of the foot. Despite its perceived importance, epidemiological characteristics are poorly understood and the true frequency of the disease remains unclear. The objective of this study was to retrospectively assess previous research to identify publications which provide the best evidence of the frequency of naturally-occurring equine laminitis. A systematic review of English language publications was conducted using MEDLINE (1950-2010), CAB Direct (1910-2010) and IVIS (1997-2010). Additional publications were included by searching bibliographies. Search terms included laminitis, equine, frequency, prevalence and incidence. Studies that allowed frequency estimations to be made for naturally-occurring equine laminitis were included. Information was extracted using predefined data fields, including 13 study quality indicators. Sixty-nine publications were appraised. Ten were considered to provide the most reliable information, estimating the frequency of equine laminitis ranging from 1.5% to 34%. Previous publications estimating laminitis frequency were generally poor quality. Laminitis frequency varied across publications however the publications included in this review focussed on many of the different underlying laminitis aetiologies and comparison of the frequencies between groups would be inappropriate. High-quality evidence-based studies are needed to estimate the true disease frequency in different equine populations.

Epidemiology of exertional rhabdomyolysis susceptibility in standardbred horses reveals associated risk factors and underlying enhanced performance.

BACKGROUND: Exertional rhabdomyolysis syndrome is recognised in many athletic horse breeds and in recent years specific forms of the syndrome have been identified. However, although Standardbred horses are used worldwide for racing, there is a paucity of information about the epidemiological and performance-related aspects of the syndrome in this breed. The objectives of this study therefore were to determine the incidence, risk factors and performance effects of exertional rhabdomyolysis syndrome in Standardbred trotters and to compare the epidemiology and genetics of the syndrome with that in other breeds. METHODOLOGY/PRINCIPAL FINDINGS: A questionnaire-based case-control study (with analysis of online race records) was conducted following identification of horses that were determined susceptible to exertional rhabdomyolysis (based on serum biochemistry) from a total of 683 horses in 22 yards. Thirty six exertional rhabdomyolysis-susceptible horses were subsequently genotyped for the skeletal muscle glycogen synthase (GYS1) mutation responsible for type 1 polysaccharide storage myopathy. A total of 44 susceptible horses was reported, resulting in an annual incidence of 6.4 (95% CI 4.6-8.2%) per 100 horses. Female horses were at significantly greater risk than males (odds ratio 7.1; 95% CI 2.1-23.4; p = 0.001) and nervous horses were at a greater risk than horses with calm or average temperaments (odds ratio 7.9; 95% CI 2.3-27.0; p = 0.001). Rhabdomyolysis-susceptible cases performed better from standstill starts (p = 0.04) than controls and had a higher percentage of wins (p = 0.006). All exertional rhabdomyolysis-susceptible horses tested were negative for the R309H GYS1 mutation. CONCLUSIONS/SIGNIFICANCE: Exertional rhabdomyolysis syndrome in Standardbred horses has a similar incidence and risk factors to the syndrome in Thoroughbred horses. If the disorder has a genetic basis in Standardbreds, improved performance in susceptible animals may be responsible for maintenance of the disorder in the population.