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Background: There is little knowledge of the prescription of nonsteroidal anti-inflammatory drugs (NSAIDs) and whether their prescription varies between countries., Objective: To describe prescription practices of NSAIDs in equids in the United Kingdom (UK), United States of America (USA) and Canada., Study Design: Descriptive observational study., Methods: Free-text electronic medical records from 141,543 equids from 10 equine practices in the UK, 255,777 equids from 7 equine practices with 20 branches from the USA and 2 practices with 7 branches from Canada were evaluated. A validated text-mining technique was used to describe the proportion of equids prescribed NSAIDs at least once in these countries. The choice of NSAIDs in orthopaedic and colic cases was evaluated., Results: The prescription of NSAIDs is more common in the USA (42.4%) and Canada (34.2%) than in the UK (28.6%). Phenylbutazone and flunixin meglumine were the drugs mostly prescribed in all countries. While flunixin meglumine was most prescribed with colic cases in all countries, a proportion received phenylbutazone despite this drug being licensed for use only with musculoskeletal disease. Phenylbutazone was the most commonly prescribed drug in cases with orthopaedic disease followed by flunixin meglumine in all countries. Only a small proportion of cases received meloxicam, ketoprofen or firocoxib., Main Limitations: The retrospective design might have resulted in an unknown number of incomplete records, particularly in the reporting of colic and orthopaedic disease. Although the data set is large, the relatively small number of practices recruited from each country may introduce bias., Conclusions: Clinical practice can differ between countries although the influence of individual practitioners and practice-specific policy on apparent intercountry differences requires further research. Despite several other NSAIDs being available and a substantial effort being made to evaluate their efficacy, the prescription of NSAIDs other than phenylbutazone and flunixin meglumine remains rather limited., (© 2018 EVJ Ltd.)

Background: There is a dearth of literature on pseudopregnancy in the bitch, with only a few treatment-based studies published since the 1990s. Pseudopregnancy may be under-recognised in bitches and may account for a proportion of behavioural cases seen in veterinary practices including aggression. Little is known about commonly used treatments for overtly pseudopregnant bitches and it is possible that current regimes may not be prescribed for a sufficient duration to control any clinical signs including, physical and behavioural changes. To investigate current trends in diagnosis and treatment of canine pseudopregnancy, a postal survey was sent to 2000 randomly selected veterinary surgeons in UK veterinary practices. The questionnaire queried how often vets recognise cases of pseudopregnancy in spayed and entire bitches, which physical or behavioural signs are commonly recognised for diagnosis, and which management or treatment protocols are used., Results: The response rate was 19.8% (397/2000). Ninety-six percent of veterinary surgeons reported seeing pseudopregnant bitches showing behavioural changes without any physical changes within the last 12 months. Of those behavioural changes, collecting and mothering objects was the most frequently reported behavioural sign (96%). Ninety-seven percent of vets had seen aggression in pseudopregnant bitches. Nevertheless, only 52% of vets routinely asked owners about behavioural changes during consultations. Forty-nine percent of respondents reported seeing pseudopregnancy in spayed bitches. The most commonly reported physical sign was enlarged mammary glands and/or milk production (89%). Treatment options varied (surgical, medical or none) and depended on duration and severity of physical and behavioural signs, owners' preference, cost, concurrent disease, drug availability and previous history., Conclusions: This is the largest epidemiological study of canine pseudopregnancy in the UK. The prevalence and severity of clinical signs in dogs with pseudopregnancy are variable and possibly under-estimated. Dogs with overt pseudopregnancy experience diverse physical and behavioural changes and information on standard treatment protocols are lacking. Although, progress on our understanding of diagnosis and treatment of pseudopregnancy in spayed and entire bitches has been made, further studies are warranted.

The aim of this paper is to identify risk factors associated with equine fractures in flat horse racing of Thoroughbreds in North America. Equine fractures were defined as any fracture sustained by a horse during a race. This was a cohort study that made use of all starts from the racecourses reporting injuries. The analysis was based on 2,201,152 racing starts that represent 91% of all official racing starts in the USA and Canada from 1st January 2009-31st December 2014. Approximately 3,990,000 workout starts made by the 171,523 Thoroughbreds that raced during that period were also included in the analysis. During this period the incidence of equine fractures was 2 per 1000 starts. The final multivariable logistic regression models identified risk factors significantly associated (p<0.05) with equine fracture. For example, horses were found to have a 32% higher chance of sustaining a fracture when racing on a dirt surface compared to a synthetic surface; a 35% higher chance if they had sustained a previous injury during racing and a 47% higher chance was also found for stallions compared to mares and geldings. Furthermore, logistic regression models based on data available only from the period 2009-2013 were used to predict the probability of a Thoroughbred sustaining a fracture for 2014. The 5% of starts that had the highest score in our predictive models for 2014 were found to have 2.4 times (95% CI: 1.9-2.9) higher fracture prevalence than the mean fracture prevalence of 2014. The results of this study can be used to identify horses at higher risk on entering a race and could help inform the design and implementation of preventive measures aimed at minimising the number of Thoroughbreds sustaining fractures during racing in North America., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Reasons for Performing Study: Fractures of the lateral condyle of the third metacarpus (MC3) are a significant welfare concern in horseracing worldwide., Objectives: The primary aim of this work was to identify magnetic resonance (MR) image-detectable prefracture markers that have the potential for use as a screening tool to identify horses at significant risk of catastrophic fracture., Study Design: Case-control study of bone-level risk factors for fracture in racehorses., Methods: A total of 191 MC3s from horses, with and without lateral condylar fracture of MC3, were subjected to MR imaging. The depth of dense subchondral/trabecular bone was measured at several sites around the distal end of the bone and regression analyses were conducted to identify differences in this depth between horses with and without lateral condylar fracture., Results: Greater depth of dense subchondral/trabecular bone in the palmar half of the lateral parasagittal groove of distal MC3 was associated with an increased likelihood of being from a horse that had sustained a fracture. Receiver operator characteristic analysis was used to identify the optimal cut-off in the depth of dense subchondral/trabecular bone at this site to best discriminate fracture status. Positive and negative predictive values were calculated using the prevalence of fracture within the current study and also a prevalence estimate for the wider racehorse population., Conclusions: There is a requirement to identify suitable prescreening test(s) to eliminate many true negative horses and increase the prevalence of prefracture pathology in the sub population that would be screened using MR imaging, in turn maximising the positive predictive value of this test., (© 2016 EVJ Ltd.)

Reasons for Performing Study: Changes in subchondral bone density, induced by the repetitive cyclical loading of exercise, may potentiate fatigue damage and the risk of fracture., Objectives: To use computed tomography (CT) to characterise bone density patterns at the articular surface of the third metacarpal bone in racehorses with and without lateral condylar fractures., Study Design: Case control METHODS: Computed tomographic images of the distal articulating surface of the third metacarpal bone were obtained from Thoroughbred racehorses subjected to euthanasia in the UK. Third metacarpal bones were divided into 3 groups based on lateral condyle status; fractured (FX, n = 42), nonfractured contralateral condyle (NFX, n = 42) and control condyles from horses subjected to euthanasia for reasons unrelated to the third metacarpal bone (control, n = 94). Colour CT images were generated whereby each colour represented a range of pixel values and thus a relative range of bone density. A density value was calculated qualitatively by estimating the percentage of each colour within a specific region. Subchondral bone density was assessed in 6 regions from dorsal to palmar and 1 mm medial and lateral to the centre of the lateral parasagittal groove in NFX and control condyles and 1 mm medial and lateral to the fracture in FX condyles., Results: Bone density was significantly higher in the FX and NFX condyles compared with control condyles for all 6 regions. A significantly higher bone density was observed in FX condyles relative to NFX condyles in the lateral middle and lateral palmar regions. Fractured condyles had increased heterogeneity in density among the 6 regions of interest compared with control and NFX condyles., Conclusions: Adjacent to the fracture, a focal increase in bone density and increased heterogeneity of density were characteristic of limbs with lateral condylar fractures compared with control and NFX condyles. These differences may represent pathological changes in bone density that increase the risk for lateral condylar fractures in racehorses., (© 2015 EVJ Ltd.)

OBJECTIVE To identify risk factors associated with fatal injuries in Thoroughbred racehorses in the United States and Canada. DESIGN Retrospective study. ANIMALS 1,891,483 race starts by 154,527 Thoroughbred racehorses at 89 racetracks in the United States and Canada from 2009 to 2013. PROCEDURES Data were extracted from the Equine Injury Database, which contained information for 93.9% of all official flat racing events in the United States and Canada during the 5-year observation period. Forty-four possible risk factors were evaluated by univariate then multivariable logistic regression to identify those that were significantly associated with fatal injury (death or euthanasia of a horse within 3 days after sustaining an injury during a race). RESULTS 3,572 race starts ended with a fatal injury, resulting in a period incidence rate of 1.9 fatal injuries/1,000 race starts. Twenty-two risk factors were significantly associated with fatal injury. Risk of fatal injury was greater for stallions than for mares and geldings and increased as the number of previous nonfatal injuries and race withdrawals and level of competitiveness (eg, horse's winning percentage and race purse) of the horse or race increased. CONCLUSIONS AND CLINICAL RELEVANCE Results identified several risk factors associated with fatal injuries in Thoroughbred racehorses. This information can be used as a guideline for the identification of racehorses at high risk of sustaining a fatal injury and in the design and implementation of preventative measures to minimize the number of fatal injuries sustained by horses competing in flat racing in the United States and Canada.

Objectives: 1) To describe a novel echocardiographic view (left cranial oblique) for the assessment of the pulmonary artery in dogs 2) To compare this novel view with other standard views., Animals: Prospective inclusion of 48 echocardiograms performed on client-owned dogs., Methods: Two standard views and the novel view were compared for quality of 2D images and spectral Doppler traces and also for pulmonary annulus diameter and spectral Doppler velocities. Association between view, heart rate and body weight and quality, annulus diameter, pulsed-wave and continuous-wave velocities were analyzed using regression analysis. Agreement between views was assessed by Bland-Altman analysis. Pulsed-wave and continuous-wave velocities were compared using the sign test for medians., Results: Forty-eight studies were undertaken of which thirty-nine were analyzed. The quality of 2D images was associated with view and heart rate. No significant difference was found in quality of spectral Doppler traces between views. Annulus diameter showed significant association with view, heart rate and weight. This measured about 0.26 cm less on one particular view. Spectral Doppler velocities showed no association with view, heart rate or weight. Continuous-wave velocities were significantly higher than pulsed-wave velocities in every view., Conclusions: The novel left cranial oblique view can be used as an additional tool for the echocardiographic evaluation of the pulmonary artery. The pulmonary annulus diameter was consistently smaller measured from the one standard view compared to both the novel and other standard views. Comparable quality and velocities were obtained for spectral Doppler. Continuous-wave and pulsed-wave modes were not interchangeable., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The aim of this study was to evaluate risk factors associated with developing epistaxis in jump racing in Great Britain (GB). A retrospective analysis of records from horses running in all hurdle and steeplechase races in GB between 2001 and 2009 identified diagnoses of epistaxis whilst still at the racecourse. Data were used from 603 starts resulting in epistaxis (event) and 169,065 starts resulting in no epistaxis (non-event) in hurdle racing, and from 550 event starts and 102,344 non-event starts in steeplechase racing. Two multivariable logistic regression models to evaluate risk factors associated with epistaxis were produced. The potential effect of clustering of data (within horse, horse dam, horse sire, trainer, jockey, course, race and race meet) on the associations between risk factors and epistaxis was examined using mixed-effects models. Multiple factors associated with increased risk of epistaxis were identified. Those identified in both types of jump racing included running on firmer ground; horses with >75% of career starts in flat racing and a previous episode of epistaxis recorded during racing. Risk factors identified only in hurdle racing included racing in the spring and increased age at first race; and those identified only in steeplechase racing included running in a claiming race and more starts in the previous 3-6 months. The risk factors identified provide important information about the risk of developing epistaxis. Multiple avenues for further investigation are highlighted, including unmeasured variables at the level of the racecourse. The results of this study can be used to guide the development of interventions to minimise the risk of epistaxis in jump racing., (Copyright © 2015. Published by Elsevier Ltd.)

Objective: To evaluate ex vivo cyclooxygenase (COX) inhibition and compare in vitro and ex vivo COX-1 inhibition by flunixin meglumine and firocoxib in horses., Animals: 4 healthy horses for in vitro experiments and 12 healthy horses (6 males and 6 females; 5 Thoroughbreds, 5 Warmbloods, and 2 ponies) undergoing elective surgery for ex vivo experiments., Procedures: 12 horses received flunixin meglumine (1.1 mg/kg, IV, q 12 h) or firocoxib (0.09 mg/kg, IV, q 24 h). Blood samples were collected before (baseline) and 2 and 24 hours after NSAID administration. Prostanoids (thromboxane B2, prostaglandin E2, and prostaglandin E metabolites) served as indicators of COX activity, and serum drug concentrations were measured by use of high-performance liquid chromatography. An in vitro coagulation-induced thromboxane B2 assay was used to calculate drug concentration-COX-1 inhibition curves. Effect of time and treatment on COX activity was determined. Agreement between in vitro and ex vivo measurement of COX activity was assessed with Bland-Altman analysis., Results: At 2 and 24 hours after NSAID administration, COX-1 activity was reduced, compared with baseline activity, for the flunixin meglumine group only and relative COX-1 activity was significantly greater for the firocoxib group, compared with that for the flunixin meglumine group. There was no significant change in COX-2 activity after surgery for either group. Bland-Altman analysis revealed poor agreement between in vitro and ex vivo measurement of COX-1 activity., Conclusions and Clinical Relevance: Compared with flunixin meglumine, firocoxib had COX-1-sparing effects ex vivo in equine patients that underwent elective surgery.

Background: Sagittal ratio values (SRVs) of cervical vertebrae are used for ante-mortem diagnosis of cervical vertebral stenotic myelopathy, but intraobserver and interobserver variability in measurement may influence radiographic interpretation of vertebral stenosis in horses with neurological disease., Objectives: To determine intraobserver repeatability in SRVs, intra- and interobserver agreement in SRVs and whether or not agreement was influenced by animal age., Animals: Forty-two horses (>1 year old) with neurological disease from which laterolateral computed radiographic images of C2-C7 were obtained., Methods: Four observers made measurements from C2 to C7 for each horse and interobserver agreement for intra- and intervertebral SRVs was determined using Bland-Altman analysis (acceptable agreement: limits of agreement [LOA] ≤ 0.05) on all horses and those ≤3 (n = 25) and >3 (n = 17) years old. Each observer also made repeated measurements for 10 horses and intraobserver repeatability and agreement were determined., Results: Adequate intraobserver repeatability was achieved for 6 sites. Within observers, paired measurements had a median difference ≤5.7%, but a large range in differences often occurred, most frequently at intervertebral sites. For C5, C6, C7, and C3-4, LOA ≤ 0.05 were achieved by at least 1 observer. With the exception of C5 for 1 pair, LOA were >0.05 for interobserver agreement, regardless of animal age. LOA were largest at intervertebral sites., Conclusions and Clinical Importance: Within and between observers, measurement error may limit the diagnostic accuracy of SRVs and result in discrepancies of diagnosis and treatment and warrants consideration when used clinically in horses with neurological disease., (Copyright © 2014 by the American College of Veterinary Internal Medicine.)

Accurate diagnosis of racing injuries can be difficult. The objectives of this study were to describe the postmortem (PM) defined distribution of fatal distal limb fractures (DLF) affecting Thoroughbreds racing in Great Britain between February 1999 and August 2005 and then assess the accuracy of veterinary racecourse diagnoses and examine whether these improved following introduction of a computerised recording system. PM examinations were performed on limbs distal to radius or tibia from all cases of fatal DLF occurring on British racecourses during the study period. Results of these examinations were described and compared with the diagnoses made at the racecourses. Over the study period, fatal DLF prevalence in all race types was 0.63 per 1000 starts (344/545,335), with the lowest frequency (0.34 per 1000 starts) in flat racing on turf and the highest frequency (1.56 per 1000 starts) in national hunt flat races. The prevalence of fatal DLF in steeplechase racing had reduced from that reported previously: from 2.3 to 1 per 1000 starts. Racecourse veterinary identification of fracture presence was good (>93 per cent); however, identification of all fractured bones was poor (<55 per cent). Introduction of a computerised recording system did not significantly improve diagnostic accuracy. The prevalence of fatal DLF has not significantly altered since the 1970s. Techniques such as on course digital radiography to help improve racecourse fracture diagnoses could be introduced.

A retrospective cohort study of distal limb fracture and superficial digital flexor tendon (SDFT) injury in Thoroughbred racehorses was conducted using health records generated by the British Horseracing Authority (BHA) between 2000 and 2010. After excluding records of horses that had both flat and jump racing starts, repeated records were reduced to a single binary record per horse (n = 66,507, 2982 sires), and the heritability of each condition was estimated using residual maximum likelihood (REML) with animal logistic regression models. Similarly, the heritability of each condition was estimated for the flat racing and jump racing populations separately. Bivariate mixed models were used to generate estimates of genetic correlations between SDFT injury and distal limb fracture. The heritability of distal limb fracture ranged from 0.21 to 0.37. The heritability of SDFT injury ranged from 0.31 to 0.34. SDFT injury and distal limb fracture were positively genetically correlated. These findings suggest that reductions in the risk of the conditions studied could be attempted using targeted breeding strategies., (Copyright © 2014. Published by Elsevier Ltd.)

A retrospective cohort study was performed to compare the rates of musculoskeletal injury (MSI) in horses receiving local corticosteroid injection (LCI) with those that were untreated and those prior to treatment. Of the 1911 study horses, 392 had been treated. A LCI was defined as any injection of corticosteroid into or adjacent to a synovial structure, muscle, or tendon/ligament. A MSI was defined as any limb injury identified by a veterinarian, following which the horse did not race for at least 6 months, or was retired. Hazard ratios (HR) comparing hazard of injury following injection to that in non-injected horses and prior to injection were calculated using Cox proportional hazards models. At least one LCI was administered to 392 horses (20.5%; median 2, range 1-16). Most LCIs were performed bilaterally (70.9%) and intra-articularly into the carpal (49.7%) or fore fetlock (29.3%) joints. There were 219 MSIs of which carpal injuries (47%), fore fetlock (22%) and forelimb tendon injuries (16%) were the most common. The incidence rate of MSI in untreated horses and those prior to injection was 1.22 (95% CI 1.04-1.44) injuries/100 horse-months, and following LCI the hazard of MSI was greater (HR 4.83, 3.54-6.61, P<0.001). The hazard ratio returned to levels indistinguishable from before treatment after 49 days. The hazard of MSI in horses following second and subsequent LCIs in the data collection period was greater than in horses following their first LCI (HR 2.10, 1.31-3.36, P=0.002). There was a positive association between LCI and subsequent musculoskeletal injury rates which was most likely due to progression of the musculoskeletal condition which prompted treatment. Assuming horses that received LCI were at increased risk of MSI subsequently, any beneficial effects of the LCI were insufficient to counter this increased risk for at least 49 days after the injection., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Thoroughbred racehorses are subject to non-traumatic distal limb bone fractures that occur during racing and exercise. Susceptibility to fracture may be due to underlying disturbances in bone metabolism which have a genetic cause. Fracture risk has been shown to be heritable in several species but this study is the first genetic analysis of fracture risk in the horse., Results: Fracture cases (n = 269) were horses that sustained catastrophic distal limb fractures while racing on UK racecourses, necessitating euthanasia. Control horses (n = 253) were over 4 years of age, were racing during the same time period as the cases, and had no history of fracture at the time the study was carried out. The horses sampled were bred for both flat and National Hunt (NH) jump racing. 43,417 SNPs were employed to perform a genome-wide association analysis and to estimate the proportion of genetic variance attributable to the SNPs on each chromosome using restricted maximum likelihood (REML). Significant genetic variation associated with fracture risk was found on chromosomes 9, 18, 22 and 31. Three SNPs on chromosome 18 (62.05 Mb - 62.15 Mb) and one SNP on chromosome 1 (14.17 Mb) reached genome-wide significance (p < 0.05) in a genome-wide association study (GWAS). Two of the SNPs on ECA 18 were located in a haplotype block containing the gene zinc finger protein 804A (ZNF804A). One haplotype within this block has a protective effect (controls at 1.95 times less risk of fracture than cases, p = 1 × 10(-4)), while a second haplotype increases fracture risk (cases at 3.39 times higher risk of fracture than controls, p = 0.042)., Conclusions: Fracture risk in the Thoroughbred horse is a complex condition with an underlying genetic basis. Multiple genomic regions contribute to susceptibility to fracture risk. This suggests there is the potential to develop SNP-based estimators for genetic risk of fracture in the Thoroughbred racehorse, using methods pioneered in livestock genetics such as genomic selection. This information would be useful to racehorse breeders and owners, enabling them to reduce the risk of injury in their horses.

Reason for Performing Study: Cheek teeth diastemata are a common cause of painful periodontal disease in horses, but there is limited objective information on their treatment., Objective: To assess the long-term response to diastema widening in clinically affected horses., Study Design: Retrospective study., Method: Medical records from cases of cheek teeth diastemata treated by diastema widening referred to the University of Edinburgh Equine Hospital from 2008 to 2011 were analysed., Results: During this period, 302 horses were diagnosed with clinically significant cheek teeth diastemata, of which 202, median age 11 years, with severe associated periodontitis were treated by widening of 674 problematic diastemata; 89.8% between mandibular cheek teeth and 10.2% between maxillary cheek teeth, with a mean of 1.5 treatments performed per case. These 202 cases showed quidding in 76.2%; weight loss in 33.2%; bitting problems in 20.1% and halitosis in 10.9%, with 5.4% being asymptomatic. Follow-up of 92% of treated cases, a mean of 20.8 months after their initial treatment, showed that 72.6% had complete remission of clinical signs that was permanent (for the duration of this study) in 50.5% and temporary in 22%. A partial response was obtained in 17.2%, no response was obtained in 4.3%, and owners were unsure of response in 5.9%. Clinical improvement was sometimes delayed, with 19% taking >4 weeks following treatment for improvement. Inappropriate sites were burred in individual teeth of 6 horses, causing iatrogenic pulpar exposure in 2 cases, but following treatment none developed clinical signs of apical infection., Conclusions: Diastema widening is an effective but potentially invasive treatment for horses with cheek teeth diastemata with severe periodontitis., Potential Relevance: Diastema widening by trained personnel is suitable for advanced cases of cheek teeth diastema, but many cases require repeated treatments., (© 2013 EVJ Ltd.)

A retrospective cohort study of important musculoskeletal conditions of Thoroughbred racehorses was conducted using health records generated over a 15 year period (n=5062, 1296 sires). The prevalence of each condition in the study population was: fracture, 13%; osteoarthritis, 10%; suspensory ligament injury, 10%; and tendon injury, 19%. Linear and logistic sire and animal regression models were built to describe the binary occurrence of these musculoskeletal conditions, and to evaluate the significance of possible environmental risk factors. The heritability of each condition was estimated using residual maximum likelihood (REML). Bivariate mixed models were used to generate estimates of genetic correlations between each pair of conditions. Heritability estimates of fracture, osteoarthritis, suspensory ligament and tendon injury were small to moderate (range: 0.01-0.20). Fracture was found to be positively genetically correlated with both osteoarthritis and suspensory ligament injury. These results suggest that there is a significant genetic component involved in the risk of the studied conditions. Due to positive genetic correlations, a reduction in prevalence of one of the correlated conditions may effect a reduction in risk of the other condition., (Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Contingency planning for potential equine infectious disease outbreaks relies on accurate information on horse location and movements to estimate the risk of dissemination of disease(s). An online questionnaire was used to obtain unique information linking owner and horse location to characteristics of horse movements within and outwith Great Britain (GB)., Results: This online survey yielded a strong response, providing more than four times the target number of respondents (1000 target respondents) living in all parts of GB. Key demographic findings of this study indicated that horses which were kept on livery yards and riding schools were likely to be found in urban environments, some distance away from the owner's home and vaccinated against influenza and herpes virus. Survey respondents were likely to travel greater than 10 miles to attend activities such as eventing or endurance but were also likely to travel and return home within a single day (58.6%, 2063/3522). This may affect the geographical extent and speed of disease spread, if large numbers of people from disparate parts of the country are attending the same event and the disease agent is highly infectious or virulent. The greatest risk for disease introduction and spread may be represented by a small proportion of people who import or travel internationally with their horses. These respondents were likely to have foreign horse passports, which were not necessarily recorded in the National Equine Database (NED), making the location of these horses untraceable., Conclusions: These results illustrate the difficulties which exist with national GB horse traceability despite the existence of the NED and the horse passport system. This study also demonstrates that an online approach could be adopted to obtain important demographic data on GB horse owners on a more routine and frequent basis to inform decisions or policy pertaining to equine disease control. This represents a reasonable alternative to collection of GB horse location and movement data given that the NED no longer exists and there is no immediate plan to replace it.

Reasons for Performing Study: To investigate upper respiratory tract function in horses, previously undergoing laryngoplasty (LP), using exercising video-endoscopy., Objectives: To evaluate arytenoid abduction and stability, diagnose any concurrent upper airway problems, and correlate these with the owners' perception of success., Methods: Horses undergoing LP during a 6-year period at one hospital were initially included. Those available for re-examination were exercised for a duration and intensity considered maximal for their discipline using an over-ground endoscope. Resting and exercising laryngeal and pharyngeal videos were analysed blindly. Multivariable analysis was used to test associations between resting and exercising endoscopic variables, and also between endoscopic variables and owner questionnaire findings., Results: Forty-one horses were included and 78% had a form of upper airway collapse at exercise, with 41% having complex forms, despite 93% of owners reporting the surgery to have been beneficial. Horses with poor abduction (grades 4 or 5/5) were 6 times more likely to make respiratory noise compared with those with good (grades 2 or 3/5) abduction (P = 0.020; 95% confidence interval [CI] 1.3-27.0), and those not having a ventriculectomy were 4.9 times more likely to produce respiratory noise post operatively (P = 0.048; 95% CI 1.0-23.9). Palatal dysfunction was observed in 24% of horses at rest, and 56% at exercise, with the diagnosis at rest and exercise significantly associated (P = 0.001). Increasing severity of pharyngeal lymphoid hyperplasia (prevalence 61%) was significantly associated with increasing arytenoid abduction (P = 0.01). Thirty-four per cent of horses had aryepiglottic fold collapse and 22% of horses had vocal fold collapse., Conclusions: Many horses that had previously had LP were diagnosed with upper airway abnormalities, despite the procedure being considered as beneficial by most owners., Potential Relevance: When investigating cases of ongoing respiratory noise or poor performance following LP, exercising endoscopy must be considered. Continued respiratory noise may be associated with poor arytenoid abduction and not performing concurrent ventriculectomy., (© 2012 EVJ Ltd.)

Reasons for Performing Study: Although equine motorised dental instruments are widely used, there is limited information on their thermal effect on teeth. The recently described variation in subocclusal secondary dentine depth overlying individual pulp horns may affect heat transmission to the underlying pulps., Objectives: This study compared the effect of 3 different equine motorised dental instruments on the pulpar temperature of equine cheek teeth with and without the use of water cooling. It also evaluated the effect of subocclusal secondary dentine thickness on pulpar temperature changes., Methods: A thermocouple probe was inserted into the pulp horns of 188 transversely sectioned maxillary cheek teeth with its tip lying subocclusally. Pulpar temperature changes were recorded during and following the continuous use of 3 different equine motorised dental instruments (A, B and C) for sequential time periods, with and without the use of water cooling., Results: Using motorised dental instrument B compared with either A or C increased the likelihood that the critical temperature was reached in pulps by 8.6 times. Compared with rasping for 30 s, rasping for 45, 60 and 90 s increased the likelihood that the critical temperature would be reached in pulps by 7.3, 8.9 and 24.7 times, respectively. Thicker subocclusal secondary dentine (odds ratio [OR] = 0.75/mm) and water cooling (OR = 0.14) were both protective against the likelihood of the pulp reaching the critical temperature., Conclusions: Prolonged rasping with motorised dental instruments increased the likelihood that a pulp would be heated above the critical temperature. Increased dentinal thickness and water cooling had protective roles in reducing pulpar heating., Potential Relevance: Motorised dental instruments have the potential to seriously damage equine pulp if used inappropriately. Higher speed motorised dental instruments should be used for less time and teeth should be water cooled during or immediately after instrument use to reduce the risk of thermal pulpar damage., (© 2012 EVJ Ltd.)

Objectives: To (1) assess long-term maintenance of arytenoid cartilage abduction (ACA) after laryngoplasty (LP); and (2) correlate the residual grade of ACA and postoperative abductory loss with arytenoid cartilage stability (ACS) during exercise., Study Design: Case series., Animals: Horses re-examined after laryngoplasty (n = 33)., Methods: Of 89 LP horses (2005-2010), 33 had historic ACA data available and upper airway endoscopy at rest and during over-ground exercise (mean, 33 months; range, 4-71 months) after surgery. ACA grade at 1 and 6 weeks postoperatively were correlated to long-term ACA grade. Effects of long-term ACA grade and magnitude of postoperative abductory loss on ACS during exercise were investigated., Results: Median ACA grade at 1 week (n = 33) was 2, reducing to grade 3 by week 6 (n = 16). Grade 3 abduction was maintained in the long-term. Correlation between ACA at 1 week and the long-term was poor (ρ = .43, P = .1), but there was good correlation between week 6 and long-term (ρ = .89, P < .001). Arytenoid cartilage instability was observed during exercise in 7/33 of horses, and not significantly associated with the ACA grade (P = .50), or the number of grades of ACA lost (P = .64)., Conclusions: Limited abductory loss occurs after 6 weeks postoperatively. Resting ACA grade was not a useful predictor of ACS during exercise., (© Copyright 2013 by The American College of Veterinary Surgeons.)

The objective of this study was to identify risk factors for superficial digital flexor (SDF) tendinopathy in Thoroughbred horses in steeplechase races in the United Kingdom. Potential risk factors for SDF tendinopathy were studied between 1st January 2001 and 31st December 2009 using a cohort study design with 648 injuries sustained in 102,894 starts. Potential risk factors were screened using univariable logistic regression prior to multivariable model building. In the final multivariable model, 12 statistically significant risk factors were identified. Variables that increased the odds of SDF tendinopathy included firmer going, increased horse age, and racing in the summer compared to other seasons. Variables that decreased the odds included having a higher official rating and the number of starts in the preceding days. Fewer and different risk factors were identified than in an equivalent model of SDF tendinopathy in hurdle racing, highlighting potential differences between these disciplines. Further collection of training and racecourse information would be beneficial and may help to explain further some of the associations identified in this study. The results will facilitate the development of strategies to improve overall safety of horses in UK steeplechase racing., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Reasons for Performing the Study: Lateral condylar (LC) fractures of the third metacarpus (McIII) are a common reason for euthanasia in racehorses, and may be the result of repetitive overloading or cumulative pathological change. Magnetic resonance imaging (MRI) allows monitoring of bone and cartilage to detect pathological and adaptive changes that may be precursors of fracture., Objectives: To describe bone and cartilage MRI features in the distal condyles of McIII of Thoroughbred racehorses, with and without condylar fracture., Hypotheses: 1) A greater degree of bone and cartilage adaptation or pathology will be seen in fractured McIIIs compared with their respective contralateral McIIIs. 2) Contralateral McIIIs will have a greater degree of bone and cartilage adaptation or pathology than McIIIs from control horses that did not sustain a LC fracture., Methods: The McIIIs from 96 horses subjected to euthanasia at racecourses were divided into 3 groups: Group 1: nonfractured bones from horses without LC fracture; Group 2: nonfractured bones from horses with unilateral LC fracture; and Group 3: fractured bones from horses with unilateral LC fracture. The MR images were examined and graded for bone and cartilage changes., Results: Nine percent of Group 1 (n = 9) and 11% of Group 2 bones (n = 5) had incomplete LC fractures. Focal palmar necrosis was most frequently detected in bones from Group 1 (12%) compared with Groups 2 (9%) and 3 (4%). The prevalence of bone and/or cartilage abnormalities tended to increase from Group 1 to Group 2 to Group 3., Conclusions: Magnetic resonance imaging is able to detect cartilage and bone changes that may be associated with LC fracture. There was no significant difference in bone/cartilage changes between bones from Groups 1 and 2, despite increased pathology in Group 2 bones., Potential Relevance: Periodic monitoring of bone and/or cartilage changes in distal McIII of Thoroughbred racehorses may help to prevent catastrophic LC fractures., (© 2012 EVJ Ltd.)

Reasons for Performing Study: Superficial digital flexor (SDF) tendinopathy is a common injury in Thoroughbred horses racing over hurdles. Identification of risk factors may allow the introduction of measures to minimise the incidence of this injury., Objective: To identify risk factors for SDF tendinopathy in Thoroughbred horses in hurdle races in the UK., Methods: Potential risk factors for SDF tendinopathy were studied between 1 January 2001 and 31 December 2009 using a retrospective cohort study design with 1031 case starts and 168,637 control starts. Potential risk factors were screened using univariable logistic regression prior to multivariable model building., Results: IN the final multivariable model, 20 statistically significant risk factors were identified. Variables found to be associated with increased odds of SDF tendinopathy included: firmer going; increased horse age at first race; having had a previous SDFT injury; and racing in the summer compared to other seasons. Variables found to be associated with decreased odds included: being trained by a more successful trainer; and having raced more frequently in the preceding 9-12 months., Conclusions: This study identified multiple risk factors associated with SDF tendinopathy, some of which are difficult to explain with the current data source. Factors resulting in increased cumulative horse and tendon fatigue (increased years in racing; carrying increased weight; and racing over longer distances), firm ground, and the presence of previous tendon injury should be considered when attempting to reduce the likelihood of sustaining SDF tendinopathy., Potential Relevance: The results will facilitate the development of strategies to improve the overall safety of horses in hurdle racing in the UK., (© 2012 EVJ Ltd.)

Reasons for Performing Study: Sudden death adversely affects racehorse welfare, jockey safety and the public perception of horseracing., Objective: To describe the risk of racing-associated sudden death in Thoroughbred racehorses in the UK from 2000 to 2007, to identify whether there were risk factors uniquely associated with sudden death and to improve the understanding of the pathogenesis of racing-associated sudden death by identification of risk factors for such cases., Methods: A sudden death was defined as an acute collapse and death, in an apparently healthy Thoroughbred racehorse, during or immediately after racing, in the absence of clinical data indicative of a catastrophic orthopaedic injury. The retrospective study included 201 case race starts and 705,712 control race starts. Univariable and multivariable logistic regression were used to identify risk factors for sudden death at any one start., Results: In the multivariable model, age, distance, race type, season and number of starts in the 60 days prior to the race were associated with sudden death., Conclusions: The risk factors identified in this study are not uniquely associated with sudden death and have been also been identified in studies using all causes of fatality as the outcome. These data suggest that a generic approach to reduce fatal musculoskeletal injury and sudden death may be possible., Potential Relevance: The identification of risk factors allows speculation on the underlying mechanisms of sudden death in racing. This may stimulate hypothesis-led investigations into the pathogenesis of exercise-related arrhythmias, exercise-induced pulmonary haemorrhage and blood vessel rupture., (© 2011 EVJ Ltd.)

Reasons for Performing Study: There is a lack of objective information on the value of ancillary diagnostic techniques used to investigate equine sinus disease, and also on which sinus compartments are commonly affected in this disorder., Objectives: To record the ancillary diagnostic findings used to investigate equine sinus disease and to document which compartments are affected., Materials and Methods: The clinical case records of 200 consecutive cases of sinus disease, including subacute (<2 months' duration) primary (n = 52); chronic (>2 months' duration) primary (n = 37); dental (n = 40); traumatic (n = 13); sinus cyst (n = 26); sinus neoplasia (n = 10); dental related oromaxillary fistula (n = 8); mycotic sinusitis (n = 7) and intra-sinus progressive ethmoid haematoma (n = 7) were retrospectively examined., Results: Nasal endoscopy showed exudate draining from the sino-nasal ostia in 88% of cases and a sino-nasal fistula was present in 15% of cases. Sinoscopy was performed in 79% of cases and was of great diagnostic value. More recently, 22% of cases had fenestration of the ventral conchal bulla performed to allow sinoscopy of the rostral sinus compartments. Radiography was performed in 97% of cases and showed intra-sinus fluid lines to be common (69% prevalence) in subacute primary sinusitis. Radiographic dental apical changes were not specific to dental sinusitis, e.g. 29% of chronic primary sinusitis cases had radiographic dental changes. Scintigraphy was performed in 20% of cases and was helpful in identifying dental apical changes when radiography was inconclusive. Overall, the caudal maxillary (78% involvement) and rostral maxillary (61%) sinuses were most commonly affected, with the ventral conchal sinus (VCS) (54% involvement) and conchofrontal sinuses (48%) less so. The VCS showed the greatest tendency to contain inspissated pus (present in 46% of all affected VCS)., Conclusions: Nasal endoscopy, sinoscopy and skull radiography are of great value in diagnosing the presence and causes of equine sinus disease., (© 2011 EVJ Ltd.)

Reasons for Performing Study: There is limited objective information available on the treatment and the long-term response to treatment of the different types of equine sinus disease., Objectives: To document the treatments and long-term response to these treatments in 200 cases of equine sinus disease (1997-2009)., Methods: The treatments of horses affected with subacute primary sinusitis (n = 52); chronic primary sinusitis (n = 37); dental sinusitis (n = 40); sinus cyst (n = 26); traumatic (n = 13); dental-related oromaxillary fistula (n = 8); sinus neoplasia (n = 10); mycotic sinus disease (n = 7); and intrasinus progressive ethmoid haematoma (n = 7) and the long-term response to these treatments were retrospectively reviewed., Results: Treatments evolved throughout the study and latterly were as conservative as possible, including sinoscopic lavage and standing sinusotomy, with a maxillary sinusotomy approach preferred for the mainly mature horses treated in this study. Removal of intrasinus inspissated pus, including transendoscopically (by sinusotomy and via existing sinonasal fistulae), was the main treatment for chronic primary sinusitis and sinonasal fistulation was seldom performed latterly. Attempted oral extraction of infected cheek teeth, even if unsuccessful, facilitated subsequent dental repulsion, resulting in few post operative problems. Sinus cyst removal carried an excellent prognosis. Except for cases of sinus neoplasia (only 22% cured), an excellent long-term response to treatment (91% fully cured, 7% partially cured) was obtained for all other types of sinus disease following a median of one treatment., Conclusions: More conservative treatments, including removal of intrasinus inspissated pus by sinoscopy, pre-existing sinonasal fistula or sinusotomy, are effective for chronic primary sinus disease. Standing sinusotomy, mainly using a small maxillary site, was suitable for most cases of sinus disease in mature horses., (© 2011 EVJ Ltd.)

Background: Robust demographic information is important to understanding the risk of introduction and spread of exotic diseases as well as the development of effective disease control strategies, but is often based on datasets collected for other purposes. Thus, it is important to validate, or at least cross-reference these datasets to other sources to assess whether they are being used appropriately. The aim of this study was to use horse location data collected from different contributing industry sectors ("Stakeholder horse data") to calibrate the spatial distribution of horses as indicated by owner locations registered in the National Equine Database (the NED)., Results: A conservative estimate for the accurately geo-located NED horse population within GB is approximately 840,000 horses. This is likely to be an underestimate because of the exclusion of horses due to age or location criteria. In both datasets, horse density was higher in England and Wales than in Scotland. The high density of horses located in urban areas as indicated in the NED is consistent with previous reports indicating that owner location cannot always be viewed as a direct substitute for horse location. Otherwise, at a regional resolution, there are few differences between the datasets. There are inevitable biases in the stakeholder data, and leisure horses that are unaffiliated to major stakeholders are not included in these data. Despite this, the similarity in distributions of these datasets is re-assuring, suggesting that there are few regional biases in the NED., Conclusions: Our analyses suggest that stakeholder data could be used to monitor possible changes in horse demographics. Given such changes in horse demographics and the advantages of stakeholder data (which include annual updates and accurate horse location), it may be appropriate to use these data for future disease modelling in conjunction with, if not in place of the NED.

Osteochondrosis is a developmental orthopaedic disease that occurs in horses, other livestock species, companion animal species, and humans. The principal aim of this study was to identify quantitative trait loci (QTL) associated with osteochondritis dissecans (OCD) in the Thoroughbred using a genome-wide association study. A secondary objective was to test the effect of previously identified QTL in the current population. Over 300 horses, classified as cases or controls according to clinical findings, were genotyped for the Illumina Equine SNP50 BeadChip. An animal model was first implemented in order to adjust each horse's phenotypic status for average relatedness among horses and other potentially confounding factors which were present in the data. The genome-wide association test was then conducted on the residuals from the animal model. A single SNP on chromosome 3 was found to be associated with OCD at a genome-wide level of significance, as determined by permutation. According to the current sequence annotation, the SNP is located in an intergenic region of the genome. The effects of 24 SNPs, representing QTL previously identified in a sample of Hanoverian Warmblood horses, were tested directly in the animal model. When fitted alongside the significant SNP on ECA3, two of these SNPs were found to be associated with OCD. Confirmation of the putative QTL identified on ECA3 requires validation in an independent sample. The results of this study suggest that a significant challenge faced by equine researchers is the generation of sufficiently large data sets to effectively study complex diseases such as osteochondrosis.

Reasons for Performing Study: Although low birthweight is a risk factor for neonatal illness, the impact of high birthweight on the health of foals and mares, and on the foals' long-term athletic capability, is unknown., Objectives: To investigate whether: 1) foals that are excessively heavy are associated with an increased prevalence of maternal illness in the first month post partum and reproductive dysfunction in the following season; 2) excessively light or heavy foals are at an increased risk of illness in the first month of life; and 3) birthweight is associated with racing success., Methods: Veterinary records from 230 Thoroughbred mares and 409 foalings were reviewed. Data relating to foaling, foal and mare health during the first month postpartum and subsequent breeding efficiency were extracted. Foals' racing records were obtained and the association between birthweight and these outcomes examined., Results: Mares with heavy foals had a higher prevalence of minor nonreproductive problems than those with light and average foals. Compared to average foals, placental weight was lower in the light group and higher in the heavy group. Light foals took longer to stand, nurse and pass meconium, whereas gestation period and duration of Stage 2 parturition were longer in heavy foals. Heavy foals were at increased risk of nonseptic musculoskeletal conditions and conformational defects. Birthweight was not associated with racing outcomes., Conclusions: High birthweight was associated with increased prevalence of neonatal musculoskeletal conditions but birthweight did not have a major impact on mares' health and reproductive efficiency, orfoals' racing success., Potential Relevance: These data add to the understanding of the impact of birthweight on short- and long-term health outcomes in mares and foals.

The pH measurement of exhaled breath condensate (EBC) may provide a non-invasive method of assessing the lower airways of horses but the methodology used may influence findings. The aim of this study was to investigate the effect of two sampling devices and three methods of condensation surface cooling (ethanol slush, -100°C; dry ice, -75°C; water ice, 0°C) on EBC pH. Each method was tested 30 times using six healthy ponies. Sample pH was determined before and after de-aeration with argon for 10 min. Sampler design was found to significantly affect pH. Samples collected as a liquid had a significantly higher pH than samples frozen during collection (P<0.05). De-aeration resulted in significantly higher pH (P<0.05) with less variation. This study has shown that device design and condensation surface temperature will influence EBC pH, which will prevent a direct comparison of results when different methodologies are used., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

During a pre-purchase examination (PPE) there is always a debate about how clinical findings of the hoof different from ideal should be interpreted in relation to future lameness risk and/or unsuitability of the horse for the potential purchaser. The objectives of this study were to describe and compare external angular measurements, linear ratios and hoof capsule characteristics of non-lame and lame feet. Photographs of feet from 300 horses with foot pain and 25 non-lame horses were analysed. Hoof wall, heel and coronary band angles and hoof wall length and height, weight-bearing length, coronary band length and height of the coronary band at dorsal and palmar locations were measured and expressed as linear ratios. Mean hoof wall, heel and coronary band angles were larger in lame compared with non-lame feet; only the ratio of dorsal to palmar coronary band heights and the shape of the coronary band were significantly different between lame and non-lame horses. Growth rings were divergent and horn tubules were non-parallel in lameness of >3 months. At a PPE, a larger ratio of dorsal to palmar coronary band heights in one limb may be indicative of previous lameness in that foot. Changes in coronary band shape and divergent growth rings and horn tubules would suggest a longer duration., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

The historical and clinical findings in 200 referred cases of equine sinus disease were reviewed retrospectively. Univariable and multivariable analyses were performed to detect significant differences in historical or clinical features between various categories of sinus disease. The causes of sinus disease were classified as subacute primary (less than two months duration) (n=52), chronic primary (more than two months duration) (n=37), dental (n=40), sinus cyst (n=26), traumatic (n=13) or mycotic sinusitis (n=7), sinus neoplasia (n=10), dental-related oromaxillary fistula (n=8) and intrasinus progressive ethmoid haematoma (n=7). The majority of sinus disorders were of chronic duration at the time of referral and most (including 97 per cent of chronic primary sinusitis cases) had not responded to previous antibiotic therapy and/or sinus lavage in some cases. Clinical signs included unilateral nasal discharge in most cases, including purulent or mucopurulent discharge in all horses with primary, dental and mycotic sinusitis. Haemorrhagic nasal discharge was a feature of traumatic sinusitis and intrasinus progressive ethmoid haematomas. Firm facial swellings and nasal airflow obstruction were features of sinus cysts and neoplasms. Ipsilateral lymphadenitis was a more prominent feature of sinus disease with active infections such as primary, dental or mycotic sinusitis.

Reasons for Performing Study: To improve the understanding of exercise related sudden death in Thoroughbred racehorses., Objectives: To describe the post mortem findings in cases of sudden death associated with exercise in 268 Thoroughbred racehorses., Methods: Gross and histological post mortem findings of 268 cases of sudden death were collated and reviewed. Cases originated from 6 racing jurisdictions around the world. Sudden death was defined as acute collapse and death in a closely observed and previously apparently healthy Thoroughbred racehorse, during, or within one hour after, exercise. Cause of death as determined by the attending pathologist was categorised as definitive, presumptive or unexplained and compared between the different populations. Cardiopulmonary lesions recorded at post mortem examination were compared between different populations., Results: Pathologists recorded a definitive cause of death in 53% (143/268) of cases. Major definitive causes of sudden death included cardiac failure, apparent pulmonary failure, pulmonary haemorrhage, haemorrhage associated with pelvic fractures or with idiopathic blood vessel rupture, and spinal cord injury. A presumptive cause of death was made in 25% (67/268) of cases and death remained unexplained in 22% (58/268) of cases. There were several statistically significant inter-population differences in the cause of death and in reporting of cardiopulmonary lesions., Conclusions: Sudden death can be attributed to a variety of causes. Causes of sudden death and the lesions found in cases of exercise-related sudden death are similar in different racing jurisdictions. However, the lesions are often not specific for the cause of death and determination of the cause of death is therefore affected by interpretation by the individual pathologist., (© 2010 EVJ Ltd.)

Reasons for Performing Study: There is little scientific evidence to support the premise that poor foot conformation predisposes to foot pain and lameness., Objectives: To determine relationships between external characteristics of the hoof capsule and angles of the distal phalanx; to determine variability in shape of the distal phalanx; and to investigate association between distal phalanx angles and the injury causing lameness., Materials and Methods: Feet were documented photographically and radiographically. Linear and angle measurements were obtained for the hoof capsule and distal phalanx and compared statistically. Horses were categorised according to injury group, and angles and linear ratios were compared between groups., Results: There was modest correlation between hoof wall and heel angles and angles of the distal phalanx. There was variation in shape of the distal phalanx. There was no significant association between injury type and angles of the distal phalanx, although there was a trend for the angle of the dorsal aspect of the distal phalanx with the horizontal to be smaller in horses with injuries of the podotrochlear apparatus or deep digital flexor tendon compared with other groups., Conclusions: There are variations in shape of the distal phalanx largely due to differences in orientation of the concave solar border and the solar border to the horizontal. Variations in shape of the distal phalanx were not accurately correlated with external characteristics of the hoof capsule. There were weak associations between injury groups and angles of the distal phalanx., Clinical Relevance: Further work is required to elucidate risk factors for foot-related lameness., (© 2010 EVJ Ltd.)

Background: Trilostane is a recognized treatment for canine pituitary-dependent hyperadrenocorticism (PDH); however, its efficacy in dogs with adrenal-dependent hyperadrenocorticism (ADH) is unknown., Objectives: To examine factors that might influence survival in the medical management of ADH, with particular emphasis on treatment selection., Animals: Thirty-seven animals referred to 4 centers over a period of 12 years that had been diagnosed with ADH and treated with either trilostane (22/37), mitotane (13/37), or both (2/37)., Methods: Retrospective analysis of clinical records., Results: There was no statistically significant difference between the survival times of 13 dogs treated only with mitotane when compared with 22 dogs treated only with trilostane. The median survival time for animals treated with trilostane was 353 days (95% confidence interval [CI] 95-528 days), whereas it was 102 days (95% CI 43-277 days) for mitotane. Metastatic disease was detected in 8 of 37 dogs. There was a significantly lower probability of survival for dogs with metastatic disease when compared with those without metastatic disease (P < .001)., Conclusions and Clinical Importance: The choice of medical treatment for ADH may not have a major effect on survival times. However, the presence of metastatic disease considerably decreases survival time regardless of the choice of medical treatment., (Copyright © 2011 by the American College of Veterinary Internal Medicine.)

Objective: To determine whether histopathologic characteristics of the osteochondral units of equine distal tarsal joints were associated with exercise history in horses without lameness., Sample Population: 30 cadaver tarsi from horses without lameness and with known exercise history were separated into 3 groups: nonridden, pasture exercise (group P); low-intensity, ridden exercise (group L); and high-intensity, elite competition exercise (group E)., Procedures: Standardized sites from the centrodistal and tarsometatarsal joints under went histologic preparation. A grading system was adapted to describe location, depth, and shape of lesions; cellular arrangement; organization at cartilage and subchondral bone (SCB) junctions; and organization of SCB. A high score signified a more severe pathological change than a low score. Exercise groups were compared by calculation of Spearman rank correlations., Results: In the centrodistal joint, lesions were present in groups L and E but only medially. Cellular arrangement scores were higher at the dorsomedial location in group P than in groups L and E. Groups L and E had higher scores than group P for the organization of the cartilage, SCB junctions, and SCB, with higher scores at the dorsomedial location. In the tarsometatarsal joint, lesions were evident across the whole joint surface, with more severe lesions located laterally in all 3 groups. Overall, group E had higher scores for cellular arrangement and SCB organization than groups P and L., Conclusions and Clinical Relevance: Ridden exercise may increase the risk of osteochondral lesions at distal tarsal sites predisposed to osteoarthritis relative to the risk with nonridden exercise.

Aim: To validate the use of digital audio recording and analysis for quantification of coughing in horses., Materials and Methods: Part A: Nine simultaneous digital audio and video recordings were collected individually from seven stabled horses over a 1 h period using a digital audio recorder attached to the halter. Audio files were analysed using audio analysis software. Video and audio recordings were analysed for cough count and timing by two blinded operators on two occasions using a randomised study design for determination of intra-operator and inter-operator agreement. Part B: Seventy-eight hours of audio recordings obtained from nine horses were analysed once by two blinded operators to assess inter-operator repeatability on a larger sample., Results and Conclusions: Part A: There was complete agreement between audio and video analyses and inter- and intra-operator analyses. Part B: There was >97% agreement between operators on number and timing of 727 coughs recorded over 78 h. The results of this study suggest that the cough monitor methodology used has excellent sensitivity and specificity for the objective assessment of cough in horses and intra- and inter-operator variability of recorded coughs is minimal., (Crown Copyright 2010. Published by Elsevier India Pvt Ltd. All rights reserved.)

Bone modelling and remodelling reduce the risk of fatigue fractures; the former by adapting bone to its loading circumstances, the latter by replacing fatigued bone. Remodelling transiently increases porosity because of the normal delay in onset of the formation phase of the remodelling sequence. Protracted intense loading suppresses remodelling leaving modelling as the only means of maintaining bone strength. We therefore hypothesized that race horses with fatigue fractures of the distal third metacarpal bone (MC3) will have reduced porosity associated with suppressed remodelling while continued adaptive modelling will result in higher volume fraction (BV/TV) at this site. Using high resolution peripheral quantitative computed tomography (HR-pQCT), we measured the distal aspect of the MC3 obtained at postmortem from 13 thoroughbred race horses with condylar fractures of the MC3 (cases), 8 horses without fractures (training controls), 14 horses with a fracture at another site (fractured controls) and 9 horses resting from training (resting controls). Porosity of the subchondral bone of MC3 was lower in cases than resting controls (12±1.4% vs. 18±1.6%, P=0.017) although areas of focal porosity were observed adjacent to fractures in 6/13 horses. BV/TV of the distal metacarpal epiphysis tended to be higher in horses with condylar fractures (0.79±0.015) than training controls (0.74±0.019, P=0.070), but also higher in controls with a fracture elsewhere (0.79±0.014) than the training controls (0.74±0.019, P=0.040). BV/TV was higher in horses over three years of age than those aged two or three years (0.79±0.01 vs. 0.74±0.01, P=0.016). All metacarpal condylar fractures occurred within focal areas of high BV/TV. We infer that intense training in equine athletes suppresses remodelling of third metacarpal subchondral bone limiting damage repair while modelling increases regional bone volume in an attempt to minimise local stresses but may fail to offset bone fragility., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Reasons for Performing Study: Increased radio-isotope uptake (IRU) in the subchondral bone of the plantaro-lateral condyle of the third metatarsus (MTIII) is a commonly reported scintigraphic finding and potential cause of lameness in UK Thoroughbred racehorses in training and has not been fully documented., Objectives: To characterise lameness attributable to IRU of the subchondral bone of MTIII, compare the scintigraphic findings of these horses with a normal population and evaluate the use of scintigraphy as an indicator of prognosis., Hypothesis: IRU will be in significantly higher in horses with subchondral bone injury and will be related to prognosis and future racing performance., Methods: Data were analysed from 48 horses in which subchondral bone injury of the plantaro-lateral condyle of MTIII had been diagnosed using nuclear scintigraphy and that met the inclusion criteria. Data recorded included age, sex, trainer, racing discipline, lameness assessment, treatment regimes, radiographic and scintigraphic findings, response to diagnostic analgesia where performed and racing performance pre- and post diagnosis. Region of interest (ROI) counts were obtained for the plantar condyle and the mid diaphysis from the latero-medial view, the ratio calculated and then compared with a control group of clinically unaffected horses., Results: The mean condyle mid-diaphysis ROI ratio was significantly (P<0.001) higher in the affected population and with positively correlation (P = 0.024) with the level of lameness. The presence of radiographic findings had no significant effect on the ROI ratio., Conclusion: Subchondral bone injury of the plantar lateral condyles of MTIII is a significant cause of lameness in UK Thoroughbred racehorses. Nuclear scintigraphy is a useful diagnostic imaging modality in the detection of affected horses but is a poor indicator of prognosis for the condition., Potential Relevance: Better understanding of the clinical manifestations, diagnosis of and prognosis for subchondral bone injury will benefit the Thoroughbred industry in the UK.

Reason for Performing Study: Catastrophic biaxial proximal sesamoid bone fractures (PSBF) have not yet been described in detail in the UK racing population., Objectives: To determine the incidence and relative risk (RR) of PSBF in different types of racing in the UK; and to describe horse-level characteristics and racing histories of horses sustaining these injuries., Methods: Distal limbs were collected from all racehorses suffering catastrophic fractures during racing at all 59 racecourses in the UK, in a prospective study from February 1999 to December 2004. Post mortem investigation identified the anatomical location and type of fracture. Horse, racing history, race and racecourse details were obtained. Characteristics of the horses that sustained PSBF were described. The incidence and RR of PSBF in the different types of racing in the UK were calculated., Results: Thirty-one horses suffered PSBF during the study period. The incidence of PSBF in all types of race was 0.63 per 10,000 starts (31/494,744). The incidence was highest in flat races on all weather surfaces (1.63 per 10,000 starts: 12/73,467; RR = 4.4 when compared to turf flat racing). Affected horses had an average age of 5.6 years and had started a mean of 28 races at the time of fracture., Conclusion and Potential Relevance: There is a strong association between type of racing surface and PSBF. Horses competing in flat races on all weather surfaces have an increased risk of PSBF. These fractures appear to happen in experienced horses with several starts, with few fractures occurring within the first season of racing. Further research should focus on identification of underlying pathology of these fractures. Epidemiological studies aimed at the identification of risk factors for PSBF in the UK racing population would require a large number of cases acquired over many years given the relatively low incidence of PSBF.

Reasons for Performing Study: There is limited information regarding the number of races and the period for evaluation of outcome which is critical for assessment of SDF tendonitis treatments., Objective: To evaluate the re-injury rate and racing performance of Thoroughbred racehorses that sustain SDF tendonitis in relation to matched controls in terms of number of races post treatment and maximum racing performance ratings before and after injury., Study Design: Clinical records and racing histories of 401 racehorses with a first occurrence of SDF tendonitis diagnosed by ultrasonography. Controls were of the same age, sex and were horses training in the same establishment at the time of injury as the case horses and where the trainer reported that the horse had not had a previous SDF tendon injury or treatment., Results: Eighty percent of both case and control horses returned to racing after the date of injury, and the re-injury proportion within 3 years of treatment was 53%. The difference in Racing Post Rating((max)) (RPR((max))) and the Racing Post Rating in the race immediately before the treatment date was significantly smaller in case horses (mean = 9.6 lbs; range = 0-75) compared to control horses (mean = 17.0 lbs; range = 0-79). No significant decrease in RPR((max)) was noted post injury. No difference between case and control horses was found for return to racing and racing 3 times, but control horses were significantly more likely to compete 5 races post treatment date than case horses., Conclusion and Clinical Relevance: Injury was associated with an individual's pre-injury maximum performance level and return to racing and completion of 3 races are not useful indicator of the outcome of horses with SDF tendonitis. The assessment of the outcome of horses with an SDF injury in a population of racehorses using the number of races post injury requires a minimum of 5 races post injury to be a useful indicator. Further, a re-injury proportion in a population of horses in training for 3 years post treatment.

The aim of this study was to describe the prevalence of illness and lameness at different anatomical sites in registered United Kingdom dressage horses and to identify risk factors for lameness. A questionnaire was sent to all 11,363 registered members of British Dressage in 2005, with one questionnaire assigned per horse. Four multivariable logistic regression models were developed for each section of the questionnaire. A final mixed effects logistic regression model was developed which combined the results from all prior models. Owners reported that 33% of horses had been lame at some time during their career, with 24% of these within the previous 2 years. A number of factors were associated with the occurrence of lameness in the last 2 years, including age, height, indoor arenas, horse-walkers, lunging (as protective), back problems, arenas that become deeper in wet conditions and sand-based arenas. These factors were included as variables in a final model to provide information for selection of horses, development of safer arenas and more effective training regimens to minimise the onset of lameness., (Copyright 2009 Elsevier Ltd. All rights reserved.)

Objectives: To investigate whether microfractures and alterations in the trabecular bone area are associated with catastrophic bi-axial proximal sesamoid bone fractures (PSBF)., Methods: Proximal sesamoid bones (PSB) from 10 racehorses with PSBF and from 10 control racehorses without musculoskeletal injury were examined using the bulk basic fuchsin method. Bone histomorphometric and microfracture analysis was performed, and cases and controls compared using two-sample t-test, paired t-test, and Mann-Whitney U test., Results: There was no significant difference in the microfracture density and the trabecular bone area between bones from case and control horses, and between fractured and non-fractured bones in case horses., Clinical Relevance: Microfracture density was low in the areas of the PSB examined. Microfracture density was not significantly different between groups, indicating that propagation of micro-cracks is an unlikely predisposing pathologic alteration in PSBF in British racehorses. There was no significant difference in the bone surface area between groups, which one would expect if modelling, adaptation and an increase in bone density were associated with PSBF fracture in the case horses. Therefore, PSBF in the British racehorse does not appear to be associated with microfractures of the trabecular bone of the PSB. The PSB fractures might represent an acute monotonic fracture; however, the aetiology of the fractures remains unknown with additional research required.

Regulation of pH homeostasis in the equine lung is poorly understood. Measurement of exhaled breath condensate (EBC) pH provided a simple, highly repeatable and noninvasive method for the longitudinal investigation of changes in airway pH in response to environmental changes. Stabling of horses was found to lead to a small (approximately 100-200 parts/billion) but significant (P < 0.001) increase in ambient ammonia concentration when compared to pasture. This increase in exposure to ambient ammonia concentration was associated with significant (P = 0.002) increases in EBC pH and exhaled ammonia (P = 0.013). Stable feed/bedding management type had no effect on EBC pH or exhaled ammonia concentration, while ambient ammonia concentration was influenced by stable management type.

OBJECTIVE-To investigate effects of exercise on hyaline cartilage (HC), calcified cartilage (CC), and subchondral bone (SCB) thickness patterns of equine tarsi. SAMPLE POPULATION-30 tarsi from cadavers of horses with known exercise history. PROCEDURES-Tarsi were assigned to 3 groups according to known exercise history as follows: pasture exercise only (PE tarsi), low-intensity general-purpose riding exercise (LE tarsi), and high-intensity elite competition riding exercise (EE tarsi). Osteochondral tissue from distal tarsal joints underwent histologic preparation. Hyaline cartilage, CC, and SCB thickness were measured at standard sites at medial, midline, and lateral locations across joints with a histomorphometric technique. RESULTS-HC, CC, and SCB thickness were significantly greater at all sites in EE tarsi, compared with PE tarsi; this was also true when LE tarsi were compared with PE tarsi. At specific sites, HC, CC, and SCB were significantly thicker in EE tarsi, compared with LE tarsi. Along the articular surface of the proximal aspect of the third metatarsal bone, SCB was thickest in EE tarsi and thinnest in LE tarsi; increases were greatest at sites previously reported to undergo peak strains and osteochondral damage. CONCLUSIONS AND CLINICAL RELEVANCE-Increased exercise was associated with increased HC, CC, and SCB thickness in mature horses. At sites that undergo high compressive strains, with a reported predisposition to osteoarthritic change, there was increased CC and SCB thickness. These results may provide insight into the interaction between adaptive response to exercise and pathological change.

Measurement of hydrogen peroxide (H(2)O(2)) concentration and pH in exhaled breath condensate (EBC) is useful for detection and monitoring of asthma in humans. In contrast, limited information on the use of these parameters for the investigation of lower airway inflammation (LAI) is available for horses. Aims of the current study were to investigate the intra- and inter-day variations of EBC H(2)O(2) concentration and pH in horses and establish any relationship(s) with LAI. Both intra- and inter-day variability of EBC H(2)O(2) concentration were large, while those of pH were small. No significant difference in the intra-day or inter-day H(2)O(2) concentrations or pH measurements were found in control or LAI horses, except for inter-day H(2)O(2) concentration in horses with LAI (p=0.019). There was no significant difference in EBC pH or H(2)O(2) concentration between control and LAI horses, however a trend for a reduced pH in horses with LAI was observed.

Reasons for Performing Study: The prevalence (up to 93% in Thoroughbred racehorses) and severity of equine gastric ulceration syndrome (EGUS) have been correlated with the type of training and associated management practices. However, there have been few reports to confirm these findings in nonracehorses in Europe., Objectives: To describe the prevalence, anatomical distribution, severity and number of gastric ulceration lesions in a population of Danish pleasure horses; and to investigate differences for groups based on age, breed type and workload., Methods: A total of 201 horses not in active race-training, age 7 months-27 years, were evaluated, representing 23 different stables from all 5 regions of Denmark. These horses were considered to be healthy by the owner and not on veterinary treatment for EGUS. Endoscopically observed ulcer lesion scores were based on the number present (0-4) and severity (0-5). The presence or absence of ulcers in the glandular and/or nonglandular regions of the stomach was recorded and which site the most severe ulcers were found., Results: The prevalence of EGUS severity score > or = 2 was 53%. The most severe lesions were commonly observed at the margo plicatus. Although older horses were not more likely to be affected by clinically significant EGUS they were more likely to have lesions in both the glandular and nonglandular regions. Differences in location of EGUS lesions were identified in different age groups, breed types and in horses exposed to different levels of work., Conclusion and Potential Relevance: This study confirms that gastric ulceration can be prevalent in a group of apparently clinically normal horses, not in intensive work. Further investigation of reasons for differences in EGUS location between different populations may aid toward the development of novel preventive measures.

Reasons for Performing Study: The prevalence (up to 93% in Thoroughbred racehorses) and severity of equine gastric ulceration syndrome (EGUS) has been associated with type of training and differing management practices. However, there have been few studies to confirm these findings in nonracehorses in Europe., Objectives: To investigate the prevalence of EGUS in a population of Danish horses, during winter when the horses had been housed and fed for at least 8 weeks and to analyse the influence of feed, work level and environment on the risk of EGUS of > or = grade 2 in severity., Methods: A total of 201 horses, not in active race-training, were evaluated, representing 23 different stables from all 5 regions within Denmark. All horses were considered to be healthy and not on medical treatment for EGUS. Endoscopically observed ulcer lesion scores were based on the number present (0-4) and severity (0-5). Univariate and multivariable mixed effects logistic regression models were developed using EGUS score as the dependent variable. An ulceration severity score of > or = 2 was regarded as being clinically significant. Separate models were developed for horses with ulcers in either the glandular or nonglandular regions of the stomach graded > or = 2 (EGUS > or = 2) and for those horses that had nonglandular ulcers graded > or = 2 (NG > or = 2)., Results: In this population, 53% (107/201) of horses were graded as having EGUS > or = 2 with 95 (47%) horses having NG > or = 2. Three variables were significantly (P<0.05) associated with EGUS > or = 2: straw being the only forage available; exceeding 2 g/kg bwt of starch intake/day or >1 g/kg bwt/meal; and water not being available in the turn out paddock. Risk of NG > or = 2 significantly increased when straw was the only forage available, 1 g/kg bwt of starch/meal was exceeded, water was not available in the turnout paddock and the interval between forage feeding was >6 h., Conclusion and Potential Relevance: This study has confirmed that components of the diet, readily modifiable, may have an important impact on the risk of EGUS in the nonracehorse. Differences in the multivariable models produced for all ulcers and nonglandular ulcers support differences in the aetiology of ulcers in different locations of the stomach.