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• Speed, distance and time metrics tend to increase in accordance with level of play, also typically showing a concomitant reduction in variability • Women's Polo is comparable to 0– and 6–goal Polo, when comparing within-tournament measures and accompanying variability • Polo, irrespective of level, shows a high degree of between tournament variability. This is driven by within-subject variability which exceeded that of between-subject variability. • Z-scores are a convenient and useful method for capturing and displaying between tournament variability. This paper provides exemplar boundaries for practitioners considering this approach in Polo. The external work, as measured by global positioning systems, undertaken by Polo ponies during tournament play has been well-described across Polo of varying levels in both Open and Women's Polo. However, the variability within these data have not been thoroughly examined. Understanding the variability within these data between players (within-tournament variability) and between tournaments allows a deeper understanding of expected Polo performance and can inform coaching and tactical decisions, as well as aid in longitudinal horse development and comparison to other equestrian disciplines. The present paper captured data from 618 chukkas of Polo, in levels ranging from 0– to 16–goal and Women's Polo, across three New Zealand Polo seasons. Standard error and coefficient of variation were calculated to assess within-tournament variability; between-tournament variability was assessed via median percentage difference and Spearman's rho correlation coefficients. Playing duration, speeds (average and maximum) and distance metrics (total and standardized speed zones) typically increase with level of Polo play, with a concomitant reduction in within-tournament variability also seen. Nought (0–), 6–goal and Women's Polo show comparable within-tournament measures and associated variability. Polo, shows a high degree of between-tournament variability as within-player variability often exceeds that of between-player variability, affecting mathematical interpretations of reliability. Z-scores are a convenient alternative method for capturing and displaying between-tournament variability for the examined parameters, facilitating comparing across tournaments and seasons. Exemplar boundaries for this approach in Polo are provided. [ABSTRACT FROM AUTHOR]

This article utilizes data from the complete set of U.S. thoroughbred 2-year-old in-training sales held in 2013 and estimates the determinants of prices for 1806 two-year-old thoroughbreds. The results reveal that the time in which these prospective racehorses run a standardized distance is the most statistically significant determinant of market price. Other individual horse characteristics, pedigree quality variables and sale quality are also found to be price determinants. An additional result of interest is the significant premium buyers are willing to pay for horses by sires of unknown quality. [ABSTRACT FROM AUTHOR]

This article presents an analysis examining the wither height growth curves of 33 Thoroughbred horses from birth to maturity. The growth curve of each animal was analyzed, and the mature height was determined. Having established each animal's mature height, the growth curves were then normalized using the individual mature height and gestation length. A birth ratio (Brh) was established using the length of gestation divided by the fraction of maturity at birth (Fbh), and this value was found to be nearly identical for all horses in the study, indicating that the growth of each horse was very similar in normalized time. A relationship was developed predicting Fbh as a function of birth height, gestation time, and the animal's sex, and a procedure is presented to estimate an animal's mature height based on Fbh from the developed expression. The estimates of mature size were reasonable in most instances, and comparisons are shown indicating the efficacy of the predicted values compared to the values of mature wither height found from the growth curve regressions. [ABSTRACT FROM AUTHOR]

The first aim of this study was to analyze the behavioral traits and heart rate (HR) parameters in Thoroughbreds soon after the horses had finished their racing careers. The second aim was to select those traits, from those previously analyzed, which that would indicate the horses' further suitability for equestrian sports. The study was performed on 25 two-year-old Thoroughbred mares and geldings that had finished their racing careers. An initial observation was made by a jockey on the racing track. The first test evaluation was carried out on the 10th day after their return from the track to their home studs and the next 2 evaluations took place 1 and 2 months after the first assessment. The last (verifying) evaluation was performed 12 months after the first test evaluation. Between the first and last assessments, the horses were systematically trained to prepare them for equestrian sports. The first 3 assessments were based on behavioral observations and HR parameters. The verifying examination of a horse's suitability for recreational purposes with regard to its behavior was performed by a test rider. The results showed that it was possible to initially assess the suitability of a Thoroughbred for recreational purposes according to 2 groups of attributes: behavioral and HR and heart rate variability parameters. The behavioral analysis focused on the behavior of a horse when a person enters the box and when a horse faces an unknown object. HR and heart rate variability parameters assessed included HR measurements when a person enters the box and during bridling and root mean square of successive differences measurements when a person enters the box and when a horse faces an unknown object. This second assessment occurred 1 month after a horse returned from the racing track to the mother stud. As indicated by the results, 1 month is the critical period needed to adjust to new circumstances after being on the racetrack. Earlier examination might not be accurate. [ABSTRACT FROM AUTHOR]

Reasons for performing study Outcomes associated with arthrodesis of the proximal interphalangeal ( PIP) joint in Quarter Horses used for Western performance activities are well documented but little is known regarding outcomes for other types of horses. Objectives To identify factors associated with outcomes, including breed and activity, after arthrodesis of the PIP joint in Warmbloods, Thoroughbreds and Quarter Horses. Study design Retrospective case series. Methods Surgical case records of 82 Quarter Horses principally engaged in Western performance and Thoroughbred or Warmblood breeds principally engaged in showing, showjumping and dressage, with arthrodesis of the PIP joint were reviewed. Arthrodesis was performed with either 3 transarticular cortex bone screws placed in lag fashion, a dynamic compression plate ( DCP) with 2 transarticular cortex bone screws placed in lag fashion, or a locking compression plate ( LCP) with 2 transarticular cortex bone screws placed in lag fashion. Demographic data, clinical presentation, radiographic findings, surgical technique, post operative treatment and complications were recorded. Long-term follow-up was obtained for all 82 horses. Results Osteoarthritis of the PIP joint was the most common presenting condition requiring arthrodesis, which was performed with either the 3 screw technique (n = 41), DCP fixation (n = 22), or LCP fixation (n = 19). Post operatively, 23/31 (74%) Warmbloods/Thoroughbreds and 44/51 (87%) Quarter Horses achieved successful outcomes. Thirteen of 23 (57%) Warmbloods/Thoroughbreds and 24 of 38 (63%) Quarter Horses, used for athletic performance, returned to successful competition. Within this subgroup of horses engaged in high-level activity, regardless of breed type, horses undergoing hindlimb arthrodesis were significantly more likely to return to successful competition (73%; 33/45) than those with forelimb arthrodesis (25%; 4/16, P = 0.002). Conclusions Arthrodesis of the PIP joint in Warmbloods/Thoroughbreds and Quarter Horses results in a favourable outcome for return to their intended use and athletic competition. [ABSTRACT FROM AUTHOR]

Reasons for performing study Sesamoiditis is a common radiological finding in yearling Thoroughbreds. The condition is believed to be associated with suspensory ligament branch injury ( SLBI), which is known to affect racing performance. The presence of subclinical suspensory ligament branch change ( SSLBC) in untrained yearlings has not been investigated. Associations between sesamoiditis, SSLBC and subsequent SLBI would allow more accurate prognoses to be made regarding the development of SLBI. They could also provide opportunity for intervention and prevention of SLBI. Objectives To test our hypotheses that untrained yearling Thoroughbreds with sesamoiditis would be more likely to have ultrasonographic findings of SSLBC and those horses with concurrent sesamoiditis and SSLBC would be more likely to develop clinical suspensory ligament branch injury with training. Study design Prospective, cohort, observational study. Methods Yearling Thoroughbreds located at a single training centre were evaluated at the onset of their training careers and for the next 9 months. Radiographic and ultrasonographic examination of bilateral forelimb proximal sesamoid bones and suspensory ligament branches was performed. Results Fifty horses were eligible, resulting in 200 forelimb sesamoid/suspensory ligament branch pairs. A significant relationship existed between possibly significant ( PS) sesamoiditis and PS SSLBC (P<0.001). The odds ratio of sesamoids with PS sesamoiditis also demonstrating concurrent PS SSLBC was 5.1 (95% confidence interval 2.68-9.70, P<0.001). A significant relationship also existed between the concurrent presence of PS sesamoiditis and PS SSLBC and the subsequent development of clinical signs of SLBI (P<0.001, odds ratio 11.7, 95% confidence interval 4.1-33.4). Conclusions The associations identified in this study highlight the importance of ultrasonographic examination of suspensory ligament branches in horses with PS sesamoiditis. This information should allow more accurate prognostic advice regarding potential SLBI development and also provide opportunities for intervention and prevention of clinical SLBI. The Summary is available in Chinese - see Supporting information [ABSTRACT FROM AUTHOR]

Training is essential to prepare the body for intense changes occurring in athletic performance. The effect of training depends on the duration, type, frequency, and intensity of athletic training. The aim of this study was to evaluate the profile of proteins, metabolites, minerals, and enzymes of polo horses in training and those that participate regularly in official competitions. Blood samples were collected from 82 thoroughbred horses. A single collection was performed in the morning, before training the horses. They were divided into two groups: group 1 consisted of training horses, which have not yet participated in polo, whereas group 2 consisted of professional horses that regularly participated in the sport. Each sample was analyzed for levels of albumin, calcium, total cholesterol, creatinine, alkaline phosphatase, phosphorus, gamma glutamyl transferase, total protein, aspartate aminotransferase, alanine aminotransferase, triglycerides, HDL, urea, and magnesium. Every element analyzed was within the normal physiological limits. By comparison of the two groups, it was statistically significant for lactate, aspartate aminotransferase, alkaline phosphatase, gamma glutamyl transferase, urea, creatinine, phosphorus, and potassium. Biochemical variation was observed between groups 1 and 2, it was concluded that this was relative to the physical condition of each animal. [ABSTRACT FROM AUTHOR]

In this study, we investigated the effect of aging on biochemical markers in serum obtained from Thoroughbred horses (n = 30) and ponies (n = 15). Aging was observed to have an effect on albumin, total bilirubin, thyroxine, and iron levels. The triglyceride concentration in ponies was found to be significantly higher than in Thoroughbreds. Furthermore, an age-related increase in triglycerides was only observed in ponies. There was no aging effect on diacron-reactive oxygen metabolites and biological antioxidant potential concentration. A significant negative correlation between age and bilirubin, known as a strong antioxidative substance, was obtained in both the Thoroughbred and pony groups. However, the distribution area of data was different due to higher bilirubin concentrations in Thoroughbreds. The serum iron levels were correlated with serum triglyceride levels in ponies. We propose that the metabolism of ponies differs from that of Thoroughbreds and that careful breeding and appropriate exercise are required for aging ponies. [ABSTRACT FROM AUTHOR]

Reasons for performing study Ambient temperature has been identified as a risk factor for exercise-induced pulmonary haemorrhage ( EIPH) in racing Thoroughbreds. This warranted a more expansive investigation of climatic conditions on the incidence and severity of EIPH. The impact of other variables such as the type of bit used, tongue ties and nonstandard shoes has not been reported and also warrant investigation. Objectives To examine the effect of various climatic variables as contributing risk factors for EIPH. Other previously uninvestigated variables as well as standard track and population factors will also be examined. Study design Cross-sectional study. Methods Thoroughbred racehorses competing at metropolitan racetracks in Perth, Western Australia were examined 30-200 min post race with tracheobronchoscopy. Examination took place at 48 race meetings over a 12 month period. Examinations were graded (0-4), independently by two experienced veterinarians. Univariable analyses were performed and variables with a P<0.25 were entered into a multivariable logistic regression analysis. The analysis was performed twice using the presence of blood ( EIPH grade 0 vs. grades ≥1) and EIPH grades ≤1 vs. EIPH grades ≥2 as dependent variables. Results Exercise-induced pulmonary haemorrhage was diagnosed in 56.6% of observations. Lower ambient temperature was significantly associated with EIPH grades ≥1 ( OR 0.95; 95% CI 0.93-0.98) and EIPH grades ≥2 ( OR 0.97; 95% CI 0.94-1.0). Bar shoes were significantly associated with EIPH grades ≥1 ( OR 6.35; 95% CI 2.17-18.54) and EIPH grades ≥2 ( OR 2.72; 95% CI 1.3-5.68). Increasing race distance was significantly associated with EIPH grade ≥1 and increasing lifetime starts was significantly associated with EIPH grade ≥2. Conclusions Ambient temperature is a risk factor for EIPH in Thoroughbred racehorses, with lower temperatures associated with increased risk. Bar shoes are a novel risk factor for EIPH in this population. [ABSTRACT FROM AUTHOR]

The objective was to describe the incidence of failure to finish a race in flat-racing Thoroughbreds in New Zealand as these are summary indicators of falls, injuries and poor performance. Retrospective data on six complete flat racing seasons (n = 188,615 race starts) of all Thoroughbred flat race starts from 1 August 2005 to 31 July 2011 were obtained. The incidence of failure to finish events and binomial exact 95% confidence intervals were calculated per 1000 horse starts. The association between horse-, rider- and race-level variables with the outcomes failure to finish, pulled-up/fell and lost rider were examined with a mixed effects Poisson regression model. A total of 544 horses failed to finish in 188,615 race starts with an overall incidence of 2.88 per 1000 horse starts (95% CI 2.64–3.12). The incidence of failure to finish horses across each race year showed little variability. In the univariable analysis race distance, larger field size, season, and ratings bands showed association with failing to finish a race. The overall failure to finish outcome was associated with season, race distance and ratings bands (horse experience and success ranking criteria). In the multivariable analysis, race distance and ratings bands were associated with horses that pulled-up/fell; season, apprentice allowances and ratings bands were associated with the outcome lost rider. The failure to finish rate was lower than international figures for race day catastrophic injury. Racing and environmental variables were associated with failure to finish a race highlighting the multifactorial nature of race-day events. Further investigation of risk factors for failure to finish is required to better understand the reasons for a low failure to finish rate in Thoroughbred flat races in New Zealand. [ABSTRACT FROM AUTHOR]

Identification of risk factors which are associated with severe clinical signs can assist in the management of disease outbreaks and indicate future research areas. Pregnancy loss during late gestation in the mare compromises welfare, reduces fecundity and has financial implications for horse owners. This retrospective study focussed on the identification of risk factors associated with pregnancy loss among 46 Thoroughbred mares on a single British stud farm, with some but not all losses involving equid herpesvirus-1 (EHV-1) infection. In a sub-group of 30 mares, association between pregnancy loss and the presence of five common Thoroughbred horse haplotypes of the equine Major Histocompatibility Complex (MHC) was assessed. This involved development of sequence specific, reverse transcriptase polymerase chain reactions and in several mares, measurement of cytotoxic T lymphocyte activity. Of the 46 mares, 10 suffered late gestation pregnancy loss or neonatal foal death, five of which were EHV-1 positive. Maternal factors including age, parity, number of EHV-1 specific vaccinations and the number of days between final vaccination and foaling or abortion were not significantly associated with pregnancy loss. In contrast, a statistically significant association between the presence of the MHC class I B2 allele and pregnancy loss was identified, regardless of the fetus/foal’s EHV-1 status (p = 0.002). In conclusion, this study demonstrated a significantly positive association between pregnancy loss in Thoroughbred mares and a specific MHC class I allele in the mother. This association requires independent validation and further investigation of the mechanism by which the mare’s genetic background contributes to pregnancy outcome. [ABSTRACT FROM AUTHOR]

Redditch was a champion thoroughbred who won many major jumps races in Australia before his death in 1935. In Australia, jumps racing (primarily steeplechasing and hurdling) is now confined to Victoria and South Australia, and is far less popular than it was in the 1930s. The latter part of the paper compares reaction to the death of Redditch with contemporary jumps racing debates. The paper explores what has changed since 1935 and what can be learned from the death of Redditch in relation to contemporary jumps racing. [ABSTRACT FROM AUTHOR]

The observation of locomotor activity and resting behavior is used to determine time budgets, which may give some indication for the assessment of horses' welfare concerning management and housing. The aim of this study was to investigate total locomotor activity (TLA) daily rhythm in athletic horses (Thoroughbred, Standardbred, and Italian Saddle), with special attention to the intrasubject and intersubject variabilities. Ten subjects for each breed were divided into two subgroups, one housed in box and one housed in paddock. TLA was recorded for 10 consecutive days by mean of an activity data logger, Actiwatch Mini, applied at each horse by mean of a headstall. The obtained data were analyzed using the method of single cosinor. All horses, in all experimental conditions, showed a daily rhythm of TLA. On the obtained circadian parameters (mesor, amplitude, acrophase, and robustness), a multivariate analysis of variance was applied to investigate the effect of breed, housing conditions, and days of monitoring. It showed a statistically significant effect of breed on all circadian parameters; an effect of housing condition on mesor, amplitude, and robustness; and an effect of days of monitoring on acrophase and robustness. The analyses of intrasubject and intersubject variabilities indicate that organization of TLA daily rhythm in Standardbred and Jumper is characterized by greater accuracy of control within and between the individuals of a breed. In contrast, Thoroughbreds showed a high intrasubject and intersubject variability for all parameters studied, except for the intravariability of acrophase, denoting a different response to noxious stimuli that was observed not only among the subjects but also within the subject. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the prevalence of Malassezia species from the body skin and external ear canal of healthy horses. The samples were obtained by scraping the skin surface from the nose, groin and dorsum and swabbing from the external ear canal of 163 animals, and then incubated on sabouraud dextrose agar and modified Dixon agar. Malassezia species were isolated from 34.9% of horses. The percentages of Malassezia species were 64.3% for Arab, 35.7% for Persian, 35.4% for Thoroughbred and 27.1% for Turkmen breeds. The greatest abundance of Malassezia species was found in the external ear canal (47.7%, representing significant difference with other sites), followed by nose (26.3%), groin (15.8%) and dorsum (10.5%) ( P < 0.05). A total of 57 strains from six Malassezia species were detected with a frequency rate as follows: M. pachydermatis (33.3%), M. globosa (26.3%), M. sympodialis (14.1%), M. restricta (10.5%), M. obtusa (8.8%) and M. furfur (7%). The most common age-group affected was 1-3 years (59.4%). This study confirmed that cutaneous Malassezia microbiota in healthy horses varies by body site and age but not by breed and gender, representing M. pachydermatis as the most prevalent species on horse skin. [ABSTRACT FROM AUTHOR]

The case of the two year old thoroughbred filly presented here has been diagnosed with and treated for equine gastric ulceration syndrome (EGUS). The results of her examination are documented over a five month period. The patient was finally hospitalised with acute severe colic. Absence of chronic clinical problems common for pyloric stenosis can be attributed to the permanent antiulceration medication of the filly. The diagnosis of pyloric stenosis was made by exploratory laparotomy and confirmed by necropsy.

Thoroughbred jump racing sits in the spotlight of contemporary welfare and ethical debates about horse racing. In Australia, jump racing comprises hurdle and steeplechase races and has ceased in all but two states, Victoria and South Australia. This paper documents the size, geography, composition, and dynamics of Australian jump racing for the 2012, 2013, and 2014 seasons with a focus on debate about risks to horses. We found that the majority of Australian jump racing is regional, based in Victoria, and involves a small group of experienced trainers and jockeys. Australian jump horses are on average 6.4 years of age. The jump career of the majority of horses involves participating in three or less hurdle races and over one season. Almost one quarter of Australian jump horses race only once. There were ten horse fatalities in races over the study period, with an overall fatality rate of 5.1 fatalities per 1000 horses starting in a jump race (0.51%). There was significant disparity between the fatality rate for hurdles, 0.75 fatalities per 1000 starts (0.075%) and steeplechases, 14 fatalities per 1000 starts (1.4%). Safety initiatives introduced by regulators in 2010 appear to have significantly decreased risks to horses in hurdles but have had little or no effect in steeplechases. Our discussion considers these data in light of public controversy, political debate, and industry regulation related to jump horse safety. [ABSTRACT FROM AUTHOR]

Abstract: The experiment was conducted to estimate dietary threonine (Thr) requirement using plasma amino acid concentrations as a criterion in mature thoroughbreds. Four adult thoroughbreds were used, and a 4 × 4 Latin square design was used for four dietary Thr levels. Plasma Thr concentration was constant until 0.41%, and then increased rapidly with increasing dietary Thr levels. The Thr requirement was estimated to be 67% of lysine with plasma Thr concentration at four Thr levels. [ABSTRACT FROM AUTHOR]

• Treatments were administered following three quarters of coverings • Two thirds of post-covering treatments included intrauterine antibiotics • Over a third of mares without visible intrauterine fluid still received post-covering treatment • A third of mares required veterinary care for disease or injury during gestation • Half of mares received at least one non-reproductive medication during gestation The study aimed to (1) describe the use of reproductive therapeutics; (2) estimate the incidence of disease and injury; and (3) describe non-reproductive medications administered during pregnancy in Thoroughbred broodmares. A prospective birth cohort was established on seven farms across the UK and Ireland. Details of dams' signalment, breeding history, reproductive management during the breeding season(s) and veterinary-attended episodes of illness or injury and medication usage during gestation were retrieved retrospectively for 275 pregnancies in 235 mares over two breeding seasons. Results are reported at pregnancy-level of mares with data available. Preoestrus medications, ovulatory agents and post-covering treatments were administered to 55% (n = 85/155, 95% Confidence interval (CI) 47–62), 64% (n = 101/157, 95% CI 57–71) and 73% (n = 109/150, 95% CI 65–79) of mares respectively. Antibiotics were utilized in 69% (n = 75/109, 95% CI 60–77) of post-covering treatments. Of mares with no visible fluid on post-covering ultrasound, 37% (n = 24/65, 95% CI 26–49) still received treatment. Thirty-four percent (n = 70/203, 95% CI 28–41) of mares suffered at least one veterinary-attended episode of disease or injury, with conditions affecting the musculoskeletal system (23%, n = 46/203, 95%CI 17–29) and placentitis (5%, n = 10/203, 95% CI 3–9) most prevalent. Forty-seven percent (n = 95/203, 95% CI 40–54) of mares received at least one non-reproductive medication during gestation, antibiotics (25%, n = 51/203, 95% CI 20–31) and non-steroidal anti-inflammatory drugs (23%, n = 47/203, 95% CI 18–29) being most frequently prescribed. Post-covering treatments often included antibiotics and were sometimes given in the absence of fluid, highlighting a need to further understand therapeutic rationale. Disease occurrence and medication usage during gestation were frequent and warrant additional investigation. [ABSTRACT FROM AUTHOR]

• Levels of phosphorylated neurofilament heavy chain in clinically healthy and injured Thoroughbred racing horses were compared in a case-control study. • There was no significant association between the levels of phosphorylated neurofilament and the risk of catastrophic injury. • Association between Phosphorylated neurofilament heavy subunit in serum and putative risk factors for catastrophic injuries in Thoroughbred racing horses Neurofilaments are structural proteins that are concentrated in the body and axons of neurons. Damage to the neurons or axons as a result of trauma or infectious diseases leads to the release of neurofilaments into blood and cerebrospinal fluid (CSF). This case-control study was carried out to compare serum levels of phosphorylated neurofilament heavy chain (pNF-H) between clinically healthy Thoroughbred (TB) horses and TB horses that suffered catastrophic musculoskeletal injuries (cMSI), and to investigate the correlation between putative risk factors and serum concentrations of pNF-H in injured horses. Blood samples were collected from clinically healthy horses and from horses that suffered cMSI. The concentration of pNF-H in serum samples was determined using the Phosphorylated Neurofilament H Sandwich enzyme-linked immunosorbent assay kit. A total of 343 horses were enrolled in the study (148 cases and 195 controls). The median serum concentration of pNF-H for controls was 0.0 ng/ml and for cases was 0.07 ng/ml. No significant difference was observed between the 2 groups in racing. The number of lifetime starts was correlated with serum pNF-H concentration in case horses. The serum concentration of pNF-H was higher in case horses that experienced cMSI while training than while racing. The number of lifetime starts is a proxy measure for several risk factors related to cumulative exercise load during the career of racehorses. Measurement of serum concentrations of pNF-H in TB racehorses does not support the hypothesis that subclinical neurologic injury or conditions are associated with catastrophic injury of TB racehorses. [ABSTRACT FROM AUTHOR]

Background Decreased efficacy of antimicrobials and increased prevalence of multidrug resistance ( MDR) is of concern worldwide. Objectives To describe and analyze bacterial culture and antimicrobial susceptibilities from respiratory samples submitted from young horses (4 weeks to 3 years old). Animals Samples from 289 horses were submitted to a commercial laboratory. Methods A retrospective database search of submissions made to a New Zealand veterinary laboratory between April 2004 and July 2014. The results of in vitro susceptibility testing by Kirby-Bauer disc diffusion were described and tabulated for the major bacterial species isolated. Multiple correspondence analysis ( MCA) was used to describe the clustering of MDR isolates and selected demographic variables. Results Overall, 774 bacterial isolates were cultured from 237 horses, the majority of these isolates were gram-positive (67.6%; 95% CI 64.3-70.9%). Streptococcus spp. were the most common genus of bacteria isolated and were 40.1% (95% CI 36.6-43.5%) of the isolates cultured. Susceptibility of Streptococcus spp. to penicillin, gentamicin, and ceftiofur was >85%. Overall, gram-negative susceptibility to ceftiofur, tetracycline, and TMPS was <75%. MDR was defined as resistance to 3 or more antimicrobials, and was found in 39.2% of horses (93/237; 95% CI 33.0-45.5%). Conclusions and clinical importance Culture and susceptibility results have highlighted that MDR is an emerging problem for young horses in New Zealand (NZ), where a bacterial respiratory infection is suspected. This should be considered when prescribing antimicrobials, and emphasizes the need for submission of samples for culture and susceptibility. [ABSTRACT FROM AUTHOR]

Reasons for performing study Fracture of the metacarpal/tarsal condyle is usually preceded by prodromal pathology. Early recognition of injury is desirable to minimise the risk of serious breakdown; however, the clinical and diagnostic characteristics of unicortical condylar fractures have been poorly documented to date. Objectives To describe the clinical, imaging and outcome features of racehorses in first opinion practice diagnosed with short unicortical fracture of the metacarpal/tarsal condyle. Study design Retrospective case series. Methods All flat racehorses sustaining a unicortical condylar fracture while under the primary care of a single first opinion UK veterinary practice (2006-2013) were identified from imaging records and histories analysed for clinical presentation, lesion location, treatment, rehabilitation guidance and outcome. Results Forty-five cases were identified during the period of study. Forelimb injuries predominated (35/45, 77.8%). Mean age of cases was 3.4 ± 1.3 years. Palpable clinical abnormality referable to the fetlock region was not a feature. The majority (35/45, 77.8%) of injuries were diagnosed with radiography (flexed dorsopalmar/plantar projection), with the remainder requiring magnetic resonance imaging ( MRI) for diagnosis. Seven horses underwent surgery either at the time of original diagnosis or following reinjury. Twenty-eight of 30 horses (93.3%), not retired for unrelated reasons, returned to racing, with 5 (16.7%) conservatively managed horses sustaining reinjury at a median of 305 days. Misdiagnosis resulted in progression to catastrophic fracture in 2 cases. Conclusions Clinical findings associated with unicortical condylar fractures can be mild and appropriate diagnostic imaging is necessary for injury detection. Failure to detect injury can lead to catastrophic fracture. Most cases respond to conservative management and return to racing, but risk of reinjury merits consideration of surgery in selected cases. Veterinary vigilance and timely intervention has the potential to considerably reduce the incidence of complete condylar fracture of the fetlock in the racehorse. The Summary is available in Chinese - see Supporting information. [ABSTRACT FROM AUTHOR]

Reasons for performing study Peri-anaesthetic complications are relatively common in equine patients and further investigations are warranted to identify manageable risk factors. Objectives To report morbidity and mortality rates and identify associated risk factors for horses undergoing general anaesthesia, within a predominantly racing Thoroughbred ( TB) population. Study design Single centre retrospective observational study. Methods Anaesthetic and case records of all horses ≥12 months old undergoing general anaesthesia at Newmarket Equine Hospital between August 2010 and April 2012 were analysed, excluding emergency abdominal/dystocia procedures or traumatology cases with cardiovascular compromise. Mortality and morbidity rates were calculated and described. Uni- and multivariable analyses were used to investigate the relationship between the principal complication, post anaesthetic colic (PAC) and risk factors. Results A total of 1067 anaesthetic records of 1021 horses were included in the study; of these, 702 horses (65.8%) were TB, 169 (15.8%) developed a complication within 7 days of general anaesthesia and 10 (0.94%) died as a result. The most prevalent morbidity was PAC, 111 horses (10.5%) developed colic within 7 days of general anaesthesia. Thoroughbred horses (odds ratio [ OR] 2.93, 95% confidence interval [ CI] 1.73-4.96) and horses receiving sodium benzylpenicillin (Na BP) ( OR 2.77, 95% CI 1.69-4.50) were at increased risk of PAC. Conclusions Thoroughbred racehorses were identified as at increased risk of PAC in this study and might benefit from more critical evaluation of post anaesthetic gastrointestinal function. An alternative to the administration of Na BP for prophylactic antimicrobial therapy needs to be further investigated if its role in PAC is confirmed by other studies. [ABSTRACT FROM AUTHOR]

During the dissection of seven Thoroughbred (Tb) and two Thoroughbred derivative (TbD) horses (9) displaying the congenital malformation of C6 and/or C6 and C7; variations in the gross morphology of the Longus colli muscle were noted. In the absence of the caudal ventral tubercle (CVT) on C6 only, the insertion of the medial and ventral layers and thoracic portion of the L. colli muscle attached to the cranial ventral tubercle (CrVT) on C6. However, on transposition of the CVT from C6 to the ventral surface of C7, the medial and ventral layers, a single deep bundle, and thoracic portion of the L. colli muscle attached to the CrVT on C6 and the transposed CVT on C7. In the unilateral malformation, this placed a distinct asymmetry in the paired left-to-right longitudinal presentation and cross-sectional samples of the L. colli muscle. In the bilateral malformation, the CrVTs were longitudinally malaligned and the L. colli replicated the unilateral presentation to a lesser extent. In this presentation, asymmetry was noted in entheses patterns and articular process joints, implying abnormal mechanical load, as was confirmed in the cross sections. As the L. colli muscle has specific cybernetic roles linked to posture and locomotion, these anatomic variations imply dysfunction. Premortem examinations confirmed eight of the nine horses exhibited proprioceptive and neurologic dysfunction (stillborn not included). This raises questions as to the equilibrium of affected horses and therefore the safety in handling and riding such horses, as was found in this study. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess differences in serum protein expression profiles of Przewalski's ( Mongolian wild horse) and thoroughbred horses using proteome analysis. The serum proteins were separated by two-dimensional electrophoresis (2- DE) and five different gene products were identified. Proteins represented by the five spots were identified by matrix-assisted laser desorption ionization-time-of-flight ( MALDI- TOF) mass spectrometry ( MS)/ MS technology. The identities of all proteins were deduced based on their similarity to proteins in the human plasma protein database. Three proteins (a haptoglobin-2 alpha glycoprotein and two haptoglobin-2beta glycoproteins with different accession numbers) were downregulated in Przewalski's horse sera compared to thoroughbred horse sera. Moreover, two proteins (tetraspanin-18 and pM5) were upregulated in Przewalski's horses compared to thoroughbred horses. Haptoglobin-2 alpha and haptoglobin-2beta may serve as candidate molecules in future studies of inflammation, coagulation, immune modulation and pro-oxidant and antioxidant activity with consequential effects on the entire metabolism of the horse. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the correlation between front limb conformation and the development of superficial digital flexor tendon (SDFT) lesions in flat racing Thoroughbred horses. Ninety-three 4-year-old flat racing Thoroughbreds trained in the same training facility were included in the study; 66 horses were orthopedically sound, and 27 had a history of an SDFT injury. Four different radiographic images of the distal parts of both front limbs were taken from each horse. After testing the repeatability of 18 digitally measured parameters, these measurements were taken for all the animals. The possible effect of conformation on SDFT lesion development was assessed by analyzing the association between each measured variable and the sound and/or lesion status of the horses. Differences between the two groups for each parameter were analyzed using t statistics. Sound horses showed a greater proximal interphalangeal dorsal joint angle than horses with an SDFT lesion. A smaller distal width of the middle phalanx was also associated with fewer tendon lesions. However, none of the measured conformational parameters showed a strong association with the development of SDFT lesions. It appears that conformational traits of the distal parts of the forelimb of flat racing Thoroughbreds are not a major contributing factor to the development of SDFT injury if analyzed separately. [ABSTRACT FROM AUTHOR]

Radiographic abnormalities (RAs) in the proximal interphalangeal (pastern) joint have several manifestations and can cause concern in young horses intended for racing. Our objective in this retrospective study was to describe the appearance and prevalence of pastern RAs in young Thoroughbreds and compare the racing outcomes of cases with sibling controls. All radiographic reports of young Thoroughbred racehorses born in 2003–2007 read by veterinarians in one Lexington, Kentucky, practice were searched for pastern RAs. Pastern RAs are described, and the 2- and 3-year-old racing records of affected horses are compared with siblings. Pastern RAs were detected in 1.3% of weanling and yearling Thoroughbred horses examined. Radiographic abnormalities detected included shallow (≤3 mm) indentations in joint contour, dorsal osteophytes or axial palmar and/or plantar enthesophytes (≥3 mm), osseous fragments, and subchondral lucencies (≥4 mm). Horses with fragments in the pastern joint tended to be less likely to start a race at 2 years of age. Horses with fragments and subchondral bone cysts in the distal first phalanx tended to be less likely to start a race at 2 or 3 years of age than control siblings. The importance of some pastern joint RAs to performance can be overemphasized; however, some RAs have a tendency to be associated with poorer racing outcomes than sibling controls and may be considered when reviewing the radiographs of young Thoroughbred racehorses. [ABSTRACT FROM AUTHOR]

The purpose of this short report is to describe the influences on the pricing of Thoroughbred (TB) horses for the adult recreational riding market. Research into the association between horse breed and specific behaviors supports the view that some breeds are more reactive than others. There is anecdotal evidence that TBs may be more likely than other breeds to show traits that compromise rider safety. Having been bred for speed and reactivity, TBs may have reduced habituation tendencies. In addition, those that have raced may have had more training to accelerate than to decelerate and as such may be predisposed to uncontrollable flight responses. We examined data from advertisements to determine which descriptors influence the price of TBs (n = 220) entering the adult riding horse market. Linear regression analysis of log(price) revealed that variates such as a larger total sum of performance experience and bigger advertisements ( P < 0.001), all significantly increased the price set by vendors. The inclusion of trail riding in the advertisement had a detrimental influence on price ( P < 0.001). Dressage experience was associated with increased pricing ( P = 0.002). The inclusion of positive descriptive terms associated with safety had a rather smaller and less significant effect ( P = 0.012) on price. The average advertised price of $3,286 for a TB was significantly cheaper than the average advertised price of a non-TB horse ($7,384; P < 0.001). In contrast to the findings for the ponies and non-TBs previously reported using the same method, reassuring descriptors had a significant positive influence on price of TBs. These data confirm that TBs are valued differently to other breeds in the Australian adult riding horse market. [ABSTRACT FROM AUTHOR]

Reasons for performing study Recurrent laryngeal neuropathy ( RLN) causes airway obstruction and adversely affects racing performance in Thoroughbred racehorses. Prosthetic laryngoplasty ( PL) is the preferred treatment of RLN as it returns variables of airway mechanics to baseline. A number of materials have been evaluated as prostheses; however, the application of Lycra has not been rigorously investigated. Objective To evaluate the efficacy of PL using a Lycra prosthesis, in combination with transendoscopic, laser-assisted ventriculocordectomy, to restore racing performance in Thoroughbred racehorses with RLN. Study design Retrospective case series. Methods Medical records, preoperative and post operative racing performance indices from 78 Thoroughbred racehorses that underwent surgical treatment for RLN were evaluated. Medical records, preoperative and post operative racing performance indices were evaluated. Case history, post operative complications and PL failure were recorded. Racing performance was analysed using Beyer Speed Figures ( BSF), earnings and a performance index ( PI), with comparisons made between the 3 races before and after surgery. Factors associated with return to racing and racing performance were analysed. Results Eighty-two per cent (46/56) of horses that raced prior to surgery and 75% (15/20) of horses that had not raced prior to surgery competed in at least one race post operatively. Horses had a lower BSF and PI in the final race before surgery. Following surgery, PI and BSF values were restored to preoperative values in 73% and 78% of horses respectively. Surgical failure rate and immediate post operative complication rate were lower than, or comparable with, other reported prosthesis materials. Conclusions Thoroughbred racehorses with RLN have a good prognosis for racing successfully after PL using a Lycra prosthesis. The described surgical technique is associated with a low post operative complication rate and an increase in indicators of racing performance ( PI and BSF) post operatively. Lycra offers an attractive option for application as a prosthetic for PL with a low complication rate and similar efficacy to reported rigid prostheses. [ABSTRACT FROM AUTHOR]

Two variants in the equine myostatin gene ( MSTN), including a T/C SNP in the first intron and a 227-bp SINE insertion in the promoter, are associated with muscle fiber type proportions in the Quarter Horse ( QH) and with the prediction of race distance propensity in the Thoroughbred ( TB). Genotypes from these loci, along with 18 additional variants surrounding MSTN, were examined in 301 horses of 14 breeds to evaluate haplotype relationships and diversity. The C allele of intron 1 was found in 12 of 14 breeds at a frequency of 0.27; the SINE was observed in five breeds, but common in only the TB and QH (0.73 and 0.48 respectively). Haplotype data suggest the SINE insertion is contemporary to and arose upon a haplotype containing the intron 1 C allele. Gluteal muscle biopsies of TBs showed a significant association of the intron 1 C allele and SINE with a higher proportion of Type 2B and lower proportion of Type 1 fibers. However, in the Belgian horse, in which the SINE is not present, the intron 1 SNP was not associated with fiber type proportions, and evaluation of fiber type proportions across the Belgian, TB and QH breeds shows the significant effect of breed on fiber type proportions is negated when evaluating horses without the SINE variant. These data suggest the SINE, rather than the intron 1 SNP, is driving the observed muscle fiber type characteristics and is the variant targeted by selection for short-distance racing. [ABSTRACT FROM AUTHOR]

There are almost 9,500 full-time employees in Australia's thoroughbred horse breeding industry. During foaling, they can be exposed to bodily fluids and mucous membranes which may present risks for zoonotic disease. These risks can be mitigated through personal biosecurity strategies. The aim of this study was to identify which personal biosecurity strategies were more or less likely to be adopted by workers. Seventeen participants representing 14 thoroughbred breeding farms and three equine veterinary practices in Australia's largest thoroughbred breeding region trialed up to 16 stakeholder-nominated personal biosecurity strategies over the 2021 foaling season. The strategies encompassed personal protective equipment (PPE), zoonotic disease awareness, policies and protocols, supportive environments, and leadership. Strategy adoption was monitored through three repeated self-audit surveys designed around the Transtheoretical Model of change (TTM) and findings were reviewed in exit interviews. For all survey waves in aggregate, 13 strategies were practiced by at least 50.0% of participants. Participants were most likely to use a ready-made foaling box (98.0%), communicate the message that PPE usage is a personal responsibility (94.1%) and use ready-made PPE kits (88.2%). However, 31.4% had no intention of doing practice sessions and/or dummy runs for PPE use and 27.5% had no intention of using a buddy system on farm/practice to check use of PPE. Whilst these rates indicate workers' willingness to adopt and maintain personal biosecurity strategies, they also indicate capacity for more practices to be implemented more often. Overall, the findings highlight the need for personal biosecurity interventions to be sensitive to the demands of the annual thoroughbred breeding calendar, the size of the breeding operation and the availability of skilled staff., Competing Interests: Author JC is the owner-operator of Equine Specialist Consulting. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Thompson, Taylor, Mendez, Chicken, Carrick and Durrheim.)

In this study, genome-wide CNVs were identified using a total of 469 horses from four horse populations (Jeju horses, Thoroughbreds, Jeju riding horses, and Hanla horses). We detected a total of 843 CNVRs throughout all autosomes: 281, 30, 301, and 310 CNVRs for Jeju horses, Thoroughbreds, Jeju riding horses, and Hanla horses, respectively. Of the total CNVRs, copy number losses were found to be the most abundant (48.99%), while gains and mixed CNVRs accounted for 41.04% and 9.96% of the total CNVRs, respectively. The length of the CNVRs ranged from 0.39 kb to 2.8 Mb, while approximately 7.2% of the reference horse genome assembly was covered by the total CNVRs. By comparing the CNVRs among the populations, we found a significant portion of the CNVRs (30.13%) overlapped; the highest number of shared CNVRs was between Hanla horses and Jeju riding horses. When compared with the horse CNVRs of previous studies, 26.8% of CNVRs were found to be uniquely detected in this study. The CNVRs were not randomly distributed throughout the genome; in particular, the Equus caballus autosome (ECA) 7 comprised the largest proportion of its genome (16.3%), while ECA 24 comprised the smallest (0.7%). Furthermore, functional analysis was applied to CNVRs that overlapped with genes (genic-CNVRs); these overlapping areas may be potentially associated with the olfactory pathway and nervous system. A racing performance QTL was detected in a CNVR of Thoroughbreds, Jeju riding horses, and Hanla horses, and the CNVR value was mixed for three breeds.

It is in the horse racing industry's interest to understand all factors that impact performance to maintain the integrity of the sport. There is some evidence that the start of flat races can affect racehorse performance. However, limited research exists on the explicit effect that waiting at the start and inside starting stalls (also known as starting gates or barriers) has on racehorse finishing position. This study investigated how temporal, behavior and loading related factors associated with the period before the start of the race influences racehorse performance. A cross-sectional design evaluated performance of 546 horses across eight flat race days at Chelmsford City Racecourse in November and December 2020, using televised racing coverage. Time horses spent inside starting stalls, the use of loading aids and jockey behaviors were recorded. Notational analysis was used to determine how much horses sweat and their behavior before, during and after loading. Behavior was categorized using an ethogram adapted from previous published research recording conflict behavior in horses. Horses that spent under 50 s inside starting stalls were more likely to win (p < 0.05) or finish in the top three (p < 0.01). Those showing moderate adverse behavior before loading (p < 0.01) and no adverse behavior inside stalls (p < 0.05) were more likely to win and place first to third, respectively, although behavior during loading had no significant effect. Horses sweating to the point of foaming (p < 0.01) and requiring specialist loaders (p < 0.05) were more likely to win, although the use of other loading aids did not significantly affect performance. Jockeys that pushed their bodyweight forwards in the saddle during loading were significantly more likely to place first to fourth (p < 0.05). A horse's chance of placing first to third was reduced by 15% for every increase in drawn order (p < 0.01; CI:0.77–0.96) and by 59% when the horse spent over 50 s inside stalls (p < 0.05; CI:0.19–0.92). A horse's likelihood of placing decreased by 13% for every year of age (p < 0.05; CI:0.78–0.97) and by a further 17% for each additional horse in the field (p < 0.001; CI:0.00–0.83). Racehorses showing adverse behavior inside stalls were 52% less likely to place (p < 0.05; CI:0.00–0.48). This research demonstrates that the start of flat races can influence performance, highlighting the importance of warm-up protocols and starting gate training to optimise performance. With further longitudinal research, these findings could support adjustments to the rules of racing regarding the start to improve and maintain the integrity of horseracing in the UK. • Racehorse behavior at the start and in starting stalls affects race performance. • Horses inside starting stalls for a shorter time are more likely to win and place. • Willingness to load and loading aids do not seem to affect racehorse performance. • The amount horses sweat prior to racing affects subsequent finishing position. [ABSTRACT FROM AUTHOR]

An 8-year-old Thoroughbred mare presented with acute bilateral epistaxis. The mare showed no clinical signs other than cough and profuse bilateral epistaxis. Antibiotic therapy was instituted and a transtracheal wash was collected. Large numbers of inflammatory neutrophils and gram-positive cocci were reported in the tracheal wash. The antibiotic therapy was continued for 7 days at which time the mare appeared clinically normal. The mare was successfully bred and was confirmed pregnant. She was referred to a hospital when the epistaxis recurred. She was treated with another antibiotic, and thoracic radiographs were also taken which revealed a space occupying lesion. The mare foaled a live foal. She developed bilateral thickening of her limbs. The swellings were of boney consistency and affected all four legs, particularly the forelimbs. A diagnosis of pulmonary hypertrophic osteopathy was made. The mare was again sent for further investigation. The thoracic mass had increased in size from the first examination. A biopsy was collected by endoscopy which confirmed a neoplastic process. After deterioration in her condition, the mare was euthanized on humane grounds. An autopsy report revealed that the mare had approximately 80% of the left lung replaced by neoplastic tissue. The right lung contained many small nodular masses. There was an associated cardiomegaly. In this case, the development of periosteal proliferation in multiple metaphyses was secondary to an intrathoracic neoplastic mass. [ABSTRACT FROM AUTHOR]