Optimal speed in Thoroughbred horse racing.

The objective of this work is to provide a mathematical analysis on how a Thoroughbred horse should regulate its speed over the course of a race to optimize performance. Because Thoroughbred horses are not capable of running the whole race at top speed, determining what pace to set and when to unleash the burst of speed is essential. Our model relies on mechanics, energetics (both aerobic and anaerobic) and motor control. It is a system of coupled ordinary differential equations on the velocity, the propulsive force and the anaerobic energy, that leads to an optimal control problem that we solve. In order to identify the parameters meaningful for Thoroughbred horses, we use velocity data on races in Chantilly (France) provided by France Galop, the French governing body of flat horse racing in France. Our numerical simulations of performance optimization then provide the optimal speed along the race, the oxygen uptake evolution in a race, as well as the energy or the propulsive force. It also predicts how the horse has to change its effort and velocity according to the topography (altitude and bending) of the track.

Subjective and objective evaluations of horses for fit-to-compete or unfit-to-compete judgement.

At Fédération Equestre Internationale (FEI) competitions, horses undergo veterinary inspection for judgement of 'fit-to-compete'. However, FEI Veterinary Delegates (VDs) often differ in opinion. The aim of the present study was to evaluate intra- and inter-observer agreements of fit-to-compete judgement and compare these with objective gait analysis measurements. Twelve horses were evaluated by three experienced VDs and one veterinary specialist and video-recorded for re-evaluation later. Simultaneously, quantitative gait analysis measurements were acquired. Inter-observer agreement during live evaluations was fair (κ = 0.395, 58% agreement). Intra-observer agreement between live observations and videos at one and 12 months was 71% and 73% respectively. Sensitivity and specificity of motion symmetry measured with quantitative gait analysis system were 83.3% and 66.7% respectively, against the consensus of all observers as a reference. These findings might suggest that more VDs should be used to adequately judge fit-to-compete. Quantitative-gait-analysis may be useful to support decision making during fit-to-compete judgement.

Mare and stallion effects on blastocyst production in a commercial equine ovum pick-up-intracytoplasmic sperm injection program.

This study retrospectively examined the degree to which success within a commercial ovum pick-up (OPU)-intracytoplasmic sperm injection (ICSI) program varied between individual mares and stallions. Over 2 years, 552 OPU sessions were performed on 323 privately owned warmblood mares. For mares that yielded at least one blastocyst during the first OPU-ICSI cycle, there was a 77% likelihood of success during subsequent attempts; conversely, when the first cycle yielded no blastocyst, the likelihood of failure (no embryo) in subsequent cycles was 62%. In mares subjected to four or more OPU sessions, the mean percentage of blastocysts per injected oocyte was 20.5% (range 1.4-46.7%), whereas the mean number of blastocysts per OPU-ICSI session was 1.67 (0.2-4.2). Age did not differ significantly between mares that yielded good or poor results. The number of recovered oocytes per OPU was positively associated with the likelihood of success (P<0.001). Although there were considerable between-stallion differences, most stallions (14/16) clustered between 15.6% and 26.8% blastocysts per injected oocyte, and the number of blastocysts per OPU (mean 1.4; range 0.2-2.2) was less variable than among mares. In conclusion, although both mare and stallion affect the success of OPU-ICSI, mare identity and the number of oocytes recovered appear to be the most reliable predictors of success.

Application of embryo biopsy and sex determination via polymerase chain reaction in a commercial equine embryo transfer program in Argentina.

Embryo biopsy for fetal sexing has clinical application, but few reports are available of its use within an active embryo transfer program. We evaluated results on biopsy of 459 embryos over one breeding season. There were no significant differences in pregnancy rate between biopsied and non-biopsied embryos (72% vs 73%) or for biopsied embryos recovered at the centre (73%) compared with those shipped overnight (72%). However, the pregnancy rate decreased significantly in shipped embryos biopsied ≥20h after collection. Overall, 86% of biopsies provided a sex diagnosis. The likelihood of a positive genomic (g) DNA result was significantly higher for biopsies from large blastocysts (96%) than from smaller embryos (70-85%). In total, 38% of biopsies were positive for Y chromosome DNA (Y-DNA) and were diagnosed as male. Subsequently, 95% of Y-DNA-positive embryos were confirmed as male and 78% of Y-DNA-negative embryos were confirmed as female. The accuracy of prediction of female (Y-DNA negative) was significantly higher when the biopsy sample was probed for Y-DNA only compared with probing for both gDNA and Y-DNA. We estimate that by transferring only Y-DNA-negative embryos, 3% of potential female pregnancies may have been lost, and production of male pregnancies was reduced by 72%.

Effects of exercise on cations/anions in blood serum of English Thoroughbred horses / Efeito do exercício sobre cátions/ânions em soro sanguíneo de equinos da raça Puro-Sangue-Inglês

English Thoroughbred horses, are widespread in Mexico and due to the lack of data on their exercise physiology, it is important to conduct exercise tests in order to obtain information the effects of exercise on more essential cations/anions in blood serum, as these horses are submitted to constant efforts. The study was carried out with 150 blood samples of English Thoroughbred horses clinically healthy. The blood sample collection was performed during three periods: 1) rest, 2) 30min after exercise (speed race of 12km/h for 30min with no rest) and 3) 60min after exercise. Mean values were calculated for cations (sodium and potassium) and anions (chloride and bicarbonate). The resulting data set was analyzed using Gaussian distribution and descriptive statistics. Confidence intervals of 95% were established. The linear relationships between ions were quantified, and an analysis of variance was performed to compare the mean values between groups. The concentrations of the described analytes are consistent with values reported by international literature. The comparison between groups, revealed that during exercise, sodium ion did not show changes 30min after exercise and increase 60min after. Potassium ion showed increase 30min after exercise and decrease 60min after. Chloride ion showed a decrease 30min after exercise, to recover gradually 60min after. Meanwhile, bicarbonate ion showed increase 30min after exercise, decreasing slightly in the final stage. Negative correlation between bicarbonate ion and chloride ion were determined. It was concluded that exercise tests are useful for the determination of acid-base balance and osmotic balance, and their main role is to evaluate the athletic ability of horses.Considering that chloride ion excretion and metabolic adjustments of potassium ion and bicarbonate ion are superior to water loss, compared to the normal osmolarity of blood serum. The results found can be used to structure an adequate replacement program of electrolytes lost in sweat.(AU)

Equinos da raça Puro-Sangue-Inglês são difundidos no México e, devido à falta de dados sobre sua fisiologia do exercício, é importante fazer testes de exercício para obter informações sobre os efeitos do exercício em cátions/ânions mais essenciais no soro do sangue, pois esses equinos são submetidos a esforços constantes. O estudo foi realizado com 150 amostras de sangue de equinos Puro-Sangue-Inglês, clinicamente saudáveis. A coleta de sangue foi realizada em três períodos: 1) descanso, 2) 30min após o exercício (corrida de velocidade de 12km/h por 30min, sem descanso) e 3) 60min após o exercício. Os valores médios foram calculados para cátions (sódio e potássio) e ânions (cloreto e bicarbonato). O conjunto de dados resultante foi analisado utilizando-se distribuição gaussiana e estatística descritiva. Intervalos de confiança de 95% foram estabelecidos. As relações lineares entre os íons foram quantificadas, e uma análise de variância foi realizada para se compararem os valores médios entre grupos. As concentrações dos analitos descritos são consistentes com os valores relatados na literatura internacional. A comparação entre os grupos revelou que, durante o exercício, o sódio íon não mostrou alterações 30min após o exercício e aumentou 60min após. O potássio íon mostrou aumento 30min após o exercício e diminuiu 60min após. O cloreto íon mostrou uma diminuição 30min após o exercício, para recuperar gradualmente 60min depois. O bicarbonato íon mostrou aumento 30min após o exercício, diminuindo ligeiramente no estágio final. Correlação negativa entre bicarbonato íon e cloreto íon foi encontrada. Concluiu-se que os testes de exercício são úteis para a determinação do equilíbrio ácido-base e do equilíbrio osmótico, e seu principal papel é avaliar a capacidade atlética dos equinos. Considerando-se que a excreção de cloro íon e ajustes metabólicos de potássio íon e bicarbonato íon são superiores à perda de água, comparada à osmolaridade normal do soro sanguíneo,os resultados encontrados podem ser usados para estruturar um programa adequado de reposição de eletrólitos perdidos no suor.(AU)

Prevalence, radiographic resolution and outcomes of slab fractures of the third and central tarsal bones in juvenile Thoroughbred horses.

BACKGROUND: Veterinarians are required to interpret the significance of radiographic findings for sale, soundness and future racing performance of weanling and yearling Thoroughbreds. We investigated the prevalence and radiographic appearance of slab fractures of the third (T3) and central tarsal (Tc) bones. METHODS: Weanling and yearling horses with complete or incomplete T3 or Tc fracture were identified by searching a database of radiographs. The prevalence and radiographic appearance at initial diagnosis and after continued pasture turnout, as well as prognosis for racing, of fractures of T3 and Tc were determined. RESULTS: Fractures were identified in 186 tarsi (184 T3 fracture only, 1 Tc fracture only, 1 Tc and T3 fracture) of 157 horses (126 unilateral T3, 29 bilateral T3, 1 contralateral Tc and T3, 1 unilateral Tc and T3) from 7676 examinations. The prevalence of T3 and Tc fractures was 2.40 (95% CI 2.07, 2.76) and 0.04 (95% CI 0.01, 0.11) per 100 radiographic examinations respectively. Fractures were identified on the D556-65°MPlLO view and occurred by survey examination at 11.1 ± 1.3 months in 85.7% horses. At initial diagnosis, 84.3% of T3 fractures appeared incomplete and involved the distal articular surface. Fracture score improved (P < 0.001), and dorsal modelling (P < 0.001) and osteoarthritis score increased in the distal intertarsal joint (P < 0.001), but not the tarsometatarsal joint, between survey and repository examinations. Fractures healed by repository examination in 71.9% of tarsi if there was > 6 months between examinations. There was no difference in sale price, and horses with T3 fractures had fewer trials when 2 and 3 years old (P = 0.023), yet no difference in other parameters of racing success when 2 or 3 years old compared with controls. CONCLUSION: Tarsal slab fractures can occur in juvenile Thoroughbreds and most heal with continued pasture turnout of > 6 months. Further investigation is required to determine risk factors and before making firm conclusions regarding the optimal management, prognosis for racing and long-term soundness.

[Heart disease in sports horses: Current recommendations of the 2014 ACVIM / ECEIM consensus statement]. / Herzerkrankungen beim Sportpferd: Aktuelle Empfehlungen des 2014 ACVIM/ECEIM Consensus Statements.

INTRODUCTION: Heart murmurs and arrhythmias are common in horses. Assessment of their clinical relevance concerning health, performance, safety and longevity of sports horses is of highest importance. A comprehensive cardiovascular examination is crucial for diagnosis and assessment of the severity of disease. Recently, an expert panel of the American College of Veterinary Internal Medicine (ACVIM) and the European College of Equine Internal Medicine (ECEIM) developed a consensus statement containing recommendations for sports horses with heart disease. This article summarizes the most relevant recommendations for practitioners, considering the most common and most important cardiac disorders in adult sports horses. These include mitral, aortic and tricuspid insufficiency, ventricular septal defects, atrial fibrillation as well as supraventricular and ventricular arrhythmias. Despite the fact that most horses with cardiovascular disease maintain a sufficient performance capacity, regular evaluations are indicated in horses with clinically relevant disorders. Under certain circumstances, horses with moderate to severe structural disease, with persistent untreated atrial fibrillation and with certain ventricular arrhythmias might still be used by informed adult riders. Horses with complex ventricular arrhythmias, pulmonary hypertension or congestive heart failure must not be ridden or driven and should be retired.

INTRODUCTION: Chez le cheval, on rencontre fréquemment des souffles cardiaques et des arythmies. L'appréciation de l'importance clinique de ces découvertes par rapport à la santé, au potentiel de performance, à la sécurité et à l'espérance de vie chez les chevaux de sport est une priorité. Un examen cardiovasculaire complet est essentiel pour atteindre ce but et pour estimer la gravité de l'affection. L'American College of Veterinary Internal Medicine (ACVIM) et l'European College of Equine Internal Medicine (ECEIM) ont récemment engagé un groupe d'experts qui, dans une prise de position commune, a formulé des recommandations concernant les chevaux de sport atteints d'affections cardiaques. Le présent article résume les recommandations importantes pour les praticiens. On y prend en considération les affections cardiaques les plus fréquentes et les plus importantes chez les chevaux de sport adultes. Il s'agit des insuffisances mitrales, aortiques et tricuspides, des communications interventriculaires, des fibrillations atriales ainsi que des arythmies supraventriculaires et ventriculaires. Bien que la majorité des chevaux souffrant de pathologies cardio- vasculaires présentent des performances suffisantes, des contrôles réguliers sont indiqués chez les patients présentant des modifications cliniquement significatives. Les chevaux souffrant d'altérations structurelles d'importance moyenne à élevées, de fibrillations atriales persistantes non traitées ou de certaines arythmies ventriculaires peuvent, suivant les cas et après explication des risques encourus, continuer à être utilisés par des cavaliers adultes. Les chevaux présentant des arythmies ventriculaires complexes, de l'hypertension pulmonaire ou une insuffisance cardiaque congestive ne devraient pas être montés ou attelés.

Exercise induced pulmonary hemorrhage in horses: American College of Veterinary Internal Medicine consensus statement.

BACKGROUND: Published studies of exercise-induced pulmonary hemorrhage (EIPH), when assessed individually, often provide equivocal or conflicting results. Systematic reviews aggregate evidence from individual studies to provide a global assessment of the quality of evidence and to inform recommendations. OBJECTIVES: Evaluate evidence to determine: if EIPH adversely affects the health, welfare or both of horses; if EIPH affects the athletic capacity of horses; the efficacy of prophylactic interventions for EIPH; and if furosemide affects the athletic capacity of horses. ANIMALS: None. MATERIALS AND METHODS: Systematic review. A panel of 7 experts was formed to assess evidence in the peer reviewed literature addressing each of the 4 objectives. Methodology followed that of the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). Publications were assessed for quality of evidence by working groups of the panel, and a summary of findings was presented in tables. Recommendations were based on quality of evidence and were determined by a vote of the panel. RESULTS: Much of the evidence was of low to very low quality. Experimental studies frequently lacked adequate statistical power. There was moderate to high quality evidence that EIPH is progressive, is associated with lung lesions, that it adversely affects racing performance, that severe EIPH (Grade 4) is associated with a shorter career duration, that furosemide is efficacious in decreasing the incidence and severity of EIPH, and that administration of furosemide is associated with superior race performance. CONCLUSIONS AND CLINICAL SIGNIFICANCE: Strong recommendation that EIPH be considered a disease and a weak recommendation for use of furosemide in management of racehorses with EIPH.

Sudden death, aortic rupture in horses, literature review, case studies reported and risk factors / Morte súbita por ruptura da aorta em cavalos, literatura, estudos de casos relatados e fatores de risco

Sudden deaths of horses in multiple equestrian disciplines have been attributed to acute and chronic respiratory and cardiovascular diseases. The aim of this study was to perform a review of aortic rupture in horses analyzing, case studies and assessing risk factors. The literature has reported a total of 137 cases of aortic rupture in horses for 28 years (1986-2014), with approximately five horses dying of aortic rupture per year. Histopathologically, there are observed discrete macroscopic degenerative changes in the intima layer only in the aorta. The histological evaluation in the beginning portion of the aorta of the heart evidenced degenerative changes with loss of continuity and distribution of elastic fibers. Risk factors for the rupture of the aorta are: spontaneous rupture associated with hypertension, preexisting vascular injury (aneurysm), dilated or hypertrophic cardiomyopathy, copper levels in the endothelium, genetic factors such as inbreeding, toxicology or pharmacological factors. Aortic rupture shows similarity with pulmonary hemorrhage induced by exercise especially under the locomotors induced trauma theory of exercise that can induce pulmonary hemorrhage. In conclusion, degenerative changes to discrete elastic fiber of the intima of the aorta in the emergence of the heart seem to predispose the aorta wall rupture at the time of maximum blood pressure during exercise and the consequent collapse and athletic horses death...

As mortes súbitas de cavalos em várias provas equestres têm sido atribuídas a doenças respiratórias e cardiovasculares agudas e crônicas. O objetivo deste estudo foi efetuar uma revisão de literatura da ruptura da aorta em cavalos analisando estudos de caso e estabelecendo os possíveis fatores de risco. Na revisão da literatura no período de 28 anos (1986-2014) foram localizados 137 casos de ruptura da aorta em cavalos com aproximadamente cinco cavalos morrendo por essa causa por ano. Histologicamente, são observadas alterações macroscópicas discretas degenerativas na camada íntima da aorta. A avaliação histológica na porção inicial da aorta do coração evidencia alterações degenerativas com perda de continuidade e distribuição das fibras elásticas. Fatores de risco para a ruptura da aorta dos cavalos são: ruptura espontânea associada com hipertensão, lesão vascular pré-existente (aneurisma), cardiomiopatia dilatada ou hipertrófica, níveis de cobre no endotélio, fatores genéticos, tais como a consanguinidade na criação, toxicologia e aspectos farmacológicos. A ruptura aórtica mostra semelhança com hemorragia pulmonar induzida pelo exercício. Em conclusão, alterações degenerativas discretas das fibras elásticas da íntima da aorta parecem predispor a ruptura da parede da aorta, no momento da pressão máxima de sangue durante o exercício determinando o consequente colapso e morte do cavalo atleta...

Oxidative profiles of endurance horses racing different distances / Perfil oxidativo em cavalos de enduro competindo em diferentes distâncias

Increased oxidative stress during prolonged endurance exercises may result in muscle damage, fatigue and decreased performance. An adequate stress response during training is critical to obtain improved results and high animal welfare standards. The aim of this study was to evaluate the red blood cell haemolysate concentrations of superoxide dismutase (SOD), glutathione peroxidase (GPx), reduced glutathione (GSH) and catalase (CAT) and the plasma concentrations of malondialdehyde (MDA) from endurance horses in different distances at high speed in a tropical climate. Fifteen horses were tested; five at 160km (18.54 - 17.16km/h race speed), five at 120km (21.53 - 17km/h race speed) and five at 80km (20.06 - 18.01km/h race speed). Blood samples were collected at rest, immediately after and three hours after the horses left the final vet check and three, seven and fourteen days after the race. No significant increases (P > 0.05) in the levels of SOD, GPx, GSH, CAT or MDA were observed for any of the times or distances examined. Based on these observations, we conclude that reactive oxygen species (ROS) formation during exercise evokes specific adaptations, such as increased antioxidant/oxidative damage-repairing enzyme activity, increased resistance to oxidative stress and lower levels of oxidative damage...

Aumento do estresse oxidativo durante o exercício prolongado pode resultar em fadiga muscular, lesões e diminuição do desempenho. Uma adequada resposta a esse estresse durante o treinamento é fundamental para a obtenção de melhores resultados e bem-estar dos animais. O objetivo deste estudo foi avaliar a concentração de superóxido dismutase (SOD), glutationa peroxidase (GPx), glutationa reduzida (GSH) e catalase (CAT) no hemolisado sanguíneo e malondialdeído (MDA) plasmático em cavalos de enduro correndo em diferentes distâncias, com alta média de velocidade, em clima tropical. Quinze cavalos foram testados, cinco em 160km (18.54-17.16km/h), cinco em 120km (21.53-17km/h) e cinco em 80km (20.06-18.01km/h). Amostras de sangue foram coletadas em repouso, imediatamente e três horas depois que os cavalos passaram pela inspeção veterinária final e três, sete e 14 dias após a corrida. Não houve aumentos significativos (P>0,05) dos níveis de SOD, GPx, GSH, CAT ou MDA em nenhum tempo nem distâncias analisadas. Com base nessas observações, pode-se concluir que as espécies reativas de oxigênio (ROS) formadas durante o exercício provocam adaptações específicas, tais como atividade antioxidante aumentada da enzima, maior resistência ao estresse oxidativo e menores níveis de danos oxidativos...

Oxidative metabolism and muscle biochemical profile of polo horses supplemented with an ADE vitamin complex / Metabolismo oxidativo e perfil bioquímico muscular de cavalos de pólo suplementados com complexo vitamínico ADE

Horses used for the game of polo experience abrupt and frequent changes in exercise intensity. To meet this variable energy demand, the horses use both aerobic and anaerobic pathways in varying proportions and intensities. In this context, there must be a balance between the formation of reactive oxygen species (ROS) and the action of antioxidants to prevent oxidative stress and its consequences. The effect of supplementation with an ADE vitamin complex on oxidative metabolism was evaluated in 18 crossbred horses randomly divided between a treated group (TG) and a control group (CG). The TG animals received the ADE vitamin complex (1mL/50 kg of body weight) by deep intramuscular injection at 30 and 15 days before the game. The CG horses received 10ml of saline by the same administration route and schedule. During the polo match, the animals played for a total of 7.5 min. Blood samples were collected on the same days as the treatments were administered, and immediately before and at 15, 90 and 180 minutes after the game. The concentrations of creatine phosphokinase (CK), lactate dehydrogenase (LDH), lactate, glucose, aspartate aminotransferase (AST), glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) were measured in the blood samples. After the game, the TG demonstrated higher levels of AST, lactate and glucose than the CG, suggesting more efficient energy use by the treated animals. The higher GSH and lower lactate levels in the TG before the game suggest the presence of a greater antioxidant supply in the treated animals. The maintenance of the MDA levels indicates that neither of the groups exhibited oxidative stress.

O jogo de pólo se caracteriza por mudanças abruptas e frequentes na intensidade do exercício dos cavalos. Para satisfazer esta demanda inconstante de energia, os animais utilizam as vias aeróbia e anaeróbia em proporções e intensidade variáveis. Neste contexto deve haver equilíbrio entre a formação das espécies reativas de oxigênio (EROs) e a ação das substâncias antioxidantes a fim de evitar o estresse oxidativo e suas consequências. Avaliou-se o efeito da suplementação com vitaminas ADE no metabolismo oxidativo destes animais. Para tanto, 18 equinos mestiços foram distribuídos aleatoriamente em dois grupos: tratado e controle (GT) e controle (GC).Os animais do GT receberam complexo vitamínico ADE (1 mL/50 kg de peso vivo) pela via intramuscular profunda aos 30 e 15 dias antes do jogo. Os cavalos do GC receberam, pela mesma via de administração e nos mesmos momentos, 10mL de solução fisiológica. Os animais jogaram um tempo de 7,5min. Foram coletadas amostras de sangue nos mesmos dias de tratamento e imediatamente antes e aos 15, 90 e 180 minutos após o jogo. Foram determinadas as concentrações sanguíneas de CK, LDH, lactato, glicose, AST, GSH, SOD e MDA. Após o jogo o GT apresentou maiores valores para AST, lactato e glicemia que o GC, sugerindo melhor aproveitamento energético dos animais tratados. Os valores maiores de GSH e menores de lactato no GT antes da prova sugerem maior aporte antioxidante nos animais tratados. A manutenção dos teores de MDA indica que nenhum dos grupos entrou em estresse oxidativo.

The role of veterinarians in equestrian sport: a comparative review of ethical issues surrounding human and equine sports medicine.

Veterinarians have a key role in providing medical care for sports horses during and between competitions, but the standard client:veterinarian relationship that exists in companion and production animal medicine is distorted by the involvement of third parties in sports medicine, resulting in distinct ethical dilemmas which warrant focused academic attention. By comparing the existing literature on human sports medicine, this article reviews the ethical dilemmas which face veterinarians treating equine athletes, and the role of regulators in contributing to or resolving those dilemmas. Major ethical dilemmas occur both between and during competitions. These include conflicts of responsibility, conflicts between the need for client confidentiality and the need to share information in order to maximise animal welfare, and the need for an evidence base for treatment. Although many of the ethical problems faced in human and equine sports medicine are similar, the duty conferred upon a veterinarian by the licensing authority to ensure the welfare of animals committed to his or her care requires different obligations to those of a human sports medicine doctor. Suggested improvements to current practice which would help to address ethical dilemmas in equine sports medicine include an enhanced system for recording equine injuries, the use of professional Codes of Conduct and Codes of Ethics to establish acceptable responses to common ethical problems, and insistence that treatment of equine athletes is evidence-based (so far as possible) rather than economics-driven.