Pre-Ride Biomarkers and Endurance Horse Welfare: Analyzing the Impact of the Elimination of Superoxide Dismutase, δ-Aminolevulinic-Dehydratase, Thiobarbituric Acid Reactive Substances, Iron, and Serum Amyloid A Levels in Elite 160 km Endurance Rides.

High elimination rates and concerns for horse welfare are important issues in endurance riding. Improved understanding of the causes of elimination could increase completion rates in this sport. We have identified pre-ride laboratory risk factors that enable an assessment of potential elimination before the ride. A longitudinal cohort study was performed among 49 healthy horses competing in the 160 km endurance ride at the 2016 World Championship of Endurance Riding in Samorin/Slovakia. Blood samples were taken before the event. For statistical evaluation, horses were categorized into three groups: finishers, lame horses, and metabolically eliminated horses. Risk factors were calculated for each group using multinominal logistic regression. δ-Aminolevulinic-dehydratase (ALAD), thiobarbituric acid reactive substances (TBARSs), iron, and serum amyloid A (SAA) were measured and did not show an impact on the race outcome, but elevated pre-ride superoxide dismutase (SOD) was shown to have an effect on lameness elimination (p = 0.011). It might serve as an indicator for withdrawing horses at risk of later elimination before endurance rides, ultimately resulting in lower elimination rates and an increase in overall horse welfare.

Pre-race and race management impacts serum muscle enzyme activity in Australian endurance horses.

BACKGROUND: Marked increases in serum muscle enzyme activity can occur in endurance horses but the diagnostic certainty in predicting cases of myopathy is unclear. Improved understanding of horse management effects on serum muscle enzyme activity as markers of muscle health would assist interpretation of serum muscle enzyme activity and guide management to reduce myopathy risk. OBJECTIVES: To investigate associations between serum muscle enzyme activity and management factors in endurance horses. STUDY DESIGN: Cross-sectional study. METHODS: One hundred endurance horses competing in four endurance events (offering distances of 20-120 km) in south-eastern Australia were observed. Data were collected from official horse logbooks, pre-and post-race serum samples, an owner questionnaire of pre-race and race management of horses and the Australian Endurance Riders Association results database. Multivariable linear regression modelling tested associations between management factors and serum muscle enzyme activity. RESULTS: First leg speed, distance raced, number of rest days pre-race, and pre-race activity of aspartate aminotransferase (AST) and creatine kinase (CK) explained 47.3% of the variance in post-race CK. As first leg speed increased by 1 km/h, CK activity increased by 25.8% (95% CI 11%-35%). Race distances >80 km increased post-race CK activity by 124% (95% CI 116%-145%). Each additional pre-race rest day increased post-race CK activity by 30.5% (95% CI 11%-42%). Modelling a 10% increase in pre-race CK and pre-race AST activity was associated with post-race CK activity increasing by 7.3% (95% CI 3%-14.4%) and 8.5% (95% CI 0.3%-14.2%) respectively. Horses experiencing training distances >40 km and a greater number of rest days prior to race day developed increased pre-race AST and CK activity respectively. MAIN LIMITATIONS: Owner questionnaires may be subject to bias. Limited data were available to model ride terrain, horse fitness, ration detail and myopathy. Muscle biopsies were not used to confirm myopathy. CONCLUSIONS: Nearly half of the variation in post-race CK activity observed can be attributed to management factors unrelated to myopathy, suggesting increased CK activity may not be pathognomonic for myopathy. We advise caution in relying solely on serum muscle enzyme activity for diagnosis of myopathy until the strength of association between CK and myopathy is further ascertained in future studies.

Age and Hydration of Competing Horses Influence the Outcome of Elite 160 km Endurance Rides.

High elimination rates and the concern for horse welfare are important issues in endurance riding. An improved understanding of the causes of elimination could increase completion rates in this sport. We have identified pre-ride risk factors that allow an assessment of potential elimination before the ride. A longitudinal cohort study was performed among 49 healthy horses competing in the 160 km endurance ride at the 2016 World Championship of Endurance Riding in Samorin/Slovakia. Blood samples were drawn before the ride. For statistical evaluation, horses were categorized in three groups: finishers, lame and metabolically eliminated horses. Risk factors were calculated for each group using multinomial logistic regression. A 1% increase in hematocrit levels was associated with a higher OR for elimination (lameness: OR 1.26, p = 0.017; metabolic: OR 1.34, p = 0.010). Furthermore, increased potassium values correlated negatively with the race outcome. For a 1 mmol/l increase in potassium, the lameness OR was 4.21, p = 0.039 and metabolic OR was 1.15, p = 0.848. Eight-year-old horses had a 100% elimination rate and survival analyses showed a significantly higher hazard for elimination (p = 0.025). We thus conclude that age and hydration affect the outcome of elite endurance rides. Further investigation of age as a risk factor seems to be clinically relevant and adjustments of FEI qualification modes may be appropriate.

Evaluation of two models of saddles on the back of Arabian horses through thermography / Avaliação de dois modelos de selas sobre o dorso de cavalos Árabes com o emprego da termografia

Dorsopathies are common causes of decreased performance in athletic horses of various modalities, and inadequate or poorly adjusted saddles can lead to the onset of injuries and low back pain. The present study, searching to find the most appropriate saddle, evaluated the pressure determined from the panels of two saddle models most commonly used in endurance Arab horse on the thoracolumbar region. For the study, six Arabian geldings were used, weighing 390 ± 4.2 and 2.1 ± age 8 years, conditioned to endurance races, and two saddle models, English and Western. The horses were submitted to the work riding on a sandy lane by the same experienced rider who weighed 76 kg. Thermography was performed before and after each exercise session. The obtained data were analyzed through Student's paired t-test at 5% of significance. After exercise, there was a mean temperature difference between the contact areas of the right and left of the sweepers of two saddles compared, with the English saddle showing higher temperatures. Therefore, the Western saddle model, which has wider panels, despite not being a preferred model of endure riders, has proved to be more suitable for Arabian horse work.(AU)

As dorsopatias são causas comuns de diminuição de desempenho em cavalos atletas de várias modalidades e a sela inadequada ou mal ajustada pode levar ao aparecimento de lesões e dor lombar. O presente trabalho avaliou a pressão que os suadores dos dois modelos de sela mais comumente utilizados em cavalos Árabes de enduro exercem sobre a região toracolombar desses animais de modo a sugerir o uso do que fosse mais adequado. Foram utilizados seis cavalos da raça Árabe, machos castrados, com peso de 390 ± 4,2 e idade 8 ± 2,1 anos, condicionados para as provas enduro de velocidade livre e dois modelos de sela, a Inglesa e a Western. Os cavalos foram submetidos ao trabalho montado em pista de areia pelo mesmo cavaleiro, experiente, que pesou 76 kg. Foi realizada a termografia antes e depois das sessões de exercício. Os dados obtidos foram analisados através de teste T pareado de Student a 5% de significância. Houve diferença de temperatura média, após o exercício, entre as áreas de contato dos suadores direito e esquerdo da sela Inglesa e da sela Western, quando comparados, sendo que a sela Inglesa apresentou maiores temperaturas. Portanto, o modelo de sela Western, que possui suadores largos, embora não seja o modelo de preferência dos cavaleiros de enduro, mostrou-se mais adequado para o trabalho de cavalos Árabes.(AU)

Resposta hematológica de cavalos de enduro, que correram diferentes distâncias, no período pós-prova / Hematologic response of endurance horses that ran different distances in the post race period

O objetivo deste trabalho foi estudar as alterações hematológicas após provas de enduro de diferentes distâncias até 14 dias após a prova, período de recuperação metabólica e musculoesquelética, as quais ocorrem em cavalos treinados e que concluíram as competições em boas condições de saúde. Foram avaliados 32 cavalos Árabes, com 400 (±32kg), treinados para provas de enduro, que competiram em quatro provas nas categorias velocidade livre de 80km (n=13), 120km (n=14) e 160km (n=5). Amostras de sangue foram coletadas antes da largada (M0), imediatamente após a saída da última inspeção veterinária (M1) e três horas após (M2). Já nos respectivos haras, foram coletadas amostras aos três (M3), sete (M4) e 14 (M5) dias após a prova. Houve aumento dos valores de eritrócitos, hemoglobina e hematócrito após o término da prova em todos os cavalos, e esse aumento se manteve até três horas após a prova nos cavalos de 120 e 80km. Houve aumento do número de plaquetas em todos os cavalos, que permaneceu elevado até três horas após a prova e normalizou-se a partir do terceiro dia. Houve efeito (P<0,05) da prova sobre as variáveis eritrócitos, hemoglobina e hematócrito, do número de plaquetas, aumento na contagem de neutrófilos e diminuição da contagem de linfócitos após o término da prova e três horas depois, retornando ao normal a partir do terceiro dia. Um dado inédito deste estudo foi o aumento de eosinófilos sanguíneos após três dias da competição, que se manteve até o sétimo dia. Esse fato pode sinalizar a participação dessas células no processo de reparação. A avaliação dos componentes sanguíneos se mostrou uma importante ferramenta para a avaliação da recuperação dos animais. Como só foram avaliados cavalos que completaram a prova, as alterações encontradas após dias do esforço sinalizam a relevância de se estudarem melhor as etapas e os componentes da recuperação metabólica e muscular, a fim de não se cometerem excessos, retornando esses animais no tempo correto.(AU)

The aim of this study was to analyze the hematological changes after endurance races from different distances up to 14 days, a period of metabolic and musculoskeletal recovery that occured in trained horses that finished the competitions in a good health. A total of 32 Arabian horses were evaluated, with 400 (±32kg) trained for endurance races, who competed in four events in free speed categories 80 km (n = 13), 120km (n = 14) and 160km (n = 5). Blood samples were collected before the start (M0), immediately after leaving the last veterinary inspection (M1) and three hours later (M2). Already at their farms, samples were taken at three (M3), seven (M4) and 14 (M5) days after the race. There was an increase of values of erythrocytes, hemoglobin and packed cell volume after the end of the race in all horses and this increase was maintained until three hours after the race in the of 120 and 80km horses. There was an increase in the number of platelets in all horses, which remained elevated up to 3 hours after the test and normalized on the third day. All horses underwent increase in neutrophil counts and decreased lymphocyte count immediately after the race and three hours later, returning to normal after the third day. There was also pronounced increase in the number of eosinophils in all horses on the third day, which lasted until the seventh after the race. An unheard of data of this study was an increase in blood eosinophils after three days of competition that remained until the seventh day. This may signal the participation of these cells in the repair process. The evaluation of blood components proved to be an important tool for the assessment of recovery of the animals. As only horses that finished the race were evaluated, the changes found within days of effort, indicate the importance of further studies to investigate the steps and components of the metabolic and muscular recovery, in order not to commit excesses, returning the animals to activity at the right time.(AU)